Recurrence of SARS-CoV-2 nucleic acid positive test in patients with COVID-19: a report of two cases
BMC PULMONARY MEDICINE
Authors: Wu, Jian; Cheng, Juan; Shi, Xiaowei; Liu, Jun; Huang, Biao; Zhao, Xinguo; Qiu, Yuanwang; Yu, Jiong; Cao, Hongcui; Li, Lanjuan
Background The recurrence of positive SARS-CoV-2 nucleic acid test results in patients with COVID-19 is becoming more important and warrants more attention. Case presentation This study reports 2 cases, a child with mild COVID-19 and an adult female with moderate COVID-19, who were discharged after three consecutive negative nucleic acid tests and were later readmitted to the hospital for recurrence of SARS-CoV-2 nucleic acid positivity. By tracking the patients' symptoms, serum antibodies, and imaging manifestations after readmission, we found that they showed a trend of gradual improvement and recovery throughout treatment. They were cured without additional treatment, with the appearance of antibodies and the recovery of immune functions. Conclusions It is deemed extremely necessary to improve the discharge standard of care. At the same time, nucleic acid detection is recommended to increase the dynamic monitoring of serum antibodies and imaging, strengthen the management of discharged patients, and appropriately extend the home or centralized isolation time.
Effect of whey protein isolate on the stability and antioxidant capacity of blueberry anthocyanins: A mechanistic and in vitro simulation study
Authors: Zang, Zhihuan; Chou, Shurui; Tian, Jinlong; Lang, Yuxi; Shen, Yixiao; Ran, Xulong; Gao, Ningxuan; Li, Bin
The processing stability and antioxidant capacity of blueberry anthocyanins (ANs) in the presence of whey protein isolate (WPI) were examined. WPI was found to enhance both the stability and antioxidant activity of ANs during processing and simulated in vitro digestion, especially at a concentration of 0.15 mgmL(-1). Fluorescence and ultraviolet-visible absorption spectroscopy showed that ANs were primarily stabilized by hydrophobic forces between WPI and malvidin-3-O-galactoside (M3G), the major anthocyanin monomer. Circular dichroism and Fourier-transform infrared spectroscopy confirmed that the structure of WPI changed and the microenvironments of certain amino acid residues were modulated by non-covalent binding to M3G; furthermore, fewer alpha-helices and more beta-sheets were formed. Molecular docking studies revealed that WPI, especially immunoglobulin (IgG), contributed the most to ANs stability via hydrogen bonds and hydrophobic forces according to molecular docking scores ( - 141.30 kcal/mol). These results provided an important fundamental basis for improving the stabilities of ANs in milk systems.