OBJECTIVES: The coronavirus disease (COVID-19) outbreak has catastrophically threatened public health worldwide and presented great challenges for clinicians. To date, no specific drugs are available against severe acute respiratory syndrome coronavirus 2. Mesenchymal stem cells (MSCs) appear to be a promising cell therapy owing to their potent modulatory effects on reducing and healing inflammation-induced lung and other tissue injuries. The present pilot study aimed to explore the therapeutic potential and safety of MSCs isolated from healthy cord tissues in the treatment of patients with COVID-19. METHODS: Twelve patients with COVID-19 treated with MSCs plus conventional therapy and 13 treated with conventional therapy alone (control) were included. The efficacy of MSC infusion was evaluated by changes in oxygenation index, clinical chemistry and hematology tests, immunoglobulin (Ig) levels, and pulmonary computerized tomography (CT) imaging. The safety of MSC infusion was evaluated based on the occurrence of allergic reactions and serious adverse events. RESULTS: The MSC-treated group demonstrated significantly improved oxygenation index. The area of pulmonary inflammation decreased significantly, and the CT number in the inflammatory area tended to be restored. Decreased IgM levels were also observed after MSC therapy. Laboratory biomarker levels at baseline and after therapy showed no significant changes in either the MSC-treated or control group. CONCLUSION: Intravenous infusion of MSCs in patients with COVID-19 was effective and well tolerated. Further studies involving a large cohort or randomized controlled trials are warranted.

A solid-phase extraction (SPE) method based on conductive polypyrrole (PPy) nanofibers which were fabricated by electrospinning and in situ polymerization was developed. PPy nanofibers-mediated SPE followed by high performance liquid chromatography (HPLC) was used for the determination of three synthetic estrogens, namely diethylstilbestrol (DES), dienestrol (DIS), or hexestrol (HS) in milk sample. Extraction conditions including extraction nanofibers, donor solution pH and salt concentration were optimized. The target compounds were extracted from a 0.5 mL aqueous sample at pH 5.0 through PPy fibers, and then were eluted with 0.1 mL methanol. After extraction, the eluant was directly injected into an HPLC system for detection. Under the optimized extraction conditions, a large enrichment factor was achieved for three estrogens. The limit of detection (LOD) at a signal to noise ratio (S/N) of 3 ranged from 0.02 to 0.05 µg mL-1 for the estrogens in milk sample.

Polystyrene (PS) nanofibers incorporated with ion-pair (IP) reagent, e.g., sodium dodecyl sulfonate (SDSn), were developed as functional adsorbents for the solid-phase extraction (SPE) of ionic neurotransmitter such as 5-hydroxytryptamine (5-HT), prior to the determination by high performance liquid chromatography-fluorescence detection (HPLC-FLD). A comprehensive study was initiated to optimize the preconcentration step by exploring the main factors that affect the extraction/preconcentration efficiency of 5-HT, such as the composition of nanofibers, eluent and its volume, amount of adsorbent, pH and ionic strength. The validity of this method was investigated and optimal analytical performance was achieved including a wide dynamic range of 0.50-200 ng mL-1, detection limits of 0.50 ng mL–1 and precision (as RSD%) lower than 4% for both intra-day and inter-day assays. This method was then applied to the determination of 5-HT in human plasma with satisfactory results.