Pulmonary contusion mimicking COVID-19: A case report.

BACKGROUND: Coronavirus disease 2019 (COVID-19) is a major public health emergency with obvious characteristics of human-to-human transmission, and there are infective asymptomatic carriers. Early identification and proper management of patients with COVID-19 are important. Features in chest computed tomography (CT) can facilitate identifying newly infected individuals. However, CT findings of some lung contusions are similar to those of COVID-19, as shown in the present case. CASE SUMMARY: A 46-year-old woman was admitted to hospital for backache and foot pain caused by a fall injury 1 d before hospitalization. She was suspected of having COVID-19, since there was a confirmed COVID-19 case near her residence. But she had no fever, cough, chest tightness, difficult breathing, nausea, vomiting, or diarrhea, etc. On physical examination, the lower posterior chest of both sides showed dullness on percussion and moist rales at the end of inspiration on auscultation. The white blood cell count and lymphocyte count were 10.88 × 109/L and 1.04 × 109/L, respectively. CT performed on February 7, 2020 revealed that both lungs were scattered with patchy ground-glass opacity. The patient was diagnosed with pulmonary contusion with thoracic spinal fracture (T12), calcaneal fracture, and pelvic fracture. On day 9 after conservative treatment, her condition was alleviated. On review of the chest CT, the previous shadows were significantly reduced. CONCLUSION: Differential diagnosis of lung contusion and COVID-19 must be emphasized. Both conditions require effective prompt actions, especially COVID-19.

Heparin nanomodification improves biocompatibility and biomechanical stability of decellularized vascular scaffolds.

Biocompatibility and biomechanical stability are two of the main obstacles limiting the effectiveness of vascular scaffolds. To improve the biomechanical stability and biocompatibility of these scaffolds, we created a heparin-nanomodified acellular bovine jugular vein scaffold by alternating linkage of heparin and dihydroxy-iron via self-assembly. Features of the scaffold were evaluated in vitro and in vivo. Heparin was firmly linked to and formed nanoscale coatings around the fibers of the scaffold, and the amount of heparin linked was about 808 ± 86 µg/cm(2) (101 ± 11 USP/cm(2)) per assembly cycle. The scaffolds showed significantly strengthened biomechanical stability with sustained release of heparin for several weeks in vitro. Importantly, the modified scaffolds showed significantly reduced platelet adhesion, stimulated proliferation of endothelial cells in vitro, and reduced calcification in a subcutaneous implantation rat model in vivo. Heparin nanomodification improves the biocompatibility and biomechanical stability of vascular scaffolds.

[Heparin-iron complex multilayer nanomodification improves hemocompatibility of decellular xenograft].

OBJECTIVE: To improve the hemocompatibility of decellular vascular matrix via heparin-iron complex multilayers (HICMs) nanomodification. METHODS: A novel thrombo-resistant surface for decellular xenograft was developed by alternating linkage of dihydroxy-iron and heparin to decellular bovine jugular vein (DC-BJV), and its surface characterization, biomechanical stability and hemocompatibility were detected by scanning electron microscopy, tensile test and hemocompatibility evaluation, respectively. RESULTS: A toluidine blue colorimetric method indicated the amount of linked heparin was about (808±86) µg/cm2 per assembly-cycle. Scanning electron microscopic (SEM) images proved that HICMs were uniformly linked to and formed nanoscale films around the fibrils of DC-BJV. Toluidine blue staining histologic images showed that HICMs were linked mainly to DC-BJV surfaces. Washing test showed that the release of heparin was (281±43), (422 ± 60), (729±81), (1053±116), (1317±157), (1618±187) and (1945 ± 268 ) µg/cm(2) at 1 day, 1, 2, 3, 4, 6 and 8 week washing, respectively. Tensile tests showed an increased biomechanical stability. Hemocompatibility evaluations showed that PT and APTT of all the trial groups were above the normal reference ranges and that mean platelet count per 10000 µm2 area was 8±4 for HICMs layer-by-layer modified BJV (LBL-BJV) vs 48±16 for DC-BJV. CONCLUSION: HICMs are firmly linked to DC-BJV, and can form nanoscale thrombo-resistant films, which yield a sustained release of heparin. HICMs nanomodification improves the hemocompatibility of decellular xenograft.

Controlled release of chitosan/heparin nanoparticle-delivered VEGF enhances regeneration of decellularized tissue-engineered scaffolds.

Regeneration deficiency is one of the main obstacles limiting the effectiveness of tissue-engineered scaffolds. To develop scaffolds that are capable of accelerating regeneration, we created a heparin/chitosan nanoparticle-immobilized decellularized bovine jugular vein scaffold to increase the loading capacity and allow for controlled release of vascular endothelial growth factor (VEGF). The vascularization of the scaffold was evaluated in vitro and in vivo. The functional nanoparticles were prepared by physical self-assembly with a diameter of 67-132 nm, positive charge, and a zeta potential of ∼30 mV and then the nanoparticles were successfully immobilized to the nanofibers of scaffolds by ethylcarbodiimide hydrochloride/hydroxysulfosuccinimide modification. The scaffolds immobilized with heparin/chitosan nanoparticles exhibited highly effective localization and sustained release of VEGF for several weeks in vitro. This modified scaffold significantly stimulated endothelial cells' proliferation in vitro. Importantly, utilization of heparin/chitosan nanoparticles to localize VEGF significantly increased fibroblast infiltration, extracellular matrix production, and accelerated vascularization in mouse subcutaneous implantation model in vivo. This study provided a novel and promising system for accelerated regeneration of tissue-engineering scaffolds.