RESUMEN
The SARS-CoV-2 virus has been on a rampage for more than two years. Vaccines in combination with neutralizing antibodies (NAbs) against SARS-CoV-2 carry great hope in the treatment and final elimination of COVID-19. However, the relentless emergence of variants of concern (VOC), including the most recent Omicron variants, presses for novel measures to counter these variants that often show immune evasion. Hereby we developed a targeted photodynamic approach to neutralize SARS-CoV-2 by engineering a genetically encoded photosensitizer (SOPP3) to a diverse list of antibodies targeting the WT spike protein, including human antibodies isolated from a 2003 SARS patient, potent monomeric and multimeric nanobodies targeting RBD, and non-neutralizing antibodies (non-NAbs) targeting the more conserved NTD region. As confirmed by pseudovirus neutralization assay, this targeted photodynamic approach significantly increased the efficacy of these antibodies, especially that of non-NAbs, against not only the WT but also the Delta strain and the heavily immune escape Omicron strain (BA.1). Subsequent measurement of infrared phosphorescence at 1270 nm confirmed the generation of singlet oxygen (1O2) in the photodynamic process. Mass spectroscopy assay uncovered amino acids in the spike protein targeted by 1O2. Impressively, Y145 and H146 form an oxidization "hotspot", which overlaps with the antigenic "supersite" in NTD. Taken together, our study established a targeted photodynamic approach against the SARS-CoV-2 virus and provided mechanistic insights into the photodynamic modification of protein molecules mediated by 1O2.
RESUMEN
Objective:To evaluate three-stage induced membrane technique combined with anterior and posterior double-plate fixation in the treatment of a total talus defect after infection.Methods:Included in this study were 11 patients with talus infection who had been treated at Department of Orthopaedics, Foshan Hospital of Traditional Chinese Medicine from January 2014 to December 2018. They were 8 males and 3 females, aged from 23 to 63 years (mean, 37.0 years). The infection followed re-implantation after open dislocation of total talus in 4 cases, internal fixation for open talus fracture of Gustilo type Ⅲa in 3 cases and surgery of open ankle fracture of Gustilo type Ⅲc in 2 cases, and was complicated with ankle intraarticular tuberculosis in 2 cases. The three-stage operations consisted of debridement, total talus resection, implantation of antibiotic bone cement and vacuum sealing drainage at the first stage, change of bone cement, re-debridement, wound closure or flap covering at the second stage 7 to 10 days later, and reconstruction after infection control using anterior and posterior double-plate fixation and induced membrane technique at the third stage 6 to 12 weeks later. Assessment of lower limb shortening was performed by comparing the full length of the leg between the normal and affected sides; the functions were assessed by comparing the ankle-hindfoot scores of American Orthopedic Foot and Ankle Society (AOFAS) and visual analogue scale (VAS) between preoperation and the final follow-up.Results:The 11 patients were followed up for an average of 24.3 months (from 12.2 to 37.5 months). Superficial skin necrosis was observed in 2 patients and injury to superficial peroneal nerve in one. Absolute calcification of the autograft area was observed in all patients, leading to ankle fusion. The final follow-ups observed no significant difference in the full length of the leg between the normal and affected sides [(380.4±35.5) mm versus (376.3±32.8) mm] ( P>0.05) , a significant increase in the ankle-hindfoot AOFAS scores from preoperative 28.0±3.4 to 72.8±5.4, and a significant decrease in VAS scores from preoperative 5(5,6) to 0(0,1) (all P<0.05). Slight varus developed in 2 patients and slight ankle stiffness in 3; recurrence of infection or breakage of implants was found in none of the patients. Conclusion:Three-stage induced membrane technique combined with anterior and posterior double-plate fixation can effectively control infection of the talus, maintain the length and reconstruct the function of the lower limb after a total talus defect.