Comparison of mechanical properties between Nice knot,Modified Nice knot,and surgeon's knot

BackgroundThe success of surgical repairs rely on the effectiveness and integrity of the surgical knots used to secure the repair. The purpose of this study is to examine and compare the performance of the Nice knot, the modified Nice knot, and a commonly used combination of surgeons' and square knots with respect to cyclic loading and load-to-failure usiflueng a high-strength suture composed of ultra-high molecular weight polyethylene in the hands of experienced surgeons.MethodsTwo experienced surgeons threw 3 different knot types 9 times, consisting of the Nice knot, modified Nice knot, and a surgeon's knot utilizing Ultrabraid #2 sutures. Each knot was subject to cyclic loading and load to failure testing.FindingsBoth surgeons had similar displacement data for the surgeon's knot, while the identity of the surgeon impacted displacement for the Nice knot (p = 0.03) and the modified Nice knot (p = 0.0002). The load to failure for the modified Nice knot (p < 0.001) and the Nice knot (p = 0.001) were significantly impacted by the surgeon tying the knot, while the surgeon's knot was not. Specimens failed where the sutures passed through the loop at the “base” of the knot.InterpretationsThe strength and integrity of complex surgical knots are variable between surgeons. While the proposed Modified Nice Knot has a theoretical advantage because the half hitches reinforce the primary knot, in load to failure testing both the Modified Nice Knot and the Nice Knot failed where the suture passed through the loop in the primary knot.     

Preclinical evaluation of a plant-derived SARS-CoV-2 subunit vaccine: Protective efficacy,immunogenicity, safety,and toxicity

Coronavirus disease 2019 (COVID-19) is an acute respiratory illness caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The prevention of SARS-CoV-2 transmission has become a global priority. Previously, we showed that a protein subunit vaccine that was developed based on the fusion of the SARS-CoV-2 receptor-binding domain (RBD) to the Fc portion of human IgG1 (RBD-Fc), produced in Nicotiana benthamiana, and adjuvanted with alum, namely, Baiya SARS-CoV-2 Vax 1, induced potent immunological responses in both mice and cynomolgus monkeys. Hence, this study evaluated the protective efficacy, safety, and toxicity of Baiya SARS-CoV-2 Vax 1 in K18-hACE2 mice, monkeys and Wistar rats. Two doses of vaccine were administered three weeks apart on Days 0 and 21. The administration of the vaccine to K18-hACE2 mice reduced viral loads in the lungs and brains of the vaccinated animals and protected the mice against challenge with SARS-CoV-2. In monkeys, the results of safety pharmacology tests, general clinical observations, and a core battery of studies of three vital systems, namely, the central nervous, cardiovascular, and respiratory systems, did not reveal any safety concerns. The toxicology study of the vaccine in rats showed no vaccine-related pathological changes, and all the animals remained healthy under the conditions of this study. Furthermore, the vaccine did not cause any abnormal toxicity in rats and was clinically tolerated even at the highest tested concentration. In addition, general health status, body temperature, local toxicity at the administration site, hematology, and blood chemistry parameters were also monitored. Overall, this work presents the results of the first systematic study of the safety profile of a plant-derived vaccine, Baiya SARS-CoV-2 Vax 1; this approach can be considered a viable strategy for the development of vaccines against COVID-19.