30-Day Morbidity and Mortality of Bariatric Surgery During the COVID-19 Pandemic: a Multinational Cohort Study of 7704 Patients from 42 Countries

BACKGROUND

There are data on the safety of cancer surgery and the efficacy of preventive strategies on the prevention of postoperative symptomatic COVID-19 in these patients. But there is little such data for any elective surgery. The main objectives of this study were to examine the safety of bariatric surgery (BS) during the coronavirus disease 2019 (COVID-19) pandemic and to determine the efficacy of perioperative COVID-19 protective strategies on postoperative symptomatic COVID-19 rates.

METHODS

We conducted an international cohort study to determine all-cause and COVID-19-specific 30-day morbidity and mortality of BS performed between 01/05/2020 and 31/10/2020.

RESULTS

Four hundred ninety-nine surgeons from 185 centres in 42 countries provided data on 7704 patients. Elective primary BS (n = 7084) was associated with a 30-day morbidity of 6.76% (n = 479) and a 30-day mortality of 0.14% (n = 10). Emergency BS, revisional BS, insulin-treated type 2 diabetes, and untreated obstructive sleep apnoea were associated with increased complications on multivariable analysis. Forty-three patients developed symptomatic COVID-19 postoperatively, with a higher risk in non-whites. Preoperative self-isolation, preoperative testing for SARS-CoV-2, and surgery in institutions not concurrently treating COVID-19 patients did not reduce the incidence of postoperative COVID-19. Postoperative symptomatic COVID-19 was more likely if the surgery was performed during a COVID-19 peak in that country.

CONCLUSIONS

BS can be performed safely during the COVID-19 pandemic with appropriate perioperative protocols. There was no relationship between preoperative testing for COVID-19 and self-isolation with symptomatic postoperative COVID-19. The risk of postoperative COVID-19 risk was greater in non-whites or if BS was performed during a local peak.

30-Day Morbidity and Mortality of Bariatric Surgery During the COVID-19 Pandemic: a Multinational Cohort Study of 7704 Patients from 42 Countries

BACKGROUND

There are data on the safety of cancer surgery and the efficacy of preventive strategies on the prevention of postoperative symptomatic COVID-19 in these patients. But there is little such data for any elective surgery. The main objectives of this study were to examine the safety of bariatric surgery (BS) during the coronavirus disease 2019 (COVID-19) pandemic and to determine the efficacy of perioperative COVID-19 protective strategies on postoperative symptomatic COVID-19 rates.

METHODS

We conducted an international cohort study to determine all-cause and COVID-19-specific 30-day morbidity and mortality of BS performed between 01/05/2020 and 31/10/2020.

RESULTS

Four hundred ninety-nine surgeons from 185 centres in 42 countries provided data on 7704 patients. Elective primary BS (n = 7084) was associated with a 30-day morbidity of 6.76% (n = 479) and a 30-day mortality of 0.14% (n = 10). Emergency BS, revisional BS, insulin-treated type 2 diabetes, and untreated obstructive sleep apnoea were associated with increased complications on multivariable analysis. Forty-three patients developed symptomatic COVID-19 postoperatively, with a higher risk in non-whites. Preoperative self-isolation, preoperative testing for SARS-CoV-2, and surgery in institutions not concurrently treating COVID-19 patients did not reduce the incidence of postoperative COVID-19. Postoperative symptomatic COVID-19 was more likely if the surgery was performed during a COVID-19 peak in that country.

CONCLUSIONS

BS can be performed safely during the COVID-19 pandemic with appropriate perioperative protocols. There was no relationship between preoperative testing for COVID-19 and self-isolation with symptomatic postoperative COVID-19. The risk of postoperative COVID-19 risk was greater in non-whites or if BS was performed during a local peak.

Protein-polyelectrolyte complexes to improve the biological activity of proteins in layer-by-layer assemblies

A standard method of protein immobilization is proposed, based on the use of protein-polyelectrolyte complexes (PPCs) as building blocks for layer-by-layer assembly. Thicker multilayers, with a higher polyelectrolyte fraction, are obtained with PPCs compared to single protein molecules. Biological activity is not only maintained, but specific activity is also higher, as demonstrated for lysozyme-poly(styrene sulfonate) complexes. This is attributed to the more hydrated state of the assemblies. This new method of protein immobilization opens up perspectives for biotechnology and biomedical applications.

Chitosan nanoparticles for siRNA delivery: optimizing formulation to increase stability and efficiency

This study aims at developing chitosan-based nanoparticles suitable for an intravenous administration of small interfering RNA (siRNA) able to achieve (i) high gene silencing without cytotoxicity and (ii) stability in biological media including blood. Therefore, the influence of chitosan/tripolyphosphate ratio, chitosan physicochemical properties, PEGylation of chitosan as well as the addition of an endosomal disrupting agent and a negatively charged polymer was assessed. The gene silencing activity and cytotoxicity were evaluated on B16 melanoma cells expressing luciferase. We monitored the integrity and the size behavior of siRNA nanoparticles in human plasma using fluorescence fluctuation spectroscopy and single particle tracking respectively. The presence of PEGylated chitosan and poly(ethylene imine) was essential for high levels of gene silencing in vitro. Chitosan nanoparticles immediately released siRNA in plasma while the inclusion of hyaluronic acid and high amount of poly(ethylene glycol) in the formulation improved the stability of the particles. The developed formulations of PEGylated chitosan-based nanoparticles that achieve high gene silencing in vitro, low cytotoxicity and high stability in plasma could be promising for intravenous delivery of siRNA.

Elastic modulus of halloysite nanotubes

This work reports measurements of the elastic modulus of halloysite nanotubes. Nanoscale three-point bending tests were performed on individual nanotubes using an atomic force microscope. Nanotubes exhibit elastic behaviour at small deformations. The stiffness of the tubes, and hence their elastic modulus, was deduced from force curve measurements using an appropriate mechanical model. The boundary conditions were also identified by recording the stiffness profile of a tube along its suspended length. An average elastic modulus of 140 GPa is obtained for a set of tubes with outer diameters ranging between 50 and 160 nm. Moreover, the elastic modulus increases with decreasing outer diameter, with a steep jump below 50 nm. The size dependence of the elastic modulus may be attributed to: (i) surface tension effects for thinner tubes and (ii) a non-negligible contribution of shear deformations to the total deflection for larger tubes.

The origin of a ‘true’ worker caste in termites: mapping the real world on the phylogenetic tree

The evolution of the 'true' worker caste in termites is not decisively inferred by coding and mapping both this character and the foraging behaviour on a phylogenetic tree. Answering to Thompson et al. (2000, 2003), and with reference to Grandcolas and D'Haese (2002), we show that this indecisive inference depends on the correct consideration paid to the outgroups. These last ones could be non subsocial cockroaches, or some wood-eating subsocial cockroaches often considered misleadingly as living ancestors, or even any hemimetabolous insects, all of them would be unambiguously lacking 'true' worker caste and pseudergate caste and not showing the 'one-piece' life type foraging behaviour. These statements derive from observing, coding and mapping the real world on the tree without making ad hoc assumptions. In that respect, because termites do not exist in isolation, apart from the tree of life, mapping the character of interest on the tree must be applied to the outgroups as well.