A Successful Outcome of Veno-Venous Extracorporeal Membrane Oxygenation in Obese Patients with Respiratory Failure in the Course of COVID-19: A Report of Two Cases.

The use of extracorporeal membrane oxygenation (ECMO) in patients with respiratory failure in the course of COVID-19 indicates its limited efficacy and high mortality rates. It seems that one of the conditions for the success of veno-venous ECMO (VV ECMO) in obese patients with COVID-19 is the correct qualification and rapid implementation of this method. We present two cases of obese patients with acute respiratory distress syndrome (ARDS) as a result of SARS-CoV-2 infection with the successful use of ECMO. Two 41-year-old obese patients (Case 1: BMI 31.5 kg/m2 and Case 2: 44.5 kg/m2), with pneumonia and severe respiratory failure in the course of COVID-19, underwent ECMO therapy. The Extracorporeal Life Support Organization (ELSO) guidelines were used to qualify the patients. Due to the persistence of PaO2/FiO2 rate <80 for 6 h, a decision was made to implement VV ECMO. Both patients were discharged from the intensive care unit (Case 1: on day 35; Case 2: on day 22). Rapid implementation of VV ECMO in middle-aged, obese patients with ARDS in the course of COVID-19 showed a positive outcome.

Solvothermal synthesis of hydrophobic chitin-polyhedral oligomeric silsesquioxane (POSS) nanocomposites.

Chitinous scaffolds isolated from the skeleton of marine sponge Aplysina cauliformis were used as a template for the deposition of polyhedral oligomeric silsesquioxanes (POSS). These chitin-POSS based composites with hydrophobic properties were prepared for the first time using solvothermal synthesis (pH 3, temp 80 °C), and were thoroughly characterized. The resulting material was studied using scanning electron microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy and thermogravimetry. A mechanism for the chitin-POSS interaction after exposure to these solvothermal conditions is proposed and discussed.

Expression of the AcrAB Components of the AcrAB-TolC Multidrug Efflux Pump of Yersinia enterocolitica Is Subject to Dual Regulation by OmpR.

OmpR is a transcriptional regulator implicated in the control of various cellular processes and functions in Enterobacteriaceae. This study was undertaken to identify genes comprising the OmpR regulon in the human gastrointestinal pathogen Yersinia enterocolitica. Derivatives of an ompR-negative strain with random transposon insertions creating transcriptional fusions with the reporter gene lacZ were isolated. These were supplied with the wild-type ompR allele in trans and then screened for OmpR-dependent changes in ß-galactosidase activity. Using this strategy, five insertions in genes/operons positively regulated by OmpR and two insertions in genes negatively regulated by this protein were identified. Genetic analysis of one of these fusion strains revealed that the gene acrR, encoding transcriptional repressor AcrR is negatively regulated by OmpR. Differential analysis of membrane proteins by SDS-PAGE followed by mass spectrometry identified the protein AcrB, a component of the AcrAB-TolC multidrug efflux pump, as being positively regulated by OmpR. Analysis of the activity of the acrR and acrAB promoters using gfp fusions confirmed their OmpR-dependent repression and activation, respectively. The identification of putative OmpR-binding sites and electrophoretic mobility shift assays confirmed that this regulator binds specifically to both promoter regions with different affinity. Examination of the activity of the acrR and acrAB promoters after the exposure of cells to different chemicals showed that bile salts can act as an OmpR-independent inducer. Taken together, our findings suggest that OmpR positively controls the expression of the AcrAB-TolC efflux pump involved in the adaptive response of Y. enterocolitica O:9 to different chemical stressors, thus conferring an advantage in particular ecological niches.