Comparative analysis of oxygenator dysfunction in polymethylpentene oxygenators: A pilot study.

INTRODUCTION: Polymethylpentene (PMP) oxygenators serve as the primary oxygenator type utilized for ECMO. With the number of PMP oxygenators available, it has become increasingly important to determine differences among each oxygenator type that can lead to varying metrics of oxygenator dysfunction. METHODS: This study was a retrospective, single-center analysis of adult patients supported on ECMO between December 2020 to December 2021 with varying PMP oxygenators including the Medtronic Nautilus Smart (Minneapolis, MA), the Eurosets AMG PMP (Medolla, Italy) and Getinge Quadrox-iD and the Getinge Cardiohelp HLS Module Advanced System (Gothenberg, Sweden). RESULTS: A total of 19 patients were included in our study. 10 patients (52.6%) were supported with a Medtronic Nautilus Smart oxygenator, 5 patients (26.3%) were supported with an Eurosets AMG PMP Oxygenator, and 4 patients (21.1%) were supported with either a Getinge Quadrox-iD oxygenator or Getinge Cardiohelp HLS system. Patients supported with Eurosets AMG PMP oxygenators experienced higher resistance and lower post-oxygenator PaO2 in comparison to other cohorts (p < .02 and < .002 respectively). There was no difference in measured oxygen transfer between cohorts (p = .667). Two patients, both supported by Eurosets AMG PMP, experienced oxygenator failure (p = .094). CONCLUSION: Radial flow oxygenators are prone to higher resistance and lower post-oxygenator PaO2when compared to transverse flow oxygenators. Future larger multicenter studies are required to fully discern the differences between flow-varying polymethylpentene oxygenators and their appropriate cutoffs for oxygenator dysfunction.

Design and validation of Dolosigranulum pigrum specific PCR primers using the bacterial core genome.

Dolosigranulum pigrum-a lactic acid bacterium that is increasingly recognized as an important member of the nasal microbiome. Currently, there are limited rapid and low-cost options for confirming D. pigrum isolates and detecting D. pigrum in clinical specimens. Here we describe the design and validation of a novel PCR assay targeting D. pigrum that is both sensitive and specific. We designed a PCR assay targeting murJ, a single-copy core species gene identified through the analysis of 21 D. pigrum whole genome sequences. The assay achieved 100% sensitivity and 100% specificity against D. pigrum and diverse bacterial isolates and an overall 91.1% sensitivity and 100% specificity using nasal swabs, detecting D. pigrum at a threshold of 1.0 × 104 D. pigrum 16S rRNA gene copies per swab. This assay adds a reliable and rapid D. pigrum detection tool to the microbiome researcher toolkit investigating the role of generalist and specialist bacteria in the nasal environment.

A High-Fidelity Percutaneous Model Used to Demonstrate ECMO Cannulation.

Medical simulation provides a realistic environment for practitioners to experience a planned clinical event in a controlled educational setting. We established a simulation model composed of synthetic ballistic gelatin that provided an inexpensive high-fidelity model for our extracorporeal membrane oxygenation (ECMO) team members to develop, master, and maintain clinical skills necessary for percutaneous cervical or femoral cannulation. The simulation component includes a cervical torso or femoral percutaneous synthetic gelatin model that is attached to either a static fluid model or to the high-fidelity perfusion simulator. Either model can be accessed with ultrasound guidance, cannulated with appropriately sized cannula, and connected to an in situ ECMO circuit. This article explains how the model is made and connected to the simulator with the purpose of re-creating this high-fidelity experience at any institution.

Structural analysis of α-fetoprotein (AFP)-like peptides with anti-breast-cancer properties.

The abundance of α-fetoprotein (AFP), a natural protein produced by the fetal yolk sac during pregnancy, correlates with lower incidence of estrogen receptor positive (ER+) breast cancer. The pharmacophore region of AFP has been narrowed down to a four amino acid (AA) region in the third domain of the 591 AA peptide. Our computational study focuses on a 4-mer segment consisting of the amino acids threonine-proline-valine-asparagine (TPVN). We have run replica exchange molecular dynamics (REMD) simulations and used 120 configurational snapshots from the total trajectory as starting configurations for quantum chemical calculations. We optimized structures using semiempirical (PM3, PM6, PM6-D2, PM6-H2, PM6-DH+, PM6-DH2) and density functional methods (TPSS, PBE0, M06-2X). By comparing the accuracy of these methods against RI-MP2 benchmarks, we devised a protocol for calculating the lowest energy conformers of these peptides accurately and efficiently. This protocol screens out high-energy conformers using lower levels of theory and outlines a general method for predicting small peptide structures.