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Noninvasive positive-pressure ventilation (NIPPV) is widely used to treat acute respiratory failure, the goal being to avoid exposing patients to the morbidity associated with tracheal intubation. NIPPV may reduce the rates of intubation, morbidity, and mortality in selected patient subgroups. Although time-consuming for physicians and nurses, NIPPV is fairly easy to use, and few severe complications have been reported. Esophageal perforation is a well-recognized complication of tracheal intubation but has not been described in association with NIPPV. We report a case of fatal esophageal perforation associated with NIPPV after a surgical procedure. [ABSTRACT FROM AUTHOR]

Quinones are among the most important components in natural organic matter (NOM) for redox reactions; however, no quinones in complex environmental media have been identified. To aid the identification of quinone-containing molecules in ultracomplex environmental samples, we developed a chemical tagging method that makes use of a Michael addition reaction between quinones and thiols (-SH) in cysteine (Cys) and cysteine-contained peptides (CCP). After the tagging, candidates of quinones in representative aqueous environmental samples (water extractions of biochar) were identified through high-resolution mass spectrometry (HRMS) analysis. The MS and UV spectra analysis showed rapid reactions between Cys/CCP and model quinones with β-carbon from the same benzene ring available for Michael addition. The tagging efficiency was not influenced by other co-occurring nonquinone representative compounds, including caffeic acid, cinnamic acid, and coumaric acid. Cys and CCP were used to tag quinones in water extractions of biochars, and possible candidates of quinones (20 and 53 based on tagging with Cys and CCP, respectively) were identified based on the HRMS features for products of reactions with Cys/CCP. This study has successfully demonstrated that such a Michael addition reaction can be used to tag quinones in complex environmental media and potentially determine their identities. The method will enable an in-depth understanding of the redox chemistry of NOM and its critical chemical compositions and structures.

Understanding the chemical nature of soil organic carbon (SOC) with great potential to bind iron (Fe) minerals is critical for predicting the stability of SOC. Organic ligands of Fe are among the top candidates for SOCs able to strongly sorb on Fe minerals, but most of them are still molecularly uncharacterized. To shed insights into the chemical nature of organic ligands in soil and their fate, this study developed a protocol for identifying organic ligands using ultrahigh-performance liquid chromatography-high-resolution tandem mass spectrometry (UHPLC-HRMS/MS) and metabolomic tools. The protocol was used for investigating the Fe complexes formed by model compounds of lignin-derived organic ligands, namely, caffeic acid (CA), p -coumaric acid (CMA), vanillin (VNL), and cinnamic acid (CNA). Isotopologue analysis of 54/56 Fe was used to screen out the potential UHPLC-HRMS ( m / z ) features for complexes formed between organic ligands and Fe, with multiple features captured for CA, CMA, VNL, and CNA when 35/37 Cl isotopologue analysis was used as supplementary evidence for the complexes with Cl. MS/MS spectra, fragment analysis, and structure prediction with SIRIUS were used to annotate the structures of mono/bidentate mono/biligand complexes. The analysis determined the structures of monodentate and bidentate complexes of FeL x Cl y (L: organic ligand, x = 1-4, y = 0-3) formed by model compounds. The protocol developed in this study can be used to identify unknown organic ligands occurring in complex environmental samples and shed light on the molecular-level processes governing the stability of the SOC.

Interactions between phytoplankton and heterotrophic bacteria fundamentally shape marine ecosystems by controlling primary production, structuring marine food webs, mediating carbon export, and influencing global climate. Phytoplankton-bacterium interactions are facilitated by secreted compounds; however, linking these chemical signals, their mechanisms of action, and their resultant ecological consequences remains a fundamental challenge. The bacterial quorum-sensing signal 2-heptyl-4-quinolone (HHQ) induces immediate, yet reversible, cellular stasis (no cell division or mortality) in the coccolithophore Emiliania huxleyi ; however, the mechanism responsible remains unknown. Using transcriptomic and proteomic approaches in combination with diagnostic biochemical and fluorescent cell-based assays, we show that HHQ exposure leads to prolonged S-phase arrest in phytoplankton coincident with the accumulation of DNA damage and a lack of repair despite the induction of the DNA damage response (DDR). While this effect is reversible, HHQ-exposed phytoplankton were also protected from viral mortality, ascribing a new role of quorum-sensing signals in regulating multitrophic interactions. Furthermore, our data demonstrate that in situ measurements of HHQ coincide with areas of enhanced micro- and nanoplankton biomass. Our results suggest bacterial communication signals as emerging players that may be one of the contributing factors that help structure complex microbial communities throughout the ocean. IMPORTANCE Bacteria and phytoplankton form close associations in the ocean that are driven by the exchange of chemical compounds. The bacterial signal 2-heptyl-4-quinolone (HHQ) slows phytoplankton growth; however, the mechanism responsible remains unknown. Here, we show that HHQ exposure leads to the accumulation of DNA damage in phytoplankton and prevents its repair. While this effect is reversible, HHQ-exposed phytoplankton are also relieved of viral mortality, elevating the ecological consequences of this complex interaction. Further results indicate that HHQ may target phytoplankton proteins involved in nucleotide biosynthesis and DNA repair, both of which are crucial targets for viral success. Our results support microbial cues as emerging players in marine ecosystems, providing a new mechanistic framework for how bacterial communication signals mediate interspecies and interkingdom behaviors., (Copyright © 2021 Pollara et al.)

We report a novel technical approach for subcritical fluid extraction (SFE) for organic matter characterization in complex matrices such as soil. The custom platform combines on-line SFE with micro-solid phase extraction, nano liquid chromatography (LC), electrospray ionization and Fourier transform mass spectrometry (SFE-LC-FTMS). We demonstrated the utility of SFE-LC-FTMS, including results from both Orbitrap and FTICR MS, for analysis of complex mixtures of organic compounds in a solid matrix by characterizing soil organic matter in peat, a high-carbon soil. For example, in a single experiment, >6000 molecular formulas can be assigned based upon FTICR MS data from 1-50 μL of soil samples (roughly 1-50 mg of soil, dependent on soil density), nearly twice that typically obtained from direct infusion liquid solvent extraction (LSE) from an order of magnitude larger volume of the same soil. The detected species consisted predominately of lipid-like, lignin-like and protein-like compounds, based on their O/C and H/C ratios, with predominantly CHO and CHONP molecular compositions. These results clearly demonstrate that SFE has the potential to effectively extract a variety of molecular species and could become an important member of a suite of extraction methods for studying SOM and other natural organic matter. This is especially true when comprehensive coverage, minimal sample volumes, and high sensitivity are required, or when the presence of organic solvent residue in residual soil is problematic. The SFE based extraction protocol could potentially enable spatially resolved characterization of organic matter in soil with a resolution of ∼1 mm3 to facilitate studies probing the spatial heterogeneity of soil.

The use of enterococci as the primary fecal indicator bacteria (FIB) for the determination of recreational water safety has been questioned, particularly in sub/tropical marine waters without known point sources of sewage. Alternative FIB (such as the Bacteroidales group) and alternative measurement methods (such as rapid molecular testing) have been proposed to supplement or replace current marine water quality testing methods which require culturing enterococci. Moreover, environmental parameters have also been proposed to supplement current monitoring programs. The objective of this study was to evaluate the health risks to humans from exposure to subtropical recreational marine waters with no known point source. The study reported symptoms between one set of human subjects randomly assigned to marine water exposure with intensive environmental monitoring compared with other subjects who did not have exposure. In addition, illness outcomes among the exposed bathers were compared to levels of traditional and alternative FIB (as measured by culture-based and molecular-based methods), and compared to easily measured environmental parameters. Results demonstrated an increase in self-reported gastrointestinal, respiratory and skin illnesses among bathers vs. non-bathers. Among the bathers, a dose-response relationship by logistic regression modeling was observed for skin illness, where illness was positively related to enterococci enumeration by membrane filtration (odds ratio = 1.46 [95% confidence interval = 0.97-2.21] per increasing log10 unit of enterococci exposure) and positively related to 24 h antecedent rain fall (1.04 [1.01-1.07] per increasing millimeters of rain). Acute febrile respiratory illness was inversely related to water temperature (0.74 [0.56-0.98] per increasing degree of water temperature). There were no significant dose-response relationships between report of human illness and any of the other FIB or environmental measures. Therefore, for non-point source subtropical recreational marine waters, this study suggests that humans may be at increased risk of reported illness, and that the currently recommended and investigational FIB may not track gastrointestinal illness under these conditions; the relationship between other human illness and environmental measures is less clear., (Published by Elsevier Ltd.)

Objective: The aim of this study was to evaluate the accuracy of the BNP as a marker of acute cor pulmonale in patients with ARDS., Study Design: Prospective clinical trial., Patients and Methods: At day 2 or 3 after the onset of the ARDS, an echocardiography was performed. Patients with left ventricular dysfunction were excluded. Right ventricular area (RVA) and RVA/LVA ratio were measured. ACP was defined as RVA/LVA > 0.6 associated with septal dyskinesia. Simultaneously, 5 ml of blood was collected for BNP measurement., Results: 26 patients were studied. BNP levels were higher in 10 patients with ACP: 585.5 [189-4830] vs 145.5 [36.5-346] pg/ml (P=0.01) but in those with creatinine clearance < 90 ml/min: 602 [331-3530] vs 125 [39-189] pg/ml (P=0.007). BNP was correlated with RVA (r=0.5; p=0.01), RVA/LVA ratio (r=0.61; p=0.001), sPAP (r=0.58; p=0.002) and with age, cardiac index and creatinine clearance (r=0.61; p=0.001). In multivariate analysis, BNP was only correlated with creatinine clearance (p=0.03), and RVA (p=0.06)., Conclusion: In ARDS patients without left ventricular dysfunction, BNP level is more elevated in patients with acute cor pulmonale than patients without cor pulmonale.

Objective: A comparison was made between the endogenous carbon monoxide (CO) production in mechanically ventilated critically ill adult patients with, and those without, severe sepsis., Design: Prospective comparative study., Setting: Medical ICU in a community hospital., Patients: Twenty-four patients with severe sepsis of various etiologies and five control patients with varying diagnoses., Intervention: CO concentration was determined with an infrared CO analyzer on exhaled breath collected at the outlet of the ventilator. Endogenous CO production was estimated by the lung CO excretion rate measured at steady state., Measurements and Main Results: : Endogenous CO production was higher in the sepsis group during the first 3 days of treatment in comparison to the control group (10.9+/-5 (SD) microl/kg per h on day 1, 7.8+/-4.9 microl/kg per h on day 2 and 6.9+/-4.7 microl/kg per h on day 3 versus 2.1+/-0.5 microl/kg per h; p<0.01 for each comparison). Survivors of sepsis had a significantly higher endogenous CO production on day 1 compared to non-survivors (14.7+/-5.3 versus 8.5+/-3.3 microl/kg per h; p=0.02)., Conclusion: Endogenous CO production was significantly higher in mechanically ventilated patients suffering from severe sepsis. Further studies are required in order to determine the mechanism(s) and the functional significance of this increase.

Mechanical ventilation through endotracheal prosthesis, suppresses the nose functions and stops elimination of secretions. It is mandatory to heat artificially, humidify insufflated gas and to suction tracheobronchial secretions. Heating humidifiers are very efficient for the first purpose but heat and moisture exchangers, a little less efficient, seem to be a good alternative as they are easiest to use and offer a good bacterial protection. Tracheobronchial suctioning has to be carried out at least each four hours and at the best as soon as adventitious sound are heard in the chest. Suction catheters have to be atraumatic; vacuum has to be between -200 to -400 cm H2O; catheter have not to be pushed further than the carina; suction hypoxemia can be reduced by shortening suction maneuver, by using suction catheter with little diameter, by conducting the suction on mechanical ventilation.