Multiple Roles of Component Proteins in Bacterial Multicomponent Monooxygenases: Phenol Hydroxylase and Toluene/o-Xylene Monooxygenase from Pseudomonas sp. OX1.

Phenol hydroxylase (PH) and toluene/o-xylene monooxygenase (ToMO) from Pseudomonas sp. OX1 require three or four protein components to activate dioxygen for the oxidation of aromatic substrates at a carboxylate-bridged diiron center. In this study, we investigated the influence of the hydroxylases, regulatory proteins, and electron-transfer components of these systems on substrate (phenol; NADH) consumption and product (catechol; H(2)O(2)) generation. Single-turnover experiments revealed that only complete systems containing all three or four protein components are capable of oxidizing phenol, a major substrate for both enzymes. Under ideal conditions, the hydroxylated product yield was ∼50% of the diiron centers for both systems, suggesting that these enzymes operate by half-sites reactivity mechanisms. Single-turnover studies indicated that the PH and ToMO electron-transfer components exert regulatory effects on substrate oxidation processes taking place at the hydroxylase actives sites, most likely through allostery. Steady state NADH consumption assays showed that the regulatory proteins facilitate the electron-transfer step in the hydrocarbon oxidation cycle in the absence of phenol. Under these conditions, electron consumption is coupled to H(2)O(2) formation in a hydroxylase-dependent manner. Mechanistic implications of these results are discussed

Chemical risk in hospital settings: Overview on monitoring strategies and international regulatory aspects

Chemical risk in hospital settings is a growing concern that health professionals and supervisory authorities must deal with daily. Exposure to chemical risk is quite different depending on the hospital department involved and might origin from multiple sources, such as the use of sterilizing agents, disinfectants, detergents, solvents, heavy metals, dangerous drugs, and anesthetic gases. Improving prevention procedures and constantly monitoring the presence and level of potentially toxic substances, both in workers (biological monitoring) and in working environments (environmental monitoring), might significantly reduce the risk of exposure and contaminations. The purpose of this article is to present an overview on this subject, which includes the current international regulations, the chemical pollutants to which medical and paramedical personnel are mainly exposed, and the strategies developed to improve safety conditions for all healthcare workers.&nbsp

Environmental and biological monitoring of formaldehyde inside a hospital setting: a combined approach to manage chemical risk in workplaces

Background: The safety of healthcare workers exposed to formaldehyde remains a great matter of concern for healthcare management units. This work aimed at describing the results of a combined monitoring approach (environmental and biological) to manage occupational exposure to formaldehyde in a hospital setting.Design and Methods: Environmental monitoring of working spaces and biological monitoring of urinary formaldehyde in 16 exposed healthcare workers of the Anatomic Pathology Unit of a University Hospital in Southern Italy was performed on a four-year timescale (2016-2019).Results: Values of aero-dispersed formaldehyde identified were on average low; although workers' urinary formaldehyde levels were also minimal, the statistical analysis highlighted a slight weekly accumulation.Conclusions: Our data confirm that both environmental and biological monitoring are important to identify risk situations, in particular when values of hazardous compounds are below the accepted occupational exposure levels

Continuous positive airway pressure therapy in the management of hypercapnic cardiogenic pulmonary edema.

Continuous positive airway pressure (CPAP) therapy or non-invasive ventilation (NIV) represent the first line therapy for acute cardiogenic pulmonary edema (CPE) together with medical therapy. CPAP benefits in acute CPE with normo-hypocapnia are known, but it is not clear whether the use of CPAP is safe in the hypercapnic patients. The aim of this study is to evaluate CPAP efficacy in the treatment of hypercapnic CPE. We enrolled 9 patients admitted to the emergency room with diagnosis of acute CPE based on history, clinical examination, arterial blood gas analysis (ABG) and lung-heart ultrasound examination. We selected patients with hypercapnia (pCO2 >50 mmHg) and bicarbonate levels <30 mEq/L. All patients received medical therapy with furosemide and nitrates and helmet CPAP therapy. All patients received a second and a third ABG, respectively at 30 and 60 min. Primary end-points of the study were respiratory distress resolution, pCO2 reduction, pH improvement, lactates normalization and the no need for non-invasive ventilation or endo-tracheal intubation. All patients showed resolution of respiratory distress with CPAP weaning and shift to Venturi mask with no need for NIV or endo-tracheal intubation. Serial ABG tests showed clear reduction in CO2 levels with improvement of pH and progressive lactate reduction. CPAP therapy can be effective in the treatment of hypercapnic CPE as long as the patients have no signs of chronic hypercapnia on ABG and as long as the diagnosis of heart failure is supported by bedside lung-heart ultrasound examination

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements