Background: The majority of postoperative patients report moderate to severe pain, possibly related to opioid underdosing or overdosing during surgery. Objective guidance of opioid dosing using the Nociception Level (NOL) index, a multiparameter artificial intelligence-driven index designed to monitor nociception during surgery, may lead to a more appropriate analgesic regimen, with effects beyond surgery. We tested whether NOL-guided opioid dosing during general anaesthesia results in less postoperative pain. Methods: In this two-centre RCT, 50 patients undergoing abdominal surgery under fentanyl/sevoflurane anaesthesia were randomised to NOL-guided fentanyl dosing or standard care in which fentanyl dosing was based on haemodynamics. The primary endpoint of the study was postoperative pain assessed in the PACU. Results: Median postoperative pain scores were 3.2 (inter-quartile range 1.3e4.3) and 4.8 (3.0e5.3) in NOL-guided and standard care groups, respectively (P¼0.006). Postoperative morphine consumption (standard deviation) was 0.06 (0.07) mg kg À1 (NOL-guided group) and 0.09 (0.09) mg kg À1 (control group; P¼0.204). During surgery, fentanyl dosing was not different between groups (NOL-guided group: 6.4 [4.2] mg kg À1 vs standard care: 6.0 [2.2] mg kg À1 , P¼0.749), although the variation between patients was greater in the NOL-guided group (% coefficient of variation 66% in the NOL-guided group vs 37% in the standard care group). Conclusions: Despite absence of differences in fentanyl and morphine consumption during and after surgery, a 1.6-point improvement in postoperative pain scores was observed in the NOL-guided group. We attribute this to NOL-driven rather than BP-and HR-driven fentanyl dosing during anaesthesia. Clinical trial registration: www.trialregister.nl under identifier NL7845.

CYP102A1, originating from Bacillus megaterium, is a highly active enzyme which has attracted much attention because of its potential applicability as a biocatalyst for oxidative reactions. Previously we developed drug-metabolizing mutant CYP102A1 M11 by a combination of site-directed and random mutagenesis. CYP102A1 M11 contains eight mutations, when compared with wild-type CYP102A1, and is able to produce human-relevant metabolites of several pharmaceuticals. In this study, active-site residue 87 of drug-metabolizing mutant CYP102A1 M11 was mutated to all possible natural amino acids to investigate its role in substrate selectivity and regioselectivity. With alkoxyresorufins as substrates, large differences in substrate selectivities and coupling efficiencies were found, dependent on the nature of residue 87. For all combinations of alkoxyresorufins and mutants, extremely fast rates of NADPH oxidation were observed (up to 6,000 min−1). However, the coupling efficiencies were extremely low: even for the substrates showing the highest rates of O-dealkylation, coupling efficiencies were lower than 1%. With testosterone as the substrate, all mutants were able to produce three hydroxytestosterone metabolites, although with different activities and with remarkably different product ratios. The results show that the nature of the amino acid at position 87 has a strong effect on activity and regioselectivity in the drug-metabolizing mutant CYP102A1 M11. Because of the wide substrate selectivity of CYP102A1 M11 when compared with wild-type CYP102A1, this panel of mutants will be useful both as biocatalysts for metabolite production and as model proteins for mechanistic studies on the function of P450s in general.

The distribution of linear alkylbenzene sulfonates (LAS) and their biodegradation intermediates (SPC) has been studied at a salt marsh of the Bay of Cadiz. The identification and quantification of LAS and SPC was carried out after solidphase extraction of 250 mL of water samples followed by liquid chromatography with fluorescence, diode array, and ionspray mass spectrometry. The latter procedure permitted the unequivocal confirmation of long-chain SPC, of up to 11 carbon atoms in seawater, and of up to 13 carbon atoms in interstitial water. Some of these compounds have not been described until now in environmental samples. The relative abundance of the SPC found at some of the sampling stations agrees with what would be expected after the occurrence of the first and second β-oxidations of the alkyl chain of the various homologues of commercial LAS. Furthermore, the existence of SPC-C13 in interstitial water proves unequivocally that ω-oxidation occurs in the environment. In general terms, the persistence of longchain SPC is evidence that the biodegradation of LAS is a slow process in a marine environment that is deficient in oxygen and highly contaminated with other organic substrates.

Ion mobility (IM) is now a well-established and fast analytical technique. The IM hardware is constantly being improved, especially in terms of the resolving power. The Drift Tube (DTIMS), the Traveling Wave (TWIMS), and the Trapped Ion Mobility Spectrometry (TIMS) coupled to mass spectrometry are used to determine the Collision Cross-Sections (CCS) of ions. In analytical chemistry, the CCS is approached as a descriptor for ion identification and it is also used in physical chemistry for 3D structure elucidation with computational chemistry support. The CCS is a physical descriptor extracted from the reduced mobility (K) measurements obtainable only from the DTIMS. TWIMS and TIMS routinely require a calibration procedure to convert measured physical quantities (drift time for TWIMS and elution voltage for TIMS) into CCS values. This calibration is a critical step to allow interinstrument comparisons. The previous calibrating substances lead to large prediction bands and introduced rather large uncertainties during the CCS determination. In this paper, we introduce a new IM calibrant (CCS and K) using singly charged sodium adducts of poly(ethylene oxide) monomethyl ether (CHO-PEO-H) for positive ionization in both helium and nitrogen as drift gas. These singly charged calibrating ions make it possible to determine the CCS/K of ions having higher charge states. The fitted calibration plots exhibit larger coverage with less data scattering and significantly improved prediction bands and uncertainties. The reasons for the improved CCS/K accuracy, advantages, and limitations of the calibration procedures are also discussed. A generalized IM calibration strategy is suggested.

Cytochrome P450 BM3 from Bacillus megaterium is a monooxygenase with great potential for biotechnological applications. In this paper, we present engineered drug-metabolizing P450 BM3 mutants as a novel tool for regioselective hydroxylation of steroids at position 16β. In particular, we show that by replacing alanine at position 82 with a tryptophan in P450 BM3 mutants M01 and M11, the selectivity toward 16β-hydroxylation for both testosterone and norethisterone was strongly increased. The A82W mutation led to a ≤42-fold increase in V(max) for 16β-hydroxylation of these steroids. Moreover, this mutation improves the coupling efficiency of the enzyme, which might be explained by a more efficient exclusion of water from the active site. The substrate affinity for testosterone increased at least 9-fold in M11 with tryptophan at position 82. A change in the orientation of testosterone in the M11 A82W mutant as compared to the orientation in M11 was observed by T(1) paramagnetic relaxation nuclear magnetic resonance. Testosterone is oriented in M11 with both the A- and D-ring protons closest to the heme iron. Substituting alanine at position 82 with tryptophan results in increased A-ring proton-iron distances, consistent with the relative decrease in the level of A-ring hydroxylation at position 2β.