Patient satisfaction after distal upper limb surgery under WALANT versus axillary block: A propensity-matched comparative cohort study.

Distal upper limb surgery is performed under WALANT (Wide Awake Local Anesthesia No Tourniquet) in many outpatient centers because the benefits are numerous: simple, low-cost technique, with fast turnover and short length of stay. In view of a paucity of data concerning patient satisfaction, this non-randomized cohort study was designed to compare EVAN-LR anesthesia satisfaction questionnaire results (information, pain, expectation, attention, discomfort: 0-100 points) between patients receiving WALANT or axillary nerve block (AxB). After IRB approval, patients (>18 years, stable ASA 1-3) scheduled for outpatient distal upper limb surgery were prospectively enrolled in the two groups. At discharge, patients in both groups received standard information on postoperative recovery and care, with a multimodal analgesic regime (acetaminophen and ketoprofen for 5 days). The primary endpoint was EVAN-LR score before discharge. Secondary endpoints were pain relief and side-effects over a 7-day period. Results were recorded as median and 25-75% interquartile range. Propensity-score-matched analysis was performed. Over the study period, from October 2019 to November 2020, 183 patients were included; 48 WALANT patients were propensity-score matched to 48 AxB patients. Pre-procedural APAIS anxiety score was lower in the WALANT than the AxB group: 9 (IQR, 6-12) vs 12 (IQR, 8-14) (p = 0.01). EVAN-LR scores were similar between the WALANT (78 [72-82]) and the AxB group (73 [67-80]). Incidences of paresthesia and of pain (NRS pain score, opioid rescue) were similar. WALANT patients had shorter length of stay: 135 (110-175) min vs 170 (110-250) min (p = 0.01). The present study demonstrated that WALANT was associated with a high level of patient satisfaction. For clinical relevance and quality of care, WALANT should be proposed in first line for distal limb surgery.

Cnidarian Primary Cell Culture as a Tool to Investigate the Effect of Thermal Stress at Cellular Level.

In the context of global change, symbiotic cnidarians are largely affected by seawater temperature elevation leading to symbiosis breakdown. This process, also called bleaching, is triggered by the dysfunction of the symbiont photosystems causing an oxidative stress and cell death to both symbiont and host cells. In our study, we wanted to elucidate the intrinsic capacity of isolated animal cells to deal with thermal stress in the absence of symbiont. In that aim, we have characterized an animal primary cell culture form regenerating tentacles of the temperate sea anemone Anemonia viridis. We first compared the potential of whole tissue tentacle or separated epidermal or gastrodermal monolayers as tissue sources to settle animal cell cultures. Interestingly, only isolated cells extracted from whole tentacles allowed establishing a viable and proliferative primary cell culture throughout 31 days. The analysis of the expression of tissue-specific and pluripotency markers defined cultivated cells as differentiated cells with gastrodermal origin. The characterization of the animal primary cell culture allowed us to submit the obtained gastrodermal cells to hyperthermal stress (+ 5 and + 8 °C) during 1 and 7 days. Though cell viability was not affected at both hyperthermal stress conditions, cell growth drastically decreased. In addition, only a + 8 °C hyperthermia induced a transient increase of antioxidant defences at 1 day but no ubiquitin or carbonylation protein damages. These results demonstrated an intrinsic resistance of cnidarian gastrodermal cells to hyperthermal stress and then confirmed the role of symbionts in the hyperthermia sensitivity leading to bleaching.

Electronic characterization of silicon intercalated chevron graphene nanoribbons on Au(111).

Electronic and thermal properties of chevron-type graphene nanoribbons can be widely tuned, making them interesting candidates for electronic and thermoelectric applications. Here, we use post-growth silicon intercalation to unambiguously access nanoribbons' energy position of their electronic frontier states. These are otherwise obscured by substrate effects when investigated directly on the growth substrate. In agreement with first-principles calculations we find a band gap of 2.4 eV.

Carbon kagome lattice and orbital-frustration-induced metal-insulator transition for optoelectronics.

A three-dimensional elemental carbon kagome lattice, made of only fourfold-coordinated carbon atoms, is proposed based on first-principles calculations. Despite the existence of 60° bond angles in the triangle rings, widely perceived to be energetically unfavorable, the carbon kagome lattice is found to display exceptional stability comparable to that of C(60). The system allows us to study the effects of triangular frustration on the electronic properties of realistic solids, and it demonstrates a metal-insulator transition from that of graphene to a direct gap semiconductor in the visible blue region. By minimizing s-p orbital hybridization, which is an intrinsic property of carbon, not only the band edge states become nearly purely frustrated p states, but also the band structure is qualitatively different from any known bulk elemental semiconductors. For example, the optical properties are similar to those of direct-gap semiconductors GaN and ZnO, whereas the effective masses are comparable to or smaller than those of Si.

Self-organized and cu-coordinated surface linear polymerization.

We demonstrate a controllable surface-coordinated linear polymerization of long-chain poly(phenylacetylenyl)s that are self-organized into a "circuit-board" pattern on a Cu(100) surface. Scanning tunneling microscopy/spectroscopy (STM/S) corroborated by ab initio calculations, reveals the atomistic details of the molecular structure, and provides a clear signature of electronic and vibrational properties of the poly(phenylacetylene)s chains. Notably, the polymerization reaction is confined epitaxially to the copper lattice, despite a large strain along the polymerized chain that subsequently renders it metallic. Polymerization and depolymerization reactions can be controlled locally at the nanoscale by using a charged metal tip. This control demonstrates the possibility of precisely accessing and controlling conjugated chain-growth polymerization at low temperature. This finding may lead to the bottom-up design and realization of sophisticated architectures for molecular nano-devices.

Topographic and spectroscopic characterization of electronic edge states in CVD grown graphene nanoribbons.

We used scanning tunneling microscopy and spectroscopy (STM/S) techniques to analyze the relationships between the edge shapes and the electronic structures in as-grown chemical vapor deposition (CVD) graphene nanoribbons (GNRs). A rich variety of single-layered graphene nanoribbons exhibiting a width of several to 100 nm and up to 1 µm long were studied. High-resolution STM images highlight highly crystalline nanoribbon structures with well-defined and clean edges. Theoretical calculations indicate clear spin-split edge states induced by electron-electron Coulomb repulsion. The edge defects can significantly modify these edge states, and different edge structures for both sides of a single ribbon produce asymmetric electronic edge states, which reflect the more realistic features of CVD grown GNRs. Three structural models are proposed and analyzed to explain the observations. By comparing the models with an atomic resolution image at the edge, a pristine (2,1) structure was ruled out in favor of a reconstructed edge structure composed of 5-7 member rings, showing a better match with experimental results, and thereby suggesting the possibility of a defective morphology at the edge of CVD grown nanoribbons.

Electronic properties of two-dimensional covalent organic frameworks.

The electronic properties of a number of two-dimensional covalent organic frameworks are studied using a combination of density functional theory and quasiparticle theory calculations. The effect of composition and system size on the electronic band gap is systematically considered for a series of systems, using van der Waals corrected density functional theory calculations to determine the effect of a graphene substrate on deposited covalent frameworks. We predict that covalent organic frameworks' (COFs') electronic properties, such as their band gap can be fine tuned by appropriate modifications of their structures, specifically by increasing organic chain-links in the framework. The effect of strain on the electronic properties is also studied. The graphene substrate is shown to not significantly alter the properties of COFs, thereby indicating the robustness of COFs' intrinsic properties for practical applications.

Controlling edge morphology in graphene layers using electron irradiation: from sharp atomic edges to coalesced layers forming loops.

Recent experimental reports indicate that Joule heating can atomically sharpen the edges of chemical vapor deposition grown graphitic nanoribbons. The absence or presence of loops between adjacent layers in the annealed materials is the topic of a growing debate that this Letter aims to put to rest. We offer a rationale explaining why loops do form if Joule heating is used alone, and why adjacent nanoribbon layers do not coalesce when Joule heating is applied after high-energy electrons first irradiate the sample. Our work, based on large-scale quantum molecular dynamics and electronic-transport calculations, shows that vacancies on adjacent graphene sheets, created by electron irradiation, inhibit the formation of edge loops.

Step-by-step growth of epitaxially aligned polythiophene by surface-confined reaction.

One of the great challenges in surface chemistry is to assemble aromatic building blocks into ordered structures that are mechanically robust and electronically interlinked--i.e., are held together by covalent bonds. We demonstrate the surface-confined growth of ordered arrays of poly(3,4-ethylenedioxythiophene) (PEDOT) chains, by using the substrate (the 110 facet of copper) simultaneously as template and catalyst for polymerization. Copper acts as promoter for the Ullmann coupling reaction, whereas the inherent anisotropy of the fcc 110 facet confines growth to a single dimension. High resolution scanning tunneling microscopy performed under ultrahigh vacuum conditions allows us to simultaneously image PEDOT oligomers and the copper lattice with atomic resolution. Density functional theory calculations confirm an unexpected adsorption geometry of the PEDOT oligomers, which stand on the sulfur atom of the thiophene ring rather than lying flat. This polymerization approach can be extended to many other halogen-terminated molecules to produce epitaxially aligned conjugated polymers. Such systems might be of central importance to develop future electronic and optoelectronic devices with high quality active materials, besides representing model systems for basic science investigations.

Synthesis, electronic structure, and Raman scattering of phosphorus-doped single-wall carbon nanotubes.

Substitutional phosphorus doping in single-wall carbon nanotubes (SWNTs) is investigated by density functional theory and resonance Raman spectroscopy. Electronic structure calculations predict charge localization on the phosphorus atom, generating nondispersive valence and conduction bands close to the Fermi level. Besides confirming sustitutional doping, accurate analysis of electron and phonon renormalization effects in the double-resonance Raman process elucidates the different nature of the phosphorus donor doping (localized) when compared to nitrogen substitutional doping (nonlocalized) in SWNTs.

Covalent 2D and 3D networks from 1D nanostructures: designing new materials.

We show extensive theoretical studies related to the generation and characterization of 2D and 3D ordered networks using 1D units that are connected covalently. We experimentally created multi-terminal junctions containing 1D carbon blocks in order to study the most common morphologies and branched structures that could be used in the theoretical design of network models. We found that the mechanical and electronic characteristics of ordered networks based on carbon nanotubes (ON-CNTs) are dominated by their specific super-architecture (hexagonal, cubic, square, and diamond-type). We show that charges follow specific paths through the nodes of the multi-terminal systems, which could result in complex integrated nanoelectronic circuits. The 3D architectures reveal their ability to support extremely high unidirectional stress when their mechanical properties are studied. In addition, these networks are shown to perform better than standard carbon aerogels because of their low mass densities, continuous porosities, and high surface areas.

Surface reconstructions of TiO2(110) driven by suboxides.

Scanning tunneling microscopy and density functional theory are used to develop a new structural model for surface reconstructions driven by Ti interstitials on TiO2(110). Ti interstitials form the edge- or face-sharing octahedra that serve as building blocks for (1 x 1) reconstruction. Thus, contrary to conventional wisdom, the 1 x 1 periodicity is insufficient to establish the correct surface stoichiometry. Furthermore, in our structural and compositional model the reversible oxidation or reduction between (1 x 1) and (1 x 2) is entirely achieved by transfer of the added rows.

Structure of aggregating kappa-carrageenan fractions studied by light scattering.

We have studied kappa-carrageenan fractions with varying molar mass, obtained by sonication, using static and dynamic light scattering and polarimetry. The samples were characterised in 0.1 M NaCl and 0.1 M NaI, i.e. in the coil and helix conformation, respectively. We find that the molar mass and size of the untreated sample are the same in the coil and helix conformation. For the sonicated samples, we find larger average molar masses and sizes in the helix conformation. The critical temperature, T(c), below which the coil-helix transition sets in, decreases with decreasing molar mass. Aggregation is induced by lowering the temperature in the presence of 0.01 M KCl, which leads to the formation of locally rigid bundles of kappa-carrageenan chains. The thickness of the bundles increases slowly with time and we have not observed stabilisation, even after 24 h at 10 degrees C below T(c). The local structure of the aggregates is the same for all fractions, but at a given temperature, the rate of aggregation decreases with decreasing molar mass.

Expression and induction of CYP1A1/1A2, CYP2A6 and CYP3A4 in primary cultures of human hepatocytes: a 10-year follow-up.

1. The aims were to refine experimental conditions (using 76 human hepatocyte preparations) in terms of the selection of enzyme inducers and their optimal concentration, the treatment duration with inducers and the choice of specific cytochrome P450 isoform(s) probes to optimize the use of primary hepatocytes for predicting the potential induction by new chemical entities of cytochrome P450 isoforms in vivo in man. 2. In the absence of any inducer, basal cytochrome P450 isoform(s)-mediated activities decreased to 20% of their initial activity (end of the seeding period) by 72-96 h. In contrast, UGT-dependent enzyme activities remained at a constant level (+/- 20%) up to the fifth day of culture. 3. Beta-naphthoflavone, at an optimal concentration of 50 microM and after a 3-day treatment, specifically and potently induced 7-ethoxyresorufin (10.4 +/- 10.4-fold, n = 74) and phenacetin (6.6 +/- 6.4-fold, n = 60) O-deethylation processes, markers for CYP1A1 and CYP1A2 isoforms respectively. Only a 2-fold increase was noted following treatment with 2 mM phenobarbitone, whereas dexamethasone and rifampicin had no effect at all. 4. A 3-day treatment of human hepatocytes with 50 microM dexamethasone was associated with a major induction of both coumarin 7-hydroxylation (9.4 +/- 11.4-fold, n = 49) and nifedipine dehydrogenation (4.7 +/- 3.8-fold, n = 61), markers for CYP2A6 and CYP3A4 respectively. Phenobarbitone, however, exhibited a broad but moderate inducing effect on 7-ethoxyresorufin (2.2 +/- 1.5-fold, n = 55) and phenacetin (1.7 +/- 0.9-fold, n = 54) O-deethylation, coumarin 7-hydroxylation (3.9 +/- 9.2-fold, n = 50) and nifedipine dehydrogenation (2.1 +/- 2.0-fold, n = 47). 5. Km obtained for the different cytochrome P450 isoform substrates in untreated hepatocytes were in the same range of magnitude that those determined on human hepatic microsomal fractions. Enzyme induction processes were characterized by a large increase in apparent Vmax whereas apparent Km were not affected. 6. These studies demonstrate that human hepatocytes in primary culture can respond specifically and quantitatively to model inducers. This in vitro system offers a useful approach to study the regulation of human hepatic biotransformation activities and should facilitate the demand for a reproducible method for addressing cytochrome P450 induction.

Role of cytochrome P-4502C9 in irbesartan oxidation by human liver microsomes.

The oxidative metabolism of irbesartan, a new nonpeptide angiotensin II receptor antagonist, was investigated on 12 human fully characterized hepatic microsomes and purified cytochrome P-450 (CYP) isoforms. After incubation of microsomes with irbesartan and NADPH, four main hydroxy metabolites were formed, as confirmed by liquid chromatography-mass spectrometry analysis. Irbesartan oxidation follows Michaelis-Menten kinetics, consistent with the involvement of a single CYP isoform in these hydroxylation processes. Only a low interindividual variability (2-fold difference) was observed in drug oxidation, even in preparations lacking CYP2D6. Km and Vmax for irbesartan oxidation were 54 +/- 6.5 microM and 0.62 +/- 0.18 nmol/min/mg, respectively. Irbesartan oxidation correlated (r2 = 0. 769) with tolbutamide (CYP2C9 substrate) 4-methyl-hydroxylation. Oxidation of irbesartan was markedly inhibited by sulfaphenazole (CYP2C9 inhibitor), but not by any of several other CYP inhibitors. In the same manner, both tolbutamide and warfarin (CYP2C9 substrates), were competitive-type inhibitors of irbesartan oxidation with Ki values of 500 and 30 microM, respectively. Moreover, irbesartan was a competitive-type inhibitor of tolbutamide 4-methylhydroxylation (Ki = 317 microM). Nifedipine also potentially decreased irbesartan oxidation, whereas neither ketoconazole and triacetyloleandomycin (CYP3A inhibitors), nor diltiazem and verapamil, (CYP3A4 substrates), exhibited an inhibitory effect. Additional studies demonstrated that nifedipine was an inhibitor of irbesartan (Ki = 20 microM) and tolbutamide oxidation processes, whereas irbesartan had no effect at all on nifedipine dehydrogenation. Enzyme kinetics suggest that nifedipine is a noncompetitive-type inhibitor of CYP2C9-mediated catalytic activities. Finally, only microsomes containing recombinant human liver CYP2C9 were capable of oxidizing irbesartan. These results provide evidence that CYP2C9 plays a major role in irbesartan oxidation.

Correlation between oral drug absorption in humans, and apparent drug permeability in TC-7 cells, a human epithelial intestinal cell line: comparison with the parental Caco-2 cell line.

PURPOSE: To determine and compare the relationship between in vivo oral absorption in humans and the apparent permeability coefficients (Papp) obtained in vitro on two human intestinal epithelial cell lines, the parental Caco-2 and the TC-7 clone. METHODS: Both cell lines were grown for 5-35 days on tissue culture-treated inserts. Cell monolayers were analysed for their morphology by transmission electron micrography, and for their integrity with respect to transepithelial electrical resistance, mannitol and PEG-4000 transport, and cyclosporin efflux. Papp were determined for 20 compounds exhibiting large differences in chemical structure, molecular weight, transport mechanisms, and percentage of absorption in humans. RESULTS: The TC-7 clone exhibits morphological characteristics similar to those of the parental Caco-2 cell line, concerning apical brush border, microvilli, tight junctions and polarisation of the cell line. The TC-7 clone however appeared more homogenous in terms of cell size. Both cell lines achieved a similar monolayer integrity towards mannitol and PEG-4000. Monolayer integrity was achieved earlier for the TC-7 clone, mainly due to its shorter doubling time, i.e. 26 versus 30 hours for parental Caco-2 cells. When using cyclosporin A as a P-glycoprotein substrate, active efflux was lower in the TC-7 clone than in the parental Caco-2 cells. The Papp and mechanisms of transport (paracellular or transcellular routes, passive diffusion and active transport) were determined for 20 drugs. A relationship was established between the in vivo oral absorption in humans and Papp values, allowing to determine a threshold value for Papp of 2 10(-6) cm/sec, above for which a 100% oral absorption could be expected in humans. Both correlation curves obtained with the two cell types, were almost completely superimposable. These studies also confirmed that the dipeptide transporter is underexpressed in both cell lines. CONCLUSIONS: On the basis of morphological parameters, biochemical activity and drug transport characteristics, the TC-7 clone appeared to be a valuable alternative to the use of parental Caco-2 cells for drug absorption studies.

Cytochrome P450 isoform inhibitors as a tool for the investigation of metabolic reactions catalyzed by human liver microsomes.

Cytochrome P450 chemical inhibitors are widely used to define the role of individual cytochrome P450 isozyme(s) in a metabolism process. In this study, cytochrome P450 isoform-dependent reactions were investigated on our human liver microsomes bank (n = 34) and characterized for both KM and VMAX values (n > or = 3). These metabolic reactions were: 7-ethoxyresorufin O-deethylation (CYP1A1), phenacetin O-deethylation (CYP1A2), coumarin 7-hydroxylation (CYP2A6), tolbutamide 4-methylhydroxylation (CYP2C9), dextromethorphan O-demethylation (CYP2D6), aniline 4-hydroxylation (CYP2E1) and nifedipine dehydrogenation (CYP3A4). Literature data-based specific inhibitors were selected and characterized for both their inhibitory constant (Ki) and the inhibition-type toward their specific substrate. Results were as follows: alpha-naphthoflavone (CYP1A1; mixed-type interaction with a Ki = 0.01 microM), furafylline (CYP1A2; competitive-type interaction with a Ki = 3 microM when microsomes were incubated with both furafylline and phenacetin; noncompetitive-type interaction with a Ki = 0.6 microM when microsomes were preincubated with furafylline and NADPH), pilocarpine (CYP2A6; competitive-type interaction with a Ki = 4 microM), sulfaphenazole (CYP2C9; competitive-type interaction with a Ki = 0.3 microM), quinidine (CYP2D6; competitive-type interaction with a Ki = 0.4 microM, diallyldisulfide (CYP2E1; noncompetitive-type interaction with a Ki = 150 microM on an aniline concentration range of 10-60 microM; competitive-type interaction with a Ki = 100 microM on an aniline concentration range of 80-2000 microM) and ketoconazole (CYP3A4; mixed-type interaction with a Ki = 0.015 microM). Once the inhibitors' potency was determined, the selective effects of these inhibitors were evaluated after incubation of human hepatic microsomes with isoform-selective substrates in the presence of the different chemical inhibitors. Up to 10 times the Ki value toward the isoform-selective probe, pilocarpine, sulfaphenazole, quinidine and ketoconazole exhibited potent inhibitory and specific effects. alpha-Naphthoflavone and furafylline both inhibited phenacetin and 7-ethoxyresorufin O-deethylation processes, a consequence of the absence of CYP1A1 in noninduced human liver. Diallyldisulfide exhibited broad and nonspecific inhibitory effects. When used in their "window of selectivity," ie., up to 10-fold the Ki value, most chemical inhibitors powerfully and specifically inhibited cytochrome P450 isoform-specific reactions when analyzed at their KM values.

The human intestinal epithelial cell line Caco-2; pharmacological and pharmacokinetic applications.

The gastrointestinal tract remains the most popular and acceptable route of administration for drugs. It offers the great advantage of convenience and many compounds are well absorbed and thereby provide acceptable plasma concentration-time profiles. Currently there is considerable interest from the pharmaceutical industry in development of cell culture systems that would mimic the intestinal mucosa in order to evaluate strategies for investigating and/or enhancing drug absorption. The intestinal epithelial cells of primary interest, from the standpoint of drug absorption and metabolism, are the villus cells, which are fully differentiated cells. An in vitro cell culture system consisting of a monolayer of viable, polarized and fully differentiated villus cells, similar to that found in the small intestine, would be a valuable tool in the study of drug and nutrient transport and metabolism. The Caco-2 cell line, which exhibits a well-differentiated brush border on the apical surface and tight junctions, and expresses typical small-intestinal microvillus hydrolases and nutrient transporters, has proven to be the most popular in vitro model (a) to rapidly assess the cellular permeability of potential drug candidates, (b) to elucidate pathways of drug transport (e.g., passive versus carrier mediated), (c) to assess formulation strategies designed to enhance membrane permeability, (d) to determine the optimal physicochemical characteristics for passive diffusion of drugs, and (e) to assess potential toxic effects of drug candidates or formulation components on this biological barrier. Since differentiated Caco-2 cells express various cytochrome P450 isoforms and phase II enzymes such as UDP-glucuronosyltransferases, sulfotransferases and glutathione-S-transferases, this model could also allow the study of presystemic drug metabolism.