Catecholamine-induced acute myocardial stunning after accidental intra-operative noradrenaline bolus.

We report a case of catecholamine-induced acute myocardial stunning that occurred in a six-year-old girl. This was triggered by an accidental noradrenaline injection during general anaesthesia for dental surgery. The clinical course was favourable, although cardiac enzymes and echocardiography were significantly altered. The child was discharged home on the second postoperative day, after complete clinical resolution. We emphasise the need to consider shortening the surgical procedure, and to closely monitor patients following a medication error involving vasopressors even in the absence of symptoms. We highlight the importance of a controlled process for storing, identifying, preparing, and handling medications. The identification of weaknesses in the overall process of drug prescription and administration is of utmost importance.

Culturable and metagenomic approaches of wheat bran and wheat straw phyllosphere's highlight new lignocellulolytic microorganisms.

The phyllosphere, defined as the aerial parts of plants, is one of the most prevalent microbial habitats on earth. The microorganisms present on the phyllosphere can have several interactions with the plant. The phyllosphere represents then a unique niche where microorganisms have evolved through time in that stressful environment and may have acquired the ability to degrade lignocellulosic plant cell walls in order to survive to oligotrophic conditions. The dynamic lignocellulolytic potential of two phyllospheric microbial consortia (wheat straw and wheat bran) has been studied. The microbial diversity rapidly changed between the native phyllospheres and the final degrading microbial consortia after 48 h of culture. Indeed, the initial microbial consortia was dominated by the Ralstonia (35·8%) and Micrococcus (75·2%) genera for the wheat bran and wheat straw whereas they were dominated by Candidatus phytoplasma (59%) and Acinetobacter (31·8%) in the final degrading microbial consortia respectively. Culturable experiments leading to the isolation of several new lignocellulolytic isolates (belonging to Moraxella and Atlantibacter genera) and metagenomic reconstruction of the microbial consortia highlighted the existence of an unpredicted microbial diversity involved in lignocellulose fractionation but also the existence of new pathways in known genera (presence of CE2 for Acinetobacter, several AAs for Pseudomonas and several GHs for Bacillus in different metagenomes-assembled genomes). The phyllosphere from agricultural co-products represents then a new niche as a lignocellulolytic degrading ecosystem.

Enzymatically-synthesized xylo-oligosaccharides laurate esters as surfactants of interest.

Lipase-catalyzed synthesis of xylo-oligosaccharides esters from pure xylobiose, xylotriose and xylotetraose in the presence of vinyl laurate was investigated. The influence of different experimental parameters such as the loading of lipase, the reaction duration or the use of a co-solvent was studied and the reaction conditions were optimized with xylobiose. Under the best conditions, a regioselective esterification occurred to yield a monoester with the acyl chain at the OH-4 of the xylose unit at the non-reducing end. Surface-active properties of these pure xylo-oligosaccharides fatty esters have been evaluated. They display interesting surfactant activities that differ according to the degree of polymerization (DP) of the glycone moiety.

Exploring the aglycone subsite of a GH11 xylanase for the synthesis of xylosides by transglycosylation reactions.

Xylanases Tx-xyn10 and Tx-xyn11 were compared for their transxylosylation abilities in the presence of various acceptors. Tx-xyn10 exhibited a broad specificity for various acceptors, whereas xylanase Tx-xyn11 catalysed transxylosylation reactions only in presence of polyphenolic acceptors. A modelling approach was developed to study the molecular bottlenecks into the active site of the enzyme that could be responsible for this restricted specificity. The glycosyl-enzyme intermediate of Tx-xyn11 was modelled, and a rotamer of the Y78 residue was integrated. In silico mutations of some residues from the (+1) and (+2) subsites were tested for the deglycosylation step in the presence of non-polyphenolic acceptors. The results indicated that the mutant W126A was able to use aliphatic alcohols and benzyl alcohol as acceptors for transxylosylation. Experimental validation was tested by mutating the xylanase Tx-xyn11 at position W126 into alanine. The specific activity and catalytic efficiency of the W126A mutant during the hydrolysis of xylans decreased by 2-fold and 4-fold, respectively, compared to wild-type xylanase. Among tested acceptors, transxylosylation catalysed by mutant W126A was improved with benzyl alcohol leading to a 2-fold higher concentration of benzyl xylobioside, as predicted by in silico mutation. This improved transxylosylation in the presence of benzyl alcohol leading to higher synthesis of benzyl xylobioside could likely be explained by lowest steric hindrance in the aglycone subsite of the mutated xylanase. No secondary hydrolysis of benzyl xylobioside occurred for both wild-type and mutant xylanases. Finally, our results demonstrated that the modelling approach was limited and that accounting for protein dynamics can lead to improved models.

Preparation of new ß-D-xyloside- and ß-D-xylobioside-based ionic liquids through chemical and/or enzymatic reactions.

Several tetraalkylphosphonium and tetraalkylammonium salts containing xyloside- and xylobioside-based anionic moieties have been prepared. Two stereoselective routes have been developed: i) a chemical pathway in four steps from D-xylose, and ii) a chemoenzymatic pathway directly from biomass-derived xylans. These salts displayed interesting properties as ionic liquids. Their structures have been correlated to their thermal properties (melting, glass transition and decomposition temperatures).

Dynamic study of how the bacterial breakdown of plant cell walls allows the reconstitution of efficient hemicellulasic cocktails.

Designing more efficient mixtures of enzymes is necessary to produce molecules of interest from biomass lignocellulosic fractionation. The present study aims to investigate the strategies used by the thermophilic and hemicellulolytic bacterium Thermobacillus xylanilyticus to fractionate wheat bran and wheat straw during its growth. Results demonstrated ratios and levels of hemicellulases produced varied during growth on both biomasses. Xylanase activity was mainly produced during stationary stages of growth whereas esterase and arabinosidase activities were detected earlier. This enzymatic profile is correlated with the expression pattern of genes encoding four hemicellulases (two xylanases, one arabinosidase and one esterase) produced by T. xylanilyticus during growth. Based on identification of the bacterial strategy, the synergistic efficiency of the four hemicellulases during the hydrolysis of both substrates was evaluated. The four hemicellulases worked together with high degree of synergy and released high amounts of xylose, arabinose and phenolic acids from wheat bran and wheat straw.

Novel surface-based methodologies for investigating GH11 xylanase-lignin derivative interactions.

The recalcitrance of lignocellulose to bioprocessing represents the core problem and remains the limiting factor in creating an economy based on lignocellulosic ethanol production. Lignin is responsible for unproductive interactions with enzymes, and understanding how lignin impairs the susceptibility of biomass to enzymatic hydrolysis represents a significant aim in optimising the biological deconstruction of lignocellulose. The objective of this study was to develop methodologies based on surface plasmon resonance (SPR), which provide novel insights into the interactions between xylanase (Tx-xyn11) and phenolic compounds or lignin oligomers. In a first approach, Tx-xyn11 was fixed onto sensor surfaces, and phenolic molecules were applied in the liquid phase. The results demonstrated weak affinity and over-stoichiometric binding, as several phenolic molecules bound to each xylanase molecule. This approach, requiring the use of soluble molecules in the liquid phase, is not applicable to insoluble lignin oligomers, such as the dehydrogenation polymer (DHP). An alternative approach was developed in which a lignin oligomer was fixed onto a sensor surface. Due to their hydrophobic properties, the preparation of stable lignin layers on the sensor surfaces represented a considerable challenge. Among the various chemical and physico-chemical approaches assayed, two approaches (physisorption via the Langmuir-Blodgett technique onto self-assembled monolayer (SAM)-modified gold and covalent coupling to a carboxylated dextran matrix) led to stable lignin layers, which allowed the study of its interactions with Tx-xyn11 in the liquid phase. Our results indicated the presence of weak and non-specific interactions between Tx-xyn11 and DHP.

[Cardiac tamponade by right atrial laceration due to blunt chest trauma in a 3-year-old child]. / Tamponnade cardiaque par plaie de l'oreillette droite liée à un traumatisme fermé du thorax chez une enfant de trois ans.

The case of 3-year-old girl severely injured, as restrained car passenger in a road crash, is reported. She presented with isolated circulatory failure, without specific clinical signs except skin contusions corresponding to seat belt. Because of mediastinum enlargement on systematic chest X-ray, a pericardial effusion was suspected, which was confirmed by echography, rapidly complicated by an acute tamponade without visible cause on CT-scan. The radiological assessment showed a moderate peritoneal haemorrhage related to a splenic injury. A persistent haemodynamic instability required a pericardial puncture, after rapid sequence tracheal intubation of the child, but without clinical improvement, despite fluid bolus, red-blood cell transfusion and epinephrine infusion. The child was rapidly transferred to the cardiac operating room for sternotomy, which showed a right atrial laceration. The injury was repaired, allowing the child to survive without disability. Tamponade due to traumatic cardiac injury is extremely rare in children. The clinical diagnosis is particularly difficult to establish in the context of polytrauma. The classical symptoms of cardiac tamponade are rarely complete. The association of chest injury, isolated circulatory failure and enlargement of mediastinum at chest X-ray should alert the physician. As the severity of these injuries is high, a rapid and multidisciplinary management is required, as well as specific anaesthetics precautions.

Effect of harvesting date on the composition and saccharification of Miscanthus x giganteus.

The chemical composition of the whole aerial biomass and isolated organs of Miscanthus x giganteus was examined for saccharification into fermentable sugars at early and late harvesting dates. Delayed harvest was mainly related to increased amounts of cell wall and ester-linked phenolic acids. Addition of an enzyme cocktail (cellulases, beta-glucosidase and xylanase) resulted in similar enzyme digestibilities at the two harvesting dates, ranging from 11-13% and 8-9% of the cellulose and arabinoxylan, respectively. However, the internodes, leaves and sheaths varied in cell wall content and composition and gave rise to different saccharification yields with internodes being the most recalcitrant organs. Non-cell wall fraction was estimated as the amount of material extracted by neutral detergent solution, and accounted for 23% of the whole aerial biomass harvested at an early date. However, saccharification yields from the miscanthus biomass did not change after soluble fraction removal. An ammonia pretreatment improved enzyme efficiency on early-harvested miscanthus, to a greater extent than on late-harvested biomass. This trend was confirmed for two different years of harvesting.

Combination of ammonia and xylanase pretreatments: impact on enzymatic xylan and cellulose recovery from wheat straw.

Soaking in aqueous ammonia (SSA) and/or xylanase pretreatments were developed on wheat straw. Both pretreatments were conducted at high-solids conditions: 15% and 20%, respectively, for SSA and xylanase pretreatments. SSA pretreatment led to the solubilisation of 38%, 12% and 11% of acid insoluble lignin, xylan and glucan, respectively. In case of xylanase pretreatment, 20% of xylan were removed from native wheat straw. When pretreatments were applied consecutively (SSA and xylanase) on straw, 56% of xylans were hydrolysed and a rapid reduction of media viscosity occurred. The enzymatic hydrolysis of cellulose with cellulases was evaluated from the different combinations of pretreated wheat straw. Cellulose hydrolysis was improved by 2.1, 2.2 and 2.9, respectively, for xylanase, SSA and SSA/xylanase pretreated straw. Xylans from untreated and pretreated wheat straws were also solubilised with cellulases. Chemical analysis of pretreated straw residues in connection with yields of cellulose hydrolysis highlighted the role of phenolic acids, acetyl content and cellulose crystallinity for cellulase efficiency.

A versatile high-resolution x-ray imager (HRXI) for laser-plasma experiments on OMEGA.

A high-resolution x-ray imager (HRXI) devoted to laser-plasma experiments combines two state-of-the-art technologies developed in France: a high-resolution x-ray microscope and a high-speed x-ray streak camera. The resulting streaked imager achieves spatial and temporal resolutions of approximately 5 microm and approximately 10 ps, respectively. The HXRI has recorded enhanced spatial and temporal resolution radiographs of indirectly driven targets on OMEGA. This paper describes the main features of the instrument and details the activation process on OMEGA (particularly the alignment). Recent results obtained on joint CEA/LLE radiographic OMEGA experiments will also be presented.

9 cis,11 trans conjugated linoleic acid (CLA) is synthesised and desaturated into conjugated 18:3 in bovine adipose tissues.

Although endogenous synthesis of conjugated linoleic acid (CLA) in the mammary gland of lactating cows has been already well documented, no study has determined so far as to which tissue and/or organ is involved in CLA synthesis in the growing ruminant except one study showing that CLA synthesis does not occur in ruminant liver. In this context, adipose tissue appears to be a good candidate for endogenous synthesis of CLA in the growing ruminant. The aim of this study was to compare the respective metabolisms of 11trans 18:1 (vaccenic acid, VA) and 9cis,11trans 18:2 (rumenic acid) to that of stearic acid (the preferential substrate of Δ9 desaturase) in adipose tissues (subcutaneous, SC and intermuscular, IM) of six Charolais steers by using the in vitromethod of incubated tissue slices. Samples of SC and IM adipose tissues were incubated at 37°C for 16 h under an atmosphere of 95% O2/5% CO2 in a medium supplemented with 0.75 mM of fatty acid (FA) mixture (representative of circulating non-esterified FA) and 186 µM [1-14C]-18:0 or 58.6 µM [1-14C]-VA or 56 µM [1-14C]-9cis,11trans CLA. Viability of explants was verified by measuring metabolic functions (glucose uptake and glucose-6-phosphate dehydrogenase activity). After 16 h of incubation, FA uptake was similar for all FA (18:0, VA and 9cis,11trans 18:2) in both SC and IM adipose tissues (around 40%). Once in adipose tissue, all FA were preferentially esterified (>80% of cell FA) favouring neutral lipid synthesis (around 90% of esterified FA). Stearic acid was highly (27%) desaturated into oleic acid in SC adipose tissue whereas this desaturation was much lower (6.8%) in IM adipose tissue (P < 0.0001). VA was desaturated into 9cis,11trans CLA at a low extent of about 2.5% to 4.4% in both adipose tissues probably because of a limited affinity of Δ9 desaturase for VA. 9cis,11trans CLA was itself converted by desaturation into 6cis, 9cis,11trans 18:3 at the intensity of 10.8% and 14.5% of cell 9cis,11trans CLA in SC and IM adipose tissues, respectively. In conclusion, bovine adipose tissues of the growing ruminant were especially involved in the endogenous synthesis of CLA from VA and in its desaturation into conjugated derivative, mainly 6cis, 9cis,11trans 18:3, of which biological properties need to be elucidated.

TGFbeta1 effects on functional activity of porcine thyroid cells cultured in suspension.

Thyrotropin (TSH) and transforming growth factor beta 1 (TGFbeta1) have major roles in the regulation of folliculogenesis and differentiation in thyroid cells. Isolated porcine thyroid cells cultured in the presence of TSH on a plastic surface recover a follicular architecture and exhibit normal functional properties. The addition of TGFbeta1 to the culture medium induces important morphological changes and extracellular matrix remodelling. Similarly, thyroid cells lose their ability to organify iodine and their responsiveness to adenylate cyclase. The aim of this study was to analyse the influence of TGFbeta1 on the functional activity of thyrocytes in suspension culture, independent of follicle disruption. In this system, we demonstrate that TGFbeta1 inhibits expression of thyroperoxidase, NADPH oxidase activity, iodine uptake and, consequently, iodine organification. Moreover, TGFbeta1 decreases basal and TSH-stimulated cAMP production and TSH receptor expression. Taken together, these data converge to demonstrate an essential role of TGFbeta1 in the regulation of the thyroid cell function.

Continuous fascia iliaca compartment block in children: a prospective evaluation of plasma bupivacaine concentrations, pain scores, and side effects.

UNLABELLED: We sought to determine the plasma concentrations of bupivacaine and its main metabolite after continuous fascia iliaca compartment (FIC) block in children. Twenty children (9.9 +/- 4 yr, 38 +/- 19 kg) received a continuous FIC block for either postoperative analgesia (n = 16) or femoral shaft fracture (n = 4). A bolus dose of 0.25% bupivacaine (1.56 +/- 0.3 mg/kg) with epinephrine was followed by a continuous administration of 0.1% bupivacaine (0.135 +/- 0.03 mg. kg(-)(1). h(-)(1)) for 48 h. Plasma bupivacaine levels were determined at 24 h and 48 h by using gas liquid chromatography. Heart rate, arterial blood pressure, respiratory rate, side effects, and pain scores were recorded at 4-h intervals during 48 h. No significant differences were found between mean plasma bupivacaine levels at 24 h (0.71 +/- 0.4 microg/mL) and at 48 h (0.84 +/- 0.4 microg/mL) (P = 0.33). FIC block provided adequate analgesia in most cases. No severe adverse effects were noted. We conclude that the bupivacaine plasma concentrations during continuous FIC block in children are within the safety margins. FIC block is well tolerated, and provides satisfactory pain relief in most cases. IMPLICATIONS: In this study, we have shown that, in children, continuous fascia iliaca compartment block, a technique providing neural blockade of the thigh and the anterior part of the knee, was associated with safe plasma bupivacaine concentrations, was well tolerated, and provided satisfactory pain scores in most cases.

Absolute measurements and theoretical calculations of photoionization cross sections along the isonuclear sequence of multiply charged barium ions.

Photoionization of multiply charged ions of the Ba isonuclear sequence up to Ba6+ has been studied in a beam-beam experiment. A very strong increase in the resonance structures was observed when moving from Ba2+ to Ba6+. Absolute values of the photoionization cross sections were measured for Ba2+ and Ba3+ ions. The interpretation of the results is provided using theoretical multiconfiguration Dirac-Fock and relativistic random phase approximation calculations, showing that the collapse of the nf orbitals occurs for Ba4+.

Photoionization of highly charged ions using an ECR ion source and undulator radiation

Photoionization of Xe4+ to Xe7+ ions was studied by combining an electron cyclotron resonance ion source with synchrotron radiation. Multiconfiguration Dirac-Fock calculations were performed to interpret the data. Many autoionization lines were measured and identified, resulting from excitation of a 4d electron into nf and np orbitals followed by Auger decay of the excited states. Continuum photoionization is negligible for the higher members of the isonuclear series.

[Severe hyponatremic encephalopathy after pediatric surgery: report of seven cases and recommendations for management and prevention]. / Encéphalopathie hyponatrémique sévère après chirurgie pédiatrique: analyse de sept cas cliniques et recommandations pour un traitement et une prévention efficaces.

BACKGROUND: The infusion of hypotonic solutions in the perioperative period can lead to the development of hyponatraemic encephalopathy which is a severe, life threatening but preventable complication. CLINICAL PRESENTATION: Seven children aged 3-6 yr, ASA 1 or 2, operated on for a scheduled surgical procedure, presented at the 11th postoperative hour with seizures or status epilepticus, associated with vomiting (5/7), and a constant loss of consciousness (median Glasgow Coma Scale at 7), while one child presented with a respiratory arrest. At arrival in ICU, serum sodium was 120 mmol.L-1. All children had received in the perioperative period an hypotonic solution infusion (mainly dextrose 5%), at a high rate for most of them. Management included mechanical ventilation (3/7), antiepileptic drugs (7/7), fluid restriction (7/7), sodium chloride infusion (5/7), and diuretics (6/7). Serum sodium increased to a mean of 135 mmol.L-1 in 12 hours. Six children had a good neurologic outcome while one child died from brain death. CONCLUSION: The use of hypotonic solute in the perioperative period can lead to hyponatremic encephalopathy, a severe neurologic complication of acute hyponatremia. It must be prevented by the use of appropriate solutions i-e isotonic fluids in regards of the low free water elimination capacities of the surgical patient.

[Severe lactic acidosis and thiamine deficiency during parenteral nutrition in a child]. / Acidose lactique sévère et déficit en thiamine au cours d'une nutrition parentérale chez un enfant.

We report the case of a leukemic child treated with chemotherapy and parenteral nutrition for three weeks, who developed a severe lactic acidosis. Clinical features included both digestive and neurological disorders associated with a moderate cardiovascular collapse. After elimination of a toxic, a neoplastic or a septic cause, a thiamin (or vitamin B1) deficiency was suspected because of the lack of vitamin supply to parenteral nutrition. Intravenous administration of thiamin rapidly controlled lactic and clinical features. The diagnosis was confirmed by a low plasmatic concentration of thiamin. Thiamin deficiency must be suspected in case of severe lactic acidosis during parenteral nutrition and systematically prevented by supply of vitamins.