Robust Light Driven Enzymatic Oxyfunctionalization via Immobilization of Unspecific Peroxygenase.

Unspecific peroxygenases have attracted interest in synthetic chemistry, especially for the oxidative activation of C-H bonds, as they only require hydrogen peroxide (H2 O2 ) instead of a cofactor. Due to their instability in even small amounts of H2 O2 , different strategies like enzyme immobilization or in situ H2 O2 production have been developed to improve the stability of these enzymes. While most strategies have been studied separately, a combination of photocatalysis with immobilized enzymes was only recently reported. To show the advantages and limiting factors of immobilized enzyme in a photobiocatalytic reaction, a comparison is made between free and immobilized enzymes. Adjustment of critical parameters such as (i) enzyme and substrate concentration, (ii) illumination wavelength and (iii) light intensity results in significantly increased enzyme stabilities of the immobilized variant. Moreover, under optimized conditions a turnover number of 334,500 was reached.

Anatomical variations of the renal artery based on the surgeon's direct observation: A French perspective.

INTRODUCTION: Renal arterial vasculature presents a great anatomical variation. A good knowledge of this anatomy is essential in the field of kidney transplantation. The aim of this study is to describe the anatomical variations of the renal arterial vasculature based on the retrieved but not transplanted kidneys (RNTK) and their contralateral grafted kidneys (CGK), which anatomy is described by surgeons themselves after aortic dissection during multi-organ procurement (MOP). MATERIAL AND METHODS: Using the "Crystal" database of the French "Agence de la biomédecine" (ABM), all RNTK were retrospectively selected over one year. Then, the arterial anatomy of each RNTK and their CGK was studied using the surgical and the histopathological reports. The surgical report was completed by the surgeon at the end of the MOP from deceased donors. The qualitative variables were expressed in numbers (percentage of the population) and were compared by a Chi2 test or an exact Fisher test depending on the sample size. A P-value of less than 0.05 was considered statistically significant. RESULTS: In total, 356 kidneys were studied (241 RNTK - 115 CGK), 69% had a single artery and 31% had multiple arteries (26% with two arteries and 5% with three or more). The incidence of multiple arteries was similar between the right and left kidneys (32% vs. 30% respectively). A modal arrangement with 1 artery on each side was present in 51% of cases. Thus, 1 in 2 donors had at least 2 arteries on one side. Multiple arteries were bilateral in 12% of cases. The RNTK group presented more kidneys with multiple arteries than the CGK group (35% vs. 22%). CONCLUSION: Our study shows a higher incidence of multiple renal arteries than the literature (31% vs. 25%). Thus, MOP can be considered as an accurate and reliable method of describing renal arterial anatomy, especially that some small arteries may be missed when using radiological or cadaveric dissection techniques.

Intensification of Photobiocatalytic Decarboxylation of Fatty Acids for the Production of Biodiesel.

Light-driven biocatalytic processes are notoriously hampered by poor penetration of light into the turbid reaction media. In this study, wirelessly powered light-emitting diodes are found to represent an efficient and scalable approach for process intensification of the photobiosynthetic production of diesel alkanes from renewable fatty acids.

Artificial Light-Harvesting Complexes Enable Rieske Oxygenase Catalyzed Hydroxylations in Non-Photosynthetic cells.

In this study, we coupled a well-established whole-cell system based on E. coli via light-harvesting complexes to Rieske oxygenase (RO)-catalyzed hydroxylations in vivo. Although these enzymes represent very promising biocatalysts, their practical applicability is hampered by their dependency on NAD(P)H as well as their multicomponent nature and intrinsic instability in cell-free systems. In order to explore the boundaries of E. coli as chassis for artificial photosynthesis, and due to the reported instability of ROs, we used these challenging enzymes as a model system. The light-driven approach relies on light-harvesting complexes such as eosin Y, 5(6)-carboxyeosin, and rose bengal and sacrificial electron donors (EDTA, MOPS, and MES) that were easily taken up by the cells. The obtained product formations of up to 1.3 g L-1 and rates of up to 1.6 mm h-1 demonstrate that this is a comparable approach to typical whole-cell transformations in E. coli. The applicability of this photocatalytic synthesis has been demonstrated and represents the first example of a photoinduced RO system.

Evolution of folate biosynthesis and metabolism across algae and land plant lineages.

Tetrahydrofolate and its derivatives, commonly known as folates, are essential for almost all living organisms. Besides acting as one-carbon donors and acceptors in reactions producing various important biomolecules such as nucleic and amino acids, as well as pantothenate, they also supply one-carbon units for methylation reactions. Plants along with bacteria, yeast and fungi synthesize folates de novo and therefore constitute a very important dietary source of folates for animals. All the major steps of folate biosynthesis and metabolism have been identified but only few have been genetically characterized in a handful of model plant species. The possible differences in the folate pathway between various plant and algal species have never been explored. In this study we present a comprehensive comparative study of folate biosynthesis and metabolism of all major land plant lineages as well as green and red algae. The study identifies new features of plant folate metabolism that might open new directions to folate research in plants.

Hydrocarbon Synthesis via Photoenzymatic Decarboxylation of Carboxylic Acids.

A recently discovered photodecarboxylase from Chlorella variabilis NC64A ( CvFAP) bears the promise for the efficient and selective synthesis of hydrocarbons from carboxylic acids. CvFAP, however, exhibits a clear preference for long-chain fatty acids thereby limiting its broad applicability. In this contribution, we demonstrate that the decoy molecule approach enables conversion of a broad range of carboxylic acids by filling up the vacant substrate access channel of the photodecarboxylase. These results not only demonstrate a practical application of a unique, photoactivated enzyme but also pave the way to selective production of short-chain alkanes from waste carboxylic acids under mild reaction conditions.

Selective Activation of C-H Bonds in a Cascade Process Combining Photochemistry and Biocatalysis.

Selective oxyfunctionalizations of inert C-H bonds can be achieved under mild conditions by using peroxygenases. This approach, however, suffers from the poor robustness of these enzymes in the presence of hydrogen peroxide as the stoichiometric oxidant. Herein, we demonstrate that inorganic photocatalysts such as gold-titanium dioxide efficiently provide H2 O2 through the methanol-driven reductive activation of ambient oxygen in amounts that ensure that the enzyme remains highly active and stable. Using this approach, the stereoselective hydroxylation of ethylbenzene to (R)-1-phenylethanol was achieved with high enantioselectivity (>98 % ee) and excellent turnover numbers for the biocatalyst (>71 000).

An attempt to validate the modification of the American-European consensus definition of acute lung injury/acute respiratory distress syndrome by the Berlin definition in a university hospital.

PURPOSE: The Berlin definition for acute respiratory distress syndrome (ARDS) is a new proposal for changing the American-European consensus definition but has not been assessed prospectively as yet. In the present study, we aimed to determine (1) the prevalence and incidence of ARDS with both definitions, and (2) the initial characteristics of patients with ARDS and 28-day mortality with the Berlin definition. METHODS: We performed a 6-month prospective observational study in the ten adult ICUs affiliated to the Public University Hospital in Lyon, France, from March to September 2012. Patients under invasive or noninvasive mechanical ventilation, with PaO2/FiO2 <300 mmHg regardless of the positive end-expiratory pressure (PEEP) level, and acute onset of new or increased bilateral infiltrates or opacities on chest X-ray were screened from ICU admission up to discharge. Patients with cardiogenic pulmonary edema were excluded. Patients were further classified into specific categories by using the American-European Consensus Conference and the Berlin definition criteria. The complete data set was measured at the time of inclusion. Patient outcome was measured at day 28 after inclusion. RESULTS: During the study period 3,504 patients were admitted and 278 fulfilled the American-European Consensus Conference criteria. Among them, 18 (6.5 %) did not comply with the Berlin criterion PEEP ≥ 5 cmH2O and 20 (7.2 %) had PaO2/FiO2 ratio ≤200 while on noninvasive ventilation. By using the Berlin definition in the remaining 240 patients (n = 42 mild, n = 123 moderate, n = 75 severe), the overall prevalence was 6.85 % and it was 1.20, 3.51, and 2.14 % for mild, moderate, and severe ARDS, respectively (P > 0.05 between the three groups). The incidence of ARDS amounted to 32 per 100,000 population per year, with values for mild, moderate, and severe ARDS of 5.6, 16.3, and 10 per 100,000 population per year, respectively (P < 0.05 between the three groups). The 28-day mortality was 35.0 %. It amounted to 30.9 % in mild, 27.9 % in moderate, and 49.3 % in severe categories (P < 0.01 between mild or moderate and severe, P = 0.70 between mild and moderate). In the Cox proportional hazard regression analysis ARDS stage was not significantly associated with patient death at day 28. CONCLUSIONS: The present study did not validate the Berlin definition of ARDS. Neither the stratification by severity nor the PaO2/FiO2 at study entry was independently associated with mortality.

[Organization of mechanical ventilation in French Intensive care units]. / Organisation de la ventilation artificielle dans les unités de réanimation en France.

OBJECTIVES: To clarify the procedures related to mechanical ventilation in the intensive care unit setting: allocation of ventilators, team education, maintenance and reference documents. STUDY DESIGN: Declarative survey. METHODS: Between September and December 2010, we assessed the assignment and types of ventilators (ICU ventilators, temporary repair ventilators, non-invasive ventilators [NIV], and transportation ventilators), medical and nurse education, maintenance of the ventilators, presence of reference documents. Results are expressed in median/range and proportions. RESULTS: Among the 62 participating ICUs, a median of 15 ventilators/ICU (range 1-50) was reported with more than one trademark in 47 (76%) units. Specific ventilators were used for NIV in 22 (35%) units, temporary repair in 49 (79%) and transportation in all the units. Nurse education courses were given by ICU physicians in 54 (87%) units or by a company in 29 (47%) units. Medical education courses were made by ICU senior physicians in 55 (89%) units or by a company in 21 (34%) units. These courses were organized occasionally in 24 (39%) ICU and bi-annually in 16 (26%) units. Maintenance procedures were made by the ICU staff in 39 (63%) units, dedicated staff (17 [27%]) or bioengineering technicians (14 [23%] ICU). Reference documents were written for maintenance procedures in 48 (77%) units, ventilator setup in 22 (35%) units and ventilator dysfunction in 20 (32%) ICU. CONCLUSIONS: This first survey shows disparate distribution of ventilators and practices among French ICU. Education and understanding of the proper use of ventilators are key issues for security improvement.

[A French survey on the practice of analgesia for thoracic surgery]. / Enquête sur les pratiques françaises d'analgésie en chirurgie thoracique (réalisée avec le concours de l'ARCOTHOVA).

OBJECTIVE: To assess the current practice of analgesia after thoracotomy and thoracoscopy in France. STUDY DESIGN: Cross-sectional practice survey. MATERIAL: Anaesthetist physicians, each referent for one of the French centres practicing thoracic surgery, during year 2012. METHODS: Electronic questionnaire about the activity of the centre in thoracic surgery, and modalities and estimated frequencies of different analgesic techniques. Primary assessment was the estimated percentage of acts, after imputation from original data. RESULTS: Eighty-four centres out of 103 (82 %) answered the questionnaire. Coupling locoregional to general anaesthesia involved 74 % of thoracotomies and 35 % of thoracoscopies. A practice (i.e. for more than 5 % of patients) of epidural analgesia was declared by 68 centres (81 %), and by 27 centres (32 %) for paravertebral block. The most current practices for epidural analgesia were: thoracic puncture, intraoperative initiation, ropivacaïne 0.2 % plus sufentanil, patient-controlled administration with infusion plus bolus, application more than 48hrs post surgery. The practice rates for technique of paravertebral block were: Eason & Wyatt 34 %, ultrasound-guided 24 %, internal 42 %. The most frequent systemic analgesia was patient-controlled intravenous morphine. Ketamine was used in 60 % of the cases. CONCLUSIONS: French practice of analgesia after thoracic surgery improved quality during the last decade, but more than one patient on four (compared to 8 % in UK) may have neither epidural nor paravertebral block, while such techniques are nowadays considered as standard.

[Interhospital transport with extracorporeal life support: results and perspectives after 5 years experience]. / Transport interhospitalier sous extracorporeal life support : résultats et perspectives après cinq ans d'expérience.

OBJECTIVE: Describing the experience of a referral center for interhospital patients transport treated with extracorporeal circulatory or respiratory support (ECLS), the difficulties encountered and the results obtained. STUDY DESIGN: Retrospective and observational study. PATIENTS AND METHODS: All patients with respiratory or circulatory failure accepted for extracorporeal assistance for which routine medical transport was life threatening. STATISTICAL ANALYSIS: A descriptive analysis was performed (median and interquartile deviation). Comparison of biological data was performed using a non-parametric Wilcoxon test and 5 years overall survival was determined by a Kaplan-Meier analysis. RESULTS: Over a 55-month period, 29 patients were selected for transportation under ECMO or ECLS. Indication was respiratory failure in 38 % of cases, hemodynamic instability in 52 % of cases and combined symptoms in 10 % of cases. Average duration of transportation was 40 km (9-64 km). No complication related to transport was observed. Incidence of intrahospital death was 57 %. There was no correlation between death and indication of ECLS. Five-year survival was 55 % and 39 % for venovenous and arteriovenous ECLS, respectively. CONCLUSION: In our experience, interhospital transport of patients under ECMO is feasible in satisfactory conditions of safety with trained team and standard procedures.

[Anaesthetic approach of paediatric pulmonary hypertension]. / Anesthésie et hypertension artérielle pulmonaire chez l'enfant en chirurgie non cardiaque.

Paediatric pulmonary arterial hypertension (PAH) is a challenge for the paediatric anaesthetist. Due to its high morbidity and mortality, support should be provided by a dedicated team. Understanding the pathophysiology of PAH allows performing an appropriate therapeutic approach. In case of high vascular pulmonary resistance, the main objectives of anaesthetic management are to maintain an optimal pulmonary flow and to avoid the decrease in systemic arterial pressure. Haemodynamic monitoring is essential to detect the onset of an acute PAH crisis but also to give direct information on the efficacy of treatment.

Influence of the site of measurement on the ability of plethysmographic variability index to predict fluid responsiveness.

BACKGROUND: Plethysmographic variability index (PVI) is an accurate predictor of fluid responsiveness in mechanically ventilated patients. However, the site of measurement of the plethysmographic waveform impacts its morphology and its respiratory variation. The goal of this study was to investigate the ability of PVI to predict fluid responsiveness at three sites of measurement (the forehead, ear, and finger) in mechanically ventilated patients under general anaesthesia. METHODS: We studied 28 subjects after induction of general anaesthesia. Subjects were monitored with a pulmonary artery catheter and three pulse oximeter sensors (the finger, ear, and forehead). Pulse pressure variation, central venous pressure, cardiac index (CI), and PVI measured at the forehead, ear, and finger (PVI(forehead), PVI(ear), and PVI(finger)) were recorded before and after fluid loading (FL). Subjects were responders to volume expansion if CI increased >15% after FL. RESULTS: Areas under the receiver-operating curves to predict fluid responsiveness were 0.906, 0.880, and 0.836 for PVI(forehead), PVI(ear), and PVI(finger), respectively (P<0.05). PVI(forehead), PVI(ear), and PVI(finger) had a threshold value to predict fluid responsiveness of 15%, 16%, and 12% with sensitivities of 89%, 74%, and 74% and specificities of 78%, 74%, and 67%, respectively. CONCLUSIONS: PVI can predict fluid responsiveness in anaesthetized and ventilated subjects at all three sites of measurement. However, the threshold values for predicting fluid responsiveness differ with the site of measurement. These results support the use of this plethysmographic dynamic index in the cephalic region when the finger is inaccessible or during states of low peripheral perfusion.

[Use of ECMO as a salvage therapy for refractory hypoxia secondary to a Lemierre's syndrome]. / Utilisation de l'ECMO comme technique de sauvetage d'une hypoxémie réfractaire compliquant un syndrome de Lemierre.

We reported the case of a young adult with a Lemierre syndrome, which was complicated by septic shock and ARDS. Because of rapid onset of a life-threatening hypoxemia (PaO(2)/FiO(2)=60) in the course of the ARDS despite mechanical ventilation, ECMO was started with jugular and femoral cannulas, as rescue therapy. Good control of hypoxemia was obtained and ECMO was set up for six days. No significant complication was observed. The course was nevertheless complicated by acute renal failure and a pleural fistula that necessitated separate-lung ventilation during 24 hours. After 48 days left in the ICU, the patient was sent to a rehabilitation unit.

[Massive recurrent haemoptysis in a pregnant woman with preeclampsia]. / Hémoptysies massives récidivantes chez une femme enceinte avec prééclampsie.

Massive haemoptysis are rare in pregnant woman. Besides usual causes of haemoptysis, cases of idiopathic haemoptysis have been described during pregnancy, probably with a hormonal role. A pregnant woman at 22 weeks amenorrhoea was admitted in intensive care unit for massive and recurrent haemoptysis, enhanced by bouts of hypertension in a context of preeclampsia. Arteriography showed bronchial hypervascularisation, with abnormally dilated bronchial arteries, and a lot of collateral arteries. Three sessions of bronchial artery embolization have been performed with success. The management of idiopathic haemoptysis in pregnant woman seems to be based on the usual algorithm of management, emphasizing on the control of blood pressure, and the key role of interventional radiology.

[How can we optimize medical orderings in intensive care unit (ICU)?]. / Optimisation des prescriptions en réanimation.

OBJECTIVES: To evaluate whether intensivists would accept to optimize their orderings of biological samplings, x-rays and target drugs and to assess the consequence on patient's outcome. STUDY DESIGN: Monocentric evaluation of medical economic procedure. METHODS: Meetings of consultants, registrars and residents started on Dec 21, 2006 with two to three sessions a year in order to evaluate the process of medical ordering. The physicians and pharmacists gave the results of orderings at each meeting. Orderings of systematic samplings, bedside x-rays and unjustified expansive drugs were discouraged, but target samplings and lung ultrasonography were encouraged. New residents were systematically taught about this programme. Meanwhile, monthly morbidity-mortality meetings were pursued in order to assess the consequences of this politics. RESULTS: While ICU total production increased by 3.4% and potentially evitable deaths decreased by 34%, annual expenses decreased by approximatively € 777,000 from 2006 to 2008. This was due to decreased orderings in biology by 30%, bedside x-rays by 10%, computed tomographic scans by 16% and target drugs by 35%. However, an increased ordering in four target drugs was observed in 2008 as compared with 2007. CONCLUSION: Multidisciplinary optimization of medical ordering can be efficient in ICU. However, a profit-sharing with ordering physicians would be necessary to prolong these effects.

[Comparison of ICG thoracic bioimpedance cardiac output monitoring system in patients undergoing cardiac surgery with pulmonary artery cardiac output measurements]. / Comparaison des valeurs de débit cardiaque obtenues à l'aide d'un nouveau système d'impédancemétrie thoracique avec les données du cathéter artériel pulmonaire en postopératoire de chirurgie cardiaque.

OBJECTIVE: Thoracic bioimpedance has been proposed for cardiac output (CO) determination and monitoring without calibration or thermodilution (ICG Monitor 862146, Philips Medical System, Philips, Suresnes, France). The accuracy and clinical applicability of this technology has not been fully evaluated in the cardiac surgery setting. We designed this prospective study to compare the accuracy of the ICG Monitor (CO(ICG)) versus pulmonary artery catheter standard bolus thermodilution (CO(PAC)) in patients after cardiac surgery or having benefited from cardiac surgery. STUDY DESIGN: Prospective, monocentric. MATERIAL AND METHODS: We studied 13 patients in the postoperative period. CO(ICG) and CO(PAC) were determined at the arrival in the intensive care unit and every four hours. Bland-Altman and Critchley and Critchley's analysis were used to assess the agreement between CO(ICG) and CO(PAC). RESULTS: CO(PAC) ranged from 2.6 to 11.0 l/min and CO(ICG) ranged from 1.8 to 11.7 l/min. There was a significant relationship between CO(PAC) and CO(ICG) (r=0.61 ; p<0.001). Agreement between CO(PAC) and CO(ICG) was -0.5+/-1.3 l/min (Bland-Altman analysis). Percentage error between the two methods was 49% (Critchley and Critchley's analysis). CONCLUSION: We found clinically unacceptable agreement between CO(ICG) and CO(PAC) in this setting. Despite its non invasiveness, this device cannot be recommended for CO monitoring in the postoperative period following cardiac surgery.

[Anaesthetic management of patients with Steinert myotonia: two case reports]. / Prise en charge anesthésique des patients porteurs de myotonie de Steinert: à propos de deux cas cliniques.

Steinert disease, the most common myopathy in adults, is a challenge for anaesthesiologists and critical care physicians during the perioperative time. The risk of myotonic crisis, malign hyperthermia and the increased sensitivity to anaesthetic drugs shouldn't be forgotten. On contrary, Steinert disease is rarely revealed in the postoperative period. It should be evoked in case of postoperative pulmonary complications such as difficult weaning with neurological symptoms like hypotonia or muscular weakness.