Clipping of MCA aneurysms: how I do it

Introduction: Aneurysms located at the middle cerebral artery bifurcation remain a clear neurosurgical indication. We detail here the steps necessary to enable safe surgery for Sylvian fissure aneurysms. Methods: An angiogram with 3D reconstruction is obtained and reviewed intraoperatively, just prior to the skin incision. During the exposure, the cistern is kept open by small cottonoids, thereby avoiding brain retraction. Continuous monitoring of MEPs along with ICG microscopic angio-fluorescence allows for detection of vascular compromise. Intraoperative angiography with 3D reconstruction allows for immediate correction of less than satisfactory surgical outcome. Conclusions: Careful planning of surgical strategy followed by a minimally invasive technique (with continuous neuro-monitoring) ensures safe surgery. The availability of intra-operative radiological guidance allows for optimal managemen

Are terminally ill patients dying in the ICU suitable for non-heart beating organ donation?

Objective: To evaluate the feasibility of implementing aprogram of controlled non-heart beating organ donation, in patients undergoing the withdrawal of intensive care treatment. Design and setting: Prospective observational study. Medical and Surgical ICUs in atertiary university hospital. Patients: Consecutive patients younger than 70 years dying in the ICU after treatment withdrawal for dire neurological prognosis. Measurements and results: We analyzed prospectively collected data from the ICU clinical information system. Seventy-three of 516 ICU deaths (13%) were identified, equally distributed among traumatic, stroke, and anoxic brain injury. The management and the course in these three diagnostic categories were similar. All patients underwent withdrawal of mechanical ventilation and half were extubated. Median time to death was of 4.8 h (IQR 1.4-11.5). In 70% of cases the patient received analgesia and 30% sedation. Such treatment was not related to earlier death. Hypotension was observed in 50% of patients during the 30 min preceding cardiac death. Conclusions: With our current management of terminal patients controlled non-heart beating organ procedure may be difficult due to the duration and variability of the dying process. This observation suggests that we can perform better by evaluating this process moreclosel

Augmented reality in the surgery of cerebral arteriovenous malformations: technique assessment and considerations

Background: Augmented reality technology has been used for intraoperative image guidance through the overlay of virtual images, from preoperative imaging studies, onto the real-world surgical field. Although setups based on augmented reality have been used for various neurosurgical pathologies, very few cases have been reported for the surgery of arteriovenous malformations (AVM). We present our experience with AVM surgery using a system designed for image injection of virtual images into the operating microscope's eyepiece, and discuss why augmented reality may be less appealing in this form of surgery. Methods: N = 5 patients underwent AVM resection assisted by augmented reality. Virtual three-dimensional models of patients' heads, skulls, AVM nidi, and feeder and drainage vessels were selectively segmented and injected into the microscope's eyepiece for intraoperative image guidance, and their usefulness was assessed in each case. Results: Although the setup helped in performing tailored craniotomies, in guiding dissection and in localizing drainage veins, it did not provide the surgeon with useful information concerning feeder arteries, due to the complexity of AVM angioarchitecture. Conclusion: The difficulty in intraoperatively conveying useful information on feeder vessels may make augmented reality a less engaging tool in this form of surgery, and might explain its underrepresentation in the literature. Integrating an AVM's hemodynamic characteristics into the augmented rendering could make it more suited to AVM surgery

RE-EDS Using GAFF Topologies: Application to Relative Hydration Free-Energy Calculations for Large Sets of Molecules

Free-energy differences between pairs of end-states can be estimated based on molecular dynamics (MD) simulations using standard pathway-dependent methods such as thermodynamic integration (TI), free-energy perturbation, or Bennett's acceptance ratio. Replica-exchange enveloping distribution sampling (RE-EDS), on the other hand, allows for the sampling of multiple end-states in a single simulation without the specification of any pathways. In this work, we use the RE-EDS method as implemented in GROMOS together with generalized AMBER force field (GAFF) topologies, converted to a GROMOS-compatible format with a newly developed GROMOS++ program amber2gromos, to compute relative hydration free energies for a series of benzene derivatives. The results obtained with RE-EDS are compared to the experimental data as well as calculated values from the literature. In addition, the estimated free-energy differences in water and in vacuum are compared to values from TI calculations carried out with GROMACS. The hydration free energies obtained using RE-EDS for multiple molecules are found to be in good agreement with both the experimental data and the results calculated using other free-energy methods. While all considered free-energy methods delivered accurate results, the RE-EDS calculations required the least amount of total simulation time. This work serves as a validation for the use of GAFF topologies with the GROMOS simulation package and the RE-EDS approach. Furthermore, the performance of RE-EDS for a large set of 28 end-states is assessed with promising results

L'élevage, un atout pour le développement durable des territoires dans les régions de polyculture-élevage

Comment l’élevage peut-il contribuer au développement durable des territoires en région de polyculture-élevage ? A l’inverse, les objectifs de développement rural peuvent-ils conforter la durabilité de l’élevage dans ces situations ? Notre réflexion est fondée sur des recherches interdisciplinaires sur l’agriculture et l’environnement dans différentes régions françaises (Coteaux de Gascogne, Plaine de Niort, Bretagne, Pays de Caux et Lorraine). Nos recherches appréhendent les relations entre transformations des activités agricoles et changements de l’utilisation des terres en lien avec les services écosystémiques. Ces questions exigent d’aborder de multiples dimensions de la gestion de l’espace et des ressources naturelles par l’élevage. Nos résultats illustrent la complexité et l’imbrication des questions de gestion de l’espace, de la parcelle au paysage, soulevées par le développement durable de l’élevage en milieu de polyculture-élevage. Au niveau de l’exploitation, ils éclairent les stratégies décisionnelles des agriculteurs. Au niveau du tissu d’exploitations, ils soulignent l’importance des relations et des échanges entre exploitations. L’expérimentation de systèmes innovants contribue à évaluer la compatibilité des enjeux territoriaux et de durabilité des exploitations. Enfin, nous proposons des pistes de recherche et d’actions pour conforter la contribution de l’élevage au développement durable des territoires ruraux

Vitamin D5 in Arabidopsis thaliana

Abstract Vitamin D3 is a secosterol hormone critical for bone growth and calcium homeostasis, produced in vertebrate skin by photolytic conversion of the cholesterol biosynthetic intermediate provitamin D3. Insufficient levels of vitamin D3 especially in the case of low solar UV-B irradiation is often compensated by an intake of a dietary source of vitamin D3 of animal origin. Small amounts of vitamin D3 were described in a few plant species and considered as a peculiar feature of their phytochemical diversity. In this report we show the presence of vitamin D5 in the model plant Arabidopsis thaliana. This plant secosterol is a UV-B mediated derivative of provitamin D5, the precursor of sitosterol. The present work will allow a further survey of vitamin D distribution in plant species

Impact of medical practice guidelines on the assessment of patients with acute coronary syndrome without persistent ST segment elevation

Objective. To assess the impact of introducing clinical practice guidelines on acute coronary syndrome without persistent ST segment elevation (ACS) on patient initial assessment. Design. Prospective before-after evaluation over a 3-month period. Setting. The emergency ward of a tertiary teaching hospital. Patients. All consecutive patients with ACS evaluated in the emergency ward over the two 3-month periods. Intervention. Implementation of the practice guidelines, and the addition of a cardiology consultant to the emergency team. Main outcome measures. Diagnosis, electrocardiogram interpretation, and risk stratification after the initial evaluation. Results. The clinical characteristics of the 328 and 364 patients evaluated in the emergency ward for suspicion of ACS before and after guideline implementation were similar. Significantly more patients were classified as suffering from atypical chest pain (39.6% versus 47.0%; P = 0.006) after guideline implementation. Guidelines availability was associated with significantly more formal diagnoses (79.9% versus 92.9%; P < 0.0001) and risk stratification (53.7% versus 65.4%, P < 0.0001) at the end of initial assessment. Conclusion. Guidelines implementation, along with availability of a cardiology consultant in the emergency room had a positive impact on initial assessment of patients evaluated for suspicion of ACS. It led to increased confidence in diagnosis and stratification by risk, which are the first steps in initiating effective treatment for this common conditio

Prospective monitoring of cefepime in intensive care unit adult patients

INTRODUCTION: Cefepime has been associated with a greater risk of mortality than other beta-lactams in patients treated for severe sepsis. Hypotheses for this failure include possible hidden side-effects (for example, neurological) or inappropriate pharmacokinetic/pharmacodynamic (PK/PD) parameters for bacteria with cefepime minimal inhibitory concentrations (MIC) at the highest limits of susceptibility (8 mg/l) or intermediate-resistance (16 mg/l) for pathogens such as Enterobacteriaceae, Pseudomonas aeruginosa and Staphylococcus aureus. We examined these issues in a prospective non-interventional study of 21 consecutive intensive care unit (ICU) adult patients treated with cefepime for nosocomial pneumonia. METHODS: Patients (median age 55.1 years, range 21.8 to 81.2) received intravenous cefepime at 2 g every 12 hours for creatinine clearance (CLCr) &gt;or= 50 ml/min, and 2 g every 24 hours or 36 hours for CLCr &lt; 50 ml/minute. Cefepime plasma concentrations were determined at several time-points before and after drug administration by high-pressure liquid chromatography. PK/PD parameters were computed by standard non-compartmental analysis. RESULTS: Seventeen first-doses and 11 steady states (that is, four to six days after the first dose) were measured. Plasma levels varied greatly between individuals, from two- to three-fold at peak-concentrations to up to 40-fold at trough-concentrations. Nineteen out of 21 (90%) patients had PK/PD parameters comparable to literature values. Twenty-one of 21 (100%) patients had appropriate duration of cefepime concentrations above the MIC (T&gt;MIC &gt;or= 50%) for the pathogens recovered in this study (MIC &lt;or= 4 mg/l), but only 45 to 65% of them had appropriate coverage for potential pathogens with cefepime MIC &gt;or= 8 mg/l. Moreover, 2/21 (10%) patients with renal impairment (CLCr &lt; 30 ml/minute) demonstrated accumulation of cefepime in the plasma (trough concentrations of 20 to 30 mg/l) in spite of dosage adjustment. Both had symptoms compatible with non-convulsive epilepsy (confusion and muscle jerks) that were not attributed to cefepime-toxicity until plasma levels were disclosed to the caretakers and symptoms resolved promptly after drug arrest. CONCLUSIONS: These empirical results confirm the suspected risks of hidden side-effects and inappropriate PK/PD parameters (for pathogens with upper-limit MICs) in a population of ICU adult patients. Moreover, it identifies a safety and efficacy window for cefepime doses of 2 g every 12 hours in patients with a CLCr &gt;or= 50 ml/minute infected by pathogens with cefepime MICs &lt;or= 4 mg/l. On the other hand, prompt monitoring of cefepime plasma levels should be considered in case of lower CLCr or greater MICs

Modelling regional land use: articulating the farm and the regional levels by combining farmers' decision rules and regional stochastic regularities

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Intraoperative angiography reloaded: a new hybrid operating theater for combined endovascular and surgical treatment of cerebral arteriovenous malformations: a pilot study on 25 patients

Background: Multimodality treatment suites for patients with cerebral arteriovenous malformations (AVM) have recently become available. This study was designed to evaluate feasibility, safety and impact on treatment of a new intraoperative flat-panel (FP) based integrated surgical and imaging suite for combined endovascular and surgical treatment of cerebral AVM. Methods: Twenty-five patients with AVMs to treat with combined endovascular and surgical interventions were prospectively enrolled in this consecutive case series. The hybrid suite allows combined endovascular and surgical approaches with intraoperative scanner-like imaging (XperCT®) and intraoperative 3D rotational angiography (3D-RA). The impact of intraoperative multimodal imaging on feasibility, workflow of combined interventions, surgery, and unexpected imaging findings were analyzed. Results: Twenty-five patients (mean age 38 ± 18.6year) with a median Spetzler-Martin grade 2 AVM (range 1-4) underwent combined endovascular and surgical procedures. Sixteen patients presented with a ruptured AVM and nine with an unruptured AVM. In 16% (n = 4) of cases, intraoperative imaging visualized AVM remnants ≤3mm and allowed for completion of the resections in the same sessions. Complete resection was confirmed in all n = 16 patients who had follow-up angiography oneyear after surgery so far. All diagnostic and therapeutical steps, including angiographic control, were performed without having to move the patients Conclusion: The hybrid neurointerventional suite was shown to be a safe and useful setup which allowed for unconstrained combined microsurgical and neuroradiological workflow. It reduces the need for extraoperative angiographic controls and subsequent potential surgical revisions a second time, as small AVM remnants can be detected with high securit