Anne Renault

Outcomes of Critically Ill Patients With Hematologic Malignancies: Prospective Multicenter Data From France and Belgium—A Groupe de Recherche Respiratoire en Réanimation Onco-Hématologique Study

PURPOSE Patients with hematologic malignancies are increasingly admitted to the intensive care unit (ICU) when life-threatening events occur. We sought to report outcomes and prognostic factors in these patients. PATIENTS AND METHODS Ours was a prospective, multicenter cohort study of critically ill patients with hematologic malignancies. Health-related quality of life (HRQOL) and disease status were collected after 3 to 6 months. Results Of the 1,011 patients, 38.2% had newly diagnosed malignancies, 23.1% were in remission, and 24.9% had received hematopoietic stem-cell transplantations (HSCT, including 145 allogeneic). ICU admission was mostly required for acute respiratory failure (62.5%) and/or shock (42.3%). On day1, 733 patients (72.5%) received life-supporting interventions. Hospital, day-90, and 1-year survival rates were 60.7%, 52.5%, and 43.3%, respectively. By multivariate analysis, cancer remission and time to ICU admission less than 24 hours were associated with better hospital survival. Poor performance status, Charlson comorbidity index, allogeneic HSCT, organ dysfunction score, cardiac arrest, acute respiratory failure, malignant organ infiltration, and invasive aspergillosis were associated with higher hospital mortality. Mechanical ventilation (47.9% of patients), vasoactive drugs (51.2%), and dialysis (25.9%) were associated with mortality rates of 60.5%, 57.5%, and 59.2%, respectively. On day 90, 80% of survivors had no HRQOL alterations (physical and mental health similar to that of the overall cancer population). After 6 months, 80% of survivors had no change in treatment intensity compared with similar patients not admitted to the ICU, and 80% were in remission. CONCLUSION Critically ill patients with hematologic malignancies have good survival, disease control, and post-ICU HRQOL. Earlier ICU admission is associated with better survival.

Interaction of the third helix of Antennapedia homeodomain and a phospholipid monolayer, studied by ellipsometry and PM-IRRAS at the air–water interface

The penetratin peptide, a 16 amino acid sequence extracted from Antennapedia homeodomain, is able to translocate across a neural cell membrane through an unknown mechanism, most likely a non-specific interaction with membrane lipids. Beyond its potential application as vector targeting small hydrophilic molecules and enabling them to reach a cell nucleus, this observation raises intriguing questions concerning the physico-chemistry of peptide-lipid interactions. Here we present a study of the role of lipid surface pressure and head charge on the mechanism of interaction. This was performed using optical techniques: surface infrared spectroscopy and ellipsometry, applied to a monolayer of phospholipids deposited at the air-water interface. Determination of the structure and orientation of peptides and lipids (separately or together) evidenced that electrostatic rather than amphiphilic interactions determine the peptide adsorption and its action on lipids.

The protein net electric charge determines the surface rheological properties of ovalbumin adsorbed at the air–water interface

Abstract Adsorption of purified diphosphorylated Al-ovalbumin at the air–water interface was studied by ellipsometry, surface tension, and shear elastic constant measurements. The value of pH did not significantly affect the final value of surface concentration. It affected slightly the kinetics of surface pressure increase and the final value of surface pressure. The interfacial rheology was affected strongly by pH. The interface exhibited a maximum of the shear elastic constant at a pH close to the isoelectric pH of ovalbumin. The bulk protein concentration also had a more pronounced effect on the surface rheology when the protein net charge was low. At a pH where the protein net charge is negative, an increase of the ionic strength increased the final value of the shear elastic constant. The results suggest that interactions between adsorbed ovalbumin molecules, which form slowly in the adsorbed layer upon conformational rearrangements, impart rigidity to the interface, and that these intermolecular associations are hindered at high protein net charge.

Characterization of the growth of 2D protein crystals on a lipid monolayer by ellipsometry and rigidity measurements coupled to electron microscopy.

We present here some sensitive optical and mechanical experiments for monitoring the process of formation and growth of two-dimensional (2D) crystals of proteins on a lipid monolayer at an air-water interface. The adsorption of proteins on the lipid monolayer was monitored by ellipsometry measurements. An instrument was developed to measure the shear elastic constant (in plane rigidity) of the monolayer. These experiments have been done using cholera toxin B subunit (CTB) and annexin V as model proteins interacting with a monosialoganglioside (GM1) and dioleoylphosphatidylserine (DOPS), respectively. Electron microscopy observations of the protein-lipid layer transferred to grids were systematically used as a control. We found a good correlation between the measured in-plane rigidity of the monolayer and the presence of large crystalline domains observed by electron microscopy grids. Our interpretation of these data is that the crystallization process of proteins on a lipid monolayer passes through at least three successive stages: 1) molecular recognition between protein and lipid-ligand, i.e., adsorption of the protein on the lipid layer; 2) nucleation and growth of crystalline patches whose percolation is detected by the appearance of a non-zero in-plane rigidity; and 3) annealing of the layer producing a slower increase of the lateral or in-plane rigidity.

Important questions asked by family members of intensive care unit patients.

Objectives: Relatives often lack important information about intensive care unit patients. High-quality information is crucial to help relatives overcome the often considerable situational stress and to acquire the ability to participate in the decision-making process, most notably regarding the appropriate level of care. We aimed to develop a list of questions important for relatives of patients in the intensive care unit. Design, Setting, and Participants: This was a multicenter study. Questions asked by relatives of intensive care unit patients were collected from five different sources (literature, panel of 28 intensive care unit nurses and physicians, 1-wk survey of nurses and 1-wk survey of physicians in 14 intensive care units, and in-depth interviews with 14 families). After a qualitative analysis (framework approach and thematic analysis), questions were rated by 22 relatives and 14 intensive care unit physicians, and the ratings were analyzed using principal component analysis and hierarchical clustering. Results: The five sources produced 2,135 questions. Removal of duplicates and redundancies left 443 questions, which were distributed among nine predefined domains using a framework approach (“diagnosis,” “treatment,” “prognosis,” “comfort,” “interaction,” “communication,” “family,” “end of life,” and “postintensive care unit management”). Thematic analysis in each domain led to the identification of 46 themes, which were reworded as 46 different questions. Ratings by relatives and physicians showed that 21 of these questions were particularly important for relatives of intensive care unit patients. Conclusion: This study increases knowledge about the informational needs of relatives of intensive care unit patients. This list of questions may prove valuable for both relatives and intensive care unit physicians as a tool for improving communication in the intensive care unit.

Aggregation of puroindoline in phospholipid monolayers spread at the air-liquid interface.

Puroindolines, cationic and cystine-rich low molecular weight lipid binding proteins from wheat seeds, display unique foaming properties and antimicrobial activity. To unravel the mechanism involved in these properties, the interaction of puroindoline-a (PIN-a) with dipalmitoylphosphatidylcholine (DPPC) and dipalmitoylphosphatidylglycerol (DPPG) monolayers was studied by coupling Langmuir-Blodgett and imaging techniques. Compression isotherms of PIN-a/phospholipid monolayers and adsorption of PIN-a to lipid monolayers showed that the protein interacted strongly with phospholipids, especially with the anionic DPPG. The electrostatic contribution led to the formation of a highly stable lipoprotein monolayer. Confocal laser scanning microscopy and atomic force microscopy showed that PIN-a was mainly inserted in the liquid-expanded phase of the DPPC, where it formed an aggregated protein network and induced the fusion of liquid-condensed domains. For DPPG, the protein partitioned in both the liquid-expanded and liquid-condensed phases, where it was aggregated. The extent of protein aggregation was related both to the physical state of phospholipids, i.e., condensed or expanded, and to the electrostatic interactions between lipids and PIN-a. Aggregation of PIN-a at air-liquid and lipid interfaces could account for the biological and technological properties of this wheat lipid binding protein.

Complicated grief after death of a relative in the intensive care unit

An increased proportion of deaths occur in the intensive care unit (ICU). We performed this prospective study in 41 ICUs to determine the prevalence and determinants of complicated grief after death of a loved one in the ICU. Relatives of 475 adult patients were followed up. Complicated grief was assessed at 6 and 12 months using the Inventory of Complicated Grief (cut-off score >25). Relatives also completed the Hospital Anxiety and Depression Scale at 3 months, and the Revised Impact of Event Scale for post-traumatic stress disorder symptoms at 3, 6 and 12 months. We used a mixed multivariate logistic regression model to identify determinants of complicated grief after 6 months. Among the 475 patients, 282 (59.4%) had a relative evaluated at 6 months. Complicated grief symptoms were identified in 147 (52%) relatives. Independent determinants of complicated grief symptoms were either not amenable to changes (relative of female sex, relative living alone and intensivist board certification before 2009) or potential targets for improvements (refusal of treatment by the patient, patient died while intubated, relatives present at the time of death, relatives did not say goodbye to the patient, and poor communication between physicians and relatives). End-of-life practices, communication and loneliness in bereaved relatives may be amenable to improvements. End-of-life care and communication in the ICU are associated with the prevalence of complicated grief http://ow.ly/DCqjB

Surface-Induced Polymerization of Actin

Living cells contain a very large amount of membrane surface area, which potentially influences the direction, the kinetics, and the localization of biochemical reactions. This paper quantitatively evaluates the possibility that a lipid monolayer can adsorb actin from a nonpolymerizing solution, induce its polymerization, and form a 2D network of individual actin filaments, in conditions that forbid bulk polymerization. G- and F-actin solutions were studied beneath saturated Langmuir monolayers containing phosphatidylcholine (PC, neutral) and stearylamine (SA, a positively charged surfactant) at PC:SA = 3:1 molar ratio. Ellipsometry, tensiometry, shear elastic measurements, electron microscopy, and dark-field light microscopy were used to characterize the adsorption kinetics and the interfacial polymerization of actin. In all cases studied, actin follows a monoexponential reaction-limited adsorption with similar time constants (approximately 10(3) s). At a longer time scale the shear elasticity of the monomeric actin adsorbate increases only in the presence of lipids, to a 2D shear elastic modulus of mu approximately 30 mN/m, indicating the formation of a structure coupled to the monolayer. Electron microscopy shows the formation of a 2D network of actin filaments at the PC:SA surface, and several arguments strongly suggest that this network is indeed causing the observed elasticity. Adsorption of F-actin to PC:SA leads more quickly to a slightly more rigid interface with a modulus of mu approximately 50 mN/m.

Native spider silk as a biological optical fiber

In this study, we demonstrate the use of eco-friendly native spider silk as an efficient optical fiber in air, highly bent fibers, and physiological liquid. We also integrated the silk filament in a photonic chip made of polymer microstructures fabricated by UV lithography. The molding process is non-destructive for silk and leads to an efficient micro-optical coupling between silk and synthetic optical structures. These optical performances combined with the unique biocompatibility, bioresorbability, flexibility, and tensile strength of silk filaments pave the way for new applications in biological media and for original biophotonic purposes.

Clinical Relevance of Classification According to Weaning Difficulty

OBJECTIVE: To evaluate the clinical relevance of the weaning from mechanical ventilation classification system derived from the 2005 international consensus conference, in patients who receive mechanical ventilation for more than 48 hours, and evaluate its correlation with prognosis. METHODS: We conducted a retrospective cohort study in a 12-bed intensive care unit (ICU) in a teaching hospital. We included patients who required > 48 hours of mechanical ventilation and who passed a spontaneous breathing trial (SBT). Weaning and sedation were monitored according to standardized protocol-directed procedures. We collected data on physiological characteristics, mechanical ventilation duration, ICU and hospital stay, and mortality from the medical records database. We assessed one-year mortality with a prospective, standardized method. Multivariate logistic regression was performed to evaluate the association between weaning categories and outcome. RESULTS: We included 329 ventilation episodes, in which 115 patients passed at least one SBT. Thirty-four patients (30%) succeeded in their first SBT (simple weaning group), 47 patients (40%) succeeded in their 2nd or 3rd SBT or in less than 7 days of weaning (the difficult weaning group), and 34 patients (30%) required more than 3 SBTs or more than 7 days of weaning (the prolonged weaning group). There were significant differences in ICU and hospital mortality between the simple, difficult, and prolonged-weaning groups. Prolonged weaning was an independent risk factor for longer ICU stay (odds ratio 15.11, 95% CI 1.61–141.91, P = .01) and hospital mortality (odds ratio 3.66, 95% CI 0.99–13.51). However, the weaning process did not impact one-year mortality (odds ratio 2.61, 95% CI 0.82–8.35). CONCLUSIONS: The new weaning classification system is clinically relevant and correlates to ICU and hospital mortality, but not to one-year mortality.