[The role of HFNC oxygen in pre-oxygenation prior to intubation and the practice of invasive procedures]

Over recent years, High Flow Nasal Cannula (HFNC) oxygen therapy has been more and more extensively applied in numerous medical settings, and it is now carried out in invasive procedures such as pre-oxygenation before orotracheal intubation, often leading to complications. More generally, pre-oxygenation is aimed at maintaining the highest possible oxygen saturation for extended periods of time. With this in mind, HFNC seems as effective as standard oxygen delivery with regard to hematosis in patients with mild or moderate hypoxemia, and it presents the advantage of reducing the adverse events associated with intubation. That said, during pre-oxygenation of patients with severe hypoxemia, non-invasive ventilation (NIV) is probably more effective than HFNC, especially in the prevention of respiratory events. However, in patients with little or no hypoxemia undergoing risky procedures such as bronchial endoscopy, HFNC allows better oxygen saturation than standard methods. To summarize, even though NIV remains useful in unstable patients, especially in decreasing desaturation episodes, HFNC could represent a reasonable alternative in case of poor tolerance, allowing continuous oxygenation of patients requiring digestive endoscopy or trans-esophageal ultrasound.

POS1412 FIRSTS RESULTS OF THE PRAISE STUDY (PATIENT-REPORTED AUTOIMMUNITY SECONDARY TO CANCER IMMUNOTHERAPY): MULTICENTRIC PROSPECTIVE COHORT STUDY ON AUTOIMMUNE DISEASES SECONDARY TO CANCER IMMUNOTHÉRAPY

Background

In cancer immunotherapy, T-lymphocyte activation can lead to secondary autoimmune diseases named OASI for Opportunistic Autoimmunity Secondary to cancer Immunotherapy [1]. The epidemiology of OASI deserves to be further studied due to the unadapted reporting of clinical trials and the lack of prospective studies. Moreover, literature focuses on the most severe OASI and/or on specific OASI (myocarditis, colitis, arthritis).

Objectives

Our goal was to determine incidence, severity of all grade OASI using a multicentric prospective patient cohort starting treatment with cancer immunotherapy.

Methods

We present a multicentric, prospective, observational, longitudinal, real life, French e-cohort. 900 patients treated with ipilimumumab and/or nivolumab will be included. Data is collected from the patient and the oncologist at inclusion, then patients report directly any symptom that could be suggestive of OASI with the help of monthly digital questionaries. In case an OASI is suspected, further confirmation is made with the practician in charge and by a paired analysis with the Système National De Santé (SNDS), the French health insurance registry.

Results

On the 19/01/2022, 439 patients were included, 310 males (70.6%) and 129 females (29.4%). Mean age is 66 years old with a median follow up of 192 days. 354 patients (80.6%) are treated with Nivolumab alone, 7 (1.6%) with Ipilimumab alone and 76 (17.8 %) with combined Nivolumab + Ipilimumab. 136 patients (31.6%) are treated for a non-small cell lung carcinoma, 107 patients (24.9%) for a clear cell renal carcinoma, 91 patients (21.2%) for a skin melanoma, 49 patients (11.4%) for a head or neck epidermoid carcinoma, 24 patients (5.6%) for another lung cancer sub-type, and 32 patients (5.3%) for another histological cancer type. The mean follow-up is 294 days (+/- 192). 83 patients (18.9%) died since the beginning of the follow up.

47 patients (10.7%) developed 63 OASI. The mean delay between the beginning of cancer immunotherapy and the OASI is 134.7 days (+/- 103.4).

Approximately, one third of the OASI were musculoskeletal diseases. The OASI included polymyalgia rheumatica (3 patients), psoriatic arthritis (1 patient), polyarthritis (1 patient) systemic lupus (1 patient), arthralgias and myalgias (8 patients), colitis (11 patients), dysthyroïditis (6 patients), hepatitis (4 patients), nephritis (3 patients), pneumonitis (2 patients), hypophysitis (2 patients), adrenal insufficiency (4 patients), myocarditis (1 patient), hemophagocytic lympho-histiocytosis (1 patient), and other types of OASI (15 patients).

26 patients (55% of patients with OASI, 5,9% of all patients) had to stop cancer immunotherapy due to an OASI, one because of a rheumatic disease (systemic lupus). 52 patients were treated with corticosteroids, 1 patient with methotrexate (psoriatic arthritis), 3 patients with infliximab (colitis) and 1 patient with abatacept (myocarditis). 1 patient died after an OASI (colitis).

Conclusion

The first results of this prospective study, using an original patient-centered methodology, confirm the expected incidence of autoimmune events secondary to cancer immunotherapy and the role of rheumatologists in their therapeutic management.

References

[1]Kostine M, Chiche L, Lazaro E, et al. Opportunistic autoimmunity secondary to cancer immunotherapy (OASI): An emerging challenge. Rev Med Interne. 2017;38(8):513-525. doi:10.1016/j.revmed.2017.01.004

Acknowledgements

BMS funded the study (unrestricted grant) but had no role in study design, data collection, analysis or decision to publish.

Disclosure of Interests

Eden Sebbag: None declared, Nicolas Cloarec: None declared, Philippe Barthelemy: None declared, Nathanaël Sedmak: None declared, Naima Hamamouche Consultant of: Work for Sanoia Digital CRO, Hervé Servy Consultant of: Work for Sanoia Digital CRO, Guillaume Desjeux Consultant of: Work for Sanoia Digital CRO, Isabelle Monnet: None declared, Abeer Najem: None declared, Marc Porneuf: None declared, Laetitia-Shanna Rajpar: None declared, Jérôme Meunier: None declared, Tévy San: None declared, Laure Chauvenet: None declared, Ariane DARUT JOUVE: None declared, Sabrina FALKOWSKI: None declared, Claudia Rizzo: None declared, Noémie Litrowski: None declared, Anthony Canellas: None declared, Jean-François Paitel: None declared, Marc Pracht: None declared, Jacques Cadranel: None declared, Laurence Weiss: None declared, Christos Chouaid: None declared, Thomas Aparicio: None declared, Stephane Nancey: None declared, Cécile Arnold: None declared, Erik Sauleau: None declared, Jaqcues-Eric Gottenberg: None declared

Re-evaluating pattern and process to understand resilience in transitional mixed conifer forests

A key challenge to maintaining resilient landscapes is adapting to and maintaining dynamic ecological processes. In fire-dependent ecosystems, this includes identifying and defining mechanisms through which fire influences forest structure and functionality. Interpretations of tree patterns via land survey records in the Lake States have often highlighted the importance of infrequent moderate to extreme disturbance events. However, historical survey methods are limited to observing higher severity disturbances and over large landscapes, thus it is not clear if the origin, structure, and forcing factors for either patterns or processes are adequately quantified by these methods. We used dendrochronological methods to determine how fire history and stand structure, including cohort structure, tree density, and spatial patterning, are linked within Lake States mixed conifer forests in Wisconsin. We found relatively short mean fire return intervals (MFRIs) ranging from 6 to 13 yr with little variation in fire frequency among sites. Current densities of red-pine-dominated forests are 4-37 times historical (ca. 1860) densities (mean 12×) and almost entirely spatially random, whereas historically forests were spatially aggregated at stand scales. Stands also contained multiple and/or loosely defined cohort structures suggesting very different controls operating historically than currently. Heterogeneity that helped maintain ecosystem resilience in these ecosystems historically came from frequent fire disturbance processes that affected stand-scale forest resistance. This was likely the historical dynamic across fire-adapted transitional pine forests of the Lake States.

Are There Categories of Corneal Shapes?

This study investigates the possible existence of different natural corneal shape categories. This is important to better describe cornea for both diagnostic and therapeutic assessments. We started by describing corneal shape of different populations as a function of influencing clinical data i.e. age, ametropia and gender. This was done by averaging Zernike polynomial (ZP) decomposition of the anterior surfaces in each subgroup. The results showed small but significant differences of shape that are supported by the literature. This motivated us to examine the feasibility of characterizing the normal corneal shape with an automatic method of clustering independent of any clinical a priori knowledge. Since we did not know beforehand the number of corneal categories, agglomerative hierarchical clustering was applied on ZP coefficients for a large database. The dendrogram based on the Ward's distance was evaluated with two different clustering validity indexes (coefficient of determination R² and semi partial R² (SPR²). The optimal number of categories was around four showing corneal shapes ranging from flatter to steeper.

Survival after pathogen exposure in group-living insects: don't forget the stress of social isolation!

A major cost of group-living is its inherent risk of pathogen infection. To limit this risk, many group-living animals have developed the capability to prophylactically boost their immune system in the presence of group members and/or to mount collective defences against pathogens. These two phenomena, called density-dependent prophylaxis and social immunity, respectively, are often used to explain why, in group-living species, individuals survive better in groups than in isolation. However, this survival difference may also reflect an alternative and often overlooked process: a cost of social isolation on individuals' capability to fight against infections. Here, we disentangled the effects of density-dependent prophylaxis, social immunity and stress of social isolation on the survival after pathogen exposure in group-living adults of the European earwig Forficula auricularia. By manipulating the presence of group members both before and after pathogen exposure, we demonstrated that the cost of being isolated after infection, but not the benefits of social immunity or density-dependent prophylaxis, explained the survival of females. Specifically, females kept constantly in groups or constantly isolated had higher survival rates than females that were first in groups and then isolated after infection. Our results also showed that this cost of social isolation was absent in males and that social isolation did not reduce the survival of noninfected individuals. Overall, this study gives a new perspective on the role of pathogens in social evolution, as it suggests that an apparently nonadaptive, personal immune process may promote the maintenance of group-living under pathogenic environments.

Work-related discussions between French rheumatologists and their rheumatoid arthritis patients

BACKGROUND

Rheumatoid arthritis (RA) causes significant impairment of physical function, and thus adversely affects patients' ability to work.

AIMS

To document how often work limitations are discussed by rheumatologists and RA patients during consultations.

METHODS

We conducted an observational study in a sample of French rheumatologists and in a parallel sample of patients recruited by pharmacists. We asked all rheumatologists in France practising in private practice or mixed practice (private practice and hospital) to participate in a telephone survey about their most recent consultation with an RA patient. Randomly selected pharmacists recruited RA patients to complete a questionnaire about their most recent consultation with their rheumatologist. We included patients aged 20-59, with a paid job or unemployed. We calculated the proportion of consultations including work-related discussions in both samples.

RESULTS

Of the 1737 rheumatologists contacted, 153 (9%) described consultations with eligible patients. Of the 1200 pharmacists contacted, 39 (3%) recruited 81 RA patients. The proportion of consultations including work-related discussions was 50% [95% confidence interval (CI) 42-58%] in the rheumatologist sample and 52% (95% CI 41-63%) in the patient sample. The most frequent subject of discussion (88%) was physical problems related to work in both samples.

CONCLUSIONS

This is the first study to document the proportion of consultations where rheumatologists and their RA patients discuss work. Both specialists and patients reported that work was discussed in one in every two consultations.

Automatic 3D reconstruction of quasi-planar stereo Scanning Electron Microscopy (SEM) images

Scanning Electron Microscopy (SEM) is widely used in science to characterize the surface roughness of materials. Three-dimensional information can be obtained with SEM based on stereovision techniques. A stereo pair is typically obtained by tilting the sample by a few degrees. In this paper we present a fully automated method for 3D reconstruction from a SEM stereo pair without any particular constraint. Results are presented for corneal stromal surfaces.

Analysis of fluoride in toothpastes on the Belgian market

We developed a method for the quantitative determination of sodium fluoride (NaF), sodium monofluorophosphate (SMFP) and amine fluoride (AmF) in toothpastes on the Belgian market. Samples were suspended in water and the determination was made using anion chromatography with conductivity detection after chemical suppression. The described ion chromatographic method is an easy and reliable isocratic high-performance liquid chromatography method for the determination of total soluble fluoride content in toothpastes. The analytical repeatability and reproducibility, the matrix effects and the method's decision limit of three different toothpastes containing NaF, SMFP and AmF at a concentration close to the permitted one of 0.15 g % total F are determined. All the samples analysed are in conformity with the Cosmetics Directive 76/768/EC; none exceeds the limit of 0.15 g %.

Optical reflectivity of thin rough films: application to ellipsometric measurements on liquid films

Equations to calculate the optical properties of a flat but rough interface are given. This interface is supposed to be much thinner than the wavelength of the light, and made of N-1 layers of refractive indices n{m} (for layer m ) between two media of refractive indices n{0} and n{N}. The interfaces separating two layers are rough. The roughness is supposed to have weak slopes (mid R:nablaZmid R:(z)1). These equations can be solved very simply for any N values. The explicit solution for N=2 (one rough layer) is given for the incidence angle equal to the Brewster angle in order to apply the result to ellipsometric measurements, specially on liquid interfaces whose roughness originates from thermal fluctuations and is depending on a small number of parameters.

3D average human corneal models

In this paper we propose a method of building an average model or atlas of the cornea based on topographic data. Specific models can be constructed for the left or right eye, gender, age, or ametropia, to assess differences and similarities. An application of this atlas construction methodology to the study of corneal shape evolution with age is presented. Results show significant differences between age groups. This numerical atlas could also be helpful in the design of algorithms targeting the detection of corneal shape abnormalities, such as keratoconus or previous laser surgery.

The anti-amnesic and neuroprotective effects of donepezil against amyloid beta25-35 peptide-induced toxicity in mice involve an interaction with the sigma1 receptor

BACKGROUND AND PURPOSE

The acetylcholinesterase inhibitor, donepezil, is also a high affinity sigma(1) receptor agonist. We examined the involvement of sigma(1) receptors in its anti-amnesic and neuroprotective properties against amyloid beta(25-35) peptide-induced toxicity in mice.

EXPERIMENTAL APPROACH

Mice were given an intracerebroventricular (i.c.v.) injection of Abeta(25-35) peptide (9 nmol) 7-9 days before being tested for spontaneous alternation and passive avoidance. Hippocampal lipid peroxidation was measured 7 days after Abeta(25-35) injection to evaluate oxidative stress. Donepezil, the sigma(1) agonist PRE-084 or the cholinesterase (ChE) inhibitors tacrine, rivastigmine and galantamine were administered either 20 min before behavioural sessions to check their anti-amnesic effects, or 20 min before Abeta(25-35) injection, or 24 h after Abeta(25-35) injection and then once daily before behavioural sessions, to check their pre- and post-i.c.v. neuroprotective activity, respectively.

KEY RESULTS

All the drugs tested were anti-amnesic, but only the effects of PRE-084 and donepezil were prevented by the sigma(1) antagonist BD1047. Only PRE-084 and donepezil showed neuroprotection when administered pre i.c.v.; they blocked lipid peroxidation and learning deficits, effects inhibited by BD1047. Post i.c.v., PRE-084 and donepezil showed complete neuroprotection whereas the other ChE inhibitors showed partial effects. BD1047 blocked these effects of PRE-084, attenuated those of donepezil, but did not affect the partial effects of the other ChE inhibitors.

CONCLUSIONS AND IMPLICATIONS

The potent anti-amnesic and neuroprotective effects of donepezil against Abeta(25-35)-induced toxicity involve both its cholinergic and sigma(1) agonistic properties. This dual action may explain its sustained activity compared to other ChE inhibitors.

Phase separation in molecular layers of macromolecules at the champagne-air interface

Bubble and foam stability, which are essential for the hallmark of champagne, rely on the concentration of amphiphilic macromolecules originating from the grape, which form molecular layers at the interface between champagne and gas. Ellipsometry and Brewster angle microscopy experiments were conducted at the air-champagne interface to analyse the lateral organization of the layers of macromolecules. Several kinds of phase separations - leading in some cases to two-dimensional foams - were identified. At the beginning of layer formation, condensed domains develop at the expense of dilute domains. Thereafter, phase separations occur within the condensed domains. These findings may allow advances in the implementation of methods predicting bubble and foam stability of champagnes.

Adsorption of oppositely charged polyelectrolyte/surfactant complexes at the air/water interface: formation of interfacial gels

The adsorption and complexation of polystyrene sulfonate (a highly charged anionic polyelectrolyte) and dodecyltrimethylammonium bromide (a cationic surfactant) at the air-water interface can lead to interfacial gels that strongly influence foam-film drainage and stability. The formation and characteristics of these gels have been studied by combining surface tension, ellipsometry, and foam-film drainage experiments. Simultaneously, the solution electromotive force is measured and used to track the polymer-surfactant interactions in the bulk solution. We find that surface gelation occurs above the critical aggregation concentration in solution but before bulk precipitation of the polymer-surfactant complexes. Furthermore, we reveal that strong readsorption of polymer-surfactant complexes occurs during the resolubilization of the precipitated complexes at high surfactant concentrations (i.e., >>critical micelle concentration). Seemingly overlooked in the past, this readsorption significantly influences the surface rheological properties and foam-film drainage of these systems.

Crossover from first-order to critical wetting: short-range tricritical wetting

We study wetting in liquid mixtures of methanol and the n-alkanes. Mixing alkanes of different chain lengths, we can examine the crossover between critical (continuous) and first-order (discontinuous) wetting transitions. Measurements of the film thickness and surface specific heat exponent indicate that for carbon number n between 11 (undecane) and 9 (nonane), there is a crossover from first-order to critical wetting with a tricritical wetting point between an effective alkane carbon number of 9.6 and 10. The observed variation of the specific heat exponent in the tricritical region agrees fairly well with the predictions of a simple mean-field model with only short-range interactions.

Wetting of biological lipids on aqueous substrates

We study the dynamics and final wetting state of skin lipids on water and brine by fluorescence microscopy and ellipsometry. When a lipid droplet is brought into contact with the water surface, a lipid wetting film spreads out rapidly by a Marangoni effect. Subsequently, this film undergoes a dewetting instability. However, the final equilibrium is not partial wetting. The film breaks up into droplets with a mesoscopic (approximately 50 A) film in between. These observations result from a subtle interplay between short- and long-range forces: surfactants naturally present in the lipids favor wetting, while the van der Waals forces oppose it. In addition, this reveals the likely organization of the hydrolipid film that covers and protects the skin.

Aging dynamics in a colloidal glass

The aging dynamics of colloidal suspensions of Laponite, a synthetic clay, is investigated using dynamic light scattering (DLS) and viscometry after a quench into the glassy phase. DLS allows to follow the diffusion of Laponite particles and reveals that there are two modes of relaxation. The fast mode corresponds to a rapid diffusion of particles within "cages" formed by the neighboring particles. The slow mode corresponds to escape from the cages: its average relaxation time increases exponentially fast with the age of the glass. In addition, the slow mode has a broad distribution of relaxation times, its distribution becoming larger as the system ages. Measuring the concomitant increase of viscosity as the system ages, we can relate the slowing down of the particle dynamics to the viscosity.

A multiscale optimization approach for the dynamic contour-based boundary detection issue

We present a new multiscale approach for deformable contour optimization. The method relies on a multigrid minimization method and a coarse-to-fine relaxation algorithm. This approach consists in minimizing a cascade of optimization problems of reduced and increasing complexity instead of considering the minimization problem on the full and original configuration space. Contrary to classical multiresolution algorithms, no reduction of image is applied. The family of defined energy functions are derived from the original (full resolution) objective function, ensuring that the same function is handled at each scale and that the energy decreases at each step of the deformable contour minimization process. The efficiency and the speed of this multiscale optimization strategy is demonstrated in the difficult context of the minimization of a region-based contour energy function ensuring the boundary detection of anatomical structures in ultrasound medical imagery. In this context, the proposed multiscale segmentation method is compared to other classical region-based segmentation approaches such as Maximum Likelihood or Markov Random Field-based segmentation techniques. We also extend this multiscale segmentation strategy to active contour models using a classical edge-based likelihood approach. Finally, time and performance analysis of this approach, compared to the (commonly used) dynamic programming-based optimization procedure, is given and allows to attest the accuracy and the speed of the proposed method.

Inhibition of the finite-time singularity during droplet fission of a polymeric fluid

When a drop of fluid detaches from a capillary, singular behavior ensues. We show that the addition of very small amounts of polymer inhibits this singularity in an abrupt way and gives rise, after a period of self-similar dynamics as for simple liquids, to long-lived cylindrical necks or filaments which thin exponentially in time. This abrupt change occurs when the elongation rate epsilon* becomes comparable to the inverse of the polymer relaxation time leading to a large elongational viscosity eta(E) of the dilute polymer solution.

Mini mutagenicity test: a miniaturized version of the Ames test used in a prescreening assay for point mutagenesis assessment

The bacterial reverse mutagenicity test on Salmonella typhimurium, known as the Ames test, is widely used by regulatory agencies, academic institutions and chemical companies to assess the mutagenic potential of raw compounds. Several attempts have been made to miniaturise the Ames test in order to fit the industrial constraint of screening more products at the low quantities available. The major limitation of these miniaturised versions of the Ames test lies in the impossibility to work with all the six strains used in the regular Ames test, especially with those showing a low spontaneous revertant frequency. We describe here a mini version of the regulatory Ames test protocol that allows a significant reduction of the quantity of test substance needed (300 mg) but remains applicable to all Salmonella strains used in the regulatory protocol. In a preliminary study, 10 in-house chemical compounds have been evaluated in the Mini Mutagenicity Test (MMT) together with some positive control substances. A first set of historical data obtained in 1999 as well as the predictivity and the sensitivity of the MMT are presented and compared to those of the regular Ames test.

Chlorhexidine versus povidone iodine in preventing colonization of continuous epidural catheters in children: a randomized, controlled trial

BACKGROUND

Chlorhexidine is better than povidone iodine for skin preparation before intravascular device insertion or blood culture collection, but it is not known whether chlorhexidine is superior in reducing colonization of continuous epidural catheters.

METHODS

Children requiring an epidural catheter for postoperative analgesia longer than 24 h were randomly assigned to receive skin preparation with an alcoholic solution of 0.5% chlorhexidine or an aqueous solution of 10% povidone iodine before catheter insertion. Using surgical aseptic techniques, catheters were inserted into either the lumbar or the thoracic epidural space based on the preferences of the anesthesia team, on clinical indication, or both. Immediately before epidural catheter removal, their insertion site and hub were qualitatively cultures. After their removal, the catheter tips were quantitatively cultured. Catheters were classified as colonized when their tips yielded 1,000 or more colony-forming units/ml in cultures.

RESULTS

Of 100 randomly assigned patients, 96 were evaluable. The clinical characteristics of the patients and the risk factors for infection were similar in the two groups. Catheters were kept in place for a median (range) duration of 50 (range, 21-100) h. Catheters inserted after skin preparation with chlorhexidine were one sixth as likely and less quickly to be colonized as catheters inserted after skin preparation with povidone iodine (1 of 52 catheters [0.9 per 100 catheter days] vs. 5 of 44 catheters [5.6 per 100 catheter days]; relative risk, 0.2 [95% confidence interval, 0.1-1.0]; P = 0.02). Coagulase-negative staphylococci were the only colonizing microorganisms recovered, and the skin surrounding the catheter insertion site was the origin of all the colonizing microorganisms.

CONCLUSIONS

Compared with aqueous povidone iodine, the use of alcoholic chlorhexidine for cutaneous antisepsis before epidural catheter insertion reduces the risk of catheter colonization in children.

Shear-induced first-order sponge-to-lamellar transition in a lyotropic surfactant system

We report a shear-induced sponge (L3) to lamellar (L(alpha)) transition in a surfactant system. Under a constant shear rate, after a delay time t(n) we observe random nucleation and subsequent growth of the L(alpha) phase, demonstrating that the shear-induced transition is first order. A simple argument for the energy of a two-dimensional nucleus accounts for the observed delay and its shear-rate dependence.