White Matter Atrophy and Cognitive Dysfunctions in Neuromyelitis Optica

Neuromyelitis optica (NMO) is an inflammatory disease of central nervous system characterized by optic neuritis and longitudinally extensive acute transverse myelitis. NMO patients have cognitive dysfunctions but other clinical symptoms of brain origin are rare. In the present study, we aimed to investigate cognitive functions and brain volume in NMO. The study population consisted of 28 patients with NMO and 28 healthy control subjects matched for age, sex and educational level. We applied a French translation of the Brief Repeatable Battery (BRB-N) to the NMO patients. Using SIENAx for global brain volume (Grey Matter, GM; White Matter, WM; and whole brain) and VBM for focal brain volume (GM and WM), NMO patients and controls were compared. Voxel-level correlations between diminished brain concentration and cognitive performance for each tests were performed. Focal and global brain volume of NMO patients with and without cognitive impairment were also compared. Fifteen NMO patients (54%) had cognitive impairment with memory, executive function, attention and speed of information processing deficits. Global and focal brain atrophy of WM but not Grey Matter (GM) was found in the NMO patients group. The focal WM atrophy included the optic chiasm, pons, cerebellum, the corpus callosum and parts of the frontal, temporal and parietal lobes, including superior longitudinal fascicle. Visual memory, verbal memory, speed of information processing, short-term memory and executive functions were correlated to focal WM volumes. The comparison of patients with, to patients without cognitive impairment showed a clear decrease of global and focal WM, including brainstem, corticospinal tracts, corpus callosum but also superior and inferior longitudinal fascicles. Cognitive impairment in NMO patients is correlated to the decreased of global and focal WM volume of the brain. Further studies are needed to better understand the precise origin of cognitive impairment in NMO patients, particularly in the WM

Potential efficacy of dopaminergic antidepressants in treatment resistant anergic-anhedonic depression results of the chronic anergic-anhedonic depression open trial – CADOT

IntroductionAmong treatment-resistant depression (TRD), we identified anergic-anhedonic clinical presentations (TRAD) as putatively responsive to pro-dopaminergic strategies. Based on the literature, non-selective monoamine oxidase inhibitors (MAOI) and dopamine D2 receptor agonists (D2RAG) were sequentially introduced, frequently under the coverage of a mood stabilizer. This two-step therapeutic strategy will be referred to as the Dopaminergic Antidepressant Therapy Algorithm (DATA). We describe the short and long-term outcomes of TRAD managed according to DATA guidelines.MethodOut of 52 outpatients with TRAD treated with DATA in a single expert center, 48 were included in the analysis [severity – QIDS (Quick Inventory of Depressive Symptomatology) = 16 ± 3; episode duration = 4.1 ± 2.7 years; Thase and Rush resistance stage = 2.9 ± 0.6; functioning – GAF (Global Assessment of Functioning) = 41 ± 8]. These were followed-up for a median (1st – 3rd quartile) of 4 (1–9) months before being prescribed the first dopaminergic treatment and remitters were followed up 21 (11–33) months after remission.ResultsAt the end of DATA step 1, 25 patients were in remission (QIDS <6; 52% [38–66%]). After DATA step 2, 37 patients were in remission (77% [65–89%]) to whom 5 patients with a QIDS score = 6 could be added (88% [78–97%]). Many of these patients felt subjectively remitted (GAF = 74 ± 10). There was a significant benefit to combining MAOI with D2RAG which was maintained for at least 18 months in 30 patients (79% [62–95%]).ConclusionThese results support TRAD sensitivity to pro-dopaminergic interventions. However, some clinical heterogeneities remain in our sample and suggest some improvement in the description of dopamine-sensitive form(s)

Plasma-catalytic mineralization of toluene adsorbed on CeO<SUB>2</SUB>

International audienceIn the context of coupling nonthermal plasmas with catalytic materials, CeO2 is used as adsorbent for toluene and combined with plasma for toluene oxidation. Two configurations are addressed for the regeneration of toluene saturated CeO2: (i) in plasma-catalysis (IPC); and (ii) post plasma-catalysis (PPC). As an advanced oxidation technique, the performances of toluene mineralization by the plasma-catalytic systems are evaluated and compared through the formation of CO2. First, the adsorption of 100 ppm of toluene onto CeO2 is characterized in detail. Total, reversible and irreversible adsorbed fractions are quantified. Specific attention is paid to the influence of relative humidity (RH): (i) on the adsorption of toluene on CeO2; and (ii) on the formation of ozone in IPC and PPC reactors. Then, the mineralization yield and the mineralization efficiency of adsorbed toluene are defined and investigated as a function of the specific input energy (SIE). Under these conditions, IPC and PPC reactors are compared. Interestingly, the highest mineralization yield and efficiency are achieved using the in-situ configuration operated with the lowest SIE, that is, lean conditions of ozone. Based on these results, the specific impact of RH on the IPC treatment of toluene adsorbed on CeO2 is addressed. Taking into account the impact of RH on toluene adsorption and ozone production, it is evidenced that the mineralization of toluene adsorbed on CeO2 is directly controlled by the amount of ozone produced by the discharge and decomposed on the surface of the coupling material. Results highlight the key role of ozone in the mineralization process and the possible detrimental effect of moisture

Potential for fossilization of an extremotolerant bacterium isolated from a past mars analog environment

In the context of astrobiological missions to Mars, the key question is what biosignatures to search for and how? lndigenous Martian organisms, if they existed or still exist, can be classified as extremophile per se. Following this precept the FP7-funded European MASE project (Mars Analogues for Space Exploration} is investigating various aspects of anaerobic life under Mars' extreme envrionmental conditions, including the potential for preservation over long geological time periods of certain strains. In this contribution, we report on the mineralisation and preservation of Yersinia sp. in silica and gypsum, two minerals that have been reported on Mars, in cold and anaerobic conditions, similar to Martian conditions. The organism, polyextremotolerant bacterium Yersinia sp. MASE-LG-1 (hereafter named Yersinia. sp.) was isolated from the lcelandic Graenavatn Lake, an acidic (pH3), cold and oligotrophic volcanic crater lake. These organisms have a strong tolerance to diverse Mars-like stresses (Rettberg et al., 2015). We also studied the effect of physiological status on mineralisation by exposing Yersinia to two common stresses thought to have increased du ring Mars history, desiccation and radiation. The mineralisation process has been studied using microbiological (microbial viability), morphological (scanning and transmission electron microscopy), biochemical (GC-MS, Rock-Eval) and spectroscopic (FTIR and RAMAN spectroscopy) methodologies. Based on these approaches, the potential of mineralised Yersinia sp. cells to be preserved over geological time scales is also discussed. Salient results include the fact that fossilisation in gypsum solutions is slower than in silica; not all cells were mineralised, even after 6-months in the fossilising solutions, although the FTIR, Raman and SOLID biomarker signatures were lost by this time period; Rock-Eval analysis suggests that the kerogen in the fossilised strain may not survive preservation over long geological periods, although carbon molecules preserved in fossil microbial traces up to ~3.45 Ga have been detected in the rock record

Detection of biosignatures on Mars using Raman spectroscopy: expectations and limits

The well-established presence of liquid water on the surface of Mars during the Noachian and early Hesperian periods signifies that the planet was partly habitable [1,2]. Liquid water disappeared from the surface of Mars ca. 3.5 billion years ago [2]. Nevertheless, contrary to the Early Earth, which was covered by a global ocean, Mars was probably only patchily covered by lakes or seas, not necessary connected to each other. Consequently, life may have appeared and disappeared on one, or several, place(s) without colonizing the whole planet; hence the concept of punctuated spatial and temporal habitability proposed by Westall et al (2015) [2]. In addition to making landing site selection crucial, this specificity of Mars could have limited the evolution of life to very simple microorganisms. Lack of oxygen in the atmosphere and, therefore, of an ozone layer, meant that its surface has been continuously exposed to high-energy UV radiation (down to 190 nm wavelength), deleterious for organics and responsible for the formation of hydrogen peroxide [1,3]. In the absence of a magnetic field, it is also exposed to the solar and galactic cosmic rays that reach the surface and the near subsurface [4]. In addition to making the surface of Mars presently highly inhospitable, this radiative environment may have altered inorganic and organic biosignatures with time. Here we present the results of experiments to study the preservation of different types of representative biosignatures and their detectability using Raman spectroscopy under Mars conditions. This method, able to analyse both organic and mineral phases and compatible with in situ exploration, is particularly relevant to search for past or present traces of life and equipped the current NASA Mars 2020 and future ESA ExoMars rovers. For ancient traces of life, we used terrestrial Precambrian microfossils as a reference. We showed that their biogenecity is difficult to demonstrate unambiguously using Raman spectroscopy alone and that such traces of life would be probably too subtle to be detected in situ on Mars [5,6]. For recent traces of life, where biomolecules have not been transformed into kerogen with time and metamorphism, we performed experiments in the laboratories where we studied the degradation of the Raman signal of different pigments and molecules during UV and cosmic rays irradiation. In particular, an original Raman system, called RAMSESS (RAMan SpEctroscopy for in Situ Studies), was developed at CNRS CEMHTI-Pelletron, Orléans, France, to study the changes in the Raman signal of different minerals and organic molecules in situ within the irradiation chamber (see Fig. 1) [7]. These experiments are very complementary to those obtained during the BIOMEX experiment on-board the ISS [8,9]. [1] J.-P. Bibring, Y. Langevin, J. F. Mustard, F. Poulet, R. Arvidson, A. Gendrin, B. Gondet, N. Mangold, P. Pinet, F. Forget and the OMEGA team, Science, 312, 400 (2006). [2] F. Westall, F. Foucher, N. Bost, M. Bertrand, D. Loizeau, J. L. Vago, G. Kminek, F. Gaboyer, K. A. Campbell, J.-G. Bréhéret, P. Gautret and C. S. Cockell, Astrobiology, 15, 998 (2015). [3] M. A. Bullock, C. R. Stoker, C. P. McKay and A. P. Zent, Icarus, 107, 142 (1994). [4] G. de Angelis, M. S. Clowdsley, R. C. Singleterry and J. W. Wilson, Advances in Space Research, 34, 1328 (2004). [5] F. Foucher and F. Westall, Astrobiology, 13:1, 57 (2013). [6] F. Foucher, M. R. Ammar and F. Westall, Journal of Raman Spectroscopy, 46, 873 (2015). [7] A. Canizarès, F. Foucher, M. Baqué, J.-P. de Vera, T. Sauvage, O. Wendling, A. Bellamy, P. Sigot, T. Georgelin, P. Simon and F. Westall, Applied Spectroscopy, 76, 723 (2022). [8] J.-P. de Vera, M. Alawi, T. Backhaus, M. Baqué, D. Billi, U. Böttger, T. Berger, M. Bohmeier, C. Cockell, R. Demets, R. de la Torre Noetzel, H. Edwards, A. Elsaesser, C. Fagliarone, A. Fiedler, B. Foing, F. Foucher, J. Fritz, F. Hanke, T. Herzog, G. Horneck, H.-W. Hübers, B. Huwe, J. Joshi, N. Kozyrovska, M. Kruchten, P. Lasch, N. Lee, S. Leuko, T. Leya, A. Lorek, J. Martinez-Frias, J. Meessen, S. Moritz, R. Moeller, K. Olsson-Francis, S. Onofri, S. Ott, C. Pacelli, O. Podolich, E. Rabbow, G. Reitz, P. Rettberg, O. Reva, L. Rothschild, L. G. Sancho, D. Schulze-Makuch, L. Selbmann, P. Serrano, U. Szewzyk, C. Verseux, J. Wadsworth, D. Wagner, F. Westall, D. Wolter and L., Zucconi, Astrobiology, 19:2, 145 (2019). [9] M. Baqué, T. Backhaus, J. Meeßen, F. Hanke, U. Böttger, N. Ramkissoon, K. Olsson-Francis, M. Baumgärtner, D. Billi, A. Cassaro, R. de la Torre Noetzel, R. Demets, H. Edwards, P. Ehrenfreund, A. Elsaesser, B. Foing, F. Foucher, B. Huwe, J. Joshi, N. Kozyrovska, P. Lasch, N. Lee, S. Leuko, S. Onofri, S. Ott, C. Pacelli, E. Rabbow, L. Rothschild, D. Schulze-Makuch, L. Selbmann, P. Serrano, U. Szewzyk, C. Verseux, D. Wagner, F. Westall, L. Zucconi and J.-P. P. de Vera., Science Advances, 8, 7412 (2022

In Situ Raman Spectroscopy Monitoring of Material Changes During Proton Irradiation

Organic molecules are prime targets in the search for life on other planetary bodies in the Solar System. Understanding their preservation potential and detectability after ionic irradiation, with fluences potentially representing those received for several millions to billions of years at Mars or in interplanetary space, is a crucial goal for astrobiology research. In order to be able to perform in situ characterization of such organic molecules under ionic irradiation in the near future, a feasibility experiment was performed with polymer test samples to validate the optical configuration and the irradiation chamber geometry. We present here a Raman in situ investigation of the evolution of a series of polymers during proton irradiation. To achieve this goal, a new type of Raman optical probe was designed, which documented that proton irradiation (with a final fluence of 3e14 at/cm²) leads to an increase in the background level of the signal, potentially explained by the scission of the polymeric chains and by atom displacements creating defects in the materials. To improve the setup further, a micro-Raman probe and a temperature-controlled sample holder are under development to provide higher spectral and spatial resolutions (by reducing the depth of field and laser spot size), to permit Raman mapping as well as to avoid any thermal effects