Subsequent and simultaneous electrophysiological investigation of the retina and the visual cortex in neurodegenerative and psychiatric diseases: what are the forecasts for the medicine of tomorrow?

Visual electrophysiological deficits have been reported in neurodegenerative disorders as well as in mental disorders. Such alterations have been mentioned in both the retina and the cortex, notably affecting the photoreceptors, retinal ganglion cells (RGCs) and the primary visual cortex. Interestingly, such impairments emphasize the functional role of the visual system. For this purpose, the present study reviews the existing literature with the aim of identifying key alterations in electroretinograms (ERGs) and visual evoked potentials electroencephalograms (VEP-EEGs) of subjects with neurodegenerative and psychiatric disorders. We focused on psychiatric and neurodegenerative diseases due to similarities in their neuropathophysiological mechanisms. Our research focuses on decoupled and coupled ERG/VEP-EEG results obtained with black-and-white checkerboards or low-level visual stimuli. A decoupled approach means recording first the ERG, then the VEP-EEG in the same subject with the same visual stimuli. The second method means recording both ERG and VEP-EEG simultaneously in the same participant with the same visual stimuli. Both coupled and decoupled results were found, indicating deficits mainly in the N95 ERG wave and the P100 VEP-EEG wave in Parkinson’s, Alzheimer’s, and major depressive disorder. Such results reinforce the link between the retina and the visual cortex for the diagnosis of psychiatric and neurodegenerative diseases. With that in mind, medical devices using coupled ERG/VEP-EEG measurements are being developed in order to further investigate the relationship between the retina and the visual cortex. These new techniques outline future challenges in mental health and the use of machine learning for the diagnosis of mental disorders, which would be a crucial step toward precision psychiatry

MALDI-TOF MS Profiling of Annonaceous Acetogenins in Annona muricata Products for Human Consumption

Annonaceous acetogenins are proposed as environmental neurotoxicants consumed through medicinal and alimentary habits and responsible for atypical parkinsonian syndromes observed in tropical areas. Potential sources of exposure still have to be determined, as, to date, only a few batches of products for human consumption were searched for these compounds. To assess the presence of acetogenins, we propose a fast, sensitive and accurate method of screening, using MALDI-TOF MS, with minimal sample preparation. Development of the technique is discussed. Its application to leaves of herbal tea, pulp and bottled nectar of Annona muricata is presented

MALDI-TOF MS Profiling of Annonaceous Acetogenins in Annona muricata Products for Human Consumption

Annonaceous acetogenins are proposed as environmental neurotoxicants consumed through medicinal and alimentary habits and responsible for atypical parkinsonian syndromes observed in tropical areas. Potential sources of exposure still have to be determined, as, to date, only a few batches of products for human consumption were searched for these compounds. To assess the presence of acetogenins, we propose a fast, sensitive and accurate method of screening, using MALDI-TOF MS, with minimal sample preparation. Development of the technique is discussed. Its application to leaves of herbal tea, pulp and bottled nectar of Annona muricata is presented

Monitoring enzyme-catalyzed production of glucosamine-6P by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry: a new enzymatic assay for glucosamine-6P synthase

International audienc

The patinas of the DogoneTellem statuary: A new vision through physico-chemical analyses

Numerous African art objects collected in the course of colonial or ethnological expeditions during the 20th century are partially or completely covered with a so-called ‘‘patina’’. These patinas have been formed during religious and ritual ceremonies, where different substances have been spread out at the surface of the objects. The anthropomorphic statuettes from the Dogon culture are well-known examples of this kind of practice. A better understanding of the chemical composition of these patinas could explain details of the ceremonial practices realized throughout the centuries. An important challenge is to extract unequivocal information about the original constituents of these patinas, and the techniques used for their application on ritual objects. The Dogon statuary can be divided into three periods. The oldest one, before 1350 A.D., is called the Tellem period, according to the name of the people who lived in this area before the arrival of the Dogon. The most recent, after 1650 A.D., is the Dogon period. These two periods are separated by an intermediary period, where the attribution to the Tellem or to the Dogon cultures is difficult. During our study, we have worked on the patina of 12 Dogon artifacts from these three different periods. In this paper, we present the results obtained for two representative objects, one of the Tellem period and one of the Dogon period. The aim is to access the chemical composition of the patinas and to see if they can be compared to ethnological reports, as is often done in the literature on ethnological studies. Chemical imaging techniques, based on the combination of microscopy and spectroscopy, are well suited to study both the composition and the spatial organization of heterogeneous complex mixtures of organic and inorganic matter. Time-of-flight secondary ion mass spectrometry (ToF-SIMS), followed by scanning electron microscopy with energy dispersive X-ray analysis (SEM-EDS), and synchrotron radiation-based Fourier transform infrared microscopy (SR-mFTIR) have been applied to non-destructive analyses of micro-samples of the patinas of several Dogon statuettes. A very careful preparation, using ultramicrotomy on embedded samples, allowed us to perform successively all these measurements on a single fragment. Comparison and superposition of the different chemical images lead us to identify minerals (clays, quartz and calcium carbonate), and different organic products (proteins, starch, lipids), as well as to map their spatial distribution. The patina of the most recent statuettes presents a stratigraphy which can be related to successive uses of the objects for ritual purposes, and the results are in agreement with the ethnological reports. For the Tellem objects, the significant quantity of minerals and the lack of stratigraphy suggest that the patina was deposited according to a different recipe. This difference suggests the existence of a diversity of rituals that are more extensive than that described by the ethnologists

Validation of the French version of the Cannabis Use Disorder Identification Test—Revised and comparison with the Cannabis Abuse Screening Test for screening cannabis use disorder in a psychiatric sample

International audienceIntroduction: Several questionnaires have been developed for screening cannabis use disorder in clinical populations, but very few studies have compared the screening abilities of the different instruments. Here, we aimed to confirm the psychometric properties of a French version of the Cannabis Use Disorder Identification Test—Revised (CUDIT-R), and to compare its screening abilities with those of the Cannabis Abuse Screening Test (CAST), in subjects consulting in mental health settings. Methods: Two hundred and thirteen cannabis smokers who sought treatment for any type of mental disorder, recruited in four French centres, completed the French CUDIT-R (CUDIT-R-Fr) and the full version of the CAST, and were assessed for Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition criteria of cannabis use disorder by an addiction specialist. They were retested with the CUDIT-R-Fr after approximately a week. The factorial construct validity, internal consistency and test–retest reliability of the CUDIT-R-Fr were assessed. The compared sensitivity and specificity of the CAST and CUDIT-R-Fr were explored, using the clinician assessment as the reference. Results: The French CUDIT-R showed a good internal consistency (Cronbach's alpha = 0.89) and an excellent test–retest reliability (ρ = 0.97). The sensitivity and specificity for screening cannabis use disorder were 0.81 and 0.77 for the CUDIT-R, and 0.92 and 0.63 for the CAST, respectively. Conclusions: Based on the recommended cut-offs, the CAST appeared more sensitive, while the CUDIT-R was more specific, for screening cannabis use disorder in a population of cannabis users with heterogeneous types of mental health disorders