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International audience; Background and purpose: Studies on long-term nonmotor outcomes of subthalamic nucleus stimulation in Parkinson disease (PD) are scarce. This study reports on very long-term non-motor and motor outcomes in one of the largest cohorts of people with advanced PD, treated for >10 years with subthalamic nucleus stimulation. The main outcome was to document the evolution of independence in activities of daily living. The secondary outcomes were to measure the change in quality of life, as well as non-motor and motor outcomes.Methods: Patients were studied preoperatively, at 1 year, and beyond 10 years after subthalamic stimulation with an established protocol including motor, non-motor, and neuropsychological assessments.Results: Eighty-five people with PD were included. Independence scores in the off-medication condition (measured with the Schwab & England Activities of Daily Living Scale) as well as quality of life (measured with the Parkinson's Disease Questionnaire [PDQ]-37) remained improved at longest follow-up compared to preoperatively (respectively, p < 0.001, p = 0.015). Cognitive scores, measured with the Mattis Dementia Rating Scale, significantly worsened compared to before and 1 year after surgery (p < 0.001), without significant change in depression, measured with the Beck Depression Inventory. Motor fluctuations, dyskinesias, and off dystonia remained improved at longest follow-up (p < 0.001), with a significant reduction in dopaminergic treatment (45%, p < 0.001).Conclusions: This study highlights the long-term improvement of subthalamic stimulation on independence and quality of life, despite the progression of disease and the occurrence of levodopa-resistant symptoms.

In eukaryotes and in archaea late steps of translation initiation involve the two initiation factors e/aIF5B and e/aIF1A. In eukaryotes, the role of eIF5B in ribosomal subunit joining is established and structural data showing eIF5B bound to the full ribosome were obtained. To achieve its function, eIF5B collaborates with eIF1A. However, structural data illustrating how these two factors interact on the small ribosomal subunit have long been awaited. The role of the archaeal counterparts, aIF5B and aIF1A, remains to be extensively addressed. Here, we study the late steps of Pyrococcus abyssi translation initiation. Using in vitro reconstituted initiation complexes and light scattering, we show that aIF5B bound to GTP accelerates subunit joining without the need for GTP hydrolysis. We report the crystallographic structures of aIF5B bound to GDP and GTP and analyze domain movements associated to these two nucleotide states. Finally, we present the cryo-EM structure of an initiation complex containing 30S bound to mRNA, Met-tRNAiMet, aIF5B and aIF1A at 2.7 Å resolution. Structural data shows how archaeal 5B and 1A factors cooperate to induce a conformation of the initiator tRNA favorable to subunit joining. Archaeal and eukaryotic features of late steps of translation initiation are discussed.

Aberrantly slow mRNA translation leads to ribosome stalling and subsequent collision with the trailing neighbor. Ribosome collisions have recently been shown to act as stress sensors in the cell, with the ability to trigger stress responses balancing survival and apoptotic cell-fate decisions depending on the stress level. However, we lack a molecular understanding of the reorganization of translation processes over time in mammalian cells exposed to an unresolved collision stress. Here we visualize the effect of a persistent collision stress on translation usingin situcryo electron tomography. We observe that low dose anisomycin collision stress leads to the stabilization of Z-site bound tRNA on elongating 80S ribosomes, as well as to the accumulation of an off-pathway 80S complex possibly resulting from collision splitting events. We visualize collided disomesin situ, occurring on compressed polysomes and revealing a stabilized geometry involving the Z-tRNA and L1 stalk on the stalled ribosome, and eEF2 bound to its collided rotated-2 neighbor. In addition, non-functional post-splitting 60S complexes accumulate in the stressed cells, indicating a limiting Ribosome associated Quality Control clearing rate. Finally, we observe the apparition of tRNA-bound aberrant 40S complexes shifting with the stress timepoint, suggesting a succession of different initiation inhibition mechanisms over time. Altogether, our work visualizes the changes of translation complexes under persistent collision stress in mammalian cells, indicating how perturbations in initiation, elongation and quality control processes contribute to an overall reduced protein synthesis.SummaryUsingin situcryo electron tomography we visualized the reorganization of mammalian translation processes during a persistent collision stress.

Background: Management of extracranial internal carotid artery steno-occlusive lesion during endovascular therapy remains debated. Stent occlusion within 24 hours of endovascular therapy is a frequent event after acute carotid artery stenting, and we currently lack large population results. We investigated the incidence, predictors, and clinical impact of stent occlusion after acute carotid artery stenting in current clinical practice. Methods: Patients treated by endovascular therapy with acute carotid artery stenting between 2015 and 2019 in 5 large-volume endovascular-capable centers were retrospectively analyzed. Patients were separated in 2 groups according to the stent patency at 24 hours after carotid artery stenting. We compared baseline characteristics, treatment modalities, and clinical outcome depending on 24-hour stent patency. Primary end point was favorable outcome, defined as a modified Rankin Scale score 0–2 at 3 months. Results: A stent occlusion was observed in 47/225 patients (20.9%). Patients with stent patency had a lower baseline National Institutes of Health Stroke Scale (median [interquartile range]: 13 [7–17] versus 18 [12–21]) and had more often stroke of atherothrombotic origin (77.0% versus 53.2%). A higher stent patency rate was found for patients treated with P2Y 12 antagonists at the acute phase (odds ratio [OR]‚ 2.95 [95% CI‚ 1.10–7.91]; P =0.026) and treated with angioplasty (OR‚ 2.42 [95% CI‚ 1.24–4.67]; P =0.008). A better intracranial angiographic reperfusion was observed in patients with 24-hour stent patency compared with patients without stent patency (OR‚ 8.38 [95% CI‚ 3.07–22.78]; P P P =0.009). Conclusions: One out of 5 patients treated with carotid artery stenting during endovascular therapy presented a stent occlusion within 24 hours. This event was associated with worse functional outcome. Stroke etiology, P2Y 12 antagonist administration, quality of intracranial reperfusion, and angioplasty were associated with 24-hour stent patency.

Small-angle X-ray scattering (SAXS) has become an indispensable tool in structural biology, complementing atomic-resolution techniques. It is sensitive to the electron-density difference between solubilized biomacromolecules and the buffer, and provides information on molecular masses, particle dimensions and interactions, low-resolution conformations and pair distance-distribution functions. When SAXS data are recorded at multiple contrasts, i.e. at different solvent electron densities, it is possible to probe, in addition to their overall shape, the internal electron-density profile of biomacromolecular assemblies. Unfortunately, contrast-variation SAXS has been limited by the range of solvent electron densities attainable using conventional co-solutes (for example sugars, glycerol and salt) and by the fact that some biological systems are destabilized in their presence. Here, SAXS contrast data from an oligomeric protein and a protein–RNA complex are presented in the presence of iohexol and Gd-HPDO3A, two electron-rich molecules that are used in biomedical imaging and that belong to the families of iodinated and lanthanide-based complexes, respectively. Moderate concentrations of both molecules allowed solvent electron densities matching those of proteins to be attained. While iohexol yielded higher solvent electron densities (per mole), it interacted specifically with the oligomeric protein and precipitated the protein–RNA complex. Gd-HPDO3A, while less efficient (per mole), did not disrupt the structural integrity of either system, and atomic models could be compared with the SAXS data. Due to their elevated solubility and electron density, their chemical inertness, as well as the possibility of altering their physico-chemical properties, lanthanide-based complexes represent a class of molecules with promising potential for contrast-variation SAXS experiments on diverse biomacromolecular systems.

BACKGROUND: HIT-SKK protocol is used for the treatment of low risk medulloblastomas in young children with the aim of eliminating cranial irradiation and its long-term side effects, in particular neuropsychological (NP) sequelae. This therapy includes IV and intraventricular (ITV) methotrexate (MTX) potentially responsible for leukoencephalopathy (LE) and neurocognitive disorders.The objectives are to describe the risk factors and the course of LE, and to investigate its impact on long-term neurocognitive and behavioural outcome. METHODS: A French retrospective, multicenter study including 35 children under 5 years of age, treated between 2009 and 2017, with a median follow up of 72 months. All follow-up MRIs including assessment of the severity of the LE (Fazekas and CTCAE grading) and all NP evaluations were centrally rewieved. RESULTS: 25/34 evaluable patients presented a LE during follow up, in a median delay of 2 months (1 - 17 months) after the start of chemotherapy. Grade 2 and 3 abnormalities were correlated with higher cumulative dose of ITV -MTX (p=0,01). Full Scale IQ (FSIQ) and Wechsler indexes were in the average or low average of the reference population. FSIQ was deficient in 7/20 evaluable patients. Processing speed (PSI) was the most frequently impaired neurocognitive domain: 9/20 patients with borderline or very low score, all having received a significantly higher cumulative dose of ITV-MTX (p=0,04). A decrease in overall NP scores was observed in patients for whom grade 2 or 3 LE persisted at the end of follow-up with an average FSIQ estimated at 82.1 (SD 16.9) versus 94.2 (SD 20.6). This decrease was significant for PSI (p=0,049). LE and neurocognitive impairments were not correlated with a younger age at diagnosis. CONCLUSION: This study confirmed the responsibility of MTX, and in particular ITV-MTX therapy in the onset and, most often, persistence of LE and its association with neurocognitive disorders.

Background and Purpose: Approximately half of the patients with acute ischemic stroke due to anterior circulation large vessel occlusion do not achieve functional independence despite successful reperfusion. We aimed to determine influence of reperfusion strategy (bridging therapy, intravenous thrombolysis alone, or mechanical thrombectomy alone) on clinical outcomes in this population. Methods: From ongoing, prospective, multicenter, observational Endovascular Treatment in Ischemic Stroke registry in France, all patients with anterior circulation large vessel occlusion who achieved successful reperfusion (modified Thrombolysis in Cerebral Infarction 2b-3) following reperfusion therapy were included. Primary end point was favorable outcome, defined as 90-day modified Rankin Scale score ≤2. Patient groups were compared using those treated with bridging therapy as reference. Differences in baseline characteristics were reduced after propensity score-matching, with a maximum absolute standardized difference of 14% for occlusion site. Results: Among 1872 patients included, 970 (51.8%) received bridging therapy, 128 (6.8%) received intravenous thrombolysis alone, and the remaining 774 (41.4%) received MT alone. The rate of favorable outcome was comparable between groups. Excellent outcome (90-day modified Rankin Scale score 0–1) was achieved more frequently in the bridging therapy group compared with the MT alone (odds ratio after propensity score-matching, 0.70 [95% CI, 0.50–0.96]). Regarding safety outcomes, hemorrhagic complications were similar between the groups, but 90-day mortality was significantly higher in the MT alone group compared with the bridging therapy group (odds ratio, 1.60 [95% CI, 1.09–2.37]). Conclusions: This real-world observational study of patients with anterior circulation large vessel occlusion demonstrated a similar rate of favorable outcome following successful reperfusion with different therapeutic strategies. However, our results suggest that bridging therapy compared with MT alone is significantly associated with excellent clinical outcome and lower mortality. REGISTRATION: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT03776877.

Recently, we observed the first example of a left‐handed G‐quadruplex structure formed by natural DNA, named Z‐G4 . We analysed the Z‐G4 structure and inspected its primary 28‐nt sequence in order to identify motifs that convey the unique left‐handed twist. Using circular dichroism spectroscopy, NMR spectroscopy, and X‐ray crystallography, we revealed a minimal sequence motif of 12 nt (GTGGTGGTGGTG) for formation of the left‐handed DNA G‐quadruplex, which is found to be highly abundant in the human genome. A systematic analysis of thymine loop mutations revealed a moderate sequence tolerance, which would further broaden the space of sequences prone to left‐handed G‐quadruplex formation. NRF (Natl Research Foundation, S’pore) MOE (Min. of Education, S’pore) Accepted version

Human 4-hydroxyphenylpyruvate dioxygenase-like (HPDL) is a putative iron-containing non-heme oxygenase of unknown specificity and biological significance. We report 25 families containing 34 individuals with neurological disease associated with biallelic HPDL variants. Phenotypes ranged from juvenile-onset pure hereditary spastic paraplegia to infantile-onset spasticity and global developmental delays, sometimes complicated by episodes of neurological and respiratory decompensation. Variants included bona fide pathogenic truncating changes, although most were missense substitutions. Functionality of variants could not be determined directly as the enzymatic specificity of HPDL is unknown; however, when HPDL missense substitutions were introduced into 4-hydroxyphenylpyruvate dioxygenase (HPPD, an HPDL orthologue), they impaired the ability of HPPD to convert 4-hydroxyphenylpyruvate into homogentisate. Moreover, three additional sets of experiments provided evidence for a role of HPDL in the nervous system and further supported its link to neurological disease: (i) HPDL was expressed in the nervous system and expression increased during neural differentiation; (ii) knockdown of zebrafish hpdl led to abnormal motor behaviour, replicating aspects of the human disease; and (iii) HPDL localized to mitochondria, consistent with mitochondrial disease that is often associated with neurological manifestations. Our findings suggest that biallelic HPDL variants cause a syndrome varying from juvenile-onset pure hereditary spastic paraplegia to infantile-onset spastic tetraplegia associated with global developmental delays.

G-quadruplex (G4) DNA structures with a left-handed backbone progression have unique and conserved structural features. Studies on sequence dependency of the structures revealed the prerequisites and some minimal motifs required for left-handed G4 formation. To extend the boundaries, we explore the adaptability of left-handed G4s towards the existence of bulges. Here we present two X-ray crystal structures and an NMR solution structure of left-handed G4s accommodating one, two and three bulges. Bulges in left-handed G4s show distinct characteristics as compared to those in right-handed G4s. The elucidation of intricate structural details will help in understanding the possible roles and limitations of these unique structures. Ministry of Education (MOE) Nanyang Technological University National Research Foundation (NRF) Published version Singapore National Research Foundation Investigatorship [NRF-NRFI2017-09]; Singapore Ministry of Education Academic Research Fund Tier 2 [MOE2015-T2- 1092]; Nanyang Technological University (NTU Singapore) grants (to A.T.P.). Funding for open access charge: Nanyang Technological University.

Contains fulltext : 237881.pdf (Publisher’s version ) (Open Access) Human 4-hydroxyphenylpyruvate dioxygenase-like (HPDL) is a putative iron-containing non-heme oxygenase of unknown specificity and biological significance. We report 25 families containing 34 individuals with neurological disease associated with biallelic HPDL variants. Phenotypes ranged from juvenile-onset pure hereditary spastic paraplegia to infantile-onset spasticity and global developmental delays, sometimes complicated by episodes of neurological and respiratory decompensation. Variants included bona fide pathogenic truncating changes, although most were missense substitutions. Functionality of variants could not be determined directly as the enzymatic specificity of HPDL is unknown; however, when HPDL missense substitutions were introduced into 4-hydroxyphenylpyruvate dioxygenase (HPPD, an HPDL orthologue), they impaired the ability of HPPD to convert 4-hydroxyphenylpyruvate into homogentisate. Moreover, three additional sets of experiments provided evidence for a role of HPDL in the nervous system and further supported its link to neurological disease: (i) HPDL was expressed in the nervous system and expression increased during neural differentiation; (ii) knockdown of zebrafish hpdl led to abnormal motor behaviour, replicating aspects of the human disease; and (iii) HPDL localized to mitochondria, consistent with mitochondrial disease that is often associated with neurological manifestations. Our findings suggest that biallelic HPDL variants cause a syndrome varying from juvenile-onset pure hereditary spastic paraplegia to infantile-onset spastic tetraplegia associated with global developmental delays.

Archaeal translation initiation occurs within a macromolecular complex containing the small ribosomal subunit (30S) bound to mRNA, initiation factors aIF1, aIF1A and the ternary complex aIF2:GDPNP:Met-tRNAiMet. Here, we determine the cryo-EM structure of a 30S:mRNA:aIF1A:aIF2:GTP:Met-tRNAiMet complex from Pyrococcus abyssi at 3.2 Å resolution. It highlights archaeal features in ribosomal proteins and rRNA modifications. We find an aS21 protein, at the location of eS21 in eukaryotic ribosomes. Moreover, we identify an N-terminal extension of archaeal eL41 contacting the P site. We characterize 34 N4-acetylcytidines distributed throughout 16S rRNA, likely contributing to hyperthermostability. Without aIF1, the 30S head is stabilized and initiator tRNA is tightly bound to the P site. A network of interactions involving tRNA, mRNA, rRNA modified nucleotides and C-terminal tails of uS9, uS13 and uS19 is observed. Universal features and domain-specific idiosyncrasies of translation initiation are discussed in light of ribosomal structures from representatives of each domain of life., Coureux et al. describe a cryo-EM structure of a 30S initiation complex of Pyrococcus abyssi at 3.2Å resolution. The structure uncovers a novel archaeal ribosomal protein aS21, N-terminal extension of eL41 and brings insights into base modifications of the rRNA.

ObjectiveTo describe neuroimaging findings and to report the epidemiologic and clinical characteristics of patients with coronavirus disease 2019 (COVID-19) with neurologic manifestations.MethodsIn this retrospective multicenter study (11 hospitals), we included 64 patients with confirmed COVID-19 with neurologic manifestations who underwent a brain MRI.ResultsThe cohort included 43 men (67%) and 21 women (33%); their median age was 66 (range 20–92) years. Thirty-six (56%) brain MRIs were considered abnormal, possibly related to severe acute respiratory syndrome coronavirus. Ischemic strokes (27%), leptomeningeal enhancement (17%), and encephalitis (13%) were the most frequent neuroimaging findings. Confusion (53%) was the most common neurologic manifestation, followed by impaired consciousness (39%), presence of clinical signs of corticospinal tract involvement (31%), agitation (31%), and headache (16%). The profile of patients experiencing ischemic stroke was different from that of other patients with abnormal brain imaging: the former less frequently had acute respiratory distress syndrome (p= 0.006) and more frequently had corticospinal tract signs (p= 0.02). Patients with encephalitis were younger (p= 0.007), whereas agitation was more frequent for patients with leptomeningeal enhancement (p= 0.009).ConclusionsPatients with COVID-19 may develop a wide range of neurologic symptoms, which can be associated with severe and fatal complications such as ischemic stroke or encephalitis. In terms of meningoencephalitis involvement, even if a direct effect of the virus cannot be excluded, the pathophysiology seems to involve an immune or inflammatory process given the presence of signs of inflammation in both CSF and neuroimaging but the lack of virus in CSF.ClinicalTrials.gov identifierNCT04368390.

International audience; Translation initiation (TI) allows accurate selection of the initiation codon on a messenger RNA (mRNA) and defines the reading frame. In all domains of life, translation initiation generally occurs within a macromolecular complex made up of the small ribosomal subunit, the mRNA, a specialized methionylated initiator tRNA, and translation initiation factors (IFs). Once the start codon is selected at the P site of the ribosome and the large subunit is associated, the IFs are released and a ribosome competent for elongation is formed. However, even if the general principles are the same in the three domains of life, the molecular mechanisms are different in bacteria, eukaryotes, and archaea and may also vary depending on the mRNA. Because TI mechanisms have evolved lately, their studies bring important information about the evolutionary relationships between extant organisms. In this context, recent structural data on ribosomal complexes and genome-wide studies are particularly valuable. This review focuses on archaeal translation initiation highlighting its relationships with either the eukaryotic or the bacterial world. Eukaryotic features of the archaeal small ribosomal subunit are presented. Ribosome evolution and TI mechanisms diversity in archaeal branches are discussed. Next, the use of leaderless mRNAs and that of leadered mRNAs having Shine-Dalgarno sequences is analyzed. Finally, the current knowledge on TI mechanisms of SD-leadered and leaderless mRNAs is detailed.

Background and Purpose: Although the efficacy of endovascular treatment (EVT) in patients with anterior circulation ischemic stroke (AIS) is well documented, early neurological deterioration after EVT remains a serious issue associated with poor outcome. Besides obvious causes, such as lack of reperfusion, procedural complications, or parenchymal hemorrhage, early neurological deterioration may remain unexplained (UnEND). Our aim was to investigate predictors of UnEND after EVT in patients with AIS. Methods: Patients who underwent EVT for AIS, with an initial National Institutes of Health Stroke Scale score >5, Alberta Stroke Program Early CT Score ≥6, and included in a multicenter prospective observational registry were analyzed. Predictors of UnEND, defined as ≥4-point increase in the National Institutes of Health Stroke Scale score between baseline and day 1 after EVT, were determined via center-adjusted analyses. Results: Among the 1925 included in the analysis, 128 UnEND (6.6%) were recorded. In multivariate analysis, predictors of UnEND were diabetes mellitus (odds ratio [OR], 2.17 [95% CI, 1.32–3.56]), prestroke modified Rankin Scale score ≥2 (OR, 2.22 [95% CI, 1.09–4.55]), general anesthesia (OR, 2.55 [95% CI, 1.51–4.30]), admission systolic blood pressure (OR, 1.10 [95% CI, 1.01–1.20]), age (OR, 1.38 [95% CI, 1.14–1.67]), number of passes (OR, 1.16 [95% CI, 1.04–1.28]), direct admission or not to a comprehensive stroke center (OR, 0.49 [95% CI, 0.30–0.81]), and initial National Institutes of Health Stroke Scale score (OR, 0.65 [95% CI, 0.52–0.81]). Conclusions: Severely impaired AIS patients with nonmodifiable factors are more likely to develop UnEND. Some modifiable predictors of UnEND such as the number of EVT passes could be the object of improvement in AIS management.

Background and Purpose: The best anesthetic management for mechanical thrombectomy of large vessel occlusion strokes is still uncertain and could impact the quality of reperfusion and clinical outcome. We aimed to compare the efficacy and safety outcomes between local anesthesia (LA) and conscious sedation in a large cohort of acute ischemic stroke patients with anterior circulation large vessel occlusion strokes treated with mechanical thrombectomy in current, everyday clinical practice. Methods: Patients undergoing mechanical thrombectomy for anterior large vessel occlusion strokes at 4 comprehensive stroke centers in France between January 1, 2018, and December 31, 2018, were pooled from the ongoing prospective multicenter observational Endovascular Treatment in Ischemic Stroke Registry in France. Intention-to-treat and per-protocol analyses were used. Results: Among the included 1034 patients, 762 were included in the conscious sedation group and 272 were included in the LA group. In the propensity score matched cohort, the rate of favorable outcome (90-day modified Rankin Scale score 0–2) was significantly lower in the LA group than in the conscious sedation group (40.0% versus 52.0%, matched relative risk=0.76 [95% CI, 0.60–0.97]), as well as the rate of successful reperfusion (modified Thrombolysis in Cerebral Infarction grade 2b–3; 76.6% versus 87.1%; matched relative risk=0.88 [95% CI, 0.79–0.98]). There was no difference in procedure time between the 2 groups. In the inverse probability of treatment weighting-propensity score-adjusted cohort, similar significant differences were found for favorable outcomes and successful reperfusion. In inverse probability of treatment weighting-propensity score-adjusted cohort, a higher rate of 90-day mortality and a lower parenchymal hematoma were observed after LA. The sensitivity analysis restricted to our per-protocol sample provided similar results in the matched- and inverse probability of treatment weighting-propensity cohorts. Conclusions: In the Endovascular Treatment in Ischemic Stroke registry mainly included patients in early time window (

International audience; Polypeptides containing β-amino acids are attractive tools for the design of novel proteins having unique properties of medical or industrial interest. Incorporation of β-amino acids in vivo requires the development of efficient aminoacyl-tRNA synthetases specific of these non-canonical amino acids. Here, we have performed a detailed structural and biochemical study of the recognition and use of β3-Met by Escherichia coli methionyl-tRNA synthetase (MetRS). We show that MetRS binds β3-Met with a 24-fold lower affinity but catalyzes the esterification of the non-canonical amino acid onto tRNA with a rate lowered by three orders of magnitude. Accurate measurements of the catalytic parameters required careful consideration of the presence of contaminating α-Met in β3-Met commercial samples. The 1.45 Å crystal structure of the MetRS: β3-Met complex shows that β3-Met binds the enzyme essentially like α-Met, but the carboxylate moiety is mobile and not adequately positioned to react with ATP for aminoacyl adenylate formation. This study provides structural and biochemical bases for engineering MetRS with improved β3-Met aminoacylation capabilities.

Objectives: To describe the outcome of primary meningeal sarcoma (PMS) in a pediatric population. Methods: We conducted a retrospective study on patients harbouring a PMS based on the French registry of paediatric tumours. Questionnaires were sent to all French paediatric oncologists. Data on patient characteristics and treatments were collected. Pathology and imaging were centrally reviewed. Results: Between August 1989 and May 2010, 12 patients from 6 French centres, aged 3 months to 14.5 years (mean: 3.3 years) were treated for a PMS. Mean follow-up was 12 years (range: 3 months to 24 years). Tumour locations were: frontal (3), parieto-occipital (2), parietal (1), temporal (1), occipital (1), thalamic (1), pontocerebellar angle (1), cerebellar tentorium (1), ambient cistern (1). No metastasis was observed. The first-line treatment was surgery in 10 cases, chemotherapy in 2. Resection was total in 6 cases, partial in 6. Central pathology review concluded to: high-grade undifferentiated sarcoma (8), chondrosarcoma (2), fibrosarcoma (1), myxoid desmoplastic tumour (1). Seven tumours were smaller than 5 cm in size. Eleven patients received 2 to 10 courses of chemotherapy (median: 5) but no response was observed. Four out of 6 patients for whom a total resection was performed were still alive at time of study, compared to 2 when only partial resection was possible. Four out of 6 patients who received radiotherapy are still alive, compared to 1 out of 4 patients without radiotherapy. The 5-year Event-Free Survival (EFS) and Overall Survival (OS) rates were 50%. The median EFS in case of total resection was 39 months versus 16 months in case of partial resection. Neither correlation was found between tumour size and location or between age at diagnosis and EFS/OS. Conclusions: We report the first multicentre case series describing clinical, radiological presentation and outcome of PMS in children. In this short series of very rare tumours, age and tumour size did not seem to be prognostic factors. Total resection and radiotherapy seem to be essential. The role of chemotherapy remains unclear.

Ependymomas are rare central nervous system tumors. Half the patients experience recurrence and total resection is of major importance to obtain the most chance of cure. Thus, some patients undergo several repeated resections which may occasionally be at the origin of dissemination along the neuraxis and exceptionally to extraneural sites. We report the case of a boy who presented a multiple recurrence of his supratentorial ependymoma, first at initial site and then with cervical lymph nodes metastases, highlighting the fact that multiple surgical resections may confer an added risk for hematogeneous and lymphatic dissemination. The impact of adjuvant therapies on this risk is discussed.

Background Non-motor fluctuations represent a main source of disability in Parkinson's disease (PD). Among them, neuropsychiatric fluctuations are the most frequent and are often under-recognized by patients and physicians, partly because specific tools for assessment of neuropsychiatric fluctuations are lacking. Objective To develop a scale for detecting and evaluating the presence and the severity of neuropsychological symptoms during the ON and OFF phases of non-motor fluctuations. Methods Neuropsychiatric symptoms reported by PD patients in the OFF- and the ON-medication conditions were collected using different neuropsychiatric scales (BDI-II, BAI, Young, VAS, etc.). Subsequently, tree phases of a pilot study was performed for cognitive pretesting, identification of ambiguous or redundant items (item reduction), and to obtain preliminary data of acceptability of the new scale. In all the three phases, the scale was applied in both the OFF and ON condition during a levodopa challenge. Results Twenty items were selected for the final version of the neuropsychiatric fluctuation scale (NFS): ten items measured the ON neuropsychological symptoms and ten items the OFF neuropsychological manifestations. Each item rated from 0-3, providing respective subscores from 0 to 30. Conclusions Once validated, our NFS can be used to identify and quantify neuropsychiatric fluctuations during motor fluctuations. The main novelty is that it could be used in acute settings. As such, the NFS can assess the neuropsychiatric state of the patient at the time of examination. The next step will be to validate the NFS to be used in current practice.

Ewing's sarcoma (ES) is the second most common malignant bone tumor in children and young adults. ES may also occur as a primary soft tissue neoplasm without involvement of the bone and is then referred to as extraosseous ES (EES). The paediatric central nervous system extraosseous Ewing's sarcoma (CNS-EES) is an extremely rare entity since less than 20 cases have been reported in literature. Moreover, only less than 10 cases correspond to brain parenchyma primary tumors. These cases have been often misdiagnosed with other varieties of primary brain tumors, particularly those which were called PNET (Primitive Neuro-Ectodermal Tumor). We present a case of true intraparenchymal CNS-EES and a comparison of epidemiology, behaviour, treatment, and prognosis of CNS-EES and intracranial PNET cases.

Congenital disorders of glycosylation (CDG) constitute an ever-growing group of genetic diseases affecting the glycosylation of proteins. CDG individuals usually present with severe multisystem disorders. MAN1B1-CDG is a CDG with nonspecific clinical symptoms such as intellectual deficiency and developmental delay. Although up to 40 affected individuals were described so far, its final diagnosis is not straightforward using common biochemical methods due to the trace-level accumulation of defective glycan structures. In this study, we present three unreported MAN1B1-CDG individuals and propose a decision tree to reach diagnosis using a panel of techniques ranging from exome sequencing to gel electrophoresis and mass spectrometry. The occurrence of MAN1B1-CDG in patients showing unexplained intellectual disability and development delay, as well as a particular transferrin glycosylation profile, can be ascertained notably using matrix assisted laser desorption/ionization – time of flight (MALDI-TOF) mass spectrometry analysis of endo-β-acetylglucosaminidase H-released serum N-glycans. In addition to reporting new pathogenic variants and additional clinical signs such as hypersialorrhea, we highlight particular biochemical features of MAN1B1-CDG with potential glycoprotein-specific glycosylation defects.

Designed enzymes are of fundamental and technological interest. Experimental directed evolution still has significant limitations, and computational approaches are complementary. A designed enzyme should satisfy multiple criteria: stability, substrate binding, transition state binding. Such multi-objective design is computationally challenging. Two recent studies used adaptive importance sampling Monte Carlo to redesign proteins for ligand binding. By first flattening the energy landscape of the apo protein, they obtained positive design for the bound state and negative design for the unbound. We extend the method to the design of an enzyme for specific transition state binding, i.e., for catalytic power. We consider methionyl-tRNA synthetase (MetRS), which attaches methionine (Met) to its cognate tRNA, establishing codon identity. MetRS and other synthetases have been extensively redesigned by experimental directed evolution to accept noncanonical amino acids as substrates, leading to genetic code expansion. We redesigned MetRS computationally to bind several ligands: the Met analog azidonorleucine, methionyl-adenylate (MetAMP), and the activated ligands that form the transition state for MetAMP production. Enzyme mutants known to have azidonorleucine activity were recovered, and mutants predicted to bind MetAMP were characterized experimentally and found to be active. Mutants predicted to have low activation free energies for MetAMP production were found to be active and the predicted reaction rates agreed well with the experimental values. We expect the present method will become the paradigm for computational enzyme design.

Analogous to the B- and Z-DNA structures in double-helix DNA, there exist both right- and left-handed quadruple-helix (G-quadruplex) DNA. Numerous conformations of right-handed and a few left-handed G-quadruplexes were previously observed, yet they were always identified separately. Here, we present the NMR solution and X-ray crystal structures of a right- and left-handed hybrid G-quadruplex. The structure reveals a stacking interaction between two G-quadruplex blocks with different helical orientations and displays features of both right- and left-handed G-quadruplexes. An analysis of loop mutations suggests that single-nucleotide loops are preferred or even required for the left-handed G-quadruplex formation. The discovery of a right- and left-handed hybrid G-quadruplex further expands the polymorphism of G-quadruplexes and is potentially useful in designing a left-to-right junction in G-quadruplex engineering. NRF (Natl Research Foundation, S’pore) MOE (Min. of Education, S’pore) Published version

International audience; Understanding molecular mechanisms of ribosomal translation sheds light on the emergence and evolution of protein synthesis in the three domains of life. Universally, ribosomal translation is described in three steps: initiation, elongation and termination. During initiation, a macromolecular complex assembled around the small ribosomal subunit selects the start codon on the mRNA and defines the open reading frame. In this review, we focus on the comparison of start codon selection mechanisms in eukaryotes and archaea. Eukaryotic translation initiation is a very complicated process, involving many initiation factors. The most widespread mechanism for the discovery of the start codon is the scanning of the mRNA by a pre-initiation complex until the first AUG codon in a correct context is found. In archaea, long-range scanning does not occur because of the presence of Shine-Dalgarno (SD) sequences or of short 5' untranslated regions. However, archaeal and eukaryotic translation initiations have three initiation factors in common: e/aIF1, e/aIF1A and e/aIF2 are directly involved in the selection of the start codon. Therefore, the idea that these archaeal and eukaryotic factors fulfill similar functions within a common structural ribosomal core complex has emerged. A divergence between eukaryotic and archaeal factors allowed for the adaptation to the long-range scanning process versus the SD mediated prepositioning of the ribosome.

Only a few years after the introduction of levodopa, the first descriptions of motor fluctuations and dyskinesia related to dopaminergic therapy appeared. In PD, attention turned to their management, that had dampened the euphoria of the "levodopa miracle." It soon became clear that neuropsychiatric, autonomic, and sensory features also tend to develop fluctuations after chronic exposure to l-dopa. The diversity of fluctuating nonmotor symptoms, their largely subjective nature, coupled with a frequent lack of insight led to difficulties in identification and quantification. This may explain why, despite the high impact of nonmotor symptoms on patient autonomy and quality of life, evaluation of nonmotor fluctuations is not part of clinical routine. In view of the lack of specific validated assessment tools, detailed anamnesis should ideally be coupled with an evaluation in both ON and OFF drug conditions. The mechanisms of nonmotor fluctuations are not well understood. It is thought that they share dopaminergic presynaptic pharmacokinetic and postsynaptic pharmacodynamic mechanisms with the classical motor complications, but involve different neural pathways. Although symptoms fluctuate with dopaminergic treatment, serotonine and norepinephrine denervation, as well as interactions between neurotransmitter systems, probably contribute to their diversity. The lack of validated tools for assessment of these phenomena explains the almost complete absence of treatment studies. Management, largely resulting from expert opinion, includes psychiatric follow-up, nondopaminergic drugs, and advanced dopaminergic treatment, including drug delivery pumps and DBS. This review aims to provide a starting point for the understanding, diagnosis, and management of nonmotor fluctuations. © 2016 International Parkinson and Movement Disorder Society.

International audience; We report the evaluation of an automated method for quantification of brain tissue damage, caused by a severe traumatic brain injury, using mean diffusivity computed from MR diffusion images. Our automatic results obtained on realistic phantoms and real patient images 10 days post-event provided by nine different centers were coherent with four expert manually identified lesions. For realistic phantoms automated method scores were equal to 0.77, 0.77 and 0.83 for Dice, Precision and Sensibility respectively compared to 0.78, 0.72 and 0.86 for the experts. The inter correlation class (ICC) was 0.79. For 7/9 real cases 0.57, 0.50 and 0.70 were respectively obtained for automated method compared to 0.60, 0.52 and 0.78 for experts with ICC=0.71. Additionally, we detail the quality control module used to pool data from various image provider centers. This study clearly demonstrates the validity of the proposed automated method to eventually compute in a multi-centre project, the lesional load following brain trauma based on MD changes.

International audience; The Arp2/3 complex generates branched actin networks that exert pushing forces onto different cellular membranes. WASH complexes activate Arp2/3 complexes at the surface of endosomes and thereby fission transport intermediates containing endocy-tosed receptors, such as a5b1 integrins. How WASH complexes are assembled in the cell is unknown. Here, we identify the small coiled-coil protein HSBP1 as a factor that specifically promotes the assembly of a ternary complex composed of CCDC53, WASH, and FAM21 by dissociating the CCDC53 homotrimeric precursor. HSBP1 operates at the centrosome, which concentrates the building blocks. HSBP1 depletion in human cancer cell lines and in Dictyos-telium amoebae phenocopies WASH depletion, suggesting a critical role of the ternary WASH complex for WASH functions. HSBP1 is required for the development of focal adhesions and of cell polarity. These defects impair the migration and invasion of tumor cells. Overexpression of HSBP1 in breast tumors is associated with increased levels of WASH complexes and with poor prognosis for patients.

International audience; Eukaryotic and archaeal translation initiation processes involve a heterotrimeric GTPase e/aIF2 crucial for accuracy of start codon selection. In eu-karyotes, the GTPase activity of eIF2 is assisted by a GTPase-activating protein (GAP), eIF5. In ar-chaea, orthologs of eIF5 are not found and aIF2 GT-Pase activity is thought to be non-assisted. However , no in vitro GTPase activity of the archaeal factor has been reported to date. Here, we show that aIF2 significantly hydrolyses GTP in vitro. Within aIF2␥, H97, corresponding to the catalytic histidine found in other translational GTPases, and D19, from the GKT loop, both participate in this activity. Several high-resolution crystal structures were determined to get insight into GTP hydrolysis by aIF2␥. In particular, a crystal structure of the H97A mutant was obtained in the presence of non-hydrolyzed GTP. This structure reveals the presence of a second magnesium ion bound to GTP and D19. Quantum chemical/molecular mechanical simulations support the idea that the second magnesium ion may assist GTP hydrolysis by helping to neutralize the developing negative charge in the transition state. These results are discussed in light of the absence of an identified GAP in archaea to assist GTP hydrolysis on aIF2.