Beyond seek and destroy: How to generate allelic series using genome editing tools

Genome editing tools have greatly facilitated the functional analysis of genes of interest by targeted mutagenesis. Many usable genome editing tools, including different site-specific nucleases and editor databases that allow single-nucleotide polymorphisms (SNPs) to be introduced at a given site, are now available. These tools can be used to generate high allelic diversity at a given locus to facilitate gene function studies, including examining the role of a specific protein domain or a single amino acid. We compared the effects, efficiencies and mutation types generated by our LbCPF1, SpCAS9 and base editor (BECAS9) constructs for the OsCAO1 gene. SpCAS9 and LbCPF1 have similar efficiencies in generating mutations but differ in the types of mutations induced, with the majority of changes being single-nucleotide insertions and short deletions for SpCAS9 and LbCPF1, respectively. The proportions of heterozygotes also differed, representing a majority in our LbCPF1, while with SpCAS9, we obtained a large number of biallelic mutants. Finally, we demonstrated that it is possible to specifically introduce stop codons using the BECAS9 with an acceptable efficiency of approximately 20%. Based on these results, a rational choice among these three alternatives may be made depending on the type of mutation that one wishes to introduce, the three systems being complementary. SpCAS9 remains the best choice to generate KO mutations in primary transformants, while if the desired gene mutation interferes with regeneration or viability, the use of our LbCPF1 construction will be preferred, because it produces mainly heterozygotes. LbCPF1 has been described in other studies as being as effective as SpCAS9 in generating homozygous and biallelic mutations. It will remain to be clarified in the future, whether the different LbCFP1 constructions have different efficiencies and determine the origin of these differences. Finally, if one wishes to specifically introduce stop codons, BECAS9 is a viable and efficient alternative, although it has a lower efficiency than SpCAS9 and LbCPF1 for creating KO mutations

Localization, detection and measurement of an aortic aneurysm

La détection automatique d'un anévrisme aortique peut apporter au médecin une aide considérable pour le diagnostic médical d'autant plus lorsqu'une mesure automatisée et reproductible peut y être associée et réalisée. Nous avons ainsi développé une nouvelle méthode de localisation totalement automatique de l'aorte abdominale sur des images scanner. Une fois l'aorte localisée, un algorithme fondé sur une croissance de région 3D a permis la segmentation des contours de la partie circulante de l'aorte. Ensuite, une méthode originale évaluant l'existence d'un anévrisme a été mise en place dans le but de déterminer les contours et la mesure de cet anévrisme s'il existe

Modélisation des signaux et des images par les attracteurs fractals de systèmes de fonctions itérées (IFS)

Les systèmes de fonctions itérées (IFS) constituent des modèles fractals possédant des propriétés multiéchelles susceptibles de décrire de nombreux processus complexes. Un modèle d'IFS 1D minimal est utilisé pour en comprenbdre et en maîtriser les mécanismes. Notre étude a permis la modélisation de signaux avec un contrôle des moments géométriques, des coefficients de Fourier complexes ou réels, de la dimension fractale et de la continuité. Cette analyse systématique a ensuite été étendue à des modèles basiques d'IFS en 2 et 3 dimensions. Ces modèles ont également permis de décrire les modifications des propriétés de l'attracteur lorsqu'il est projeté. Toutes les propriétés démontrées dans cette étude améliorent la compréhension et les possibilités de contrôle de ces modèles d'IFS. Bien que s'agissant de modèles minimaux, ces modèles fractals montrent d'énormes potentialités d'applications dans des domaines très variés en signal image.résumé en anglaisANGERS-BU Lettres et Sciences (490072106) / SudocSudocFranceF

Oculomotor muscles segmentation in cerebral-orbital MRI for exophthalmy diagnosis aid

Problème traité - Segmentation des muscles oculomoteurs en IRM cérébro-orbitaire pour l'aide au diagnostic et au suivi thérapeutique de l'exophtalmie. Originalité - Mise en place d'une méthode de segmentation semi-automatique se fondant sur l'utilisation de contours actifs de type « courbes de niveaux hybrides ». Résultats - Méthode de segmentation rapide et précise qui se présente comme une alternative intéressante pour l'analyse d'un grand nombre d'images dans le cadre d'une étude clinique d'envergure

Follow-up of coiled intracranial aneurysms: comparison of 3D time-of-flight and contrast-enhanced magnetic resonance angiography at 3T in a large, prospective series.

International audienceOBJECTIVES: To compare 3D-TOF magnetic resonance angiography (MRA) and contrast-enhanced MRA (CE-MRA) sequences at 3T in the follow-up of coiled aneurysms with digital subtracted angiography (DSA) as the gold standard. METHODS: DSA, 3D-TOF and CE-MRA were performed in a prospective series of 126 aneurysms in 96 patients (57 female, 39 male; age: 25-75 years, mean: 51.3 ± 11.3 years). The quality of aneurysm occlusion was assessed independently and anonymously by a core laboratory. RESULTS: Using DSA (gold standard technique), total occlusion was depicted in 57 aneurysms (45.2%), neck remnant in 34 aneurysms (27.0%) and aneurysm remnant in 35 aneurysms (27.8%). Sensitivity, specificity, positive predictive value and negative predictive value were very similar with 3D-TOF and CE-MRA. Visibility of coils was much better with 3D-TOF (95.2%) than with CE-MRA (23.0%) (P < 0.001). Also, substantial artefacts were less frequent with 3D-TOF (4.0%) than with CE-MRA (11.9%; P = 0.012). CONCLUSIONS: In this large prospective series of patients with coiled aneurysms, at 3T 3D-TOF MRA was equivalent to CE-MRA for the evaluation of aneurysm occlusion, but coil visibility was superior at 3D-TOF. Thus the use of 3D-TOF at 3T is recommended for the follow-up of coiled intracranial aneurysms. KEY POINTS: * Different Magnetic Resonance (MR) imaging techniques are used to evaluate intracranial aneurysms. * At 3T MR, 3D-TOF and CE-MRA appear equivalent for evaluating coiled aneurysms.. * Coils are better visualised on 3D-TOF than on CE-MRA. * Combined analysis of 3D-TOF and CE-MRA does not seem helpful. * At 3T, 3D-TOF techniques are recommended for monitoring patients with coiled aneurysms

Follow-up of intracranial aneurysms treated with stent-assisted coiling: Comparison of contrast-enhanced MRA, time-of-flight MRA, and digital subtraction angiography

International audienceBackground and purposeData about non-invasive follow-up of aneurysm after stent-assisted coiling is scarce. We aimed to compare time-of-flight (TOF) magnetic resonance angiography (MRA) (3D-TOF-MRA) and contrast-enhanced MRA (CE-MRA) at 3-Tesla, with digital subtraction angiography (DSA) for evaluating aneurysm occlusion and parent artery patency after stent-assisted coiling.Materials and methodsIn this retrospective single-center study, patients were included if they had an intracranial aneurysm treated by stent-assisted coiling between March 2008 and June 2015, followed with both MRA sequences (3D-TOF-MRA and CE-MRA) at 3-Tesla and DSA, performed in an interval < 48 hours.ResultsThirty-five aneurysms were included. Regarding aneurysm occlusion evaluation, agreement with DSA was better for CE-MRA (K = 0.53) than 3D-TOF-MRA (K = 0.28). Diagnostic accuracies for aneurysm remnant depiction were similar for 3D-TOF-MRA and CE-MRA (P = 1). Both 3D-TOF-MRA (K = 0.05) and CE-MRA (K = −0.04) were unable to detect pathological vessel compared to DSA, without difference in accuracy (P = 0.68). For parent artery occlusion detection, agreement with DSA was substantial for 3D-TOF-MRA (K = 0.64) and moderate for CE-MRA (K = 0.45), with similar good diagnostic accuracies (P = 1).ConclusionAfter stent-assisted coiling treatment, 3D-TOF-MRA and CE-MRA demonstrated good accuracy to detect aneurysm remnant (but tended to overestimation). Although CE-MRA agreement with DSA was better, there was no statistical difference between 3D-TOF-MRA and CE-MRA accuracies. Both MRAs were unable to provide a precise evaluation of in-stent status but could detect parent vessel occlusion

Follow-up of intracranial aneurysms treated by flow diverter: comparison of three-dimensional time-of-flight MR angiography (3D-TOF-MRA) and contrast-enhanced MR angiography (CE-MRA) sequences with digital subtraction angiography as the gold standard

International audienceBackground and purpose: Follow-up of intracranial aneurysms treated by flow diverter with MRI is complicated by imaging artifacts produced by these devices. This study compares the diagnostic accuracy of three-dimensional time-of-flight MR angiography (3D-TOF-MRA) and contrast-enhanced MRA (CE-MRA) at 3 T for the evaluation of aneurysm occlusion and parent artery patency after flow diversion treatment, with digital subtraction angiography (DSA) as the gold standard.Materials and methods: Patients treated with flow diverters between January 2009 and January 2013 followed by MRA at 3 T (3D-TOF-MRA and CE-MRA) and DSA within a 48 h period were included in a prospective single-center study. Aneurysm occlusion was assessed with full and simplified Montreal scales and parent artery patency with three-grade and two-grade scales.Results: Twenty-two patients harboring 23 treated aneurysms were included. Interobserver agreement using simplified scales for occlusion (Montreal) and parent artery patency were higher for DSA (0.88 and 0.61) and CE-MRA (0.74 and 0.55) than for 3D-TOF-MRA (0.51 and 0.02). Intermodality agreement was higher for CE-MRA (0.88 and 0.32) than for 3D-TOF-MRA (0.59 and 0.11). CE-MRA yielded better accuracy than 3D-TOF-MRA for aneurysm remnant detection (sensitivity 83% vs 50%; specificity 100% vs 100%) and for the status of the parent artery (specificity 63% vs 32%; sensitivity 100% vs 100%).Conclusions: At 3 T, CE-MRA is superior to 3D-TOF-MRA for the evaluation of aneurysm occlusion and parent artery patency after flow diversion treatment. However, intraluminal evaluation remains difficult with MRA regardless of the sequence used

Role of MRA in the detection of intracranial aneurysm in the acute phase of subarachnoid hemorrhage

International audienceBackground: Magnetic resonance angiography (MRA) has been evaluated for the detection of unruptured intracranial aneurysms with favorable results at 3 Tesla (3 T) and with similar diagnostic accuracy as both 3D time-of-flight (3D-TOF) and contrast-enhanced (CE-MRA) MRA. However, the diagnostic value and place of MRA in the detection of ruptured aneurysms has been little evaluated. Thus, the goal of this prospective single-center series was to assess the feasibility and diagnostic value of 3 T 3D-TOF MRA and CE-MRA for aneurysm detection in acute non-traumatic subarachnoid hemorrhage (SAH).Methods: From March 2006 to December 2007, all consecutive patients admitted to our hospital with acute non-traumatic SAH (≤ 10 days) were prospectively included in this study evaluating MRA in the diagnostic workup of SAH. Feasibility of MRA and sensitivity/specificity of 3D-TOF and CE-MRA were assessed compared with gold standard DSA.Results: In all, 84 consecutive patients (45 women, 39 men; age 23–86 years) were included. The feasibility of MRA was low (43/84, 51.2%). The reasons given for patients not undergoing magnetic resonance imaging (MRI) examination were clinical status (27 patients), potential delay in aneurysm treatment (11 patients) and contraindications to MRI (three patients). In patients explored by MRA, the sensitivity of CE-MRA (95%) was higher compared with 3D-TOF (86%) with similar specificity (80%). Also, 3D-TOF missed five aneurysms while CE-MRA missed two.Conclusion: The value of MRA in the diagnostic workup of ruptured aneurysms is limited due to its low feasibility during the acute phase of bleeding. Sensitivity for aneurysm detection was good for both MRA techniques, but tended to be better with CE-MRA

Role of MRA in the detection of intracranial aneurysm in the acute phase of subarachnoid hemorrhage

International audienceBackground: Magnetic resonance angiography (MRA) has been evaluated for the detection of unruptured intracranial aneurysms with favorable results at 3 Tesla (3 T) and with similar diagnostic accuracy as both 3D time-of-flight (3D-TOF) and contrast-enhanced (CE-MRA) MRA. However, the diagnostic value and place of MRA in the detection of ruptured aneurysms has been little evaluated. Thus, the goal of this prospective single-center series was to assess the feasibility and diagnostic value of 3 T 3D-TOF MRA and CE-MRA for aneurysm detection in acute non-traumatic subarachnoid hemorrhage (SAH).Methods: From March 2006 to December 2007, all consecutive patients admitted to our hospital with acute non-traumatic SAH (≤ 10 days) were prospectively included in this study evaluating MRA in the diagnostic workup of SAH. Feasibility of MRA and sensitivity/specificity of 3D-TOF and CE-MRA were assessed compared with gold standard DSA.Results: In all, 84 consecutive patients (45 women, 39 men; age 23–86 years) were included. The feasibility of MRA was low (43/84, 51.2%). The reasons given for patients not undergoing magnetic resonance imaging (MRI) examination were clinical status (27 patients), potential delay in aneurysm treatment (11 patients) and contraindications to MRI (three patients). In patients explored by MRA, the sensitivity of CE-MRA (95%) was higher compared with 3D-TOF (86%) with similar specificity (80%). Also, 3D-TOF missed five aneurysms while CE-MRA missed two.Conclusion: The value of MRA in the diagnostic workup of ruptured aneurysms is limited due to its low feasibility during the acute phase of bleeding. Sensitivity for aneurysm detection was good for both MRA techniques, but tended to be better with CE-MRA

Differential bilateral involvement of the parietal gyrus during predicative metaphor processing: An auditory fMRI study

International audienceDespite the growing literature on figurative language processing, there is still debate as to which cognitive processes and neural bases are involved. Furthermore, most studies have focused on nominal metaphor processing without any context, and very few have used auditory presentation. We therefore investigated the neural bases of the comprehension of predicative metaphors presented in a brief context, in an auditory, ecological way. The comprehension of their literal counterparts served as a control condition. We also investigated the link between working memory and verbal skills and regional activation. Comparisons of metaphorical and literal conditions revealed bilateral activation of parietal areas including the left angular (lAG) and right inferior parietal gyri (rIPG) and right precuneus. Only verbal skills were associated with lAG (but not rIPG) activation. These results indicated that predicative metaphor comprehension share common activations with other metaphors. Furthermore, individual verbal skills could have an impact on figurative language processing