Intervertebral disc characterization by shear wave elastography: an in-vitro preliminary study

Patient-specific numerical simulation of the spine is a useful tool both in clinic and research. While geometrical personalization of the spine is no more an issue, thanks to recent technological advances, non-invasive personalization of soft tissue’s mechanical properties remains a challenge. Ultrasound elastography is a relatively recent measurement technique allowing the evaluation of soft tissue’s elastic modulus through the measurement of shear wave speed (SWS). The aim of this study was to determine the feasibility of elastographic measurements in intervertebral disc (IVD). An in-vitro approach was chosen to test the hypothesis that SWS can be used to evaluate IVD mechanical properties and to assess measurement repeatability. Eleven oxtail IVDs were tested in compression to determine their stiffness and apparent elastic modulus at rest and at 400 N. Elastographic measurements were performed in these two conditions and compared to these mechanical parameters. The protocol was repeated six times to determine elastographic measurement repeatability. Average SWS over all samples was 5.3 ± 1.0 m/s, with a repeatability of 7 % at rest and 4.6 % at 400 N; stiffness and apparent elastic modulus were 266.3 ± 70.5 N/mm and 5.4 ± 1.1 MPa at rest, respectively, while at 400 N they were 781.0 ± 153.8 N/mm and 13.2 ± 2.4 MPa. Correlations were found between elastographic measurements and IVD mechanical properties; these preliminary results are promising for further in-vivo application.The authors are grateful to the ParisTech BiomecAM chair program on subject-specific musculoskeletal modelling for funding (with the support of Proteor, ParisTech and Yves Cotrel Foundations)

Human pregnancy complicated by Chlamydia psittaci acquired from goat, a new zaonotic infection ?

Nous rapportons le cas d’une femme dont la grossesse s’est spontané ment interrompue à 32 semaines d’aménorrhée en raison d’une infection très sévère par Chlamydia psittaci. Cette infection est secondaire à un contact avec un troupeau de chèvres. Neuf cas d’infection materno-fœtale par Chlamydia psittaci d’origine animale sont décrits dans la littérature, il s’agit toujours d’une contamination par les brebis atteintes de chlamydiose abortive. La chèvre peut également être infectée par ce germe, mais la trans mission à la femme enceinte de la chlamydiose abortive caprine n’a pas été décrit jusqu’à présent.A case of chlamydial infection in pregnant woman is described. This infection was contracted from goat. The woman, who had contact with caprine abortion, spontaneously delivered a stillborn infant in the 32nd week of pregnancy. She developed dessiminated intravascular coagulation post partum with acute renal failure and pulmonary oedema. Nine cases of chlamydial infections in pregnant women have been reported in literature, in all cases, the infection was contracted from ewes suffering from enzootic abortion. Such an infection acquired from goat have not been previously described

Inter-annotator agreement for a speech corpus pronounced by French and German language learners

International audienceThis paper presents the results of an investigation of inter-annotator agreement for the non-native and native French part of the IFCASL corpus. This large bilingual speech corpus for French and German language learners was manually annotated by several annotators. This manual annotation is the starting point which will be used both to improve the automatic segmentation algorithms and derive diagnosis and feedback. The agreement is evaluated by comparing the manual alignments of seven annotators to the manual alignment of an expert, for 18 sentences. Whereas results for the presence of the devoicing diacritic show a certain degree of disagreement between the annotators and the expert, there is a very good consistency between annotators and the expert for temporal boundaries as well as insertions and deletions. We find a good overall agreement for boundaries between annotators and expert with a mean deviation of 7.6 ms and 93% of boundaries within 20 ms

A locus-specific database for mutations in GDAP1 allows analysis of genotype-phenotype correlations in Charcot-Marie-Tooth diseases type 4A and 2K

<p>Abstract</p> <p>Background</p> <p>The ganglioside-induced differentiation-associated protein 1 gene (<it>GDAP1</it>), which is involved in the Charcot-Marie-Tooth disease (CMT), the most commonly inherited peripheral neuropathy, encodes a protein anchored to the mitochondrial outer membrane. The phenotypic presentations of patients carrying <it>GDAP1 </it>mutations are heterogeneous, making it difficult to determine genotype-phenotype correlations, since the majority of the mutations have been found in only a few unrelated patients. Locus-specific databases (LSDB) established in the framework of the Human Variome Project provide powerful tools for the investigation of such rare diseases.</p> <p>Methods and Results</p> <p>We report the development of a publicly accessible LSDB for the <it>GDAP1 </it>gene. The <it>GDAP1</it> LSDB has adopted the Leiden Open-source Variation Database (LOVD) software platform. This database, which now contains 57 unique variants reported in 179 cases of CMT, offers a detailed description of the molecular, clinical and electrophysiological data of the patients. The usefulness of the <it>GDAP1 </it>database is illustrated by the finding that <it>GDAP1 </it>mutations lead to primary axonal damage in CMT, with secondary demyelination in the more severe cases of the disease.</p> <p>Conclusion</p> <p>Findings of this nature should lead to a better understanding of the pathophysiology of CMT. Finally, the <it>GDAP1 </it>LSDB, which is part of the mitodyn.org portal of databases of genes incriminated in disorders involving mitochondrial dynamics and bioenergetics, should yield new insights into mitochondrial diseases.</p

Détection automatique de sons bien réalisés

Colloque avec actes et comité de lecture. nationale.National audienceGiven a phonetic context, sounds can be uttered with more or less salient acoustic cues depending on the speech style and prosody. In a previous work we studied strong acoustic cues of unvoiced stops that enable a very reliable identification of stops. In this paper we use this background idea again with a view of exploiting well realized sounds to enhance speech intelligibility within the framework of language learning. We thus designed an elitist learning of HMM that make very reliable phone models emerge. The learning is iterated by feeding phones identified correctly at the previous iteration into the learning algorithm. In this way models specialize to represent well realized sounds. Experiments were carried out on the BREF 80 corpus by constructing well realized phone models for unvoiced stops. They show that these contextual models triggered off in 60% of stops occurrences with an extremely low confusion rate

Simultaneous MFN2 and GDAP1 mutations cause major mitochondrial defects in a patient with CMT

Mutations in the MFN2 gene are associated with Charcot-Marie-Tooth disease type 2A (CMT2A), a dominant axonal CMT, whereas mutations in GDAP1 are associated with recessive demyelinating CMT (CMT4A), recessive axonal CMT (AR-CMT2), and dominant axonal CMT (CMT2K). Both proteins are involved in energy metabolism and dynamics of the mitochondrial network. We have previously reported that, in fibroblasts from patients with CMT, MFN2 mutations resulted in a mitochondrial energy coupling defect, whereas dominant mutation in GDAP1 resulted in defective complex I activity. In this study, we investigated mitochondrial bioenergetics from a severely affected patient with CMT harboring combined mutations in both GDAP1 and MFN2 genes

Acute and late-onset optic atrophy due to a novel OPA1 mutation leading to a mitochondrial coupling defect

PurposeAutosomal dominant optic atrophy (ADOA, OMIM 165500), an inherited optic neuropathy that leads to retinal ganglion cell degeneration and reduced visual acuity during the early decades of life, is mainly associated with mutations in the OPA1 gene. Here we report a novel ADOA phenotype associated with a new pathogenic OPA1 gene mutation. Methods The patient, a 62-year-old woman, was referred for acute, painless, and severe visual loss in her right eye. Acute visual loss in her left eye occurred a year after initial presentation. MRI confirmed the diagnosis of isolated atrophic bilateral optic neuropathy. We performed DNA sequencing of the entire coding sequence and the exon/intron junctions of the OPA1 gene, and we searched for the mitochondrial DNA mutations responsible for Leber hereditary optic atrophy by sequencing entirely mitochondrial DNA. Mitochondrial respiratory chain complex activity and mitochondrial morphology were investigated in skin fibroblasts from the patient and controls. Results We identified a novel heterozygous missense mutation (c.2794C&gt;T) in exon 27 of the OPA1 gene, resulting in an amino acid change (p.R932C) in the protein. This mutation, which affects a highly conserved amino acids, has not been previously reported, and was absent in 400 control chromosomes. Mitochondrial DNA sequence analysis did not reveal any mutation associated with Leber hereditary optic neuropathy or any pathogenic mutations. The investigation of skin fibroblasts from the patient revealed a coupling defect of oxidative phosphorylation and a larger proportion of short mitochondria than in controls. Conclusions The presence of an OPA1 mutation indicates that this sporadic, late-onset acute case of optic neuropathy is related to ADOA and to a mitochondrial energetic defect. This suggests that the mutational screening of the OPA1 gene would be justified in atypical cases of optic nerve atrophy with no evident cause

An elitist approach for extracting automatically well-realized speech sounds with high confidence

This paper presents an ëlitist approach\" for extracting automatically well-realized speech sounds with high confidence. The elitist approach uses a speech recognition system based on Hidden Markov Models (HMM). The HMM are trained on speech sounds which are systematically well-detected in an iterative procedure. The results show that, by using the HMM models defined in the training phase, the speech recognizer detects reliably specific speech sounds with a small rate of errors

Cervical Muscle Volume Study

Purpose To quantify the cervical muscle volume variation by means of three‐dimensional reconstruction from MRI images. Materials and Methods Sixteen subjects were scanned using a Philips MRI scanner, including 11 men and 5 women, aged from 23 to 33 years, weighting between 49–80 kg. The deformation of a parametric specific object method was used to develop three‐dimensional muscle models from contours on a small number of MRI images. Six subjects were reconstructed by two observers for evaluating the reliability by means of intraclass correlation coefficient (ICC). The results were also compared with in vivo measurement on a single specimen from a reference literature. The difference in left and right muscles volumes was assessed with a paired Wilcoxon signed rank test. Results The results showed good reliability by means of ICC study and were consistent with the in vivo specimen measurements. The left and right paired muscle volumes showed no significant difference. Interindividual variance was large that could reach 364 cm3, but the ratio of a given muscle volume to the total volume was less variable, always lower than 13%. The maximum cross sectional areas of cervical muscles varied greatly between individuals and the maximum values were mostly found at the C6–C7 level. Conclusion This study provides initial results which could be used as reference data for clinical evaluation and biomechanical model development