Homochiral oligopeptides by chiral amplification: Interpretation of experimental data with a copolymerization model

We present a differential rate equation model of chiral polymerization based on a simple copolymerization scheme in which the enantiomers are added to, or removed from, the homochiral or heterochiral chains (reversible stepwise isodesmic growth or dissociation). The model is set up for closed systems and takes into account the corresponding thermodynamic constraints implied by the reversible monomer attachments, while obeying a constant mass constraint. In its simplest form, the model depends on a single variable rate constant, the maximum chain length N, and the initial concentrations. We have fit the model to the experimental data from the Rehovot group on lattice-controlled chiral amplification of oligopeptides. We find in all the chemical systems employed except for one, that the model fits the measured relative abundances of the oligopetides with higher degrees of correlation than from a purely random polymerization process.Comment: 18 pages, 12 figures, 9 table

Cervical laminectomy and micro resection of the posterior venous plexus in Hirayama disease.

Introduction. Hirayama disease is a rare cervical myelopathy predominantly affecting young adults andmainly found in Asia. It results in a pure motor distal lesion of the upper limbs with slow progression.Dynamic magnetic resonance imaging (MRI), which allows the diagnosis to be made, shows a typical appearance of anterior compression of the cervical spinal cord associated with enlargement of the poste-rior epidural spaces due to a dilated venous plexus. Surgery is considered when conservative treatmenthas failed. However, the type of surgery is not well standardized in this compressive myelopathy.Methods. – We report on three patients with Hirayama disease operated using an original method: cer-vical decompressive laminectomy and coagulation of the posterior epidural plexus without fixation. The clinical, radiological and surgical data of these three patients were analyzed. Each patient underwent postoperative MR imaging.Results. – The mean age at diagnosis was 18.6 years (16–20 years) with a history of progressive symptomslasting 1 to 4 years before treatment. Follow-up was 21 to 66 months after surgery. Neurological and electrophysiological improvement was noted in two patients; the third had stabilized. Post operative MRI confirmed normalization of flexion imaging on MRI. None of the three patients complained of disablingneck pain.Conclusion. – Posterior cervical decompression with coagulation of epidural venous plexus is a technique that seems effective in Hirayama disease in young subjects. It effectively treats patients by avoiding permanent cervical fixation.The authors declare that they have no competing interest

Mutation update and genotype-phenotype correlations of novel and previously described mutations in TPM2 and TPM3 causing congenital myopathies

Mutations affecting skeletal muscle isoforms of the tropomyosin genes may cause nemaline myopathy, cap myopathy, core-rod myopathy, congenital fiber-type disproportion, distal arthrogryposes, and Escobar syndrome. We correlate the clinical picture of these diseases with novel (19) and previously reported (31) mutations of the TPM2 and TPM3 genes. Included are altogether 93 families: 53 with TPM2 mutations and 40 with TPM3 mutations. Thirty distinct pathogenic variants of TPM2 and 20 of TPM3 have been published or listed in the Leiden Open Variant Database (http://www.dmd.nl/). Most are heterozygous changes associated with autosomal-dominant disease. Patients with TPM2 mutations tended to present with milder symptoms than those with TPM3 mutations, DA being present only in the TPM2 group. Previous studies have shown that five of the mutations in TPM2 and one in TPM3 cause increased Ca2+ sensitivity resulting in a hypercontractile molecular phenotype. Patients with hypercontractile phenotype more often had contractures of the limb joints (18/19) and jaw (6/19) than those with nonhypercontractile ones (2/22 and 1/22), whereas patients with the non-hypercontractile molecular phenotype more often (19/22) had axial contractures than the hypercontractile group (7/19). Our in silico predictions show that most mutations affect tropomyosin–actin association or tropomyosin head-to-tail binding

Potentialisation de la fibrinolise par les ultrasons à la phase aiguë des accidents ischémiques cérébraux

TOULOUSE3-BU Santé-Centrale (315552105) / SudocTOULOUSE3-BU Santé-Allées (315552109) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

Hepatitis E Virus Infection: Neurological Manifestations and Pathophysiology

Hepatitis E virus (HEV) is the first cause of viral hepatitis in the world. While the water-borne HEV genotypes 1 and 2 are found in developing countries, HEV genotypes 3 and 4 are endemic in developed countries due to the existence of animal reservoirs, especially swine. An HEV infection produces many extra-hepatic manifestations in addition to liver symptoms, especially neurological disorders. The most common are neuralgic amyotrophy or Parsonage–Turner syndrome, Guillain–Barré syndrome, myelitis, and encephalitis. The pathophysiology of the neurological injuries due to HEV remains uncertain. The immune response to the virus probably plays a role, but direct virus neurotropism could also contribute to the pathophysiology. This review describes the main neurological manifestations and their possible pathogenic mechanisms

Hepatitis E Virus Infection: Neurological Manifestations and Pathophysiology

Hepatitis E virus (HEV) is the first cause of viral hepatitis in the world. While the water-borne HEV genotypes 1 and 2 are found in developing countries, HEV genotypes 3 and 4 are endemic in developed countries due to the existence of animal reservoirs, especially swine. An HEV infection produces many extra-hepatic manifestations in addition to liver symptoms, especially neurological disorders. The most common are neuralgic amyotrophy or Parsonage–Turner syndrome, Guillain–Barré syndrome, myelitis, and encephalitis. The pathophysiology of the neurological injuries due to HEV remains uncertain. The immune response to the virus probably plays a role, but direct virus neurotropism could also contribute to the pathophysiology. This review describes the main neurological manifestations and their possible pathogenic mechanisms

Motor unit number index as an individual biomarker: Reference limits of intra-individual variability over time in healthy subjects

peer reviewe

Le jeu sérieux au service de l’apprentissage des physiothérapeutes : retour d’expérience et étude pilote à propos du dispositif PETRHA

Contexte : La littérature accrédite le fait que les techniques d’information et de communication éducatives (TICE) deviennent incontournables. Les travaux de recherches consacrés à l’évaluation des jeux sérieux (serious game – SG) appliqués à la médecine et à la santé sont en constante évolution. Peu d’études ont évalué l’impact sur l’apprentissage de la mise en place d’un SG dans le domaine de la masso-kinésithérapie (MK) (ou physiothérapie). Objectifs : Cet article présente PETRHA (Physiotherapy E-training Re-Habilitation), le premier SG en physiothérapie. Il rend compte d’un retour d’expérience de son expérimentation pour l’enseignement et l’apprentissage du raisonnement clinique des étudiants en formation initiale de MK. Méthodes : Des méthodes d’analyse de contenu lexical et thématique de réponse d’étudiants à une enquête ont été mises en oeuvre. Résultats : Les résultats mettent en évidence plusieurs points positifs mais aussi certaines difficultés liées à une implantation purement logistique du dispositif PETHRA. Conclusion : Le travail rapporté a permis d’identifier un certain nombre de conditions didactiques et pédagogiques minimales à satisfaire lorsque l’on souhaite exploiter la ressource que constitue le SG PETRHA pour favoriser l’apprentissage du raisonnement clinique en formation initiale de kinésithérapie

A complex homozygous mutation in ABHD12 responsible for PHARC syndrome discovered with NGS and review of the literature

International audiencePHARC syndrome (MIM612674) is an autosomal recessive neurodegenerative pathology that leads to demyelinating Polyneuropathy, Hearing loss, cerebellar Ataxia, Retinitis pigmentosa, and early-onset Cataracts (PHARC). These various symptoms can appear at different ages. PHARC syndrome is caused by mutations in ABHD12 (α-β hydrolase domain 12), of which several have been described. We report here a new complex homozygous mutation c.379_385delAACTACTinsGATTCCTTATATACCATTGTAGTCTTACTGCTTTTGGTGAACACA (p.Asn127Aspfs*23). This mutation was detected in a 36-year-old man, who presented neuropathic symptoms from the age of 15, using a next-generation sequencing panel. This result suggests that the involvement of ABHD12 in polyneuropathies is possibly underestimated. We then performed a comparative study of other patients presenting ABHD12 mutations and searched for genotype-phenotype correlations and functional explanations in this heterogeneous population

Dry immersion as a model of deafferentation: A neurophysiology study using somatosensory evoked potentials.

INTRODUCTION:Dry immersion is a ground-based experiment simulating the effects of weightlessness, and it is a model of acute symmetrical bilateral deafferentation. This exploratory study aimed to investigate the effects of three days of dry immersion (DI) on sensory thresholds and the functioning of lemniscal pathways, assessed by somatosensory evoked potentials (SEPs). METHODS:Twelve healthy male volunteers (32+/-4.8 years) participated in the study. Sensory thresholds and SEPs of the tibial nerve of both limbs were recorded before (D-1) and on the third day of dry immersion (D3). RESULTS:Sensory thresholds significantly decreased on D3 (-20.75 +/-21.7%; z = -2.54; p = 0.0109 on the right side and -22.18+/-17.28%; z = -3.059; p = 0.002 on the left side). The amplitude of P40 responses did not differ between D-1 and D3. Latencies of all central responses until P30 were shortened on D3 (N21 right:-0.57+/-0.31; z = -3.06; p = 0.002; N21 left -0.83+/-0.53; z = -2.94; p = 0.003; P30 right: -1.26+/-1.42; z = -3.059; p = 0.002; P30 left: -1.11+/-1.55; z = -2.27; p = 0.02). CONCLUSION:Three days of dry immersion can induce hyperexcitability of lemniscal pathways. SIGNIFICANCE:This may be explained by a change in the expression of membrane channels and/or medullar plasticity and/or hypersensitization of peripheral sensory receptors induced by this acute deafferentation. Additional studies are needed to further elucidate the mechanisms