Regeneration of myelin sheaths of normal length and thickness in the zebrafish CNS correlates with growth of axons in caliber

Demyelination is observed in numerous diseases of the central nervous system, including multiple sclerosis (MS). However, the endogenous regenerative process of remyelination can replace myelin lost in disease, and in various animal models. Unfortunately, the process of remyelination often fails, particularly with ageing. Even when remyelination occurs, it is characterised by the regeneration of myelin sheaths that are abnormally thin and short. This imperfect remyelination is likely to have implications for the restoration of normal circuit function and possibly the optimal metabolic support of axons. Here we describe a larval zebrafish model of demyelination and remyelination. We employ a drug-inducible cell ablation system with which we can consistently ablate 2/3rds of oligodendrocytes in the larval zebrafish spinal cord. This leads to a concomitant demyelination of 2/3rds of axons in the spinal cord, and an innate immune response over the same time period. We find restoration of the normal number of oligodendrocytes and robust remyelination approximately two weeks after induction of cell ablation, whereby myelinated axon number is restored to control levels. Remarkably, we find that myelin sheaths of normal length and thickness are regenerated during this time. Interestingly, we find that axons grow significantly in caliber during this period of remyelination. This suggests the possibility that the active growth of axons may stimulate the regeneration of myelin sheaths of normal dimensions

Hémoglobine glyquée : le temps de la standardisation est venu

Le dosage de l'hémoglobine glyquée est utilisé en pratique quotidienne pour le suivi à long terme de l'équilibre glycémique chez les patients atteints de diabète sucré. De nombreuses techniques ont été décrites depuis une vingtaine d'années, fondées sur différents principes, et dosant différentes formes glyquées de l'hémoglobine. Cela explique que, bien que ce test très informatif soit utilisé au quotidien par les diabétologues, il existe encore une grande disparité des résultats d'un laboratoire à l'autre, rendant leur comparaison impossible

Guide aux eaux de Bourbon l'Archambault, descriptif et médical, par le Dr. C. Périer,...

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Notice sur les eaux minérales de Bourbon-l'Archambault (Allier), composition chimique et applications thérapeutiques, par G. Périer,...

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REFLEXIONS SUR LES PROGRAMMES DE READAPTATION DES PATIENTS PORTEURS D'IMPLANTS COCHLEAIRES, EN FONCTION DE L'EXPERIENCE ACQUISE EN LOGOPEDIE D'ENFANTS SOURDS

Rehabilitation of patients after cochlear implant surgery should be planified along the same basic principles as those that have been envolved for the adaptation of patients to a classical hearing aid or acoustic prosthesis. When this is adapted to a patient with a sensorineural hearing loss, the quality of hearing differs from that of normal hearing because the pathological inner ear introduces distorsions. The patient therefore has to be trained to equate the new auditory sensations with those he had previously, which is basically the same situation as with a cochlea implant. some profoundly or totally deaf patients are fitted with vibro-tactile aids and they also have to be trained to make use of these new sensations in a meaningful way for an aid to speech understanding. For the above reasons the term 'cochlear prosthesis' is considered particularly adequate. It also has the advantage of playing down the surgical aspect of this new technique, often overemphasized by the media and creating exaggerated emotional involvement of the patients. If the above facts are recognized, one should entrust the rehabilitation of patients fitted with cochlear prostheses to logopeds (speechtherapists) well trained in the habilitation and prosthetic adaptation of profoundly deaf children. Only they have the expertise necessary to devise and apply a program founded upon experience. This will help avoid the pitfalls into which several surgically directed cochlear implant teams are currently falling. One of these is to design a training program in function of the tests meant to measure the patients' new capacities. Modern logopedics for deaf children stress motivation, linguistic and relational context and suprasegmental aspects of spoken language in contrast with the more analytical approaches utilized twenty years ago. The latter are the basis of the tests devised to quantify the benefits brought to the cochlear implant patients. Their validity as tools of measurement is not questioned, but to make them the basis of the rehabilitation process carries the risk of demotivation, at least where the congenitally deaf are concerned, and of failing to maximalize the potential benefits of this promising new technique.SCOPUS: NotDefined.jinfo:eu-repo/semantics/publishe

Dosage de l'hémoglobine A1C et hémoglobinopathies : problèmes posés et conduite à tenir

La valeur sémiologique de l'hémoglobine A1c (HbA1c) en tant que marqueur rétrospectif cumulatif de l'équilibre glycémique chez le patient diabétique est prise en défaut en cas d'hémoglobinopathie. La présence d'une hémoglobine anormale engendre des problèmes méthodologiques en raison des interférences provoquées dans la plupart des dosages, mais surtout perturbe le processus normal de glycation de l'HbA en HbA1c, et provoque souvent un certain degré d'hémolyse, très variable et impossible à quantifier. Cet article passe en revue les problèmes méthodologiques et sémiologiques relatifs à la présence de formes anormales de l'hémoglobine et propose une conduite à tenir standardisée en cas d'hémoglobinopathie