22 research outputs found
Impact of oral melatonin on the electroretinogram cone response
<p>Abstract</p> <p>Background</p> <p>In the eye, melatonin plays a role in promoting light sensitivity at night and modulating many aspects of circadian retinal physiology. It is also an inhibitor of retinal dopamine, which is a promoter of day vision through the cone system. Consequently, it is possible that oral melatonin (an inhibitor of retinal dopamine) taken to alleviate circadian disorders may affect cone functioning. Our aim was to assess the impact of melatonin on the cone response of the human retina using electroretinography (ERG).</p> <p>Methods</p> <p>Twelve healthy participants aged between 18 to 52 years old were submitted to a placebo-controlled, double-blind, crossover, and counterbalanced-order design. The subjects were tested on 2 sessions beginning first with a baseline ERG, followed by the administration of the placebo or melatonin condition and then, 30 min later, a second ERG to test the effect.</p> <p>Results</p> <p>Following oral melatonin administration, a significant decrease of about 8% of the cone maximal response was observed (mean 6.9 ΌV ± SEM 2.0; P = 0.0065) along with a prolonged b-wave implicit time of 0.4 ms ± 0.1, 50 minutes after ingestion.</p> <p>Conclusion</p> <p>Oral melatonin appears to reach the eye through the circulation. When it is administered at a time of day when it is not usually present, melatonin appears to reduce input to retinal cones. We believe that the impact of melatonin on retinal function should be taken into consideration when used without supervision in chronic self-medication for sleep or circadian disorder treatment.</p
Que trouve tâon dans les bulletins et mĂ©moires de la SociĂ©tĂ© Centrale de MĂ©decine VĂ©tĂ©rinaire au temps de Louis Pasteur ?
International audienceA lâĂ©poque de Louis Pasteur, la SociĂ©tĂ© centrale de mĂ©decine vĂ©tĂ©rinaire (ancĂȘtre de lâAcadĂ©mie vĂ©tĂ©rinaire de France) Ă©dite deux pĂ©riodiques influents, les Bulletins et les MĂ©moires de la SociĂ©tĂ© Centrale de MĂ©decine VĂ©tĂ©rinaire. LâĂ©tude des textes parus entre 1844 et 1893 permet de mettre en Ă©vidence les divers sujets qui mobilisent alors les vĂ©tĂ©rinaires. Durant cette pĂ©riode, la profession vĂ©tĂ©rinaire se structure et gagne en notoriĂ©- tĂ©. Lâ« artiste vĂ©tĂ©rinaire » devient un savant, dont les compĂ©tences en matiĂšre dâhygiĂšne et de santĂ© publique sont pleinement reconnues. Les sociĂ©tĂ©s savantes vĂ©tĂ©rinaires commencent Ă publier rĂ©guliĂšrement leurs travaux. Un personnage emblĂ©matique va dominer ce monde vĂ©tĂ©rinaire en plein dĂ©veloppement : Henri Bouley. Converti aux thĂšses de Pasteur alors quâil est Inspecteur GĂ©nĂ©ral des Ăcoles VĂ©tĂ©rinaires, il reste pendant quarante ans secrĂ©taire gĂ©nĂ©ral de la SociĂ©tĂ© centrale de mĂ©decine vĂ©tĂ©rinaire (SCMV) et rĂ©dacteur en chef du principal pĂ©riodique vĂ©tĂ©rinaire : le Recueil de MĂ©decine VĂ©tĂ©rinaire (RMV). Son empreinte va structu- rer les 23 757 pages des Bulletins et des MĂ©moires de la SCMV, accessibles en ligne sur Gallica, bibliothĂšque numĂ©rique de la BibliothĂšque nationale de France. Nous en avons analysĂ© les contenus : comptes rendus de sĂ©ances, questions cliniques, dĂ©bats autour de la profession, sujets imposĂ©s ou libres dĂ©veloppĂ©s dans les MĂ©moires. Nous avons prĂ©sentĂ© sous forme de tableaux synthĂ©tiques lâactivitĂ© de la SCMV et de ses membres au temps de Pasteur, ainsi que lâinventaire chronologique des interactions entre les membres de la SCMV et les membres du comitĂ© Ă©ditorial du RMV. Des figures rendent compte de lâĂ©volution de la profession vĂ©tĂ©rinaire au cours de ces cinquante annĂ©es : enrichissement des savoirs vĂ©tĂ©rinaires, orientation vers le monde scienti- fique et mĂ©dical, contribution de la profession aux travaux de Pasteur et engagement des vĂ©tĂ©rinaires aux cĂŽtĂ©s des mĂ©decins pour la mise en place dâune vĂ©ritable politique de santĂ© publique
A review of in vivo animal studies in retinal prosthesis research
BACKGROUND: The development of a functional retinal prosthesis for acquired blindness is a great challenge. Rapid progress in the field over the last 15 years would not have been possible without extensive animal experimentation pertaining to device design and fabrication, biocompatibility, stimulation parameters and functional responses. This paper presents an overview of in vivo animal research related to retinal prosthetics, and aims to summarize the relevant studies. METHODS: A Pubmed search of the English language literature was performed. The key search terms were: retinal implant, retinal prosthesis, artificial vision, rat, rabbit, cat, dog, sheep, pig, minipig. In addition a manual search was performed based on references quoted in the articles retrieved through Pubmed. RESULTS: We identified 50 articles relevant to in vivo animal experimentation directly related to the development of a retinal implant. The highest number of publications related to the cat (n = 18). CONCLUSION: The contribution of animal models to the development of retinal prosthetic devices has been enormous, and has led to human feasibility studies. Grey areas remain regarding long-term tissue-implant interactions, biomaterials, prosthesis design and neural adaptation. Animals will continue to play a key role in this rapidly evolving field
Comparison of the pig and feline models for full thickness corneal transplantation
Purpose: The goal of this study was to report on the advantages and limitations of the
pig and feline models for experimental in vivo corneal transplantation.
Methods: Ten healthy domestic pigs and ten healthy cats were used. Full thickness
penetrating keratoplasty was performed using autologous (eight cases), allogeneic
(seven cases) or human xenogeneic (three cases) tissue. In two other cases, the
inflammatory response to partial thickness trephination (without transplantation) was
evaluated. Eyes were assessed daily before and after surgery by slit-lamp, pachymetry,
and tonometry. A transparency score ranging from 0 (opaque graft) to 4 (clear graft)
was used, based on the slit-lamp examination. Optical coherence tomography,
histology, and electron microscopy were performed postmortem.
Results: In the pig, the mean (±SD) transparency score for the eight full thickness
grafts was 0.88 ± 0.99, ranging from 0 to 3. In the feline model, the mean
transparency score for the seven uncomplicated grafts was 3.93 ± 0.19, ranging from
3.5 to 4. Both negative controls without endothelium remained opaque at all time.
Intraoperative tendency for iris incarceration into the wound, rapid corneal swelling,
suture cheese wiring, and postoperative intraocular inflammation were the main
factors jeopardizing the functional success of the corneal transplant in the pig model.
Conclusion: Suboptimal functional results were obtained after full thickness corneal
transplantation in the pig model, while in the feline model, the same protocol yielded
uneventful surgeries and clear transplants, with functional results similar to those
achieved in human subjects
La pandĂ©mie dĂ©montre la nĂ©cessitĂ© dâassocier les compĂ©tences vĂ©tĂ©rinaires Ă celles des mĂ©decins et des scientifiques
National audience« Moi qui suis si peu mĂ©decin, si peu vĂ©tĂ©rinaire⊠La science est une⊠C'est l'homme seulement qui en raison de la faiblesse de son intelligence, y Ă©tablit des catĂ©gories. » Extrait du discours de 1880 de Louis Pasteur Ă la SociĂ©tĂ© Centrale de MĂ©decine VĂ©tĂ©rinaire, ancĂȘtre de lâAcadĂ©mie VĂ©tĂ©rinaire de France.La France est le pays de Descartes, de Claude Bernard, fondateur de la mĂ©decine expĂ©rimentale, de Pasteur, ainsi que de Bourgelat, fondateur des premiĂšres Ă©coles vĂ©tĂ©rinaires. MĂȘme si la situation sanitaire de la COVID-19 nâest pas inĂ©dite au vu de la pandĂ©mie de 1969 (grippe de Hong Kong, 40 000 dĂ©cĂšs en France, un million dans le monde), la pandĂ©mie actuelle dĂ©montre la nĂ©cessitĂ© de tirer des enseignements de cette crise pour construire une approche globale basĂ©e sur le concept « One Health » associant santĂ© humaine, santĂ© des Ă©levages et des cultures et santĂ© des Ă©cosystĂšmes. La Covid-19 a remis au premier plan les liens Ă©troits qui existent entre ces diffĂ©rentes santĂ©s et le continuum entre animaux et ĂȘtres humains. Plus de 75 % des agents pathogĂšnes de lâhomme sont issus des animaux. Les coronaviroses, rĂ©pandues dans le rĂšgne animal, font partie de ces maladies des animaux transmissibles Ă lâhomme (zoonoses). Pour les vĂ©tĂ©rinaires, les coronavirus sont des ennemis de tous les jours et leur expertise dans ce domaine et dans la fabrication de vaccins anticoronavirus aurait mĂ©ritĂ© dâĂȘtre plus exploitĂ©e. AuâdelĂ de la prĂ©sence de vĂ©tĂ©rinaires et dâĂ©cologues dans des Ă©quipes de recherche de mĂ©decine humaine, de lâimportante mobilisation de vĂ©tĂ©rinaires praticiens pour la fourniture de matĂ©riels Ă des unitĂ©s de rĂ©animation et de consommables pour les hĂŽpitaux et les Ehpad et de lâautorisation finalement donnĂ©e aux industriels et laboratoires vĂ©tĂ©rinaires de produire des tests PCR et effectuer des analyses Ă grande Ă©chelle, les sciences vĂ©tĂ©rinaires auraient dĂ» ĂȘtre davantage sollicitĂ©es dans lâesprit du concept de santĂ© globale multidisciplinaire. Une collaboration exemplaire entre mĂ©decins et vĂ©tĂ©rinaires : lâĂ©radication sur notre planĂšte de la peste bovine en 2011.Les champs dâapplication et dâexpertise des sciences vĂ©tĂ©rinaires rappelĂ©s par lâAcadĂ©mie VĂ©tĂ©rinaire de France sont nombreux : surveillance sanitaire, biosĂ©curitĂ©, Ă©pidĂ©miologie, virologie, bactĂ©riologie, parasitologie, toxicologie, thĂ©rapeutique, prophylaxie (vaccinologie), sĂ©curitĂ© des aliments, et gestion de crises sanitaires. Ces expertises doivent ĂȘtre lĂ©gitimement et utilement associĂ©es aux commissions gouvernementales qui devront faire le bilan de la gestion de la pandĂ©mie en France.Pour aller plus loin, la crise de la COVID-19 a clairement montrĂ© que notre pays, Ă rebours de sa propre histoire, a rencontrĂ© des difficultĂ©s et a dĂ» surmonter des obstacles pour associer les compĂ©tences vĂ©tĂ©rinaires Ă celles des mĂ©decins et des scientifiques. Dâautres pays dont l'Allemagne les ont associĂ©es dĂšs le dĂ©part, en particulier pour permettre de rĂ©aliser rapidement des tests PCR.Les problĂ©matiques de la santĂ© humaine, de la santĂ© des espĂšces domestiques (Ă©levages et cultures) et de la santĂ© de la faune et de la flore sauvages (biodiversitĂ© et santĂ© des Ă©cosystĂšmes) sont aujourdâhui gĂ©rĂ©es de maniĂšre cloisonnĂ©e par plusieurs ministĂšres au dĂ©triment des Ă©normes synergies potentielles pour une approche globale associant les diffĂ©rentes santĂ©s.Construire une approche globale de la santĂ© nĂ©cessitera de dĂ©passer la simple incantation du concept « One-Health » » et exigera une vĂ©ritable collaboration transdisciplinaire, une abolition des hĂ©gĂ©monies dâĂ©coles et de pensĂ©es. ImpĂ©rieuse est la nĂ©cessitĂ© de dĂ©velopper les synergies entre lâagriculture, lâalimentation, la santĂ© et lâenvironnement. La volontĂ© politique doit ĂȘtre nationale et internationale pour vĂ©ritablement intĂ©grer les dimensions mĂ©dicale, vĂ©tĂ©rinaire et Ă©cologique de la santĂ©. Cette dĂ©marche arrive au mĂȘme moment que deux rĂ©formes majeures en cours sur lesquelles elle doit sâadosser : la rĂ©forme de lâenseignement de la mĂ©decine et la loi de programmation pluriannuelle de la recherche. Cette vision globale doit sâinscrire dans le futur plan national santĂ©-environnement en y associant plus Ă©troitement le ministĂšre de lâagriculture.Quelques exemples. Au niveau national : dĂ©cloisonner lâenseignement dans les Ă©coles vĂ©tĂ©rinaires et agronomiques, les facultĂ©s de mĂ©decine et celles des sciences Ă©cologiques, si divisĂ©es car appartenant Ă des ministĂšres diffĂ©rents, et renforcer leur capacitĂ© Ă former des chercheurs de premier ordre collaborant avec les cliniciens. Un GNES (groupe national environnement santĂ©) pourrait Ă©galement ĂȘtre mobilisĂ© avec des fonds publics et privĂ©s rĂ©unissant et mobilisant des scientifiques de tous horizons notamment issus dâinstituts de recherche de mĂ©decine humaine, de santĂ© animale, de santĂ© vĂ©gĂ©tale et environnementale. Ce groupe devrait permettre aux professionnels et aux administrations de mieux apprĂ©hender les enjeux du futur : climat, biodiversitĂ©, dĂ©veloppement compatible avec les limites planĂ©taires. Au niveau de la gouvernance internationale, les trois organisations OMS-FAO-OIE en sont restĂ©es Ă un principe de collaboration sans programme dâaction spĂ©cifique et financĂ©. Il est dĂ©sormais urgent pour mieux se prĂ©parer et rĂ©duire les risques de pandĂ©mies dâamĂ©liorer la production en commun des savoirs des acteurs concernĂ©s. Certains Ă©voquent, au sens Ă©pistĂ©mique, les concepts dâEco Health, Global Health ou Planetary Health. Au niveau international, cette approche holistique pourrait, Ă lâinstar de ce qui a Ă©tĂ© fait pour le changement climatique (GIEC), passer par la crĂ©ation dâun groupe dâexperts intergouvernemental sur la santĂ© (GIES) ; il pourrait ĂȘtre, selon lâAcadĂ©mie VĂ©tĂ©rinaire de France, une Ă©manation de lâAlliance OMS-FAO-OIE associĂ©e au PNUE (Programme des Nations-Unies pour lâEnvironnement) et ĂȘtre mandatĂ© par le SecrĂ©taire gĂ©nĂ©ral des Nations-Unies
Determination of Morphological, Biometric and Biochemical Susceptibilities in Healthy Eurasier Dogs with Suspected Inherited Glaucoma
International audienceIn both humans and dogs, the primary risk factor for glaucoma is high intraocular pressure (IOP), which may be caused by iridocorneal angle (ICA) abnormalities. Oxidative stress has also been implicated in retinal ganglion cell damage associated with glaucoma. A suspected inherited form of glaucoma was recently identified in Eurasier dogs (EDs), a breed for which pedigrees are readily available. Because of difficulties in assessing ICA morphology in dogs with advanced glaucoma, we selected a cohort of apparently healthy dogsfor the investigation of ICA morphological status, IOP and plasma concentrations of oxidative stress biomarkers. We aimed to establish correlations between these factors, to identify predictive markers of glaucoma in this dog breed. A cohort of 28 subjects, volunteered for inclusion by their owners, was selected by veterinary surgeons. These dogs were assigned to four groups: young males, young females (1â3 years old), adult males and adult females (4â8 years old). Ocular examination included ophthalmoscopy, tonometry, gonioscopy, biometry and ultrasound biomicroscopy (UBM), and the evaluation of oxidative stress biomarkers consisting of measurements of plasma glutathione peroxidase (GP) activity and taurine and metabolic precursor (methionine and cysteine) concentrations in plasma. The prevalence of pectinate ligament abnormalities was significantly higher in adult EDs than in young dogs. Moreover, in adult females, high IOP was significantly correlated with a short axial globe length, and a particularly large distance between Schwalbe's line and the anterior lens capsule. GP activity levels were significantly lower in EDs than in a randomized control group of dogs, and plasma taurine concentrations were higher. Hence, ICA abnormalities were associated with weaker antioxidant defenses in EDs, potentially counteracted by higher plasma taurine concentrations. This study suggests that EDs may constitute an appropriate canine model for the development of glaucoma. This cohort will be used as a sentinel for longitudinal monitoring