Visual evoked potentials (VEP) and electroretinography (ERG) are known as objective and quantitative methods to analyse the functionality of visual pathways. Separately used in the ophthalmologic clinic to evaluate retina (ERG) or central visual pathways (VEP), this study designs a combined protocol with both techniques recorded in one session, and also proposes a normal data base for beagle. Twelve beagle dogs were used to design a 90-minutes protocol by using a mydriatic drug, anaesthetic protocol and a proper electrode placement. Flash stimulation technique was selected, and monocular stimulations were recorded. A large number of parameters regarding light stimulation, recording, amplification, and signal averaging were also controlled. The sequence of testing was: VEP, ERG scotopic and ERG photopic. Dogs were dark-adapted for at least 20 minutes to record VEP and scotopic ERG, and evaluated in a darkened room. Photopic ERG was tested with a prior 10 minutes light-adaptation, in an illuminated room. Characteristic waveforms were obtained. Four peaks were present and named as: P1, N1, P2, and N2 for VEP recordings. However, in ERG recordings, typical a-wave and b-wave were registered, but c-wave was not present. The proposed electrodiagnostic combined protocol in this study allows the assessment of the visual pathway integrity from retina to visual cortex in dogs. This procedure allows to collect the information in the most simple, shorter and less stressful manner for the patient. RESUMEN Los potenciales evocados visuales (PEV) y la electrorretinografía (ERG) son dos métodos de análisis objetivo y cuantitativo de la funcionalidad de las vías visuales, que se realizan de forma independiente en la clínica oftalmológica para la evaluación de la retina o de las vías visuales centrales, respectivamente. El presente trabajo propone un protocolo clínico combinado de ambas técnicas en una única sesión, además de una base de datos normales para la raza beagle. Se emplearon 12 beagles para diseñar un protocolo de 90 minutos de duración que incluía el uso de midriáticos, protocolo anestésico y colocación apropiada de electrodos de registro. La técnica de estimulación luminosa seleccionada fueron flashes de luz blanca emitidos de modo monocular. Diversos parámetros de estimulación, registro, amplificación y filtrado fueron calibrados. La secuencia de estimulación fue: PEV, ERG escotópico y ERG fotópico. Las 2 primeras técnicas se realizaron en oscuridad con previa adaptación ocular de 20 minutos, mientras que la última se realizó con luminosidad ambiente y previa adaptación a la luz de 10 minutos. La gráfica de PEV mostró 4 picos (P1, N1, P2, N2), mientras que el ERG mostró las típicas ondas (a y b) sin presencia de onda-c. Este procedimiento permite recoger los registros de ambas pruebas electrodiagnósticas de la manera más simple y menos estresante para el paciente canino, y propone una base de datos normales actualizada para el beagle. Palabras clave: electrodiagnóstico, electrorretinografía, potenciales evocados visu...
Abstract— —A wide range of tumours may affect the ocular structures in many different animals and there is a marked difference in incidence of both common and uncommon varieties. One of the most common and important neoplasms of the domestic animal is the squamous cell carcinoma of the cow. Intraocular tumours are not common, retinoblastoma for example being extremely rare. Ocular tumours in animals may be classified on the same basis as their human counterparts. SUMMARY It has been recorded that all the spontaneous tumours in general that affect man with the exception of chorion carcinoma can also occur in animals. While tumours of the domestic animals have received most attention in the literature, there are also reports of tumours in wild animals. It is clear from the numerous articles on the tumours of domestic animals that there exists a marked difference in the incidence of both common and uncommon neoplasms. Tumours are found less frequently in animals which are often slaughtered for food at relatively early ages than in domestic pets which often survive into old age, and in laboratory animals which are often under close observation for long periods. One of the most common and important ocular tumours of the domestic animal is the squamous cell carcinoma of the conjunctiva in the cow. Intraocular tumours are not common, retinoblastoma for example being extremely rare. The ocular tumours occurring in animals are classified and reviewed in this paper, examples of these tumours are illustrated, and their incidence and aetiology are discussed. Résumé— —On connait chez de nombreuses espèces animales une grande diversité de tumeurs des organes de la vue, et la morbidité de ces tumeurs varie sensiblement, qu'il s'agisse de formes fares ou répandues. L'une des plus fréquentes et des plus importantes néoplasies observées chez les animaux domestiques est le carcinome à cellules squameuses, rencontré chez la vache. Les tumeurs intraoculaires sont peu fréquentes; les rétinoblastomes notamment sont extrêmement rares. Les tumeurs de l'oeil rencontrées chez les animaux sont susceptibles du même classement que les néoplasies analogues constatées chez l'homme. Zusammenfassung— —Die verschiedensten Tumoren können die Augenstrukturen bei vielen verschiedenen Tieren befallen, und es besteht ein deutlicher Unterschied hinsichtlich der Häufigkeit gewöhnlicher und seltener Arten. Eines der häufigsten und wichtigsten Neoplasmen des Haustiers ist das Plattenepithelcarcinom der Kuh. Intraoculare Tumoren sind nicht häufig, das Retinoblastom zum Beispiel ist äusserst selten. Die Augentumoren bei Tieren können auf der gleichen Basis wie die bein Menschen klassifiziert werden.
The term "diffuse infiltrating retinoblastoma" was introduced by Ashton (1958) to describe a form of retinoblastoma which did not produce a tumour mass within the retina.Although Manschot (1956) and Weizenblatt (I957) had described such cases previously, they did not recognize the condition as a distinct entity. Schofield (1960) described four cases of this type of retinoblastoma which presented with a hypopyon, and neoplastic cells were demonstrated in the anterior chamber paracenteses.The purpose of the present paper is to describe a further case of this type of tumour, and to review the ten cases which have been seen in the Pathology Department of this Institute, including the four described by Schofield (I960). Case report CLINICAL FEATURESA mentally defective boy aged io years was admitted to hospital with the history of pain in the right eye of several months' duration. There were no other complaints. Ophthalmological examination of the right eye showed a hypopyon, multiple whitish nodules on the iris, and white vitreous exudates; the left eye was normal. Radiographs of the chest showed no abnormality. TREATMENTSteroid therapy was begun, but glaucoma, corneal oedema, and an inferior limbal staphyloma ensued. The eye was enucleated. PATHOLOGYMacroscopical examination showed enlargement of the globe (antero-posterior diameter 32 mm; horizontal diameter 29 mm.). There was an inferior limbal staphyloma (Fig. i, opposite), and exudate was present in the anterior chamber and the vitreous. The retina was diffusely thickened but there was no evidence of a tumour mass (Fig. 2, opposite). The optic disc was cupped.Microscopical examination showed diffuse infiltration of the retina by a retinoblastoma, with no evidence of a tumour mass. The tumour was involving all the layers of the retina and was composed of cells having a little pinkish cytoplasm and hyperchromatic nuclei of varying shapes and sizes. Individual cell necrosis was seen and mitotic figures were fairly common, but there was no evidence of rosette formation (Fig. 3, opposite, and Fig. 4, overleaf).Discrete foci of tumour cells were seen near the internal limiting membrane of the retina (Fig. 5, overleaf) and extension into the anterior vitreous had occurred, some of the cells at this site being viable but most of them being necrotic (Fig. 6, overleaf).Posteriorly tumour cells had extended into the cupped optic disc but not into the nerve. Anteriorly extension had occurred on to the pars plana (Fig. 7) and ciliary epithelium (Fig. 8), into the iris leaf on one side, and on to both its anterior and posterior surfaces (Figs 9 and io). Tumour cells had then extended on to the posterior surface of the cornea, the filtration angle on this side having
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