Ciliary body myxoid epithelioid sarcoma in a cat: a case report.

BACKGROUND: The majority of primary, intraocular tumors in cats originate from the uvea and include feline diffuse iris melanoma, lymphoma, and iridociliary epithelial adenoma or adenocarcinoma. In this case report, we describe for the first time the clinical, histological, and immunohistochemical findings of a rare myxoid intraocular neoplasm arising from the ciliary body in a cat. CASE PRESENTATION: A 14-year-old, female, spayed domestic shorthaired cat was presented for evaluation of discolouration of the right eye. Upon examination, a clear to light whitish-tan, bubble-shaped intraocular mass adherent to the inferior ciliary body and extending into the anterior chamber was noted. Within five weeks, the tumor was significantly larger and the eye had developed secondary glaucoma so was enucleated. Light microscopic examination of the globe revealed a multinodular, hypocellular neoplasm arising from the ciliary body composed of interwoven spindle cells embedded in abundant amounts of a lightly basophilic myxoid matrix. Neoplastic cells exhibited strong immunoreactivity for cytokeratin while also showing moderate to strong immunoreactivity to vimentin. A diagnosis was therefore made of an unusual intraocular myxoid epithelioid sarcoma arising from the ciliary body. CONCLUSIONS: Although apparently exceedingly rare, epithelioid myxosarcoma should be included as a differential diagnosis for intraocular tumors in cats and they represent a clinical, histologic, and immunohistochemical diagnostic challenge. Early surgical intervention should be considered to prevent local invasion and ascension to the brain.

Histologic, immunohistochemical, and scanning electron microscopic comparison of pre-iridal monocellular and fibrovascular membranes in normal and glaucomatous canine globes.

OBJECTIVES: (i) To evaluate immunohistochemical labeling of pre-iridal monocellular and fibrovascular membranes and (ii) describe the light and scanning electron microscopic (SEM) characteristics of these membranes in glaucomatous and normal/control canine globes. MATERIALS AND METHODS: All globes were evaluated with light microscopy. Immunohistochemical labeling for CD18, Smooth muscle actin (SMA), and CD117 was completed on 40 canine globes with congenital/anterior segment dysgenesis-associated glaucoma (n = 10), primary/goniodysgenesis-associated glaucoma (n = 10), secondary glaucoma (n = 10), and normal/control globes (n = 10). SEM was completed on 10 globes: 5 with monocellular membranes, 3 with fibrovascular membranes, and 2 without a histologically detectable membrane. RESULTS: Monocellular membranes were detected in all normal/control globes with light microscopy and appeared to be morphologically very similar to those in diseased globes. CD18 labeling was detected in 9/10 monocellular membranes in normal/control globes, 15/23 monocellular, and 7/8 fibrovascular membranes in globes with glaucoma. SMA and CD117 labeling was not detected in monocellular membranes of normal/control globes. SMA was expressed in 10/23 monocellular and 7/8 fibrovascular membranes of glaucomatous globes. CD117 was expressed in 7/23 monocellular and 5/8 fibrovascular membranes of glaucomatous globes. SEM of monocellular membranes revealed a continuous sheet of mostly spindle cells and few individual round cells that extended over the anterior iris face in normal/control and all glaucomatous globes. CONCLUSION: Pre-iridal monocellular membranes are a normal component of the anterior iris surface, and CD18 immunoreactivity suggests some cells within these are of leukocytic origin. SMA and CD117 labeling of monocellular membranes in glaucomatous, but not normal/control globes, suggest metaplastic cellular change secondary to intraocular pathology related to glaucoma.

In vivo imaging comparison of unilateral circular retinal plaques in retriever dogs to dysplasia and detachment in the English Springer Spaniel.

PURPOSE: To compare the scanning laser ophthalmoscopy (SLO), optical coherence tomography (OCT), and fluorescein angiography (FA) findings in retrievers with a single unilateral circular retinal plaque to those of an English springer spaniel with bilateral retinal dysplasia. PROCEDURES: A retrospective record review identified three dogs with circular retinal plaques that underwent SLO and OCT; in two of the three dogs, FA was also completed. Morphologic changes, lesion measurements, and angiogram characteristics were documented. An English springer spaniel with bilateral retinal dysplasia that had undergone SLO, OCT, and FA was used for comparison. RESULTS: Scanning laser ophthalmoscopy of the retriever dogs revealed circular retinal plaques with a dark periphery located in the tapetal retina. OCT revealed a thickening of the nerve fiber layer corresponding to the circular pattern observed on SLO. Within the circular plaque, the retina was predominantly of normal architecture. FA revealed variable hypofluorescence of both the rim and the center of the circular lesion throughout the early angiogram phases. In the late recirculation phase, small multifocal areas of hyperfluorescence were observed. OCT of geographic retinal dysplasia in the English springer spaniel revealed disorganization of both inner and outer retinal layers, and retinal detachment. CONCLUSIONS: Circular plaques observed in the tapetal retina are predominantly formed by a thickening of inner retina, while retinal dysplasia has disorganization of both inner and outer retinal layers. Further etiologic research is needed, including pedigree mapping to determine whether retinal plaques are an acquired or inherited condition.

Evaluation of retinal morphology of canine sudden acquired retinal degeneration syndrome using optical coherence tomography and fluorescein angiography.

PURPOSE: To describe the optical coherence tomography (OCT) and fluorescein angiography changes in dogs with sudden acquired retinal degeneration syndrome (SARDS). METHODS: Retinal OCT was performed on 10 SARDS dogs and eight control dogs. Tomograms were collected in four quadrants around the optic nerve. Measurements were collected from the photoreceptor layer, the outer nuclear layer, the outer retina, the inner retina and the whole retina thickness in all quadrants. Sodium fluorescein was injected intravenously and serial fundic photographs were collected for a 5 minute period post-injection. RESULTS: In all quadrants, the outer nuclear layer (dorsal temporal P = 0.0000, dorsal nasal P = 0.0001, ventral temporal P = 0.0002, ventral nasal P = 0.000) and outer retina (dorsal temporal P = 0.0001, dorsal nasal P = 0.0002, ventral temporal P = 0.0054, ventral nasal P = 0.0084) measurements were significantly decreased in SARDS dogs. The whole retina thickness was significantly decreased in the dorsal temporal (P = 0.0082) and ventral temporal (P = 0.0428) retina. There were no significant differences in the photoreceptor layer thickness or inner retinal thickness between SARDS and control dogs. All SARDS dogs had a loss of definition of all of the photoreceptor bands on OCT. Two SARDS dogs had multifocal small retinal detachments and one of these dogs exhibited fluorescein leaking at the detachment sites. CONCLUSIONS: The significant reduction in the outer nuclear layer and the loss of band signals in the photoreceptor layers in dogs with SARDS identified on OCT support the previous histopathology findings. Small detachments may occasionally be detected on OCT and they may leak fluorescein.

A review of Horner's syndrome in small animals.

Horner's syndrome arises from dysfunction of the oculosympathetic pathway and is characterized by miosis, enophthalmos, protrusion of the third eyelid, and ptosis. It has been recognized in a wide variety of breeds and ages in small animal patients. The oculosympathetic pathway is a 3-neuron pathway. The central/first order neuron arises from the hypothalamus and extends down the spinal cord. The preganglionic/second order neuron arises from the first 3 thoracic spinal cord segments and travels through the thorax and cervical region until it synapses at the cranial cervical ganglion. The postganglionic/third order neuron travels from this ganglion to the orbit. Topical application of cocaine is the gold standard for differentiating Horner's syndrome from other causes of miosis. Topical 1% phenylephrine allows for identification of a post-ganglion Horner's syndrome. Numerous etiologies have been reported for Horner's syndrome, but idiopathic disease is most common. Ancillary diagnostics include otoscopic examination, thoracic radiographs, or advanced imaging. Treatment and prognosis are determined by the etiology.

Examen du syndrome de Horner chez les petits animaux. Le syndrome de Horner provient d'une dysfonction de la voie oculo-sympathique et est caractérisée par la miose, l'enophtalmie, la protrusion de la troisième paupière et la ptose. Elle a été reconnue chez une grande variété de races et d'âges chez les patients petits animaux. La voie oculo-sympathique est une voie à trois neurones. Le neurone central/de premier ordre provient de l'hypothalamus et s'étend vers le bas sur la colonne vertébrale. Le neurone préganglionnaire/de deuxième ordre provient des trois premiers segments thoraciques de la colonne vertébrale et se déplace dans le thorax et la région cervicale jusqu'à la synapse au ganglion cervical crânien. Le neurone postganglionnaire/de troisième ordre se déplace de ce ganglion jusqu'à l'orbite. L'application topique de cocaïne est le test de référence pour la différenciation du syndrome de Horner des autres causes de miose. La phényléphrine topique 1 % permet l'identification d'un syndrome de Horner postganglionnaire. Plusieurs étiologies ont été signalées pour le syndrome de Horner, mais la maladie idiopathique est la plus commune. Les diagnostics auxiliaires incluent l'examen otoscopique, des radiographies thoraciques ou une imagerie avancée. Le traitement et le pronostic sont déterminés par l'étiologie.(Traduit par Isabelle Vallières).

Peripheral cranial neuropathies consistent with cavernous sinus syndrome caused by extracranial nasopharyngeal lymphoma in a cat.

Cavernous sinus syndrome is a unique constellation of cranial nerve deficits occurring typically as a result of pathologic infiltration of the cavernous sinus, which is located in the lateral sellar compartment of the calvarium. This case report describes a polyneuropathy consistent with cavernous sinus syndrome as a result of a lesion outside of the cavernous sinus. The cat was presented with right internal and external ophthalmoplegia, loss of right corneal sensation, inspiratory stridor, dysphagia, dysphonia, tongue weakness, and weight loss. Magnetic resonance imaging identified a large nasopharyngeal mass along the base of, but without extension into, the calvarium. The histologic diagnosis was nasopharyngeal lymphoma. Focal extracranial masses should be considered as differential diagnoses for multiple cranial nerve deficits, including the constellation of clinical signs recognized as cavernous sinus syndrome.

Neuropathies crâniales périphériques compatibles avec un syndrome du sinus caverneux causé par un lymphome nasopharyngé extra-crânial chez un chat. Le syndrome du sinus caverneux est une constellation unique de déficits des nerfs crâniens se produisant typiquement comme le résultat d'une infiltration pathologique du sinus caverneux, qui est situé dans le compartiment sellaire latéral du calvarium. Le présent rapport de cas décrit une polyneuropathie compatible avec un syndrome du sinus caverneux résultant d'une lésion à l'extérieur du sinus caverneux. Le chat fut présenté avec une ophtalmoplégie interne et externe droit, perte de sensation au niveau de la cornée droite, stridor inspiratoire, dysphagie, dysphonie, faiblesse de la langue, et perte de poids. Un examen d'imagerie par résonnance magnétique permis d'identifier une large masse nasopharyngée suivant la base du calvarium, mais sans extension à l'intérieur. Le diagnostic histologique en fut un de lymphome nasopharyngé. Les masses focales extra-crâniales devraient être considérées dans le diagnostic différentiel lors de déficits de plusieurs nerfs crâniens, incluant la multitude de signes cliniques reconnus comme le syndrome du sinus caverneux.(Traduit par Dr Serge Messier).

Odontogenic parakeratinized cyst resulting in exophthalmos and palatine, maxillary, and zygomatic bone erosion in a dog.

A novel case of a canine odontogenic parakeratinized cyst (COPC) that resulted in exophthalmos and palatine, maxillary, and zygomatic bone erosion in a 5-year-old Chihuahua dog is reported. Final diagnosis was aided by cross-sectional imaging (magnetic resonance imaging and computed tomography) and confirmed with histologic examination of the cyst wall.

Bilateral retinoschisis in a dog: A veterinary clinical application for optical coherence tomography.

A 11-year-old neutered male Labrador retriever-cross dog was presented to the University of Missouri-Columbia Veterinary Ophthalmology Service for subtle visual deficits. Indirect ophthalmoscopy revealed a smooth, bullous elevation in the superior-temporal retina OU. Optical coherence tomography (OCT) performed OU showed inner retinal separation consistent with retinoschisis. Electroretinography (ERG) revealed markedly reduced b-wave amplitudes in the more severely affected eye (OD) compared with the less severely affected eye (OS). The most notable reductions were in the rod response and 30-Hz flicker b-waves OD which were approximately 50% of the corresponding amplitudes OS. Implicit times, particularly the a-wave implicit times, were noticeably longer OD compared with OS. Lesions remained unchanged over 4 months at which time the dog was humanely euthanized for reasons unrelated to the ocular disease. Significant light microscopic ocular findings were bilateral superior temporal peripheral retinoschisis. The separation of the retinal tissue was similar between eyes and effectively divided the outer plexiform layer. In addition, thinning of the surrounding retinal layers was present. To the authors' knowledge, this is the first case of canine retinoschisis diagnosed with OCT, evaluated with electroretinography, and confirmed with light microscopic examination. History, clinical, and diagnostic findings, with the absence of disease progression over time, are analogous with cases of acquired senile retinoschisis in humans.

Primary bilateral corneal nerve sheath neoplasm in a dog.

A 15-year-old, neutered male, Shih Tzu cross developed progressive corneal stromal thickening and vascularization of the right eye, and 5 months later, of the left eye. Both eyes became blind due to extensive corneal opacification and were enucleated. Light microscopic examination revealed a diffuse corneal infiltrate of neoplastic mesenchymal cells, and immunohistochemistry revealed diffuse cytoplasmic vimentin immunoreactivity and variable cytoplasmic and nuclear immunoreactivity for S100 in the neoplastic cells. Transmission electron microscopy revealed desmosomes between contiguous cells, thread-like cytoplasmic processes coated with basement membrane, extracellular bundles of collagen, and axonal degeneration consistent with features of a nerve sheath neoplasm. This is the first report of primary, bilateral corneal nerve sheath sarcoma in a canine.

Effect of prolonged photoperiod on ocular tissues of domestic turkeys.

OBJECTIVE: The objective of this study is to investigate the structural and functional ocular changes that develop in turkeys exposed to a photoperiod of 23 h of light (23L) compared with a photoperiod of 14 h of light (14L). PROCEDURES: Ten-day-old Nicholas heavy strain poults were exposed to either a 14L or 23L photoperiod. Between 16 and 18 weeks of age, equal numbers of turkeys per treatment group underwent ophthalmic examination (biomicroscopy, indirect ophthalmoscopy) (n = 14), refractometry (n = 20), keratometry (n = 20), tonometry (n = 20), and full-field electroretinography (ERG) (n = 14). Postmortem analyses included orbital magnetic resonance imaging (MRI) (n = 10) and light microscopy (n = 24) at 18 weeks of age. RESULTS: Autorefraction revealed a median of -0.13 for sphere in both groups (P = 0.69), which is approximately emmetropia. The radius of curvature of the cornea was significantly higher (P = 0.0001) and the refractive power of the cornea was significantly lower (P = 0.0001) in the 23L group. The astigmatic power was significantly greater in the 23L group (P = 0.0001). Mean intraocular pressure did not differ between groups (P = 0.085). Turkeys from the 23L group had significantly larger globes in nasotemporal (P = 0.0007), dorsoventral (P = 0.015), and anterioposterior (P = 0.021) directions, and anterior chambers were more shallow (P = 0.0002). ERGs revealed the 23L group to have lower a- and b-wave amplitudes and significantly lower cone flicker amplitudes (P = 0.0008). Light microscopic examination revealed 23L turkeys to have significantly decreased numbers of nuclei in the outer nuclear layer (P = 0.0001) and inner nuclear layer (P = 0.0186), and decreased choroidal thickness (P = 0.0008). The prevalence of cataract in the 23L group was significantly higher (P = 0.001). CONCLUSIONS: Exposing turkeys to a prolonged photoperiod induces significant ocular disease.

Sudden acquired retinal degeneration syndrome in western Canada: 93 cases.

This study reviewed clinical data from dogs diagnosed with sudden acquired retinal degeneration syndrome (SARDS) in western Canada. Medical records from the Western College of Veterinary Medicine from 2002 to 2016 showed that 93 cases of SARDS were diagnosed based on presentation for sudden blindness and a bilaterally extinguished electroretinogram. The most common pure breeds were the miniature schnauzer, dachshund, and pug. The mean age at diagnosis was 8.1 years and males and females were equally affected. Most of the dogs were presented with normal non-chromatic, but abnormal chromatic pupillary light reflexes. The incidence of retinal degeneration as detected via ophthalmoscopy increased over time after SARDS diagnosis. Polyuria, polydipsia, polyphagia, weight gain, elevated liver enzyme values, isosthenuria, and proteinuria were common clinical and laboratory findings. Chromatic pupillary light reflex testing may be more valuable than non-chromatic pupillary light testing in detecting pupil response abnormalities in dogs with SARDS, although electroretinography remains the definitive diagnostic test.

Syndrome de la rétine silencieuse dans l'Ouest canadien : 93 cas. Cette étude a examiné les données cliniques provenant de chiens diagnostiqués avec le syndrome de la rétine silencieuse (syndrome de cécité soudaine acquise) dans l'Ouest canadien. Les dossiers médicaux du Western College of Veterinary Medicine de 2002 à 2016 ont montré que 93 cas du syndrome de la rétine silencieuse ont été diagnostiqués en se basant sur la présentation pour une cécité soudaine et un électrorétinogramme bilatéral sans incandescence. Les races les plus communes étaient le Schnauzer miniature, le Dachshund et le Pug. L'âge moyen au diagnostic était de 8,1 ans et les mâles et les femelles étaient également affectés. La plupart des chiens présentaient des réflexes pupillaires normaux à la lumière non chromatique mais des réflexes anormaux à la lumière chromatique. L'incidence de la dégénération rétinienne détectée par l'ophtalmoscopie a augmenté au fil du temps après le diagnostic du syndrome de la rétine silencieuse. La polyurie, la polydipsie, la polyphagie, le gain de poids, des valeurs d'enzymes hépatiques élevées, l'isosthénurie et la protéinurie étaient des résultats cliniques et de laboratoire communs. Le réflexe à la lumière pupillaire chromatique peut être plus utile que le test de la lumière pupillaire non chromatique pour détecter les anomalies de la réponse pupillaire chez les chiens atteints du syndrome de la rétine silencieuse, quoique l'électrorétinographie demeure le test diagnostique définitif.(Traduit par Isabelle Vallières).

Equine recurrent uveitis in western Canadian prairie provinces: A retrospective study (2002-2015).

The objectives of this study were to determine the demographics of horses with equine recurrent uveitis (ERU) presenting to the Western College of Veterinary Medicine and to describe and compare the prognosis of ERU in the Appaloosa with that in other breeds. Horses diagnosed with ERU by a veterinary ophthalmologist between 2002 and 2015 were included. Eye lesions were classified as mild, moderate, or severe based on clinical manifestations. Breed, age, severity, blindness, and final outcome were evaluated. Thirty-two horses fit the inclusion criteria; 62.5% were Appaloosas. Mean age at presentation was 12.13 ± 4.6 years. Equine recurrent uveitis was bilateral in 93.6% of horses and was severe in 59.4% of eyes at presentation. Bilateral blindness was present in 59.4% of horses at last follow-up. Of 27 horses available for follow-up, 63% were euthanized due to ERU. No significant differences in age, severity, blindness, or rate of euthanasia were noted between Appaloosas and other breeds. The Appaloosa is at increased risk for ERU, which is a devastating ocular disease.

Uvéite équine récurrente dans les provinces de l'Ouest canadien : étude rétrospective (2002­2015). L'objectif de cette étude consistait à déterminer les données démographiques des chevaux atteints d'uvéite équine récurrente (UER) présentés au Western College of Veterinary Medicine et de décrire et de comparer le pronostic de l'UER chez les chevaux Appaloosa avec celui des autres races. Les chevaux diagnostiqués entre 2002 et 2015 comme étant atteints de l'UER par un ophtalmologiste vétérinaire ont été inclus. Les lésions à l'œil étaient classées comme étant légères, modérées ou graves selon les manifestations cliniques. La race, l'âge, la gravité, la cécité et le résultat final ont été évalués. Trente-deux chevaux correspondaient aux critères d'inclusion : 62,5 % étaient des chevaux Appaloosa. L'âge moyen à la présentation était de 12,13 ans ± 4,6 années. L'uvéite équine récurrente était bilatérale chez 93,6 % des chevaux et était grave pour 59,4 % des yeux à la présentation. La cécité bilatérale était présente chez 59,4 % des chevaux au dernier suivi. Parmi les 27 chevaux disponibles pour le suivi, 63 % ont été euthanasiés en raison de l'UER. Aucune différence significative au niveau de l'âge, de la gravité, de la cécité ou du taux d'euthanasie n'a été signalée entre les chevaux Appaloosa et les autres races. Les chevaux Appaloosa présentent un risque accru d'UER, qui est une maladie oculaire dévastatrice.(Traduit par Isabelle Vallières).

Congenital nuclear cataracts in a Holstein dairy herd.

This report describes congenital nuclear cataracts and posterior lenticonus in a closed purebred Holstein dairy herd in Canada. Ophthalmic examinations were completed on 30 male and 249 female cattle aged newborn to 10 years old. Nutritional, infectious, and toxic etiologies were investigated. Necropsies of 3 affected calves were performed and eyes of 2 additional affected calves were examined with light microscopy. Bilateral nuclear cataracts were identified in 53/279 (19%) animals. Additional congenital anomalies observed included posterior lenticonus, iris to lens persistent pupillary membranes (n = 7), and lenticular colobomata (n = 1). Heifers did not give birth to calves with congenital nuclear cataracts (0/105), whereas the incidence of affected calves born to multiparous cows was 31% (53/171). The animals with nuclear cataracts ranged from newborn to 8 years old. The cataracts appeared to be non- or minimally progressive. Light microscopic examination of 10 affected globes confirmed nuclear cataract with posterior lenticonus (n = 10). Pedigree analysis was inconclusive. Polymerase chain reaction and sequence analysis for the NID1 gene deletion were negative. The etiology of the congenital lenticular anomalies was not determined.

Cataractes nucléaires congénitales dans un troupeau laitier Holstein. Cette étude rapporte les résultats d'une enquête sur des cataractes nucléaires congénitales et des lenticônes postérieurs dans un troupeau laitier fermé Holstein pur-sang au Canada. Des examens ophtalmiques ont été réalisés sur 30 bovins mâles et 249 bovins femelles qui étaient âgés de nouveau-né à 10 ans. Les étiologies nutritionnelles, infectieuses et toxiques ont été étudiées. Des nécropsies ont été effectuées pour trois veaux touchés et les yeux de deux veaux affectés additionnels ont été examinés à l'aide de microscopie photonique. Des cataractes nucléaires bilatérales ont été identifiées chez 53/279 (19 %) des animaux. Les anomalies congénitales additionnelles observées incluaient le lenticône postérieur, des membranes pupillaires persistantes de l'iris à la lentille (n = 7) et le colobome lenticulaire (n = 1). Les taures n'ont pas donné naissance à des veaux avec des cataractes nucléaires congénitales (0/105), tandis que l'incidence des veaux affectés nés de vaches multipares était de 31 % (53/171). Les animaux avec des cataractes nucléaires étaient âgés de nouveau-né à 8 ans. Les cataractes semblaient être non progressives ou minimalement progressives. Un examen à l'aide d'un microscope photonique de 10 globes affectés a confirmé la cataracte nucléaire avec un lenticône postérieur (n = 10). L'analyse du pedigree a été non-concluante. Une réaction d'amplification en chaîne par la polymérase et une analyse de séquence pour la suppression du gène NID1 ont été négatives. L'étiologie des anomalies lenticulaires congénitales n'a pas été déterminée.(Traduit par Isabelle Vallières).

Redundant contribution of a Transient Receptor Potential cation channel Member 1 exon 11 single nucleotide polymorphism to equine congenital stationary night blindness.

BACKGROUND: Congenital stationary night-blindness (CSNB) is a recessive autosomal defect in low-light vision in Appaloosa and other horse breeds. This condition has been mapped by linkage analysis to a gene coding for the Transient Receptor Potential cation channel Member 1 (TRPM1). TRPM1 is normally expressed in the ON-bipolar cells of the inner nuclear layer of the retina. Down-regulation of TRPM1 expression in CSNB results from a transposon-like insertion in intron 1 of the TRPM1 gene. Stop transcription signals in this transposon significantly reduce TRPM1 primary transcript levels in CSNB horses. This study describes additional contributions by a second mutation of the TRPM1 gene, the ECA1 108,249,293 C > T SNP, to down-regulation of transcription of the TRPM1 gene in night-blind horses. This TRPM1 SNP introduces a consensus binding site for neuro-oncological ventral antigen 1 (Nova-1) protein in the primary transcript. Nova-1 binding disrupts normal splicing signals, producing unstable, non-functional mRNA transcripts. RESULTS: Retinal bipolar cells express both TRPM1 and Nova-1 proteins. In vitro addition of Nova-1 protein retards electrophoretic migration of TRPM1 RNA containing the ECA1 108,249,293 C > T SNP. Up-regulating Nova-1 expression in primary cultures of choroidal melanocytes carrying the intron 11 SNP caused an average log 2-fold reduction of ~6 (64-fold) of TRPM1 mRNA expression. CONCLUSIONS: These finding suggest that the equine TRPM1 SNP can act independently to reduce survival of TRPM1 mRNA escaping the intron 1 transcriptional stop signals in CSNB horses. Coexistence and co-inheritance of two independent TRPM1 mutations across 1000 equine generations suggests a selective advantage for the apparently deleterious CSNB trait.

Blindness in a wild American black bear cub (Ursus americanus).

An approximately six-month-old wild American black bear (Ursus americanus) was found wandering in Saskatchewan and was presented to the Veterinary Medical Centre of the Western College of Veterinary Medicine for apparent blindness. Clinical examination confirmed an inability to navigate a photopic maze, bilateral tapetal hyper-reflectivity, fundi devoid of retinal vessels, and small pale optic nerve papillae. Single-flash electroretinography revealed A and B-wave amplitudes of approximately 40 and 140 microvolts, respectively, in both eyes. Histologic abnormalities included bilateral optic papillary mineralization and bilateral segmental optic nerve degeneration, with occasional intralesional lymphocytes confirmed with immunohistochemistry for CD3+. There was also bilateral multifocal retinal dysplasia, gliosis, lymphocytic retinitis, a complete lack of retinal blood vessels, an intravitreal vascular membrane, and a mild lymphocytic-plasmacytic uveitis with small pre-iridal cellular membranes. The presence of a positive ERG in a blind bear with numerous retinal ganglion cells and degenerative changes in the optic nerve are most consistent with vision loss due to optic nerve injury, which given the young age of the bear likely occurred during ocular development. The presence of ocular inflammation suggests this injury resulted from an inflammatory/infectious process. The etiology could not be determined. Hepatic concentrations of vitamin A were within the normal reference range for domestic species. Pan-herpesvirus PCR and immunohistochemistry for canine distemper virus and Toxoplasma gondii were negative, although this does not rule out these or other infectious etiologies. This represents the first case report of neonatal or congenital ocular abnormalities in an ursid species.

Golden retriever cystic uveal disease: a longitudinal study of iridociliary cysts, pigmentary uveitis, and pigmentary/cystic glaucoma over a decade in western Canada.

OBJECTIVES: To determine the incidence of iridociliary cysts, pigmentary uveitis (PU)/pigmentary cystic glaucoma (PCG) in golden retriever dogs in western Canada, the progression of iridociliary cysts to PU/PCG, and a mode of inheritance for this disorder. ANIMAL STUDIED: A total of 830 golden retriever dogs from Alberta, Saskatchewan, and Manitoba from 2004 to 2014 were studied. PROCEDURE: Data were compiled from Canine Eye Registry Foundation (CERF) or Orthopedic Foundation for Animals (OFA) records (n = 630) and clinical consultations (n = 200) for a retrospective assessment of iridociliary cysts, PU, and PCG. RESULTS: Total incidence of iridociliary cysts and PU from CERF/OFA data were 4.8% (n = 30/630) and 5.9% (n = 37/630), respectively. Incidence of PU increased with ages >4 years (12.7%, n = 32/251). Dogs diagnosed with thin-walled, attached iridociliary cysts had a high risk of being diagnosed with PU or PCG upon re-examination (56.5%, n = 13/23). No dogs diagnosed with thick-walled, anterior chamber cysts (n = 7) developed PU or PCG within the time frame of the study. Data from clinical consultations confirmed that PU carried a poor prognosis for the affected eyes as 44.9% (n = 22/49) of dogs progressed to PCG. PU- and PCG-affected dogs followed a familial pattern and there was an association with thin-walled iridociliary cysts. Pedigree analysis suggested an autosomal dominant mode of inheritance with partial penetrance. CONCLUSIONS: Thin-walled iridociliary cysts are associated with PU and PCG. All breeding golden retriever dogs should be examined annually by an ophthalmologist. The incidence of this disorder is higher in western Canada than previous reports in North America.

Optic neuropathy in a herd of beef cattle in Alberta associated with consumption of moldy corn.

A group of beef cattle in eastern Alberta was investigated due to sudden onset of blindness after grazing on standing corn in mid-winter. Fumonisin-producing Fusarium spp. were isolated from the corn. Blindness was due to an optic nerve degeneration suspected to be secondary to fumonisin mycotoxin.

Neuropathie optique dans un cheptel de bovins de boucherie en Alberta associée à la consommation de maïs moisi. Un groupe de bovins de boucherie de l'est de l'Alberta a fait l'objet d'une enquête en raison de l'apparition soudaine de cécité après avoir brouté du maïs sur pied vers le milieu de l'hiver. Fusarium spp., qui produit la fumonisine, a été isolé dans le maïs. La cécité a été attribuable à la dégénération du nerf optique ayant pour cause suspectée la mycotoxine fumonisine.(Traduit par Isabelle Vallières).

Prevalence of pre-iridal monocellular and fibrovascular membranes in canine globes affected with congenital glaucoma associated with anterior segment dysgenesis, primary glaucoma associated with goniodysgenesis, and secondary glaucoma.

Objectives: The objectives of this study were to (i) evaluate the prevalence of pre-iridal monocellular and fibrovascular membranes in canine globes affected with congenital glaucoma associated with anterior segment dysgenesis (ASD), primary glaucoma associated with goniodysgenesis (GD), and secondary glaucoma, and (ii) examine the associations between monocellular and fibrovascular membranes by breed, gender, age and histopathologic ocular changes on light microscopic examination. Methods: Records of dogs who had eyes enucleated due to blindness and uncontrolled glaucoma were reviewed. Glaucoma was categorized clinically and histologically into three groups: congenital/ASD, primary/GD, and secondary glaucoma. The presence or absence and type of pre-iridal membrane (monocellular or fibrovascular) and other intraocular histologic findings were reviewed and compared statistically for each group. Results: In total, 108 canine globes (101 dogs) were included. Pre-iridal monocellular membranes were identified with light microscopy in 10 out of 19 congenital/ASD, 29 out of 40 primary, and 23 out of 49 secondary glaucoma globes. Fibrovascular membranes were observed in 3 out of 19 congenital/ASD, 9 out of 40 in primary, and 24 out of 49 secondary glaucoma globes. There were no associations between the type of membrane and breed, gender, or age. Peripheral anterior synechiae were more common in globes with fibrovascular membranes, and uveal atrophy was more common in globes with monocellular membranes. Conclusion: Pre-iridal monocellular membranes are common in all types of canine glaucoma. They are identified with light microscopy most easily in cases of primary glaucoma, and they are masked by pre-iridal fibrovascular membranes in other forms of glaucoma.

Optic chiasm B-cell lymphoma in a 20-month-old Mastiff dog.

A 20-month-old intact female Mastiff dog presented for evaluation of acute blindness. Computed tomography confirmed a tumor involved the optic chiasm and optic nerves. A B-cell lymphoma was confirmed with postmortem examinations. This case report documents a central nervous system neoplasm in a young dog.