Melanoma of the Choroid in a Dog

Intraocular tumors are rare in the dog. Of the reported neoplasms, melanomas are the most common. These tumors characteristically arise in the anterior uvea and secondarily infiltrate posteriorly into the choroid and/or anteriorly into the corneoscleral region. Advanced tumors may extend extraocularly. In the dog, isolated choroidal melanomas are extremely uncommon; to the authors\u27 knowledge, only two cases have been previously reported. This report describes a pigmented choroidal tumor in a dog with clinical and histopathologic features resembling a benign melanoma

Multiple congenital ocular anomalies in Icelandic horses

<p>Abstract</p> <p>Background</p> <p>Multiple congenital ocular anomalies (MCOA) syndrome is a hereditary congenital eye defect that was first described in Silver colored Rocky Mountain horses. The mutation causing this disease is located within a defined chromosomal interval, which also contains the gene and mutation that is associated with the Silver coat color (<it>PMEL17</it>, exon 11). Horses that are homozygous for the disease-causing allele have multiple defects (MCOA-phenotype), whilst the heterozygous horses predominantly have cysts of the iris, ciliary body or retina (Cyst-phenotype). It has been argued that these ocular defects are caused by a recent mutation that is restricted to horses that are related to the Rocky Mountain Horse breed. For that reason we have examined another horse breed, the Icelandic horse, which is historically quite divergent from Rocky Mountain horses.</p> <p>Results</p> <p>We examined 24 Icelandic horses and established that the MCOA syndrome is present in this breed. Four of these horses were categorised as having the MCOA-phenotype and were genotyped as being homozygous for the <it>PMEL17 </it>mutation. The most common clinical signs included megaloglobus, iris stromal hypoplasia, abnormal pectinate ligaments, iridociliary cysts occasionally extending into the peripheral retina and cataracts. The cysts and pectinate ligament abnormalities were observed in the temporal quadrant of the eyes. Fourteen horses were heterozygous for the <it>PMEL17 </it>mutation and were characterized as having the Cyst-phenotype with cysts and occasionally curvilinear streaks in the peripheral retina. Three additional horses were genotyped as <it>PMEL17 </it>heterozygotes, but in these horses we were unable to detect cysts or other forms of anomalies.</p> <p>One eye of a severely vision-impaired 18 month-old stallion, homozygous for the <it>PMEL17 </it>mutation was examined by light microscopy. Redundant duplication of non-pigmented ciliary body epithelium, sometimes forming cysts bulging into the posterior chamber and localized areas of atrophy in the peripheral retina were seen.</p> <p>Conclusions</p> <p>The MCOA syndrome is segregating with the <it>PMEL17 </it>mutation in the Icelandic Horse population. This needs to be taken into consideration in breeding decisions and highlights the fact that MCOA syndrome is present in a breed that are more ancient and not closely related to the Rocky Mountain Horse breed.</p

Post-traumatic ocular lymphoma in three rabbits (Oryctolagus cuniculus)

This report describes post-traumatic ocular lymphoma in 3 companion rabbits; 2 rabbits with unilateral disease and 1 with bilateral disease. Historical findings suggestive of a traumatic event included either external unilateral ocular trauma or bilateral phacoemulsification. Severe corneal changes, presence of an anterior chamber mass(es), low intraocular pressures, and ocular discomfort were noted on ophthalmic examinations. All eyes were treated for variable courses with standard ophthalmic topical medications (antibiotic, anti-inflammatories, and steroid) and systemic anti-inflammatories. Based upon progression of disease, all affected eyes were ultimately enucleated; lenticular capsular rupture and a round cell neoplasm effacing normal structures with variable mitotic indices were noted on histopathology. Neoplastic lymphocytes strongly expressed CD79a via immunohistochemistry and lacked expression for CD3, indicating B lymphocyte lineage and not of T cell lineage. A single animal had evidence of local metastasis to a regional lymph node. Post-traumatic sarcomas have been reported in this species previously, however, these cases are the first reports of this novel round cell variant, named post-traumatic ocular lymphoma due to the B cell lineage confirmed through immunohistochemistry. Clinicians should be aware of this clinical presentation and the possibility of metastasis when evaluating ocular pathology in this species. Copyright 2018 Elsevier Inc. All rights reserved

The PPCD1 Mouse: Characterization of a Mouse Model for Posterior Polymorphous Corneal Dystrophy and Identification of a Candidate Gene

The PPCD1 mouse, a spontaneous mutant that arose in our mouse colony, is characterized by an enlarged anterior chamber resulting from metaplasia of the corneal endothelium and blockage of the iridocorneal angle by epithelialized corneal endothelial cells. The presence of stratified multilayered corneal endothelial cells with abnormal patterns of cytokeratin expression are remarkably similar to those observed in human posterior polymorphous corneal dystrophy (PPCD) and the sporadic condition, iridocorneal endothelial syndrome. Affected eyes exhibit epithelialized corneal endothelial cells, with inappropriate cytokeratin expression and proliferation over the iridocorneal angle and posterior cornea. We have termed this the “mouse PPCD1” phenotype and mapped the mouse locus for this phenotype, designated “Ppcd1”, to a 6.1 Mbp interval on Chromosome 2, which is syntenic to the human Chromosome 20 PPCD1 interval. Inheritance of the mouse PPCD1 phenotype is autosomal dominant, with complete penetrance on the sensitive DBA/2J background and decreased penetrance on the C57BL/6J background. Comparative genome hybridization has identified a hemizygous 78 Kbp duplication in the mapped interval. The endpoints of the duplication are located in positions that disrupt the genes Csrp2bp and 6330439K17Rik and lead to duplication of the pseudogene LOC100043552. Quantitative reverse transcriptase-PCR indicates that expression levels of Csrp2bp and 6330439K17Rik are decreased in eyes of PPCD1 mice. Based on the observations of decreased gene expression levels, association with ZEB1-related pathways, and the report of corneal opacities in Csrp2bptm1a(KOMP)Wtsi heterozygotes and embryonic lethality in nulls, we postulate that duplication of the 78 Kbp segment leading to haploinsufficiency of Csrp2bp is responsible for the mouse PPCD1 phenotype. Similarly, CSRP2BP haploinsufficiency may lead to human PPCD

Viral Replication Rate Regulates Clinical Outcome and CD8 T Cell Responses during Highly Pathogenic H5N1 Influenza Virus Infection in Mice

Since the first recorded infection of humans with H5N1 viruses of avian origin in 1997, sporadic human infections continue to occur with a staggering mortality rate of >60%. Although sustained human-to-human transmission has not occurred yet, there is a growing concern that these H5N1 viruses might acquire this trait and raise the specter of a pandemic. Despite progress in deciphering viral determinants of pathogenicity, we still lack crucial information on virus/immune system interactions pertaining to severe disease and high mortality associated with human H5N1 influenza virus infections. Using two human isolates of H5N1 viruses that differ in their pathogenicity in mice, we have defined mechanistic links among the rate of viral replication, mortality, CD8 T cell responses, and immunopathology. The extreme pathogenicity of H5N1 viruses was directly linked to the ability of the virus to replicate rapidly, and swiftly attain high steady-state titers in the lungs within 48 hours after infection. The remarkably high replication rate of the highly pathogenic H5N1 virus did not prevent the induction of IFN-β or activation of CD8 T cells, but the CD8 T cell response was ineffective in controlling viral replication in the lungs and CD8 T cell deficiency did not affect viral titers or mortality. Additionally, BIM deficiency ameliorated lung pathology and inhibited T cell apoptosis without affecting survival of mice. Therefore, rapidly replicating, highly lethal H5N1 viruses could simply outpace and overwhelm the adaptive immune responses, and kill the host by direct cytopathic effects. However, therapeutic suppression of early viral replication and the associated enhancement of CD8 T cell responses improved the survival of mice following a lethal H5N1 infection. These findings suggest that suppression of early H5N1 virus replication is key to the programming of an effective host response, which has implications in treatment of this infection in humans

Presumed solitary intraocular or conjunctival lymphoma in dogs and cats: 9 cases (1985-2013).

ObjectiveTo determine prevalence, reason for evaluation, treatment, and outcome for dogs and cats with presumed solitary ocular lymphoma (PSOL).DesignRetrospective case series.Animals7 dogs and 2 cats with PSOL.ProceduresMedical records were reviewed. Progression-free survival time (PFST) and overall survival time (OST) were determined.ResultsAnimals with intraocular (4 dogs and 1 cat) or conjunctival (3 dogs and 1 cat) lymphoma represented 0.1% and 0.08% of patients with lymphoma evaluated at the hospital during the study period, respectively. Animals with intraocular lymphoma represented 0.19% of all patients with uveitis; animals with conjunctival lymphoma represented 0.16% of all patients with conjunctivitis. Tumors included B-cell (2 intraocular and 1 conjunctival), non-B-cell, non-T-cell (1 intraocular), and T-cell (3 conjunctival) neoplasms; immunophenotype of 2 uveal lymphomas was not determined. Treatments included enucleation (4 intraocular) and chemotherapy (3 intraocular and 2 conjunctival). All dogs with intraocular lymphoma developed neurologic signs. Lymph node metastasis was detected in 2 patients with conjunctival lymphoma. Median PFST and OST were 178 days for all animals with PSOL, dogs with PSOL, and animals with intraocular lymphoma. Median PFST and OST for animals with conjunctival lymphoma were 221 and 549 days, respectively.Conclusions and clinical relevanceResults indicated PSOL was uncommon, but should be considered a differential diagnosis for animals with uveitis or conjunctivitis. Performance of MRI and cytologic analysis of CSF and regional lymph node aspirate samples may be beneficial for such patients. Prognosis seemed to be better for animals with conjunctival lymphoma than it was for those with intraocular lymphoma

Presumed solitary intraocular or conjunctival lymphoma in dogs and cats: 9 cases (1985-2013).

ObjectiveTo determine prevalence, reason for evaluation, treatment, and outcome for dogs and cats with presumed solitary ocular lymphoma (PSOL).DesignRetrospective case series.Animals7 dogs and 2 cats with PSOL.ProceduresMedical records were reviewed. Progression-free survival time (PFST) and overall survival time (OST) were determined.ResultsAnimals with intraocular (4 dogs and 1 cat) or conjunctival (3 dogs and 1 cat) lymphoma represented 0.1% and 0.08% of patients with lymphoma evaluated at the hospital during the study period, respectively. Animals with intraocular lymphoma represented 0.19% of all patients with uveitis; animals with conjunctival lymphoma represented 0.16% of all patients with conjunctivitis. Tumors included B-cell (2 intraocular and 1 conjunctival), non-B-cell, non-T-cell (1 intraocular), and T-cell (3 conjunctival) neoplasms; immunophenotype of 2 uveal lymphomas was not determined. Treatments included enucleation (4 intraocular) and chemotherapy (3 intraocular and 2 conjunctival). All dogs with intraocular lymphoma developed neurologic signs. Lymph node metastasis was detected in 2 patients with conjunctival lymphoma. Median PFST and OST were 178 days for all animals with PSOL, dogs with PSOL, and animals with intraocular lymphoma. Median PFST and OST for animals with conjunctival lymphoma were 221 and 549 days, respectively.Conclusions and clinical relevanceResults indicated PSOL was uncommon, but should be considered a differential diagnosis for animals with uveitis or conjunctivitis. Performance of MRI and cytologic analysis of CSF and regional lymph node aspirate samples may be beneficial for such patients. Prognosis seemed to be better for animals with conjunctival lymphoma than it was for those with intraocular lymphoma