Jane Sansom

Epidemiological study of blood pressure in domestic cats

Blood pressure was measured indirectly in 203 cats using an oscillometric technique in conjunction with a tail cuff. Systolic blood pressure was found to be log normally distributed across the population, while diastolic pressure was log log normally distributed. Blood pressure was found to rise with age (systolic, diastolic, mean arterial and pulse pressure were significantly higher in animals aged 11 years or over than in animals aged under 11 years) but this rise did not parallel an increase in plasma urea or creatinine. Cats with clinical renal disease did however have higher blood pressures than normal cats, as did cats with ocular change consistent with hypertensive retinopathy.

Keratomycosis in six horses in the United Kingdom.

Six horses with keratomycosis were examined and three different clinical expressions of the disease were recognised. The diagnostic work-up and response to treatment is described.

Expression of cyclooxygenase-2 by equine ocular and adnexal squamous cell carcinomas

OBJECTIVE To investigate whether cyclooxygenase-2 (COX-2) is expressed by equine ocular and adnexal squamous cell carcinomas (SCC). METHODS Forty-three samples of histologically confirmed cases of ocular SCC or carcinoma in situ (CIS) from 34 horses presented to the Animal Health Trust between 1992 and 2004 were subjected to a standard, two-layered, indirect immunohistochemical method using a rabbit polyclonal antihuman COX-2 antibody. Ten formalin-fixed, paraffin-embedded tissue samples taken from recognized predilection sites for SCC, from the grossly normal eyes of 10 horses euthanized for reasons unrelated to this study, were used as negative controls. Samples of equine fetal kidney were used as positive controls. Following immunolabeling, the number of normal and neoplastic epithelial cells exhibiting positive COX-2 expression was recorded along with staining intensity and distribution. RESULTS Of 43 tumors, 34 were defined as first presentation tumors. When compared with control tissue, in which 0% (0/10) of samples expressed COX-2, significantly more of these samples with SCC (58.6%, 17/29: P = 0.002), CIS (60%, 3/5: P = 0.022) or either tumor type (58.8%, 20/34: P = 0.001) exhibited positive cytoplasmic and perinuclear immunohistochemical staining for COX-2. Of the samples exhibiting positive immunohistochemical staining, only 10% (2/20) showed staining in 2%-10% of neoplastic cells, while 90% (18/20) showed staining in 1% of neoplastic cells. About 70% (14/20) of those positively immunolabeled samples exhibited an intensity of staining greater than or equal to the staining exhibited by the equine fetal kidney positive control. CONCLUSION Neoplastic tissue from both equine ocular SCC and CIS exhibit COX-2 expression at significantly higher levels than normal control ocular tissue. However, the percentage of cells expressing positive immunohistochemical staining is consistently low. On the basis of this study, it is unlikely that anti-COX-2 therapy would be of benefit in the treatment of equine ocular and adnexal SCC.

Eosinophilic fibrosing gastritis and toxoplasmosis in a cat

A 3-year-old, neutered male Tiffany cat was presented to the Animal Health Trust for investigation of pyrexia and a gastric lesion. Radiography and ultrasound showed severe thickening of the gastric wall and regional lymphadenopathy. There was altered gastric wall layering, predominately due to muscularis thickening. Histopathology confirmed eosinophilic fibrosing gastritis. The cat also had evidence of generalised Toxoplasma gondii infection, which may have been responsible for the gastric changes.

Calcareous degeneration of the canine cornea.

The purpose of this paper is to describe a specific presentation of canine corneal calcification. Fourteen cases are described. In seven cases the corneal lesions were bilaterally symmetrical. In five cases the corneal lesion was unilateral. Two dogs were uniocular, the contralateral eye had been enucleated between 1 and 3 months previously by the referring veterinary surgeon following corneal ulceration and perforation. Of a total of 21 eyes with corneal calcification, 16 eyes had associated ulceration. The ulceration presented as follows: two eyes had descemetocoeles, four eyes had corneal perforations, eight eyes had stromal ulceration, and two eyes had superficial punctate ulceration. The cause of the corneal mineralization remains undetermined but underlying systemic disease, particularly hyperadrenocorticism (Cushings Syndrome), is suspected as a possible contributing factor in some of these cases. Histopathology was carried out on three cases following a keratectomy and placement of a conjunctival pedicle flap into the ulcerated lesion.

Corneal squamous cell carcinoma in a Border Collie

A 6-year-old, female, spayed Border Collie was presented to the Unit of Comparative Ophthalmology at the Animal Health Trust with a 6-month history of a progressive nonpainful opacity of the left cornea. A keratectomy was performed and the tissue submitted for histopathology. The diagnosis was squamous cell carcinoma. There has been no recurrence of the neoplasm to date (5 months). Canine corneal squamous cell carcinoma (SCC) has not been reported previously in the UK.

Canine dacryolithiasis: a case description and mineral analysis.

A 4-year-old, female, spayed, Labrador retriever was presented with a painless swelling of the left ventromedial eyelid and epiphora of 3 months duration. Bilateral patency of the nasolacrimal system was confirmed by the appearance of fluorescein dye at both nares. Ultrasonography revealed a well-demarcated fluid-filled structure containing echogenic ill-defined material in close proximity to the nasolacrimal system. A transconjunctival surgical approach confirmed the close anatomical proximity of the cyst and the absence of a communication with the inferior canaliculus. The cyst contained multiple intraluminal calculi (dacryoliths). Following surgical excision of the cyst, the epiphora resolved and no recurrence was noted over a 12-month follow-up period. On histopathology, the cystic structure was lined by stratified squamous epithelium, consistent with lacrimal canaliculus epithelium. Presumed progression of a canalicular diverticulum to a cyst with the formation of intraluminal dacryoliths was suspected. Mineral analysis of the dacryoliths revealed a calcium carbonate composition.

An intronic LINE-1 insertion in MERTK is strongly associated with retinopathy in Swedish Vallhund dogs

The domestic dog segregates a significant number of inherited progressive retinal diseases, several of which mirror human retinal diseases and which are collectively termed progressive retinal atrophy (PRA). In 2014, a novel form of PRA was reported in the Swedish Vallhund breed, and the disease was mapped to canine chromosome 17. The causal mutation was not identified, but expression analyses of the retinas of affected Vallhunds demonstrated a 6-fold increased expression of the MERTK gene compared to unaffected dogs. Using 24 retinopathy cases and 97 controls with no clinical signs of retinopathy, we replicated the chromosome 17 association in Swedish Vallhunds from the UK and aimed to elucidate the causal variant underlying this association using whole genome sequencing (WGS) of an affected dog. This revealed a 6–8 kb insertion in intron 1 of MERTK that was not present in WGS of 49 dogs of other breeds. Sequencing and BLASTN analysis of the inserted segment was consistent with the insertion comprising a full-length intact LINE-1 retroelement. Testing of the LINE-1 insertion for association with retinopathy in the UK set of 24 cases and 97 controls revealed a strong statistical association (P-value 6.0 x 10−11) that was subsequently replicated in the original Finnish study set (49 cases and 89 controls (P-value 4.3 x 10−19). In a pooled analysis of both studies (73 cases and 186 controls), the LINE-1 insertion was associated with a ~20-fold increased risk of retinopathy (odds ratio 23.41, 95% confidence intervals 10.99–49.86, P-value 1.3 x 10−27). Our study adds further support for regulatory disruption of MERTK in Swedish Vallhund retinopathy; however, further work is required to establish a functional overexpression model. Future work to characterise the mechanism by which this intronic mutation disrupts gene regulation will further improve the understanding of MERTK biology and its role in retinal function.

Penetrating ocular gunshot injury in a Labrador Retriever

A 3½-year-old, female (spayed) working black Labrador Retriever was referred to the Unit of Comparative Ophthalmology at the Animal Health Trust after a penetrating lead gunshot injury to the right eye. Clinical examination revealed penetrating injuries to the right cornea, left lateral canthus, and left forelimb. Radiography revealed the presence of multiple metallic foreign bodies in the head and one in the left forelimb. B-mode ocular ultrasonography confirmed the presence of an intraocular metallic foreign body within the posterior tunics of the right eye. Medical treatment of the right eye over a period of 1 month resulted in a comfortable, visual eye. Long-term follow-up over 4½ years revealed a slow deterioration in vision because of progressive lens opacification and the presence of a localized area of chorioretinopathy.