Inheritance of cataracts and primary lens luxation in Jack Russell Terriers

OBJECTIVE: To characterize heritability and mode of inheritance of cataracts and primary lens luxation in Jack Russell Terriers. ANIMALS: 872 Jack Russell Terriers from which buccal epithelial cells were collected and phenotypes for cataracts and lens luxation were determined and an additional 1,898 Jack Russell Terriers without phenotypic information used to complete pedigree relationships and that were included in the analyses. PROCEDURES: Narrow-sense heritabilities and genetic correlation for cataracts and lens luxation were modeled by use of threshold analysis, whereas complex segregation analysis was used to characterize mode of inheritance. For the analyses, dogs < 6 years old, unless confirmed as having cataracts or lens luxation, were classified as an unknown phenotype. The possible involvement of an HSF4 mutation in cataracts was determined by DNA sequencing. RESULTS: Cataracts and primary lens luxation were highly heritable and genetically correlated, and neither was controlled by a single gene. Cataracts were not associated with an HSF4 mutation. CONCLUSIONS AND CLINICAL RELEVANCE: Analysis of the data indicated that concerted selection against both cataracts and primary lens luxation when choosing breeding animals can be used to improve ocular health in Jack Russell Terriers.     

Multiple molecular forms of inhibin in buffalo (Bubalus bubalis) ovarian follicular fluid

Inhibin is a heterodimeric glycoprotein hormone involved in the regulation of FSH release from the anterior pituitary gland and it has been characterized from various animals. Although, multiple molecular forms of inhibin have been reported from different species, however, the molecular nature of inhibin has not been studied in buffaloes. In the present study, attempts were made to identify inhibin in buffalo ovarian follicular fluid. Buffalo ovaries were obtained from the local abattoir and follicular fluid was aspirated from surface follicle (with diameter ?5 mm). A combination of techniques (viz., gel filtration, SDS-PAGE, Western blot etc.) was employed for identification and isolation of inhibin(s). Inhibin bands were detected at 129 and 63 kDa by Western blot analysis in non-reducing conditions. In reduced SDS-PAGE, 63 kDa fraction produced a single band while 129 kDa fraction resolved into four components of 63, 43, 29 and 20 kDa. Out of them only 29, 63 and the native 129 kDa fractions produced bands on Western blot analysis. In total five fractions (63, 54, 39, 29, 25 kDa) were obtained by trypsin digestion of 129 kDa form. However, only 63 and 29 kDa fractions showed immunoreactivity. In this study, for the first time, we have identified two major forms of inhibin (129 and 63 kDa) with little proteolytic cleavage/processing of the large precursor in the buffalo follicular fluid.     

Fear-related behaviour of dogs in veterinary practice

To investigate further the occurrence of fear-related behaviour in dogs in veterinary practice and to evaluate associated factors, 135 dogs were observed under practice conditions within the framework of a standardised test examination and the owners interviewed using a questionnaire. Most dogs exhibited fear reactions, particularly on the examination table, with 78.5% (106/135) categorised as ‘fearful’ based on their behaviour. Unlike weight and castration, age, gender and previous experience were significantly (P < 0.05) associated with fearful behaviour. Male dogs were significantly less ‘fearful’ than females and animals under <2 years were significantly less ‘fearful’ compared with older dogs. Those with only positive previous experiences in veterinary surgeries were significantly less ‘fearful’ than dogs that had a previous negative experience. Fear-related behaviour in veterinary practice is an issue of importance.     

Developmental programming: the role of growth hormone

Developmental programming of the fetus has consequences for physiologic responses in the offspring as an adult and, more recently, is implicated in the expression of altered phenotypes of future generations. Some phenotypes, such as fertility, bone strength, and adiposity are highly relevant to food animal production and in utero factors that impinge on those traits are vital to understand. A key systemic regulatory hormone is growth hormone (GH), which has a developmental role in virtually all tissues and organs. This review catalogs the impact of GH on tissue programming and how perturbations early in development influence GH function.     

IMAGING DIAGNOSIS ‐ SPONTANEOUS SUBPERIOSTEAL VERTEBRAL HEMORRHAGE IN A GREYHOUND

A 4‐year‐old, spayed female greyhound dog was presented with an acute onset of paraplegia. There was no known history of trauma or coagulopathy. Spinal cord compression was identified on MRI. Intra‐operative evaluation revealed the presence of a large subperiosteal hematoma and a smaller epidural hematoma. To the authors’ knowledge, this is the first report of a spinal subperiosteal hematoma diagnosed antemortem through MRI, with surgical exploration and successful treatment in a dog.     

Comparison of digital and optical hand-held refractometers for the measurement of feline urine specific gravity

Measuring urine specific gravity (USG) is an important component of urine analysis as it evaluates renal concentrating capability. The objective of this study was to quantify the difference in USG values between a hand-held optical analogue refractometer and a cat-specific digital instrument. Urine samples from 55 cats were assessed. There was a statistically significant difference between these two refractometers (P<0.001), with the optical refractometer (mean USG=1.031) consistently reading higher than the digital refractometer (mean USG=1.027). Results for a random subset of the samples (n=10) were compared with urine osmolality and both the optical and digital instruments demonstrated excellent correlation. While an accurate USG reading is important, it is unlikely that the statistical significance between the two instruments is clinically significant and, therefore, unlikely to result in a change in patient evaluation or treatment plans. While both the digital and optimal refractometers are highly correlated to the urine osmolality, making both devices valid for assessment of USG in clinical practice, this digital device is easier to read and eliminates the variability of subjective interpretation.     

LARYNGEAL ADENOCARCINOMA IN A DOG

Laryngeal adenocarcinoma was diagnosed in a 5-year-old golden retriever dog with no history of respiratory or pharyngeal difficulties. Radiographically the basihyoid bone was destroyed by the neoplasm, and extensive soft tissue mineralization ventral to the larynx was also present. Complete surgical resection was not possible due to diffuse involvement of the tongue and larynx. Cobalt-60 teletherapy was used for treatment of the tumor. There was no clinical evidence of tumor regrowth at approximately 12 months post treatment. This is an unusual example of primary laryngeal neoplasia due to the absence of clinical respiratory abnormalities and the aggressive destruction of the basihyoid bone.     

Oxidative stress in the pathogenesis of canine zinc‐responsive dermatosis

Zinc deficiency causes skin diseases both in humans and in animals. The underlying pathogenic mechanisms remain unclear, but a growing body of evidence indicates a role for zinc in skin protection against free radical‐induced oxidative damage. The immunohistochemical expression of heat shock proteins (HSPs; Hsp27, Hsp72, Hsp73 and Hsp90), Cu/Zn superoxide dismutase (SOD), metallothionein (MT), Ki‐67 antigen and active caspase‐3 were evaluated in normal canine skin and in samples from eight dogs with zinc‐responsive dermatosis. All investigated HSPs showed intense cytoplasmic immunostaining in the affected epidermis. Focal nuclear positivity of Hsp72 was also detected in keratinocytes. Although Cu/Zn SOD expression was similar to that observed in normal skin, MT immunoreactivity occurred in both the cytoplasm and the nucleus of basal cells in normal skin but was absent from the affected epidermis. Caspase‐3 activation was also absent in the involved epidermis, which revealed a high Ki‐67 index (a 3.5‐ to 9‐fold increase compared with normal skin). These results support the hypothesis that cellular response to stress, particularly oxidative stress, is involved in the pathogenesis of skin lesions in canine zinc‐responsive dermatosis. The lack of MT immunoreactivity in the affected epidermis may be indicative of low zinc levels, thus resulting in vulnerability to oxidative damage. In contrast, high expression levels of HSPs in skin during zinc deficiency may confer protection against a variety of dangerous stimuli, contributing to inhibition of apoptosis and to cell cycle regulation of proliferating keratinocytes.