Aberrant subcellular immunolocalization of NOTCH-1 activated intracellular domain in feline mammary tumours.

NOTCH-1 is a transmembrane receptor protein. Ligand proteins expressed on the surface of neighbouring cells bind to the NOTCH-1 extracellular domain by juxtacrine signalling and release the NOTCH intracellular domain (NICD) to alter gene expression. Forty feline mammary lesions (34 malignant and six hyperplastic) were submitted for immunohistochemical analysis of NICD expression using an anti-feline NICD monoclonal antibody. Associations between NICD expression in carcinomas and morphological parameters, as well as overall survival (OS), were investigated. NICD nuclear expression was observed in hyperplastic lesions (100%) while cytoplasmic localization was evident in carcinomas (0% nuclear positive; 87.5% cytoplasmic positive; 12.5% negative). Cytoplasmic NICD localization was statistically associated with carcinomas, while nuclear labelling was associated with hyperplasia. No significant correlation between positive or negative NICD expression and OS or morphological parameters was detected. NOTCH-1 activation, immunohistochemically identified by the NICD active form, appears to play a role in feline mammary carcinoma biology as the majority of tumours express this protein. Nuclear localization is consistent with the established NICD metabolic intranuclear pathway while cytoplasmic accumulation suggests aberrant NOTCH-1 signalling typical of malignant tumour progression.

Feline mammary carcinoma stem cells are tumorigenic, radioresistant, chemoresistant and defective in activation of the ATM/p53 DNA damage pathway.

Cancer stem cells were identified in a feline mammary carcinoma cell line by demonstrating expression of CD133 and utilising the tumour sphere assay. A population of cells was identified that had an invasive, mesenchymal phenotype, expressed markers of pluripotency and enhanced tumour formation in the NOD-SCID mouse and chick embryo models. This population of feline mammary carcinoma stem cells was resistant to chemotherapy and radiation, possibly due to aberrant activation of the ATM/p53 DNA damage pathway. Epithelial-mesenchymal transition was a feature of the invasive phenotype. These data demonstrate that cancer stem cells are a feature of mammary cancer in cats.

Breed, age and gender distribution of dogs with chronic hepatitis in the United Kingdom.

Standardised histological criteria are now available for the diagnosis of canine chronic hepatitis (CH). CH is common in dogs, but no studies have reported breed, age and gender distributions in the United Kingdom (UK). The objective of this study was to determine which breeds had an increased risk for developing CH in the UK and to report the age and gender distribution for those breeds. The databases of six veterinary histopathology laboratories were searched for cases with a histological diagnosis of CH according to standardised criteria. The breed, age and gender of dogs was recorded and compared to a control population to calculate the odds ratio and 95% confidence intervals for developing CH. A total of 551 cases of CH were identified, consisting of 61 breeds. Nineteen breeds were represented by five or more cases. Breeds with an increased risk for developing CH included the American cocker spaniel, Cairn terrier, Dalmatian, Dobermann pinscher, English cocker spaniel, English springer spaniel, Great Dane, Labrador retriever and Samoyed. The median age at diagnosis for all breeds with CH was 8 years (range 7 months to 16 years). Dalmatians, Dobermann pinschers and English springer spaniels with CH were significantly younger than Cairn terriers, English cocker spaniels and Labrador retrievers with CH. Females were over-represented when all cases were examined together. In conclusion, several breeds in the UK have an increased risk of CH, some of which have not been previously reported.

Severe necrotizing myocarditis caused by serratia marcescens infection in an axolotl (Ambystoma mexicanum).

This report provides the first account of the pathological changes associated with infection by Serratia marcescens in an adult male axolotl. The infection resulted in septicaemia with severe multifocal necrotizing myocarditis. The latter lesion evolved to cardiac rupture, haemopericardium and death resulting from cardiac tamponade. This animal was exposed to higher than usual temperatures (24-25 °C) 2 weeks before the onset of disease and this may have resulted in immunocompromise and opportunistic bacterial infection. S. marcescens was isolated from the coelomic and pericardial cavity. Both isolates were identical and were resistant to ß-lactam antibiotics, but not to aminoglycosides or fluoroquinolones. The production of red prodigiosin pigment by the bacterium suggested an environmental origin. Overall, the clinical and histopathological presentation suggests that S. marcescens should be included in the list of aetiological agents of the 'red-leg'/bacterial dermatosepticaemia syndrome of amphibians.

Arrhythmogenic right ventricular cardiomyopathy as a cause of unexpected cardiac death in two horses.

Postmortem and histological examination of the hearts from two horses, a five-year-old Clydesdale gelding and a 15-year-old cob gelding, revealed changes characteristic of arrhythmogenic right ventricular cardiomyopathy. In both cases, on gross examination, the right ventricular endocardium and interventricular septum were almost entirely replaced with a gelatinous yellow fibroareolar tissue. This tissue was histologically a combination of fibrous and adipose tissue that had replaced the normal myofibres and disrupted the Purkinje fibres.

Evaluation of suicide awareness programmes delivered to veterinary undergraduates and academic staff.

In an effort to increase suicide awareness skills among veterinary undergraduates, a three-hour suicide awareness workshop (safeTALK) was delivered to third-year Royal (Dick) School of Veterinary Studies undergraduates as part of their professional development curriculum. Students were able to opt out of the session by contacting the course organisers. A total of 26 of 151 (17 per cent) third-year students attended the workshop, and 17 completed a feedback questionnaire. The vast majority of the students reported that after completing the workshop they were more likely or much more likely to recognise the signs of a person at risk of suicide, approach a person at risk of suicide, ask a person about suicide, and connect a person at risk of suicide with help. Five veterinary academics attended a two-day Applied Suicide Intervention Skills Training (ASIST) course, and all reported that the course was effective in improving suicide awareness and intervention skills.

Effect of tissue processing on assessment of endoscopic intestinal biopsies in dogs and cats.

BACKGROUND: Prior studies failed to detect significant association between hypoalbuminemia and small intestinal lesions. HYPOTHESIS: Use of pictorial templates will enhance consistency of interpathologist interpretation and identification of intestinal lesions associated with hypoalbuminemia. ANIMALS: Tissues from 62 dogs and 25 cats examined as clinical cases at 7 referral veterinary practices in 4 countries. METHODS: Retrospective, observational study. Histopathology slides from sequential cases undergoing endoscopic biopsy were examined by 4 pathologists by pictorial templates. Changes for 9 microscopic features were recorded as normal, mild, moderate or severe, and 2- and 4-point scales were tested for consistency of interpretation. Logistic regression models determined odds ratios (OR) of histologic lesions being associated with hypoalbuminemia while kappa statistics determined agreement between pathologists on histologic lesions. RESULTS: There was poor agreement (kappa = -0.013 to 0.3) between pathologists, and institution of origin of slides had effect (kappa = 1.0 for 3 of 4 lesions on slides from Institution 5) on agreement between pathologists on selected histologic features. Using 2 point as opposed to 4-point grading scale increased agreement between pathologists (maximum kappa = 0.69 using 4-point scale versus maximum kappa = 1.0 using 2-point scale). Significant association (P = .019- .04; 95% OR = 3.14-10.84) between lacteal dilation and hypoalbuminemia was found by 3 pathologists. CONCLUSIONS AND CLINICAL IMPORTANCE: Substantial inconsistency between pathologists remains despite use of pictorial template because of differences in slide processing. Distinguishing between mild and moderate lesions might be important source of the disagreement among pathologists.

Effect of sample quality on the sensitivity of endoscopic biopsy for detecting gastric and duodenal lesions in dogs and cats.

BACKGROUND: The quality of histopathology slides of endoscopic biopsies from different laboratories varies, but the effect of biopsy quality on outcome is unknown. HYPOTHESIS: The ability to demonstrate a histologic lesion in the stomach or duodenum of a dog or cat is affected by the quality of endoscopic biopsy samples submitted. More endoscopic samples are needed to find a lesion in poor-quality tissue specimens. ANIMALS: Tissues from 99 dogs and 51 cats were examined as clinical cases at 8 veterinary institutions or practices in 5 countries. METHODS: Histopathology slides from sequential cases that underwent endoscopic biopsy were submitted by participating institutions. Quality of the histologic section of tissue (inadequate, marginal, adequate), type of lesion (lymphangiectasia, crypt lesion, villus blunting, cellular infiltrate), and severity of lesion (normal, mild, moderate, severe) were determined. Sensitivity of different quality tissue samples for finding different lesions was determined. RESULTS: Fewer samples were required from dogs for diagnosis as the quality of the sample improved from inadequate to marginal to adequate. Duodenal lesions in cats displayed the same trend except for moderate duodenal infiltrates for which quality of tissue sample made no difference. Gastric lesions in dogs and mild gastric lesions in cats had the same trend, whereas the number of tissue samples needed to diagnose moderately severe gastric lesions in cats was not affected by the quality of tissue sample. CONCLUSIONS AND CLINICAL IMPORTANCE: The quality of endoscopically obtained tissue samples has a profound effect on their sensitivity for identifying certain lesions, and there are differences between biopsies of canine and feline tissues.

Dynamic measurement of intraocular pressure using a mechanical model of the human eye.

Heightened intraocular pressure (IOP) is not always indicative of glaucoma, but is an important risk factor for the progression of certain types of eye damage not obviously felt by the sufferer. A number of measurement systems have been devised in the past to measure the IOP by applying force or pressure to the cornea, but past studies have shown that the cornea thickness and its curvature have a significant effect on measurements which may ultimately lead to clinical misdiagnosis. A cyclic strain controlled dynamic probing measurement system has been developed using an indenter of diameter 3.06 mm operating at actuation frequencies of between 0.1 Hz and 4 Hz and displacements up to 1 mm. The cyclic strain is actuated by a linear stage with a load cell and indenter coupled in series. The load cell records the resultant cyclic force where the dynamic modulus is expressed as amplitude ratio and phase lag. The mechanical eye model consists of a silicone membrane that can be varied in thickness and it is distended hydraulically to simulate a range of IOP. A pressure sensor measures the dynamic IOP within the system which will be compared against the dynamic modulus. The relationship between the mechanical properties and the physical properties of the membrane will be established in order to develop a probe which can be used clinically taking into account the effects of corneal stiffness and hydraulic behaviour of the eye. The preliminary study reported here a significant increase in amplitude ratio and mean ratio with increasing the frequency similar to the behaviour found in biological materials and gelatin.

Micro-engineered remote palpation device for assessing tissue compliance.

This paper concerns the operation of the actuator for a prototype micro-engineered mechanical palpation device for deployment via a cystoscope to measure the dynamic mechanical properties of the prostate gland in vivo. The subassembly consists of a 400x200 microm silicon (Si) piston manufactured using deep reactive ion etching (DRIE) housed within an anodically bonded glass-Si-glass sandwiched housing. The micro-channel on the Si layer was formed by powder blasting and contains the micro-piston with one end pointing to the side of the housing and the other facing a via hole leading to a capillary tube. The opening on the side of the housing was sealed by a 5 microm thick silicone membrane which acts to retain the micro-piston and act as a return spring. A 320 microm diameter capillary forms the connection between the micro-channel and a micro-syringe which is operated by a programmable syringe pump to produce a reciprocating action. A pressure sensor is connected along the capillary tube to measure the dynamic pressure within the system. The micro-piston has already been used, separately actuated to measure the dynamic mechanical properties of known viscoelastic materials and prostate tissue. The purpose of the present work is to assess the functionality of the actuator assembly.

Assessing the quality of biological tissues using structure-property relationships: macro-scale tests on engineered phantoms.

The overall aim of this work is to determine the quality of biological tissues based on the relationship between the dynamic mechanical properties and their histology. Two sets of rigs have been developed for dynamic mechanical measurement, one for micro-scale testing and the other for macro-scale testing. Preliminary results using the macro-scale measurement system only are reported here. This system uses strain-controlled cyclic probing actuated by a linear stepper motor operating at actuation frequencies between 0.5Hz and 20Hz. A 1mm diameter indenter probes the specimen up to a displacement of 0.2mm and a load cell measures the resultant cyclic force. A series of tissue mimics were prepared using various formulations of gelatin and safflower oil and preliminary tests carried out to determine a suitable range of experimental variables and to establish the repeatability of the tests. The dynamic mechanical properties are expressed as amplitude ratio, phase difference and mean ratios of stress and strain, and the behaviour of these measurands with actuation frequency, mean strain and strain amplitude was observed. Results consistent with the literature were found which form a foundation for measurements on collagen-lipid biological tissues.

Foot pad dermatitis in growing turkeys is associated with cytokine and cellular changes indicative of an inflammatory immune response.

Cell and cytokine responses during the development of foot pad dermatitis (FPD) in growing turkeys were studied in a model system. The objective was to evaluate the hypothesis that FPD is an allergic response to the environmental materials. Hybrid female turkeys at 28 days of age were exposed to wet litter for 48 h in a randomized block experiment. Expression levels of pro-inflammatory (interleukin (IL)-1 beta, IL-6, and CXCLi2) and signature Th1 (interferon-gamma), Th2 (IL-13) and Treg (IL-10) cytokines were measured in the foot pad tissues using real-time quantitative reverse transcriptase-polymerase chain reaction. Sections of foot pad tissue were stained for CD4+ and CD8+ T lymphocytes, B lymphocytes and macrophages using antibodies that specifically recognize the relevant cell types in the turkey. In the footpads of birds suffering from FPD, there were large fold increases in mRNA expression levels for the pro-inflammatory cytokines IL-1 beta (+635), IL-6 (+65), and CXCLi2 (+1924), and interferon-gamma (+32), whereas there was only a small increase in IL-13 mRNA (+2) and no change in IL-10 mRNA expression levels. CD4+ and CD8+ T lymphocytes were present in the footpads of more than 90% of birds housed on wet litter compared with 25% or less on dry litter. Macrophages were observed in the footpads of approximately 85% of birds housed on wet litter compared with none in birds housed on dry litter. B lymphocytes were not detected in tissue from any of the birds. The data suggest that FPD is associated with a rapidly occurring inflammatory response, rather than a Th2-mediated allergic reaction.

Third degree atrioventricular block and accelerated idioventricular rhythm associated with a heart base chemodectoma in a syncopal Rottweiler.

A 7-year-old male intact Rottweiler was presented with a 1-week history of lethargy, anorexia, vomiting and multiple syncopal events. The results of the clinical examination and electrocardiography were consistent with a third degree atrioventricular block and an intermittent accelerated idioventricular rhythm. Haematology, serum biochemistry, serology for Borrelia burgdorferi, blood culture, total T4, thoracic radiography and echocardiography did not reveal the cause of the arrhythmia. Response to medical treatment with isoproterenol was poor. Pacemaker placement was declined by the owners and the dog was euthanized at their request. Histopathological examination of the heart revealed a chemodectoma at the base of the heart. There was no neoplastic infiltration of the conduction tissue. Potential mechanisms explaining the association of the arrhythmias and the tumour, such as vagal stimulation and neuroendocrine factors are discussed.

High litter moisture alone is sufficient to cause footpad dermatitis in growing turkeys.

1. Four randomised block experiments were conducted to determine the role of litter moisture, excreta and alternative bedding materials on the development of footpad dermatitis in growing turkeys. 2. Adding water to the litter increased external and histopathological scores independently of the presence of excreta. Fully developed lesions were induced by the application of water to dry litter in 2 to 4 d. 3. Footpad lesions were associated with discomfort during walking in one experiment and body weight was lower in birds on wet compared with dry litter. 4. Footpad lesions had virtually healed 15 d after transfer of the turkeys from wet to dry litter although histopathology assessment showed some residual tissue repair. 5. Long barley straw was associated with high footpad scores on wet and dry treatments. The footpad scores for turkeys on reprocessed cardboard chips were similarly high whereas scores were similar on paper litter and wood shavings whether dry or wet. 6. It was concluded that high litter moisture alone was sufficient to cause footpad dermatitis in young turkeys and that footpad dermatitis should be minimised by the maintenance of dry litter.

Evaluation of disease activity markers in dogs with idiopathic inflammatory bowel disease.

OBJECTIVES: To evaluate the clinical utility of serum tumour necrosis factor-alpha, C-reactive protein and microalbuminuria as disease activity markers in canine idiopathic inflammatory bowel disease. METHODS: Dogs with chronic gastrointestinal disease for which no underlying cause could be identified were considered to have idiopathic inflammatory bowel disease and were included in the study. Serum tumour necrosis factor-alpha was assessed using a canine-specific ELISA, C-reactive protein by immunoturbidometric assay and quantitative microalbuminuria was analysed using a monoclonal antibody directed against canine albumin. The canine inflammatory bowel disease activity index and histopathologic grade were used to assess disease severity; biologic markers were then compared with the canine inflammatory bowel disease activity index and histopathologic grade. RESULTS: Sixteen dogs were included in the study. C-reactive protein level was mildly elevated in 15 dogs. Microalbuminuria was elevated in two of 15 dogs, and tumour necrosis factor-alpha was not detected in any dog tested. No correlation was found between the canine inflammatory bowel disease activity index and C-reactive protein or microalbuminuria or between histopathologic grade and C-reactive protein or microalbuminuria. There was no correlation between histopathologic grade and the canine inflammatory bowel disease activity index. CLINICAL SIGNIFICANCE: Although only a small number of dogs were evaluated, this study does not support the use of serum tumour necrosis factor-alpha measured by canine-specific ELISA or microalbuminuria in the evaluation of disease activity in dogs with idiopathic inflammatory bowel disease. Although mildly elevated in most dogs, C-reactive protein did not reflect disease severity as assessed by the canine inflammatory bowel disease activity index or histopathologic grade.

High dietary concentrations of biotin did not prevent foot pad dermatitis in growing turkeys and external scores were poor indicators of histopathological lesions.

1. A randomised block experiment was conducted to determine the effects of increasing dietary biotin supplementation (0, 200, 800 and 1600 microg/kg) on macroscopic and histological changes associated with the development of foot pad dermatitis (FPD) in growing turkeys. 2. Each treatment was replicated in 4 pens containing 36 birds at the start of the experiment. The birds were weighed and external foot pads were scored at 2-week intervals from 2 to 14 weeks of age. A blood sample was obtained at the same ages from two birds in each pen and tissue from one foot pad was processed for histological examination. Liver samples were obtained for determination of fat content. 3. Increasing dietary biotin supplementation was associated with higher initial plasma concentrations of biotin but there was no effect on external scores or histopathology of foot pad lesions. FPD increased rapidly from 2 to 6 weeks and remained similar thereafter. There was no effect of dietary biotin on liver fat content. 4. The correlations between external foot pad scores at different ages were all less than 0.4. The correlation between external and histopathological scores was 0.56 and the respective correlations with body weight were 0.52 and 0.65. There were no differences between the body weights of birds with different external scores but high histopathological scores were associated with lower body weights. 5. It was concluded that current recommendations for biotin in wheat-soy rations for growing turkeys are adequate for normal growth and development and that higher supplements of biotin in these experimental conditions did not prevent the occurrence of FPD.

Multi-scale techniques of measuring the dynamic properties of biological tissues.

The overall aim of this study is to establish relationships between the histology of biological tissues and their mechanical properties, especially their dynamic modulus. The emphasis is on the physical scale of the probe used in relation to the size of the histological features in the material of interest. The selection of a model system (connective tissue) is described along with a corresponding gelatin-based system in which the make-up of the material can be "engineered" reproducibly. Next three experimental rigs are described with regard to their suitability for making measurements at a variety of scales; the micro-scale, the meso-scale and the macro-scale. Finally, some preliminary measurements on the micro-scale rig are presented and preliminary conclusions drawn on the methodology.