P.S. Yam

An epidemiological study of environmental factors associated with canine obesity.

OBJECTIVES To assess the relationships between socioeconomic and other environmental factors with canine obesity. METHODS This was a cross-sectional questionnaire study of dog owners attending five primary veterinary practices in the UK. Owners were asked about dog age, neuter status, feeding habits, dog exercise, household income and owner age. The body condition score of the dogs was also assessed. Factors hypothesised to be associated with obesity were investigated. RESULTS In total, data from 696 questionnaires were evaluated. Out of those data evaluated, 35.3% of dogs (n=246) were classed as an ideal body shape, 38.9% (n=271) were overweight, 20.4% (n=142) were obese and 5.3% (n=37) were underweight. Identified risk factors associated with obesity included owner age, hours of weekly exercise, frequency of snacks/treats and personal income. CLINICAL SIGNIFICANCE Environmental risk factors associated with canine obesity are multifactorial and include personal income, owner age, frequency of snacks/treats and amount of exercise the dog receives. Awareness about health risks associated with obesity in dogs is significantly less in people in lower income brackets. This phenomenon is recognised in human obesity.

Drug development for stroke : importance of protecting cerebral white matter

Multiple pharmacological mechanisms have been identified over the last decade which can protect grey matter from ischaemic damage in experimental models. A large number of drugs targeted at neurotransmitter receptors and related mechanisms involved in ischaemic damage have advanced to clinical trials in stroke and head injury based on their proven ability to reduce grey matter damage in animal models. The outcome to date of the clinical trials of neuroprotective drugs has been disappointing. Although the failure to translate preclinical pharmacological insight into therapy is multifactorial, we propose that the failure to ameliorate ischaemic damage to white matter has been a major factor. The recent development of quantitative techniques to assess ischaemic damage to cellular elements in white matter, both axons and oligodendrocytes, allows rigorous evaluation of pharmacologic mechanisms which may protect white matter in ischaemia. Such pharmacological approaches provide therapeutic opportunities which are both additional or alternatives to those currently being evaluated in man.

Amyloid precursor protein accumulates in white matter at the margin of a focal ischaemic lesion

Amyloid precursor protein (APP) is transported by fast anterograde axonal transport. Since disruption of this transport results in APP accumulation, APP has been proposed as a sensitive marker of axonal injury. In the present study, axonal injury in subcortical white matter and myelinated fibre tracts permeating the striatum, 24 h after permanent middle cerebral artery occlusion in the rat, has been examined by assessing the location and extent of APP immunoreactivity. Increased APP immunoreactivity was present in both areas. This was localised to a circumscribed zone immediately adjacent to the boundary of the ischaemic lesion in grey matter. The amount of APP immunoreactivity was associated with the volume of the ischaemic lesion in individual animals. Increased APP immunoreactivity in subcortical white matter and myelinated fibre tracts at the margin of the ischaemic zone may prove to be a valuable marker for assessing strategies to protect axons after an ischaemic insult.

NMDA receptor blockade fails to alter axonal injury in focal cerebral ischemia.

The ability of the NMDA receptor antagonist, MK-801, to protect myelinated axons after focal cerebral ischemia has been examined. Amyloid precursor protein (APP) immunocytochemistry was used to assess the anatomic extent of axonal injury, and conventional histopathology was used to assess the volume of ischemic damage to neuronal perikarya. The middle cerebral artery was permanently occluded in 16 cats. The cats were treated with either vehicle or MK-801 as a 0.5-mg/kg bolus at 15 minutes before middle cerebral artery occlusion, followed by an infusion of 0.14 mg/kg per hour. After 6 hours, the animals were killed and the brains processed for histology and immunocytochemistry. The volume of neuronal necrosis was determined from 16 preselected coronal levels of the brain. The circumscribed zones of APP accumulation in axons were mapped onto images at the same 16 coronal levels, and quantitative analysis was performed using a transparent counting grid, randomly placed over each image. The histologic appearance and anatomic location of axons with increased APP immunoreactivity was similar in animals treated with vehicle and MK-801. MK-801 failed to reduce the hemispheric APP score significantly. In vehicle-treated animals, there was a significant association between the volume of neuronal necrosis and the amount of APP immunoreactivity. MK-801 significantly reduced the slope of the association between the volume of neuronal necrosis and the amount of APP immunoreactivity compared with that observed in vehicle-treated animals. As a result, the ratio of hemispheric APP score and volume of neuronal necrosis was significantly increased with MK-801 treatment. The inability of NMDA receptor antagonists to protect axons may limit their functional efficacy in improving functional outcome after stroke.

Prevalence and risk factors for feline obesity in a first opinion practice in Glasgow, Scotland

A cross-sectional questionnaire study of cat owners registered with a first opinion veterinary practice was undertaken in July 2008. The body condition score (BCS) of the cats was assessed by the interviewer using a validated five point scale. Owners also rated their cats BCS using five word descriptions. In total, 118 questionnaires were collected. The prevalence of overweight or obese cats (BCS 4 or 5) was 39% (30.2–47.8%, n=61). Risk factors associated with overweight or obesity were frequency of feeding and neutered status. There was moderate agreement between owner and interviewer rating of BCS. Owner misperception was more likely when owners rated cats with BCS 1 (very thin) and 4 (overweight) and in longhaired cats. The study highlights the continuing need for owner education in feline nutrition and specifically the requirement for veterinarians to develop strategies to help owners correct their assessment of their cats BCS.

An investigation into the epidemiology of feline obesity in Great Britain: results of a cross-sectional study of 47 companion animal practises

Previous epidemiological studies of feline obesity have been restricted to small geographical areas of Great Britain. This study represents the first published description of the prevalence and risk factors for obesity from a nationally distributed population of cats. Data were gathered from 3227 cats through 47 primary companion animal veterinary practises. The overall prevalence of overweight/obesity was 11.5 per cent (95% confidence interval 10.4 per cent to 12.6 per cent) in cats attending the charitys clinics. Cats in Scotland appeared to have a greater age and neutered-adjusted prevalence compared with cats in England. Neutered status, being male and middle age (around 7 years), were all significant risk factors for feline overweight/obesity, although they did not fully explain an individual cats risk of overweight/obesity. Breed was not found to be a statistically significant risk factor. Partial attributable fractions were calculated from each of the significant risk factors. Neutered status appeared to contribute the most to the prevalence of obesity, followed by prime/mature lifestage (3–10 years of age). Any interpretations of these findings should take into account the multitude of biases inherent in this study. Nevertheless, weight management following neutering appears to be very important to reduce the overall prevalence of overweight/obesity in this population of cats.

Topographical and quantitative assessment of white matter injury following a focal ischaemic lesion in the rat brain.

Axonal injury following cerebral ischaemia has attracted less attention than damage in grey matter. However, it is becoming increasingly recognised that axons are highly vulnerable to focal ischaemia [D. Dewar, D.A. Dawson, Changes of cytoskeletal protein immunostaining in myelinated fibre tracts after focal cerebral ischaemia in the rat, Acta. Neuropathol., 93 (1997) 71-77] [2]; [L. Pantoni, J.H. Garcia, J.A. Gutierrez, Cerebral white matter is highly vulnerable to ischemia, Stroke, 27 (1996) 1641-1647] [10]; [P. S. Yam, T. Takasago, D. Dewar, D.I. Graham, J. McCulloch, Amyloid precursor protein accumulates in white matter at the margin of a focal ischaemic lesion, Brain Res., 760 (1997) 150-157] [15]. Since white matter does not contain neuronal cell bodies or synapses it is likely that the mechanisms of injury and strategies for its protection are different from those in grey matter. In order that the effect of therapeutic intervention on the protection of axons can be assessed, a method by which axonal injury can be mapped and quantified is required. For this purpose, we investigated immunocytochemical methods using amyloid precursor protein (APP) following permanent middle cerebral artery occlusion in the rat. APP is transported by fast anterograde axonal transport [E.H. Koo, S.S. Sisodia, D.R. Archer, L.J. Martin, A. Weidemann, K. Beyreuther, P. Fischer, C.L. Masters, D.L. Price, Precursor of amyloid protein in Alzheimer disease undergoes fast anterograde axonal transport, Proc. Natl. Acad. Sci. U.S.A. 87 (1990) 1561-1565] [7] and has been shown to accumulate following a variety of insults to axons, indicative of dysfunction of axonal transport [R.N. Kalaria, S.U. Bhatti, E.A. Palatinsky, D.H. Pennington, E.R. Shelton, H.W. Chan, G. Perry, W.D. Lust, Accumulation of the beta amyloid precursor protein at sites of ischemic injury in rat brain, Neuroreport, 4 (1993) 211-214] [4]; [T. Kawarabayashi, M. Shoji, Y. Harigaya, H. Yamaguchi, S. Hirai, Expression of APP in the early stage of brain damage, Brain Res., 563 (1991) 334-338] [5]; [N. Otsuka, M. Tomonaga, K. Ikeda, Rapid appearance of beta-amyloid precursor protein immunoreactivity in damaged axons and reactive glial cells in rat brain following needle stab injury, Brain Res., 568 (1991) 335-338] [9]; [K. Shigematsu, P. L. McGeer, Accumulation of amyloid precursor protein in neurons after intraventricular injection of colchicine, Am. J. Pathol., 140 (1992) 787-794] [12]. We have been able to map the topographical relationship between APP accumulation and region of infarction using immunocytochemistry and image analysis techniques. Additionally, using a semi-quantitative scoring system, we have demonstrated that there is a relationship between the amount of APP accumulation and the volume of infarction following middle cerebral artery occlusion. These methods will be useful in the future for the assessment of therapeutic interventions on the protection of axons following ischaemic injury.

Validity, practical utility and reliability of Actigraph accelerometry for the measurement of habitual physical activity in dogs.

OBJECTIVES To test the validity, practical utility, and reliability of the Actigraph GT3-X accelerometer for measurement of habitual physical activity in pet dogs. METHODS In the validation study, 30 dogs wore the accelerometer for 1 day while being filmed. Accelerometer and film were synchronised and 10-minute periods of the filmed records were extracted with dogs in continuous periods of sedentary behaviour, light intensity physical activity indoors, light to moderate intensity physical activity outdoors and vigorous physical activity outdoors. For the practical utility and reliability studies, 20 dogs wore the GT3-X accelerometers for 1 week: practical utility was quantified as data loss and was also assessed by owner questionnaire; reliability was determined by 2 to 7 days of monitoring using the Spearman-Brown prophecy formula. RESULTS In the validation study, accelerometry output differed significantly between activity intensities (Friedman test, P<0·01). In the practical utility study, no data were lost from any dogs and dog owners reported that accelerometry was well tolerated. Reliability of accelerometry output was high: for 3 days of wear, it was 91% [95% confidence interval (CI) 82 to 96] and for 7 days of wear, it was 94% (CI 88 to 97). CLINICAL SIGNIFICANCE The GT3-X accelerometer is valid, practical and reliable for the measurement of habitual physical activity in dogs.

A cross sectional study of the prevalence and risk factors for owner misperception of canine body shape in first opinion practice in Glasgow.

The objectives of the study were to investigate whether owners were able to assign the correct body shape to their dog and to assess the dog and owner level factors associated with incorrect owner assessment of dog body shape. Six hundred and eighty questionnaires were administered to dog owners in 5 first opinion practices around Glasgow during July 2007. At the same time, the interviewer and owner assessed the body shape of each dog. The interviewer assessment of body shape was taken as the gold standard. Incorrect owner assessment of dog body shape (misperception) was divided into two groups: underestimation and overestimation. Multinomial logistic regression and classification and regression trees (CART) were used to assess risk factors associated with each type of misperception. Misperception of dog body shape was present in 44.1% of owners with underestimation (i.e. the owner considered the animal to have a leaner body shape from the gold standard assessment) being the most common form of misperception. Risk factors identified by both multinomial logistic regression and CART were gender of owner, age of the dog and dog body shape. The classification tree appeared to have improved predictive ability when compared to the multinomial model.

Current and future uses of breath analysis as a diagnostic tool

The analysis of exhaled breath is a potentially useful method for application in veterinary diagnostics. Breath samples can be easily collected from animals by means of a face mask or collection chamber with minimal disturbance to the animal. After the administration of a 13C-labelled compound the recovery of 13C in breath can be used to investigate gastrointestinal and digestive functions. Exhaled hydrogen can be used to assess orocaecal transit time and malabsorption, and exhaled nitric oxide, carbon monoxide and pentane can be used to assess oxidative stress and inflammation. The analysis of compounds dissolved in the aqueous phase of breath (the exhaled breath condensate) can be used to assess airway inflammation. This review summarises the current status of breath analysis in veterinary medicine, and analyses its potential for assessing animal health and disease.