The relationships between sediment findings and culture results and the presence of proteinuria in canine urine samples.

OBJECTIVES: To assess relationships between urine sediment and microbial culture findings and the presence of proteinuria in canine urine samples, and to assess the change in the percentage of proteinuric samples and urine protein-to-creatinine ratio when urine abnormalities resolve. MATERIALS AND METHODS: Canine urine samples collected via cystocentesis and submitted for culture and contemporaneous urinalysis (including urine protein-to-creatinine ratio) were retrospectively identified. Dogs receiving corticosteroids were excluded. Associations between haematuria (red blood cells>5/high-power field), pyuria (white blood cells>5/high-power field), presence of microorganisms on microscopy, active sediment, and positive culture and proteinuria (urine protein-to-creatinine ratio>0.5) were investigated. Patient characteristics were considered possible confounders. In dogs with repeat urinalysis, the associations between active sediment and positive culture resolution on proteinuria and urine protein-to-creatinine ratio were assessed. RESULTS: One hundred and ninety-two of 491 samples were proteinuric (39.1%). Age was positively associated with proteinuria. In the multivariable analysis corrected for age, active sediment was the only variable significantly associated with proteinuria (adjusted odds ratio: 2.12; 95% confidence interval: 1.44 to 3.11); however, only 49.8% of samples with active sediment were proteinuric. Neither resolution of active sediment nor positive culture were associated with reduced proportions of proteinuric samples (from 57.9% to 42.1% and from 40.0% to 25.0%, respectively) or significant reductions in urine protein-to-creatinine ratio (median change: -0.16 and -0.14, respectively). CLINICAL SIGNIFICANCE: Attributing proteinuria to urinalysis abnormalities or a positive urine culture in canine cystocentesis samples is not supported by our findings, and could result in alternative causes of proteinuria (e.g. renal proteinuria) being overlooked.

Hair nicotine concentration measurement in cats and its relationship to owner-reported environmental tobacco smoke exposure.

OBJECTIVES: To investigate the association between hair nicotine concentration in cats and owner-reported exposure to environmental tobacco smoke. MATERIALS AND METHODS: Owner questionnaires documented exposure. Nicotine was extracted from hair by sonification in methanol followed by hydrophilic interaction chromatography with mass spectrometry. Relationships between hair nicotine concentration and owner-reported exposure were examined using hypothesis-testing statistics and receiver operating characteristic curve analysis. RESULTS: The hair nicotine concentration of reportedly exposed cats was significantly higher than unexposed cats and groups of cats with different levels of exposure had significantly different median hair nicotine concentrations corresponding to exposure. A hair nicotine concentration of 0·1 ng/mg had a specificity of 98% (95% confidence interval: 83 to 100) and a sensitivity of 69% (95% confidence interval: 54 to 84) for detecting environmental tobacco smoke exposure. Outdoors access, coat colour, urban or rural environment and length of time living with the owner were not obviously associated with hair nicotine concentration. CLINICAL SIGNIFICANCE: Feline hair nicotine concentration appears strongly associated with owner-reported environmental tobacco smoke exposure. Feline hair nicotine concentration could therefore be used as a biomarker for tobacco smoke exposure, allowing future studies to assess whether exposed cats have an increased risk of specific diseases.

The effect of magnetic resonance imaging noise on cochlear function in dogs.

Noise produced by magnetic resonance imaging (MRI) scanners (which can peak at a sound pressure level of 131 dB) has been shown to cause noise-induced cochlear dysfunction in people. The aim of this study was to investigate whether noise produced during MRI had a deleterious effect on cochlear function in dogs, using distortion product otoacoustic emission (DPOAE) testing, which allows frequency specific, non-invasive assessment of cochlear function. DPOAE testing was performed before and after MRI in one or both ears under general anaesthesia at 14 frequency pairs (f2 frequency ranging from 0.84 kHz to 8.0 kHz). A control group comprised dogs undergoing anaesthesia of a similar duration for quiet procedures. Thirty-six dogs (66 ears) and 17 dogs (28 ears) were included in the MRI and control groups respectively. There was a reduction in DPOAE at all frequencies tested in the MRI group; a similar effect was not evident in the control group. This reduction in the MRI group was statistically significant in five of the 14 frequencies assessed (P < 0.05). These results demonstrate that exposure to MRI noise results in a significant reduction in frequency-specific cochlear function in dogs, although it is not known whether this is reversible or permanent. This suggests that all dogs undergoing MRI studies should be provided with ear protection as a routine precautionary measure.

Comparison of rectal, tympanic membrane and axillary temperature measurement methods in dogs.

The aim of this study was to compare axillary and tympanic membrane (TM) temperature measurements to rectal temperature in a large group of clinical canine patients. We also sought to ascertain whether certain factors affected the differences between the measurements and to compare the ease of measurement. Axillary temperatures were easy to obtain but tended to be lower than rectal readings (median difference 0.6°C). In 54.7 per cent of dogs there was a difference of >0.5°C between the two readings. Weight, coat length, body condition score and breed size were significantly associated with the difference between the rectal and axillary temperature. TM temperatures were more similar to rectal temperatures (median difference 0°C) but in 25 per cent of dogs, there was a difference of >0.5°C between rectal and TM readings. TM measurements were less well tolerated than axillary measurements. None of the factors assessed were associated with the difference between the rectal and TM temperature. As a difference of >0.5°C has previously been described as unacceptable for different methods of temperature measurement, neither axillary nor TM temperatures are interchangeable with rectal temperatures for the measurement of body temperature.