The Veterinary Clinics of North America

Indices for M-mode measurements in dogs usually have been based on the assumption that a linear relationship exists between these measurements and body weight (BW) or body surface area (BSA). The relationships between the geometry of 3-dimensional objects do not support this assumption. The purposes of this study were to retrospectively examine M-mode data from a large number of dogs of varying sizes and breeds that were examined by a large number of ultrasonographers, to use the allometric equation to determine the appropriate BW exponent required to predict these cardiac dimensions, and to determine normal mean values and prediction intervals for common M-mode variables. Linear regression analyses of data from 494 dogs (2.2-95 kg) revealed a good correlation between M-mode measurements and BW after logarithmic transformation of the data (r2 = .55-.88). Most variables were most closely related to an index of body length, BW(1/3), although the exponent that best predicted diastolic and systolic left ventricular wall thicknesses was closer to 0.25. No variable indexed well to BW or BSA. With these data, appropriate mean values and prediction intervals were calculated for normal dogs, allowing veterinarians to correctly and appropriately index M-mode values. The equations developed from this study appear to be applicable to adult dogs of most breeds.

https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1939-1676.2004.tb02551.x

Allometric scaling of M-mode cardiac measurements in normal adult dogs.

Levels of recombination vary among species, among chromosomes within species, and among regions within chromosomes in mammals. This heterogeneity may affect levels of diversity, efficiency of selection, and genome composition, as well as have practical consequences for the genetic mapping of traits. We compared the genetic maps to the genome sequence assemblies of rat, mouse, and human to estimate local recombination rates across these genomes. Humans have greater overall levels of recombination, as well as greater variance. In rat and mouse, the size of the chromosome and proximity to telomere have less effect on local recombination rate than in human. At the chromosome level, rat and mouse X chromosomes have the lowest recombination rates, whereas human chromosome X does not show the same pattern. In all species, local recombination rate is significantly correlated with several sequence variables, including GC%, CpG density, repetitive elements, and the neutral mutation rate, with some pronounced differences between species. Recombination rate in one species is not strongly correlated with the rate in another, when comparing homologous syntenic blocks of the genome. This comparative approach provides additional insight into the causes and consequences of genomic heterogeneity in recombination.

/pdf/comparative-recombination-rates-in-the-rat-mouse-and-human-3b44cynqmi.pdf

Comparative recombination rates in the rat, mouse, and human genomes.

Hyponatremia

https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1939-1676.2009.0392.x

Guidelines for the Diagnosis and Treatment of Canine Chronic Valvular Heart Disease

The aim of this study was to provide two-dimensional (2D) and M-mode echocardiographic reference ranges from a sample of the UK population of donkeys including geriatrics (>30 years), owned by The Donkey Sanctuary, and to assess the influence of gender, weight and age on these variables. A total of 36 donkeys with no clinical or echocardiographic evidence of cardiovascular disease were examined; 24 geldings and 12 females, aged 3–45 years old, weighing 130–262 kg. Left atrial to aortic ratio was larger in geldings (P=0.004). There was no significant difference for left ventricular M-mode diastolic diameter between females and geldings (P=0.121) after exclusion of one heavy female outlier. 2D measurements significantly increased with bodyweight including maximal left atrial diameter (R2=0.112; P=0.046), aortic diameter at various levels (e.g. annulus: R2=0.35; P<0.001) and the pulmonary artery diameter (R2=0.124; P=0.035). M-mode measurements were not significantly influenced by weight other than the left ventricular free wall in systole (R2=0.118; P=0.041). Age and heart rate did not have any significant effect on echocardiographic variables. This is the first UK study to report on echocardiographic reference ranges of sedentary donkeys across a wide age range and shows differences compared with reference ranges from working donkeys.

Echocardiographic reference ranges for sedentary donkeys in the UK

Atrial fibrillation: onset and perpetuation.

Background Infective endocarditis (IE) in dogs is associated with severe disease and a high case fatality rate but often presents with nonspecific clinical signs. Hypothesis/objectives Serum concentration of cardiac troponin-I (cTnI) is elevated in dogs with IE and can differentiate dogs with IE from dogs with other diseases with similar clinical features. Concentration of serum cTnI is negatively correlated with survival time in dogs with IE. Animals Seventy-two client-owned dogs; 29 with IE, 27 with stage-B myxomatous mitral valve disease (MMVD), and 16 with immune-mediated disease (IMD). Methods Retrospective clinical cohort study. Concentration of serum cTnI was measured in all dogs at time of diagnosis. Clinical findings and echocardiographic interpretation were also recorded. Statistical analyses included Kruskal-Wallis test, pairwise Mann-Whitney U tests, receiver operator characteristic, and Cox proportional hazards. Results Serum concentration of cTnI was significantly higher in the IE group (0.69 ng/mL [0.03-80.8]) than in the MMVD (0.05 ng/mL [0.02-0.11], P Conclusions and clinical importance Cardiac troponin-I concentrations are higher in dogs with IE compared to dogs with preclinical MMVD or IMD. In dogs with a compatible clinical presentation, serum cTnI concentrations >0.625 ng/mL are supportive of IE.

https://onlinelibrary.wiley.com/doi/pdf/10.1111/jvim.16234

Joanna Dukes-McEwan

Papers

Echocardiographic reference ranges for sedentary donkeys in the UK

Atrial fibrillation: onset and perpetuation.

Evaluation of serum cardiac troponin-I concentrations for diagnosis of infective endocarditis in dogs.

Cytokine and matrix metalloproteinase expression in blood samples of dogs with congestive heart failure.

Usefulness of pulsed-wave tissue Doppler imaging at the mitral annulus for prediction of new-onset atrial fibrillation in dogs