Quantification of Global DNA Methylation in Canine Mammary Gland Tumors via Immunostaining of 5-Methylcytosine: Histopathological and Clinical Correlations.

Mammary tumors are the most prevalent neoplasms in non-neutered female dogs, with genetic and epigenetic alterations contributing to canine mammary carcinogenesis. This study quantified global DNA methylation in 5-methylcytosine (5mC)-immunostained canine mammary tumor samples and established histopathological and clinical correlations. A total of 91 formalin-fixed paraffin-embedded mammary tumor samples from female dogs were retrospectively selected and subjected to immunohistochemistry using an anti-5mC mouse monoclonal antibody. We evaluated 5mC+ stained nuclei of neoplastic epithelial cells in canine mammary glands to obtain semiquantitative histoscores based on staining intensity. Survival rates were estimated based on owners' or veterinary records. Histological samples comprised 28 and 63 benign and malignant canine mammary gland tumors, respectively. Results revealed significant differences between global DNA methylation patterns when mammary samples were categorized as benign or malignant (p = 0.024), with hypomethylated patterns more prevalent in malignant tumors and those with higher relapse behavior (p = 0.011). Of note, large diameter (>5 cm) tumors revealed a lower methylation pattern (p = 0.028). Additionally, we found non-statistically significant differences when tumors were grouped by histopathological characteristics, clinical parameters, or survival. These findings propose global DNA methylation assessment as a promising tool for detecting canine mammary tumors with relapse propensity.

Comparative study of 4 echocardiographic methods of left ventricular measurement in German Shepherd dogs.

OBJECTIVES: To compare dimensions and shortening fraction (SF) of the left ventricle (LV) obtained from two-dimensional (2D) and M-mode imaging of short and long-axis views. ANIMALS: 40 healthy, adult German Shepherd dogs. METHODS: Left ventricular measurements were obtained using 4 echocardiographic methods: M-mode in short and long-axis and 2D imaging in short and long-axis. The methods were compared by studying the effects of imaging mode and axis on LV parameters, taking into account the influence of weight and gender. RESULTS: Mean LV end-diastolic diameter was greater in short-axis views. However, this difference was not considered clinically relevant. Mean SF was higher when derived from 2D measurements with poor agreement among methods. A combined influence of axis, gender, and weight was observed on interventricular septal thickness in end diastole with poor agreement among methods. CONCLUSIONS: Some LV parameters were significantly affected by mode and axis, either in isolation or in combination with weight and gender, although the differences observed were not always clinically relevant. These findings show that using the different echocardiographic methods interchangeably to assess LV dimensions should be done with caution.

Prevalência da doença degenerativa valvar crônica mitral em cães / Prevalence of mitral valve chronic degenerative disease in dogs

Objetivo - A doença degenerativa da valva mitral (DDVM) é, dentre as alterações adquiridas, a cardiopatia de maior ocorrência em cães geriatras, sendo mais frequentemente observada em cães machos de pequeno e médio porte. A degeneração valvar ocasiona distorção dos folhetos, com consequente regurgitação mitral que determina sobrecarga de volume e dilatação de átrio esquerdo, com consequente insuficiência cardíaca congestiva (ICC) esquerda, ou mesmo hipertensão pulmonar secundária e ICC direita nos casos mais graves. O objetivo do presente estudo foi avaliar a predisposição etária, racial e sexual dos cães acometidos por DDVM em nosso meio. Métodos - Foram avaliados 125 cães, nos quais o diagnóstico de DDVM foi suspeitado por anamnese, auscultação cardíaca, eletrocardiografia e radiografia torácica, sendo confirmado por meio de ecocardiografia. Resultados - Observou-se, em relação à faixa etária dos cães acometidos, média e desvio padrão de 11,6 ± 2,4 anos, variando de 5 a 18 anos de idade. As raças de cães mais frequentemente acometidas foram aquelas de pequeno e médio porte, observando-se a seguinte frequência de ocorrência: Poodle (38,0%), SRD (32,0%), Pinscher (8,0%), Cocker Spaniel (5,0%), Dachshund (6,0%), Lhasa Apso, Maltês e Pastor Alemão (2,0% cada) e outras (1,0% cada). Evidenciou-se maior predisposição dos machos à DDVM, observando-se sua ocorrência em 74 machos (59,0%) e 51 fêmeas (41,0%). Conclusão - Por meio deste estudo epidemiológico, ressalta-se a importância da avaliação cardiológica periódica dos animais mais suscetíveis à DDVM, tais como os cães machos idosos de raças pequenas, buscando-se diagnosticar precocemente essa prevalente doença.

Objective - Degenerative disease of mitral valve (DDMV) is among the acquired heart disease most prevalent in geriatric dogs, being more frequently observed in small and medium male dogs. The degeneration causes distortion of the valve leaflets, with consequent mitral regurgitation that determines volume overload and dilatation of the left atrium with consequent left congestive heart failure (CHF), or secondary pulmonary hypertension and right CHF in severe cases. The aim of this study was to evaluate the age, racial and sexual predisposition of dogs affected by DDMV in our environment. Methods - A total of 125 dogs were evaluated, in whom the diagnosis of DDMV was suspected through history, cardiac auscultation, electrocardiography and chest radiography, and confirmed by echocardiography. Results - Regarding the age of affected dogs, it was encountered mean and standard deviation of 11,6 ± 2,4, ranging from 5 to 18 years old. The breeds of dogs most frequently affected were those of small and medium size, noticing the following frequency of occurrence in various breeds: Poodle (38.0%), SRD (32.0%), Pinscher (8.0%), Cocker Spaniel (5.0%), Dachshund (6.0%), Lhasa Apso, Maltese and German Shepherd (2.0% each) and others (1.0% each). It was observed a higher susceptibility of males to DDMV, identifying its occurrence in 74 males (59.0%) and 51 females (41.0%). Conclusion - This epidemiological study emphasizes the importance of regular cardiac evaluation of the animals more susceptible to DDMV, such as elderly male dogs of small breeds, seeking an early diagnosis of this prevalent disease.