The immunophenotype is regarded as an independent prognostic factor in high-grade lymphomas, seeing that lymphomas of T-cell origin are associated with shorter survival time. Although a number of studies have evaluated the immunophenotypical profile of lymphoma in the USA and Europe, Brazilian research on the matter remains scarce. Exact characterization of the histopathological type is crucial to establish proper treatment and prognosis. This study evaluated the database of immunohistochemistry laboratories that perform immunophenotyping of canine lymphoma in Brazil. A total of 203 cases of multicentric lymphoma were classified according to the WHO classification. Immunophenotyping was able to identify 71.4% lymphomas of B-cell line, 27.1% of T-cell line and 1.5% of non-B cells and non-T cell lines. Diffuse large B-cell lymphoma was the most common with 59.1% of the cases. Among T-cell lymphomas, lymphoblastic was the most common (11.33% of the cases). Even though canine lymphomas tend to be high-grade, indolent lymphomas comprised 11.82% of the cases and T-zone lymphoma was the most prevalent (8.86%). The immunophenotype of multicentric lymphoma in Brazil is similar to those in other parts of the world, which suggests similar etiologic factors to the development of this disease.

Epigenetic modifications have become highly important in the study of cancer pathogenesis due to research showing that changes in the expression of DNA-associated proteins can affect gene expression but may be reversible after treatment. The changing histones are being studied on a large scale in medicine while recent studies also show this relationship in veterinary medicine. Histone deacetylation is related to tumor progression and overexpression of histone deacetylases (HDACs) is responsible for these changes. The silencing of tumor suppressor genes related to epigenetic changes favors tumor progression; however, using HDAC inhibitors has been shown to effectively reverse these histone changes while having anticancer effects. This research provided an overview of comparative medicine between humans and dogs concerning epigenetic changes while showing the physiological mechanisms and the relationship between cancer and epigenetics, specifically regarding histone acetylation and deacetylation. This overview should contribute to a better understanding of epigenetics and cancer and their relationship with new target-molecular therapies in veterinary medicine and the importance of such studies.

Anatomopathological descriptions of infections caused by saprophytic algae in dogs are rare. This study reported the anatomopathological and microbiological findings suggestive of disseminated protothecosis in a dog residing in the state of Espírito Santo, Brazil. During necropsy, macroscopic alterations were observed in peripheral lymph nodes, heart, kidneys, pancreas, and lungs. Microbiological, cytological, and histopathological examinations were performed. Cytology and histopathology revealed piogranulomatous inflammation associated with sporangia and endospores, while microbiological culture suggested the growth of Prototheca spp.. These anatomopathological and microbiological findings were crucial for diagnosing and documenting the first case of disseminated Prototheca spp. compatible infection in a dog in the state of Espírito Santo, Brazil.

Epigenetic alterations play a crucial role in the pathogenesis of cancer, as changes in the expression of DNA‐associated proteins can affect gene expression. However, these changes may be reversible following treatment. This study aimed to evaluate the expression of acetylated histones H3 and H4 and the deacetylase enzymes HDACs 1, 2, and 6 in canine mammary tissues in order to identify potential alterations due to aberrant protein expression in neoplastic tissues. For this purpose, mammary tissue samples from 91 canine patients were divided into four groups: G1, control group composed of mammary tissues with no histopathological changes ( n = 11); G2, simple mammary adenomas ( n = 19); G3, simple mammary carcinomas without metastasis ( n = 46); and G4, simple mammary carcinomas with lymph node metastasis ( n = 15). The tissues were subjected to immunohistochemical analysis to assess protein expression. Antibody validation was performed by Western blot. The antibody expression results were evaluated semiquantitatively, considering the staining intensity and the percentage of marked cells. Univariate and multivariate analyses with a 5% significance level revealed differences in the expression of acetylated histones and deacetylase enzymes among the experimental groups ( p < 0.05). Reduced acetylation of H3 (H3K9Ac) was observed in both nonmetastatic and metastatic simple mammary carcinomas compared to normal mammary tissue. Additionally, lower expression of HDAC1 and HDAC2 was found in neoplastic mammary tissues compared to normal tissue ( p < 0.05). Conversely, HDAC6 exhibited higher expression in neoplastic mammary tissues ( p < 0.05). There was no difference in the expression of acetylated H4 (H4K12Ac) among the groups ( p > 0.05). Multivariate analysis showed a positive association between the expression of HDAC1 and HDAC2 and a negative association between H3K9Ac and HDAC6. These associations highlighted aberrant expression in mammary carcinomas compared to normal mammary tissues, indicating that epigenetic alterations exist in canine mammary neoplasms and that high HDAC6 expression may explain the observed hypoacetylation of H3 in neoplastic tissues. Collectively, these findings suggest that such alterations could potentially be therapeutic targets for the treatment of mammary cancer in dogs.

Resumo: Este estudo objetivou comparar os efeitos de duas doses de hiclato de doxiciclina sobre a contagem de hemácias, concentração de hemoglobina, hematócrito, contagem de leucócitos e plaquetas de cães com erliquiose. Foram estudados os grupos I, composto por cães saudáveis (n=6), negativos na sorologia para Ehrlichia canis e Leptospira spp., na PCR em tempo real para E. canis e Anaplasma platys e na semi–nested PCR para Babesia canis; grupos II (n=6) e III (n=6), compostos por cães com história clínica sugestiva, sorologia e/ou PCR em tempo real positivas para E. canis, e negativos na pesquisa de anticorpos anti-Leptospira spp., na PCR em tempo real para A. platys e na semi–nested PCR para B. canis. Os cães doentes foram tratados com hiclato de doxiciclina via oral a cada 12 horas por 30 dias (5 mg/kg, grupo II; 10 mg/kg, grupo III). Hemogramas foram feitos antes, decorridos 15 dias e aos 10 dias após o término dos tratamentos. Não houve diferenças entre os grupos nos tempos avaliados quanto às variáveis hemácias, hemoglobina, hematócrito e leucócitos. Observou-se diferença quanto aos trombócitos entre o grupo I e os grupos II e III (p<0,0001) no início do estudo. Aos 15 dias de tratamento, a média do grupo III foi menor que dos grupos I (p=0,008) e II (p=0,0007), indicando persistência da trombocitopenia, ausente no grupo II. Não houve diferença entre os grupos no tempo final, sugerindo que ambos os tratamentos promoveram aumento da contagem de plaquetas em cães naturalmente infectados por E. canis.