Macroscopic and histological aspects of the pharynx and larynx of the giant anteater (Myrmecophaga tridactyla Linnaeus, 1758).

Giant anteater (Myrmecophaga tridactyla) is an endangered species that resides in much of Latin America, but it has been losing its habitat, especially in the Cerrado biome, where it constantly suffers traumas resulting from fires and roadkill. The anatomical knowledge of structures of the respiratory system is important for a better morphophysiological understanding of the species. Thus, this study aimed to perform the macroscopic and histomorphological description of the pharynx and larynx of the giant anteater. Twelve adult giant anteaters were used, three of them fixed in buffered formalin for further dissection and pharynx and larynx macroscopic analysis of structures. From the other animals, samples of the pharynx and larynx were collected and prepared for histological evaluation under optical microscope. Macroscopically, their pharynx and soft palate are extensive, and the anatomical location of these structures and the larynx differs greatly from that described in other species. The larynx, although more caudal, was similar to that of other animals. Histologically, the epithelium of these regions varied between the pseudostratified ciliated columnar and the non-keratinized stratified squamous epithelium. Laryngeal cartilages were composed of elastic (epiglotti) and hyaline cartilages (arytenoid, cricoid and thyroid cartilage), with an ossification process and glandular clusters around the hyaline cartilage. The distinct anatomical location of the pharynx and larynx of Myrmecophaga tridactyla is the main macroscopic finding of this study, besides the length of the pharynx and soft palate of these animals.

Comparative Pathobiology of Canine and Human Prostate Cancer: State of the Art and Future Directions.

First described in 1817, prostate cancer is considered a complex neoplastic entity, and one of the main causes of death in men in the western world. In dogs, prostatic carcinoma (PC) exhibits undifferentiated morphology with different phenotypes, is hormonally independent of aggressive character, and has high rates of metastasis to different organs. Although in humans, the risk factors for tumor development are known, in dogs, this scenario is still unclear, especially regarding castration. Therefore, with the advent of molecular biology, studies were and are carried out with the aim of identifying the main molecular mechanisms and signaling pathways involved in the carcinogenesis and progression of canine PC, aiming to identify potential biomarkers for diagnosis, prognosis, and targeted treatment. However, there are extensive gaps to be filled, especially when considering the dog as experimental model for the study of this neoplasm in humans. Thus, due to the complexity of the subject, the objective of this review is to present the main pathobiological aspects of canine PC from a comparative point of view to the same neoplasm in the human species, addressing the historical context and current understanding in the scientific field.

Morphological and Molecular Characterization of Proliferative Inflammatory Atrophy in Canine Prostatic Samples.

Proliferative inflammatory atrophy (PIA) is an atrophic lesion of the prostate gland that occurs in men and dogs and is associated with a chronic inflammatory infiltrate. In this study, we retrospectively reviewed canine prostatic samples from intact dogs, identifying 50 normal prostates, 140 cases of prostatic hyperplasia, 171 cases of PIA, 84 with prostate cancer (PC), 14 with prostatic intraepithelial neoplasia (PIN) and 10 with bacterial prostatitis. PIA samples were then selected and classified according to the human classification. The presence of PIA lesions surrounding neoplastic areas was then evaluated to establish a morphological transition from normal to preneoplastic and neoplastic tissue. In addition, the expression of PTEN, P53, MDM2 and nuclear androgen receptor (AR) were analyzed in 20 normal samples and 20 PIA lesions by immunohistochemistry and qPCR. All PIA lesions showed variable degrees of mononuclear cell infiltration around the glands and simple atrophy was the most common histopathological feature. PIA was identified between normal glands and PC in 51 (61%) out of the 84 PC samples. PIA lesions were diffusely positive for molecular weight cytokeratin (HMWC). Decreased PTEN and AR gene and protein expression was found in PIA compared to normal samples. Overall, our results strongly suggest that PIA is a frequent lesion associated with PC. Additionally, this finding corroborates the hypothesis that in dogs, as is the case in humans, PIA is a pre neoplastic lesion that has the potential to progress into PC, indicating an alternative mechanism of prostate cancer development in dogs.

Effects of the Latex of Synadenium grantii Hook F. (Euphorbiaceae) on a Preclinical Model of Canine Prostate Cancer.

Prostatic cancer (PC) stands out in terms of its occurrence, pathophysiology, and unfavorable prognostics in humans and dogs. Natural drugs bear an integrative potential for conventional antineoplastic treatments. In this context, the bioproducts of Synadenium grantii have been empirically used in different parts of Brazil for the integrative treatment of prostate cancer in humans. However, there is no availability of scientific evidence of the antitumor effects of S. grantii. Therefore, this study aimed to investigate the bioactive compounds in the latex of S. grantii using the high-resolution mass spectrophotometry (HRMS) and to evaluate its cytotoxic effects on primary canine PC cell cultures. Four fragments of phorbol ester were identified as potential bioactive compounds using the HRMS. With the help of an MTT ([3-(4,5-dimethyldiazol-2-yl)-2,5 diphenyltetrazolium bromide]) assay, two canine prostatic carcinoma cell lines (PC 1 and PC2) showed a decrease in the tumor cell count, with an Inhibitory concentration 50 (IC50)of 0.8469 and 0.6068 mg/ml, respectively, for PC1 and PC2. In conclusion, the latex of S. grantii contains phorbol esters in its composition, and its aqueous solution has a cytotoxic effect on canine metastatic PC cells in vitro.