Feline injection-site sarcomas (FISSs) are aggressive neoplasms that have been associated mostly with vaccination. Feline noninjection-site sarcomas (non-FISSs) are less frequently observed in cats and may arise in any anatomic site. This study aimed to determine the differences in the expression of the selected proteins (matrix metalloproteinase-2 (MMP-2), matrix metalloproteinase-9 (MMP-9), cyclooxygenase-2 (COX-2), and P-glycoprotein (PGP)) and their correlation with the mitotic count in FISS and non-FISS, in order to characterize their immunohistochemical features. A preliminary study of eleven samples of FISS and eight samples of non-FISS was performed using immunohistochemistry. Among all the tested sarcomas, 80.4% of the tumors were positive for COX-2, 90.2% were positive for MMP-9, and 100% were positive for PGP. The results showed that the expressions of COX-2, MMP-9, and PGP were significantly higher in FISS than in non-FISS (COX-2—p ≤ 0.001; MMP-9—p ≤ 0.05; and PGP—p ≤ 0.05). A Spearman rank correlation analysis showed a moderate negative correlation between the expression of COX-2 and MMP-9 in FISS (r = −0.52). A strong negative correlation between COX-2 and PGP (r = −0.81), a moderate positive correlation between MMP-2 and MMP-9 (r = +0.69), and a moderate negative correlation between MMP-2 and PGP (r = −0.44) were observed in non-FISS. In summary, our study presents the immunohistochemical profile of the proteins involved with inflammation and carcinogenesis in FISS and non-FISS, which can contribute to expanding the knowledge of tumor biology.

The reproductive cycle in domestic dogs involves prolonged phases of hormonal activity, making the endometrial tissue vulnerable to degenerative changes. One common result of these changes is cystic endometrial hyperplasia (CEH), which often leads to pyometra. Another, though rarer, condition is pseudo-placentational endometrial hyperplasia (PEH), characterized by abnormal proliferation of the endometrial glands and stroma, forming placental-like structures without the presence of pregnancy. Case presentation: An 8-year-old female Golden Retriever, healthy and intact, was presented for a routine ultrasound examination to confirm pregnancy after natural breeding 25 days earlier. Two previous pregnancies of this bitch have resulted in small but live litters. The ultrasound examination revealed multiple bilateral thickenings of the uterine horns, with ampullary-shaped enlargements measuring approximately 2.5 × 3.0 cm 25 days after breeding. The endometrium was conspicuously thickened, hypoechogenic, and either homogeneous or with scattered hyperechoic markings and faint striations. The mucosal surface ranged from regular to slightly irregular, and a small amount of hyperechoic condensed fluid was present in the lumen of the horns. No embryos were observed. Based on these findings, two primary diagnoses were considered: PEH or embryonic resorption sites, with a possible segmental uterine inflammation. A diagnosis suggestive of PEH was established through histopathological examination of the uterus after ovariohysterectomy, supported by consistent ultrasound findings that showed no progression or changes over time.

In recent years, special attention has been paid to proAKAP4, the precursor of A-kinase anchoring protein 4 (AKAP4), which plays a crucial role in the structure and function of the sperm flagellum. This testis-specific protein forms the fibrous sheath and local signal transduction required for proper sperm capacitation and motility. Highly conserved across species, proAKAP4 levels are strongly correlated with fertility and sperm survivability post-thaw. This review summarizes the biological roles of proAKAP4 and its potential as a semen quality biomarker in various mammalian species, including humans, horses, bulls, boars, dogs, rodents and other species. We discuss structural and molecular aspects of proAKAP4 (e.g., prodomain, PKA interactions, phosphorylation sites), as well as its involvement in key signaling pathways controlling sperm movement, such as the cAMP-PKA cascade and calcium signaling. The review also outlines various methods for measuring proAKAP4, such as ELISA, Western blotting and immunocytochemistry. Particular attention is given to commercial assays, which allow rapid and species-specific quantification of proAKAP4, independent of seminal plasma or cryoprotectant presence. Although the data are promising, researchers highlight the need for further validation in larger populations under varying environmental conditions. Nonetheless, current findings suggest that proAKAP4 may emerge as a standard marker in andrological diagnostics and a valuable tool for selecting breeding males and optimizing semen cryopreservation procedures.

Reproductive performance in roe deer can vary with age, body mass, and habitat, but the relationships among these factors remain incompletely understood. We examined ovarian morphometry and reproductive activity in 105 female roe deer harvested in four hunting grounds in central Poland during 2023–2026. Ovarian length, width, circumference, follicle number, and corpora lutea number and area were assessed in relation to female age, habitat type, and pregnancy status based on macroscopic embryo detection. Ovarian length, width, and circumference increased with age, with the main differences occurring between yearlings and older females. Field-harvested females had greater body mass than forest-harvested females, but habitat type, age class, and body mass did not significantly explain variation in follicle number, corpora lutea number, or corpora lutea area among sexually mature females. Embryos were not detected in October or November; they were detected in 8.3% of females in December and 49% in January. These findings indicate that ovarian dimensions increase with age, whereas reproductive traits in sexually mature females show no clear differences between habitat types. The timing of embryo detection should also be considered when assessing pregnancy from reproductive tract examinations.