Paulo Salinas

Chronic exposure to fine particulate matter (PM_2.5) derived from wood combustion represents a major environmental health burden, particularly during pregnancy. However, the impact of pregestational and gestational (PM_2.5) exposure on the maternal great vasculature remains largely unexplored. This study evaluates the effects of wood smoke-derived (PM_2.5) on the structural architecture of the maternal aortic arch and associated hemodynamic changes during pregnancy in second-generation Sprague–Dawley rats. Animals were allocated into four groups (n = 12) according to filtered (FA) or non-filtered air (NFA) exposure during pregestational and gestational periods: FA/FA, FA/NFA, NFA/FA, and NFA/NFA. Morphometric analysis revealed significant reductions in tunica media (p = 0.0251) and adventitia thickness (p = 0.0014) in exposed groups, without changes in integrated optical density, suggesting alterations in elastic matrix organization without evidence of net mass loss. Histological analysis supported exposure-dependent structural heterogeneity, including elastic lamellae fragmentation and extracellular matrix disorganization. Each exposed group exhibited a distinct systolic blood pressure trajectory across gestation, with FA/NFA reaching the highest values at day 18 (151.0 ± 17.0 mmHg) and NFA/FA displaying sustained elevations despite gestational low-exposure conditions. Principal component analysis (49.2% explained variance) revealed a structured multivariate distribution of vascular and hemodynamic variables across exposure conditions, consistent with an exposure-window-dependent pattern. These findings suggest that (PM_2.5) exposure is associated with coordinated structural and hemodynamic changes in the aortic arch and support the hypothesis that the pregestational period may represent a window of increased susceptibility.

The Patagonian huemul (Hippocamelus bisulcus) and the Southern pudu (Pudu puda) are native South American cervids that differ in body size, ecology, and conservation status. However, quantitative evidence linking vertebral trabecular microarchitecture with biomechanical behavior in these species remains scarce. This study aimed to comparatively characterize vertebral trabecular bone structure and its mechanical response using an integrative, non-destructive approach. Vertebral bodies from cervical, thoracic, and lumbar regions were analyzed using high-resolution micro-computed tomography to quantify structural parameters, followed by finite element analysis to estimate deformation and von Mises stress under standardized axial compression. Both specimens exhibited consistent regional variation, with cervical vertebrae showing lower density and organization, and thoracic–lumbar vertebrae displaying denser trabecular networks. The Southern pudu specimen appeared to present a more homogeneous microarchitecture and a relatively uniform mechanical response along the vertebral column. In contrast, the Patagonian huemul specimen tended to show greater structural heterogeneity, with apparently higher deformation and stress values, particularly in the cervical region. These findings suggest that trabecular organization may contribute to the differences in vertebral mechanical behavior observed between the analyzed specimens. This study provides a preliminary comparative baseline for understanding skeletal adaptation and structural vulnerability in South American cervid species. This exploratory analysis is based on single specimens per species and should be interpreted as preliminary evidence rather than population-level inference.

The Patagonian huemul ( Hippocamelus bisulcus ), a critically endangered South American cervid, has undergone a severe population decline, and extant populations exhibit a high prevalence of skeletal disorders associated with chronic mineral deficiencies. Despite the biomechanical, postural, and clinical relevance of the axial skeleton, detailed information on its external morphology, internal architecture, morphometry, and elemental composition remains scarce for this species. Here, we address this gap by providing an integrative, multiscale characterisation of the postcranial axial skeleton of the Patagonian huemul. We hypothesised that the axial skeleton exhibits consistent regional patterns in external morphology, internal microarchitecture, and elemental composition identifiable using non‐destructive analytical approaches. Three complete axial skeletons were examined using macroscopic anatomical analysis and linear morphometry, helical computed tomography with three‐dimensional reconstruction, and semiquantitative energy‐dispersive X‐ray spectroscopy. Cervical, thoracic, lumbar, and sacral vertebrae, as well as ribs and sternum, were analysed following standardised veterinary anatomical terminology. CT imaging revealed regionally organised distributions of cortical and trabecular bone, including consistent basivertebral foramina and elongated internal cavities, together with segment‐specific variations in internal density. Elemental analysis of compact bone demonstrated variable proportions of principal constituents among axial regions, with lumbar vertebrae showing the highest relative mineral content. These findings establish a comprehensive anatomical reference framework for the axial skeleton of the Patagonian huemul, complementing previous descriptions of the appendicular skeleton and cranial structures.

Navicular syndrome (NS) is a chronic, degenerative condition of the equine thoracic limb that compromises the distal sesamoid bone (DSB) and associated structures responsible for stabilization and load absorption during locomotion. Although historically attributed to vascular alterations, its etiology is now recognized as biomechanical, characterized by chronic overload of the deep digital flexor tendon. Conventional diagnostic techniques—radiography, scintigraphy, and ultrasonography—lack the sensitivity and precision required to detect early microarchitectural alterations. This study aimed to evaluate changes in the trabecular microarchitecture of the DSB in horses with and without NS using micro‐computed tomography (micro‐CT) and to explore its diagnostic potential. Samples from eight horses (NS group, n = 4; Not affected group (control), n = 4) were analyzed. Micro‐CT images were processed to obtain parameters such as bone volume, relative density, trabecular thickness and separation, porosity, and connectivity. Group comparisons were performed using nonparametric tests and Pearson correlation analyses to explore internal structural relationships. Correlations between groups were then compared using Fisher's Z test. Horses with NS exhibited lower bone volume, trabecular density, thickness, and connectivity, alongside increased trabecular separation, porosity, and anisotropy compared to controls. In healthy horses, strong positive correlations between volume and density, and inverse relationships with trabecular fragmentation, indicated an elevated, well‐connected architecture. By contrast, affected horses displayed deteriorated microarchitecture with compensatory trabecular consolidation, reduced trabecular numbers, and a more cylindrical structure—signifying pathological adaptation. Two correlations differed significantly between groups, underscoring disease‐induced microstructural reorganization. Micro‐CT effectively identified navicular syndrome–specific microarchitectural changes not detectable with conventional methods, yielding quantifiable metrics (thickness, separation, and porosity) that may serve as early diagnostic and monitoring biomarkers. These findings justify broader studies with larger sample sizes and longitudinal designs to validate clinical applicability.

Postnatal testicular maturation in domestic cats remains poorly quantified despite its relevance for reproductive biology, veterinary practice, and the management of threatened felid species. This study aimed to characterize age-related changes in testicular structure from six to thirty-six months of age. Testes were collected from clinically healthy cats undergoing routine orchiectomy, and design-based stereology was used to estimate the volumes and densities of the main testicular components, including the seminiferous epithelium, interstitial tissue, Sertoli cells, and Leydig cells. Immunohistochemical detection of Desert Hedgehog, a developmental signaling molecule, was performed to assess interstitial maturation. Testicular volume and the absolute volumes of the seminiferous epithelium, Sertoli cells, and Leydig cells increased significantly with age, while the numerical density of Leydig cells remained stable, indicating hypertrophy rather than proliferation. Desert Hedgehog immunoreactivity declined progressively across age groups, consistent with the transition from immature to mature interstitial cells. Principal component analysis revealed a clear separation between immature and mature testes based on volumetric and density variables. These results demonstrate that feline testicular maturation follows a coordinated pattern of tubular and interstitial growth and provide quantitative reference values useful for reproductive assessment, comparative studies, and conservation programs in domestic and wild felids.

This study presents the development and preliminary validation of AutoScan3D, a portable and low-cost device for three-dimensional surface digitization of skulls using photogrammetry. The growing demand for accessible digitalization methods has encouraged the use of photogrammetry as a practical complement to high-end imaging technologies such as micro-computed tomography (micro-CT), which, although capable of visualizing internal structures with superior resolution, remains expensive and requires specialized facilities. AutoScan3D automates photographic capture through a smartphone camera, stepper motors, and an Arduino UNO controller. The system integrates a camera positioning module and an object rotation module to standardize image acquisition at fixed intervals. Its performance was evaluated by comparing the resulting 3D models with reference models derived from micro-CT scans to verify geometric accuracy and surface reconstruction fidelity. The results indicate that AutoScan3D reliably reproduces external morphology with realistic photographic textures and compact file sizes that facilitate subsequent manipulation in modeling software. Although its spatial resolution is lower than that of micro-CT, the device’s total hardware cost (≈USD 90) and ease of operation make it suitable for educational, demonstrative, and museographic contexts where external morphology is the main focus. Planned improvements include enhanced lighting control, compatibility with higher-resolution cameras, and a dedicated user interface. AutoScan3D thus provides a reproducible and affordable framework for surface-based three-dimensional digitization, expanding access to digital morphology tools in resource-limited settings.

The mandible of domestic dogs represents a key structure in veterinary anatomy. This study tested the hypothesis that mandibular shape variation in adult mesocephalic dogs follows a non-random modular pattern with limited allometric influence. A total of 168 dry mandibles from academic osteological collections were analyzed using geometric morphometrics. Four anatomical landmarks and two curves of sliding semilandmarks were digitized and processed through Generalized Procrustes Analysis. Principal component analysis revealed that 62.7% of total variance was concentrated in the first two axes, associated with the coronoid height, ramus robustness, and curvature of the mandibular body. Cluster and Canonical Variate Analyses identified two overlapping but statistically distinct configurations, reflecting the intrinsic morphological diversity of mesocephalic dogs. Procrustes regression confirmed a significant yet low allometric effect (2.34%), while modularity tests based on RV coefficients supported a structured organization involving the ramus, coronoid, and angular processes (processus angularis mandibulae) as relatively independent modules. These results indicate that mandibular shape variation is hierarchically organized rather than random, highlighting the coexistence of integration and modular independence within the masticatory apparatus. Beyond its morphometric contribution, this study provides a reproducible anatomical baseline for veterinary and comparative research, facilitating future analyses of sexual dimorphism, functional adaptation, and surgical applications.