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<jats:title>Abstract</jats:title><jats:p>Our study provided a comprehensive characterization of the thorax of Shirazi cats by comparing the relevant soft and bone windows of computed tomography (CT) and magnetic resonance imaging (MRI) with cross, sagittal and coronal sectional anatomy. We outlined the mediastinum and its anatomic relationships with the trachea, oesophagus, lungs, heart, cranial and caudal vena cavae, and other thoracic structures using the data series gathered from adult normal Shirazi cats. The cranial mediastinum extended from the thoracic inlet to the 4th intercostal space, the middle mediastinum extended from the 5th and 7th intercostal spaces and was occupied by the heart and large blood vessels and the caudal mediastinum extended as a short and narrow portion from the 8th intercostal space to the diaphragm. The contents of the mediastinum and its relationship with the lungs and diaphragm were clearly presented in coronal‐sectional anatomy and CT slices. The diaphragm was clearly observed in the lung windows of the ventral thorax. Sagittal‐sectional anatomy and CT clarified the thorax's architecture and its contents, with higher density in the soft windows. The distribution of thoracic vessels on cross‐ and coronal‐contrast CT scans was clearly visible. In addition, MRI scans provided an excellent anatomic reference of the thorax with the help of cross, coronal and sagittal scans, especially in the heart and blood vessels. Our study provides a valuable atlas for the diagnosis of malformations of the thoracic structures and offers better assessments for helping veterinary radiologists and clinicians in diagnostic processes.</jats:p>

<jats:title>Abstract</jats:title><jats:p>The major and minor salivary glands are responsible for saliva production, a fluid drained in the oral cavity that will be involved in several functions at this level. The present study aimed to compare the microanatomy of the major (parotid, mandibular, sublingual) and minor salivary glands (von Ebner's and Weber's) of the Wistar rat, from a histological, histochemical and morphometrically point of view. Predominantly serous glands (parotid, mandibular and von Ebner's) showed differences in the secretion composition on both PAS and alcian blue reactions. The same observations were identified also for the mostly mucous salivary glands (sublingual and Weber). In terms of surface dimensions, the measurements suggested that the mucous acini have a greater surface compared with the serous ones, and, at the same time, a better‐represented polymorphism. In conclusion, the major and minor salivary glands in Wistar rats, a commonly used species in experimental procedures, showed similarities with other species including humans, but some structural traits are breed‐specific, this finding is very important for an extensive understanding of the morphophysiology of the salivary glands.</jats:p>

<jats:title>Abstract</jats:title><jats:p>Morphological changes in the late‐embryo‐stage gastrointestinal tract of Nigerian indigenous chicken were investigated using anatomical techniques. The paraffin‐embedded sections were stained with haematoxylin and eosin and periodic acid Schiff‐Alcian blue (pH 2.5) stains. During the late pre‐hatch period, the framework of the stomach was already established, but glands were yet poorly developed. Randomly oriented pre‐glandular cells in the lamina propria mucosae at embryonic day (ED) 14 became organized into elongated simple tubular glands at ED 19 and assumed adult morphology at post‐hatch day (PD) 1. Acidic and neutral mucin deposits were associated with the glandular cells. In the small intestine, enterocytes of the tunica epithelialis mucosae transformed from cuboidal‐shaped cells (at ED 14) to tall columnar cells (at PD 1). Short crypts of Lieberkühn, goblet cells, microfold cells and enteroendocrine cells were evident at ED 19, while the lamina propria mucosae and submucosa contained mesenchymal cells, reticular cells and isolated lymphoblasts. Similarly, the crypts, lymphoblasts, mesenchymal and reticular cells were also associated with the lamina propria mucosae and submucosa of the caecum and colorectum at ED 19. It was inferred from these findings that extensive cellular and tissue modifications occur in the gastrointestinal tract within the narrow window of the late pre‐hatch period. The definitive gut tunics, epithelium, glandular tissues, immune‐competent cells and tissues are formed as a result. Thus, the embryonic gut of the bird is made capable of assuming its necessary functions of food digestion, nutrient absorption, water and ion re‐absorption, immune surveillance, antibody production and immune responses at hatch.</jats:p>

<jats:title>Abstract</jats:title><jats:p>This study aimed to assess the sonographic features of abdominal organs in healthy captive Neotropical otters (<jats:italic>Lontra longicaudis</jats:italic>). The sonograph showed that the urinary bladder was located in the caudal abdomen and its content was uniformly anechoic. The bladder wall had three layers: outer hyperechoic serosa, hypoechoic muscular layer and hyperechoic mucosa. The mean total wall thickness was 0.10 cm. The splenic parenchyma had a homogeneous echotexture with greater echogenicity than that of the left renal cortex and liver. The borders were regular and tapered. Rugal folds were observed in the stomach when undistended. The mean gastric wall thickness was 0.28 cm and five distinct layers were visible. The liver had smooth contours, and division of the hepatic lobes was not precisely visualized. The hepatic parenchyma had a homogeneous echotexture with greater echogenicity as compared to the right kidney and lesser echogenicity than that of the spleen. The gallbladder appeared as an oval or rounded structure in the transverse plane, filled with homogeneous anechogenic content; the wall was thin, regular and hyperechoic, with a mean thickness of 0.09 cm. The kidneys had a lobulated appearance with renicular subunits. The mean total length of the kidneys in longitudinal plane was 6.18 cm for the left and 6.27 cm for the right. Each reniculus was covered by an echogenic capsule, and the medullary region was more hypoechogenic than the cortical region. In conclusion, sonographic features in most of the abdominal organs in Neotropical otters are similar to the ultrasound patterns observed in healthy dogs and cats, except for kidneys with reniculi.</jats:p>

<jats:title>Abstract</jats:title><jats:p>Telocytes (TCs) are distinctive interstitial cells due to their characteristic structures and heterogeneity. They are suggested to participate in tissue repair/regeneration. TCs have been identified in many organs of various mammals. However, data on TCs in lower animals are still very limited. In this work, TCs were identified in the myocardium of the bullfrog (<jats:italic>Rana catesbeiana</jats:italic>) by light and transmission electron microscopy (TEM). The structural relationships between TCs and neighbouring cell types were measured using the ImageJ (FiJi) morphometric software. TCs with slender Tps (telepodes) were located around cardiomyocytes (CMC). TEM revealed TCs with long Tps in the stroma between CMC. The homocellular tight junctions were observed between the Tps. The Tps were also very close to the neighbouring CMC. The distance between Tps and CMC was 0.15 ± 0.08 μm. Notably, Tps were observed to adhere to the periphery of the satellite cells. The Tps and the satellite cells established heterocellular structural connections by tight junctions. Additionally, Tps were frequently observed in close proximity to mast cells (MCs). The distance between the Tps and the MCs was 0.19 ± 0.09 μm. These results confirmed that TCs are present in the myocardium of the bullfrog, and that TCs established structural relationships with neighbouring cell types, including satellite cells and MCs. These findings provide the anatomical evidence to support the note that TCs are involved in tissue regeneration.</jats:p>

<jats:title>Abstract</jats:title><jats:p>Changes in the expression of nuclear β‐catenin are responsible for tumorigenesis. Beta‐catenin acts synergistically with the TGF‐β/BMPs pathway. This interaction leads to greater dentin deposition and may explain the differences between distinct tooth morphologies and hamartomas. The aim of this study was to investigate the role of β‐catenin, BMP4 and TGF‐β in the development of odontomas. This cross‐sectional, retrospective, immunohistochemical study evaluated 30 compound odontomas, 30 complex odontomas and 17 tooth germs. The results showed that BMP4 and TGF‐β were more immunoexpressed in the ectomesenchyme of complex odontomas (median = 33.7, <jats:italic>p</jats:italic> &lt; 0.001; median = 76.4, <jats:italic>p</jats:italic> = 0.002, respectively). Higher immunoexpression of BMP4 and TGF‐β was also observed in the epithelium of tooth germs (median = 2.0, <jats:italic>p</jats:italic> &lt; 0.001; median = 120.3, <jats:italic>p</jats:italic> &lt; 0.001, respectively). TGF‐β and BMP4 showed a positive and significant correlation (<jats:italic>p</jats:italic> &lt; 0.001). Both TGF‐β and BMP4 were positively correlated with nuclear β‐catenin in ectomesenchyme (<jats:italic>p</jats:italic> = 0.047 and <jats:italic>p</jats:italic> = 0.023, respectively). Developing teeth exhibited higher concentrations of the proteins studied in odontogenic epithelium, especially during the bud and cap stages. Higher immunoexpression in odontomas occurred mainly in the ectomesenchyme. We therefore suggest that changes in the ectomesenchyme can lead to the development of odontomas.</jats:p>

<jats:title>Abstract</jats:title><jats:p>Sertoli cells of sharks are non‐permanent components of the spermatocyst that they share exclusively with only one germ cell stage. After spermiation, all Sertoli cells, and thus the whole spent cyst, are disposed of in an area adjacent to the spermatozoal spermatocysts, that is, the resorption zone (RZ). Differences in the histology and magnitude of the RZ of the mature blue shark and Greenland shark correlate with differences in how spent cysts are dismantled. In the blue shark's RZ, the spent cyst's Sertoli nuclei were synchronously and stepwise fragmented into pyknotic bodies that were eventually resorbed in a whorl in the RZ interstitium. Conversely, cyst dismantling in the Greenland shark, that also lacked a spatially definitive RZ, revealed redundancy. One mode entailed the sloughing of the bulky Sertoli nuclei through an indistinct cyst–ductule transition area into its attached collecting ductule. A second mode entailed the asynchronous, progressive fragmentation of the bulky Sertoli nuclei into membrane‐enclosed pyknotic bodies. Both these modes solely entailed an internally coordinated demise of the spent cyst and whose basal lamina remained intact almost right to the end. Whatever the underlying mechanisms of these differences, these findings nonetheless reveal species‐specificity in the clearing up of the elasmobranch testicular parenchyma after the completion of a round of spermiogenesis. One consideration is the blue shark's expansive immune cell augmented RZ, that adjoins the animal's bone marrow equivalent tissue. The notable finding of a second conspicuous Sertoli cell type in the Greenland shark's spent cysts is also discussed.</jats:p>

<jats:title>Abstract</jats:title><jats:p>The Neotropical otter (<jats:italic>Lontra longicaudis</jats:italic>) is a mustelid distributed geographically from Mexico to Argentina. Anomalous origins of the aortic arch branches are rarely reported in wild carnivorans. Therefore, this study aimed to report the anomalous branching of the aortic arch in one formaldehyde‐fixed specimen of <jats:italic>L. longicaudis</jats:italic>. The aortic arch provided three branches: the bicarotid trunk and the left and right subclavian arteries. The latter passed dorsally to the esophagus toward the right side without a mark of compression at the esophagus. This is the first report of an anomalous origin of the right subclavian artery in <jats:italic>L. longicaudis</jats:italic>.</jats:p>

<jats:title>Abstract</jats:title><jats:p>Bali cattle (<jats:italic>Bos javanicus</jats:italic>) are a local breed from Indonesia with the potential for beef production, but its meat has been reported to be tough. This indicates that there is a need to develop various methods that can be used for assessment to improve the quality of the meat. One such method is muscle scoring (MS), which is often used to predict the amount of meat in the carcass from live animals, but the muscle microstructure contributing to the quality is often neglected. Therefore, this study aims to evaluate the correlation between the muscle score of Bali cattle and the quality of muscle microstructure in terms of myofibril morphometric and connective tissue composition using a histochemistry approach. The population consisted of 31 Bali cattle, and MS was performed by evaluating the muscle line using a range of 1 to 15. The three individuals with the highest scores (Hi) and the three with the lowest (Lo) were sampled for <jats:italic>semitendinosus</jats:italic> muscle microstructural observation. The results showed that cattle in the Hi group had a higher surface area of myofibril and sarcomere length, but had a significantly lower relative percentage of intramuscular collagen compared to others in the Lo group (<jats:italic>p</jats:italic> &lt; 0.05). Generally, muscle score had a positive correlation with body weight, surface area of myofibril and sarcomere length. In all cattle, the fibres identified were similar, where the thick types were dominant in the epimysium and perimysium, followed by the thin variants. Furthermore, the endomysium prominently contained non‐fibrous or other types of fibre. This study can provide the basic data that can be used as a pilot for future studies of muscle score assessment in Indonesian cattle.</jats:p>

<jats:title>Abstract</jats:title><jats:p>The current manuscript had been conducted to evaluate the effect of ageing on the brains of albino rats on the macro‐morphometric level and to assess the different parameters of brain and brain structures affected by ageing. Fifty apparently healthy rats of both sexes (27 males and 23 females) were used in the study, in addition to three rats for MRI. The animals were divided into four groups according to their age. Magnetic resonance imaging and cross sections of the brain were performed to document dimensions of various brain structures such as the hippocampus, surface area of lateral ventricle as well as dorsal and piriform cortices. Ageing would result into a negative impact on some brain structures. However, some others had not been affected as much. Furthermore, sex of the animal presented an important role as a variant where male rats of each age group demonstrated different results than their analogous female rats. In addition, MRI examination of the rat brain allowed recognition of the major cerebral structures. Findings of this work might be considered as a trial to provide a proof of changes resulted from normal ageing in both male and female rats and which sex is more affected than the other.</jats:p>