Anatomia Histologia Embryologia最新文献

Understanding the anatomy of alpaca (Vicugna pacos) paranasal sinuses is essential for accurate interpretation of diagnostic imaging and surgical planning, especially given the species' susceptibility to dental disease and associated sinusitis. However, detailed anatomical and volumetric data on alpaca sinuses remain limited. This study aimed to characterise the volumetric properties and anatomical composition of the paranasal sinuses in alpacas using semi-automated segmentation of computed tomography datasets, with the goal of supporting clinical practice in veterinary medicine. Seven adult alpaca heads were scanned using computed tomography, followed by semi-automated segmentation and three-dimensional reconstruction. All specimens displayed the dorsal conchal sinus (sinus conchae dorsalis), middle conchal sinus (sinus conchae mediae), maxillary sinus (sinus maxillaris), frontal sinus (sinus frontalis), and lacrimal sinus (sinus lacrimalis). The sphenoid sinus (sinus sphenoidalis) was present in six out of seven animals. Marked inter-individual anatomical variation was noted, particularly in the frontal sinus and sphenoid sinus. Despite this variability, sinus volumes were generally symmetrical between the left and right sides, with no statistically significant differences. The frontal sinus had the largest mean volume, with values of 13.75 ± 6.70 cm³ on the left and 13.91 ± 7.22 cm³ on the right. Statistical analysis revealed no significant correlations between sinus volume and sex, age, or estimated craniofacial volume. Coefficients of variation exceeded 50% in most sinus compartments, emphasizing substantial individual variability. Three-dimensional models highlighted the complex morphology and spatial variation among specimens. This study provides novel insights into the sinonasal anatomy of alpacas, demonstrating a high degree of individual variation despite general bilateral symmetry. These findings emphasize the need for species-specific anatomical references and can aid in improving diagnostic accuracy and surgical outcomes in clinical settings. The three-dimensional reconstructions offer a valuable educational resource for veterinary professionals.

The transcription of ribosomal genes (rDNA) and precursor rRNA (pre-rRNA) processing are crucial biological processes in ribosome biogenesis. Yet, the specific impact of ribosome biogenesis on the first lineage differentiation during early mouse embryonic development remains unclear. Nucleolar proteinLy-1 antibody reactive clone (LYAR) can accelerate ribosome production, regulating rDNA transcription and pre-rRNA maturation. Our study employed immunofluorescence and quantitative polymerase chain reaction (qPCR) to investigate the presence and localization of LYAR during early mouse embryonic development. The interference fragments and mRNA of LYAR were separately injected into embryos at the pronuclear stage, and the embryo development was statistically analysed. The impact of regulating LYAR expression on the first lineage differentiation was determined by immunofluorescence staining, At the 2-cell stage, regulatory fragments and RFP mRNA were injected into a single blastomere. By immunofluorescence staining to determine the proportion of blastomeres with regulated LYAR expression contributing to the ICM. The influence of interfering with LYAR expression at the pronuclear stage on the overall level of newly synthesised rRNA was detected by EU staining. Finally, qPCR was used to further determine the impact of regulating LYAR expression on rDNA transcription and pre-rRNA processing. The results demonstrate that LYAR is detectable at various stages of preimplantation development. Importantly, as embryonic development progresses, LYAR gradually translocates from the cytoplasm and nucleus into the nucleolus. Knockdown of LYAR during the pronuclear stage results in a reduction in the number of ICM following the first lineage differentiation of embryonic development. Furthermore, modulating the expression of LYAR in individual blastomeres at the 2-cell stage affects their contribution to the ICM, altering the proportion of cells that contribute to the blastocyst. Our study hints a link between ribosome biogenesis and the first lineage differentiation, contributing to a better understanding of the mechanisms underlying mouse embryonic development.

Dissection and plastination of the nervous system have been used to teach anatomy; however, there is no record of a dissection and plastination of a dog's complete nervous system. The objective of this study was to dissect and preserve the whole nervous system of a dog, using the plastination technique, as a tool for teaching veterinary neuroanatomy. A 7-month-old dog was perfused through the common carotid artery with an ethanol-based soft embalming solution, and 10% formalin was injected through the cisterna magna. An incision was made at the level of the dorsal midline, and the muscle tissue from this area was removed, as well as the vertebral laminae and pedicles with a rib shear to clear the dorsolateral region of the vertebral column and to expose the spinal cord. Then, every nerve was individualised by blunt dissection. The soft tissue of the head was removed to visualise the skull, which was incised with a rib shear and rotary tool until the brain was exposed. Finally, the entire nervous system was removed in one piece and plastinated for conservation through the Biodur S10 technique. A specimen of the nervous system was obtained that included the brain, the spinal cord with its meninges, the cervical plexus, the brachial plexus, the intercostal and abdominal nerves, the lumbosacral plexus, the sympathetic trunk, the vagus nerve, and the phrenic nerves. We implemented an alternative preservation technique that minimised the use of formalin, which yielded satisfactory results while reducing the handling of toxic agents. The model obtained allows a total visualisation of the nervous system. It is expected to be helpful for the understanding of this complex anatomical system.

Assessments of the tongue morphology contribute to the understanding of evolutionary processes associated with food and feeding habits. In this sense, this study aimed to describe the tongue morphology in the Spinner dolphin (Stenella longirostris) and understand possible morphological associations with its food and feeding habits. Macroscopic dissections and light as well as scanning electron microscopy analyses of three Spinner dolphin tongues were performed. The tongues are elongated and exhibit a dorsal surface divided into three regions, namely the apex, the body and the root. Two types of lingual papillae, marginal and vallate papillae, were identified. Microscopically, the tongue is composed of a Tunica mucosa and a muscle layer, the Musculus lingualis proprius. The epithelial lining of the Tunica mucosa is a cornified stratified squamous epithelium. No taste buds were found in any of the identified lingual papillae. The Lamina propria mucosae is formed by loose and dense connective tissue and contains compound tubuloacinar glands with serous and mucous cells and the excretory ducts open on the lingual surface. Serous cells were positively stained by PAS, whereas mucous glands were positively stained by Alcian blue. The muscle layer is composed of striated muscle with longitudinal, transverse, and oblique bundles. Thus, Spinner dolphin tongues are similar to those of other odontocetes with only two types of lingual papillae and many lingual glands. Taste buds are absent. Based on the morphology, we hypothesize that the main function of the tongue in the Spinner dolphin is to aid in swallowing whole prey.

The tongue, which has a unique mucosal structure, undertakes the task of taking food in living things, turning it into morsels, and transmitting it to the oesophagus. This study aimed to investigate the development of tongue papillae in young (lamb) and adult (ram) Hamdani sheep (Ovis aries) by comparing light and electron microscopic features and morphometric characteristics. Tongue tissues of 7 crossbred Hamdani lambs aged 4–6 months and 7 rams aged 1–2 years were used in the study. Tongues were evaluated macroscopically and morphometrically, and light microscopic and scanning electron microscopic descriptions were also performed. In addition to light microscopic identification, parameters such as papillae height, papillae width, epithelial height, and stratum corneum thickness were measured. The morphometric and histometric data were evaluated statistically. The results demonstrated age-related statistical differences in the number of fungiform and vallate papillae (p < 0.05). In rams, epithelial and papilla heights were higher for all papilla types, indicating that tongue tissue develops with age. The higher number of taste papillae in lambs suggests better taste perception in young animals, whereas the increased stratum corneum on filiform papillae in rams indicates more intensive use of the tongue during food intake. In conclusion, tongue papilla morphology shows age-related variations, with both lambs and rams exhibiting distinct morphological features across different papilla types.

A detailed light and electron microscopic study of the retina was performed to provide comprehensive data on its different layers for the evaluation and conclusions concerning experimental observations, as pigs have been extensively used as experimental animals. The central retinas from 12 adult pigs (> 2 years) of local mixed breed were studied to explore the retina. The light and ultrastructural study revealed the complex laminar organisation and cellular composition of the retina. The retinal pigmented epithelium is the outermost layer and their nuclei are usually oval in shape, located basally, with their long axis parallel to the length of the retina. The outer and inner segments of photoreceptors showed an intense reaction to Alcian blue and colloidal iron for acidic mucopolysaccharides, while the inner segments of these cells showed a weak to moderate reaction to PAS. Outer segments of both rods and cones are covered by a plasma membrane, but during the renewal and shedding of discs, the plasma membrane loses its continuity towards the scleral side. The basal and vitreal parts of the outer segment were covered by cytoplasmic prolongations (calyces) of their inner segments. Mitochondria were numerous and densely packed in the ellipsoid of cones, whereas they were fewer and elongated in rods. A noteworthy finding in the present study is the presence of electron-dense rounded structures surrounded by mitochondria in the ellipsoid of cones. The outer limiting membrane was formed by the zona adherens between the cell membrane of the inner segment of the rods and cones and the fibres of the Müller cells, as well as between Müller cells. The axons of the rods terminated in dilated oval-shaped spherules, while cones formed pyramidal-shaped pedicles that formed synaptic complexes with bipolar and horizontal cells. The synaptic ribbon, an electron-dense linear structure and arciform density was observed within the rod spherules adjacent to the synaptic complex. The lateral surface of the spherules was in close contact with the same surface of the cones' pedicles, but no specific cell junctions were observed. The nuclei of bipolar cells were usually round and situated in the mid-portion of the inner nuclear layer, mostly containing electron-dense materials. The nuclear material of horizontal cells was usually euchromatic, with some electron-dense material also present. Few mitochondria, free ribosomes, smooth and rough endoplasmic reticulum and microtubules were observed in the perikaryon of the horizontal cells. A comprehensive light and ultrastructural examination of the pig retina revealed significant similarities to the human retina as reviewed, along with some new findings. The translation of scientific findings into actionable technologies for prevention and intervention requires suitable alternate models, and pigs may play an integral role by providing basic data for various researchers.

The Lanyu pig, a genetically unique miniature breed native to Taiwan, represents a valuable yet under-characterised large-animal model in biomedical research. Here, we present a detailed magnetic resonance imaging (MRI) and computed tomography (CT)-based anatomical atlas of male and female Lanyu pigs at 5–6 months of age. MRI effectively visualised brain, reproductive and abdominal structures, with T1-weighted images providing sharp anatomical boundaries and T2-weighted images enhancing cerebrospinal fluid and soft-tissue contrast. CT provided high-resolution visualisation of skeletal and cardiovascular anatomy, including vascular imaging and 3D reconstructions. Quantitative MRI analyses revealed sex-specific differences in brain and cerebellar morphology, with females showing smaller brain, cerebellar and hemisphere widths but greater cerebellar length compared to males. Long bone measurements exhibited significant age × sex-dependent interactions, with females demonstrating earlier skeletal elongation and males showing a delayed growth surge. Myocardial thickness, however, displayed sex-specific patterns independent of age, with thicker left ventricular walls and interventricular septa in males. Comparative morphometric data from other miniature pig breeds highlight the distinctive developmental profile of Lanyu pigs and underscore their potential as a complementary model. The integration of surface scanning with vascular CT further extends applications to surgical planning and comparative vascular analysis. Beyond its descriptive value, this open-access dataset provides a reusable anatomical resource that supports functional anatomical interpretation, stereotactic procedures and ethical animal use under the 3Rs framework. Collectively, this atlas fills a critical gap in swine anatomy and supports the translational value of Lanyu pigs in biomedical and surgical studies.

The osseous tentorium cerebelli attaches to the inner surface of the skull and separates the cerebrum from the cerebellum, thereby dividing the cranial cavity into the rostral and caudal cranial fossae. The transverse sinus canal/groove, located near the attachment margin of the tentorium cerebelli, houses the transverse venous sinus. During surgical procedures, it is essential to understand the anatomical position of the osseous tentorium cerebelli and transverse venous sinus using the surface structure of the skull as a landmark. This study compared the positional variation of the attachment site of the osseous tentorium cerebelli and transverse sinus canal/groove relative to the external landmarks of the skull, specifically the external occipital protuberance and nuchal crest in small dogs. We analysed computerised tomography data from 23 client-owned dogs of four small breeds without brain or skull lesions. Using sagittal plane images from computed tomography (CT), the osseous tentorium cerebelli deviation distance (OTCDD) and the transverse sinus canal or groove deviation distance (TSCGDD) from external landmarks were measured. Both OTCDD and TSCGDD exhibited interindividual variation. In the interbreed comparison, the OTCDD was significantly greater in Chihuahuas than in Toy Poodles and Miniature Dachshunds. A strong correlation was observed between OTCDD and TSCGDD. This study demonstrated both interindividual and interbreed diversity in the anatomical positioning of the osseous tentorium cerebelli and transverse sinus canal/groove. Nevertheless, these structures consistently maintained a close spatial relationship. The findings contribute to a more detailed anatomical understanding of the skull in small-breed dogs and may assist in optimising craniectomy procedures.