Degreasing and bleaching bones using light sources as a tool to increase the safety of teaching osteology at the University of Veterinary Sciences Brno.

The key part of creating bone material for teaching is degreasing and whitening it. However, the substances used are often dangerous and toxic. We tested and compared safer methods based on two physical variables. These are light and heat. The material for our study was 45 femurs from 23 adult domestic dogs (Canis lupus f. familiaris). The bones were divided into three groups of 15 pieces according to the method used to remove muscles and ligaments from their surface. Five femurs from each group were exposed to three different light sources for 28 days-sunlight, warm light from a classical incandescent light bulb and cold light by a LED bulb. At regular intervals, the change in the colour of the bone surface and the amount of fat loss from the medullary cavity was also monitored. The best degreasing and bleaching results were achieved in macerated bones exposed to sunlight. They achieved the required condition as early as 21 days after the start of sun exposure. The biggest problem was haemoglobin, which permeated through the Haversian canals and discoloured the bone tissue. The results showed that the use of light and heat is a suitable and safe alternative to chemical methods of degreasing and bleaching bones. The disadvantage is the length of time, especially for native material.

X-ray microtomography imaging of craniofacial hard tissues in selected reptile species with different types of dentition.

BACKGROUND: Reptiles exhibit a large heterogeneity in teeth morphology. The main variability comprises the different tooth shape, the type of tooth attachment to the underlying bone, or the ability to replace the teeth. FINDINGS: Here, we provide full datasets of microtomography scans and 3D models of reptilian dentitions and skulls. We selected representative species for each of 9 reptilian families on the basis of their characteristic dental features. Because there are ≥4 different types of tooth-bone attachments, ranging from the mammalian-like thecodont attachment found in crocodilians to the simple acrodont implantation observed in some lizards, we aimed to evaluate species with different types of tooth-bone attachments. Moreover, another interesting feature varying in reptilian species is the complexity of tooth shape or the number of tooth generations, which can be associated with the type of tooth attachment to the jawbone. Therefore, selected model species also include animals with distinct tooth morphology along the jaw or different number of tooth generations. The development of tooth attachment and relationship of the tooth to the jaw can be further analysed in detail on a large collection of pre-hatching stages of chameleon. Next, we introduce different possibilities for how these datasets can be further used to study tooth-bone relationships or tooth morphology in 3D space. Moreover, these datasets can be valuable for additional morphological and morphometric analyses of reptilian skulls or their individually segmented skeletal elements. CONCLUSIONS: Our collection of microcomputed tomography scans can bring new insight into dental or skeletal research. The broad selection of reptilian species, together with their unique dental features and high quality of these scans including complete series of developmental stages of our model species and provide large opportunities for their reuse. Scans can be further used for virtual reality, 3D printing, or in education.

Newly described anatomical opening on forelimb tendon in the artiodactyls and its relation to knee clicks.

To understand which morphological/anatomical parts may be responsible in artiodactyl ungulates for the clicking sound made when moving, this research focuses on the forelimb tendon apparatus where an undescribed opening in the fibrous cuff (manica flexoria), called hereafter for its shape as an "oval window" in the manica flexoria (OWMF), was detected. This oval window was found in 24 of the 25 species of four families (Camelidae, Giraffidae, Cervidae, and Bovidae) evaluated; the exception being in Bos taurus taurus (Domestic cattle). The length and width of the OWMF enabled correct species discrimination between the majority of species, but remained conservative intraspecifically, as it did not differ between the left and right side of the forelimb, third and fourth digits, or between sexes. When evaluating the shape of OWMF in individual species, and measuring its length and width, 18 out of the 24 species investigated had this window as an oval shape, the remaining 25% of species exhibited more oval-oblong shapes with either proximal or distal asymmetry. The function of the OWMF in the thoracic autopodium of most ruminant even-toed ungulates is not yet fully understood. Its most likely function is to help balance the pressure inside the ligament cuff and reduce the friction of the touching surfaces of the muscle tendons-thus facilitating the movement of the digits when walking. None of the absolute or relative OWMF parameters fit exclusively with the occurrence and distribution of knee-clicks produced by some bovids and cervids during movement, so the mechanism responsible for this sound remains cryptic from the present anatomical perspective.

Differences in the anatomy of the lower respiratory tract in selected species of the order Testudines.

The lower airways of turtles consist of the larynx, trachea and bronchi. Due to incomplete information about the anatomical structure of the lower respiratory tract in turtles, we decided to explore this topic more deeply. The material for this study included 95 turtle cadavers. Terrestrial tortoises were represented by 63 individuals from 8 species, aquatic and semi-aquatic turtles by 32 individuals from 11 species. The sex ratio was 54 females to 41 males. In addition to the anatomical autopsies and assessments of the macroscopic structures, numerous measurements were performed. The length, width and height of the larynx and trachea, and the length of the bronchi were measured. We found clinical significance in two parameters. The first one is the formation of the rima glottidis, which is significantly shorter and narrower in the aquatic turtles than in the terrestrial tortoises. It follows that for these species, we should use a smaller diameter of endotracheal cannula for intubation. The second parameter is a very short trachea in tortoises of the genus Testudo. The length of the trachea is only a few centimetres, which significantly increases the risk of intubation into one bronchus only.

Polarized Sonic Hedgehog Protein Localization and a Shift in the Expression of Region-Specific Molecules Is Associated With the Secondary Palate Development in the Veiled Chameleon.

Secondary palate development is characterized by the formation of two palatal shelves on the maxillary prominences, which fuse in the midline in mammalian embryos. However, in reptilian species, such as turtles, crocodilians, and lizards, the palatal shelves of the secondary palate develop to a variable extent and morphology. While in most Squamates, the palate is widely open, crocodilians develop a fully closed secondary palate. Here, we analyzed developmental processes that underlie secondary palate formation in chameleons, where large palatal shelves extend horizontally toward the midline. The growth of the palatal shelves continued during post-hatching stages and closure of the secondary palate can be observed in several adult animals. The massive proliferation of a multilayered oral epithelium and mesenchymal cells in the dorsal part of the palatal shelves underlined the initiation of their horizontal outgrowth, and was decreased later in development. The polarized cellular localization of primary cilia and Sonic hedgehog protein was associated with horizontal growth of the palatal shelves. Moreover, the development of large palatal shelves, supported by the pterygoid and palatine bones, was coupled with the shift in Meox2, Msx1, and Pax9 gene expression along the rostro-caudal axis. In conclusion, our results revealed distinctive developmental processes that contribute to the expansion and closure of the secondary palate in chameleons and highlighted divergences in palate formation across amniote species.

Cattle stunning with a penetrative captive bolt device: A review.

The captive bolt device has been used for stunning cattle at abattoirs for more than 100 years and is now one of the stunning devices used most widely. The aim of this review article was to assess the effects that are decisive during cattle slaughter on the quality of stunning with the use of a captive bolt stunning device. The basis of effective stunning is the use of a suitable type of device, with the speed of the bolt and the kinetic energy corresponding to the anatomical parameters of the slaughtered animal. The importance of the regular cleaning and maintenance of stunning devices and monitoring of the effectiveness of stunning goes without saying. The immediate loss of sensibility in the animal must occur after the first shot. The effectiveness of the stunning process can be quantified by regular monitoring of the behavior of animals after stunning with an emphasis on the loss of reflexes (corneal reflex, regular breathing, attempts to regain physiological posture) and checks on the shot location on the skulls of slaughtered animals.

Facial pillars in dogs: an anatomical study.

This study describes the facial pillar system in dolichocephalic and brachycephalic breeds of dogs, and highlights its differences. Knowledge of facial pillar system anatomy is imperative to carry out successful fracture repair. The aim of our study was to describe the pillar system of the facial skeleton in dogs, and compare different shapes of dog skulls using native skulls, radiographs and computed tomography (CT). The heads of brachycephalic and dolichocephalic dogs were investigated following a maceration process using trans-illumination, radiography and CT. Ground sections were created from bones of the facial skeleton for investigation of osteon directions. This study has revealed that the facial skeleton of the dog has numerous sinuses supported by vertically and horizontally oriented bone pillars. These pillars can be divided into five principal regions in dolichocephalic skulls and six principal regions in brachycephalic skulls. Radiographic imaging of both the brachiocephalic and dolichocephalic skulls was not capable of discerning bone pillars. Computed tomography transverse and horizontal section images discerned all pillars observed in the illuminated skulls.