Comparative MRI analysis of the forebrain of three sauropsida models.

The study of the brain by magnetic resonance imaging (MRI) allows to obtain detailed anatomical images, useful to describe specific encephalic structures and to analyze possible variabilities. It is widely used in clinical practice and is becoming increasingly used in veterinary medicine, even in exotic animals; however, despite its potential, its use in comparative neuroanatomy studies is still incipient. It is a technology that in recent years has significantly improved anatomical resolution, together with the fact that it is non-invasive and allows for systematic comparative analysis. All this makes it particularly interesting and useful in evolutionary neuroscience studies, since it allows for the analysis and comparison of brains of rare or otherwise inaccessible species. In the present study, we have analyzed the prosencephalon of three representative sauropsid species, the turtle Trachemys scripta (order Testudine), the lizard Pogona vitticeps (order Squamata) and the snake Python regius (order Squamata) by MRI. In addition, we used MRI sections to analyze the total brain volume and ventricular system of these species, employing volumetric and chemometric analyses together. The raw MRI data of the sauropsida models analyzed in the present study are available for viewing and downloading and have allowed us to produce an atlas of the forebrain of each of the species analyzed, with the main brain regions. In addition, our volumetric data showed that the three groups presented clear differences in terms of total and ventricular brain volumes, particularly the turtles, which in all cases presented distinctive characteristics compared to the lizards and snakes.

Distinct vascular zones in the canine prostate.

The vascular bed of canine prostate was studied and detailed distinct vascular zones were visualized on corrosion casts by scanning electron microscopy. This study was performed because of scarce information about the zonal vascularization of the prostate gland in dogs. There are no studies for three-dimensional microvascular distribution of the capsular vessels and the capsular microvascular trabeculae. SEM (vascular corrosion casting method) was used to show 3D angioarchitecture of the prostate gland. The lobules on the dorsal and lateral surface of the gland were numerous but small. Their small size is probably due to the abundant blood supply in the region. Few but large ventral lobules were observed. Three prostatic zones were clearly defined: capsular, parenchyma, and urethral. The diameter of the venous blood vessel compared to arterial vessels of the capsule was smaller. Two types of arteries were observed in trabeculae: direct and branched. The direct arteries were straight, with only a few branches. The branched arteries contained many bifurcations, with the vessel's diameter decreasing gradually. The trabeculae capillary network formed loops, with frequent sphincter-like constrictions and pouch-like protuberances.

Effect of anticoagulation and lavage prior to casting of postmortem material with Mercox and Batson 17.

In this study we compare the quality of vascular casts, obtained from organs of several animal species from different sources and sacrificed under different conditions. Organs from healthy animals were injected with two different polymers such as Mercox and Batson No. 17. When the specimens were observed under a scanning electron microscope structural elements such as endothelial nuclear impressions on vessels and capillaries, endothelial cell borders, venous valves, imprints of smooth muscle cells and intra-arterial cushions were identified. Organs excised post mortem from large animals can be used for microvascular corrosion casting studies with optimal results.

Microvasculature of the gastric mucosa in dogs.

A corrosion casting technique was used to study differences in the microvascular architecture of the pars cardiaca, the fundus ventriculi, the corpus ventriculi and the pars pylorica of the canine gastric mucosa. This technique revealed an unusual arrangement of the microvascular architecture in the nonglandular region surrounding the esophageal opening. Capillaries run tortuously along the mucosal surface parallel to the long axis of the esophagus, and some capillaries form a polygonal network that extends around the seromucous glands. In contrast, the mucosal capillaries of the glandular regions of the stomach are arranged in a symmetric pattern associated with the gastric glands. There are also differences in the mucosal microvessels of the cardiac and fundic areas compared to the corpus and the antrum. In the cardiac and fundic regions, a sparse microvascular pattern was observed and fewer capillaries drained into a single venule. However, the vessels surrounding the gastric glands in the corpus and antral areas drained into venules perpendicular to the hexagonal arrangement of the capillaries.