The internal vertebral venous plexus (IVVP) is an extensive vascular network recently implicated in various human and canine spinal disorders. Nevertheless, little recent information is available regarding normal anatomy of canine IVVP and its role in acute spinal injuries. The objectives of the study were; (1) to describe the normal IVVP morphology in the canine cervical region using transverse anatomy sections and computed tomography (CT), (2) to develop a technique for CT examination of the IVVP in vivo, (3) to analyze the quantitative characteristics of the IVVP, and (4) to assess the effect of acute experimental spinal cord compression on IVVP morphology. In the first experiment, CT of the cervical vertebral canal was performed in 6, normal, adult mixed-breed dogs. After dogs were euthanized, a gelatin and iothalamate mixture was injected into the right external jugular vein. Cadavers were then frozen to â 8°C, sliced into transverse sections, and compared with CT images. Vascular components such as the IVVP, interarcuate veins, intervertebral veins, and vertebral veins were accurately depicted on CT images. In the second experiment, CT venography was performed using a biphasic IV injection of iodinated contrast medium. Dimensions of the IVVP and other vertebral canal components were calculated for the C3-C7 vertebral region. Sagittal diameters of the IVVP ranged from 0.6 mm to 3.2 mm. The IVVP area occupied 30.61% of the cervical vertebral epidural space area. When C3-C7 segments were considered as a group, IVVP area dimensions were significantly correlated (r > 0.7, p < 0.0001) with vertebral canal area and dural sac area. In the last experiment, acute spinal cord compression (ASCC) was induced and maintained for 10 minutes using an angioplasty balloon catheter device over the C3/4 vertebral region in 6 dogs. Dogs were evaluated prior to, during, and after compression using digital subtraction venography (DSV) and CT venography. Results showed that ASCC produced a significant change in diameter of the IVVP at the site of compression. This effect persisted during the post-compression period. In conclusion, findings indicate that CT venography and DSV accurately depict the IVVP in dogs, and that significant changes of the IVVP morphology occur under ASCC conditions. / Ph. D.

El uso de modelos animales constituye una herramienta esencial para investigar la etiología y patogenia de la diabetes, así como para desarrollar tratamientos efectivos: el transplante de islotes pancreáticos o ingeniería genética. El éxito de estas terapias depende en gran medida de la correcta elección de la vía de administración. Objetivos: 1.- Estudiar la anatomía e histología del páncreas porcino; 2.- Describir la anatomía seccional de la región pancreática mediante RM y secciones anatómicas plastinadas; 3.- Confirmar que las arterias pancreáticas terminales en el cerdo constituyen una ruta potencial para la administración selectiva mediante técnicas endovasculares mínimamente invasivas.Diseño de la investigación y métodos: Cerdos Large White jóvenes fueron examinados con RM y posteriormente sacrificados de forma humanitaria. Criosecciones transversales finas (2-3 mm) en las que se interesaba el páncreas fueron plastinadas mediante el método E-12 (Biodur®). 19 páncreas se procesaron para el estudio histológico. El análisis vascular de las ramas terminales del páncreas se realizó mediante la inyección de ocho cadáveres de cerdo con resina epoxy. En 20 cerdos vivos se llevaron a cabo angiografías superselectivas en ramas terminales.Resultados: El porcentaje y tamaño de los islotes de parénquima endocrino fueron mayores en el lóbulo derecho que en el resto del páncreas. Las secciones a nivel de la vértebra T15 interesaron las mayores áreas del páncreas, en concreto el lóbulo izquierdo. Una rama pancreática terminal de la arteria esplénica se presentó en todos los animales. Conclusión: se ha desarrollado un valioso abordaje mínimamente invasivo al páncreas porcino. Ello puede contribuir al ensayo de nuevas terapias para diabetes en este modelo animal. No obstante, nuevos estudios se hacen necesarios para poder evaluar la eficacia del abordaje referido en terapia para diabetes. / Animal models are essential tools for investigating the etiology and pathogenesis of diabetes and for the development of effective treatments: islet transplantation or genetic engineering. Successful of these new therapies will depend on the appropriate choice of the route of administration. Objectives: 1. Study the anatomy and histology of the porcine pancreas; 2. Describe the normal sectional anatomy of the pig pancreatic region by MRI and plastinated anatomic sections; 3. Confirm that the pancreatic terminal arteries in pigs are a potential route for the selective delivery of islet cells or gene products to the pancreas by minimally invasive endovascular techniques. Research design and methods: Large White juvenile pigs were examined by MRI and then euthanized according to human procedure. Thin transversal cryosections (2-3mm) containing the pancreas were plastinated by the E12 method (Biodur®). 19 pancreases were process for histology study. Anatomic vascular study of pancreatic terminal arteries was obtained by epoxy resin injection of eight pig cadavers. Super selective angiography in the pancreatic terminal branch was conducted in vivo in 20 pigs. Results: Frequency and size of endocrine parenchyma islets was higher in right lobe of the pancreas than in the rest of the pancreas. Sections at the level of vertebra T15 showed the highest areas of pancreas and were related with left lobe. A constant pancreatic terminal branch from the splenic artery was present in all animals. Conclusion: a valuable minimally invasive approach to the porcine pancreas has been developed. It may contribute to assay new diabetes therapies in swine models. Further studies are needed to examine the specific efficiency of this approach in diabetes therapies.

No description available.

abstract: The unique anatomical and functional properties of vasculature determine the susceptibility of the spinal cord to ischemia. The spinal cord vascular architecture is designed to withstand major ischemic events by compensating blood supply via important anastomotic channels. One of the important compensatory channels of the arterial basket of the conus medullaris (ABCM). ABCM consists of one or two arteries arising from the anterior spinal artery (ASA) and circumferentially connecting the ASA and the posterior spinal arteries. In addition to compensatory function, the arterial basket can be involved in arteriovenous fistulae and malformations of the conus. The morphometric anatomical analysis of the ABCM was performed with emphasis on vessel diameters and branching patterns. A significant ischemic event that overcomes vascular compensatory capacity causes spinal cord injury (SCI). For example, SCI complicating thoracoabdominal aortic aneurysm repair is associated with ischemic injury. The rate of this devastating complication has been decreased significantly by instituting physiological methods of protection. Traumatic spinal cord injury causes complex changes in spinal cord blood flow (SCBF), which are closely related to a severity of injury. Manipulating physiological parameters such as mean arterial pressure (MAP) and intrathecal pressure (ITP) may be beneficial for patients with a spinal cord injury. It was discovered in a pig model of SCI that the combination of MAP elevation and cerebrospinal fluid drainage (CSFD) significantly and sustainably improved SCBF and spinal cord perfusion pressure. In animal models of SCI, regeneration is usually evaluated histologically, requiring animal sacrifice. Thus, there is a need for a technique to detect changes in SCI noninvasively over time. The study was performed comparing manganese-enhanced magnetic resonance imaging (MEMRI) in hemisection and transection SCI rat models with diffusion tensor imaging (DTI) and histology. MEMERI ratio differed among transection and hemisection groups, correlating to a severity of SCI measured by fraction anisotropy and myelin load. MEMRI is a useful noninvasive tool to assess a degree of neuronal damage after SCI. / Dissertation/Thesis / Doctoral Dissertation Neuroscience 2016