Bioingeniería
1. Characterization of the specie Caiman crocodilus within the Colombian Territory
Introduction
The Neotropical zone, which includes South and Central America, the Caribbean Islands, the Mexico lowlands, and southern Florida, is delimited by similarities in fauna and flora. Its tropical rainforest is the home of the most of the Alligatoridae family. The Neotropical Caiman genus is widely distributed through Mesoamerica, northern South America, and the Amazon basin. The Alligatoridae family consists of three genera: Alligator, Paleosuchus and Caiman. Poe (1966) considered the Melanosuchus as a synonym for Caiman. The classification of genus and species most widely accepted is King & Burke´s list. They divide the Caiman genus into three species: C. crocodilus, C. latirrostris, and C. yacare.
Colombia is one of the countries with one of the largest crocodilian diversity around the world. Four subspecies make up the caiman crocodilus specie: caiman crocodilus apaporiensis, caiman crocodilus chiapasius, caiman crocodilus crocodilus, and caiman crocodilus fuscus. Despite the huge geographical dispersion of the C. crocodilus specie, differences between the four subspecies have been established based not only on DNA , but also on morphologic analysis , thus has been reported that Colombia is the unique country that has presence of the four recognized subspecies of Caiman Crocodilus specie. Geographical distribution of the Caiman crocodilus with the presence of four subspecies within the Colombian territory. (A) as suggested by Velasco and Ayarzaguena, (B) as proposed by Busak and Pandya.
Hypothesis to be tested
The proposed research seeks to answer four fundamental questions:
(I) How are the population structure, abundance, and geographical distribution of the caiman crocodilus within the Colombian territory?
It is necessary studies in population structure, abundance, distribution of caiman crocodilus within the Colombian territory to approach a better global vision of the actual state. Also, more studies in taxonomy field are needed due to the misconception and lack of clarity in the alleged subspecies of the caiman crocodilus that could be found in Colombia.
(II) How are the phylogeographical patterns of caiman crocodilus presented within the Colombian territory?
Mitochondrial DNA (mDNA) provides the most efficient marker available for characterizing the geographic population structure of a species for which other genetic markers have not yet been developed. Although mDNA provides only a single 3evolutionary genetic marker that may not be representative of the variability present across the nuclear genome, and though independent markers may give contrasting phylogenetic signal, mDNA is particularly useful in identifying and delineating distinct evolutionary
lineages and inferring their relationships.
(III) How are the biomechanical differences among the skulls of four caiman species: C. c. Crocodilous, C. c. Fuscus, C. c. Chiapasius and C. c. Apaporiensis?
The biomechanical analysis of skulls will not only establishes both the habitat and feeding behavior, but also will facilitates to know the evolutionary changes in the species and its relation to other species.
(IV) How are the differences in skull morphology among four subspecies of the caiman crocodile?
Head size, relationship between inter-ocular distance, and the distance from the infra orbital bridge to the snout will be performed on specimens from each subspecie from the caiman crocodilus.
Contacto
Uriel Zapata, Ph.D.
uzapata@eafit.edu.co
http://www.ncbi.nlm.nih.gov/pubmed/?term=Zapata+U%5BAuthor%5D
Teléfono (+574) 2619367
Departamento de Ingeniería Mecánica
Universidad Eafit
Carrera 49 # 7sur - 50
Medellín, Colombia, South America
2. Biomechanical effects of recombinant human bone morphogenetic protein-2 on absorbable collagen sponge in the reconstruction of alveolar cleft defects in rats
Introduction
Clefts of the lip and palate are craniofacial birth defects in humans caused by an anomaly of midfacial skeletal growth during embryonic developmen. An alveolar cleft is an unnatural opening of the palatal arch produced by the failure of fusion between the maxillary and medial nasal procedures, which involves both soft and hard tissues. This congenital deformity affects approximately 1 in 700 newborn children, affecting basic functions as breathing, speech, hearing, feeding and socialization.
Bone substitutes as mineralized human allograft, and synthetic allografts have been widely used for alveolar bone grafting. Bovine xenografts have also been utilized in minor scale. However, both allogeneic bone grafts and xenograft bone substitutes have reported problems of infections, disease transmission from the donor, and rejection due to differences in MHC molecules.
Another option to repair the cleft palate defect is by using engineered designed scaffold matrices which can be implanted alone to induce osteoconduction, or it may serve as a carrier for bony cells to enhance osteogenesis.
Natural polymers, which are derived from plant or animal sources as collagen, have been used in bone tissue engineering applications of the cleft palate defect. Complementarily, growth factors can be added in to the scaffold in order to enhance osteogenesis, angiogenesis, and chondrogenesis. However, only recombinant human BMP-2 (rhBMP-2) has been approved by the US Food and Drug Administration (FDA) for clinical use in human.
Hypothesis to be tested:
This research seeks to answer three essential questions:
(I) Is there any mechanical advantage in the new-formed alveolar bone after a single addition of rhBMP-2?
Several studies have compared clinically the effect of BMPs combined with scaffolds in humans, and a study has reported descriptive results in dogs. However, in our knowledge, there are no reports of the incidence of BMPs combined with scaffolds on the microstructure, biomechanics, and blood vessels formation of the regenerate tissue of the cleft palate.
(II) Is there any biomechanical effect for the progressive presence of rhBMP-2 within the palatal defect?
Because 92 % of the initial dose of BMP is lost during the first two weeks after its initial application, it is interesting to know if a progressive delivery of rhBMP-2 would affect its osteogenic efficacy. Although combinations of the BMPs with gelatin foams or collagen has increase the retention up to 55% , in our knowledge, no study has investigated whether successive applications of rhBMP-2 over the time would affects the osteogenic processes of the regenerate tissue at the alveolar cleft defect.
(III) Is possible to maintain the concentration of rhBMP-2 within the palatal defect by using barrier membranes?
A membrane barrier is a biocompatible system that creates an isolate space to romote bone healing processes. The main goal of a barrier membrane for the reconstruction of bone defects is to create a protected space for the ingrowth of fibroblasts, excluding inhibiting factors, and preserving growth factors. However, the presence of barrier membranes combined with scaffolds has not been tested in the correction of cleft palate.
Contacto
Uriel Zapata, Ph.D.
uzapata@eafit.edu.co
http://www.ncbi.nlm.nih.gov/pubmed/?term=Zapata+U%5BAuthor%5D
Teléfono (+574) 2619367
Departamento de Ingeniería Mecánica
Universidad Eafit
Carrera 49 # 7sur - 50
Medellín, Colombia, South America