ABSTRACT
BACKGROUND: There is widespread controversy regarding the potential of human neural stem cells and human mesenchymal stem cells (hMSCs) to form cell types outside of their normal developmental lineage. A greater understanding of the differentiation potential and bias of these stem cell types would allow researchers to select the cell type that best suits the research or clinical need at hand. MATERIALS & METHODS: We used identical in vitro protocols to quantitatively compare the potential of human embryonic stem cells, human neural stem cells and hMSCs to differentiate into specific ectodermal or mesodermal lineages. RESULTS: Our findings demonstrate that human embryonic stem cells and human neural stem cells have the ability to differentiate into high purity neuronal progenitor or oligodendrocyte progenitor cultures. By contrast, hMSCs generated exceedingly limited numbers of neural lineages. Both human embryonic stem cells and hMSCs generated adipocytes and osteocytes when exposed to mesodermal differentiation conditions. CONCLUSION: These studies underscore the importance of distinguishing differentiation potential from differentiation bias, an important consideration in the development of cell replacement strategies.
Subject(s)
Embryonic Stem Cells/cytology , Mesenchymal Stem Cells/cytology , Neurons/cytology , Regenerative Medicine/methods , Stem Cells/cytology , Adipocytes/metabolism , Adult , Cell Differentiation , Cell Lineage , Female , Humans , Immunohistochemistry/methods , In Vitro Techniques , Male , Mesoderm/metabolism , Osteocytes/metabolismABSTRACT
Frequently, the first noticeable sign of an odontogenic myxoma is a slowly enlarging, painless expansion of the jaw. Spreading, loosening, and migration of teeth in the area commonly occur. In the early stages, the tumor is asymptomatic, and detection is made only by routine radiographs. Clinicians should be aware of the radiographic changes caused by this benign odontogenic tumor, and include it in their differential consideration of lesions presenting such changes in the jaws. A typical case of a fairly large odontogenic myxoma has been presented. The clinical, radiographic, and histological presentations have been discussed. The tumor was treated by en bloc resection with immediate bone and nerve reconstruction. The patient responded well to therapy and no tumors were found at the 1 year follow-up examination.
Subject(s)
Mandibular Neoplasms/diagnostic imaging , Odontogenic Tumors/diagnostic imaging , Adult , Humans , Male , Mandibular Neoplasms/pathology , Odontogenic Tumors/pathology , RadiographyABSTRACT
Two mongrel adult dogs were used in this study. The mandible was edentulated unilaterally and then augmented with porous tribasic calcium phosphate ceramic. To determine the effects of a denture over the augmented site, a unilateral distal-extension removable partial denture was constructed and inserted. At the end of the 6-month period, clinical evaluation revealed a healthy residual alveolar ridge tissue with no inflammatory reaction due to the implant. Histologic examination confirmed the clinical findings. There was no inflammation, bone and soft tissue grew into the pores, and no bone resorption occurred. It is concluded therefore that porous tribasic calcium phosphate ceramic is a potential material for residual alveolar ridge augmentation.
Subject(s)
Alveolar Process/physiology , Alveoloplasty , Biocompatible Materials , Ceramics , Dental Stress Analysis , Alveolar Process/anatomy & histology , Animals , Calcium Phosphates , Denture, Partial, Removable , Dogs , Osteogenesis , Pilot ProjectsABSTRACT
The results of a 5-year clinical study show that patients treated with complete maxillary dentures and mandibular overdentures demonstrate less vertical alveolar bone reduction than patients with complete maxillary and mandibular dentures.
Subject(s)
Alveolar Process , Bone Resorption/etiology , Denture, Complete/adverse effects , Denture, Overlay/adverse effects , Aged , Alveolar Process/pathology , Bone Resorption/pathology , Denture, Complete, Lower , Denture, Complete, Upper , Humans , Male , Mandible/pathology , Maxilla/pathology , Middle Aged , Proprioception , Time Factors , Tooth/physiologyABSTRACT
Tricalcium phosphate ceramic, with 50% porosity and 400 to 500 micrometer pore diameter, was used to augment the edentulous alveolar ridge of 10 adult mongrel dogs. The implants were evaluated histologically at different time intervals (7, 30, 90, 180, and 360 days). Preoperative and postoperative blood chemistry studies were also evaluated. The results showed that, other than for the expected acute nonspecific inflammatory response due to the surgery, the material was well tolerated by the tissues and was nontoxic. Bone and soft tissues grew into the pores, thereby creating an excellent biomechanical bond between the ceramic implant and surrounding structures. Preoperative and postoperative blood chemistry studies demonstrated no significant change.
