RESUMEN
A novel type of temperature-sensitive dendrimer was synthesized using one-step terminal modification of polyamidoamine dendrimers (PAMAM) with various alkoxy diethylene glycols such as methoxy diethylene glycol, ethoxy diethylene glycol, and propoxy diethylene glycol. The obtained dendrimers exhibited tunable lower critical solution temperature (LCST), depending on PAMAM generation and terminal alkoxy groups. These dendrimers were shown to be taken up by HeLa cells through endocytosis and were trapped in intracellular compartments such as endosomes and lysosomes. Cellular uptake of the dendrimers was enhanced by increasing their incubation temperature above the LCST. In addition, the in vitro cytotoxicity of temperature-sensitive dendrimers at incubation temperatures below and above LCST was much lower than that of their parent PAMAM dendrimers. Results indicate that the dendrimers with oxyethylene unit-enriched surface might be promising to construct intelligent drug delivery systems.
Asunto(s)
Materiales Biocompatibles/química , Dendrímeros/química , Polietilenglicoles/química , Materiales Biocompatibles/metabolismo , Materiales Biocompatibles/toxicidad , Supervivencia Celular/efectos de los fármacos , Dendrímeros/metabolismo , Dendrímeros/toxicidad , Sistemas de Liberación de Medicamentos , Endocitosis , Células HeLa , Humanos , Polietilenglicoles/metabolismo , Polietilenglicoles/toxicidad , TemperaturaRESUMEN
This study investigated the association of craniofacial and glenoid fossa shapes and temporomandibular joint (TMJ) pathology in 39 orthodontic patients with signs and symptoms of TMJ disorders, using helical CT scans. Cephalometric measurements showed that 21 subjects with bilateral condylar bone change (BBC) had significantly smaller SNB angles, ramus heights and S-Ar/N-Ba ratios, as well as larger mandibular plane angles and lower anterior facial height than the 18 subjects with no condylar bone change (NBC). The average posterior slope of the left and right articular eminence in their central and lateral sections was significantly steeper in NBC than in BBC. Condylar bone change might, therefore, not only be related to the morphology of the mandible, but also of the glenoid fossa and cranial base. This appears to reflect adaptive changes in the condyle, articular eminence and cranial base in response to changes in loading.