RESUMO
In this study, we investigated the efficacy and safety of the recently developed modifiable bioabsorbable plates and screws, which are made of PLGA [poly(lactic-co-glycolic acids)]. An in vitro extract test and a mammalian erythrocyte micronucleus test revealed that neither cytotoxicity nor genotoxicity was observed with the plates and screws tested in this study. An in vivo mandible fracture model in rabbit was introduced to evaluate the in vivo efficacy and of the PLGA-based plates and screws. At 4, 6, 8, and 10 weeks after implantation, tissue specimens were taken from the implanted sites of the rabbits and a histologic analysis was performed for each of the specimens. After 4 weeks, the plate was covered by connective tissues and severe chronic active inflammation in soft tissue was observed. After 6 weeks, the inflammation decreased and some of the specimens exhibited new bone formation around the periosteum. After 8 and 10 weeks, new bone formation was observed with all samples, where almost no severe inflammation was involved, implying the healing of the fracture. Given these, it can be suggested that the biodegradable plate and screw system that we evaluated in this study is effective for treatment of mandible fracture, one of the regions under a high load-bearing condition. The adjustment process and the long-term follow-up study are in progress for clinical application of the plate and screw system introduced in this study.
Assuntos
Implantes Absorvíveis , Materiais Biocompatíveis/uso terapêutico , Placas Ósseas , Parafusos Ósseos , Fixação Interna de Fraturas/instrumentação , Ácido Láctico , Fraturas Mandibulares/cirurgia , Ácido Poliglicólico , Animais , Modelos Animais de Doenças , Seguimentos , Fixação Interna de Fraturas/métodos , Copolímero de Ácido Poliláctico e Ácido Poliglicólico , CoelhosRESUMO
The WAVE-associated Rac GAP, WRP, is thought to regulate key aspects of synapse development and function and may be linked to mental retardation in humans. WRP contains a newly described inverse F-BAR (IF-BAR) domain of unknown function. Our studies show that this domain senses/facilitates outward protrusions analogous to filopodia and that the molecular basis for this is likely explained by a convex lipid-binding surface on the WRP IF-BAR domain. In dendrites the IF-BAR domain of WRP forms a bud on the shaft from which precursors to spines emerge. Loss of WRP in vivo and in vitro results in reduced density of spines. In vivo this is primarily a loss of mushroom-shaped spines. Developmentally, WRP function is critical at the onset of spinogenesis, when dendritic filopodia are prevalent. Finally, because WRP is implicated in mental retardation, behaviors of WRP heterozygous and null mice have been evaluated. Results from these studies confirm that loss of WRP is linked to impaired learning and memory.
Assuntos
Espinhas Dendríticas/fisiologia , Proteínas Ativadoras de GTPase/química , Proteínas Ativadoras de GTPase/metabolismo , Transtornos da Memória/metabolismo , Neurônios/ultraestrutura , Domínios e Motivos de Interação entre Proteínas/fisiologia , Animais , Animais Recém-Nascidos , Aprendizagem da Esquiva , Células Cultivadas , Chlorocebus aethiops , Espinhas Dendríticas/ultraestrutura , Modelos Animais de Doenças , Eletrochoque/métodos , Proteínas Ativadoras de GTPase/deficiência , Proteínas de Fluorescência Verde/genética , Hipocampo/citologia , Humanos , Metabolismo dos Lipídeos/genética , Lipossomos/metabolismo , Aprendizagem em Labirinto , Transtornos da Memória/genética , Camundongos , Camundongos Knockout , Microscopia Eletrônica de Varredura/métodos , Modelos Químicos , Neurônios/metabolismo , Testes Neuropsicológicos , Fosfatidilinositóis/metabolismo , Domínios e Motivos de Interação entre Proteínas/genética , Sensação/genéticaRESUMO
Mohs micrographic surgery of the lower eyelid poses a risk of ectropion. Even though the lower eyelid is a very frequent location for basal cell carcinoma, prevention techniques for ectropion after Mohs micrographic surgery have rarely been introduced. After Mohs micrographic surgery of the lower eyelid, the authors applied a barbed suture suspension technique for the prevention of lower eyelid ectropion. Following primary wound closure, barbed sutures were prepared by cutting one side of a 4-0 Prolene suture and applied around the lower eyelid. Sutures were maintained for 7 days and then removed. Evaluation 10 weeks after surgery found that ectropion had been minimized or prevented entirely.