RESUMEN
Chemical injury of the conjunctiva and cornea are true ocular emergencies and require immediate intervention. They can produce severe, extensive ocular damage, including limbal stem cell deficiency (LSCD), and lead to irreversible visual loss. LSCD can be treated surgically through autologous limbal stem cell transplantation (LSCT). Autologous LSCT can be performed through cultivated limbal epithelial transplantation (CLET) or by direct grafting of limbal epithelial cells through conjunctival-limbal autografting (CLAU) or simple limbal epithelial transplantation (SLET). In this review we provide an overview of each surgical approach. CLET allows for a implantation of a large graft in the recipient eye while preserving donor cells. Its success rate is higher with an increased number of transplanted stem cells; failures tend to occur within the first year. CLAU is performed by directly transplanting autologous limbal stem cells from the patient's healthy eye, reducing the risk of immune rejection. This constitutes a risk for the donor eye, as the removal of stem cells from the fellow eye may lead to LSCD in the donor eye. SLET consists of direct implantation of donor stem cells on an amniotic membrane, thus avoiding the need for ex-vivo expansion. Combinations of CLAU and SLET within a single procedure have also been successfully utilized. Autologous LCST is an effective technique for surgical management of unilateral LCSD. Depending on the patient history and status of the fellow eye, either CLET, CLAU or SLET (including the combination of mini-CLAU and SLET) can be used to restore long-term function and prevent visual impairment.
Asunto(s)
Quemaduras Químicas , Enfermedades de la Córnea , Trasplante de Córnea , Epitelio Corneal , Quemaduras Oculares , Limbo de la Córnea , Quemaduras Químicas/cirugía , Córnea , Enfermedades de la Córnea/cirugía , Trasplante de Córnea/métodos , Epitelio Corneal/cirugía , Quemaduras Oculares/inducido químicamente , Quemaduras Oculares/cirugía , Humanos , Limbo de la Córnea/cirugía , Trasplante de Células Madre/efectos adversos , Trasplante de Células Madre/métodos , Trasplante Autólogo , Trastornos de la Visión/cirugíaRESUMEN
The metal levels of arsenic, chromium, copper, lead, magnesium, manganese, selenium, vanadium, and zinc concentrations were determined in various body organs, viz., hepatopancreas, gills, gonad, gastric stomach, and muscle of the blue crab, Portunus pelagicus (Crustacea: Decapoda) to assess the bioaccumulation of metals associated with petroleum input a decade after the 1991 Gulf War oil spillage. Sample solutions prepared were analyzed using an atomic absorption spectrophotometry. High concentrations of Zn and Cu in the muscle and hepatopancreas tissues were a strong indicative of high exposure of P. pelagicus to these metals. However, muscle tissue had been found to accumulate the highest values for all metal speciations analyzed. Copper, zinc, and chromium in samples collected from Station II covering the Kuwait City area were often in excess of those present in Station I and III. Arsenic, lead, magnesium, manganese, selenium, and vanadium were greater in individuals obtained from Station I. A significant correlation was found to exist between Se and V in crab muscle with a surge in Se metal concentration, which was found to be inversely proportional to that of V metal concentration irrespective of the sex of the crab. The difference in patterns of metal occurrence and the significant increase in the Cu and Zn concentrations in various organs of the crab were largely associated with the 1991 Gulf War oil spill. Such results could be used as a baseline for the monitoring of the level of metals in marine organisms of future studies.