Asunto(s)
Pustulosis Exantematosa Generalizada Aguda/etiología , Medios de Contraste/efectos adversos , Yohexol/análogos & derivados , Yopamidol/análogos & derivados , Pustulosis Exantematosa Generalizada Aguda/patología , Pustulosis Exantematosa Generalizada Aguda/prevención & control , Corticoesteroides/uso terapéutico , Anciano de 80 o más Años , Reacciones Cruzadas , Humanos , Yohexol/efectos adversos , Yopamidol/efectos adversos , Masculino , Pruebas del Parche , Premedicación , Índice de Severidad de la EnfermedadRESUMEN
Seawater is constantly circulating through oceanic basement as a low-temperature hydrothermal fluid (<150 degrees C). In cases when ultramafic rocks are exposed to the fluids, for instance during the initial phase of subduction, ferromagnesian minerals are altered in contact with the water, leading to high pH and formation of secondary magnesium hydroxide, among other--brucite, that may scavenge borate and phosphate from seawater. The high pH may promote abiotic formation of pentoses, particularly ribose. Pentoses are stabilized by borate, since cyclic pentoses form a less reactive complex with borate. Analyses have shown that borate occupies the 2' and 3' positions of ribose, thus leaving the 5' position available for reactions like phosphorylation. The purine coding elements (adenine, in particular) of RNA may be formed in the same general hydrothermal environments of the seafloor.