Perceived physical and emotional trauma as precipitating events in fibromyalgia. Associations with health care seeking and disability status but not pain severity

The spectrophotometry and photofluorescence techniques were used in the studies on photochemical transformations of lactate dehydrogenase exposed to UV irradiation with a dose of 2.25 kJ/m2, in the native state and in the presence of exogenous modifiers: sodium azide, beta-carotene, histidine, D-mannitol, and tret-butanol. It was shown that UV irradiation of the mixtures of lactate dehydrogenase with sodium azide, beta-carotene, and histidine results in restoration (by 99, 65, and 63%, respectively) of the level of catalytic activity of the enzyme as compared to that observed after irradiating it in the absence of the protectors. The protective effect provided by mannitol during UV irradiation of the lactate dehydrogenase was 23%. Thus, it was shown that active oxygen species--singlet molecular oxygen and hydroxyl radical--make significant contributions to photomodification of lactate dehydrogenase.