RESUMO
Magnetic resonance imaging (MRI) identified a paramagnetic substance in the hyaline cartilage of the hips and knees in a patient with ochronosis. Chemical studies characterized the paramagnetic agent as melanin. The free radicals contained in melanin were shown to initiate cytotoxicity. The loss of cartilage in ochronotic arthropathy now can be explained at the electron level using the superoxide theory of oxygen toxicity. Inappropriate metabolism of oxygen also may explain early cartilage degeneration in hemochromatosis, hemosiderosis, and Wilson's disease.
Assuntos
Cartilagem Articular/patologia , Artropatias/etiologia , Magnetismo/efeitos adversos , Melaninas/efeitos adversos , Ocronose/etiologia , Cartilagem Articular/análise , Feminino , Radicais Livres/efeitos adversos , Articulação do Quadril/análise , Articulação do Quadril/patologia , Humanos , Artropatias/diagnóstico , Articulação do Joelho/análise , Articulação do Joelho/patologia , Imageamento por Ressonância Magnética , Masculino , Melaninas/análise , Pessoa de Meia-Idade , Ocronose/diagnóstico , Coluna Vertebral/análise , Coluna Vertebral/patologiaRESUMO
BACKGROUND: Though it is rarely reported, decompression sickness (DCS) is an expected risk for U-2 aviators. The potential for chronic sequelae of untreated DCS in this population has never been addressed. METHODS: After conducting a preliminary survey at an active-duty U-2 squadron, a cohort of 416 U-2 pilots (active-duty and retired) were mailed two sequential anonymous surveys to assess demographic data, career prevalence of DCS symptoms, and overall health status with an emphasis on chronic musculoskeletal problems. RESULTS: The response rate for each mail-in survey was over 60%. During their career, 75.5% of pilots experienced DCS symptoms such as joint pain, skin manifestations, and/or various neurological problems. Symptoms generally started during flight and resolved upon descent. Many pilots voluntarily increased their oxygen prebreathing time, or inflated the pressure suit during flight to prevent or treat symptoms. At some point in their career 12.7% of those experiencing symptoms either altered the flight profile or aborted a mission as a result. The association of past DCS with current arthritic problems was not statistically significant. CONCLUSIONS: The career prevalence of DCS symptoms in U-2 pilots is higher than previously reported, and these symptoms sometimes affect mission completion. We found no evidence that chronic musculoskeletal sequelae (e.g., arthritis or dysbaric osteonecrosis) are causally associated with DCS in this population.