[Oxidative stress: a review on metabolic signaling in type 1 diabetes]. / Estresse oxidativo: revisão da sinalização metabólica no diabetes tipo 1.

Diabetic complications appear to be multifactorial process. The biochemical and pathological mechanisms are associated with chronic hyperglycemia of diabetes and the increased oxidative stress which has been postulated to play a central role in these disorders. Accumulating evidence suggests that oxidative cell injury caused by free radicals contributes to the development of type 1 diabetes (DM1) complications and decreased efficiency of antioxidant defenses (both enzymatic and nonenzymatic) seems to correlate with the severity of pathological tissue changes in DM1. In this review, we report as oxidative stress may exert deleterious effects in diabetes, as well as address current strategies in study to down-regulating vascular injury.

Estresse oxidativo: revisão da sinalização metabólica no diabetes tipo 1 / Oxidative stress: a review on metabolic signaling in type 1 diabetes

O diabetes melito e suas complicações apresentam origem multifatorial. Mecanismos bioquímicos e patológicos estão associados com hiperglicemia crônica no diabetes e o aumento do estresse oxidativo tem sido postulado com papel central nestas desordens. Evidências sugerem que a lesão celular oxidativa causada pelos radicais livres contribuem para o desenvolvimento das complicações no diabetes tipo 1 (DM1) e a diminuição das defesas antioxidantes (enzimáticas e não-enzimáticas) parecem correlacionar-se com a gravidade das alterações patológicas no DM1. Nesta revisão, relata-se como o estresse oxidativo pode exercer efeitos deletérios no diabetes e são apresentadas as opções terapêuticas em estudo para modulação da injúria vascular.

Diabetic complications appear to be multifactorial process. The biochemical and pathological mechanisms are associated with chronic hyperglycemia of diabetes and the increased oxidative stress which has been postulated to play a central role in these disorders. Accumulating evidence suggests that oxidative cell injury caused by free radicals contributes to the development of type 1 diabetes (DM1) complications and decreased efficiency of antioxidant defenses (both enzymatic and nonenzymatic) seems to correlate with the severity of pathological tissue changes in DM1. In this review, we report as oxidative stress may exert deleterious effects in diabetes, as well as address current strategies in study to down-regulating vascular injury.

Oxidizing and reducing responses in type 1 diabetic patients determined up to 5 years after the clinical onset of the disease.

Oxidative stress has been suggested to be the mediator of hyperglycaemia-induced diabetic complications. For this study we asked whether a significant imbalance between oxidizing and plasmatic reducing responses could be observed in DM1 patients receiving intensive therapy up to 5 years following the clinical onset of the disease. A total of 16 type 1 diabetic patients (DM1) without complications and 13 non-diabetic subjects were enrolled. Clinical and biochemical parameters were compared in the two populations studied. Moreover, reactive oxygen species (ROS) generation by granulocytes and the total plasma antioxidant status were simultaneously evaluated. Granulocytes-ROS derived and plasma antioxidant status were determined by chemiluminescence assay and tetrazolium dye reduction, respectively. Type 1 diabetic patients were receiving intensive therapy by multiple daily injections. In comparison with healthy individuals, DM1 patients exhibited an increase in ROS generation whilst plasma antioxidant status was unaltered and appeared to be sufficient to prevent the onset of typical oxidative stress. The clinical characteristics and the remaining biochemical parameters studied were similar for the two groups, except for a significantly decreased plasmatic level of uric acid in DM1 patients. This study suggests that the absence of complications in DM1 patients up to 5 years after onset of the disease may be associated with the oxidizing and reducing balance which need to be maintained in order to prevent or delay the onset of oxidative stress. The effective diabetic control involves evaluation of the oxidizing/antioxidant balance besides glycaemic control.

Paraganglioma funcionante do pescoço / Neck functioning paraganglioma

Paragangliomas funcionantes sao tumores raros, produtores de catecolaminas que se originam da crista neural. Apresentamos o caso de um paciente de 11 anos com quadro de hipertensao arterial grave e massa em regiao cervical direita. Apresentou aumento das catecolaminas e metabólitos urinários: epinefrina, 97,8 mug/24hs (Valor de Referência (VR)= 0,5 a 20); norapinefrina, 184,8 mug/24hs (VR= 15 a 80); dopamina, 513,5 mug/24hs (VR=65 a 400); metanefrina 0,08 mg/g de creatinina (VR<0,31); normetanefrina, 0,64 mg/g de creatinina (VR< 0,43); ácido vanilmandélico, 69,3 mumol/24 hs (VR= 10 a 35). A cintilografia com meta-iodobenzil-guanidina (MIBG) mostrou a presença de massa hiperfixante em regiao cervical direita, a qual foi confirmada pela ressonância magnética (RM), que mostrou também uma lesao contra-lateral, que entretanto, nao apresentou captaçao pelo MIBG. Foi realizada a exérese da lesao cervical direita, evoluindo com normalizaçao dos níveis da pressao arterial, catecolaminas e metabólitos urinários. A imuno-histoquímica identificou grânulos de secreçao para enolase neuroespecífica, neurofilamentos, cromogranina, somatostatina e serotonina, que confirmaram o diagnóstico de paraganglioma funcionante, e identificou a presença de anti-proteína S100, que é um preditor de bom prognóstico. O paciente será acompanhado com exames clínicos e laboratoriais periódicos, devido à lesao contra-lateral e para se detectar uma eventual recidiva do tumor à direita. Apesar da presença de fatores de bom prognóstico, estes tumores sao considerados potencialmente malignos.