RESUMO
In order to identify and quantify free radicals in the tissues of patients with normal physiological and pathological states of births, we developed a method to evaluate the amount of free radicals in myometrium of subplacental area and from body of uterus, using electron spin resonance spectroscopy. Analysis of the concentration of free radicals in the myometrium in full-term pregnancy with normal labour and during uterine inertia was studied. The activities of Ca2+-ATPase, cytochrome c oxidase and succinate dehydrogenase in samples of these tissues were tested too. Low free radical concentrations in these tissues were associated with disturbances in contractile activity of myometrium along with reduction of Ca2+-ATPase, cytochrome c oxidase and succinate dehydrogenase activity. There proved to be an association between the level of free radicals in the tissues and alteration in the physiological processes.
Assuntos
Parto Obstétrico , Espectroscopia de Ressonância de Spin Eletrônica , Radicais Livres/análise , Miométrio/metabolismo , Inércia Uterina/metabolismo , ATPases Transportadoras de Cálcio/análise , ATPases Transportadoras de Cálcio/metabolismo , Complexo IV da Cadeia de Transporte de Elétrons/análise , Complexo IV da Cadeia de Transporte de Elétrons/metabolismo , Feminino , Humanos , Gravidez , Succinato Desidrogenase/análise , Succinato Desidrogenase/metabolismoRESUMO
The surface of liposomes and natural membranes has been studied by the method of "spin label--spin probe". Various nitroxyl radicals have been attached to membranes either dueto covalent binding with NH2-groups of phosphatidylethanolamine or due to hydrophobic interactions. Addition of paramagnetics of different charge signs (potassium ferricyanide and dibenzenechromium iodide) to spin labeled membranes results in a decrease of the EPR line intensity without marked broadening. Since the paramagnetic is attached to the membrane surface near the label it broadens the label's EPR spectrum so that it can not be observed. In this case one can observe only the spectrum of labels which have no paramagnetics in the vicinity, the nitroxyl part of radicals being inaccessible to direct paramagnetic impacts. The constants of binding of paramagnetics to the membrane surface have been determined from these experiments. All results (including the assymetry of label rotation) can be explained most simply by assuming that the polar lipid groups are oriented parallel to the membranes surface.