Navegando por Palavras-chave "Deferoxamine"

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    Acesso aberto (Open Access)
    Baroreflex function in conscious rats submitted to iron overload
    (Associação Brasileira de Divulgação Científica, 2005-02-01) Cardoso, Leonardo Máximo; Pedrosa, Maria Lúcia Silva; Silva, Marcelo Eustáquio; Moraes, Márcio Flávio Dutra; Colombari, Eduardo [UNIFESP]; Chianca-Junior, Deoclécio Alves; Universidade Federal de Ouro Preto NUPEB Departamento de Ciências Biológicas; Universidade Federal de Ouro Preto Escola de Nutrição Departamento de Alimentos; Universidade Federal de Minas Gerais Instituto de Ciências Biológicas Departamento de Fisiologia e Biofísica; Universidade Federal de São Paulo (UNIFESP)
    Our hypothesis is that iron accumulated in tissue, rather than in serum, may compromise cardiovascular control. Male Fischer 344 rats weighing 180 to 220 g were divided into 2 groups. In the serum iron overload group (SIO, N = 12), 20 mg elemental iron was injected ip daily for 7 days. In the tissue iron overload group (TIO, N = 19), a smaller amount of elemental iron was injected (10 mg, daily) for 5 days followed by a resting period of 7 days. Reflex heart rate responses were elicited by iv injections of either phenylephrine (0.5 to 5.0 µg/kg) or sodium nitroprusside (1.0 to 10.0 µg/kg). Baroreflex curves were determined and fitted to sigmoidal equations and the baroreflex gain coefficient was evaluated. To evaluate the role of other than a direct effect of iron on tissue, acute treatment with the iron chelator deferoxamine (20 mg/kg, iv) was performed on the TIO group and the baroreflex was re-evaluated. At the end of the experiments, evaluation of iron levels in serum confirmed a pronounced overload for the SIO group (30-fold), in contrast to the TIO group (2-fold). Tissue levels of iron, however, were higher in the TIO group. The SIO protocol did not produce significant alterations in the baroreflex curve response, while the TIO protocol produced a nearly 2-fold increase in baroreflex gain (-4.34 ± 0.74 and -7.93 ± 1.08 bpm/mmHg, respectively). The TIO protocol animals treated with deferoxamine returned to sham levels of baroreflex gain (-3.7 ± 0.3 sham vs -3.6 ± 0.2 bpm/mmHg) 30 min after the injection. Our results indicate an effect of tissue iron overload on the enhancement of baroreflex sensitivity.
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    Efeito dos quelantes de ferro deferoxamina (DFO) e mimosina na função de neutrófilos humanos.
    (Universidade Federal de São Paulo, 2021-08-05) Santos, Nubia Gonçalves dos [UNIFESP]; Simon, Karin Argenti [UNIFESP]; Rettori, Daniel [UNIFESP]; http://lattes.cnpq.br/3940587107891484; http://lattes.cnpq.br/4340953066734170; http://lattes.cnpq.br/0950580797959768
    Os leucócitos polimorfonucleares possuem uma maquinaria complexa e diferenciada para lidar com infecções recorrentes em nosso corpo. A produção de espécies reativas de oxigênio (ERO) e nitrogênio (ERN) são fundamentais para o desempenho deste tipo celular, pois desencadeiam a formação de outros mecanismos efetores e são eficazes na degradação de microorganismos em fagolisossomas. O descontrole dessas funções pode acarretar, entre outros problemas, em estresse oxidativo, e consequentemente, trazer riscos à saúde humana. O estudo propôs testar e discutir possíveis moduladores da classe de quelantes em processos inflamatórios. Para isso, avaliou-se parâmetros de funcionalidade in vitro de leucócitos polimorfonucleares humanos, isolados de sangue periférico, na presença dos agentes quelantes de ferro deferoxamina (DFO) e do aminoácido não protéico mimosina. Com base nos conhecimentos sobre a produção intencional de ERO e de ERN, o “burst” oxidativo, aplicou-se o método de luminescência amplificada por luminol, estabelecendo um gradiente de concentração. O tratamento com os quelantes apontou uma diminuição significativa na produção de espécies reativas em células estimuladas com PMA e Zymosan. Os diferentes estímulos também influenciaram na intensidade com que essa diminuição ocorreu. Ainda não é possível descrever completamente o mecanismo chave por trás dessas reações, contudo os resultados obtidos corroboram a relevância do ferro na produção de ERO por neutrófilos estimulados e indicam um papel para o uso de quelantes na modulação da função oxidativa dessas células.
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    Urinary iron excretion induced by intravenous infusion of deferoxamine in ß-thalassemia homozygous patients
    (Associação Brasileira de Divulgação Científica, 2002-11-01) Boturão-Neto, Edmir [UNIFESP]; Marcopito, Luiz Francisco [UNIFESP]; Zago, M.a.; Universidade de São Paulo (USP); Universidade Federal de São Paulo (UNIFESP)
    The purpose of the present study was to identify noninvasive methods to evaluate the severity of iron overload in transfusion-dependent ß-thalassemia and the efficiency of intensive intravenous therapy as an additional tool for the treatment of iron-overloaded patients. Iron overload was evaluated for 26 ß-thalassemia homozygous patients, and 14 of them were submitted to intensive chelation therapy with high doses of intravenous deferoxamine (DF). Patients were classified into six groups of increasing clinical severity and were divided into compliant and non-compliant patients depending on their adherence to chronic chelation treatment. Several methods were used as indicators of iron overload. Total gain of transfusion iron, plasma ferritin, and urinary iron excretion in response to 20 to 60 mg/day subcutaneous DF for 8 to 12 h daily are useful to identify iron overload; however, urinary iron excretion in response to 9 g intravenous DF over 24 h and the increase of urinary iron excretion induced by high doses of the chelator are more reliable to identify different degrees of iron overload because of their correlation with the clinical grades of secondary hemochromatosis and the significant differences observed between the groups of compliant and non-compliant patients. Finally, the use of 3-9 g intravenous DF for 6-12 days led to a urinary iron excretion corresponding to 4.1 to 22.4% of the annual transfusion iron gain. Therefore, continuous intravenous DF at high doses may be an additional treatment for these patients, as a complement to the regular subcutaneous infusion at home, but requires individual planning and close monitoring of adverse reactions.