251 resultados para reactive oxygen metabolite


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Background: It is not well established whether the increased number of leukocytes in the seminal fluid impairs the outcomes of assisted reproductive technology (ART). This investigation analysed the outcomes of the intracytoplasmic sperm injection (ICSI) and intracytoplasmic morphologically selected sperm injection (IMSI) cycles in couples in which the male partner exhibited leukocytospermia.Methods: A total of 100 cycles in 100 couples were included in this study. For the ICSI or IMSI procedures, the patients were divided into two groups according to the presence or absence of leukocytospermia and then matched by (female) age:- ICSI: Group I (n = 25): Leukocytospermia - semen samples with a leukocyte count of greater than or equal to 1 x 10(6)/mL; and Group II (n = 25): Non-leukocytospermia - semen samples with a leukocyte count < 1 x 10(6)/mL.- IMSI: Group I (n = 25): Leukocytospermia; and Group II (n = 25): Non-leukocytospermia.The endpoints included the rates of fertilisation, implantation, clinical pregnancy, miscarriage, ongoing pregnancy and live birth. Student's t-tests, Mann-Whitney tests and Chi-square tests were performed, and P < 0.05 was considered significant.Results: The data from the ICSI groups showed that leukocytospermia did not have a negative influence on the rates of fertilisation (Group I: 57.9+/-30.2%, Group II: 61.9+/-27.7%; P = 0.74), implantation (Group I: 12.3%; Group II: 13.5%; P = 0.93), clinical pregnancy (Group I: 24%; Group II: 24%; P = 1.0), miscarriage ( Group I: 0, Group II: 0), ongoing pregnancy (Group I: 24%; Group II: 24%; P = 1.0), or live births (Group I: 24%; Group II: 24%; P = 1.0). Similarly, the data from the IMSI groups also showed that the leukocytospermia did not have a negative influence on the rates of fertilisation (Group I: 67.6+/-24.6%, Group II: 59.5+/-28.1%; P = 0.36), implantation (Group I: 17.5%; Group II: 16.7%; P = 0.90), clinical pregnancy (Group I: 28%; Group II: 24%; P = 1.0), miscarriage (Group I: 14.3%; Group II: 0; P = 0.33), ongoing pregnancy (Group I: 24%; Group II: 24%; P = 1.0), or live births (Group I: 24%, 6/25; Group II: 24%, 6/25; P = 1.0).Conclusions: The results indicate that the leukocytospermia may not have a negative effect on the outcomes of ICSI or IMSI cycles. Nevertheless, it seems that it is necessary to more precisely determine the effects, if any, of seminal leukocytes on fertilisation and implantation processes. Such efforts will help to establish a more reliable leukocyte threshold, which could eventually demonstrate whether there is a negative influence on the ART procedures.

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Diabetes mellitus (DM) é uma síndrome de etiologia múltipla caracterizada por hiperglicemia crônica. Esta hiperglicemia induz o aumento na produção de espécies reativas de oxigênio (ERO) e diminuição das defesas antioxidantes. Devido às complicações causadas pelo diabete, muitos indivíduos optam por terapias alternativas à base de plantas medicinais para amenizar seus efeitos. Sendo assim, nesta revisão de literatura, foram analisados e descritos diversos trabalhos experimentais com a utilização de animais diabéticos para comprovar os efeitos antioxidantes de algumas dessas plantas e verificar se os títulos e resumos disponibilizados nos artigos são compatíveis aos objetivos de nossa busca.

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Doxorubicin (DOX) is an efficient chemotherapeutic agent used against several types of tumors; however, its use is limited due to severe cardiotoxicity. Since it is accepted that reactive oxygen species are involved in DOX-induced cardiotoxicity, antioxidant agents have been used to attenuate its side effects. To determine tomato-oleoresin protection against cardiac oxidative DNA damage induced by DOX, we distributed Wistar male rats in control (C), lycopene (L), DOX (D) and DOX+lycopene (DL) groups. They received corn oil (C, D) or tomato-oleoresin (5 mg/kg body wt. day) (L, DL) by gavage for a 7-week period. They also received saline (C, L) or DOX (4 ma/kg body wt.) (D, DL) intraperitoneally at the 3rd, 4th, 5th, and at 6th week. Lycopene absorption was checked by HPLC. Cardiac oxidative DNA damage was evaluated by the alkaline Comet assay using formamidopyrimidine-DNA glycosylase (FPG) and endonuclease III (endo 111). Cardiomyocyte levels of SBs, SBs FPG and SBs Endo III were higher in rats from D when compared to other groups. DNA damage levels in cardiomyocytes from DL were not different when compared to C and L groups. The viability of cardiomyocytes from D or DL was lower than C or L groups (p < 0.01). Lycopene levels (mean +/- S.D. nmol/kg) in saponified hearts were similar between L (47.43 +/- 11.78) and DL (49.85 +/- 16.24) groups. Our results showed: (1) lycopene absorption was confirmed by its cardiac levels; (2) DOX-induced oxidative DNA damage in cardiomyocyte; (3) tomato-oleoresin supplementation protected against cardiomyocyte oxidative DNA damage. (c) 2007 Elsevier B.V. All rights reserved.

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A infecção pelo Helicobacter pylori (H. pylori) induz inflamação persistente na mucosa gástrica com diferentes lesões orgânicas em humanos, tais como gastrite crônica, úlcera péptica e câncer gástrico. Os fatores determinantes desses diferentes resultados incluem a intensidade e a distribuição da inflamação induzida pelo H. pylori na mucosa gástrica. Evidências recentes demonstram que cepas do H. pylori apresentam diversidade genotípica, cujos produtos acionam o processo inflamatório por meio de mediadores e citocinas, que podem levar a diferentes graus de resposta inflamatória do hospedeiro, resultando em diferentes destinos patológicos. Cepas H. pylori com a ilha de patogenicidade cag induzem resposta inflamatória mais grave, através da ativação da transcrição de genes, aumentando o risco para desenvolvimento de úlcera péptica e câncer gástrico. O estresse oxidativo e nitrosativo induzido pela inflamação desempenha importante papel na carcinogênese gástrica como mediador da formação ou ativação de cancerígenos, danos no DNA, bem como de alterações da proliferação celular e da apoptose.

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As espécies reativas do oxigênio (ERO) são moléculas instáveis e extremamente reativas capazes de transformar outras moléculas com as quais colidem. As ERO são geradas em grande quantidade durante o estresse oxidativo, condição em que são afetadas moléculas como proteínas, carboidratos, lipídeos e ácido nucleicos. Neste trabalho, são discutidos os principais conceitos sobre os radicais livres e as ERO: principais tipos, sua formação e a forma como atuam sobre as estruturas celulares, provocando lesão tecidual significativa. Os principais sistemas de defesa antioxidantes e a influência do aumento na produção dessas ERO no trato respiratório de grandes animais também são discutidos, dando ênfase ao envolvimento das ERO em doenças como a pneumonia em ruminantes e na obstrução recorrente das vias aéreas e a hemorragia pulmonar induzida por exercício em equinos.

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Semen manipulation and cryopreservation-thaw procedures may accelerate the generation of reactive oxygen species (ROS). Sperm exposure to large amounts of ROS has been shown to cause membrane lipid peroxidation and cellular injury to the sperm. The objective of this study was to overcome the ROS production in frozen-thawed ram semen by the addition of the antioxidants catalase or Trolox to semen following thawing. Frozen-thawed ram semen (100 x 10(6) sperm/straw) was supplemented with PBS (control group), 100 mu g/ml catalase, or 100 mu M Trolox/10(8) sperm (catalase and Trolox being dissolved in PBS) and incubated (37 degrees C) for 5 min. Under the experimental conditions used in this study, the catalase and Trolox antioxidants failed to protect the sperm from the spontaneous production of ROS. However, when lipid peroxidation was induced by iron (FeSO(4)), the addition of Trolox promoted a reduction (P < 0.05) in the formation of TBARS in the semen, compared to the control and catalase semen samples. The generation of TBARS and H(2)O(2) occurred in the extender alone, without the presence of sperm cells. In conclusion, the addition of Trolox to frozen-thawed ram semen could be beneficial as it decreases the production of TBARS when oxidative stress is induced. It is possible that a longer incubation period could lead to different results. The concentration of catalase also needs to be further evaluated. The extender could contribute to the oxidative stress of sperm, as it is a source of ROS during the cryopreservation of semen. (C) 2010 Elsevier B.V. All rights reserved.

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