Effect of pasteurization on the antioxidant and oxidant properties of human milk / Efeito da pasteurização nas propriedades antioxidantes e oxidantes do leite humano

ABSTRACT Objective: To evaluate the effect of pasteurization on antioxidant and oxidant properties of human milk. Methods: 42 samples of milk before and after pasteurisation were used to evaluate the antioxidant activity by the ferric reducing capacity and by scavenging the 2,2'-azino-bis 3-ethylbenzthiazoline-6-sulfonic acid radical. Lipid peroxidation was estimated by the concentration of malondialdehyde product using the thiobarbituric acid reactive substances assay and by the evaluation of advanced oxidation protein products. Results: No significant difference was observed in fresh human milk and after pasteurization in relation to antioxidant properties determined by the ferric reducing capacity (50.0±3.4% and 48.8±3.0%, respectively) and by scavenging the 2,2'-azino-bis 3-ethylbenzthiazoline-6-sulfonic acid radical (28.9±1.5% and 31.2±1.3%, respectively). The results of malondialdehyde (62.6±4.1 and 64.3±3.6 µM/mg) and protein oxidation products (59.4±3.4 and 54.2±3.8 µM/L) of fresh and pasteurized milk, respectively, did not exhibited any significant difference. Conclusions: This data showed that human milk has an important antioxidant activity and that the pasteurizing process does not influence the antioxidant capacity, avoiding the peroxidation of breast milk lipids and the formation of advanced protein oxidation products.

RESUMO Objetivo: Avaliar o efeito da pasteurização nas propriedades antioxidantes e oxidantes do leite humano. Métodos: Foram utilizadas 42 amostras de leite cru e após a pasteurização, para avaliação da atividade antioxidante pelos métodos da capacidade redutora do ferro e sequestro dos radicais derivados do ácido 2,2'-azino-bis (3-etilbenzotiazolina-6-sulfônico). A peroxidação lipídica (PL) foi estimada pela determinação das substâncias reativas ao ácido tiobarbitúrico e pela avaliação dos produtos proteicos de oxidação avançada. Resultados: Não se observou diferença significante no leite humano cru nem após a pasteurização em relação às propriedades antioxidantes determinadas pelo método da redução do ferro (50,0±3,4% e 48,8±3,0%, respectivamente) e pelo sequestro dos radicais derivados do ácido 2,2'-azino-bis (3-etilbenzotiazolina-6-sulfônico) (28,9±1,5% e 31,2±1,3%, respectivamente). Os resultados médios de malondialdeído [MDA] (62,6±4,1 e 64,3±3,6 µM/mg) e produtos de oxidação proteica (59,4±3,4 e 54,2±3,8 µM/L) entre os grupos leite fresco e leite pasteurizado, respectivamente, não evidenciaram diferença significante. Conclusões: Os dados demonstraram que o leite humano possui importante atividade antioxidante e que o processo de pasteurização não interfere nessa propriedade, evitando assim a peroxidação dos lipídios e a formação de produtos avançados de oxidação proteica.

Oxidative stress of crystalline lens in rat menopausal model / O estresse oxidativo do cristalino em modelo de rata na menopausa

ABSTRACT Purpose: To evaluate lenticular oxidative stress in rat menopausal models. Methods: Forty Wistar female albino rats were included in this study. A total of thirty rats underwent oophorectomy to generate a menopausal model. Ten rats that did not undergo oophorectomy formed the control group (Group 1). From the rats that underwent oophorectomy, 10 formed the menopause control group (Group 2), 10 were administered a daily injection of methylprednisolone until the end of the study (Group 3), and the remaining 10 rats were administered intraperitoneal streptozocin to induce diabetes mellitus (Group 4). Total oxidant status (TOS), total antioxidant capacity (TAC), and oxidative stress index (OSI) measurements of the crystalline lenses were analyzed. Results: The mean OSI was the lowest in group 1 and highest in group 4. Nevertheless, the difference between the groups was not statistically significant in terms of OSI (p >0.05). The mean TOS values were similar between the groups (p >0.05), whereas the mean TAC of group 1 was significantly higher than that of the other groups (p <0.001). Conclusions: Our results indicate that menopause may not promote cataract formation.

RESUMO Objetivo: Avaliar o estresse oxidativo lenticular em modelos de ratas na menopausa. Métodos: Quarenta ratos albinos femininos tipo Wistar foram incluídos neste estudo. Trinta ratas foram submetidas à ooforectomia para gerar o modelo de menopausa e 10 ratas formaram o grupo controle (Grupo 1). Dentre as ratas ooforectomizadas, 10 formaram o grupo controle menopausa (Grupo 2), 10 ratas receberam injeção diária de metilprednisolona até ao final do estudo (Grupo 3) e 10 ratas receberam estreptozotocina por via intraperitoneal para induzir diabetes mellitus (Grupo 4). O estado oxidante total (TOS), a capacidade total antioxidante (TAC) e as medições do índice de estresse oxidativo (OSI) dos cristalinos foram analisados. Resultados: A média de OSI foi menor no grupo 1 e maior no grupo 4. Todavia, a diferença entre os grupos não foi estatisticamente significativa (p>0,05). Os valores médios TOS foram semelhantes entre os grupos (p>0,05), enquanto a média de TAC grupo 1 foi mais elevada do que nos outros grupos ( p<0,001). Conclusões: Nossos resultados indicam que a menopausa podem não promover a formação de catarata.

Fenthion, an organophosphorus pesticide, induces alterations in oxidant/antioxidant status and histopathological disorders in cerebrum and cerebellum of suckling rats.

Fenthion (FEN) is an organophosphorus pesticide known for its wide toxic manifestations. In this study, the effects of FEN were evaluated on the cerebrum and cerebellum oxidant/antioxidant status and histopathological disorders in the suckling rats. Pregnant rats were divided into two groups: control group received pure water, while FEN group received daily by their drinking water 551 ppm of FEN from the 14th day of pregnancy until day 14 after delivery. Acetylcholine esterase (AChE) activity was inhibited in both the cerebrum and cerebellum of suckling rats whose mothers were treated with FEN. The cerebrum and cerebellum oxidative damage was demonstrated by a significant increase of malondialdehyde (MDA), advanced oxidation protein product and glutathione (GSH) levels and disturbance in the antioxidant enzyme activities. A significant decline of non-protein thiol and vitamin C levels was also observed. These changes were confirmed by histopathological observations which were marked by pyknotic neurons in the cerebrum and apoptotic cells in the cerebellum of FEN-treated rats. In the cerebellum of FEN-treated rats, the most conspicuous damage was the absence of external granular layer, indicating growth retardation. These data suggested that exposure of pregnant and lactating rats to FEN induced oxidative stress and histopathological disorders in the cerebrum and cerebellum of their pups. Thus, the use of FEN must be under strict control, especially for pregnant and lactating mothers.

Oxidant and Antioxidant Status in Parkinson’s Disease.

Parkinson’s disease (PD) is a progressive, neurological disease that mainly affects movements and occurs at older ages and is clinically characterized by resting tremor, rigidity, bradykinesia and postural imbalance. These clinical manifestations of PD are caused by a selective degeneration of dopamine-producing neurons in substantia nigra in the brain stem and the consequent dopamine shortage in the striatum. Oxidants and antioxidants related substances may contribute to the pathogenesis and the progression of Parkinson’s disease. Research can make great progress in understanding and further treating the PD. This study demonstrates significant variation of oxidants-antioxidants status in Parkinson’s disease. Oxidative stress plays a crucial role in progression of PD; however, oxidative stress is a cause or the consequence of PD is debatable. In our study we observed there is significant increase in the levels of serum Malondialdehyde (p< 0.001), Nitric oxide end products (p< 0.001), and significant decrease in the activity of Glutathione peroxidase (p< 0.001), Superoxide dismutase (p< 0.001), and Catalase (p< 0.001) in PD patients as compared with controls. Further Vitamin C (p< 0.05), Vitamin E (p< 0.05) significantly decreased, but Uric acid levels (p> 0.05) remain unchanged and this may be due to compensatory mechanism of body against oxidative stress, which not allowed much alteration in other parameter in the PD patients as compared with controls.

Testes fitoquímicos em extratos foliares de Oeceoclades maculata Lindl. (Orchidaceae) / Phytochemical tests in Oeceoclades maculata Lindl. (Orchidaceae) leaf extracts

O presente trabalho teve por objetivo determinar a capacidade antioxidante de Oeceoclades maculata. A atividade foi determinada de acordo com a capacidade do extrato hidroalcoólico das folhas reduzir o radical DPPH. Os resultados obtidos permitem concluir que os conteúdos de polifenóis e flavonas/flavonóis são maiores no extrato preparado a frio (EBHF) do que no extrato preparado a quente (EBHQ), sugerindo que o aquecimento usado na preparação do extrato altera esses componentes ativos. Portanto, para esta espécie deve ser realizado o método de extração a frio para conservar as substâncias que possuem atividade antioxidante.

This work aimed to determine the antioxidant capacity of Oeceoclades maculata. The antioxidant activity was determined in accordance with the ability of the hydroalcoholic extract of the leaves to reduce the DPPH radical. The results showed that the polyphenol and flavonoid contents are greater in the cold extract (EBHF) than in the hot extract (EBHQ), which suggests that the heating effect in the preparation of the extract modifies these active compounds. Therefore, for this species, the cold extraction method must be carried in order to conserve the substances with antioxidant activity.

An oxidant and organic solvent tolerant alkaline lipase by P. aeruginosa mutant: downstream processing and biochemical characterization

An extracellular alkaline lipase from Pseudomonas aeruginosa mutant has been purified to homogeneity using acetone precipitation followed by anion exchange and gel filtration chromatography and resulted in 27-fold purification with 19.6% final recovery. SDS-PAGE study suggested that the purified lipase has an apparent molecular mass of 67 kDa. The optimum temperature and pH for the purified lipase were 45°C and 8.0, respectively. The enzyme showed considerable stability in pH range of 7.0-11.0 and temperature range 35-55 °C. The metal ions Ca2+, Mg2+ and Na+ tend to increase the enzyme activity, whereas, Fe2+ and Mn2+ ions resulted in discreet decrease in the activity. Divalent cations Ca+2 and Mg+2 seemed to protect the enzyme against thermal denaturation at high temperatures and in presence of Ca+2 (5 mM) the optimum temperature shifted from 45°C to 55°C. The purified lipase displayed significant stability in the presence of several hydrophilic and hydrophobic organic solvents (25%, v/v) up to 168 h. The pure enzyme preparation exhibited significant stability and compatibility with oxidizing agents and commercial detergents as it retained 40-70% of its original activities. The values of Km and Vmax for p-nitrophenyl palmitate (p-NPP) under optimal conditions were determined to be 2.0 mg.mL-1 and 5000 μg.mL-1.min-1, respectively.

Emergence of oxyl radicals as selective oxidants.

Hydroxyl radicals (HO·) are derived in Fenton reaction with ferrous salt and H2O2 in acid medium, and at neutral pH, metal-oxyl radicals (M-O·) predominate. Evidence is accumulating that M-O· radicals are also active in oxidation reactions, in addition to metal-oxo (M=O) now shown in many publications. Reactivity of these radicals gives selective oxidized products useful in cellular activities, in contrast to purported indiscriminate cell damage by hydroxyl radicals. Reactions with vanadium compounds, such as diperoxovanadate, peroxo-bridged mixed valency divanadate, vanadium-oxyl radical, tetravalent vanadyl and decavanadate illustrates selective gain in oxidative capacity of oxo- and oxyl- species. Occurrence of ESR signals typical of hydroxyl radicals is demonstrated in cell homogenates and tissue perfusates treated with spin trap agents. It is known for a long time lipid peroxides are formed in tissue microsomal systems exclusively in presence of salts of iron, among many metals tested. Oxygen and a reducing agent, ascorbate (non-enzymic) or NADPH (enzymic) are required to produce 'ferryl', the chelated Fe=O active form (possibly Fe-O· and Fe-O-O-Fe ?) for the crucial step of H-atom abstraction. Yet literature is replete with unsupported affirmations that hydroxyl radicals initiate lipid peroxidation, an unexplained fixation of mindset. The best-known ·OH generator, a mixture of ferrous salt and H2O2, does not promote lipid peroxidation, nor do the many hydroxyl radical quenching agents stop it. The availability of oxo and oxyl-radical forms with transition metals, and also with non metals, P, S, N and V, calls for expansion of vision beyond superoxide and hydroxyl radicals and explore functions of multiple oxygen radicals for their biological relevance.

Efeito da ingestão crônica do fluoreto sobre o sistema oxidante/antioxidante de ratos / Effect of chronic fluoride intake in the oxidant/antioxidant system of rats

A ingestão excessiva de fluoreto por um longo período de tempo pode resultar em fluorose, que pode causar manifestações dentárias e esqueléticas. Danos metabólicos, funcionais e estruturais causados pela fluorose crônica tem sido relatados em vários tecidos. O objetivo deste estudo foi avaliar os efeitos do fluoreto administrado na água de beber, da administração de fluoreto na água de beber na defesa antioxidante de ratos. Quatro grupos de ratos wistar foram usados (n=10/grupo). Os animais receberam água de beber contendo 0 (controle), 5, 15 ou 50 ppm de fluoreto durante 60 dias. Eles foram eutanasiados e os tecidos (fígado, rins e coração) e plasma foram coletados e homogenizados. Superóxido dismutase (SOD), catalase (CAT), glutationa peroxidase (GPx), glutationa reduzida (GSH), substâncias antioxidantes totais (SAT), substâncias reativas ao ácido tiobarbitúrico (TBARS), hidroperóxido de lipídios (HL) e fluoreto foram análisadas. Dados foram analisados por ANOVA e teste de Tukey ou Kruskal-Wallis e teste de Dunn (p<0,05). Nos rins, SOD, GPx, GSH e SAT diminuiram e fluoreto e HL aumentaram significantivamente. No fígado, CAT e TBARS diminuiram, SOD, HL e SAT aumentaram significativamente. No coração, GPx aumentou significativamente. No plasma, SOD e HL diminuiram significativamente. Em resumo, esses resultados mostram que a administração crônica de fluoreto altera o sistema antioxidante de ratos. Nosso dados sugerem que a exposição em níveis elevados de fluoreto, a conversão do ânion superóxido em água nos rins parecem ocorrer principalmente através da SOD e CAT, com baixa participação do sistema glutationa, diferindo do que parece ocorrer no fígado.

Excessive fluoride intake over a long period of time could result in fluorosis, which can lead to dental and skeletal manifestations. Metabolic, functional and structural damages caused by chronic fluorosis have been reported in many tissues. The aim of this study was to evaluate the effect of fluoride, administered in drinking water, in the antioxidant defense of rats. Four groups of Wistar rats were included (n=10/group). The animals received drinking water containing 0 (control), 5, 15 or 50 ppm of fluoride during 60 days. They were euthanized and the tissues (liver, kidney and heart) and plasma were collected and homogenized. Superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), reduced glutathione (GSH), antioxidants, thiobarbituric acid reactive substances (TBARS), lipid hydroperoxide (LH), and fluoride were analyzed. Data were analyzed by ANOVA and Tukeys test or Kruskal-Wallis and Dunns tests (p<0.05). In the kidney SOD, GPx, GSH and SAT decreased and fluoride and LH increased significantly. In the liver, CAT and TBARS decreased and fluoride, SOD, LH and SAT increased significantly. In the heart, GPx increased significantly. In the plasma, SOD and LH decreased significantly. In summary, these results show that chronic fluoride administration alters the antioxidant system of the rats. Our data suggest that upon exposure to high levels of fluoride, the conversion of the superoxide anion to water in the kidney seems to occur mainly through the SOD and CAT, with a low participation of the glutathione system, differing from what seems to occur in the liver.

Efeito da ingestão crônica do fluoreto sobre o sistema oxidante/antioxidante de ratos / Effect of chronic fluoride intake in the oxidant/antioxidant system of rats

A ingestão excessiva de fluoreto por um longo período de tempo pode resultar em fluorose, que pode causar manifestações dentárias e esqueléticas. Danos metabólicos, funcionais e estruturais causados pela fluorose crônica tem sido relatados em vários tecidos. O objetivo deste estudo foi avaliar os efeitos do fluoreto administrado na água de beber, da administração de fluoreto na água de beber na defesa antioxidante de ratos. Quatro grupos de ratos wistar foram usados (n=10/grupo). Os animais receberam água de beber contendo 0 (controle), 5, 15 ou 50 ppm de fluoreto durante 60 dias. Eles foram eutanasiados e os tecidos (fígado, rins e coração) e plasma foram coletados e homogenizados. Superóxido dismutase (SOD), catalase (CAT), glutationa peroxidase (GPx), glutationa reduzida (GSH), substâncias antioxidantes totais (SAT), substâncias reativas ao ácido tiobarbitúrico (TBARS), hidroperóxido de lipídios (HL) e fluoreto foram análisadas. Dados foram analisados por ANOVA e teste de Tukey ou Kruskal-Wallis e teste de Dunn (p<0,05). Nos rins, SOD, GPx, GSH e SAT diminuiram e fluoreto e HL aumentaram significantivamente. No fígado, CAT e TBARS diminuiram, SOD, HL e SAT aumentaram significativamente. No coração, GPx aumentou significativamente. No plasma, SOD e HL diminuiram significativamente. Em resumo, esses resultados mostram que a administração crônica de fluoreto altera o sistema antioxidante de ratos. Nosso dados sugerem que a exposição em níveis elevados de fluoreto, a conversão do ânion superóxido em água nos rins parecem ocorrer principalmente através da SOD e CAT, com baixa participação do sistema glutationa, diferindo do que parece ocorrer no fígado.

Excessive fluoride intake over a long period of time could result in fluorosis, which can lead to dental and skeletal manifestations. Metabolic, functional and structural damages caused by chronic fluorosis have been reported in many tissues. The aim of this study was to evaluate the effect of fluoride, administered in drinking water, in the antioxidant defense of rats. Four groups of Wistar rats were included (n=10/group). The animals received drinking water containing 0 (control), 5, 15 or 50 ppm of fluoride during 60 days. They were euthanized and the tissues (liver, kidney and heart) and plasma were collected and homogenized. Superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), reduced glutathione (GSH), antioxidants, thiobarbituric acid reactive substances (TBARS), lipid hydroperoxide (LH), and fluoride were analyzed. Data were analyzed by ANOVA and Tukeys test or Kruskal-Wallis and Dunns tests (p<0.05). In the kidney SOD, GPx, GSH and SAT decreased and fluoride and LH increased significantly. In the liver, CAT and TBARS decreased and fluoride, SOD, LH and SAT increased significantly. In the heart, GPx increased significantly. In the plasma, SOD and LH decreased significantly. In summary, these results show that chronic fluoride administration alters the antioxidant system of the rats. Our data suggest that upon exposure to high levels of fluoride, the conversion of the superoxide anion to water in the kidney seems to occur mainly through the SOD and CAT, with a low participation of the glutathione system, differing from what seems to occur in the liver.

Therapeutic role of L-arginine on free radical scavenging system in ischemic heart diseases.

Increased production of free radicals under oxidative stress conditions plays a vital role in the impairment of endothelial function and also in the pathogenesis of ischemic heart diseases. Ischemia, followed by reperfusion, leads to the exacerbated formation of oxy- free radicals. These reactive oxygen species through a chain of reactions damage the cardiomyocytes and cause more injury to the myocardium. L-Arginine is reported to act as free radical scavenger, inhibits the activity of pro-oxidant enzymes and thus acts as an antioxidant and these roles of L-arginine are mediated by nitric oxide (NO). In the present study, the effect of oral administration of L-arginine (3 g/day for 7 days) on some antioxidant enzymes, total thiols, lipid peroxidation measured as malondialdehyde (MDA), and plasma ascorbate levels in myocardial ischemic patients was investigated. We observed an increase in the activity of superoxide dismutase (SOD), total thiols (T-SH) and plasma ascorbate levels and a decrease in the activity of xanthine oxidase (XO), MDA levels, carbonyl content and serum cholesterol in the patients on oral administration of L-arginine. The present study demonstrates that L-arginine administration may be beneficial to patients with myocardial ischemic disorders, such as acute myocardial infarction and acute angina.

Oxidant stress due to non ionic low osmolar contrast medium in rat kidney.

Background & objectives: Contrast media may cause contrast-induced nephropathy (CIN) in risk group. This study was taken up to establish possible effects of non ionic low osmolar contrast medium administration on oxidant/antioxidant status and nitric oxide (NO) levels in rat kidney tissues. Methods: Fourteen female, 14 wk old Wistar-albino rats were divided into 2 groups of 7 rats each (control and contrast groups). Non ionic low osmolar contrast medium was administered iv to the animals in the contrast group. The day after, animals were sacrificed and malondialdehyde (MDA) and NO levels and activities of antioxidant [superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and catalase (CAT)] and oxidant [xanthine oxidase (XO)] enzymes were measured in kidney tissues. Serum creatinine levels were measured to evaluate kidney functions. Results: Contrast medium administration caused an increase in MDA levels and a decrease in NO levels in kidney tissues. Interpretation & conclusions: The results suggest that non ionic low osmolar contrast medium administration leads to accelerated oxidant reactions and decreased NO level in rat kidney tissues. Further studies need to be done to assess the role of these changes in CIN.

Evolução de biomarcadores de estresse oxidativo e relação com a performance competitiva em dois momentos da temporada de treinamento de natação / Evolution of oxidative stress biomarkers and correlation with competitive performance in two moments of the swimming training season

Introdução: Estudos têm demonstrado aumento na formação de espécies reativas de oxigênio após o esforço físico intenso. Esses eventos podem aumentar a suscetibilidade das células musculares a danos oxidativos como a peroxidação lipídica. Assim, variações na intensidade e no volume de treinamento durante a temporada podem modular o metabolismo oxidativo e influenciar a performance dos atletas. OBJETIVO: Estudar a evolução de biomarcadores de peroxidação lipídica em dois momentos de um ciclo periodizado de treinamento e relacionar com a performance competitiva de natação. MÉTODOS: Participaram do presente estudo 16 nadadores (nove do gênero masculino e sete do feminino). Amostras de sangue foram coletadas em dois períodos do ciclo de treinamento: período preparatório específico e período de polimento. Espécies reativas ao ácido tiobarbitúrico (TBARS) e peróxidos totais foram determinados como biomarcadores de peroxidação lípidica. Creatina quinase foi determinada como parâmetro de dano celular muscular. O índice técnico alcançado no estilo de especialidade de cada atleta foi utilizado como parâmetro de performance competitiva. O índice técnico foi determinado na competição preparatória Troféu Electro Bonini realizada no período preparatório específico, e no Campeonato Paulista realizado no final do período de polimento. RESULTADOS: Foi encontrado aumento significativo (p < 0,05) no índice técnico no Campeonato Paulista (769,6 ± 51,1 pontos) em relação ao Troféu Electro Bonini (751,1 ± 55,7 pontos). Significativas reduções na concentração de TBARS (5,7 ± 2,9 vs 3,3 ± 2,2µmol/L) e peróxidos totais (45,1 ± 20,6 vs 29,6 ± 13,0, µmol H2O2/L) foram encontrados no período de polimento com relação ao período preparatório específico. O mesmo não foi encontrado para creatina quinase (123,6 ± 60,1 vs 137,4 ± 74,9U/L). CONCLUSÃO: A significativa diminuição nos biomarcadores de peroxidação lipídica decorrente do decréscimo no volume e intensidade do treinamento ...

Introduction: Studies have shown increase in the formation of oxygen reactive species after intense physical exertion. These events may increase the susceptibility of muscular cells to oxidative damage such as lipid per-oxidation. Thus, variations in training intensity as well as volume during the season may modulate the oxidative stress and influence in performance of athletes. AIM: To study the evolution of lipid peroxidation biomarkers in two moments of a periodized cycle of training and correlate it with swimming competitive performance. METHODS: 16 swimmers participated in this study (9 males and 7 females). Blood samples were collected in two periods of the training cycle: specific preparation training and tapering period. Species reactive to thiobarbituric acid (TBARS) and total peroxides were determined as lipid peroxidation biomarkers. Creatine kinase was determined as a parameter of muscular cell damage. The technical index reached in the style of specialization of each athlete was used as a competitive performance parameter. The technical index was determined in the preparatory competition Trophy Electro Bonini carried out in the specific preparatory period and in the Championship of São Paulo State carried out in the end of the tapering period (769.6 ± 51.1 points) in comparison with the Trophy Electro Bonini (751.1 ± 55.7 points). Significant reductions In the TBARS concentration ((5.7 ± 2.9 vs 3.3 ± 2.2µmol/L) and total peroxides (45.1±20.6 vs 29.6±13.0 µmol H2O2/L) were found In the tapering period concerning the specific preparatory period. The same situation was not found for creatine kinase ((123.6 ± 60.1 vs 137.4 ± 74.9U/L). CONCLUSION: The significant decrease in the biomarkers of lipid peroxidation derived from the decrease in the volume and intensity of training after the tapering training demonstrates the influence of the training variations on the oxidative stress and its possible relation with performance.

Oxidant/antioxidant balance in patients with thyroid cancer

PURPOSE: To compare the antioxidant enzyme activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and the levels of lipid peroxidation product malondialdehyde (MDA) in blood samples of thyroid cancer patients compared to healthy controls. METHODS: 43 control subjects (mean age 44±13 years) and 43 patients (43±13 years) presented with multinodular goiter whose fine needle aspiration revealed malignant cytology were included into this study. The SOD, MDA and GSH-Px activities were measured in control subjects, and before/20 days after thyroidectomy in thyroid cancer patients. RESULTS: SOD activities of pre-thyroidectomy, post-thyroidectomy and control groups were not different (p>0.05). Before thyroidectomy GSH-Px activities were lower (p<0.05) and MDA levels were higher (p<0.05) than the control group. In post- thyroidectomy, GSH-Px activity (p<0.05) increased, and MDA levels (p<0.05) decreased compared to prethyroidectomy levels. After thyroidectomy GSH-Px activity was significantly higher than the control group (p<0.05). Although post-thyroidectomy MDA levels significantly decreased, they were still higher than the control group (p<0.05). CONCLUSION: The superoxide dismutase does not seem to change with thyroid cancer and thyroidectomy but both antioxidant glutathione peroxidase and lipid peroxidation product malondialdehyde do. These preliminary findings may point out oxidant/antioxidant imbalance associated with thyroid cancer.

Evidencias de la participación del peroxinitrito en diversas enfermedades / Role of peroxynitrite anion in different diseases

Peroxynitrite (ONOO-) is a reactive nitrogen specie produced by the reaction between nitric oxide (NO• ) and super-oxide anion (O2.-). NO• is produced by nitric oxide synthase (NOS) and O2.- is formed by the addition of an electron to O2 in enzymatic as well as nonenzymatic way. NADPH oxidase and xanthine oxidase are some of the enzymes involved in O2.-formation. ONOO- is an oxidant specie which is able to modify a great number of biomolecules such as aminoacids, proteins, enzymes and cofactors. ONOO - is able to induce nitration leading to the formation of 3-nytrotyrosine. This change has been widely studied, and although it is not only produced by ONOO-, but also by other reactive nitrogen species, it has been accepted like footprint of ONOO-. The excessive production of reactive nitrogen species is known as nitrosative stress that is able to induce structural damage leading to the loss of cell function. Furthermore, synthetic metalloporphyrins that metabolize ONOO- in a specific way are being used to determine if ONOO- is involved in different diseases, such as Alzheimer, Huntington, diabetes, hypertension, arthritis, colitis, cardiac and renal complications. Finally, these metalloporphyrins may be of potential therapeutic value in diseases related to ONOO- production.

El peroxinitrito (ONOO-) es una especie reactiva de nitrógeno formada por la reacción entre el óxido nítrico (NO•) y el anión superóxido (O2.- ). El NO' es sintetizado por la sintasa de óxido nítrico (NOS) y el O2•- se puede sintetizar de forma no enzimática, por la adición de un electrón al O2 o por medio de diversas enzimas como la NADPH oxidasa y la xantina oxidasa. El ONOO-es una especie oxidante capaz de modificar un gran número de biomoléculas entre las que se encuentran aminoácidos, proteínas, enzimas y cofactores de enzimas. El ONOO- puede inducir nitración de residuos de tirosina promoviendo la formación de 3-nitrotirosina (3-NT). Esta modificación ha sido muy estudiada y aunque no es producida exclusivamente por ONOO- sino también por otras especies reactivas de nitrógeno, se acepta actualmente como una evidencia de la formación de ONOO-. El aumento excesivo de este último, así como de otras especies reactivas de nitrógeno se conoce como estrés nitrosativo y puede causar daño estructural alterando la funcionalidad de las células. Por otra parte, se han desarrollado una serie de metaloporfirinas que descomponen específicamente al ONOO- y éstas han ayudado a determinar que el ONOO - es una especie implicada en enfermedades como Alzheimer, Huntington, diabetes, hipertensión, artritis, colitis y diversas complicaciones cardiacas y renales. Además, estas metaloporfirinas pueden ser de utilidad terapéutica en aquellas enfermedades asociadas a la producción de ONOO-.

Prevention of chromate induced oxidative stress by alpha-lipoic acid.

The parenteral administration of alpha-lipoic acid (LA) protected against chromate induced oxidative stress in mouse liver. A shift in Cr induced pro-oxidant state to antioxidant-state by LA was noteworthy. The degree of protection was significant and similar in different LA administration regimens (prior-, co- and post- parenteral Cr exposure) explored. An improved status of the tissue antioxidants by LA appeared to be the mechanism of mitigation. The results are of chemopreventive value and suggest a possible alternative to ascorbic acid for abrogation of Cr toxicity.

Radicais livres de oxigênio e exercício: mecanismos de formação e adaptação ao treinamento físico / Oxygen free radicals and exercise: mechanisms of synthesis and adaptation to the physical training

O interesse acerca dos mecanismos de geração e adaptação de radicais livres de oxigênio (RLO) ao exercício aumentou significativamente a partir da demonstração de sua relação com o consumo de oxigênio. Os RLO são formados pela redução incompleta do oxigênio, gerando espécies que apresentam alta reatividade para outras biomoléculas, principalmente lipídios e proteínas das membranas celulares e, até mesmo, o DNA. As injúrias provocadas por estresse oxidativo apresentam efeitos cumulativos e estão relacionadas a uma série de doenças, como o câncer, a aterosclerose e o diabetes. O exercício físico agudo, em função do incremento do consumo de oxigênio, promove o aumento da formação de RLO. No entanto, o treinamento físico é capaz de gerar adaptações capazes de mitigar os efeitos deletérios provocados pelos RLO. Estas adaptações estão relacionadas a uma série de sistemas, dos quais os mais importantes são os sistemas enzimáticos, compostos pela superóxido dismutase, catalase e glutationa peroxidase, e o não enzimático, composto por ceruloplasmina, hormônios sexuais, coenzima Q, ácido úrico, proteínas de choque térmico e outros. Tais adaptações, apesar das controvérsias sobre os mecanismos envolvidos, promovem maior resistência tecidual a desafios oxidativos, como aqueles proporcionados pelo exercício de alta intensidade e longa duração. As técnicas de avaliação de estresse oxidativo, na maioria das vezes, não são capazes de detectar injúria em exercícios de curta duração. Dessa forma, esforços estão sendo feitos para o estudo de esforços físicos realizados por longos períodos de tempo ou efetuados até a exaustão. Novos marcadores de lesão por ação dos RLO estão sendo descobertos e novas técnicas para sua determinação estão sendo criadas. O objetivo deste trabalho é discutir os mecanismos da formação dos RLO e das adaptações ao estresse oxidativo crônico provocado pelo treinamento físico.

Antidiabetic activity of Aegle marmelos and its relationship with its antioxidant properties.

Oxidative stress induced by alloxan has been shown to damage pancreatic beta-cell and produce hyperglycemia in rats. Aegle marmelos leaf extract is being used in Ayurveda as a medicine for diabetes. The present study examined the action of Aegle marmelos against experimental diabetes as well as the antioxidant potential of the drug. A methanolic extract of Aegle marmelos was found to reduce blood sugar in alloxan diabetic rats. Reduction in blood sugar could be seen from 6th day after continuous administration of the extract and on 12th day sugar levels were found to be reduced by 54%. Oxidative stress produced by alloxan was found to be significantly lowered by the administration of Aegle marmelos extract. This was evident from a significant decrease in lipid peroxidation, conjugated diene and hydroperoxide levels in serum as well as in liver induced by alloxan. Catalase and glutathione peroxidase activity in blood and liver were found to be increased from 9th day onwards after drug administration. Superoxide dismutase and glutathione levels were found to be increased only on 12th day. These results indicate that Aegle marmelos extract effectively reduced the oxidative stress induced by alloxan and produced a reduction in blood sugar.

Effects of exogenous vitamin E supplementation on the levels of oxidants and antioxidants in chronic obstructive pulmonary disease.

Oxidative stress has been recognized as a central feature of smoke induced chronic obstructive pulmonary disease (COPD). Imbalance between oxidant and antioxidant enzymes is also an established fact in these patients. But studies in regard to stable COPD patients and effect of vitamin E supplementation are lacking. Thirty patients with COPD were included in the study. Their baseline clinical examination, spirometry, plasma malondialdehyde (MDA), alpha-tocopherol and red blood cell superoxide dismutase (SOD) levels were mea sured. Twenty healthy non-smokers who were matched for age and sex served as controls. All the above parameters were repeated after 12 weeks of supplementation with 400 IU of vitamin E daily. The mean malondialdehyde levels in the patients at baseline were higher than controls (5.91 +/- 1.23 nmol/ml vs 4.55 +/- 1.51 nmol/ml, P = 0 001), so also was plasma alpha-tocopherol levels (P < 0 001), while SOD levels were lower in the patients compared to controls (1692 +/- 259 units g/Hb vs 2451 +/- 131 units g/Hb, P < 0 001). Exogenous vitamin E (400 IU per day) supplementation did not bring about any significant change in plasma alpha-tocopherol and SOD levels. The Pearson s co-efficient of correlation between the levels of MDA, vitamin E, SOD; and spirometric measurements were not significant either on day 1 or after 12 weeks of vitamin E supplementation. The present study shows that initially the plasma lipid peroxide (MDA) levels are high and antioxidants (alpha-tocopherol and SOD) are low in patients with COPD. Exogenous supplementation with vitamin E does not have any significant effect on the spirometric measurements though it brings down the levels of MDA showing attenuation of further damage. However, inclusion of larger number of patients and supple mentation with vitamin E for longer periods may throw more light on free radical injury and protective effects of antioxidants.

Increased exhalation of hydrogen peroxide in healthy subjects following cigarette consumption

CONTEXT: Increased hydrogen peroxide has been described in the expired breath condensate (H2O2-E) of several lung conditions, such as acute respiratory distress syndrome, chronic obstructive pulmonary disease and asthma. This technique has been advocated as being a simple method for documenting airway inflammation. OBJECTIVE: To evaluate H2O2-E in healthy cigarette smokers, and to determine the acute effects of the consumption of one cigarette on H2O2-E levels. TYPE OF STUDY: Prospective, controlled trial. SETTING: A pulmonary function laboratory in a University Hospital. PARTICIPANTS: Two groups of healthy volunteers: individuals who had never smoked (NS; n=10; 4 men; age = 30.6 Ý 6.2 years) and current cigarette smokers (S; n=12; 7 men; age = 38.7 Ý 9.8). None of the volunteers had respiratory symptoms and all showed normal spirometric tests. INTERVENTION: Expired air was collected from all volunteers through a face mask and a plastic collecting system leading into a flask with dry ice and pure ethanol. Samples from the group S were collected twice, before and half an hour after the combustion of one cigarette. MAIN MEASUREMENTS: Expired hydrogen peroxide using the Gallati and Pracht method. RESULTS: The S and NS groups showed comparable levels of H2O2-E at basal conditions [NS = 0.74 muM (DP 0.24) vs. S = 0.75 muM (DP 0.31)]. The smokers showed a significant increase in H2O2-E levels half an hour after the consumption of only one cigarette [0.75 muM (DP 0.31) vs. 0.95 muM (DP 0.22)]. CONCLUSION: The present results are consistent with the concept that smokers increase oxidative stress with elevated production of reactive oxygen species, contributing to the development of smoking-related disorders

Oxidants, anti-oxidants, essential fatty acids, eicosanoids, cytokines, gene/oncogene expression and apoptosis in systemic lupus erythematosus.

Systemic lupus erythematosus (SLE) is an auto-immune disease in which free radicals, eicosanoids, cytokines and nitric oxide seem to play a major role. An increase in the generation of superoxide anion and excess of interleukin-2 (IL-2), tumour necrosis factor (TNF) and pro-inflammatory eicosanoids and a fall in the production of nitric oxide and anti-oxidants such as superoxide dismutase and glutathione peroxidase seems to occur during the active phase of the disease. Thus, an imbalance in the pro-and anti-inflammatory molecules and a change in the delicate balance between the oxidants and anti-oxidants seems to have a vital role in the pathophysiology of SLE. In addition, a defect in the apoptosis of pro-inflammatory T cells may perpetuate the chronic inflammatory process in SLE. Thus, methods designed to suppress the generation of free radicals. IL-1, IL-2 and TNF and of eicosanoids and augment the concentrations of nitric oxide and anti-oxidants and enhance the apoptotic death of the pro-inflammatory T cells may be benefit in the management of SLE. Recent studies suggest that essential fatty acids and their metabolites, whose levels were found to be low in SLE, may restore the balance between pro- and anti-inflammatory molecules, oxidants and anti-oxidants and induce apoptosis of T cell.