Effect of sodium selenite treatment on platelet aggregation of streptozotocin-induced diabetic rats

Introduction: There is a well-known association between diabetes and atherosclerosis. Platelets are involved in the development of atherosclerotic vascular diseases and play a key role in atherosclerotic complications. Diabetes mellitus is related to alteration in the homeostasis of selenium and the protective role of selenium against lipid peroxidation in diabetes is reported. In the present study, thrombin-induced platelet aggregation and thromboxane A₂ (TxA2) formation in diabetes and the effect of sodium selenite were evaluated. Materials and methods: Diabetes was induced by intraperitoneal injection of streptozotocin (STZ) in Wistar rats (n=21). Thirty of them were used as control rats. A week after streptozotocin injection, 11 of the control rats and 12 of the diabetics were injected with 5 μmol/kg/day of sodium selenite for 4 weeks. Thrombin-induced aggregation of the platelets was evaluated by optical technique. Thromboxane B₂ (TxB2), TxA2 metabolite, was measured by enzyme-linked immunoassay (EIA) in thrombin-induced platelets. Results and conclusion: The platelet aggregation and TxB2 level increased in diabetic rats. Sodium selenite reversed the increase in platelet aggregation and TxB2 and caused a small but significant (p<0.05) decrease in the glucose level. The hyperaggregability of platelets in STZ-induced diabetic rats was thought to be related to the enhanced TxA2 formation of platelets. Increase in TxA2 formation implies lipid peroxidation. Sodium selenite decreased the TxA2 formation. Besides its antioxidative effect, further studies are needed to establish the insulin-like effect of selenite because of a small decrease in blood glucose.     

Impairment of antioxidant enzymes, lipid peroxidation and 8-oxo-2'-deoxyguanosine in advanced epithelial ovarian carcinoma of a Spanish community

In the present study, we describe the changes of antioxidant enzyme activities and other oxidative stress-related parameters in a mediterranean cohort of women affected with epithelial ovarian carcinoma (EOC). For that purpose, the most representative enzymatic activities, such as superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) and the oxidized/reduced glutathione (GSSG/GSH) ratio have been analyzed in tumor tissue biopsies and compared with the normal tissue of the same patient. As oxidation products, the levels of malondialdehyde (MDA) as an indication of lipid peroxidation, and the DNA damaged base 8-oxo-2'-deoxyguanosine (8-oxo-dG) have been also measured. Advanced EOC show reduced levels of SOD and CAT, while that of GPx is increased when compared with non-neoplastic tissue. The levels of GSH are increased giving as a result a reduction of the oxidative stress marker GSSG/GSH ratio comparing normal ovarian tissue with tumor tissue. In addition, the oxidation products MDA and 8-oxo-dG are significantly increased in tumor tissue, suggesting a shift of oxidative metabolisms towards a pro-oxidation state and potential gene instability in malignant ovary cells. The possible implication of the redox changes and DNA damage in tumor development is discussed.     

Protection against radiation-induced oxidative stress in cultured human epithelial cells by treatment with antioxidant agents

PURPOSE: To evaluate the protective effects of antioxidant agents against space radiation-induced oxidative stress in cultured human epithelial cells. METHODS AND MATERIALS: The effects of selected concentrations of N-acetylcysteine, ascorbic acid, sodium ascorbate, co-enzyme Q10, alpha-lipoic acid, l-selenomethionine, and vitamin E succinate on radiation-induced oxidative stress were evaluated in MCF10 human breast epithelial cells exposed to radiation with X-rays, gamma-rays, protons, or high mass, high atomic number, and high energy particles using a dichlorofluorescein assay. RESULTS: The results demonstrated that these antioxidants are effective in protecting against radiation-induced oxidative stress and complete or nearly complete protection was achieved by treating the cells with a combination of these agents before and during the radiation exposure. CONCLUSION: The combination of antioxidants evaluated in this study is likely be a promising countermeasure for protection against space radiation-induced adverse biologic effects.     

金钗石斛中的菲类和木脂素类成分及其抗氧化作用

研究金钗石斛茎中的抗氧化活性成分，并探讨它们的构效关系。综合运用现代色谱学和光谱学方法对金钗石斛60％乙醇提取物中的化学成分进行分离鉴定，采用DPPH自由基清除法评价化合物的抗氧化活性。从金钗石斛的活性部位中分离得到5个菲类化合物和4个木脂素类化合物，它们的结构鉴定为流苏菲（1），毛兰菲（2），4-甲氧基菲-2，7-二醇（3），2,5-二羟基-4，9-二甲氧基菲（4），3，7-二羟基-2，4-二甲氧基菲（5），丁香脂素（6），松脂素（7），5′-甲氧基松脂素（8），鹅掌揪树脂醇-A（9）。化合物2和6对DPPH自由基清除活性强于Vc；化合物3，4，5，7，8和9的活性弱于Vc，但强于BHT。所有化合物均为首次报道从金钗石斛中分离得到，化合物3，4和9为首次报道从石斛属植物中分离得到。在DPPH自由基清除法中，酚羟基的邻位存在具有供电作用的甲氧基时对菲类和木脂素类化合物的抗氧化活性具有积极的作用。     

Hypolipidemic and hepatoprotective effects of flax and pumpkin seed mixture rich in ω-3 and ω-6 fatty acids in hypercholesterolemic rats

Flax and pumpkin seeds are a rich source of unsaturated fatty acids, antioxidants and fibers, known to have anti-atherogenic and hepatoprotective activities. These effects were evaluated in Wistar rats fed with 1% cholesterol diet. The study was performed on 30 male rats divided into three groups: a control group (CD), CD-chol group fed diet with 1% cholesterol and MS-chol group fed diet enriched with flax and pumpkin seed mixture. In CD-chol group, total cholesterol TC, triacylglycerol TG in plasma and liver, plasma LDL-C, atherogenic index AI and LDL/HDL ratio significantly increased. In MS-chol group lipid parameters decreased significantly, plasma and liver fatty acid composition showed an increase of PUFAs (ALA and LA), and MUFAs (oleic and eicosaenoic acid) and a decrease of SFA (palmitic and stearic acid). In plasma and liver of MS-chol group, malondialdehyde levels decreased and the efficiency of antioxidant defense system was improved compared to CD-chol group. Liver histological sections showed lipid storage in hepatocytes of CD-chol group and an improvement was noted in MS-chol group. Our results suggested that flax and pumpkin seed mixture had anti-atherogenic and hepatoprotective effects which were probably mediated by unsaturated fatty acids present in seed mixture.     

复印作业对人体氧化和过氧化的影响

目的探讨复印作业对人体氧化和过氧化的影响。方法检测１０４例复印作业者和１００例健康成人血浆ＶｉｔＣ、ＶｉｔＥ、β－胡萝卜素（β－ＣＡＲ）、过氧化脂质（ＬＰＯ）含量及红细胞超氧化物歧化酶（ＳＯＤ）、过氧化氢酶（ＣＡＴ）、谷胱甘肽过氧化物酶（ＧＳＨ－Ｐｘ）活力和ＬＰＯ含量。结果与健康成人组比较，复印作业组的血浆ＶｉｔＣ、ＶｉｔＥ、β－ＣＡＲ和红细胞ＳＯＤ、ＣＡＴ、ＧＳＨ－Ｐｘ平均值皆显著降低（Ｐ＜０．０１），而血浆及红细胞ＬＰＯ平均值明显升高（Ｐ＜０．０１），３种不同机型复印作业组各指标平均值间皆差异无显著性（Ｐ＞０．０５），配备通风装置组与未配备通风装置组各指标平均值间差异皆有显著性（Ｐ＜０．０１），复印作业工龄与各指标间均呈一定程度的直线相关（Ｐ＜０．０２～０．０００１）。结论复印从业人员体内氧化和过氧化反应加剧     

Role of oxidant injury in the pathogenesis of neonatal lung disease

Bronchopulmonary dysplasia (BPD) is a chronic lung disease that develops in newborn infants treated with oxygen and mechanical ventilation for a primary lung disorder. With significant improvements in survival of many critically ill infants, BPD has become an extremely important complication of newborn intensive care. The pathogenesis of BPD is complex and involves a variety of causative factors. However, increasing evidence has suggested that an oxidative insult could be an extremely important component of the injury process. Premature infants are especially sensitive to oxidant injury since they are exposed to supraphysiological concentrations of oxygen at birth while endogenous antioxidant enzyme activity may be relatively deficient.
Conclusion : Superoxide dismutase is an antioxidant enzyme that has been shown in numerous basic and clinical studies to protect cells against oxidant injury.     

Dietary oxygen radical absorbance capacity as a predictor of bone mineral density

Bone mineral density (BMD) was measured at the middle phalange of the non-dominant hand by dual x-ray absorptiometry in a random sample of 123 women aged 19 to 63 years. Monthly intake of foods with high Oxygen Radical Absorbance Capacity (ORAC) was obtained using a Food Frequency Questionnaire (FFQ), ORAC scores were calculated, and lifestyle factors were used as confounding variables. After adjusting for age, supplement use, HRT status, physical activity, calcium intake, and ORAC intake, BMD was not predicted by ORAC. We conclude that more research is needed to measure ORAC for all free radicals in all commonly consumed fruits, vegetables, and teas in order to improve the usefulness of the FFQ in calculating approximate dietary ORAC. At this time, the potential of ORAC as a reliable predictor of health remains largely unknown, however, using currently available ORAC information, it cannot be considered a predictor of BMD.     

Malignant diseases among patients with multiple sclerosis

Summary The frequency of malignant diseases among 1866 living and 340 deceased multiple sclerosis (MS) patients was investigated in Finland. The study revealed a low prevalence (0.64%) and mortality (0.07%) rate of cancer among MS patients. The difference between MS patients and general population was significant. The highest rate was found in the group from 40 to 49 years while in the general population the rate of cancer among MS patients tended to fall after the age of 50. The possible role of selenium, one of the antioxidants in the pathogenesis of MS and cancer, is discussed because recent data have shown a very high negative correlation between selenium and cancer death rates.

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Zusammenfassung Die Malignomenfrequenz bei 1866 lebenden und 340 verstorbenen Multiple-Sklerose (MS)-Patienten wurde in Finnland untersucht. Dabei wurde eine niedrige Prävalenz-(0.64%) und Mortalitätsrate (0.07%) für Karzinom ermittelt. Der Unterschied zwischen den MS-Patienten und der Normalbevölkerung war signifikant. Die höchste Inzidenzrate war in der Altersgruppe von 40 bis 49 Jahren festzustellen. Anders wie bei der Normalbevölkerung nahm bei den MS-Patienten die Karzinomfrequenz nach dem fünfzigsten Lebensjahr ständig ab. Die mögliche Rolle Seleniums, eines Antioxydants, in der Pathogenese von MS und Karzinom wurde diskutiert, denn neue Ergebnisse haben eine hohe negative Korrelation zwischen Selenium und Karzinommortalität erwiesen.