The aim of this study was to evaluate and compare the oxidative profiles of three thyroid disorders: Graves' disease (GD), Hashimoto thyroiditis (HT), and papillary thyroid cancer (PTC). Malondialdehyde levels (MDA), glutathione peroxidase (GPx), superoxide dismutase (SOD), and catalase (CAT) activities were examined in the plasma of 52 patients (29 untreated HT, 16 untreated GD, and 7 PTC who underwent surgical therapy). Results were compared with those of 30 healthy controls and among the three groups of patients. The GD, HT, and PTC patients exhibited increased plasma MDA levels and SOD activities compared with the controls (p < 0.05, p < 0.05, and p < 0.001, respectively). CAT activities significantly increased only for the PTC and HT patients (p < 0.001 and p < 0.05, respectively), whereas GPx activities significantly decreased only in the GD and PTC (p < 0.05 and p < 0.01, respectively). The comparison among the three groups of patients has shown increased MDA level and SOD activity for the PTC patients as compared to the GD patients (p < 0.01 and p < 0.001, respectively). Compared with HT, PTC patients exhibited significant higher MDA level, SOD, and CAT activities and a significant lower GPx activity (p < 0.01, p < 0.001, p < 0.05, and p < 0.05, respectively). No significant discrepancies were noted between the GD and HT patients. Our results have clearly shown an oxidative profile that is highly disturbed for the PTC patients as compared to those of autoimmune disorders. Future studies are needed to determine whether or not the oxidative stress has a prognostic value in this pathology.

In the present study, the relationship between total bulk milk somatic cell counts (BMSCC), differential BMSCC (macrophage, lymphocyte, and polymorphonuclear leukocytes), and antioxidant enzymes was investigated. Forty-three samples of bulk milk were selected randomly from eight dairy farms in the region of Sfax (Tunisia) in winter, from November 2005 to February 2006. Bulk milk samples were analyzed for antioxidant enzymes such as catalase, SOD and GSHPx activity and differential SCC. After that, milks were allotted according to their total SCC to: group 1, bulk milk with SCC below 1000 × 10 3 ml −1 ; group 2, bulk milk with SCC from 1000 × 10 3 to 1500 × 10 3 ml −1 ; group 3, bulk milk with SCC above 1500 × 10 3 ml −1 . BMSCC levels ranged from 400 × 10 3 to nearly 4000 × 10 3 ml −1 . Lymphocytes were the predominant cell type in all groups, but their proportion declined with the total BMSCC. Catalase and GSHPx activities were found to be significantly (P < 0.001) correlated with total BMSCC and with the PMN population. In contrast, a weak correlation between the activity of the SOD and total or differential bulk milk somatic cells was observed. It has been suggested that milk cells, especially PMN, could generate a situation of oxidative stress in the mammary gland. Specifically, hydrogen peroxide and hydroxyl radicals were probably the most important reactive oxygen metabolites released by PMN.

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The present study investigates the growth of Dunaliella salina as influenced by cadmium (Cd) contamination. Growth was measured in terms of cell number and chlorophyll a content and was found to decrease with increasing Cd concentration. This metal, which was mainly removed by bioadsorption to cell surfaces (95.34± 3.04 % of total Cd removed), also drastically reduced the soluble and insoluble carbohydrate (0.41±0.01 and 0.81±0.07 pg cell −1 , respectively, for 150 mg Cd L −1 ) concentrations and increased the total metallothioneins protein content (from 0.11±0.02 for the control culture to 3.30±0.2 for 100 mg Cd L −1 ). In addition, the presence of this metal in the medium stimulated the synthesis of some secondary metabolites such as polyphenols, flavonoids, and carotenoids. These compounds had an important role to protect D. salina against the reactive oxygen species (ROS) generated by the presence of Cd in the medium as shown by the increase of the antioxidant capacity of D. salina exposed to Cd.