The effect of occupational exposure to lead on the non-enzymatic antioxidant system.

BACKGROUND: The role of non-enzymatic antioxidants, such as uric acid, albumin, bilirubin, and α-tocopherol, in lead poisoning remains unclear. Therefore, the aim of the study was to explore the association between occupational exposure to lead and non-enzymatic antioxidant concentrations in serum and plasma. MATERIAL AND METHODS: The study population consisted of 278 healthy male employees of lead-zinc plants, with 129 workers classified as having low lead exposure (blood lead level - PbB = 20-39.9 µg/dl) and 149 workers classified as having high lead exposure (PbB = 40-59.8 µg/dl). The control group was composed of 73 healthy male administrative workers. No one from this group had blood lead level or zinc protoporphyrin (ZPP) level greater than normal levels, being 10 µ/dl and 2.5 µg/g of hemoglobin, respectively. In addition to the levels of PbB and ZPP, serum levels of uric acid (UA), albumin, thiol groups of albumin, and bilirubin were determined. The ferric reducing ability of plasma (FRAP) and the plasma level of α-tocopherol were also evaluated. RESULTS: Lead exposure indices were significantly elevated in the examined subgroups as compared with the controls. Serum uric acid levels were significantly elevated in both subgroups, particularly in the group with high exposure. Serum bilirubin concentration was significantly elevated in the group with high exposure compared with the control group, while in the group with low exposure, it showed only a non-significant trend towards an increase. In contrast, ferric-reducing ability of plasma was not significantly greater in the examined subgroups as compared with the control group. Nevertheless, levels of albumin, thiol groups of albumin, and α-tocopherol levels were significantly decreased in the exposed subgroups compared with the control group. CONCLUSIONS: Occupational exposure to lead interferes with the blood non-enzymatic antioxidant system.

Increased H2O2 level in exhaled breath condensate in primary breast cancer patients.

PURPOSE: This study was designed to assess exhaled hydrogen peroxide (H(2)O(2)), blood serum antioxidant capacity, and tumor necrosis factor-alpha (TNFalpha) in primary breast cancer (PBC). METHODS: The study included 34 consecutive, non-smoking PBC patients (aged 62.5 +/- 13.5 at surgery) prior to the treatments, qualified for modified radical mastectomy and not undergoing any adjuvant systemic therapy, and 33 healthy controls. The post surgery pathological assessment included tissue expression of estrogen (ER) and progesterone (PR) receptors, and epidermal growth factor receptor type 2 (HER-2/neu). Exhaled H(2)O(2) was determined fluorometrically in the exhaled breath condensate (EBC). Blood serum antioxidant capacity and TNFalpha levels were assessed with ferric reducing ability of plasma (FRAP) and ELISA immunoassay, respectively. RESULTS: In PBC patients, 10 ER, 11 PR, and 9 HER-2/neu positive tumors were identified and HER-2/neu score was 2+ in 20% of all tumors. Median (Me) H(2)O(2) was increased up to 0.44 microM (interquartile range IR: 0.20-1.25 microM) compared with healthy control of 0.36 microM (IR: 0.12-0.48 microM; p < 0.05). The H(2)O(2) concentration in EBC was significantly correlated (tau = 0.27; p = 0.03) and increased in cases with nodal metastases (n = 12; p = 0.04). Serum TNFalpha was increased up to 51.7 +/- 21.0 pg/ml compared with controls 17.2 +/- 3.65 pg/ml (p < 0.05). FRAP was increased to 1.41 +/- 0.37 mM Fe(2+) compared with control 1.19 +/- 0.17 mM Fe(2+); (p = 0.006). CONCLUSIONS: This is the first study to demonstrate increased H(2)O(2) in exhaled breath condensate in patients with localized breast malignancy and its relation with clinical severity.

A morphological and cytochemical study of the interaction between Paracoccidiodes brasiliensis and neutrophils.

Paracoccidioidomycosis is a systemic granulomatous disease caused by the dimorphic fungus Paracoccidioides brasiliensis. It is the most prevalent systemic mycosis of Latin America and 80% of the reported cases are from Brazil. Because of the great number of neutrophils found in the P. brasiliensis granuloma, studies have been done to evaluate the role of these cells during the development of the infection. Scanning and transmission electron microscopy of thin sections showed that the neutrophils ingest yeast cells through a typical phagocytic process with the formation of pseudopodes. The pseudopodes even disrupt the connection established between the mother and the bud cells. Neutrophils also associate to each other, forming a kind of extracellular vacuole where large yeast cells are encapsulated. Cytochemical studies showed that once P. brasiliensis attaches to the neutrophil surface, it triggers a respiratory burst with release of oxygen-derived products. Attachment also triggers neutrophils degranulation, with release of endogenous peroxidase localized in cytoplasmic granules. Together, these processes lead to killing of both ingested and extracellular P. brasiliensis.