Antioxidant enzymes activities and bilirubin level in adult rat treated with lead

Lead toxicity is closely related to its accumulation in several tissues and its interference with bioelements, whose role is critical for several biological processes. Recently, oxidative stress has been proposed as a possible mechanism involved in lead toxicity. This study was carried out to investigate the effect of dose-dependent lead exposure on haematological and oxidative stress parameters. Adult male 'Wistar' rats (150-200 g) were divided into three groups: group [Pb 5] and group [Pb 15] received respectively 5 mg Pb(2+) (n=16) and 15 mg Pb(2+)/kg b.w. (n=16) as lead acetate solution i.p. for a period of seven days. Group [T] (n= 16) served as control and received 15 mg Na(+)/kg b.w. as sodium acetate solution i.p. for the same period. All animals were sacrificed 24 h after the last injection. Blood superoxide dismutase (SOD) and blood glutathione peroxidase (GPx) activities and plasma bilirubin level were measured. Liver was quickly excised for the estimation of alteration in lipid peroxidation indices (MDA). Lead exposure induces, in both treated groups, a marked decline in haematocrit and haemoglobin levels (p<0.01) when compared to control. The results show also a significant decrease (p<0.01) in SOD activity, but only in group [Pb 15]. SOD activity did not decrease in group [Pb 5] in comparison with control (p>0.05). However, lead exposure caused a light increase in GPx activity in group [Pb 15], which remains non-significant (p>0.05) compared to control. Group [Pb 5] did not record significant changes in the activity of GPx. Lead exposure for a period of seven days resulted in a significant (p<0.05) increase in bilirubin level in group [Pb 15] compared to control. The bilirubin level from rats of group [Pb 5] did not reach a statistical significance. Changes in liver MDA content in lead-exposed rats from [Pb 5] and [Pb 15] groups did not reach a statistical (p<0.05) significance. It is concluded that lead induces oxidative stress in a dose-dependent manner. No dose-dependent response was observed in blood GPx activity and liver MDA content. These results could be due to the short duration of the treatment.     

Steroid 21-hydroxylase gene mutational spectrum in 50 Tunisian patients: Characterization of three novel polymorphisms

Congenital adrenal hyperplasia (CAH) is an autosomal recessive disease of steroid biosynthesis in humans. More than 90% of all CAH cases are caused by mutations of the 21-hydroxylase gene (CYP21A2), and approximately 75% of the defective CYP21A2 genes are generated through an intergenic recombination with the neighboring CYP21A1P pseudogene. In this study, the CYP21A2 gene was genotyped in 50 patients in Tunisia with the clinical diagnosis of 21-hydroxylase deficiency. CYP21A2 mutations were identified in 87% of the alleles. The most common point mutation in our population was the pseudogene specific variant p.Q318X (26%). Three novel single nucleotide polymorphism (SNP) loci were identified in the CYP21A2 gene which seems to be specific for the Tunisian population. The overall concordance between genotype and phenotype was 98%. With this study the molecular basis of CAH has been characterized, providing useful results for clinicians in terms of prediction of disease severity, genetic and prenatal counseling.     

Catalase and Lipid Peroxidation Values in Serum of Tunisian Patients with Pemphigus Vulgaris and Foliaceus

Pemphigus is an autoimmune disorder resulting from the interaction between autoantibodies and desmoglein. Oxidative stress seems to be responsible for the onset/aggravation of many human diseases. Actually, it is considered as one of the several factors for the etiopathogenesis of pemphigus. The present study aims to evaluate the oxidative state in the sera of pemphigus vulgaris and pemphigus foliaceus patients by assessing lipid peroxidation, proteins oxidation, and antioxidant enzyme activity. This study included 36 pemphigus vulgaris and 42 pemphigus foliaceus patients as well as a group of controls consisting of 78 healthy volunteers. Malondialdehyde levels (p?<?0.001) and catalase activity (p?<?0.001) are higher in both groups of patients than in the control group. The two groups of patients showed a nonsignificant decrease in the thiol groups compared with the healthy one. A nonsignificant difference was shown between pemphigus vulgaris and pemphigus foliaceus patients, except for the catalase which shows an increase in the pemphigus vulgaris group. We have also found significant correlations between serum oxidative stress marker levels and serum anti-desmoglein antibody levels in the two pemphigus groups. These findings underline the implication of oxidative stress in the physiopathology of pemphigus by the increase in the autoantibodies?? reactivity.     

Epstein-Barr virus induces an oxidative stress during the early stages of infection in B lymphocytes, epithelial, and lymphoblastoid cell lines

The study investigates the direct effect of Epstein-Barr virus infection on the oxidative profile of in vitro cultivated human cells. For this purpose, a panel of human EBV target cells presenting heterogeneity in their cellular and culture types (epithelial cells or lymphocytes; primary culture or continuous cell culture) was selected. These cells are purified human B lymphocytes, DG75, 293, and HepG2 cell lines. The oxidative stress was evaluated during the early stages of infection (2, 12, and 24 h) by measuring malondialdehyde, the end product of the lipid peroxidation, as well as the activities of two antioxidant enzymes: catalase and superoxide dismutase. The obtained results were compared with those of the untreated cells and the K562 cell line which has no interaction with EBV. The incubation of the different target cells with EBV induced an oxidative stress in the purified B lymphocytes, DG75, and 293, but not in HepG2 and K562. This oxidative stress was highlighted by an increase in MDA level (P < 0.05), which began 2 h after the addition of the virus and persisted after 12 and 24 h. Simultaneously, a decrease in catalase and superoxide dismutase activities was observed (P < 0.05), suggesting an alteration of the molecular mechanisms promoting cellular resistance to reactive oxygen species (ROS). The efficiency of EBV infection, assessed by viral DNA PCR amplification, was confirmed in 293 and DG75 but not in HepG2, which was in total concordance with their oxidative profiles. In conclusion, the EBV infection of B and epithelial cells leads to the establishment of an oxidative stress which can play a key role during the viral transformation.     

Phytoremediation of domestic wastewater using a hybrid constructed wetland in mountainous rural area

The purpose of this study is to evaluate the efficiency of hybrid constructed wetlands (HCWs) in a rural mountainous area. The experiment was set up in small rural community named Tidili within the region of Marrakech, Morocco. The wastewater treatment plant was composed of three vertical flow constructed wetlands (VFCWs) working in parallel, followed by two parallel horizontal-subsurface flow constructed wetlands (HFCWs), with hydraulic loading rates of 0.5 and 0.75 m³/m².d, respectively. The two units were planted with Phragmites australis at a density of 4 plants/m². Wastewater samples were collected at the inlet of the storage tank and at the outlet of the whole system (VFCWs, HFCWs) stages. The main removal percentages of total suspended solids (TSS), biochemical oxygen demand measured in a 5-day test (BOD₅), chemical oxygen demand (COD), total nitrogen, and total phosphorus were respectively 95%, 93%, 91%, 67%, and 62%. The system showed a very high capacity to remove total coliforms, fecal coliforms, and fecal streptococci (4.46, 4.31, and 4.10 Log units, respectively). Artificial neural networks (ANNs) were used to model the quality parameters (TSS, BOD₅, COD) and total coliforms and fecal streptococci. Based on the obtained results, the ANN model could be considered as an efficient tool to predict the studied phytoremediation performances using HCWs.     

Microparticle miRNAs as Biomarkers of Vascular Function and Inflammation Response to Aerobic Exercise in Obesity?

Objective

This study aimed to explore the role of nine microRNAs (miRNAs) in microparticles (MPs) on the efficacy of aerobic exercise in the regulation of inflammation and vascular function in obesity.

Methods

Sedentary women with normal weight (n = 6, BMI < 25 kg/m²) and women with obesity (n = 9, BMI > 30 kg/m²) were recruited at F. Hached Hospital (Sousse, Tunisia) and enrolled in an 8‐week aerobic program. Vascular function was assessed using laser Doppler flowmetry/iontophoresis, circulating MPs by flow cytometry, miRNAs by real‐time polymerase chain reaction, and inflammation by ELISA, before and after exercise.

Results

Women with obesity presented with high prevalence of cardiovascular risk factors and a higher circulating MP level compared with healthy subjects. The MP miRNA profile was significantly different in the two groups. Exercise reduced BMI and inflammation in both groups and significantly improved endothelial‐dependent response (acetylcholine cutaneous vascular conductance) for healthy subjects, with a trend for women with obesity. Circulating MP level was increased after exercise, and miRNA expression was differentially modulated in both populations. Pearson analysis revealed a correlation between MPs miR‐124a and miR150 and adiponectin, TNFα, or IL‐6 levels.

Conclusions

The relation between MPs and miRNA profile, inflammation, vascular function, and exercise is of particular interest for defining “miRNA biomarker signature” in patients with cardiovascular disease who are potentially susceptible to respond to exercise.

     

CHARACTERIZATION OF HUMAN RECOMBINANT INTERLEUKIN 2 BINDING TO HEPARIN AND HEPARAN SULFATE USING AN ELISA APPROACH

We have developed an enzyme-linked immunosorbent assay (ELISA) approach for the study of interactions between cytokines and glycosaminoglycans. This involves, as solid phase, a synthetic heparin–bovine serum albumin (BSA) complex in which the heparin is coupled via its reducing terminus to the protein using sodium cyanoborohydride. We have investigated the sensitivity and specificity of this experimental technique, employing antithrombin (AT III) and fibroblast growth factor 2 (FGF-2) as well-characterized heparin binding proteins. Using this ELISA method, we have established that human recombinant interleukin (IL-2) binds to heparin in a concentration-dependent manner. Soluble heparin competes for the binding of IL-2 to the complex with 50% inhibition at 5 μg/ml. This IC₅₀value provides an estimate of the binding constant of around 0.5 μM. This value is at least two orders of magnitude larger than that for the binding of IL-2 to its dimeric and trimeric cell surface receptors, but similar to that for binding to the IL-2 receptor β polypeptide acting alone. Our ELISA shows that in addition to soluble heparin, fuciodan also competes for IL-2 binding, but chondroitin sulfate and dermatan sulfate are inactive. Of six heparan sulfates tested, only one highly sulfated preparation competed for IL-2. The interaction between IL-2 and heparin-like glycosaminoglycans is likely to be an important mechanism for retaining IL-2 close to its sites of secretion, thus giving rise to localized concentration gradients in the tissues.     

Glia Modulate NMDA-Mediated Signaling in Primary Cultures of Cerebellar Granule Cells

Abstract: Excessive activation of N-methyl-d -aspartate (NMDA) receptor channels (NRs) is a major cause of neuronal death associated with stroke and ischemia. Cerebellar granule neurons in vivo, but not in culture, are relatively resistant to toxicity, possibly owing to protective effects of glia. To evaluate whether NR-mediated signaling is modulated when developing neurons are cocultured with glia, the neurotoxic responses of rat cerebellar granule cells to applied NMDA or glutamate were compared in astrocyte-rich and astrocyte-poor cultures. In astrocyte-poor cultures, significant neurotoxicity was observed in response to NMDA or glutamate and was inhibited by an NR antagonist. Astrocyte-rich neuronal cultures demonstrated three significant differences, compared with astrocyte-poor cultures: (a) Neuronal viability was increased; (b) glutamate-mediated neurotoxicity was decreased, consistent with the presence of a sodium-coupled glutamate transport system in astrocytes; and (c) NMDA- but not kainate-mediated neurotoxicity was decreased, in a manner that depended on the relative abundance of glia in the culture. Because glia do not express NRs or an NMDA transport system, the mechanism of protection is distinct from that observed in response to glutamate. No differences in NR subunit composition (evaluated using RT-PCR assays for NR1 and NR2 subunit mRNAs), NR sensitivity (evaluated by measuring NR-mediated changes in intracellular Ca²⁺ levels), or glycine availability as a coagonist (evaluated in the presence and absence of exogenous glycine) were observed between astrocyte-rich and astrocyte-poor cultures, suggesting that glia do not directly modulate NR composition or function. Nordihydroguaiaretic acid, a lipoxygenase inhibitor, blocked NMDA-mediated toxicity in astrocyte-poor cultures, raising the possibility that glia effectively reduce the accumulation of highly diffusible and toxic arachidonic acid metabolites in neurons. Alternatively, glia may alter neuronal development/phenotype in a manner that selectively reduces susceptibility to NR-mediated toxicity.     

Lipid Peroxidation and Antioxidant System in the Tumor and in the Blood of Patients with Nasopharyngeal Carcinoma

Reactive oxygen species play a key role in cancer development by inducing and maintaining the oncogenic phenotypes of cancer cells. In this study, we examined lipid peroxidation and antioxidant enzymes activities in the blood and in the tumor of nasopharyngeal carcinoma patients. Plasma malondialdehyde, conjugated dienes, erythrocytes catalase, and superoxide dismutase activities have been measured in 30 untreated nasopharyngeal carcinoma patients and 30 controls on one hand. On the other hand, tumor malondialdehyde level, catalase, and superoxide dismutase activities have been measured in five nasopharyngeal carcinoma patients and compared with four controls. The lipid peroxidation was confirmed in the plasma by the high levels of malondialdehyde and conjugated dienes (p?<?0.001, respectively). Additionally, significantly higher concentrations of malondialdehyde were found in biopsies compared to the control group (p?<?0.001). In erythrocytes, superoxide dismutase activity was higher in patients than in controls (p?<?0.05), while it was unchanged in the tumor (p?>?0.05). Both erythrocytes and tumor catalase activities were significantly lower in patients than in controls (p?<?0.001, respectively). Statistical studies have shown a positive correlation between malondialdehyde level and IgA antibodies level against Epstein–Barr virus capsid antigen (p?<?0.05). In conclusion, we reported the presence of an oxidative stress in the blood and in the biopsies of nasopharyngeal carcinoma patients where Epstein–Barr virus seems to play a role.