Removal of selenite using ‘waste’ Fe(III)/Cr(III) hydroxide: Adsorption kinetics and isotherms

Removal of selenite [Se (IV)] from aqueous solution on to industrial solid ‘waste’ Fe(III)/Cr(III) hydroxide as adsorbent was investigated in the present article. Maximum adsorption was found to be at pH 4.0. Pretreated Fe(III)/Cr(III) hydroxide was found to be more efficient for the removal of selenite compared to untreated adsorbent. Langmuir and Freundlich isotherms have been studied. The Langmuir adsorption capacity (Q ₀) of the pretreated and untreated adsorbents was found to be 15.63 and 6.04?mg?g^?1, respectively. The adsorption process fit into the second-order kinetics. Thermodynamic parameters show that the adsorption process is spontaneous and endothermic in the temperature range 32 to 60°C. Coexisting anions vanadate and phosphate significantly affect the adsorption of selenite for both the pretreated and untreated adsorbents. Molybdate, thiocyanate, sulphate, nitrate and chloride do not significantly affect the removal of selenite for pretreated adsorbent.     

Fatty acid composition of marine macroalgae from the Black Sea and Dardanelles

The fatty acid (FA) composition was determined in 14 species of marine macroalgae belonging to the Chlorophyta, Phaeophyta and Rhodophyta, which were collected from ?ile in the Black Sea and Kepez in the Dardanelles. Generally, polyunsaturated FAs and monounsaturated FAs were major components (50–77%). Total saturated FAs ranged from 22% to 50%, with 16?:?0 as the most abundant saturate (32–38%). Two samples of Cystoseira barbata collected from a different station had some differences from each other in their contents of 18?:?2n-6 and 18?:?3n-3 and in the 18?:?2n-6/20?:?4n-6 ratios. Green algal species had a significantly higher proportion of unsaturated FAs and a significantly lower proportion of saturated FAs than the red and brown algae. The amount of n-3 FAs was significantly higher in Ulva rigita, Chaetomorpha linum, Enteromorpha linza and Gracilaria verrucosa (8.88, 6.44, 5.31 and 5.24, respectively).     

Levels of plasma B-esterases and glutathione-S-transferase activities in three South American toad species

We determined the normal levels of butyrylcholinesterase (BChE), carboxylesterase (CbE), and glutathione S-transferases (GST) activities in three South American toad species in order to establish reference values for field pesticide monitoring purposes. Interspecies variations in B-esterase and GST activities were examined according to body mass. In addition, comparative inhibition of BChE and CbE activities using malaoxon, and chemical reactivation of malaoxon-inhibited BChE activity using pyridine-2-aldoxime methochloride (2-PAM) were investigated. Bufo fernandezae had average activity values for BChE: 17.31 mmol min^?1 ml^?1; CbE: 621.49 nmol min^?1 ml^?1 and GST: 1.94 mmol min^?1 ml^?1 while B. arenarum enzymatic average activities were BChE: 9.51 mmol min^?1 ml^?1; CbE: 270.07 nmol min^?1 ml^?1, and GST: 1.59 mmol min^?1 ml^?1; finally Bufo schneideri had enzymatic mean values of BChE: 2.08 mmol min^?1 ml^?1; CbE: 301.95 nmol min^?1 ml^?1, and GST: 1.60 mmol min^?1 ml^?1. Moreover, we found an allometric relationship between plasma BChE and CbE activities and body size for the three toad species. We suggest that B. fernandezae would be the species with a higher tolerance capacity to organophosphorous insecticides compared to the other toad species, while B. schneideri may be the most vulnerable toad species to field pesticide exposure, although some other factors (e.g., brain AChE sensitivity or pesticide metabolism by phosphotriesterases) should be also taken into account. The malaoxon-inhibited BChE activity of the three toad species was reactivated in the presence of 2-PAM, and it is recommended as a specific and sensitive methodology in the assessment of field exposure to OP insecticides together to compare BChE activity levels between OP-exposed and nonexposed individuals.     

Toxicological effects of mouse diet contaminated with tributyltin on the immune and neurological systems of C57BL/6 mice

Organotin compounds, widely used as antifouling agents, are known to bioaccumulate in the food chain. Among organotin compounds, tributyltin (TBT), a toxic and widespread contaminant, has become a serious factor in environmental pollution and is suspected of being immunotoxic in animals. The purpose of this study was to assess the effects of 80 µg of TBT per kilogram of body weight (kg bw), provided in food, on the immune and neurological systems of C57Bl/6 mice. Data showed that TBT increased the proliferation of T and B lymphocytes in both adult and juvenile female and juvenile male mice, but that it decreased the proliferation of both T and B lymphocytes in adult male mice. The macrophages activity in female and male juvenile mice was higher than in adults of both sexes. The natural killer cytotoxic activity was also increased in juvenile and adult males and females compared to the control groups. In the brain, we observed the presence of TBT in the hippocampus, the striatum, the cortex, and the cerebellum in both the male and female groups. The highest levels were observed in the cortex of females and males, while the lowest levels were found in the cerebellum. TBT also induced an increase in the levels of the antioxidant glutathione (GSH) in the striatum, the hippocampus and in cortical structures but not in the cerebellum where the levels of TBT are lower. Our findings indicate that TBT modulated the immune and nervous systems causing endocrine and nervous perturbations.     

Gulf War agents trigger discrete transcriptional changes in human neuronal cells

Reports on Gulf War illness (GWI) implicated the use of the pesticide permethrin (PER), and the insect repellent N,N-diethyl-m-toluamide (DEET), in its etiology, as well as pyridostigmine bromide (PB), which was given as a prophylactic treatment against nerve agent exposure. Using Affymetrix microarrays the genomic response of human neuronal SHSY-5Y cells to 10 days of exposure to these agents was characterized and profiles of gene modulation unique to each treatment were demonstrated. In particular, a significantly greater impact of PER was observed compared to the other treatments. The Ingenuity Pathway Analysis knowledgebase was used to analyze the genomic datasets and attribute functional consequences to the effects of related genes, which were significantly up- or down-regulated in response to different treatments. Canonical pathways shown to be significantly modulated at the genomic level in response to exposure included cellular mechanisms, which might contribute to the clinical presentation in GWI patients and thus be targeted for further investigation as potential targets for therapeutic intervention.     

Absence of metallothionein 3 expression in breast cancer is a rare but favorable marker that is under epigenetic control

Cadmium (Cd²⁺), a known carcinogen, mimics the effects of estrogen in the uterus and mammary gland suggesting its possible involvement in the development and progression of breast cancer. This lab showed through analysis of a small set of archival human diagnostic specimens that the third isoform of the classic Cd²⁺ binding protein metallothionein (MT-3) is not expressed in normal breast tissue, but is expressed in some breast cancers and that expression tends to correlate with a poor disease outcome. The goals of this study were to verify that overexpression of MT-3 in a large set of archival human diagnostic specimens tends to correlate with poor disease outcome and define the mechanism of MT-3 gene regulation in the normal breast epithelial cell. The results showed that MT-3 was expressed in approximately 90% of all breast cancers and was absent in normal breast epithelium. The lack of MT-3 staining in some cancers correlated with a favorable patient outcome. High frequency of MT-3 staining was also found for in situ breast cancer suggesting that MT-3 might be an early biomarker for breast cancer. The study also demonstrated that the MCF-10A cell line, an immortalized, non-tumorigenic model of human breast epithelial cells, displayed no basal expression of MT-3, nor was it induced by Cd²⁺. Treatment of the MCF-10A cells with the demethylation agent, 5-aza-2′-deoxycytidine, or the histone deacetylase inhibitor, MS-275, restored MT-3 mRNA expression. It was also shown that the MT-3 metal regulatory elements are potentially active binders of protein factors following treatment with these inhibitors suggesting that MT-3 expression may be subject to epigenetic regulation.     

The status of heavy metal levels in a Ramsar site,Kuala Gula bird sanctuary: the impact of the anthropogenic inputs

Distributions of Cd, Cu, Pb, and Zn in the surface sediments from two sites of the Kuala Gula Bird Sanctuary, Malaysia were monitored for a period of 6 months from October 2006 to March 2007. In December 2006, the concentration of Zn in one location was significantly (p??1) than the other metals at both sites, but in the oxidizable organic fraction it was highest at both sites during October; with mean concentrations of 18?mg?kg^?1 at both locations. In the acid-reducible fraction, high concentrations of Pb (2.3?mg?kg^?1) were detected at station 2 in February 2007, being highest among all four metals at both stations. The acid-reducible fraction found in Pb ranged from 0.10% to 3.1% in both stations. Percentages ranging from 51% to 96% were observed for all four metals in the resistant fraction throughout the sampling period. These results indicate low contributions from anthropogenic sources. The findings constitute a baseline data archive for future reference.     

Pharmacokinetics of [14C]-atrazine in rhesus monkeys,single-dose intravenous and oral administration

This is the first study regarding the pharmacokinetics of [¹⁴C]-atrazine conducted with rhesus monkeys. The animals received one dose (0.25 mg) intravenously (IV) or three doses (1, 10, or 100 mg) orally. Plasma, urine, and feces were collected at defined times up to 7 days post-dosing. Sample radioactivity was measured to determine the mass equivalent. IV administered [¹⁴C]-atrazine disappeared rapidly from blood, with an elimination half-life of about 5.5 ± 1.1 h. The pharmacokinetic profiles of [¹⁴C]-atrazine following oral administration at the three dose levels show that kinetic parameters such as AUC and C _max are linearly correlated with the dose. Seven days after dosing, urinary and fecal excretion of [¹⁴C]-atrazine reached 99% of total administered dose in the IV group and 91–95% in the three oral dose groups. In the IV-administered monkeys, approximately 85% of the dose was excreted in urine and 12% in feces. In three oral dose groups, urinary and fecal radioactivity recoveries approximated 57% and 21%, 58% and 25%, and 53% and 35%, respectively. More than 50% of the total urinary excreted radioactivity was found within the first 24 h after dosing. In conclusion, the principal elimination of [¹⁴C]-atrazine, IV and orally administered, is via urine. The oral bioavailability was 60% or higher. There was a significant linear correlation between administered oral dose and plasma concentration. Overall oral dose accountability ranged from 91% to 95%. Data generated may be useful in the risk assessment of human exposure to environmental atrazine contamination.     

Early murine immune responses from endotracheal exposures to biotechnology-related Bacillus strains

An immunology-based in vivo screening regime was used to assess the potential pathogenicity of biotechnology-related microbes. Strains of Bacillus cereus (Bc), Bacillus subtilis (Bs), Bacillus thuringiensis (Bt), and Bt commercial products (CPs) were tested. Balb/c mice were endotracheally instilled with purified spores, diluted CP, or vegetative cells (VC) (live or dead). Exposed mice were evaluated for changes in behavioral and physical symptoms, bacterial clearance, pulmonary granulocytes, and pulmonary and circulatory pyrogenic cytokines (interleukins (IL)-1β, IL-6 and tumor necrosis factor (TNF)-α), as well as acute phase biomarkers (fibrinogen and serum amyloid A). Except for some differences in clearance rates, no marked effects were observed in mice exposed to any spore at 10⁶ or 10⁷ colony forming units (cfu). In contrast, live Bc or Bt VCs (10⁵ or 10⁶?cfu) produced shock-like symptoms (lethargy, hunched appearance, ruffled fur, and respiratory distress), and 11–200-fold elevations in pyrogenic cytokines at 2-h post-exposure. In the study, 4-h effects included increased lethargy, ocular discharge, and 1.5–4-fold rise in circulatory acute phase markers, but no indications of recovery. Bs VC did not produce any changes in symptoms or biomarkers. After 2 or 4?h of exposure to dead VC, increases of only plasma IL-1β and TNF-α (4.6- and 12.4-fold, respectively) were observed. These findings demonstrate that purified spores produced no marked effects in mice compared to that of metabolically active bacteria. This early screening regime was successful in distinguishing the pathogenicity of the different Bacillus species, and might be useful for assessing the relative hazard potential of other biotechnology-related candidate strains.