Tcadmium: a Threat to Aquatic Environment

ENVIRONMENTAL

~dEnvironmental

~tCadmium: a threat to aquatic environment

~w2009-10-2

Pollution,a problem of global concern has arisen due to man's greed to over exploit Mother Nature leading to introduction of various intrinsic as well as extrinsic elements in the environment. Industrial wastes, agricultural run off, urban garbage and some natural events put an increasing load of chemicals in to our water bodies there by depleting its life sustaining qualities. Industrial effluents, insecticides, detergents and heavy metals entering into water bodies create many problems to aquatic life. In India almost no water stream is safer for fish now a day. Among all these pollutants, heavy metals, due to their potential for bio-accumulation and biomagnifications in different trophic levels of ecosystem create serious threat to biosphere. They enter into aquatic environment through various anthropogenic as well as natural agencies; accumulate there and cause damages to aquatic life. They also enter into human bodies through food chain or water intake and cause various physiological disorders.

Authors: Awasthi, N. K.; Lodhi, Harnam Singh; Verma, Ravi Shanker.

Full Source: Aquacult 2009, 10(1), 97-103 (India)

~dEnvironmental

~tFuture use of DDT to combat malaria: model results can predict exposure for humans and the environment

~w2009-10-2

The insecticide DDT has been used for agriculture and malaria vector combat in the past. It has been phased out in many countries due to concerns about its hazards for the environment and human health. However, the World Health Organization has recently announced that DDT will play an important role in future malaria combat programs, given that it is still very efficient, cheap, and has a low acute toxicity. We have used a global fate model to predict environmental concentrations for the next 50 years in the tropical, temperate, and arctic regions. Results suggest that concentrations in Arctic oceans will be influenced by emissions in the tropics, whereas Arctic soils mainly contain residues from past emissions. The steady-state concentrations in the Arctic are lower than concentrations in the 1970s by about a factor of 100. In the tropics, the decrease is stopped by the ongoing emissions: steady-state concentrations are only a factor of five lower than maximal concentrations from the 1970s. This suggests that future DDT emissions will threaten the Arctic significantly less than past emissions to temperate regions did. In the tropics, where also the benefits of DDT occur, a significant exposure persists.

Authors: Schenker, U.; Scheringer, M.; Hungerbuhler, K.

Full Source: Organohalogen Compounds [computer optical disk] 2007, 69, 187/1-187/4 (Switzerland).

MEDICAL

~dMedical

~tA Mechanistic Investigation into the Irreversible Protein Binding and Antigenicity of p-Phenylenediamine

~w2009-10-2

Exposure to the skin sensitiser p-phenylenediamine (PPD) is associated with allergic contact dermatitis; however, the ability of PPD to modify protein has not been fully investigated. The aims of this study were to characterise the reactions of PPD and the structurally related chemical 2,5-dimethyl-1,4-benzoquinonediamine with model nucleophiles, a synthetic peptide (DS3) containing each of the naturally occurring amino acids and His-tagged glutathione-Stransferase (GSTP), and to explore the effect of di-Me substitution on PPD-specific T-cell responses using lymphocytes from allergic patients. The reductive soft nucleophiles N-acetyl cysteine and glutathione prevented PPD self-conjugation reactions and Bandrowski's base formation, but no adducts were detected. N-Acetyl lysine, a hard nucleophile, did not alter the rate of PPD degradation or form PPD adducts. With PPD and 2,5-dimethyl-1,4-benzoquinonediamine, only cysteine was targeted in the DS3 peptide. PPD and 2,5-dimethyl-1,4-benzoquinonediamine were also found to selectively modify the reactive Cys 47 residue of GSTP, which has a pKa of 3.5-4.2 and therefore exists in a largely protonated form. Glutathione formed mixed disulfides with the DS3 peptide, reducing levels of PPD binding. Lymphocytes from PPD allergic patients proliferated in the presence of PPD but not with 2,5-dimethyl-1,4-benzoquinonediamine. These results reveal that PPD and 2,5-dimethyl-1,4-benzoquinonediamine bind selectively to specific cysteine residues in peptides and proteins. Lymphocytes from PPD allergic patients were capable of discriminating between the different haptenic structures, suggesting that the hapten, but not the peptide moiety associated with MHC, is an important determinant for T-cell recognition.

Authors: Jenkinson, Claire; Jenkins, Rosalind E.; Maggs, James L.; Kitteringham, Neil R.; Aleksic, Maja; Park, B. Kevin; Naisbitt, Dean J.

Full Source: Chemical Research in Toxicology 2009, 22(6), 1172-1180 (UK).

~dMedical

~tInvestigations of the posttranslational mechanism of arsenite-mediated downregulation of human cytochrome P4501A1 levels: the role of heme oxygenase-1

~w2009-10-2

Arsenite, an environmental co-contaminant of polycyclic aromatic hydrocarbons (PAHs), diminishes the PAH-mediated upregulation of human CYP1A1, the enzyme that bioactivates PAHs to carcinogenic metabolites. Mechanistically, while transcriptional downregulation contributes to these effects, a role for posttranslational regulation was implicated but not proven. We hypothesise that arsenite induces heme oxygenase-1 (HO-1), which catabolizes CYP1A1 heme or cellular heme pools, thereby downregulating CYP1A1. Arsenite (5 íM), in HepG2 cells, induced HO-1 mRNA 7.4-fold over the 48 hours observation period, and it upregulated HO-1 protein expression. Arsenite decreased the induction of CYP1A1 by a PAH, benzo[k]-fluoranthene (BKF), by 50%; and transfection of HepG2 cells with siRNA targeting the human HO-1 gene, reduced the arsenite downregulation of BKF-induced CYP1A1 from 54% to 27%, relative to untransfected cells. Reconstituted HO-1 did not significantly catabolize CYP1A1 heme in vitro. Together these findings demonstrate that a posttranslational mechanism involving decreases in the cellular heme pool by arsenite-induced HO-1 may contribute to arsenite-mediated downregulation of CYP1A1.

Authors: Bessette, Erin E.; Fasco, Michael J.; Pentecost, Brian T.; Reilly, Andrew; Kaminsky, Laurence S.

Full Source: Journal of Biochemical and Molecular Toxicology 2009, 23(3), 222-232 (USA).

~dMedical

~tNickel mobilises intracellular zinc to induce metallothionein in human airway epithelial cells

~w2009-10-2

The authors recently reported that the induction of metallothionein (MT) was critical in limiting Ni-induced lung injury in intact mice. Nonetheless, the mechanism by which Ni induces MT expression is unclear. The authors hypothesised that the ability of Ni to mobilise Zn may contribute to such regulation and, therefore, examined the mechanism for Ni-induced MT2A expression in human airway epithelial (BEAS-2B) cells.Ni induced MT2A transcript levels and protein expression by 4 hours. Ni also increased the activity of a metal response element (MRE) promoter luciferase reporter construct, suggesting that Ni induces MRE binding of the metal transcription factor (MTF-1). Exposure to Ni resulted in the nuclear translocation of MTF-1, and Ni failed to induce MT in mouse embryonic fibroblasts lacking MTF-1. As Zn is the only metal known to directly bind MTF-1, the authors then showed that Ni increased a labile pool of intracellular Zn in cells as revealed by fluorescence-activated cell sorter using the Zn-sensitive fluorophore, FluoZin-3. Ni-induced increases in MT2A mRNA and MRE-luciferase activity were sensitive to the Zn chelator, TPEN, supporting an important role for Zn in mediating the effect of Ni. Although neither the source of labile Zn nor the mechanism by which Ni liberates labile Zn wa apparent, it was noteworthy that Ni increased intracellular reactive oxygen species (ROS). Although both N-acetylcysteine (NAC) and ascorbic acid (AA) decreased Ni-induced increases in ROS, only NAC prevented Ni-induced increases in MT2A mRNA, suggesting a special role for interactions of Ni, thiols, and Zn release.

Authors: Nemec, Antonia A.; Leikauf, George D.; Pitt, Bruce R.; Wasserloos, Karla J.; Barchowsky, Aaron.

Full Source: American Journal of Respiratory Cell and Molecular Biology 2009, 41(1), 69-75 (USA).

~dMedical

~tNAD(P)H quinone oxidoreductase 1 is essential for ozone-induced oxidative stress in mice and humans

~w2009-10-2

One host susceptibility factor for ozone identified in epidemiology studies is NAD(P)H quinone oxidoreductase 1 (NQO1). The authors hypothesised that after ozone exposure, NQO1 is required to increase 8-isoprostane (also known as F2-isoprostane) production, a recognised marker of ozone-induced oxidative stress, and to enhance airway inflammation and hyperresponsiveness. In this report, the authors demonstrate that in contrast to wild-type mice, NQO1-null mice are resistant to ozone and have blunted responses, including decreased production of F2-isoprostane and keratinocyte chemokine, decreased airway inflammation, and diminished airway hyperresponsiveness.Importantly, these results in mice correlate with in vitro findings in humans. In primary human airway epithelial cells, inhibition of NQO1 by dicumarol blocks ozone-induced F2-isoprostane production and IL-8 gene expression. Together, these results demonstrate that NQO1 modulates cellular redox status and influences the biology and physiology effects of ozone.

Authors: Voynow, Judith A.; Fischer, Bernard M.; Zheng, Shuo; Potts, Erin N.; Grover, Amy R.; Jaiswal, Anil K.; Ghio, Andrew J.; Foster, W. Michael.

Full Source: American Journal of Respiratory Cell and Molecular Biology 2009, 41(1), 107-113 (USA).

~dMedical

~tCadmium concentrations in blood and seminal plasma: correlations with sperm number and motility in three male populations (infertility patients, artificial insemination donors, and unselected volunteers)

~w2009-10-2

To investigate a possible common environmental exposure that may partially explain the observed decrease in human semen quality, the authors correlated seminal plasma and blood cadmium levels with sperm concentrations and sperm motility. The authors studied 3 separate human populations: group 1, infertility patients; group 2, artificial insemination donors; and group 3, general population volunteers. Information about confounding factors was collected by questionnaire. Seminal plasma cadmium did not correlate with blood cadmium. Both blood and seminal plasma cadmium were significantly higher among infertility patients than the other subjects studied. The percentage of motile sperm and sperm concentration correlated inversely with seminal plasma cadmium among the infertility patients, but not in the other 2 groups. Age (among infertility patients) was the only possible confounder correlating with seminal plasma cadmium. To validate the human findings in an animal model, the authors chronically exposed adolescent male Wistar rats to low-moderate cadmium in drinking water. Though otherwise healthy, the rats exhibited decreases in epididymal sperm count and sperm motility associated with cadmium dose and time of exposure. The human and rat study results are consistent with the hypothesis that environmental cadmium exposures may contribute significantly to reduced human male sperm concentration and sperm motility.

Authors: Benoff, Susan; Hauser, Russ; Marmar, Joel L.; Hurley, Ian R.; Napolitano, Barbara; Centola, Grace M.

Full Source: Molecular Medicine (Manhasset, NY, United States) 2009, 15(7-8), 248-262 (USA).

OCCUPATIONAL

~dOccupational

~tRisk of liver cancer and exposure to organicsolvents and gasoline vapours among Finnish workers

~w2009-10-04

In this study, the authors investigated the association between exposure to various groups of solvents and gasoline vapoursand liver cancer in Finnish workers. A cohort of economically-active workers born between 1906 and 1945 was followed upfor the 1971-1995 period. Incident cases of primary liver cancer (n) 2474) were identified in a record link with the Finnish CancerRegistry. Occupations from the 1970 census were converted toexposure using a job-exposure matrix. Cumulative exposure wascalculated as the product of estimated prevalence and exposure level and durationusing Poisson regression to calculate relative risks (RR). Amongoccupations entailing organic solvent exposure, an increased incidence ofliver cancer was observed in male printers and in varnishers and lacquerers.Among men, risk increased in the highest aromatic hydrocarbonexposure category (RR 1.77, 95% confidence interval [CI] 1.30-2.40),aliphatic/alicyclic hydrocarbons (RR 1.47, 95% CI 0.99-2.18), chlorinatedhydrocarbons (RR 2.65, 95% CI 1.38-5.11), and other solvents (RR2.14, 95% CI 1.23-3.71). The authors observed that among women, there was increased risk for the othersolvents group, which included mainly alcohols, ketones, esters, and glycolethers (RR 2.73, 95% CI 1.21-6.16). The authors concluded that the findings from this study that showed an increased risk amongworkers exposed to chlorinated hydrocarbons was in line with earlierstudies on trichloroethylene. In addition, the results suggested a link betweenexposure to other types of solvents and a risk of liver cancer. Thepossibility that alcohol consumption contributed to the observed risks cannot betotally excluded.

Authors: Lindbohm,Marja-Liisa; Sallmen, Markku; Kyyroenen, Pentti; Kauppinen,Timo; Pukkala, Eero

Full Source: International Journal of Cancer 2009, 124(12), 2954-2959 (Eng)

~dOccupational

~tElevated Cancer Mortality in a German Cohortof Bitumen Workers: Extended Follow-Up Through 2004

~w2009-10-04

In this study, the authors undertook a mortalityfollow-up in a cohort of German asphalt workers. It covered an additional 6 years. Seven thousand, nine hundred and nineteen male workers were classified into four exposurecategories: (1) exposure to bitumen only, (2) to bitumen and coal tar,(3) neither to tar nor to bitumen, and (4) unknown exposure. Exposure-specific standardised mortality ratios (SMR) and associated 95% confidenceintervals (CI) based on age- and calendar period-specificnational mortality rates were calculated. In order to compare exposed and unexposedworkers, relative risks were estimated by Poisson regression. Bythe end of 2004, 835 workers had died. The SMR for lung cancer was1.77 (95% CI 1.46-2.16). Head and neck cancer showed an SMR of2.36 (95% CI 1.78-3.07). Bladder cancer mortality was elevatedthreefold. In addition, the authors observed significantly elevated cancer-related SMRs for all malignant tumours. Furthermore, elevated mortality rates ofnonmalignant causes such as alcoholism, liver cirrhosis, and unnaturalcauses of deaths including accidents were detected. Following stratificationby exposure group, cancer mortality was elevated amongbitumen-exposed and unexposed subjects. In the internal analysis, theassociation between lung cancer and bitumen exposure was weakened ascompared with the previous follow-up (relative risk [RR] ) 1.15; 95%CI 0.72-1.84). The authors concluded that the findings from the follow up demonstrate an excess of cancer inthis cohort of asphalt workers. However, the observed mortality patternswere not clear. Although exposure to bitumen cannot be ruled outas being responsible for results, a higher prevalence of alcohol

and tobacco consumption may partially explain the detected risk increases.Exposure assessment in future studies should account formultiple occupational agents and nonoccupational factors to rule outthat the observed differences in SMR are not due simply to random

variation.

Authors:Behrens, Thomas; Schill, Walter; Ahrens, Wolfgang

Full Source: Journal of Occupational and Environmental Hygiene 2009,

6(9001), 555-561 (English)

~dOccupational

~tOccupational Exposure to Benzene at the ExxonMobil

Refinery at Baton Rouge, Louisiana (1977-2005)

~w2009-10-04

Crude oil contains up to 3% benzene.Previous studies of refinery workers have demonstrated an association between high chronic exposure to appreciable concentrations of benzene andacute myelogenous leukaemia. To date, no extensive industrial hygieneexposure analyses for historical benzene exposure have been performed,and none have focused on the airborne concentrations in the workplaceat specific refineries or for specific tasks. In this study, theauthors evaluated the airborne concentrations of benzene and their variabilityover time at the ExxonMobil refinery in Baton Rouge between1977 and 2005. Refinery workers were categorised into 117 workergroups using company job descriptions. These 117 groups were furthercollapsed into 25 job categories based on similarity of measuredexposure results. Results of 5289 personal air samples showed that 3403 were considered nontask (g 180 min) personalsamples, and 830 were considered task-related (< 180 min) personalsamples; the remainder did not fit in either category. In general,nontask personal air samples indicated that exposures of the past 30years were generally below the occupational exposure limit of 1 ppm,but there was only a small, decreasing temporal trend in the concentrations.The job sampled most frequently during routine operations wasprocess technician and, as broken down by area, resulted in the followingmean benzene concentrations: analysers (mean ) 0.12 ppm), coker(mean ) 0.013 ppm), hydrofiner (mean ) 0.0054 ppm), lube blendingand storage (mean ) 0.010 ppm), waste treatment (mean ) 0.092ppm), and all other areas (mean ) 0.055 ppm). Task-based samplesindicated that the highest exposures resulted from the sampling tasks,specifically from those performed on process materials; in general,though, even these tasks had concentrations well below the STEL of 5 ppm.The most frequently sampled task was gauging (mean ) 0.12 ppm). In addition, task-related exposures were similar across job categories for agiven task, with a few exceptions. The authors concluded that the findings from this study provide a task-focusedanalysis for occupational exposure to benzene during refineryoperations, which can be insightful for understanding exposures atthis refinery and perhaps others operated since about 1975.

Authors:Panko, Julie M.; Gaffney, Shannon H.; Burns, Amanda M.; Unice, Ken M.; Kreider, Marisa L.; Booher, Lindsay E.; Gelatt, RichardH.; Marshall, J. Ralph; Paustenbach, Dennis J.

Full Source: Journal of Occupational and Environmental

Hygiene 2009, 6(9001), 517-529 (English)

~dOccupational

~tDetermination of urine fluoride content among590 staff members in an electrolytic aluminium factory

~w2009-10-04

This study determined the urine fluorine content of thestaff members in an electrolytic aluminium factory in order to enhancethe health surveillance for the staff members. Occupational physical examination was carried out among the whole staff of this factory, urinesamples of workers were collected and urine fluorine content wasdetected. The urine fluorine content of the workers in the electrolyticaluminium workshop was higher than that of the administrativelogistical personnel, and the u test showed that u ) 16.35, the difference was significant. The authors concluded that based on the findings, ventilation should beenhanced in the workshop in order to reduce air pollution and protectthe workers' health.

Authors: Cao, Yong; Feng, Lei; Zhao, Tingrong

Full Source: Zhiye YuJiankang 2008, 24(7), 625-626 (Chinese)

~dOccupational

~tInfluence of CO on the nervous activity functionof the armoured car soldiers

~w2009-10-04

The influence of CO on the nervous activity of the armoured car soldiers was analysed by detecting CO concentrations inside the cabin andtesting the nervous activity of the armoured car soldiers. Observationgroup and the control were set up, gas automonitor system was appliedto detect CO concentration inside the cabin, and nervous activitymeasuring meter was used to test the nervous activity of the armouredcar soldiers. With the increase of CO concentration in the cabin, the visualand audio accurate rates of the soldiers decreased and the correctreaction time was lengthened, meanwhile, errors increased in number memory and the light signal vision. The authors concluded that the results suggest that CO might lead toa series of changes in the nervous activity and the military ability ofthe armoured car soldiers.