Exposure to metals premixed with microplastics increases toxicity through bioconcentration and impairs antioxidant defense and cholinergic response in a marine mysid

Coexistence of metals and microplastics (MPs) in aquatic environments represents a growing concern; however, little is known regarding the risks associated with their combined effects. Here, the effects of five metals (As, Cd, Cu, Pb, and Zn), alone or combined with MPs for various premixing durations (30 and 60 days), on the juvenile and adult stages of the marine mysid Neomysis awatschensis were evaluated. The toxicity (50% lethal concentration for 96 h) and bioconcentration of metals premixed with MPs were measured, and their effects on the antioxidant defense and cholinergic systems were examined. Metal toxicity increased with increasing premixing period with MPs, and juveniles were more sensitive to exposure to metals premixed with MPs than adults. Metal bioconcentration in the mysid body increased following co-exposure with MPs. Metals premixed with MPs significantly increased intracellular malondialdehyde content at both stages but decreased glutathione content in juveniles. At both stages, catalase and superoxide dismutase activity was suppressed following co-exposure to metals and MPs, except under the Cu treatment. Moreover, co-exposure inhibited acetylcholinesterase activity at both stages, suggesting cholinergic impairment. Taken together, metals and MPs produce synergistic detrimental effects on marine mysids in a stage-specific manner. Further studies are warranted to elucidate the role of MPs as a vector for contaminants and stimulator of toxicity in aquatic organisms.

In situ activation of therapeutics through bioorthogonal catalysis

Bioorthogonal chemistry refers to any chemical reactions that can occur inside of living systems without interfering with native biochemical processes, which has become a promising strategy for modulating biological processes. The development of synthetic metal-based catalysts to perform bioorthogonal reactions has significantly expanded the toolkit of bioorthogonal chemistry for medicinal chemistry and synthetic biology. A wide range of homogeneous and heterogeneous transition metal catalysts (TMCs) have been reported, mediating different transformations such as cycloaddition reactions, as well as bond forming and cleaving reactions. However, the direct application of 'naked' TMCs in complex biological media poses numerous challenges, including poor water solubility, toxicity and catalyst deactivation. Incorporating TMCs into nanomaterials to create bioorthogonal nanocatalysts can solubilize and stabilize catalyst molecules, with the decoration of the nanocatalysts used to provide spatiotemporal control of catalysis. This review presents an overview of the advances in the creation of bioorthogonal nanocatalysts, highlighting different choice of nano-scaffolds, and the therapeutic and diagnostic applications.

A single luminescence center ultra-broadband near-infrared LiScGeO4:Cr phosphor for biological tissue penetration

In this work, in order to meet the application of near-infrared phosphor-converted light emitting diodes (pc-LEDs), an ultra-broadband emission phosphor, LiScGeO4:Cr, was synthesized. Its FWHM reaches 335 nm, and its emission spectrum ranges from 800 nm to 1650 nm, which almost covers the entire near-infrared second window (NIR-II). The broadband emission is thought to be caused by the 4T2 → 4A2 transition of the Cr3+ ion. This transition occurs due to the olivine structure of the crystal, which causes the Cr3+ ions to inhabit a low-symmetric crystal field, and the crystal field strength is very weak. NIR pc-LEDs were fabricated by combining a 460 nm blue LED with this phosphor, which penetrates 4 cm thick beef. The results indicate that there may be a potential application for this phosphor in the field of biological tissue penetration and non-destructive testing.

Synthesis of multimodal polymersomes for targeted drug delivery and MR/fluorescence imaging in metastatic breast cancer model

The objective of the current study is to design and delivery of targeted PEG-PCL nanopolymersomes encapsulated with Gadolinium based Quantum Dots (QDs) and Doxorubicin (DOX) as magnetic resonance-florescence imaging and anti-cancer agent. Diagnostic and therapeutic efficiency of the prepared theranostic formulation was evaluated in vitro and in vivo. Hydrophobic QDs based on indium-copper-gadolinium-zinc sulfide were synthesized and characterized extensively. Hydrophobic QDs and hydrophilic DOX were loaded in PEG-PCL polymersomes through double emulsion method. Drug release pattern was studied in both citrate (pH 5.4) and phosphate (pH 7.4) buffer during 10 days. Both fluorescence and magnetic properties of bare QDs and prepared formulations were studied entirely. AS1411 DNA aptamer was covalently attached to the surface of polymersomal formulation in order to prepare targeted drug delivery system. Cellular cytotoxicity and cellular uptake analysis were performed in both nucleolin positive (MCF7 and 4T1) and nucleolin negative (CHO) cell lines. After in vitro evaluations, anti-tumor efficiency and diagnostic capability of the formulation was investigated in 4T1 tumor baring mice. Scanning emission electron microscopy (SEM) confirmed spherical shape and around 100 nm size of prepared formulations. Transmission electron microscopy (HRTEM) showed crystal shape of QDs with size of 2-3 nm. Drug release study obtained controlled release of encapsulated DOX and stability of formulation in physiologic condition. MTT and flow cytometry results demonstrated that AS1411 aptamer could enhance both toxicity and cellular uptake in nucleolin overexpressing cell lines (P < 0.05). Moreover, aptamer targeted formulation could increase survival rate and tumor inhibitory growth effect in 4T1 tumor baring mice (P < 0.05). Our results verify that aptamer targeted polymersomes loaded with non-toxic QDs as a diagnostic agent and DOX as an anti-cancer drug, could provide a theranostic platform with the purpose of optimization of treatment process and minimization of systemic side effects.

Injectable and Radiopaque Liquid Metal/Calcium Alginate Hydrogels for Endovascular Embolization and Tumor Embolotherapy

Improved endovascular embolization can contribute to assistant treatment for patients. However, many traditional embolic materials, such as metal microcoils or liquid embolic agents, are associated with limitations of coil migration or recanalization. Herein, as the first trial, an injectable and radiopaque liquid metal/calcium alginate (LM/CA) hydrogel is introduced and fabricated as a candidate for endovascular embolization and tumor embolotherapy through developing LM droplets as radiopaque units into biocompatible calcium alginate cross-linked network. The adoption of LM droplets makes hydrogels radiopaque under X-ray and CT scan, which significantly facilitates the tracking of material location during surgical vascular operation. In addition, in vitro and in vivo experiments prove that such smart hydrogel could convert from liquid to solid rapidly via cross-linking, showing pretty flexible and controllable functions. Benefiting from these properties, the hydrogel can be performed in blood vessels through injection via syringes and then served as an embolic material for endovascular embolization procedures. In vivo experiments demonstrate that such hydrogels can occlude arteries and block blood flow until they ultimately lead to ischemic necrosis of tumors and partial healthy tissues. Overall, the present LM/CA hydrogels are promising to be developed as new generation embolic materials for future tumor embolotherapy.

Micronutrient Intake And Perceived Barriers Among Anaemic Pregnant Women In Aceh, Indonesia

BACKGROUND

Estimating vitamin, mineral intakes related to anaemia and describing perception regard pregnancy diet, accessibility to foodstuff among first ANC visitor of anaemic pregnant women aged above 20 years in Province Aceh, Indonesia.

METHODS

A cross sectional mixmethod of quantitatively and focus group discussion (FGD) was conducted at two municipalities having more than 40% anaemic pregnancy. One hundred fifty-eight anaemic pregnant women were interviewed regarding socio-demographic and three days of 24-hours food recall, in addition to FGD at each municipality using FGD guidelines about nutritional anaemia. Food recall data was analysed using software NutriSurvey Indonesia, deficiency is defined as daily intake below 77% recommended dietary allowances (RDA) Indonesia. The FGD result was analysed by content analysis and clarified with representative quotes.

RESULTS

Prevalence of deficiencies intake were folate (98.7%), vitamin B6 (91.1%), vitamin B2 (90.5%), iron (89.2%), zinc (87.3%), vitamin E (84.8%), vitamin C (79.7%), vitamin A (74.1%), copper (67.1%) and vitamin B12 (30.4%). Anaemic pregnant women noticed to consume more amount of food during pregnancy, and preferred to access foodstuff at shop nearby the house.

CONCLUSIONS

Other than low iron intake, more than 90% anaemic pregnant women were also deficiency in folate, vitamin B6 and vitamin B2. Perceived of less acknowledgement about affordable cost micronutrient-rich food, high cost of quality-food, sufficient to varieties foodstuff at neighbourhood shop prevents them from making correct food choices subsequently barrier to the food access and intake.

Dietary Intake of Essential, Toxic, and Potentially Toxic Elements from Mussels (Mytilus spp.) in the Spanish Population: A Nutritional Assessment

The levels of forty-three elements were determined in fresh, preserved, and frozen mussels (n = 208) with the purpose of evaluating their contribution to the recommended dietary intake of essential elements and their potential risk to Spanish consumers’ health. We found relevant differences in the element content in relation to the mode of conservation of mussels as well as in relation to their geographical origin, brand, or mode of production. According to our estimates, mussels are important contributors to the intake of most essential elements, contributing almost 70% of daily requirements of Se, 30–35% of Mo, Zn, and Co, and around 15% of Fe. At the same time, the pattern of average consumption of mussels in Spain does not seem to imply an excessive risk associated with any of the 36 toxic elements studied. However, it should be noted that, in the high percentile of consumption the exposure to Cd and As may be high, in particular that associated with the consumption of fresh and/or frozen mussels. According to the results of this study, a moderate consumption of mussels can be recommended as a valuable and safe source of trace elements.

Oral bioaccessibility of metal(loid)s in dust materials from mining areas of northern Namibia

Ore mining and processing in semi-arid areas is responsible for the generation of metal(loid)-containing dust, which is easily transported by wind to the surrounding environment. To assess the human exposure to dust-derived metal(loid)s (As, Cd, Cu, Pb, Sb, Zn), as well as the potential risks related to incidental dust ingestion, we studied mine tailing dust (n = 8), slag dust (n = 5) and smelter dust (n = 4) from old mining and smelting sites in northern Namibia (Kombat, Berg Aukas, Tsumeb). In vitro bioaccessibility testing using extraction in simulated gastric fluid (SGF) was combined with determination of grain-size distributions, chemical and mineralogical characterizations and leaching tests conducted on original dust samples and separated PM₁₀ fractions. The bulk and bioaccessible concentrations of the metal(loid)s were ranked as follows: mine tailing dusts < slag dusts ≪ smelter dusts. Extremely high As and Pb bioaccessibilities in the smelter dusts were caused by the presence of highly soluble phases such as arsenolite (As₂O₃) and various metal-arsenates unstable under the acidic conditions of SGF. The exposure estimates calculated for an adult person of 70 kg at a dust ingestion rate of 50 mg/day indicated that As, Pb (and also Cd to a lesser extent) grossly exceeded tolerable daily intake limits for these contaminants in the case of slag and smelter dusts. The high risk for smelter dusts has been acknowledged, and the safety measures currently adopted by the smelter operator in Tsumeb are necessary to reduce the staff's exposure to contaminated dust. The exposure risk for the local population is only important at the unfenced disposal sites at Berg Aukas, where the PM₁₀ exhibited high levels of bioaccessible Pb.

Nano-engineered delivery systems for cancer imaging and therapy: Recent advances, future direction and patent evaluation

Cancer is the second highest cause of death worldwide. Several therapeutic approaches, such as conventional chemotherapy, antibodies and small molecule inhibitors and nanotherapeutics have been employed in battling cancer. Amongst them, nanotheranostics is an example of successful personalized medicine bearing dual role of early diagnosis and therapy to cancer patients. In this review, we have focused on various types of theranostic polymer and metal nanoparticles for their role in cancer therapy and imaging concerning their limitation, future application such as dendritic cell cancer vaccination, gene delivery, T-cell activation and immune modulation. Also, some of the recorded patent applications and clinical trials have been illustrated. The impact of the biological microenvironment on the biodistribution and accumulation of nanoparticles have been discussed.

Preliminary clinical application of integrated 125I seeds stents in the therapy of malignant lower biliary tract obstruction

PURPOSE

To evaluate the clinical efficacy of percutaneous trans-hepatic integrated 125I seed stents implantation for malignant lower biliary tract obstruction.

METHODS

Thirty-two patients with malignant lower biliary obstruction were randomly divided into two groups. One group underwent the therapy with integrated 125I seed stents (Test group, n = 13), and another group received conventional metal stents implantation for treatment (Control group, n = 19). The pre- and post-operative changes in biochemical indices, white blood cell count, IgG level, stent patency, survival time, tumor size and complications were compared between the two groups. RECIST 1.1 (Response Evaluation Criteria In Solid Tumors) was used to evaluate therapeutic effects. The average follow-up time was 12.3 months.

RESULTS

The differences between pre- and post-operative (30 days) intragroup biochemical indices had statistically significant difference (P < 0.05), but there were no significant differences (P > 0.05) in leukocyte counts and IgG levels. As to the median time of stent patency and patients' survival, there were significant differences (P < 0.05) between Control and Test groups (3.9 months vs. 8.1 months, 139 days vs. 298 days, respectively). Three months after the operation, the average tumor size was reduced in the Test group, but was increased in the Control group (P < 0.05). There was no significant difference in the incidence of complications between the two groups. The evaluation results using RECIST 1.1 showed that there were statistically significant differences between the two groups in terms of the rates of remission, control, and progression (χ2 = 17.5, P < 0.05).

CONCLUSIONS

The study indicates that integrated 125I seed stents are effective in reducing jaundice symptoms, inhibiting tumor growth, improving stent patency and prolonging patient survival, which may serve as a safer and more feasible method in treating malignant lower biliary obstruction with minimal invasiveness.

Characterization and risk of exposure to elements from artisanal gold mining operations in the Bolivian Andes

Artisanal and small-scale gold mining (ASGM) offers low-skilled workers an opportunity to elevate themselves out of poverty. However, this industry operates with little to no pollution controls and the cost to the environment and human health can be large. The objectives of this study were to measure levels of arsenic (As), manganese (Mn), cobalt (Co), lead (Pb), and mercury (Hg) in the environment and characterize health risks to miners and residents in an area with active ASGM operations. An exposure assessment was conducted at two different mining sites and a nearby village in the Bolivian Anders. The resulting measurements were then used to quantify cancerous and noncancerous health risks to children and adults working at and living near ASGM areas. Soil concentrations of As were well above background levels and showed great variations between the village and mining area. Mercury vapor levels at the two mining sites were approximately 30 times larger than the EPA reference concentration. The risk of developing non-cancerous health effects were primarily due to exposure to As and Hg. The probability of individuals developing cancer was considerably increased with adult miners having a probability of 1.3 out of 100. Cancer potential was driven by exposure to As, with de minimus cancer risk from all other elements. Based on the environmental characterization of elements in soils and Hg vapors, the risk of developing cancerous and non-cancerous health outcomes were above a level of concern based on EPA risk assessment guidance. Personal protective equipment was not worn by workers and Hg amalgam is commonly heated in workers' homes. Better education of the risks of ASGM is needed as well as simple controls to reduce exposure.

Design of antibody-functionalized carbon nanotubes filled with radioactivable metals towards a targeted anticancer therapy

In the present work we have devised the synthesis of a novel promising carbon nanotube carrier for the targeted delivery of radioactivity, through a combination of endohedral and exohedral functionalization. Steam-purified single-walled carbon nanotubes (SWCNTs) have been initially filled with radioactive analogues (i.e. metal halides) and sealed by high temperature treatment, affording closed-ended CNTs with the filling material confined in the inner cavity. The external functionalization of these filled CNTs was then achieved by nitrene cycloaddition and followed by the derivatization with a monoclonal antibody (Cetuximab) targeting the epidermal growth factor receptor (EGFR), overexpressed by several cancer cells. The targeting efficiency of the so-obtained conjugate was evaluated by immunostaining with a secondary antibody and by incubation of the CNTs with EGFR positive cells (U87-EGFR+), followed by flow cytometry, confocal microscopy or elemental analyses. We demonstrated that our filled and functionalized CNTs can internalize more efficiently in EGFR positive cancer cells.

Intake of Vitamin and Mineral Supplements and Longitudinal Association with HbA1c Levels in the General Non-Diabetic Population--Results from the MONICA/KORA S3/F3 Study

Background

Lower levels of hemoglobin A_1c (HbA_1c) are associated with a decreased risk of cardiovascular complications in diabetic and non-diabetic individuals. The aim of the study was to longitudinally investigate the association between the use of 11 vitamins and minerals (vitamins E, C, D, B₁, folic acid, carotenoids, calcium, magnesium, zinc, iron, and selenium) and change in HbA_1c levels over 10 years in non-diabetic individuals drawn from the general population.

Methods

Baseline data were available from 4447 subjects included in the population-based “Monitoring of Trends and Determinants in Cardiovascular Diseases” (MONICA) Augsburg S3 survey (1994/95). Follow-up data were derived from 2774 participants in the follow-up survey named “Cooperative Health Research in the Region of Augsburg” (KORA) F3 (2004/05). Vitamin/mineral intake from supplements and medications was assessed in a personal interview, where participants were asked to bring product packages of preparations that had been ingested during the last 7 days prior to the examination. Associations between regular vitamin/mineral intake amounts and HbA_1c levels measured at baseline and follow-up were investigated using generalized estimating equation models. For carotenoids, analyses were stratified by smoking status.

Results

None of the investigated nutrients except for carotenoids was significantly associated with changes in HbA_1c levels after 10 years. Regular intake of carotenoids from supplements and medications in amounts > 6.8mg/d (upper tertile) was associated with an absolute –0.26% (95% CI: –0.43 to –0.08) lower increase in HbA_1c levels compared with no intake of carotenoids. An inverse association was observed in those who never smoked but not in (former) smokers.

Conclusion

Larger prospective and intervention studies in non-diabetic/non-smoking individuals are needed to confirm the results and to assess whether the observed associations between carotenoid intake and change in HbA_1c levels are causal. If our results are confirmed, high carotenoid intake could be one strategy for the prevention of cardiovascular complications in non-diabetic people.

Decolorization of Reactive Black-5 by Shewanella sp. in the Presence of Metal Ions and Salts

In this study, effect of various metal ions and salts on biodecolorization of Reactive black-5, azoreductase activity, and growth of Shewanella sp. strain IFN4 was evaluated. Among the tested metals, Cr²⁺, Pb(²⁺, Ni²⁺, Fe²⁺, and Mn²⁺ did not inhibit the biodecolorization of reactive black-5, azoreductase activity and bacterial growth. Three metals (Cu²⁺, Zn²⁺, and Co²⁺) delayed the decolorization process without completely inhibiting the reaction and also suppressed the bacterial growth. However, no dye decolorization was observed in the presence of Cd²⁺ (10 mg L⁻¹). Furthermore, bacterium decolorized the dye at high concentration (15 mg L⁻¹) of mixed metal ions. Strain IFN4 was also able to decolorize the dye at 50 g NaCl L⁻¹ and 60 g Na₂SO₄ L⁻¹. NaCl was found to be more inhibitory to bacterial growth than Na₂SO₄and the reverse was observed for azoreductase activity. These findings suggest that strain IFN4 could be used in designing a bioreactor for the treatment of textile effluent.

Partitioning of Dietary Metal Intake--A Metal Dietary Exposure Screening Tool

Detection of heavy metals at trace or higher levels in foods and food ingredients is not unexpected given the widespread unavoidable presence of several metals in nature, coupled with advancement in analytical methods and lowering limits of detection. To assist risk managers with a rapid risk assessment when facing these situations, a metal dietary exposure screening tool (MDEST) was developed. The tool uses food intake rates based on the National Health and Nutrition Examination Survey 2005-2010 consumption data for the U.S. population two+ years and up and for infants age six months to <two years based on the Nestlé Feeding Infants and Toddlers Study, and existing exposure limits for several frequently detected metals (e.g., inorganic arsenic, cadmium, chromium, lead, and mercury). The tool has data entry fields for detected concentrations and includes algorithms that combine metal levels with consumption data to generate screening-level exposure estimates, which it then compares to MDEST assigned default portions of the exposure limits in the risk characterization module. As a screening-level tool, the risk assessment output is intentionally conservative, public health protective, and useful for a rapid assessment to set aside issues that are not of concern. Issues that cannot be readily resolved using this screening tool will need to be further evaluated with more refined input data that are tailored to the specific question or situation under consideration.

Association between prenatal exposure to metals and neonatal morbidity

An association between prenatal exposure to (semi-)metals and of neonatal morbidity was assessed by introducing an oxidative stress as a possible intermediate step. An oxidative stress was measured by cell proliferation (CP) ratio in umbilical cord blood cells. Urine samples of 18 out of 58 enrolled women (31%) were positive for (semi-)metals; 25.9% of women were positive for aluminum (Al). The CP ratio was higher (1) in subjects with Al, (2) in mothers to newborns diagnosed as small-for-gestational age (p value = .052), (3) neonates that weighed less (p value = .079), and (4) in women who experienced repeated abortions (p value = .049). Our findings suggest the possibility of metal-induced oxidative stress.

Concentrations and potential health risks of metals in lip products

BACKGROUND

Metal content in lip products has been an issue of concern.

OBJECTIVES

We measured lead and eight other metals in a convenience sample of 32 lip products used by young Asian women in Oakland, California, and assessed potential health risks related to estimated intakes of these metals.

METHODS

We analyzed lip products by inductively coupled plasma optical emission spectrometry and used previous estimates of lip product usage rates to determine daily oral intakes. We derived acceptable daily intakes (ADIs) based on information used to determine public health goals for exposure, and compared ADIs with estimated intakes to assess potential risks.

RESULTS

Most of the tested lip products contained high concentrations of titanium and aluminum. All examined products had detectable manganese. Lead was detected in 24 products (75%), with an average concentration of 0.36 ± 0.39 ppm, including one sample with 1.32 ppm. When used at the estimated average daily rate, estimated intakes were > 20% of ADIs derived for aluminum, cadmium, chromium, and manganese. In addition, average daily use of 10 products tested would result in chromium intake exceeding our estimated ADI for chromium. For high rates of product use (above the 95th percentile), the percentages of samples with estimated metal intakes exceeding ADIs were 3% for aluminum, 68% for chromium, and 22% for manganese. Estimated intakes of lead were < 20% of ADIs for average and high use.

CONCLUSIONS

Cosmetics safety should be assessed not only by the presence of hazardous contents, but also by comparing estimated exposures with health-based standards. In addition to lead, metals such as aluminum, cadmium, chromium, and manganese require further investigation.

Bone formation controlled by biologically relevant inorganic ions: role and controlled delivery from phosphate-based glasses

The role of metal ions in the body and particularly in the formation, regulation and maintenance of bone is only just starting to be unravelled. The role of some ions, such as zinc, is more clearly understood due to its central importance in proteins. However, a whole spectrum of other ions is known to affect bone formation but the exact mechanism is unclear as the effects can be complex, multifactorial and also subtle. Furthermore, a significant number of studies utilise single doses in cell culture medium, whereas the continual, sustained release of an ion may initiate and mediate a completely different response. We have reviewed the role of the most significant ions that are known to play a role in bone formation, namely calcium, zinc, strontium, magnesium, boron, titanium and also phosphate anions as well as copper and its role in angiogenesis, an important process interlinked with osteogenesis. This review will also examine how delivery systems may offer an alternative way of providing sustained release of these ions which may effect and potentiate a more appropriate and rapid tissue response.

Dietary intake of metals by the population of Tarragona County (Catalonia, Spain): results from a duplicate diet study

The daily intakes of arsenic (As), beryllium, cadmium (Cd), cobalt, chromium, copper, mercury (Hg), manganese, nickel, lead (Pb), antimony, tin, thallium, uranium, vanadium, and zinc by an adult population living in Tarragona County (Catalonia, Spain) were determined by the duplicate diet method with a 10-day sampling period. Duplicate diet samples, prepared as per consumption, were collected during September 2010 in 20 restaurants offering a variety of daily menus (breakfast, lunch, and dinner). A total of 200 composite samples, corresponding to 600 individual samples, were prepared for trace elements analyses, which were carried out by inductively coupled plasma mass spectrometry. The results were compared with data from previous total diet studies (TDS) recently performed in the same geographical area. Notable differences in the intake of the toxic elements As, Cd, Hg, and Pb were found depending on the method used. It is concluded that both the duplicate diet method and the TDS may provide important and useful information to estimate human exposure to metals through the diet and their derived health risks. However, for comparison between surveys or for establishing temporal trends in the intake of metals, it seems to be recommendable to use always the same method. Notwithstanding, if the interest is only to know whether the intake of a certain element is below the tolerable intake, both methods are useful.

[Selection and spreading of antibiotic resistance in bacteria]

Use of an antibiotic may not only select for resistance against the agent itself, but may at the same time co-select for resistance against other antibiotics if resistance genes are linked on e.g. a plasmid. Resistance plasmids may also carry genes mediating resistance against metals and disinfectants. Therefore, abundant use of metals, e.g. copper and zinc for growth promotion in animals used for food, may also co-select for antibiotic resistance. The same applies to disinfectants, e.g. silver and chlorhexidine. Prudent use of antibiotics and these other agents is essential to control antibiotic resistance.

Dietary intake of metals and risk of Parkinson's disease: a case-control study in Japan

Metals are involved in several important functions in the nervous system. Zinc and iron are increased and copper is decreased in the substantia nigra in Parkinson's disease (PD). However, epidemiological evidence for the association of dietary intake of metals with the risk of PD is limited. We investigated the relationship between metal consumption and the risk of PD in Japan using data from a multicenter hospital-based case-control study. Included were 249 cases within 6 years of onset of PD based on the UK PD Society Brain Bank clinical diagnostic criteria. Controls were 368 inpatients and outpatients without a neurodegenerative disease. Information on dietary factors was collected using a self-administered diet history questionnaire. Higher intake of iron, magnesium, and zinc was independently associated with a reduced risk of PD: the adjusted OR in the highest quartile was 0.24 (95% CI: 0.10-0.57, P for trend=0.0003) for iron, 0.33 (95% CI: 0.13-0.81, P for trend=0.007) for magnesium and 0.50 (95% CI: 0.26-0.95, P for trend=0.055) for zinc. There were no relationships between the intake of copper or manganese and the risk of PD. Higher intake of iron, magnesium, and zinc may be protective against PD.

Metal sensitivity of the embryonic development of the ramshorn snail Marisa cornuarietis (Prosobranchia)

We investigated the effects of metal ions on the embryonic development of the ramshorn snail, Marisa cornuarietis, by exposing embryos to varying concentrations of copper (0, 50, 100, and 250 μg Cu(2+)/L), lead (0, 5, 10, and 15 mg Pb(2+)/L), lithium (0, 1, 2.5, and 3 mg Li(+)/L), or palladium (0, 50, 100, and 500 μg Pd(2+)/L). Effects of these metals were examined by recording mortality, the rate of tentacles and eyes formation, heart rate, hatching success, and weight after hatching. Compared to the control, we found a significant delay in the formation of tentacles and eyes after treatment with 100 μg Cu(2+)/L, 15 mg Pb(2+)/L, 2.5 mg Li(+)/L or 500 μg Pd(2+)/L. The heart rate decreased significantly at 500 μg Pd(2+)/L. At 10 mg Pb(2+)/L, 2.5 mg Li(+)/L, or 500 μg Pd(2+)/L, hatching was delayed significantly; 50 μg Cu(2+)/L induced a significantly earlier hatching, and reduced body weight. The LC(50) values were calculated to be about 50 μg Cu(2+)/L, 500 μg Pd(2+)/L, 2500 μg Li(+)/L, and 10000 μg Pb(2+)/L. These results show that the embryonic development of M. cornuarietis is about as sensitive to copper and lithium, compared to the most sensitive fishes used in embryo toxicity testing. Even though the MariETT is a laboratory-based assay focusing on toxicological endpoints of a selected model species, future application is envisaged to include testing of "natural" samples such as stream water or sediment interstitial water.

Molecular cloning, characterization and mRNA expression of selenium-dependent glutathione peroxidase from abalone Haliotis discus hannai Ino in response to dietary selenium, zinc and iron

A novel selenium-dependent glutathione peroxidase (Se-GPX) was cloned from abalone Haliotis discus hannai Ino (HdhGPx) by homology cloning with degenerate primers and RACE techniques. The full length of HdhGPx cDNA was 963bp with a 669bp open reading frame (ORF) encoding 222 amino acids and a 101bp eukaryotic selenocysteine insertion sequence (SECIS) in 3' untranslated region (UTR). It was showed that HdhGPx has a characteristic codon at (235)TGA(237) that corresponds to selenocysteine (SeC) as U(72). Sequence characterization revealed that HdhGPx contains a characteristic GPx signature motif 2 ((96)LGLPCNQF(103)), an active site motif ((179)WNFEKF(184)). In addition, two potential N-glycosylation sites ((112)NGTE(115) and (132)NLTQ(135)) were identified in HdhGPx. 3D modeling analysis showed that the overall structure of HdhGPx monomer had more similarity to human GPx3 than human GPx1. Relatively higher-level mRNA expression was detected in hepatopancreas, mantle and gonad by real-time PCR assays. The relative expression levels of HdhGPx mRNA in hepatopancreas and haemocytes were detected by real-time PCR in abalone fed with nine different diets containing graded levels of selenium (0.15, 1.32 and 48.7mgkg(-1)), zinc (6.69, 33.85 and 710.63mgkg(-1)) and iron (29.17, 65.7 and 1267.2mgkg(-1)) for 20weeks, respectively. The results showed that the expressions of HdhGPx mRNA were statistically higher at adequate dietary selenium (1.32mgkg(-1)), zinc (33.85mgkg(-1)) and iron (65.7mgkg(-1)) than those in low dietary minerals, respectively. But HdhGPx mRNA expression levels were down-regulated by high contents of dietary selenium (48.7mgkg(-1)), zinc (710.63mgkg(-1)) and iron (1267.2mgkg(-1)), respectively. These results indicated that adequate dietary minerals could increase the mRNA expression of HdhGPx, and then to increase the total antioxidant capacities in abalone.

Titanates deliver metal ions to human monocytes

Amorphous peroxotitantes (APT) are insoluble titanium-based particles that bind a variety of metal compounds with high affinity; these particles could be sequestered locally in a solid phase to deliver metal-based drugs. Previous studies have confirmed the 'biodelivery' of metals from metal-APT complexes to fibroblasts, but not monocytes. Our goal in the current study was to use monocytic cytokine secretion to assess delivery of gold or platinum-based compounds from APT to human THP1 monocytes. Cytokine secretion was not triggered by APT alone or metal-APT complexes. In monocytes activated by lipopolysaccharide (LPS), APT alone enhanced or suppressed IL1beta or IL6 secretion, yet TNFalpha secretion was unaffected. Complexes of APT and Au(III) or cis-platin altered LPS-activated IL6 or IL1beta secretion most, TNFalpha least. Our results suggest that the APT deliver metals to monocytes.

Dietary exposure to metals by individuals living near a hazardous waste incinerator in Catalonia, Spain: temporal trend

The concentrations of arsenic (As), beryllium (Be), cadmium (Cd), chromium (Cr), mercury (Hg), manganese (Mn), nickel (Ni), lead (Pb), tin (Sn), thallium (Tl), and vanadium (V) were determined in a number of foodstuffs purchased during 2006 in various localities of Tarragona County (Catalonia, Spain), near a hazardous waste incinerator, which has been operating since 1999. The dietary intake of the above elements by the population of the area was subsequently estimated. The results were compared with those obtained in previous surveys (baseline 1997 and 2002) performed in the same area. The levels of Be, Tl, and V were under their respective limits of detection in all samples. The estimated dietary intakes of the elements analyzed in the current survey by an adult man of 70 kg were the following: 351 microg/day for As, 4.6 microg/day for Cd, 57.5 microg/day for Cr, 7.1 microg/day for Hg, 2,229 microg/day for Mn, 78.0 microg/day for Ni, 39.9 microg/day for Pb, and 37.9 microg/day for Sn. On average, fish and seafood were the main contributor to the total dietary intake of As, Cd, and Hg and one of the most important for Pb. In general terms, the differences on metal exposure through dietary intake between the present and our two previous surveys were not particularly relevant. The current intake of the most toxic elements (As, Cd, Hg, and Pb) remains under the respective Provisional Tolerable Weekly Intakes established by the Food and Agriculture Organization/World Health Organization.

Dominance of dietary intake of metals in marine elasmobranch and teleost fish

Metal accumulation in marine fish is a global public health concern, because the consumption of seafood provides the largest dose of many toxic metals to humans. While water quality criteria often rely on aqueous exposures of metals to fish in developing safety guidelines, it is increasingly recognized that marine fish obtain an important fraction of their metal body burden from their diet. Using experimental data, we modeled the accumulation of six metals (Am, Cd, Cs, Co, Mn, Zn) from diet and from the aqueous phase in two marine fish species, the teleost Psetta maxima and elasmobranch Scyliorhinus canicula. We estimated steady-state metal concentrations and calculated the relative contributions of dietary and aqueous intake in both species. For both species >60% and often >90% of Mn, Cd, and Zn derives from dietary intake in these species, even at the lowest ingestion rates reported for these fish. At low ingestion rates, Am was obtained predominantly from the aqueous phase and Cs varied considerably depending on prey selection. Inter-specific differences were noted, especially in Co uptake. Model predictions of steady-state tissue metal concentrations are within the range of field measurements for these species. Our findings underscore the importance of including dietary exposure in understanding metal accumulation in marine fish.

Phenolics composition in Erica sp. differentially exposed to metal pollution in the Iberian Southwestern Pyritic Belt

The phenolic composition of different populations of Erica andevalensis,E. australis and E. arborea was analyzed according to the different degree of exposition to metals in soils. E. andevalensis populations, highly exposed to metal pollution, had the lowest total phenol content and the lowest antioxidant activity measured as trolox equivalents. The HPLC analysis of leaf extracts revealed that phenolic composition in all analyzed populations of E. australis and E. arborea was very similar, although wild populations were differentially exposed to metal pollutions. However, E. andevalensis showed a phenolic profile characterized by the absence of many phenolic compounds quantified in the other species, although two compounds derived from cinnamic and coumaric acids were exclusively observed in this species.

Estimating bioconcentration factors, lethal concentrations and critical body residues of metals in the mollusks Perna viridis and Mytilus edulis using ion characteristics

Quantitative structure-activity relationships (QSARs) for metal bioconcentration factors (BCF) and median acute lethal water concentrations (LC50) were developed for two species of mollusks, Perna viridis and Mytilus edulis. These endpoints were related to four metal ion characteristics, the covalent index (chi(2)(m)r) (r represents the ion radius in A), the softness index (sigma(p)), the hydrolysis constant (K(OH)) and the ionic index (Z(2)/r). The BCF and LC50 were significantly correlated to chi(m)(2)r. The coefficients of determination r(2) for the relationships with other metal descriptors were much lower. Critical body residue (CBR) QSARs were derived by multiplying the chi(2)(m)r-based BCF and LC50 regressions. The CBRs were independent of the covalent index chi(2)(m)r, as BCF and LC50 scaled to chi(2)(m)r with slope that had opposite signs. Comparison of the estimated CBRs with independent empirical values confirmed the predicted trends, but substantial deviations were noted too.

Changes in serum biochemical parameters of freshwater fish Oreochromis niloticus following prolonged metal (Ag, Cd, Cr, Cu, Zn) exposures

Fish serum may reflect status of many biochemical processes in the metabolism. Heavy metals, as environmental stressors, may alter serum biochemical parameters in fishes. Thus, freshwater fish, Oreochromis niloticus, were exposed to low levels (0.05 mg/L) of metals (silver [Ag], cadmium [Cd], copper [Cu], chromium [Cr], zinc [Zn]) to investigate responses of serum biochemical parameters over different exposure periods (0, 5, 10, 20, 30 d). Fish mortality occurred only in Ag exposure, as all fish died between days 12 to 16. Activities of alkaline phosphatase (ALP), alanine transaminase (ALT), and aspartate transaminase (AST) were altered only in Cu- and Cd-exposed fish. Both Cd and Cu exposures decreased the activity of ALP, although they increased the activities of ALT and AST. Glucose concentrations increased in Ag-, Cd-, and Cu-exposed fish, with a sharp increase occurring in Ag-exposed fish before mortality began. Total protein and triglyceride concentrations increased in Ag-exposed fish, although they decreased in Cu-exposed ones. However, all metal exposures increased cholesterol concentration in the serum. Concentration of blood urea nitrogen increased in Ag-, Cd-, and Cu-exposed fish, although it decreased in Cr-exposed ones. Calcium level decreased only in Cu-exposed fish, and Cl(-) level decreased in Ag-exposed fish. Silver and Cu exposures also decreased Na(+) level in the serum. Cadmium and Cu exposures increased serum K(+) levels. The present study, investigating the effects of environmentally realistic metal exposures on serum biochemical parameters, demonstrated that fish serum could sensitively reflect environmental metal stress. Thus, it suggests that serum biochemical parameters could be used as important and sensitive biomarkers in ecotoxicological studies concerning the effects of metal contamination and fish health.

Analysis of food for toxic elements

The levels of the toxic elements Al, As, Cd, Hg, Pb and Sn are routinely monitored in food to protect the consumer. Increasingly, the chemical forms of As and Hg are also monitored. Analyses are performed to enforce regulatory standards and to accumulate background levels for assessing long-term exposure. The analytical procedures used for these activities evolve as requirements to determine lower levels arise and as both the types and sheer number of different foods that need to be analyzed increase. This review highlights recent work addressing improvements in the analysis of toxic elements in food. The topics covered include contamination control, analytical sample treatment and the common analytical techniques used for food analysis.

Systemic translocation of particulate matter-associated metals following a single intratracheal instillation in rats

Respirable ambient particulate matter (PM) exposure has been associated with an increased risk of cardiovascular disease. Direct translocation of PM-associated metals from the lungs into systemic circulation may be partly responsible. We measured elemental content of lungs, plasma, heart, and liver of healthy male WKY rats (12-15 weeks old) 4 or 24 h following a single intratracheal (IT) instillation of saline or 8.33 mg/kg of oil combustion PM (HP-12) containing a variety of transition metals with differing water and acid solubility. Tissues were digested with a combination of quaternary acid, amine, and nitric acid and analyzed using inductively coupled plasma-atomic emission spectroscopy. Lung levels of metals were lower at 24 h than at 4 h. Metals with high water solubility and relatively high concentration in HP-12 were increased in extrapulmonary organs. Water-soluble nonessential metals, like vanadium and nickel, were increased in plasma, hearts, and livers of exposed animals at both time points. Exposure-related small increases in essential metals, like zinc and manganese, were also noted in extrapulmonary tissues at both time points. Lead, with low water solubility but high acid solubility, was detected in liver only at 24-h postinstillation. Elements with low water or acid solubility, like silicon and aluminum, were not detected in extrapulmonary tissues despite decreased levels in the lung suggesting mucociliary clearance. We have shown that HP-12-associated metals translocate to systemic circulation and extrapulmonary organs following IT exposure. This translocation is dependent upon their relative levels and water solubility. Thus, following inhalation, PM-associated metals deposited in the lung may be released into systemic circulation at different rates depending on their water/acid solubility, thereby providing a means by which metals may elicit direct extrapulmonary effects.

Hinokitiol, a metal chelator derived from natural plants, suppresses cell growth and disrupts androgen receptor signaling in prostate carcinoma cell lines

Hinokitiol (beta-thujaplicin), a troplone-related compound found in the heartwood of cupressaceous plants, strongly inhibits the proliferation of a broad range of tumor cell lines. This is the first report to demonstrate that hinokitiol, a metal chelator derived from natural plants, suppresses cell growth and disrupts AR signaling in prostate carcinoma cell lines. Our present studies indicate that hinokitiol suppresses androgen/AR-mediated cell growth and androgen-stimulated DNA synthesis by [(3)H]thymidine incorporation in a dose- and time-dependent manner. Hinokitiol simultaneously suppresses the intracellular and secreted PSA levels, a marker for the progression of prostate cancer. Hinokitiol significantly represses the AR mRNA and protein expression in a dose- and time-dependent manner. Additionally, the ligand-binding assay shows that hinokitiol blocks binding of the synthetic androgen [(3)H]R1881 to AR in LNCaP cells. These findings collectively suggest that hinokitiol is potentially effective against prostate cancer in vitro, and thus it might become a novel chemopreventive or chemotherapeutic agent for prostate cancer.

Metal chelates of 2-hydroxy-4-methylthiobutanoic acid in animal feeding. Part 2: Further characterizations, in vitro and in vivo investigations

The alpha-hydroxyacid 2-hydroxy-4-methylthiobutanoic acid (the so-called methionine hydroxy-analogue, MHA), largely used in animal nutrition as a source of methionine, forms stable metal chelates with divalent metals of formula [{CH(3)SCH(2) CH(2)CH(OH)COO}(2)M].nH(2)O. Protonation and iron(III) and copper(II) complex formation constants have been determined by potentiometry at 25 degrees C. Distribution diagrams show that no free Fe(3+) cations are present in solution at pH>2.5. ESI-MS (Electron-Spray Ionization Mass Spectrometry) investigations carried out both on iron and zinc complexes in solution have evidenced various species with different MHA/metal ratios. In vivo trials were carried out with rats. After receiving a zinc-deficient diet for 3 weeks, animals were fed the same diet added with zinc sulfate or zinc/MHA chelate; the zinc content of faeces was higher (+45%; P<0.05) in sulfate fed rats, whereas zinc retention was higher (+61%; P<0.05) in the Zn/MHA diet. Experiments in vitro with human intestinal Caco-2 cells indicated that the MHA/Fe chelate was taken up by the cells without any apparent toxic effect. The iron uptake was higher than that of iron nitrilotriacetate (Fe(3+)NTA), an effective chelate for delivering iron to milk diets. In conclusion, these data indicate that the use of MHA chelates could be a valuable tool to increase bioavailability of trace minerals and reduce the environmental impact of animal manure.

Reliability of a semi-quantitative method for dermal exposure assessment (DREAM)

Valid and reliable semi-quantitative dermal exposure assessment methods for epidemiological research and for occupational hygiene practice, applicable for different chemical agents, are practically nonexistent. The aim of this study was to assess the reliability of a recently developed semi-quantitative dermal exposure assessment method (DREAM) by (i) studying inter-observer agreement, (ii) assessing the effect of individual observers on dermal exposure estimates for different tasks, and (iii) comparing inter-observer agreement for ranking of body parts according to their exposure level. Four studies were performed in which a total of 29 observers (mainly occupational hygienists) were asked to fill in DREAM while performing side-by-side observations for different tasks, comprising dermal exposures to liquids, solids, and vapors. Intra-class correlation coefficients ranged from 0.68 to 0.87 for total dermal exposure estimates, indicating good to excellent inter-observer agreement. The effects of individual observers on task estimates were estimated using a linear mixed effect model with logged DREAM estimates as explanatory variable; "task", "company/department", and the interaction of "task" and "company/department" as fixed effects; and "observer" as a random effect. Geometric mean (GM) dermal exposure estimates for different tasks were estimated by taking the exponent of the predicted betas for the tasks. By taking the exponent of the predicted observer's intercept (exp(omega i)), a multiplier (M(O)) was estimated for each observer. The effects of individual observers on task estimates were relatively small, as the maximum predicted mean observers' multiplier was only a factor 2, while predicted GMs of dermal exposure estimates for tasks ranged from 0 to 1226, and none of the predicted individual observers' multipliers differed significantly from 1 (t-test alpha = 0.05). Inter-observer agreement for ranking of dermal exposure of nine body parts was moderate to good, as median values of Spearman correlation coefficients for pairs of observers ranged from 0.29 to 0.93. DREAM provides reproducible results for a broad range of tasks with dermal exposures to liquids, solids, as well as vapors. DREAM appears to offer a useful advance for estimations of dermal exposure both for epidemiological research and for occupational hygiene practice.

Coadministration of Gatifloxacin and Multivitamin Preparation Containing Minerals: Potential Treatment Failure in an Elderly Patient

OBJECTIVE:

To report a case of probable treatment failure in a patient receiving gatifloxacin and a multivitamin preparation containing minerals.

CASE SUMMARY:

A 77-year-old white woman was prescribed gatifloxacin for hospital-acquired bacterial pneumonia. She was also receiving calcium carbonate 500 mg twice daily and a multivitamin preparation containing minerals once a day. Three days after gatifloxacin was started, the patient was still febrile, coughing, and not responding clinically. It was noted that nurses were administering the gatifloxacin tablet at the same time as the multivitamin tablet. The time of administration for gatifloxacin was changed to 6 hours after the patient received her multivitamin preparation. Two days later, she clinically improved.

DISCUSSION:

Studies have shown that the bioavailability of gatifloxacin is decreased with concurrent administration of antacids containing aluminum or magnesium; dietary supplements containing zinc, magnesium, and iron; multivitamin preparations containing minerals; and sucralfate. An objective causality assessment revealed that the adverse drug effect was probable.

CONCLUSIONS:

This case illustrates the need to recognize this potential interaction and to know how to avoid possible treatment failure.

The accumulation of potentially-toxic metals by grazing ruminants

The main factors affecting the accumulation of potentially-toxic metals (PTM) by grazing animals are the presence of the metal, its concentration in herbage and at the soil surface, and the duration of exposure to the contaminated pasture and soil. In addition, the elapsed time between the contamination of the pasture and grazing, the quantity of soil ingested together with herbage, the mechanism of absorption of the metal into blood and the presence or absence of antagonistic metals can interact to influence the rate and extent of accumulation of heavy metals in edible body tissues. Models of the accumulation of metals by grazing animals may be used to determine the statutory limits of radionuclides and PTM in soils under grazed pastures. Meta-analysis of existing data, using a random-effects model, is a useful approach to understanding the factors affecting the accumulation of some metals, e.g. Cd. The target edible body tissues for the accumulation of most PTM are the liver and kidneys, with the exception of radiocaesium, which accumulates in muscle to a greater extent than in other tissues. The livers and kidneys of mature livestock that have been grazed on areas of pasture at the legal limit of contamination by Cd for more than one grazing season should be removed from the human food chain in order to reduce the risk of intake of Cd by the human population.

Dosimetry of metal tritide particles as evaluated by the ICRP 66 model and a biokinetic model from laboratory rats

Internal radiation from inhalation of metal tritide aerosols may present a significant radiation protection problem for nuclear facility workers. Dose was evaluated for three metal tritides: hafnium, titanium, and zirconium. The study included in vitro and in vivo exposures. The inhalation doses for the three materials were calculated by using the ICRP 66 lung model. The doses also were evaluated by a biokinetic model, which was developed according to the results of animal studies. Results showed that the hafnium tritide particles were the most dense but they had a lower dissolution rate and a higher retention rate. Among these three tritides, hafnium was classified as a Type S material according to the ICRP 66 publication, whereas titanium and zirconium ranked between Type M and F materials. The dissolution rate of hafnium tritide appeared to agree well with the in vitro and in vivo studies. The dissolution rates of the other two materials in the in vitro studies were a little higher than those of the in vivo studies. The doses calculated by the ICRP 66 model for all materials were approximately two orders smaller than the doses obtained by the animal studies. This bias was caused by the different intake methods of the ICRP 66 model (inhalation) and in the animal study (instillation). The doses were on the same order while correcting for deposition fractions. The effective doses for hafnium, titanium, and zirconium tritides were 5.43 x 10(-10), 9.05 x 10(-11), and 6.5 x 10(-10) Sv Bq(-1), respectively, according to the animal studies.

The Role of Antioxidant Micronutrients in the Prevention of Diabetic Complications

Diabetes mellitus is associated with an increased production of reactive oxygen species and a reduction in antioxidant defenses. This leads to oxidative stress, which is partly responsible for diabetic complications. Tight glycemic control is the most effective way of preventing or decreasing these complications. Nevertheless, antioxidant micronutrients can be proposed as adjunctive therapy in patients with diabetes. Indeed, some minerals and vitamins are able to indirectly participate in the reduction of oxidative stress in diabetic patients by improving glycemic control and/or are able to exert antioxidant activity. This article reviews the use of minerals (vanadium, chromium, magnesium, zinc, selenium, copper) and vitamins or cofactors (tocopherol [vitamin E], ascorbic acid [vitamin C], ubidecarenone [ubiquinone; coenzyme Q], nicotinamide, riboflavin, thioctic acid [lipoic acid], flavonoids) in diabetes, with a particular focus on the prevention of diabetic complications. Results show that dietary supplementation with micronutrients may be a complement to classical therapies for preventing and treating diabetic complications. Supplementation is expected to be more effective when a deficiency in these micronutrients exists. Nevertheless, many clinical studies have reported beneficial effects in individuals without deficiencies, although several of these studies were short term and had small sample sizes. However, a randomized, double-blind, placebo-controlled, multicenter trial showed that thioctic acid at an oral dosage of 800 mg/day for 4 months significantly improved cardiac autonomic neuropathy in type 2 diabetic patients. Above all, individuals with diabetes should be educated about the importance of consuming adequate amounts of vitamins and minerals from natural food sources, within the constraints of recommended sugar and carbohydrate intake.

Effects of Dietary Restriction and Metal Supplementation on the Accumulation of Iron-Laden Glial Inclusions in the Aging Rat Hippocampus

The mechanisms responsible for the pathological deposition of iron and other redox-active metals in the aging and degenerating mammalian CNS remain poorly understood. We previously demonstrated that normal aging and pharmacological (oxidative) stressors promote the transformation of astroglial mitochondria to iron-laden, diaminobenzidine (DAB)-positive cytoplasmic inclusions in sub-cortical regions of the rat brain. In the current study, we demonstrate that (1) numbers of DAB-positive glial granules in the rat dorsal hippocampus, an area implicated in learning and memory, progressively increase between 3, 12 and 22 months of age; (2) dietary restriction (40%), a manipulation that attenuates many mammalian aging processes, has no effect on the age-related accumulation of these gliosomes in the rat hippocampus; and (3) the latter can be accelerated by dietary supplementation of iron and copper. Our data support the view that dietary exposure to iron and/or copper in adult life can impact the sequestration of redox-active metals in aging hippocampal astroglia.

[Infections caused by piercing and tattoos--a review]

Piercing, i.e. perforation of skin or mucous membranes in order to attach mostly metallic jewelery as well as multicolored skin tattooing have become more popular than ever before and a considerable number of (young) people practise these methods of body art which are supposed to increase the individuality. But there is a lot of side effects, among them especially infections. The most important bacteria cultivated from such patients are Staphylococcus aureus, group A streptococci and Pseudomonas aeruginosa. Viruses which can be transmitted by piercing or tattooing are especially hepatitis B virus and hepatitis C virus. Besides local bacterial infections also systemic infections (sepsis, endocarditis) occur. The main aspects of diagnostics, therapy and prevention are discussed.

Boon and bane of metal ions in medicine

In biological systems metal ions promote responses that range from deficiency to toxicity. Some, such as iron and zinc, have a known optimal intake range for normal, healthy individuals. Metal ions contained within well-designed molecules already constitute a great boon for the medicinal pharmacopoeia. However, whether essential or not, the threshold for toxicity can be very low. One of the challenges of designing metal-based drugs is to balance the potential toxicity of an active formulation with the substantial positive impact of these increasingly common therapeutic and diagnostic aids.

Determination of several elements in duplicate meals from catering establishments using closed vessel microwave digestion with inductively coupled plasma mass spectrometry detection: estimation of daily dietary intake

An estimation of the dietary exposure of French consumers to 21 essential and non-essential mineral elements using duplicate meals (breakfast and lunch) purchased from catering establishments was investigated after digestion by a closed vessel microwave procedure and quantification by ICP-MS. Daily dietary exposure estimates for metals and minerals were compared with the Provisional Tolerable Weekly Intakes (PTWI), the Tolerable Daily Intake (TDI) or the Acceptable Daily Intakes (ADI), as established by the FAO/WHO to estimate the risk of toxicity, and the US Recommended Daily Allowances (US RDA) or the Estimate Safe & Adequate Daily Dietary Intakes (ESADDI). Moreover, comparisons were made with those from previous French studies as well as those from other countries. The estimated mean daily intakes were 11 microgram for lithium, 3.42 g for sodium, 192 mg for magnesium, 2.03 mg for aluminium, 3.64 g for potassium, 642 mg for calcium, 154 microgram for chromium, 12.3 mg for iron, 2.15 mg for manganese, 4 microgram for cobalt, 74 microgram for nickel, 925 microgram for copper, 10.2 mg for zinc, 147 microgram for arsenic, 66 microgram for selenium, 112 microgram for molybdenum, 3.6 microgram for cadmium, 2.32 mg for tin, 3 microgram for antimony, 9 microgram for mercury and 34 microgram for lead. For the non-essential (toxic) elements, aluminium, tin, antimony, cadmium, arsenic, mercury and lead, the daily intake estimates were far below tolerable limits; and similar or somewhat lower than their respective PTWI, ADI, TDI, ESADDI and US RDA for individual minerals and essential trace elements, with good agreement with other country studies. The performance of the multi-elemental ICP-MS technique was also evaluated.

Liver targeting of human interferon-beta with pullulan based on metal coordination

Although interferon (IFN)-beta is widely used for the elimination of hepatitis C virus in patients with chronic liver disease, its clinical efficacy is unsatisfactory. Targeting IFN-beta to the liver might enhance its efficacy without increasing its side effects. The objective of the present study was to target IFN-beta to the liver to enhance its biological activity and reduce its side effects. A chelating residue, diethylenetriaminepentaacetic acid (DTPA), was introduced to pullulan, a water-soluble polysaccharide with a high affinity to the liver (DTPA-pullulan) and natural human IFN-beta was coordinately conjugated with the DTPA-pullulan by mixing in an aqueous solution containing zinc ions (Zn(2+)). Intravenous injection of the IFN-beta-DTPA-pullulan conjugate with Zn(2+) coordination into mice enhanced induction of an antiviral enzyme, 2',5'-oligoadenylate synthetase (2-5AS), specifically in the liver to a significantly greater extent than free natural IFN-beta. The enhanced 2-5AS level in the liver depended on the molar mixing ratio of IFN-beta, DTPA residue of the DTPA-pullulan, and Zn(2+). Moreover, the duration of the liver 2-5AS induction by the IFN-beta-DTPA-pullulan conjugate was longer than that by free natural IFN-beta. Thus, human IFN-beta-DTPA-pullulan conjugate appears to be applicable for clinical use, which is promising for treatment of patients with chronic hepatitis C.

IgG and IgE antibody responses following exposure of Brown Norway rats to trimellitic anhydride: comparison of inhalation and topical exposure

A variety of chemicals can cause sensitisation of the respiratory tract and occupational asthma, including certain acid anhydrides, diisocyanates and reactive dyes. As yet, no well-validated methods are available for the toxicological evaluation of the respiratory sensitising potential of chemicals. One approach which has been explored recently is the evaluation of induced IgE responses or cytokine expression patterns in rats or mice following topical exposure to chemical. Thus, it has been demonstrated that topical exposure of rodents to respiratory sensitising chemicals, but not to contact allergens, causes a dose-dependent and time-related increase in the concentration of total IgE. Using the reference respiratory allergen trimellitic anhydride (TMA), we have considered here the influence of route of exposure on the nature of induced immune responses. Specific IgG and IgE antibody responses and changes in total serum concentration of IgE have been measured following exposure of Brown Norway (BN) starin rats to TMA by topical administration or by inhalation. Exposure to TMA by both routes resulted in the stimulation of specific IgG and IgE antibody, although responses were considerably more vigorous after dermal exposure. Topical treatment also provoked marked and sustained increases in total serum IgE levels, whereas exposure via the respiratory tract stimulated a more transient elevation of this immunoglobulin in a minority of animals which reached statistical significance only at the highest dose group. The lesser vigour of the immune response following inhalation exposure is likely to be related to the considerably lower total antigenic dose which is delivered by this route. Nevertheless, these results show that the nature of immune response with respect to antibody isotype profile provoked by topical administration of TMA is qualitatively comparable with that stimulated by inhalation exposure to the same chemical. For the purposes of hazard assessment and identification of potential chemical respiratory allergens as a function of induced changes in serum IgE concentration, however, the evidence is that topical administration of test material is the preferred route of exposure.

Metal fume fever: a case report and literature review

Metal fume fever is a relatively uncommon presentation to the emergency department. Resulting from inhalation of metal oxides, it presents as an acute, self-limiting, flu-like symptom complex often misdiagnosed as a viral illness. We report a case of a 26-year-old male presenting with metal fume fever 4 h after oxycutting galvanized steel. The literature is reviewed with respect to pathogenesis, the common presenting symptom complex, investigations and current accepted management of metal fume fever.

Effects of metal salts on the oral production of volatile sulfur-containing compounds (VSC)

BACKGROUND/AIM

Halitosis, mainly caused by bacteria located on the posterior dorsum of the tongue and in periodontal pockets, is due to formation of volatile sulfur compounds (VSC). The hypothesis to be tested was that the affinity of a metal for sulfur determines its anti-VSC activity.

METHOD

Clinical tests were carried out on 12 subjects who rinsed with cysteine to induce halitosis (baseline) before rinsing with 7.34 mM ZnCl2, SnF2 and CuCl2. Mouth air VSC analyses were repeated following cysteine rinses at 1 h, 2 h and 3 h using a gas chromatograph. In vitro experiments tested toxic metals Hg2+, Pb2+ and Cd2+. 10-microl aliquots of metal salts were added to 1-ml aliquots of human whole saliva from 30 subjects. Samples were incubated overnight at 37oC and saliva headspace was analyzed for VSC in a gas chromatograph.

CLINICAL RESULTS

Cu2+>Sn2+>Zn2+ (supports hypothesis). Zn2+ had significantly less anti-VSC effect compared with Cu2+ and Sn2+ at 1, 2 and 3 h. In vitro results indicated that Hg2+, Cu2+ and Cd2+ had close to 100% anti-VSC effect, and that Pb2+ was less effective and Cd2+ more effective than expected in inhibiting VSC.

CONCLUSIONS

Apart from Hg2+ and Cu2+, the metals had a significantly greater effect on H2S than on CH3SH. Cu2+ and Hg2+ have well-known antibacterial activity and may presumably also operate by this mechanism.

Analysis of dietary intake of selected metals in the NHEXAS-Maryland investigation

As part of a large pilot investigation of multimedia exposure to several classes of environmental contaminants, the National Human Exposure Assessment Survey (NHEXAS)-Maryland study, we collected 388 semiquantitative food checklists and duplicate diet solid food samples, analyzed for arsenic, cadmium, chromium, and lead concentrations, from 80 individuals in Maryland in 1995-1996 in a repeated measures design. Here we explore several methods to infer foods most strongly associated with concentrations of these metals observed in the duplicate diet in our data set. We employed two techniques in which logarithmically transformed metal concentrations in the duplicate diet were regressed on individual food item consumption using algorithms designed to identify the foods most associated with the observed duplicate diet concentrations. We also employed an alternative strategy in which foods to be used as independent variables in regression were selected using data collected in national food consumption and residue surveys, with regression procedures proceeding with the selected foods in a similar manner. The concordance of foods selected as major predictors among these three techniques is noteworthy and is discussed. Finally, the Dietary Exposure Potential Model (DEPM) was used with the Dietary Checklist data to predict duplicate diet concentrations within our sample. A comparison between the predicted values and those observed gave R(2) values of 0.180, 0.206, and 0.076 for As, Cd, and Pb, respectively (p < 0.0001 in all cases). We discuss the significance of these observations and the implications for dietary-exposure-based risk analysis and dietary intake epidemiology.

Effects of metal-based environmental pollutants on tunicate hemocytes

Tunicates are filter feeding marine invertebrates that are susceptible to environmental contamination by toxic metals and polyaromatic hydrocarbons. Recently, we have shown that tunicate immune reactions are profoundly affected by exposure to tributyltin (TBT) and copper, both of which are components of marine antifouling paints. This study tests the effects of those pollutants on the hemocytes of tunicates. Immunofluorescence labeling with an anti-hemocyte monoclonal antibody demonstrated that the antigenic structure of the circulating hemocyte population was substantially affected by TBT and copper. Antigen-positive hemocytes were also found to accumulate in the pharyngeal papillae of TBT-exposed tunicates. Histological analyses indicated that this cellular accumulation in pharyngeal papillae involved refractile vacuolated hemocytes. Refractile vacuolated cells from TBT-exposed tunicates also occurred at greater frequencies in the circulating hemolymph, and had altered morphologies, compared to cells from nontreated controls. These data confirm that exogenous metals can have profound effects on the hemocytes of tunicates.