Nickel, chromium and cobalt in consumer products: revisiting safe levels in the new millennium

Screening for skin-sensitizing allergens among patients with clinically suspected allergic contact dermatitis

Objectives:

To detect common skin-sensitizing agents among patients experiencing allergic contact dermatitis (ACD).

Methods:

This was a retrospective study of 152 patients with clinically suspected ACD who underwent patch testing in an allergy clinic at King Khalid University Hospital, Riyadh, Kingdom of Saudi Arabia between January 2012 and February 2015. Of these patients, only 74 (48%) patients reacted to one or more contact allergens. This group of patients included 58 (78.4%) women and 16 (21.6%) men (mean age: 37.8±13.8 years). Patch testing was performed using the thin-layer rapid-use epicutaneous patch test panels.

Results:

Nickel sulfate was the most common sensitizing agent, with 26 (35.1%) patients yielding a positive result; followed by p-phenylenediamine in 17 (22.9%), butyl-tetra-phenol formaldehyde in 12 (16.2%), gold sodium thiosulfate in 10 (13.5%), and thimerosal in 6 (8.1%) patients. Nickel reactivity was significantly higher among women (41.4%) than among men (12.5%) (p<0.0001). Similarly, gold reactivity among women (15.5%) was also higher than among men (6.2%) (p≤0.02).

Conclusion:

The high level of skin sensitization due to nickel, PPD, and gold in patients with ACD emphasizes the need for measures to decrease exposure to these sensitizing agents.

Potential Health Benefits and Metabolomics of Camel Milk by GC-MS and ICP-MS

None of the research reports reveals the metabolomics and elemental studies on camel milk. Recent studies showed that camel milk possesses anticancer and anti-inflammatory activity. Metabolomics and elemental studies were carried out in camel milk which showed us the pathways and composition that are responsible for the key biological role of camel milk. Camel milk was dissolved in methanol and chloroform fraction and then vortexed and centrifuged. Both the fractions were derivatized by N,O-bis-(trimethylsilyl)trifluoroacetamide (BSTFA) and TMCS after nitrogen purging and analyzed by GC-MS. Camel milk was also analyzed by ICP-MS after microwave digestion. We found that higher alkanes and fatty acids are present in the chloroform fraction and amino acids, sugars and fatty acid derivatives are present in aqueous fractions. All the heavy metals like As, Pb, Cd, Co, Cu, and Ni were in the safe limits in terms of maximum daily intake of these elements. Na, K, Mg, and Ca were also present in the safe limits in terms of maximum daily intake of these elements. These results suggested that the camel milk drinking is safe and there is no health hazard. The present data of GC-MS and ICP-MS correlate the activities related to camel milk.

Gaultheria trichophylla (Royle): a source of minerals and biologically active molecules, its antioxidant and anti-lipoxygenase activities

BACKGROUND

Gaultheria trichophylla (Royle) is used as food and for treating many ailments in folk medicine especially against inflammation. The purpose of this in vitro study was to evaluate the ability of extracts of G. trichophylla as anti-oxidant and anti-inflammatory agent and for its mineral contents.

METHODS

Powdered plant material (100 g) was extracted with 100 ml each of methanol, chloroform, and n-hexane using soxhlet extractor. Antioxidant activity of methanol extract was assessed by DPPH radical scavenging and FRAP assays. Determination of enzyme inhibition activity was determined using 5-LOX inhibitory activity. Total phenolic and flavonoids contents were measured by Folin-Chicalteu and colorimeteric methods respectively. Minerals and heavy metals contents were determined using Atomic absorption spectrophotometer. Qualitative HPLC analysis were performed using some standard phenolic compounds.

RESULTS

The highest phenolic (17.5 ± 2.5 mg GA equivalent/g) and flavonoids (41.3 ± 0.1 mg QE equivalent/g) concentrations were found in methanol extract, which also showed more scavenging activity of 1, 1-diphenyl-2-picrylhydrazyl and ferrous reducing power with IC50 = 81.2 ± 0.2 and IC50 = 11.2 ± 0.1 μg/ml, respectively. The methanol and chloroform extracts showed best inhibition of 5-lipoxygenase enzyme with 90.5 ± 0.7% and 66.9 ± 0.1% at 0.5 mg/ml, respectively. G. trichophylla extract was also evaluated for mineral contents (K, Na, Ca, Mg, Fe, and Cu), and for chemical profiling of heavy metals (Cr, Pb, Cd, Co, Zn, Ni and Hg).

CONCLUSION

Our current findings suggest that this plant is good source of minerals and concentration of all heavy metals were within permissible limits. The results revealed that this ignored plant has great pharmaceutical and nutraceutical potential.

Evaluation of human exposure to metals from some commonly used hair care products in Nigeria

The concentrations of nine metals, namely, cadmium (Cd), lead (Pb), chromium (Cr), copper (Cu), cobalt (Co), nickel (Ni), manganese (Mn), zinc (Zn), and iron (Fe), were determined in 26 brands of hair care products including hair relaxers, conditioners and shampoos. The study was aimed at providing information on the possible risks arising from heavy metals associated with the use of these products. The concentrations of the metals were determined by means of atomic absorption spectrophotometry after digestion of the samples with a mixture of acids. The concentrations of the respective metals in hair relaxers, shampoos and conditioners were found to be 0.8–2.5, 0.6–3.0, <LOQ-2.8 μg g⁻¹ Cd; 4.5–26.0, <LOQ-28.0, <LOQ-425 μg g⁻¹ Pb; <LOQ-0.6, <LOQ-3.4, <LOQ-4.2 μg g⁻¹ Cr; <LOQ-3.5, <LOQ-6.0, <LOQ-3.5 μg g⁻¹ Cu; <LOQ-7.0, <LOQ-7.0, 0.5–4.5 μg g⁻¹ Co; 1.0-5.5, <LOQ-10.5, 1.5–6.0 μg g⁻¹ Ni; <LOQ-9.0, 2.0–25.5, <LOQ-15 μg g⁻¹ Mn; 36.5–48.0, 35.5–1080 μg g⁻¹, 30.0–69.0 μg g⁻¹ Zn; and 84.5–123, 66.7–284, 57.6–153 μg g⁻¹ Fe respectively. The systemic exposure dosage (SED) values of the studied metals were below their respective provisional tolerable daily intakes (PTDI)/recommended daily intakes (RDI), while the margins of safety were greater than 100 which indicate that these products are safe to use.

Chromium (VI)-Induced Immunotoxicity and Intracellular Accumulation in Human Primary Dendritic Cells

Chromium compounds, besides being occupational carcinogens, can also induce allergic contact dermatitis (ACD) and other immunomodulatory effects. In this study we investigate cell viability, uptake and intracellular distribution of chromium in human primary dendritic cells (DCs), either immature (iDCs) or driven to differentiate by a specific maturation stimulus (LPS) (mature DCs, mDCs), when exposed for 48 h to concentrations of soluble radiolabelled Na251CrO4 ranging from 5 to 0.5 μM. The modulation of the expression of membrane markers (CD80, CD86, MHC class II) correlated with the immunological functions of DCs was also measured. After 48 h of exposure the mean IC50 values in 4 donors were 36 and 31 μM in iDCs and mDC respectively, as detected by propidium iodide incorporation. Cellular uptake of chromium was nearly linear with increasing doses. At 48 h post-exposure chromium was accumulated preferentially in the nuclear and cytosolic fractions (44.1 to 66% and 13.1 to 31% of total cellular chromium, respectively). Although a high inter-individual variability was observed, an increase in the expression of CD86 and, to a lower extent, CD80 and MHC class II membrane markers was found in mDCs of single donors. These results highlight the relevance of searching for the biodistribution of trace metals in primary cells of the immune system. Moreover, they suggest that DCs differentiation markers can help in measuring the immunotoxicity of metal

Concentrations and exposure risks of some metals in facial cosmetics in Nigeria

The concentrations of nine metals (Cd, Pb, Ni, Cr, Co, Cu, Fe, Mn and Zn) were determined in lip sticks, lip glosses, lip balms, eye pencils, eyeliners, eye shadows, blushes, mascaras and face powders. The study was aimed at providing information on the risk associated with human exposure to metals in these facial cosmetic products. The concentrations of metals in the samples were measured by atomic absorption spectrometry after digestion with a mixture of nitric acid, hydrochloric acid and hydrogen peroxide. The mean concentrations of metals in these facial cosmetics ranged from 3.1 to 8.4 μg g^-1 Cd, 12-240 μg g^-1 Pb, 9.1-44 μg g^-1 Cr, 18-288 μg g^-1 Ni, 1.6-80 μg g^-1 Cu, 7.9-17 μg g^-1 Co, 2.3-28 mg g^-1 Fe, 12-230 μg g^-1 Mn, and from 18 to 320 μg g^-1 Zn. The concentrations of Ni, Cr and Co were above the suggested safe limit of 1 μg g^-1 for skin protection, while Cd and Pb were above the Canadian specified limits. The systemic exposure dosage (SED) values for these metals obtained from the use of these facial cosmetic products were below their respective provisional tolerable daily intake (PTDI)/or recommended daily intake (RDI) values. The margin of safety values obtained were greater than 100 which indicated that the concentrations of the metals investigated in these facial cosmetics do not present considerable risk to the users except in the case of face powders.

Metal allergy in eyelid dermatitis and the evaluation of metal contents in eye shadows

BACKGROUND

Allergic contact dermatitis is a common diagnosis in eyelid dermatitis. Sensitization to metals is prevalent in eyelid dermatitis and colour cosmetic products are frequently suspected as the source of metal exposure.

OBJECTIVE

To investigate the contact allergens for eyelid dermatitis and to assess metal contents in eye shadow products.

METHODS

Data were collected in the department of dermatology of Ewha Womans University hospital from December 1998 to February 2014. A total of 983 patients were patch tested during the period and 67 patients had eyelid dermatitis among them. To examine metal elements in colour cosmetic products for eyes, randomly selected 10 eye shadows were analysed.

RESULTS

Frequent allergens were metals, thiomersal and phenylenediamine in patients with eyelid dermatitis. The sensitization rates of individual allergens were not significantly different between patients with eyelid dermatitis and without eyelid dermatitis. All 10 eye shadow products contained more than 5 ppm of at least one element, nickel, cobalt or chromium.

CONCLUSION

Metals were top-rank allergens in patients with eyelid dermatitis as in the remaining patients patch tested. The eye shadow products contained significant amount of nickel, cobalt or chromium to elicit allergic reactions.

Safety evaluation of traces of nickel and chrome in cosmetics: The case of Dead Sea mud

BACKGROUND

Metal impurities such as nickel and chrome are present in natural ingredients-containing cosmetic products. These traces are unavoidable due to the ubiquitous nature of these elements. Dead Sea mud is a popular natural ingredient of cosmetic products in which nickel and chrome residues are likely to occur.

OBJECTIVE

To analyze the potential systemic and local toxicity of Dead Sea mud taking into consideration Dead Sea muds' natural content of nickel and chrome.

METHODS

The following endpoints were evaluated: (Regulation No. 1223/20, 21/12/2009) systemic and (SCCS's Notes of Guidance) local toxicity of topical application of Dead Sea mud; health reports during the last five years of commercial marketing of Dead Sea mud.

RESULTS AND CONCLUSIONS

Following exposure to Dead Sea mud, MoS (margin of safety) calculations for nickel and chrome indicate no toxicological concern for systemic toxicity. Skin sensitization is also not to be expected by exposure of normal healthy skin to Dead Sea mud. Topical application, however, is not recommended for already nickel-or chrome-sensitized persons. As risk assessment of impurities present in cosmetics may be a difficult exercise, the case of Dead Sea mud is taken here as an example of a natural material that may contain traces of unavoidable metals.

Characterisation and cytotoxic screening of metal oxide nanoparticles putative of interest to oral healthcare formulations in non-keratinised human oral mucosa cells in vitro

Nanoparticles are increasingly being utilised in the innovation of consumer product formulations to improve their characteristics; however, established links between their properties, dose and cytotoxicity are not well defined. The purpose of this study was to screen four different nanomaterials of interest to oral care product development in the absence of stabilisers, alongside their respective bulk equivalents, within a non-keratinised oral epithelial cell model (H376). Particle morphology and size were characterised using scanning electron microscopy (SEM) and dynamic light scattering (DLS). The H376 model showed that zinc oxide (ZnO) was the most cytotoxic material at concentrations exceeding 0.031% w/v, as assessed using the lactate dehydrogenase (LDH) and dimethylthiazolyl-diphenyl-tetrazolium-bromide (MTT) assays. ZnO cytotoxicity does not appear to be dependent upon size of the particle; a result supported by SEM of cell-particle interactions. Differences in cytotoxicity were observed between the bulk and nanomaterial forms of hydroxyapatite and silica (SiO2); titanium dioxide (TiO2) was well tolerated in both forms at the doses tested. Overall, nano-size effects have some impact on the cytotoxicity of a material; however, these may not be as significant as chemical composition or surface properties. Our data highlights the complexities involved at the nano-scale, in both the characterisation of materials and in relation to cytotoxic properties exerted on oral epithelial cells.

Estimated daily intake and health risk of heavy metals by consumption of milk

Cd, Co, Pb, Cu and Ni were analysed in 480 milk samples by flame atomic absorption spectrophotometry. Mean concentrations were 0.001, 0.061, 0.014, 0.738 and 0.028 mg/kg, respectively. Mean concentration of Cd was very low, whereas Cu exceeded the maximum limits established by the Codex Alimentarius. In some areas, the Pb concentration exceeded the maximum limit as set by the Codex Alimentarius. The highest estimated daily intake (EDI) of Cu calculated for male infants (1-3 year) was 33.534 µg/kg bw/day, while the lowest EDI was recorded for Cd (0.004 µg/kg bw/day) in adult females above 16 years. The results suggested that Cu and Pb from milk in the investigated areas may pose a health risk to the consumers.

Chromium released from leather - I: exposure conditions that govern the release of chromium(III) and chromium(VI)

Background

Approximately 1–3% of the adult population in Europe is allergic to chromium (Cr). A new restriction in REACH (Registration, Evaluation, Authorization and Restriction of Chemicals) based on the ISO 17075 standard has recently been adopted in the EU to limit Cr(VI) in consumer and occupational leather products.

Objectives

The aim of this study was to critically assess key experimental parameters in this standard on the release of Cr(III) and Cr(VI) and their relevance for skin exposure.

Material and methods

Four differently tanned, unfinished, leather samples were systematically investigated for their release of Cr(III) and Cr(VI) in relation to surface area, key exposure parameters, temperature, ultraviolet irradiation, and time.

Results

Although the total release of Cr was largely unaffected by all investigated parameters, except exposure duration and temperature, the Cr oxidation state was highly dynamic, with reduced amounts of released Cr(VI) with time, owing to the simultaneous release of reducing agents from the leather. Significantly more Cr(III) than Cr(VI) was released from the Cr-tanned leather for all conditions tested, and it continued to be released in artificial sweat up to at least 1 week of exposure.

Conclusions

Several parameters were identified that influenced the outcome of the ISO 17075 test.

Assessment of heavy metals contamination in Mamut river sediments using sediment quality guidelines and geochemical indices

This paper describes the concentration of selected heavy metals (Co, Cu, Ni, Pb, and Zn) in the Mamut river sediments and evaluate the degree of contamination of the river polluted by a disused copper mine. Based on the analytical results, copper showed the highest concentration in most of the river samples. A comparison with Interim Canadian Sediment Quality Guidelines (ICSQG) and Germany Sediment Quality Guidelines (GSQG) indicated that the sediment samples in all the sampling stations, except Mamut river control site (M1), exceeded the limit established for Cu, Ni, and Pb. On the contrary, Zn concentrations were reported well below the guidelines limit (ICSQG and GSQG). Mineralogical analysis indicated that the Mamut river sediments were primarily composed of quartz and accessory minerals such as chalcopyrite, pyrite, edenite, kaolinite, mica, and muscovite, reflected by the geological character of the study area. Enrichment factor (EF) and geoaccumulation index (Igeo) were calculated to evaluate the heavy metal pollution in river sediments. Igeo values indicated that all the sites were strongly polluted with the studied metals in most sampling stations, specifically those located along the Mamut main stream. The enrichment factor with value greater than 1.5 suggested that the source of heavy metals was mainly derived from anthropogenic activity such as mining. The degree of metal changes (δfold) revealed that Cu concentration in the river sediments has increased as much as 20 to 38 folds since the preliminary investigation conducted in year 2004.

Latham J, G. Dunlop D, Oreffo RO. Bone and metal: an orthopaedic perspective on osseointegration of metals

The area of implant osseointegration is of major importance, given the predicted significant rise in the number of orthopaedic procedures and an increasingly ageing population. Osseointegration is a complex process involving a number of distinct mechanisms affected by the implant bulk properties and surface characteristics. Our understanding and ability to modify these mechanisms through alterations in implant design is continuously expanding. The following review considers the main aspects of material and surface alterations in metal implants, and the extent of their subsequent influence on osseointegration. Clinically, osseointegration results in asymptomatic stable durable fixation of orthopaedic implants. The complexity of achieving this outcome through incorporation and balance of contributory factors is highlighted through a clinical case report.

Consideration of criteria required for assignment of a (skin) sensitiser a substance of very high concern (SVHC) under the REACH regulation

The identification, characterisation, risk assessment and risk management of materials that cause allergic sensitisation is an important requirement for human health protection. It has been proposed that for some chemical and protein allergens, and in particular for those that cause sensitisation of the respiratory tract (associated with occupational asthma), it may be appropriate to regard them as Substances of Very High Concern (SVHC) under the provisions of REACH (Registration, Evaluation, Authorisation and restriction of CHemicals). We have argued previously that categorisation of sensitising agents as SVHC should be used only in exceptional circumstances. In the present article, the subject of SVHC is addressed from another perspective. Here the information that would be required to provide a compelling case for categorisation of a skin sensitising substance as a SVHC is considered. Three skin sensitising chemicals have been identified to serve as working examples. These are chromate, a potent contact allergen, and the skin sensitisers formaldehyde and isoeugenol. The key criterion influencing the decision regarding a skin sensitiser being categorised as SVHC is the extent to which impacts on the quality of life are reversible. Consequently, SVHC categorisation for skin sensitising chemicals should be used only in exceptional circumstances.

Contact dermatitis in the cleaning industry

PURPOSE OF REVIEW

The review summarizes recent findings on contact dermatitis in the cleaning industry.

RECENT FINDINGS

Contact dermatitis is still an important issue in cleaning. Recent studies identified cleaning work sites and tasks, as well as specific cleaning products, which incur a risk increase for occupational contact dermatitis in cleaning. Workers involved in cleaning outdoors prevalence ratio [PR 1.85, 95% confidence interval (CI) 1.16-2.96], cleaning common areas of residential buildings (PR 1.77, 95% CI 1.11-2.84), schools (PR 1.84, 95% CI 1.15-2.93) and cleaning building sites (PR 1.87, 95% CI 1.18-2.95) showed significantly higher rates of contact dermatitis. Relevant allergens in cleaning are rubber chemicals and disinfectants. Leading allergens are thiurams (11.6%, 95% CI 9.1-14.1) and formaldehyde (3.4%, 95% CI 2.0-4.7), but contact with metal allergens might also be important. The most likely allergen sources for sensitization against rubber chemicals are protective gloves. High sensitization rates for disinfectants might result from the fact that employees in cleaning often use single-use medical examination gloves while cleaning. These gloves are not resistant to chemicals, which may break through the gloves within a short period of time, depending on glove material and thickness. No differences in sensitization rates and sensitization profiles were seen in cleaners of younger (≤40 years) and older (>40 years) age.

SUMMARY

Prevalence of occupational contact dermatitis is still high in cleaning. Irritant contact dermatitis is prevailing, but allergic contact dermatitis is quite frequent, too. Up to now, prevention strategies in cleaning seem to be insufficient.

A critical role for thymic stromal lymphopoietin in nickel-induced allergy in mice

Ni is the most frequent cause of contact allergy induced by metals. However, the underlying mechanism of this induction is unknown. Our previous research demonstrates that activation of dendritic cells (DCs) through p38MAPK/MKK6 is required for Ni-induced allergy in mice. In the current study, we investigated the cellular and molecular mechanisms underlying Ni-induced allergy using a mouse model that involves injecting Ni into the ear, with or without Freund's incomplete or complete adjuvants. Nickel had greater potential to cause allergic reactions compared with palladium and gold. Among the proteins expressed at higher levels in mice with Ni-induced allergy, we focused on thymic stromal lymphopoietin (TSLP), which is produced in abundance by keratinocytes. We detected increased expression of the TSLP receptor (TSLPR) in DCs from cervical lymph nodes of mice with Ni-induced allergy, suggesting that DCs in ear tissues were activated through TSLPR signaling induced by keratinocyte-derived TSLP. Furthermore, delayed-type hypersensitivity reactions in mice with Ni-induced allergy were decreased significantly by injection of a Tslp-short interfering RNA along with atelocollagen in the ear skin. These results suggest that Ni allergy may be triggered by a TSLP/TSLPR-mediated interaction between epithelial and immune cells.

Investigation of heavy metals in frequently utilized medicinal plants collected from environmentally diverse locations of north western India

The increasing prevalence of environmental pollution, especially soil contamination with heavy metals has led to their uptake in the human food chains through plant parts. Accumulation and magnification of heavy metals in human tissues through consumption of herbal remedies can cause hazardous impacts on health. Therefore, chemical profiling of nine heavy metals (Mn, Cr, Pb, Fe, Cd, Co, Zn, Ni and Hg) was undertaken in stem and leaf samples of ten medicinal plants (Acacia nilotica, Bacopa monnieri, Commiphora wightii, Ficus religiosa, Glycyrrhiza glabra, Hemidesmus indicus, Salvadora oleoides, Terminalia bellirica, Terminalia chebula and Withania somnifera) collected from environmentally diverse regions of Haryana and Rajasthan states in North-Western India. Concentration of all heavy metals, except Cr, was within permissible limits in the tested stem and leaf samples. Leaf samples had consistently more Cr compared to respective stem samples with highest concentration in leaf samples of Bacopa monnieri (13.19 ± 0.0480 ppm) and stem samples of Withania somnifera (4.93 ± 0.0185 ppm) both collected from Bahadurgarh (heavy industrial area), Haryana. This amount was beyond the permissible limit of 2.0 ppm defined by WHO for raw herbal material. Other two most perilous metals Pb (2.64 ± 0.0260) and Cd (0.04 ± 0.0274) were also recorded in Bahadurgarh region, although below permissible limits. Concentration of Hg remained below detectable levels in all the leaf and stem samples tested. These results suggested that cultivation of medicinal plants and other dietary herbs should be curtailed near environmentally polluted especially industrial areas for avoidance of health hazards.

Metal concentrations in cosmetics commonly used in Nigeria

Trace amounts of potentially toxic metals can be either intentionally added to cosmetics or present as impurities in the raw materials. In the present study, the levels of lead, cadmium, nickel, chromium, and mercury have been assessed in 28 body creams and lotions, 10 powders, 3 soaps, 5 eye make-ups, and 4 lipsticks widely available on Nigerian markets. The increases over suggested or mandated levels of lead in these creams and lotions ranged from 6.1 to 45.9 and from 1.2 to 9.2 mg kg⁻¹ when compared with Cosmetic Ingredients Review Expert Panel 2007 and German safe maximum permissible limit of lead in cosmetics, respectively. About 61% of the body cosmetics, the lotions, and the creams contained detectable levels of nickel ranging from 1.1 to 6.4-9.2 mg kg⁻¹. Chromium and mercury were undetected in 100% of the cosmetic product. Taken together, lead and cadmium were high in creams and lotions. Most of the imported creams and creamy white coloured cosmetics contained higher levels of metal contaminants than the other colours. Regulatory Agencies in developing nations should take appropriate action for cosmetics that contain lead and cadmium beyond the reference limits.

Assessment of lead and cadmium levels in frequently used cosmetic products in Iran

This study aims to investigate the content of lead and cadmium in most frequently used brands of cosmetic products (lipstick and eye shadow) in Iran. Fifty samples of lipstick (5 colors in 7 brands) and eye shadow (3 colors in 5 brands) were selected taken from large cosmetic stores in Isfahan (Iran) and lead and cadmium of them were analyzed. The results showed that the concentration of lead and cadmium in the lipsticks was within the range of 0.08–5.2 µg/g and 4.08–60.20 µg/g, respectively. The eye shadow samples had a lead level of 0.85–6.90 µg/g and a cadmium level of 1.54–55.59 µg/g. The content range of the heavy metals in the eye shadows was higher than that of the lipsticks. There was significant difference between the average of the lead content in the different brands of the lipsticks and eye shadows. Thus, the continuous use of these cosmetics can increase the absorption of heavy metals, especially Cd and Pb, in the body when swallowing lipsticks or through dermal cosmetic absorption. The effects of heavy metals such as lead can be harmful, especially for pregnant women and children. Therefore, effort must be made to inform the users and the general public about the harmful consequences of cosmetics.

Plasma Anti-Glycan Antibody Profiles Associated with Nickel level in Urine

Nickel (Ni) compounds are widely used in industrial and commercial products including household and cooking utensils, jewelry, dental appliances and implants. Occupational exposure to nickel is associated with an increased risk for lung and nasal cancers, is the most common cause of contact dermatitis and has an extensive effect on the immune system. The purpose of this study was two-fold: (i) to evaluate immune response to the occupational exposure to nickel measured by the presence of anti-glycan antibodies (AGA) using a new biomarker-discovery platform based on printed glycan arrays (PGA), and (ii) to evaluate and compile a sequence of bioinformatics and statistical methods which are specifically relevant to PGA-derived information and to identification of putative "Ni toxicity signature". The PGAs are similar to DNA microarrays, but contain deposits of various carbohydrates (glycans) instead of spotted DNAs. The study uses data derived from a set of 89 plasma specimens and their corresponding demographic information. The study population includes three subgroups: subjects directly exposed to Nickel that work in a refinery, subjects environmentally exposed to Nickel that live in a city where the refinery is located and subjects that live in a remote location. The paper describes the following sequence of nine data processing and analysis steps: (1) Analysis of inter-array reproducibility based on benchmark sera; (2) Analysis of intra-array reproducibility; (3) Screening of data - rejecting glycans which result in low intra-class correlation coefficient (ICC), high coefficient of variation and low fluorescent intensity; (4) Analysis of inter-slide bias and choice of data normalization technique; (5) Determination of discriminatory subsamples based on multiple bootstrap tests; (6) Determination of the optimal signature size (cardinality of selected feature set) based on multiple cross-validation tests; (7) Identification of the top discriminatory glycans and their individual performance based on nonparametric univariate feature selection; (8) Determination of multivariate performance of combined glycans; (9) Establishing the statistical significance of multivariate performance of combined glycan signature. The above analysis steps have delivered the following results: inter-array reproducibility ρ=0.920 ± 0.030; intra-array reproducibility ρ=0.929 ± 0.025; 249 out of 380 glycans passed the screening at ICC>80%, glycans in selected signature have ICC ≥ 88.7%; optimal signature size (after quantile normalization)=3; individual significance for the signature glycans p=0.00015 to 0.00164, individual AUC values 0.870 to 0.815; observed combined performance for three glycans AUC=0.966, p=0.005, CI=[0.757, 0947]; specifity=94.4%, sensitivity=88.9%; predictive (cross-validated) AUC value 0.836.

Detection of toxic metals (lead and chromium) in talcum powder using laser induced breakdown spectroscopy

A laser induced breakdown spectroscopic (LIBS) system was developed using a 266 nm laser and a high-resolution spectrograph (Andor SR 500 i-A) to detect the trace levels of the highly toxic metals such as lead and chromium present in different brands of talcum powder available in the local market. The strongest atomic transition lines of lead (Pb) (405.7 nm) and chromium (Cr) (425.4 nm) were used as spectral markers to simultaneously detect lead and chromium. The LIBS system was calibrated for these two heavy metals, and the system was able to detect 15-20 parts per million (ppm) of lead and 20-30 ppm of chromium in the talcum powder sample. The limits of detection of the LIBS system were also estimated, and they are 1.96 and 1.72 ppm per million respectively for lead and chromium. This study is highly significant due to the use of cosmetic products that could affect the health of millions of people around the globe.

A new strategy for pressed powder eye shadow analysis: allergenic metal ion content and particle size distribution

Nine cheap eye shadow products were analyzed through graphite furnace atomic absorption spectrometry (GF-AAS) to quantify their Cr, Co and Ni contents, all known to be skin sensitizers. In many cases, the concentrations were higher than 1 or 5 ppm (μg/g), i.e. the limits recommended in the scientific literature to minimize the risk of reaction in particularly sensitive subjects. In most cases, the concentration of Cr was higher than that of Ni and Co, up to a limit case of 150 mg/g. In this particular sample, the potential amount of Cr that could be released in ionic form was determined in sweat simulating solutions by GF-AAS and confirmed through a specific spectrofluorimetric method; the results indicated the presence of approximately 80-90 ppb (ng/g) of Cr(3+). The water dispersible particles were isolated from the eye shadow powders through a simple solvent extraction procedure. The aqueous suspensions were then sorted through sedimentation field flow fractionation (SdFFF) and the particles sizes were calculated from experimental fractograms using theory. For the most part, the computed sizes were in the micron range, as confirmed by some SEM photographs taken on fractions collected during the separations. The SdFFF coupled off-line with the GFAAS enabled elemental characterization of pigment particles as a function of size. This finding reduces the concern that the ingredients of such makeup formulations may contain nanoparticles.

Carcinogenic metals and the epigenome: understanding the effect of nickel, arsenic, and chromium

Carcinogenic metals, such as nickel, arsenic, and chromium, are widespread environmental and occupational pollutants. Chronic exposure to these metals has been connected with increased risks of numerous cancers and as well as non-carcinogenic health outcomes, including cardiovascular disease, neurologic deficits, neuro-developmental deficits in childhood, and hypertension. However, currently the specific molecular targets for metal toxicity and carcinogenicity are not fully understood. Here, we propose that the iron- and 2-oxoglutarate-dependent dioxygenase family enzymes, as well as, other histone modifying enzymes are important intracellular targets that mediate the toxicity and carcinogenicity of nickel, and maybe potential targets in chromium and arsenic induced carcinogenesis. Our data demonstrate that all three metals are capable of inducing post-translational histone modifications and affecting the enzymes that modulate them (i.e. the iron- and 2-oxoglutarate-dependent dioxygenase family, including HIF-prolyl hydroxylase PHD2, histone demethylase JHDM2A/JMJD1A, and DNA repair enzymes ABH3 and ABH2, and histone methyltransferases, G9a). Given the effects that these metals can exert on the epigenome, future studies of their involvement in histone modifying enzymes dynamics would deepen our understanding on their respective toxicities and carcinogenicities.

Concurrent sensitization to metals and occupation

BACKGROUND

Cosensitization to nickel, cobalt and chromium occurs in the general population and in some occupational groups.

OBJECTIVES

To estimate the isolated and concurrent occurrence of nickel, cobalt and chromium contact sensitization and their association with individual and occupational risk factors.

PATIENTS/METHODS

Twelve thousand four hundred and ninety-two patients were patch tested with the European baseline series between 1997 and 2004 in north-eastern Italy. The associations between patch test results and patient characteristics and occupations were investigated by means of multinomial logistic regression analysis.

RESULTS

Of the patients, 34.7% (4334 patients) had one or more positive patch test reactions to metals. As compared with those with negative reactions to all three metals, nickel sensitization was significantly higher in females than in males, not only as monosensitization, but also as cosensitization with cobalt, with chromium, or with both metals. Building and related trades workers showed positive reactions to chromium + nickel [odds ratio (OR) 1.99; 95% confidence interval (CI) 1.05-3.76) and chromium + cobalt (OR 2.61; 95% CI 1.46-4.67]. Cleaning workers showed a high prevalence of nickel, chromium, nickel + chromium and nickel + cobalt + chromium cosensitization (ORs 1.29, 1.66, 2.11, and 1.79, respectively). An excess risk for cosensitization to all three metals was found in textile and leather workers (OR 2.19; 95% CI 1.10-4.33), and in bartenders (OR 2.10; 95% CI 1.03-4.26).

CONCLUSIONS

Some occupational groups are more likely to develop nickel, cobalt and chromium cosensitization.

Concentration of cadmium, mercury, zinc, copper and cobalt in the tissues of wild boar (Sus scrofa) hunted in the western Slovakia

The aim of this study was to monitor accumulation of cadmium (Cd), mercury (Hg), zinc (Zn), copper (Cu) and cobalt (Co) in the muscle, liver and kidney of wild boar (Sus scrofa scrofa) from hunting place of western Slovakia and the correlations among the observed elements. A total of 120 samples were involved for analyses by atomic absorption spectrophotometry (AAS). The significantly highest accumulation of Cd in the kidney followed by the liver and muscles was found. Zn accumulated mainly in the liver. Significantly lower values were found in the kidney followed by the muscle. The concentration of Cu was significantly lowest in the muscle when compared to the liver and kidney. Hg and Co accumulated mainly in the kidney, followed by the liver and muscle of wild boars, but without significant differences. In the muscle of wild boar moderately positive correlation between Zn and Cu (r = 0.59), Cd and Co (r = 0.51), Cu and Co (r = 0.33), and Zn and Hg (r = 0.36) were found. In the liver moderately positive correlation between Cd and Hg (r = 0.39) was detected. Moderately positive correlation between Zn and Cu (r = 0.40) was noted for the kidney.