Current Understanding of Sex Differences in Metal-Induced Diseases

PURPOSE OF REVIEW

The influence of basic biological differences between males and females has been historically overlooked. This is especially true when considering the differences in disease severity and progression brought on by exposure to toxic metals. A current area of interest is understanding how exposure to toxic heavy metals manifests differently in males and females. The present work assesses the potential sex-differences in diseases induced by arsenic, lead, cadmium, and chromium. These specific heavy metals are included in a wealth of literature supporting their induction of diseases that negatively impact health.

RECENT FINDINGS

Arsenic toxicity appears to effect males significantly more than females. This is largely due to males having decreased arsenic methylation ability compared to females. Lead is a potent neurotoxicant that induces developmental and behavioral deficits in young children. While these deficits are seen in both sexes, the specific aspects of behavior and development affected differ between males and females. Research shows females absorb more cadmium from the gastrointestinal tract, correlating with a rich history of cadmium-induced renal dysfunction. Occupational exposure is a significant factor when considering chromium toxicity. Males are much more likely to work in industrial positions where chromium exposure is common, resulting in more males suffering the consequences of chromium exposure than females. Understanding how sex influences the pathogenesis of metal-induced diseases will allow for the elucidation of sex-specific mechanisms, which can be used to create more targeted and effective therapies to treat metal-induced diseases in males and females.

Artificial Intelligence That Predicts Sensitizing Potential of Cosmetic Ingredients with Accuracy Comparable to Animal and In Vitro Tests-How Does the Infotechnomics Compare to Other "Omics" in the Cosmetics Safety Assessment?

The aim of the current study was to develop an in silico model to predict the sensitizing potential of cosmetic ingredients based on their physicochemical characteristics and to compare the predictions with historical animal data and results from "omics"-based in vitro studies. An in silico model was developed with the use of WEKA machine learning software fed with physicochemical and structural descriptors of haptens and trained with data from published epidemiological studies compiled into estimated odds ratio (eOR) and estimated attributable risk (eAR) indices. The outcome classification was compared to the results of animal studies and in vitro tests. Of all the models tested, the best results were obtained for the Naive Bayes classifier trained with 24 physicochemical descriptors and eAR, which yielded an accuracy of 86%, sensitivity of 80%, and specificity of 90%. This model was subsequently used to predict the sensitizing potential of 15 emerging and less-studied haptens, of which 7 were classified as sensitizers: cyclamen aldehyde, N,N-dimethylacrylamide, dimethylthiocarbamyl benzothiazole sulphide, geraniol hydroperoxide, isobornyl acrylate, neral, and prenyl caffeate. The best-performing model (NaiveBayes eAR, 24 parameters), along with an alternative model based on eOR (Random Comittee eOR, 17 parameters), are available for further tests by interested readers. In conclusion, the proposed infotechnomics approach allows for a prediction of the sensitizing potential of cosmetic ingredients (and possibly also other haptens) with accuracy comparable to historical animal tests and in vitro tests used nowadays. In silico models consume little resources, are free of ethical concerns, and can provide results for multiple chemicals almost instantly; therefore, the proposed approach seems useful in the safety assessment of cosmetics.

Patch Testing of Mercaptobenzothiazole and Mercapto Mix: The North American Contact Dermatitis Group Experience, 1994-2016

OBJECTIVES

Mercapto compounds are a category of rubber accelerators that may cause allergic contact dermatitis. This study characterizes patch test reactions to mercaptobenzothiazole (MBT) and mercapto mix (MM) in a large North American population.

METHODS

The 1994-2016 North American Contact Dermatitis Group screening series data were analyzed. Patients with allergic reactions to either MBT or MM (mercapto+) were included. The following characteristics were analyzed: strength of reaction, clinical and occupational relevance, coreactivity with other rubber accelerators, and sources of exposure.

RESULTS

A total of 49,795 patients were tested to mercapto compounds from 1994 to 2016; 633 (1.3%) had positive reactions to MBT and/or MM. The frequency to both MBT and MM significantly decreased over time (P < 0.0001). Mercapto+ patients were significantly more likely to be male, have occupationally related skin disease, and report involvement of the hands and/or feet (P < 0.0001). They were significantly less likely to have face, scalp/ears/neck, or trunk involvement (P ≤ 0.0001). There was significant coreactivity with carba mix (23.4%) and thiuram mix (32.5%). Mercaptobenzothiazole and MM reactions were frequently clinically (81.7% and 83.5%, respectively) and occupationally relevant (29.8% and 33.4%, respectively). Gloves were the most common source (31.3% and 30.9%, respectively).

CONCLUSIONS

Patch test positivity to mercapto compounds significantly decreased from 1994 to 2016 but remains clinically and occupationally relevant.

A perspective on the safety of parabens as preservatives in wound care products

Antimicrobial and/or preservative ingredients incorporated in wound care products are subjected to certain safety restrictions. However, several of those agents, and paraben preservatives in particular, have been criticised. Conflicting reports on the potential of parabens to induce allergic contact dermatitis, and their assumed oestrogen‐like activity, raised public health concerns about their overall safety. Here, we seek to provide a balanced perspective on the most significant purported adverse health effects, and thereby allay the many misconceptions regarding the safety of parabens. Extensive and long‐term monitoring of paraben allergy frequencies illustrate that allergic reactions are quite uncommon, especially when compared with other antimicrobial and preservative agents. The estrogenic potential of parabens was illustrated to be far less potent than that of natural oestrogen receptor ligands, and the etiological significance of their presence in human tissue has not been established. The general consensus based on investigations by both the scientific community and regulatory agencies indicates that, with current safety regulations regarding their use in place, this effective and well‐documented group of preservatives should not warrant drastic measures to replace them. As such, despite the ongoing concern, it is indicated that, when used at typical concentrations, parabens are unlikely to affect human health.

Chromium and leather: a review on the chemistry of relevance for allergic contact dermatitis to chromium

Abstract

As other causes decline in importance, chromium-tanned leather has become a more important source for chromium allergy, which affects around 1% of the general population. The aim of this review is to give suggestions on how to minimize the risk of leather-related allergic contact dermatitis, which can be elicited in chromium-allergic persons by hexavalent and trivalent chromium released from leather. Hexavalent chromium is the more potent chromium form and requires a lower skin dose to elicit allergic reactions. It is formed on the surface of some, antioxidant-free, leathers at dry conditions (< 35% relative humidity) and is influenced by the tanning process and other conditions, such as UV irradiation, contact with alkaline solutions, and leather age. Trivalent chromium is the dominant form released from chromium-tanned leather and its released amount is sufficient to elicit allergic reactions in some chromium-allergic individuals when they are exposed repetitively and over longer time (days – months). A low initial test result (< 3 mg/kg) for hexavalent chromium with the current standard test (ISO 17075) does not guarantee a low release of chromium from the leather or a low release of hexavalent chromium under typical exposure conditions during the service life of the leather. Information, labels, and certificates regarding leather products are often insufficient to protect chromium-allergic individuals. Correct labelling and information on the possible content of different allergens, as well as different tanning alternatives for certain leather products, are crucial.

Graphical abstract

Patch testing in Lao medical students

Background

Dermatological services in Laos, South East Asia are limited to the capital and patch testing is currently not available, so no data exists regarding the common cutaneous allergens in this population.

Objectives

The aim of this study was to document positive patch tests in medical students without evidence of contact dermatitis in Laos.

Patients/Materials/Methods

One hundred and fifty medical students were patch tested using TRUE Test^® panels 1 to 3 (35 allergens). Readings were taken at Days 2 and 4.

Results

Thirty-eight students (25.3%) had a positive reaction to at least one allergen, accounting for 52 reactions in total. The proportion of the students with positive patch test reading was significantly higher in the female [33/96 (34%)] than in the male [5/54 (9%)], p<0.001. The most common allergens were: nickel (10%), gold (6.6%), thiomersal (6.6%), cobalt dichloride (2%) and p-tert-Butylphenol formaldehyde resin (2%). Balsam of Peru (0.66%), black rubber mix (0.66%), Cl+Me-Isothiazolinone (0.66%), fragrance mix 1 (0.66%), quinolone mix (0.66%), methyldibromo glutaronitrile (0.66%), mercapto mix (0.66%), epoxy resin (0.66%), paraben mix (0.66%), thiuram (0.66%) and wool alcohols (0.66%) accounted for all of the other positive reactions.

Conclusion

This study represents the first documented patch test results in Lao medical students and in the adult Lao population. The results of this study will inform any future research into contact allergy in Laos and give an insight into the background level of contact sensitivity in this population.

Epidemiology of nickel sensitivity: Retrospective cross-sectional analysis of North American Contact Dermatitis Group data 1994-2014

BACKGROUND

Nickel is a common allergen.

OBJECTIVE

To examine the epidemiology of nickel sensitivity in North America.

METHODS

Retrospective, cross-sectional analysis of 44,097 patients patch tested by the North American Contact Dermatitis Group from 1994 to 2014. Nickel sensitivity was defined as a positive patch test for nickel. We evaluated the frequency of nickel sensitivity and patient demographics. For each positive reaction to nickel, we tabulated clinical relevance, occupational relatedness, and exposure sources.

RESULTS

The average frequency of nickel sensitivity was 17.5% (1994-2014). Nickel sensitivity significantly increased over time (from 14.3% in 1994-1996 to 20.1% in 2013-2014 [P < .0001]). Nickel-sensitive patients were significantly more likely to be female, young, nonwhite, and atopic (have eczema and asthma) and/or have dermatitis affecting the face, scalp, ears, neck, arm, or trunk (P values ≤ .0474). Overall, 55.5% of reactions were currently clinically relevant; this percentage significantly increased over time (from 44.1% in 1994-1996 to 51.6% in 2013-2014 [P < .0001]). The rate of occupational relatedness was 3.7% overall, with a significant decrease over time (from 7.9% in 1994-1996 to 1.9% in 2013-2014 [P < .0001]). Jewelry was the most common source of nickel contact.

LIMITATIONS

Tertiary referral population.

CONCLUSIONS

Nickel allergy is of substantial public health importance in North America. The frequency of nickel sensitivity in patients referred for patch testing has significantly increased over a 20-year period.

Erythema papulosa semicircularis recidivans: a new reactive dermatitis?

BACKGROUND

Nine patients with recrudescent and centrifugally expanded papuloerythematous eruptions were observed in our outpatient department during the recent 8 years. The patients were all young and middle-aged men presenting with characteristic skin lesions and relapsing each year in the warm humid season. Such an observation has not yet been described in the English literature.

OBJECTIVES

The objective of this study was to describe the clinical characteristics and explore the possible etiologies of our cases. In addition, differential diagnosis with other common figurate erythemas was also reviewed and discussed.

METHODS

In 5 of the patients, skin-prick testing was performed with common airborne and food allergens, and skin patch testing with the Chinese baseline series of contact allergens was performed, along with histopathologic examinations.

RESULTS

The skin findings in our patients were conspicuous in their papular characteristics of the borders, semicircular arrangement, male predominance, and yearly crescendo of recurrence in warm seasons. Histopathologic examination showed superficial perivascular dermatitis, whereas skin-prick testing and patch testing showed negative results.

CONCLUSIONS

Although the etiology of our cases remains unclear at present, the clinical characteristics make them distinct from other well-described figurate erythemas characterized by annular erythematous lesions. We propose the term erythema papulosa semicircularis recidivans to depict a special form of recurrent papuloerythematous figurate erythema of unknown etiology.

Urinary levels of nickel and chromium associated with dental restoration by nickel-chromium based alloys

This paper aims to investigate if the dental restoration of nickel–chromium based alloy (Ni–Cr) leads to the enhanced excretions of Ni and Cr in urine. Seven hundred and ninety-five patients in a dental hospital had single or multiple Ni–Cr alloy restoration recently and 198 controls were recruited to collect information on dental restoration by questionnaire and clinical examination. Urinary concentrations of Ni and Cr from each subject were measure by graphite furnace atomic absorption spectrometry. Compared to the control group, the urinary level of Ni was significantly higher in the patient group of <1 month of the restoration duration, among which higher Ni excretions were found in those with either a higher number of teeth replaced by dental alloys or a higher index of metal crown not covered with the porcelain. Urinary levels of Cr were significantly higher in the three patient groups of <1, 1 to <3 and 3 to <6 months, especially in those with a higher metal crown exposure index. Linear curve estimations showed better relationships between urinary Ni and Cr in patients within 6-month groups. Our data suggested significant increased excretions of urinary Ni and Cr after dental restoration. Potential short- and long-term effects of Ni–Cr alloy restoration need to be investigated.