Health and safety hazards associated with cleaning agents

John Durkee Ph.D., P.E. , in Direction of Industrial Cleaning Applied science and Processes, 2006

3.10.5.i First Line of Defense

The homo body possess number of physical and chemical barriers that prevent entry of pathogens or hazardous chemicals (Effigy three.27).

Figure iii.27. UK corrosive symbol

Of these, perhaps the well-nigh important physical barrier is the skin. The skin consists of two singled-out layers: a relatively sparse outer epidermis and a thicker layer, the dermis.

The epidermis consists of several layers of tightly packed epithelial cells that are dead and filled with a water-proof protein chosen keratin. Therefore, it acts as a concrete bulwark confronting entry of chancy chemicals into the body.

The dermis contains a gland, called the sebaceous gland, that produces an oily secretion called sebum. Sebum consists of number of organic acids that maintain the pH of the skin betwixt 3 and five. 116

Therefore, intact skin non simply prevents entry of pathogens or hazardous chemicals but also inhibits the growth of most pathogenic bacteria due to its low pH. 117

Yet, the pare does non cover the unabridged surface of the human body. Conjunctiva of the heart, alimentary, respiratory, and urinogenital tracts are not covered by dry, protective skin but by mucous membranes. Therefore, these places function equally potential entry sites for pathogens or hazardous chemicals.

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MASS SPECTROMETRY | Electron Impact and Chemical Ionization

Due east. Eljarrat , D. Barceló , in Encyclopedia of Belittling Science (Second Edition), 2005

Lanolin steryl ester determinations

Lanolin is the wool grease secreted by the sheep sebaceous glands, and represents a complex mixture of high molecular mass lipids, including fatty acids and alcohols, sterols, hydroxyacids, diols, and aliphatic and steryl esters. Lanolin is widely used in cosmetic and pharmaceutical formulations. The written report of minor lipids has shown involvement in club to assess the quality and authenticity of cosmetic and pharmaceutical products and also the steryl esters take already been used to bear witness the authenticity of eatable oil.

Those compounds have been reported equally difficult to analyze due to their loftier molecular mass and poor information given past EI–MS. Also, the isomers normal, iso, and anteiso take been identified for each family past means of chromatographic retentiveness information. A comparison between different ionization techniques has been carried out in order to optimize target compound identification. EI–MS has shown to be the most sensitive only providing poor structural information for cholesteryl esters not permitting to identify the acrid moiety or molecular ion. On the other hand, CI offered the all-time results in terms of structural information obtained in the PCI with ammonia equally reagent gas.

Several examples showed the suitability of CI versus EI in order to reach a satisfactory separation between isomers. However, there are as well some examples demonstrating that EI afforded amend structural information. Fully acetylated methyl x-deoxy-x-fluoro-α-d-glucopyranosides have been studied using EI and ammonia CI. Feature differences in the fragmentation of positional isomers were noted on assay of the spectra, and these make it possible to determine the location of fluorine in the molecules. Fragmentation of [M−OCHiii]+ ions produced past EI provides an alternative method for localization of the fluorine atoms. On the reverse, spectra of [M+NH4]+ cluster ions produced past CI did non beget such structural information.

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Toxicokinetic aspects of nerve agents and vesicants

Harald John , ... Horst Thiermann , in Handbook of Toxicology of Chemical Warfare Agents (Third Edition), 2020

52.two.1.2 Dermis

The dermis (corium) consists of connective vascularized tissue composed of collagen, elastic and reticular fibers anchoring sweat and sebaceous glands, and pilus follicles. Capillaries pervading the dermis and hypodermis (subcutis, located beneath the dermis) permit systemic distribution of toxic compounds once they have passed the epidermis. Therefore, percutaneously incorporated poison may exist directly transported by circulation to whatsoever compartment of an organism, or it may be temporarily retained inside the pare layers. In add-on, information technology might penetrate with first-society kinetics into subcutaneous tissues and muscles, thus creating a poisonous substance depot for delayed release ( Wolthuis et al., 1981; Chilcott et al., 2005). If nerve agents are kept in fatty tissue, degradation by biotransformation appears rather unlikely, thus maintaining an active release system (Sweeney et al., 2006). Correspondingly, Van der Schans et al. (2003) reported that it took more than 3   h to reach a maximum concentration in blood of lipophilic VX later percutaneous administration of 1×LD50 to hairless republic of guinea pigs (see Section 52.38).

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Selamectin

G.G. Fent , in Encyclopedia of Toxicology (Tertiary Edition), 2014

Toxicokinetics

Following dermal awarding, selamectin is apace absorbed from skin into the bloodstream from which it is excreted into the gastrointestinal tract and selectively distributed into the sebaceous glands of the pare. This reservoir of selamectin in the pare is responsible for the drugs activity against fleas, ticks, ear mites, and sarcoptic mange mites. The presence of selamectin in the bloodstream and gastrointestinal tract are responsible for its action against heartworm microfilaria and intestinal parasites, respectively. Active concentrations of selamectin persist in the plasma for at least 30 days following awarding. Excretion occurs predominantly via the carrion, but small amounts of unmetabolized drug tin be found in the urine.

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Including Actinides

Giada Truccolo , ... William J. Gee , in Handbook on the Physics and Chemistry of Rare Earths, 2020

iv.2 Fingerprint chemistry

The initial composition of a latent fingerprint is a circuitous mixture of peel secretions and contaminants [108] . About prominent are the secretions from the eccrine and sebaceous glands. Eccrine glands are the glands nowadays across the body, in loftier density on the palms of the easily and soles of the anxiety. Sweat produced by these glands is predominantly water containing amino acids, salts, urea, and other organic and inorganic compounds. Sebaceous glands are located amongst hair follicles so are present in highest density on the head. Sebum, a mixture of oils and waxes produced to keep hair follicles healthy is oft incorporated inside fingerprint residue due to natural contact between hands and hair on the body [109,110]. Naturally, secretions from the eccrine glands brand up a meaning corporeality of fingerprint residue, however recent research has suggested the presence of both sebaceous and eccrine material as an emulsion, with the verbal proportion of eccrine to sebaceous textile existence donor and sample dependent [111].

Contaminants can provide a unique level of information within a fingerprint sample, with dead pare cells providing the opportunity to generate Dna profiles, whilst other contaminants can advise an private's activities prior to fingerprint deposition [112]. Corrective products such as skin lotions, sunscreens and beauty products accept been identified in fingerprint residues, demonstrating their persistence on the surface peel and their transferability to fingerprint samples [113]. Contaminants such as illicit drugs, gunshot residue and material from improvised explosive mixtures can also be transferred inside fingerprint remainder, these components pose as interesting chemic targets for detection methods equally well equally potentially straight linking a sample to a item type of criminal activity [114,115]. Due to their ease of transferability these surface contaminants tin can also be cross-contaminated through contact betwixt people or a surface.

The complexity of fingerprint chemical science is challenged farther by the variation betwixt individuals [116]. Donor characteristics including biological sex, age, ethnicity, diet, and medication can all influence the initial composition of fingerprint residue. Age and biological sex have shown to influence the composition of pare secretions, with studies reporting noticeable differences betwixt the chemical composition of children versus developed fingerprints [117]. Traces of orally administered medications have been detected in the eccrine sweat of patients, suggesting the potential for medication or illicit drug use to be detected through fingerprint residues, whilst diets such every bit high/low calorie, vegetarian, seafood and dairy-gratis tin can impact sweat and surface skin lipid limerick [118,119]. Studies accept explored the effects these traits tin accept on fingerprint residue composition; withal farther research is required before these traits can be used for identification purposes.

To farther complicate fingerprint chemistry, intra-donor variation, that is the variation betwixt fingerprint deposits from an individual, tin can be observed. Intra-donor variation in chemic composition has been debated, with limited studies expressing contradictory views on whether there is a statistically significant change in composition [120,121]. Deposition conditions such as force per unit area, duration, deposition surface, time of day and hand care can influence the limerick of fingerprint remainder, particularly the quantitative amounts nowadays. Whilst studies have been unable to show statistical proof of these factors effecting fingerprint limerick, the potential effects are something that should aim to exist controlled to limit intra-donor variation. Dorakumbura et al. suggests a recommended deposition process to limit intra-donor variation, donors should wash their hands with liquid soap for 2   min, air dry and and so engage in regular activities for 30   min without subsequent washing of hands, handling food or chemicals [122]. Donors should rub hands together to evenly distribute material on the surface of the peel earlier depositing their fingerprints whilst maintaining a constant force per unit area and deposition time.

Latent fingerprint composition is not static and, following degradation, changes from the initial composition are observed. As evidence, fingerprints are often not recovered from a crime scene immediately post-obit deposition, so information technology is of import for fingerprint researchers to sympathize how fingerprint composition changes with time. In that location are fingerprint development methods which are more effective on fresh fingerprints, with efficacy changing as the fingerprint ages. By better understanding the rate and procedure of fingerprint aging we can determine how this furnishings fingerprint chemistry and improve detection methods.

The initial limerick and environmental conditions of a fingerprint have greatest influence on the aging procedure. After degradation volatile substances are first lost, including the water content in the fingerprint, this may exist a significant loss if the fingerprint is eccrine rich [123]. The resulting composition of non-volatile lipids and salts tin can undergo further change over an extended menstruation. Components such as lipids, free fat acids and wax esters can undergo degradation forming by-products, altering the fingerprint composition farther [124,125]. Some researchers have looked at the dating of fingerprints by looking at these by-products, all the same without knowing the exact environmental conditions the fingerprint has been stored in, which is unrealistic for forensic investigations, a precise date cannot be determined. This is because the rate of degradation can vary greatly dependent on the environment the fingerprint has been stored in.

The following conditions are some of the ecology factors which can vary the fingerprint aging process; temperature, humidity, light exposure, water exposure, airflow and atmospheric contaminants [126]. There are limited studies reported that seek to understand the impact of these conditions on fingerprint rest, with large scale studies required to explore these conditions due to the variability in initial fingerprint composition. The exposure to light, airflow and temperature accept been investigated to improve sympathize the degradation process of specific components within fingerprint residuum, especially the effects on degradation rates [127,128]. Whilst in that location are no strict recommendations for the best environment to store fingerprint samples, consistency is vital when assessing a development method. Researchers should be enlightened of the potential for environmental impacts on fingerprint aging, including consideration for the type of development method based off the environs the fingerprint is stored, for case deposits exposed to h2o should be treated differently to a sample which is kept dry out.

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Book 2

Igor Kogut , Ganna Bilousova , in Encyclopedia of Tissue Applied science and Regenerative Medicine, 2019

Last Remarks

Pare is a unique organ with remarkable regenerative properties. Skin regeneration is maintained past several subpopulations of epidermal stalk/progenitor cells localized within their specialized niches in the IFE, HF, SG, and sweat glands. The evolution of epidermal progenitors occurs as a consequence of complex epithelial–mesenchymal interplay and is regulated past a subset of signaling pathways, as well as cell–cell and prison cell–ECM interactions. Despite all-encompassing research, our knowledge of skin evolution is just emerging. The evolution of lineage-tracing mouse models was particularly beneficial in elucidating the factors affecting epidermal stem cell development. This knowledge is now being implemented in the in vitro differentiation of ESCs and iPSCs into epidermal progenitors. Because of their limitless self-renewal capacity and power to differentiate into any cell types in the body, ESCs and iPSCs are invaluable for in vitro studies of lineage development, disease modeling and potential cell replacement therapies. PSCs can as well exist useful for the development of complex 3D skin equivalents for research and clinical applications. Unfortunately, current 3D skin equivalents derived from PSCs recapitulate only the bones compages of the skin and practise not incorporate pare appendages, such every bit HF, SG and sweat glands. An enhanced understanding of signaling inputs and extrinsic cues regulating the development of skin appendages volition allow the researchers to reconstitute these important peel structures in a 3D skin-modeling platform. This will further improve the survival and functionality of in vitro-generated skin upon transplantation into patients and will also answer basic questions related to human skin development and physiology that cannot exist addressed solely in the context of monolayer tissue cultures or animal models.

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Nanoscale Titanium Dioxide: Environmental Health and Ecotoxicological Furnishings

C. Chen , J. Wang , in Encyclopedia of Environmental Wellness, 2011

Dermal uptake

The skin, the largest organ of animals, is a mechanical barrier to infection and stimuli. However, some nutrients, hormones, and synthetic drugs are absorbed through the corneum, sebaceous gland, and orifice of hair follicle. NPs are small enough that, after improving their surface lipophilic belongings, they can penetrate the uppermost layer of skin into the body. This is the example with the nanoscale TiO 2 particles, selected for use in sunscreens, cosmetics, and personal intendance products for their efficient absorption and physical reflection of UV low-cal. A study reported that microsized TiOii used in cosmetics homogeneously and completely covered the outermost consummate corneum layer of pare. However, TiO2 particles cannot be delivered to the underlying peel layers using the excised porcine skin for in vitro study. Using the spatially resolved ion axle analytical technologies (photon-induced 10-ray emission, PIXE, and Rutherford back scattering, RBS), researchers institute that TiOii particles (45–150   nm long and 17–35   nm wide) could penetrate through the stratum corneum of pig skin and into the underlying stratum granulosum via the intercellular infinite, non the pilus follicles. However, some studies point that pilus follicles and pores are a 'repository,' and thus are the main penetration pathways when TiO2 particles are applied to human being hairy skin. To farther assess the pathway of dermal penetration and the toxicological effect of NPs on peel, the fluorescent microspheres, such as breakthrough dots or fluorescent-coated NPs, are the preferred materials to notice the NP content of each layer of skin.

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Pare

P.J. Robinson , in Encyclopedia of Toxicology (Tertiary Edition), 2014

Skin Response to Captivated Chemicals

There are many fundamental questions concerning skin assimilation and metabolism that remain to be addressed. The potential role of the dermal vasculature, the contribution of pare appendages such equally hair follicles and sebaceous glands, the influence of skin condition, age, disease state, and anatomic sites are merely a few examples of questions that need to be resolved. When topical exposure results in local effects, pathological changes in the skin may be expected to affect its barrier functions. These changes may involve alteration of the concrete bulwark also as the biochemical properties, such every bit the metabolic status of the skin. Such local changes may have of import implications on the consequence of percutaneous absorption and fate of topically applied xenobiotics. The experimental techniques necessary to address these questions are available, and productive research in these areas volition provide means whereby species differences in peel absorption and metabolism may be investigated. These studies should provide not simply a meliorate agreement of the mechanisms important in the percutaneous fate of topically practical chemicals but also a rational ground for cross-species extrapolation and, therefore, more predictive estimates for skin absorption and metabolism in man.

We now turn from determining the fate of chemicals absorbed into and through the skin to exploring the biological responses of the skin to the presence of xenobiotics. Such responses include various immune responses, chemically induced pare irritation, burns, and tumor formation discussed in item in the 2nd half of this chapter. For now, as an introduction to potential dermal health effects, we will discuss some methods for identifying diverse cellular response pathways potentially altered by the presence of foreign chemicals in the skin. The direct interaction of chemicals with cellular and molecular constituents within the skin tin lead to tissue toxicity, depending on the tissue dose (local concentration and time of exposure) and the authorization (toxicity) of the chemical.

The study of factor expression studies has become a useful approach to enhance the agreement of this initial response of the skin to xenobiotics. Analysis of such data may lead to the development of a 'molecular signature' characteristic of chemical-induced dermal injuries. Equally biological systems are carefully controlled by cellular poly peptide effectors, changes in normal functions would be expected to be reflected in the process of increased or decreased messenger ribonucleic acid (mRNA) expression and subsequent protein synthesis. Gene expression technology has progressed to the phase where thousands of transcripts can be characterized from a unmarried tissue sample using gene array techniques, the level of mRNA transcripts in both normal and perturbed skin should give some indication of the relative proportion and importance of each of these functions. Since skin consists of multiple jail cell types in communication with each other, it is of import to expect at whole skin in such studies to get a complete moving-picture show of the molecular response. In improver, these gene expression profiles can provide valuable insight into the evolution of rubber and/or therapeutic treatments targeting specific molecular pathways or genes that could reduce the debilitating furnishings of chemical exposure to the skin, reduce disease severity, or promote wound healing. Factor array engineering science has been used to monitor expression patterns in whole skin, three-dimensional cultures, keratinocytes, dermal fibroblasts, Langerhans cells, melanocytes, and skin-derived mast cells. These studies have helped define feature gene expression patterns that reflect pare responses over a broad range of external insults and/or stimuli.

Cellular responses to a xenobiotic in the skin depend on its concentration–time profile at the specific location (depth) within the skin of the target jail cell blazon. To fully empathize the peel's molecular response, nosotros therefore ideally need to combine gene expression time-course data with some notion of the chemic'due south disposition inside the peel as a role of time. In other words, the human relationship between the time course of local chemical concentration in the pare and resultant changes in gene expression with time needs to be explored. Thus, more than detailed models of the movement of chemicals inside the skin need to exist developed that take into account the heterogeneities, different cell types, etc. Such models, for case, may exist developed in terms of partial differential equations, with the concentration of the chemic described equally a office of both the time and its location within the skin. Equally the chemical diffuses into the skin from a finite applied dose, in general it will also lengthened out laterally from the site of exposure. Thus, in order to predict concentrations within a detail cell type (or even within a specific sub-compartment of the cell), we require quantitative models of considerable complexity, beyond anything described earlier in this chapter. To develop and validate such models, experimental techniques such as microdialysis that allow measurement of concentrations at specific locations in the skin volition be needed. In addition, correlations with transcriptomic and associated biomarker information volition also assistance support such models.

Exposure to chemicals leads to patterns of gene expression that change with fourth dimension, concentration, and, of class, the nature of the chemical itself. However, xenobiotics generally interact with the skin via a number of common pathways, associated for example with cell death, cellular growth and proliferation, cellular movement, inflammation, and metabolism, ultimately leading to the common toxic responses described in the next section. Meta analyses of transcriptomic data may lead to the identification of a more than generalized set of biochemical responses and biomarkers that could pb to the characterization of these chemically induced skin injuries and responses, fifty-fifty at very early times following exposure, or at very low doses before overt signs of toxicity go credible. Focusing on the specific genes within these functions and pathways may provide the all-time approach to place molecular targets to mitigate the toxic effect of a particular chemical. For example, exposure of skin to (irritating) hydrocarbon mixtures (fuels) have led to increases in gene expression for, also equally the advent of the pro-inflammatory mediators tumor necrosis factor (TNF) and interleukin-vi (IL-6), which may ultimately bear witness to exist indicative of common mechanisms for chemically induced pare irritation.

The next section discusses the biological response of skin tissue to dermally captivated chemicals in more detail.

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Dibenz[a,h]anthracene

S. Bhattacharya , ... Due south.Southward. Roy , in Encyclopedia of Toxicology (Third Edition), 2014

Creature

Dibenz[a,h ]anthracene showed no subacute toxic effect in marine animals, only showed some growth inhibition and prenatal toxicity in rats. Every bit an indicator of potential carcinogenic activity, loftier levels of sebaceous gland suppression were seen when dibenz[ a,h]anthracene was practical twice daily on three consecutive days to the peel of mice. Subcutaneous injections of 0.278 mg dibenz[a,h]anthracene 5 times weekly in rats for several weeks exhibited pathological changes in the lymphoid tissues, which were characterized past extravascular carmine claret cells in the lymph spaces and by the presence of abnormally large pigmented cells.

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Pesticide Excretion

Ernest Hodgson , in Pesticide Biotransformation and Disposition, 2012

Obscure Routes of Excretion

Because passive diffusion of lipophilic toxicants may occur across whatever prison cell membrane, it might be expected that such chemicals volition appear in many trunk secretions, such every bit sweat, or in growth products, such equally hair, nails, and peel. The sebaceous glands secrete an oily secretion and, probably for this reason, insecticides and PCBs take been establish in homo hair. Arsenic, mercury, and selenium have also been associated with hair.

Although such routes of excretion are probably just a minor proportion of the full excretion of any particular xenobiotic, they may provide a noninvasive method of estimating exposure or total body burden. Analysis of bird feathers is useful for the cess of heavy-metal exposure, and the amount of cotinine, a major metabolite of nicotine, in saliva has been used extensively as a biomarker for nicotine uptake. The excretion of atrazine in saliva has also been tested in rats as a potential biomarker of exposure in exposed workers (Lu et al., 1997).

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