Scientific Study into the toxicity of Sodium Lauryl Sulfate

Variations in the mRNA expression of inflammatory mediators, markers of differentiation and lipid-metabolizing enzymes caused by sodium lauryl sulphate in cultured human keratinocytes.

* Torma H,
* Geijer S,
* Gester T,
* Alpholm K,
* Berne B,
* Lindberg M.

Department of Medical Sciences, Uppsala University, Dermatology and Venereology, Akademiska sjukhuset, SE-751 85 Uppsala, Sweden.

Detergents are well known irritants. Effects of the detergent sodium lauryl sulphate (SLS) on cell toxicity using the XTT assay and mRNA expression of inflammatory mediators, markers of keratinocyte differentiation and enzymes synthesizing barrier lipids using real-time PCR were studied in cultured differentiated keratinocytes. After exposure for 24 h to SLS concentrations at 0.002% or above, toxic effects were observed. When a lower SLS concentration (0.00075%) was used the mRNA expression of inflammatory mediators peaked around 4-8 h. The expression of enzymes involved in the synthesis of cholesterol, fatty acids and ceramides and markers of keratinocyte differentiation also increased but after 24 h. In cells exposed to 0.000125-0.0015% SLS, a concentration-dependent induction of the expression of inflammatory mediators was found after 4 h. Similar changes were found after 24 h for involucrin and enzymes involved in ceramide synthesis. The mRNA expression of HMG-CoA synthase and reductase, long-chain acyl-CoA synthase and transglutaminase also peaked after 24 h, but maximal induction was observed already at 0.00075% SLS. In conclusion, SLS induces an inflammatory response in keratinocytes and alters the mRNA expression of important barrier lipid enzymes and markers of keratinocyte differentiation, of possible importance for the irritant properties of SLS.

Translation into English: This stuff is bad, no, very bad news.


Scientivic Study into toxicity of Methylisothiazolinone (MIT)

In vitro neurotoxicity of methylisothiazolinone, a commonly used industrial and household biocide, proceeds via a zinc and extracellular signal-regulated kinase mitogen-activated protein kinase-dependent pathway.

* Du S,
* McLaughlin B,
* Pal S,
* Aizenman E.

Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261, USA.

Neurodegenerative disorders in humans may be triggered or exacerbated by exposure to occupational or environmental agents. Here, we show that a brief exposure to methylisothiazolinone, a widely used industrial and household biocide, is highly toxic to cultured neurons but not to glia. We also show that the toxic actions of this biocide are zinc dependent and require the activation of p44/42 extracellular signal-regulated kinase (ERK) via a 12-lipoxygenase-mediated pathway. The cell death process also involves activation of NADPH oxidase, generation of reactive oxygen species, DNA damage, and overactivation of poly(ADP-ribose) polymerase, all occurring downstream from ERK phosphorylation. The toxic effects of methylisothiazolinone and related biocides on neurons have not been reported previously. Because of their widespread use, the neurotoxic consequences of both acute and chronic human exposure to these toxins need to be evaluated.

PMID: 12196562 [PubMed - indexed for MEDLINE]

Translation into English: Has the potential to cause developmental problems in unborn babies.


Scientific Study into the toxicity of Paraben

Environmental oestrogens, cosmetics and breast cancer.

* Darbre PD.

School of Biological Sciences, The University of Reading, P.O. Box 228, Whiteknights, Reading RG6 6AJ, UK.

The established role of oestrogen in the development and progression of breast cancer raises questions concerning a potential contribution from the many chemicals in the environment which can enter the human breast and which have oestrogenic activity. A range of organochlorine pesticides and polychlorinated biphenyls possess oestrogen-mimicking properties and have been measured in human breast adipose tissue and in human milk. These enter the breast from varied environmental contamination of food, water and air, and due to their lipophilic properties can accumulate in breast fat. However, it is emerging that the breast is also exposed to a range of oestrogenic chemicals applied as cosmetics to the underarm and breast area. These cosmetics are left on the skin in the appropriate area, allowing a more direct dermal absorption route for breast exposure to oestrogenic chemicals and allowing absorbed chemicals to escape systemic metabolism. This review considers evidence in support of a functional role for the combined interactions of cosmetic chemicals with environmental oestrogens, pharmacological oestrogens, phyto-oestrogens and physiological oestrogens in the rising incidence of breast cancer.

PMID: 16522524 [PubMed - indexed for MEDLINE]

Translation into English: These may or may not be harmful, but it is better not to expose yourself to these chemicals


Scientific Study into the toxicity Diazolidinyl Urea

Effects of the formaldehyde releasing preservatives dimethylol urea and diazolidinyl urea in several short-term genotoxicity tests.

* Pfuhler S,
* Wolf HU.

Abteilung Pharmakologie und Toxikologie der Universitat Ulm, Albert-Einstein-Allee 11/N26-428, D-89069, Ulm, Germany.

The two formaldehyde (FA)-releasers dimethylol urea (DMU) and diazolidinyl urea (DZU) are widely used as preservatives or additives. They were tested for genotoxicity in three short-term test systems, i.e. in the Salmonella typhimurium mutagenicity assay, in the in vitro micronucleus test with V79 Chinese hamster cells and in the in vitro tubulin assembly assay using isolated tubulin from pig brains. The polymerization products obtained in the tubulin assembly assay were examined additionally by electron microscopy.In the S. typhimurium mutagenicity assay with the pre-incubation assay both FA-releasers tested show a clear and concentration-dependent increase in the number of revertants in strains TA98, TA100 and TA102 with and without metabolic activation (rat liver S9 mix). In all cases, a biologically relevant increase in the number of revertants was achieved within the concentration range tested (DZU: 0.04-1.8 micromol per plate, DMU: 0.21-8.33 micromol per plate). FA was tested at 0.06-2.5 micromol per plate and lead to similar effects.Both compounds induce the formation of micronuclei (concentration range tested: DZU: 2.5-50 micromol/l, DMU: 3.3-333 micromol/l). However, DMU shows a comparatively weaker effect exclusively in the absence of the metabolizing enzymes. By contrast, DZU yields a distinct increase of the micronucleus rate in the absence and in the presence of S9. In addition, DZU predominantly causes an increase of large micronuclei, which suggests that this compound has a marked aneugenic potential. Cytotoxic effects accompany the clastogenic effects of both DMU and DZU.The examination of DMU and DZU in view of a possible aneugenic potential in the tubulin assembly assay yielded the following results: DMU at concentrations up to 10 mmol/l did not influence the formation of microtubuli, whereas DZU inhibited this process completely at 3 mmol/l. FA at 6 mmol/l completely inhibited the tubulin assembly. These results could clearly be confirmed by electron microscopy examination. The different potential of the two compounds with respect to the inhibition of tubulin formation is apparently due to a significant difference in the degree of FA release.According to these results, both compounds have to be considered as genotoxic in vitro. On account of these data and because of the widespread use of these two compounds in various products used in daily life, a reevaluation of the risk associated with these compounds seems to be necessary.

PMID: 11815252 [PubMed - indexed for MEDLINE]

Translation into English: These substances may cause problems in the formation of your DNA - stay away from this stuff!!


Scientific Study into the toxicity of Petrolium Jelly

Petrolium Jelly Common commercial cosmetic products induce arthritis in the DA rat.

* Sverdrup B,
* Klareskog L,
* Kleinau S.

Department of Medicine, Rheumatology Unit, Karolinska Institute, Stockholm, Sweden.

Many different agents, including mineral oil and silicone, have the capacity to act as immunological adjuvants, i.e., they can contribute to the activation of the immune system. Some adjuvants, including mineral oil, are known to induce arthritis in certain strains of rats after intradermal injection or percutaneous application. The aim of this study was to determine if common commercial cosmetic products containing mineral oil could induce arthritis in the highly susceptible DA (Dark Agouti) rat. Intradermal injection of five out of eight assayed cosmetic products without further additives resulted in arthritis with synovitis. One of the products induced a very aggressive arthritis, which had declined after 5-9 weeks. When this product was also assayed for arthritogenicity upon percutaneous administration, it induced a mild and transient arthritis in 5 out of 10 DA rats, whereas control animals showed no clinical signs of joint involvement. No arthritic reaction was seen in rats after peroral feeding with the most arthritogenic product or by intravaginal application of Freund's adjuvants. Silicone gel implants in DA rats did not cause arthritis. We conclude that mineral oils included in common commercially available products retain their adjuvant properties and are arthritogenic in the presently investigated arthritis-prone rat strain. There is yet no evidence that mineral oils present in cosmetics may contribute to arthritis in humans, but we suggest that this question should be subject to further investigation.

PMID: 9417771 [PubMed - indexed for MEDLINE]

Translation into English: Stay away from this stuff - It won't do you any good, even if it may not harm you.



Scientific Study into the toxicity of DEA (diethanolamine).

Postnatal development of rat pups after maternal exposure to diethanolamine.

* Price CJ,
* Marr MC,
* Myers CB,
* Jahnke GD.

Life Sciences and Toxicology, RTI International, Research Triangle Park, North Carolina 27709-2194, USA.

BACKGROUND: Diethanolamine (DEA), a widely used surfactant, was administered to pregnant mice at the oral LD10 (This is The Dose or Strength, where 10 individuals from 100 die) resulting in failure of pups to grow and thrive through postnatal day (PND) 3 [National Toxicology Program, 1987; York et al., Teratology 37:503-504, 1988]. The toxicity profile for DEA differs among rodent species. This study investigated DEA-induced postnatal toxicity in a second species.

METHODS: Timed-mated Sprague-Dawley rats were dosed (0, 50, 125, 200, 250, or 300 mg DEA/kg/day, p.o.) on gestational days (GD) 6-19. Dams and pups were monitored for body weight, feed/water intake, clinical signs, litter size, and sex ratio. At necropsy (PND 21), maternal liver and kidney weights and number of uterine implantation sites were recorded.

RESULTS: The high-dose group was terminated early due to excessive toxicity. The estimated maternal LD10 was 218 mg/kg/day. Maternal effects included decreased body weight and relative feed intake (>or=200 mg/kg/day), transiently reduced relative water intake (125 and 250 mg/kg/day), and increased absolute kidney weight (>or=125 mg/kg/day). Postimplantation loss (PND 0) and pup mortality (PND 0-4) were increased (>or=200 and >or=125 mg/kg/day, respectively). Pup body weight was reduced (>or=200 mg/kg/day) as late as PND 21.

CONCLUSIONS: This study demonstrates reduced postnatal growth and survival in a second species after gestational exposure to DEA, persistence of toxic effects through the end of lactation, possibly due to long elimination half-life, and maternal and developmental toxicity no-observed-adverse-effect level (NOAELs) (50 mg/kg/day) and lowest-observed-adverse-effect level (LOAELs) (125 mg/kg/day) for oral DEA exposure during embryo/fetal development in the rat. Copyright (c) 2005 Wiley-Liss, Inc.

Translation into English: This stuff is darn toxic.



Scientific Study into the toxicity of Synthetic Colours

Mechanisms of chemical injury of thyroid gland.

* Capen CC.

Department of Veterinary Pathobiology, Ohio State University, Columbus 43210.

Many goitrogenic xenobiotics that increase the incidence of thyroid tumors in rodents exert a direct effect on the thyroid gland to disrupt one of several steps in the biosynthesis and secretion of thyroid hormones. This includes 1) inhibition of the iodine-trapping mechanism (thiocyanate or perchlorate), 2) blockage of organic binding of iodine and coupling of iodothyronines to form thyroxine (T4) and triiodothyronine (T3) (e.g., sulfonamides, thiourea, methimazole, and aminotriazole, among others), and 3) inhibition of thyroid hormone secretion by an effect on proteolysis of active hormone from the colloid (lithium or an excess of iodide). Another large group of goitrogenic chemicals disrupts thyroid hormone economy by increasing the peripheral metabolism of thyroid hormones through an induction of hepatic microsomal enzymes. This group includes CNS-acting drugs (phenobarbital, benzodiazepines), calcium channel blockers (nicardipine, nifedipine), steroids (spironolactone), retinoids, chlorinated hydrocarbons (chlordane, DDT, TCDD), polyhalogenated biphenyls (PCB, PBB), and enzyme inducers. Thyroid hormone economy also can be disrupted by xenobiotics that inhibit the 5'monodeiodinase, which converts T4 in peripheral sites (e.g., liver and kidney) to biologically active T3. Inhibition of this enzyme by FD&C Red No. 3, amiodarone, and iopanoic acid lowers circulating T3 levels, which results in a compensatory increased secretion of thyroid-stimulating hormone (TSH), follicular cell hypertrophy and hyperplasia, and an increased incidence of follicular cell tumors in 2-year or lifetime studies in rats. Physiologic perturbations alone such as the feeding of an iodine-deficient diet, partial thyroidectomy, natural goitrogens in certain foods, and transplantation of TSH-secreting pituitary tumors in rodents also can disrupt thyroid hormone economy and, if sustained, increase the development of thyroid tumors in rats. A consistent finding with all of these goitrogens, be they either physiologic perturbations or xenobiotic chemicals, is the chronic hypersecretion of TSH, which by receptor-mediated events places the rodent thyroid gland at greater risk of developing tumors through a secondary mechanism of thyroid oncogenesis.

PMID: 7526405 [PubMed - indexed for MEDLINE]

Translation into English: Great if you want to have a thyroid disease!!!

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