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Wrinkles
Published in Charles Theisler, Adjuvant Medical Care, 2023
Retinol: The only FDA-approved topical treatment for wrinkles is tretinoin, known commercially as Retin-A and available by prescription. Retinol is a natural form of vitamin A and in high concentrations may be as effective as Retin-A without the side effects.3
The science of ageing
Published in Michael Parker, Charlie James, Fundamentals for Cosmetic Practice, 2022
Anti-ageing serums usually contain antioxidants, cell regulators or a combination of the two. Frequently used antioxidants include vitamins (such as those discussed previously), polyphenols and flavonoids and function by preventing damage caused by reactive oxygen species to cells and collagen fibres. Cell regulators, however, function by having direct effects on collagen metabolism and production and include retinols, peptides and growth factors. Retinol is the most frequently used cell regulator in anti-ageing preparations, and it has been demonstrated to aid in both intrinsic and extrinsic skin ageing by inducing collagen production as well as decreasing the expression of matrix metalloproteinases such as MMP-1. Oligo- and polypeptides included in anti-ageing creams can be designed to imitate amino acid sequences of important cutaneous molecules such as collagen or elastin. If applied topically, these peptides can induce the upregulation of the production of collagen and elastin, subsequently increasing their concentration within the skin and adding more volume and elasticity.
Psoriasis and lichen planus
Published in Rashmi Sarkar, Anupam Das, Sumit Sethi, Concise Dermatology, 2021
Retinoids are analogues of retinol (vitamin A). They exert important actions on cell division and maturation, and acitretin is of particular value in psoriasis. The drug benefits patients with all types of severe psoriasis after 3–4 weeks of administration but is most effective when used in combination with some form of ultraviolet treatment. Its major drawback is that it is markedly teratogenic and can only be given to fertile women if they use contraception and are prepared to continue using efficient and reliable contraceptive measures for 3 years after stopping treatment. Other significant toxicities include hyperlipidaemia and a possibility of hyperostosis and extraosseous calcification. In addition, it does have some hepatotoxicity in a few patients. These ‘significant’ toxicities are not common; but minor mucosal side effects occur in all patients, including drying of the lips and the buccal, nasal, and conjunctival mucosae. Minor generalized pruritus and slight hair loss also occur. Oral retinoids should only be prescribed by dermatologists, i.e. those who are familiar with their actions and effects.
A contemporary review of electronic waste through the lens of inhalation toxicology
Published in Inhalation Toxicology, 2021
Oyemwenosa N. Avenbuan, Gabriella Y. Meltzer, Christina Awada, Amna Raja, Andrij Holian, Judith T. Zelikoff
In vivo animal studies have shown that exposure to certain PCBs at high concentrations produce adverse neurodevelopmental, immunological, endocrine, and reproductive effects, as well as cancer in some cases (Wang et al. 2019). In a study by Brown et al. (2007), male and female Sprague-Dawley rats exposed via the diet to PCB Aroclor concentrations ranging from 25 to 200 ppm for 24 months, demonstrated sex-/Aroclor-dependent increases in hepatic tumors compared to controls. The hepato-tumorigenesis was associated with tissue accumulations of PCBs and dioxin equivalents and increased expression of cell proliferation and proliferating cell nuclear antigen (Brown et al. 2007). PCBs can also act as endocrine-disrupting chemicals (EDCs). In one study, four weekly 50 mg/kg doses of non-coplanar PCB153 were administered to C57BL/6 male mice. These exposures resulted in a significant decrease in plasma and liver tissue concentrations of retinyl esters, retinol, and all-trans-retinoic acid (atRA). This study suggests that disruption of retinoid homeostasis is caused by PCB153-induced activation of the constitutive androstane receptor (CAR), which adds to the obesogenic properties of PCBs (Shmarakov et al. 2019).
All-trans retinoic acid in anticancer therapy: how nanotechnology can enhance its efficacy and resolve its drawbacks
Published in Expert Opinion on Drug Delivery, 2021
Gabriel Silva Marques Borges, Flávia Alves Lima, Guilherme Carneiro, Gisele Assis Castro Goulart, Lucas Antônio Miranda Ferreira
Retinoids are synthetic or natural derivatives of vitamin A, including retinol, retinal, 13-cis retinoic acid (isotretinoin), and adapalene. All-trans retinoic acid (ATRA, tretinoin) is the physiological active form of vitamin A and is one of the most studied retinoids during the last 50 years. ATRA started to be used in 1971 as an anti-acne drug, showing a strong activity against skin disorders [1]. Beyond its dermatological use, in 1980, it was discovered that ATRA has important differentiation properties in hematological cells. This differentiation activity dramatically changed the course of acute promyelocytic leukemia (APL) [2]. The use of ATRA as an oral differentiation agent in APL patients was, back then, a unique case in antineoplastic therapy and turned APL from one of the most aggressive types of leukemia to one of the most successfully treatable [3].
Assessment of dermal safety of oil extracted from Periplaneta americana: acute dermal toxicity, irritation, and sensitization
Published in Cutaneous and Ocular Toxicology, 2020
Xian Li, Zhao He, Wei Feng Ding, Xin Zhang, Chen Jing Ma, Ying Feng
Previous research on the composition and antioxidant activity of P. americana oil has shown that the antioxidant activity of the oil is attributable to multiple active components such as oleic acid, linoleic acid, and vitamins A and E. Linoleic acid, which is the fatty acid showing the highest concentrations in P. americana oil, is an essential polyunsaturated fatty acid in the human body and can inhibit the production of lipid peroxides in the blood, liver, and brain38. Vitamin A, also known as retinol, alleviates photoaging of the skin and exerts anti-wrinkle effects. It is also a fat-soluble vitamin that can promote the differentiation of epithelial tissue, such as the skin and mucosa. At low concentrations, vitamin A can exert an inhibitory effect on the lipid peroxidation chain reaction39. Vitamin E can form stable oxidation products with free radicals and block the chain reaction of free radicals, resulting in its antioxidant effects40. Vitamin K can act as an electron carrier and participate in oxidation-reduction reactions and clear free radicals in vivo. Skin aging has been reported to be closely related to free radicals and enhancing the antioxidant capacity of the skin can help delay skin aging41. Therefore, P. americana oil has a wide application potential in the development of antioxidant products for external use.