Proclivity to develop irritant reactions and transcutaneous penetration of nicotinates has been investigated in 20 subjects of both sexes, divided into reactors and nonreactors on the basis of the responses to irritant stimuli. 1% sodium lauryl sulphate (patch application for 24 h) and 5% lactic acid in aqueous solutions were used to detect chemical and sensory (subjective) irritation. The vasodilatation induced was measured using a chromameter for 1 h after topical application of the chemical. The area-under-the-curve response and the peak response was used to assess the in vivo penetration of methyl nicotinate (10 mM in aqueous solution). Significant differences were found between reactors and non-reactors. Non-reactors showed a significantly decreased area-under-the-curve response and peak response to methyl nicotinate compared to reactors. Nicotinate-induced vasodilatation has been used as a model to study transcutaneous penetration of chemicals; the correlation between increased penetration of nicotinates and skin hyperreactivity to irritant substances may suggest an increased transcutaneous penetration of water-soluble chemicals in individuals with sensitive skin.
Cutaneous changes induced by aging can be quantified and monitored noninvasively by means of bioengineering tools. Skin elasticity, hydration, skin blood flow and skin surface pattern show age-related changes reflecting the damage of cutaneous structures involved. Impairment and degeneration of elastic and collagen networks are responsible for the progressive decrease in skin elasticity recorded during aging. Reduction in blood flow and water supply with probably defective stratum corneum binding result in reduced stratum corneum water content and transepidermal water loss. Morphological changes such as increased skin roughness pigmentation and alteration of skin surface pattern appearing from the age of 30 years onwards may be investigated at a subclinical level allowing the detection of early signs of aging.
Topical tretinoin has been reported as having anti-aging effects on photodamaged skin. The purpose of this study was to evaluate tretinoin-induced changes in the mechanical properties of the skin of 18 patients (aged 39 +/- 8 years) after 4 months of treatment with topical 0.05% tretinoin on one forearm and a placebo base cream on the other. The biomechanical skin parameters investigated were elasticity, extensibility and hysteresis and data were normalized for skin thickness. A slight but non-significant increase of skin elasticity was detected in the tretinoin-treated sites using low-stressing forces (1.2 X 10(4) Nm-2) and at higher loads (3.8 X 10(4) Nm-2), the increase in skin elasticity was significant (P less than 0.01). This improved skin elasticity was dependent on the increased collagen resulting from topical tretinoin and the replacement of elastotic material. However, topical tretinoin treatment did not improve the responses mediated by elastic fibres.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.