In this study, the effect of one cycle of winter to summer seasonal transition on the mechanical and physical properties of skin was investigated in vivo. Fourteen healthy skin volunteers aged ...between 22 and 42 years were studied at the volar lower and upper arms. The findings indicate a 22.15% and 34.29% decrease in trans-epidermal water loss (TEWL) and the average epidermal roughness (AER), respectively. Also, improved skin properties were observed such as a 25.48% rise in average epidermal hydration (AEH), 22.59% in skin thickness, 38.64% and 21.92% in melanin and redness, respectively, as well as an 8.25% rise in its firmness and 23.14% in elasticity when strained with uniaxial deformations. An inverse correlation was established between TEWL and AEH with a linear relationship between stratum corneum roughness versus TEWL as well as thickness and hydration. Also, the skin firmness exhibited a direct proportionality with TEWL and an inverse correlation with skin hydration where these relationships were stronger in summer than in winter. Furthermore, time-dependent results demonstrated three-staged elastic, viscoelastic and creep deformations with high, moderate and low strain rates respectively at both anatomical locations. The winter season displayed lower skin firmness and elasticity of 0.37 mm and 0.04 mm compared to 0.40 mm and 0.06 mm in summer accordingly. Anatomically, the two arm regions displayed different results with the upper arm having more consistent results than the lower arm. These results will find relevance in sensor skins and exoskeletons in Medicare, robotic and military technologies as well as innovations in cosmetics and dermatology.
Atopic dermatitis (AD) is a common chronic skin disease characterized by recurrent skin inflammation and a weak skin barrier, and is known to be a precursor to other allergic diseases such as asthma. ...AD affects up to 25% of children worldwide and the incidence continues to rise. There is still uncertainty about the optimal treatment strategy in terms of choice of treatment, potency, duration and frequency. This study aims to develop a computational method to design optimal treatment strategies for the clinically recommended 'proactive therapy' for AD. Proactive therapy aims to prevent recurrent flares once the disease has been brought under initial control. Typically, this is done by using an anti-inflammatory treatment such as a potent topical corticosteroid intensively for a few weeks to 'get control', followed by intermittent weekly treatment to suppress subclinical inflammation to 'keep control'. Using a hybrid mathematical model of AD pathogenesis that we recently proposed, we computationally derived the optimal treatment strategies for individual virtual patient cohorts, by recursively solving optimal control problems using a differential evolution algorithm. Our simulation results suggest that such an approach can inform the design of optimal individualized treatment schedules that include application of topical corticosteroids and emollients, based on the disease status of patients observed on their weekly hospital visits. We demonstrate the potential and the gaps of our approach to be applied to clinical settings.
This article is part of the themed issue 'Mathematical methods in medicine: neuroscience, cardiology and pathology'.
The deficit in cerebral blood flow (CBF) seen in patients with hypertension-induced vascular dementia is increasingly viewed as a therapeutic target for disease-modifying therapy. Progress is ...limited, however, due to uncertainty surrounding the mechanisms through which elevated blood pressure reduces CBF. To investigate this, we used the BPH/2 mouse, a polygenic model of hypertension. At 8 mo of age, hypertensive mice exhibited reduced CBF and cognitive impairment, mimicking the human presentation of vascular dementia. Small cerebral resistance arteries that run across the surface of the brain (pial arteries) showed enhanced pressure-induced constriction due to diminished activity of large-conductance Ca
-activated K
(BK) channels-key vasodilatory ion channels of cerebral vascular smooth muscle cells. Activation of BK channels by transient intracellular Ca
signals from the sarcoplasmic reticulum (SR), termed Ca
sparks, leads to hyperpolarization and vasodilation. Combining patch-clamp electrophysiology, high-speed confocal imaging, and proximity ligation assays, we demonstrated that this vasodilatory mechanism is uncoupled in hypertensive mice, an effect attributable to physical separation of the plasma membrane from the SR rather than altered properties of BK channels or Ca
sparks, which remained intact. This pathogenic mechanism is responsible for the observed increase in constriction and can now be targeted as a possible avenue for restoring healthy CBF in vascular dementia.
Introduction
The replenishment of skin lipids depleted in the dry skin state is a desirable therapeutic target to restore skin moisturization; however, there is limited evidence demonstrating the ...success of this approach through the use of topical emollients. The purpose of this study was to provide evidence of the benefits of a cream and equivalent lotion containing skin lipids in a multi-vesicular emulsion for the management of dry skin. The hypothesis was that the test cream and test lotion could sustain skin moisturization for longer than traditional emollients by sustainably delivering skin lipids.
Methods
A double-blind intra-subject vehicle-controlled single open-application test on the lower legs in people with dry, atopic dermatitis (atopic eczema)-prone, skin was conducted. There were six treatment sites, three per lower leg in each participant, which were treated with the test cream, the test lotion, three reference creams commonly prescribed in the UK and no treatment as a control. After baseline measurements of skin hydration, 100 μl of the test/reference creams was applied to each of the relevant treatment sites (random site allocation). Following treatment, measurements of skin hydration and scoring of visual dryness was conducted at timed intervals (3, 6, 12 and 24 h post-product application).
Results
The test cream and lotion both significantly increased skin hydration and reduced skin dryness for at least 24 h following a single application compared to a no treatment control site. Compared to three reference emollient creams the test cream and test lotion were the only products capable of sustaining clinically meaningful improvements in skin moisturization for 24 h.
Conclusion
The sustained moisturization imparted by the test products reduces the need for frequent emollient application, often requiring 3–4 applications per day for traditional emollients, and should reduce the high burden of managing dry skin conditions like atopic dermatitis.
pH in Atopic Dermatitis Danby, Simon G; Cork, Michael J
Current problems in dermatology,
2018, Letnik:
54
Journal Article
Recenzirano
Atopic dermatitis (synonym atopic eczema, AD) is a chronic inflammatory skin disorder essentially characterised by a red "itchy" skin rash. The condition is prevalent around the world, affecting ...15-30% of children and 2-10% of adults Odhiambo et al.: J Allergy Clin Immunol 2009;124:1251-1258.e23. The pathophysiological mechanisms underpinning AD are complex, broadly involving skin barrier dysfunction, an altered immune response (affecting both the adaptive and innate immune systems) and an unfavourable environment (external stressors) Werfel et al.: J Allergy Clin Immunol 2016;138:336-349. Intriguingly at the centre of this maelstrom of events, linking them together, is a very basic skin property - skin pH. Skin pH is a central regulator of skin barrier homeostasis and an important innate defence mechanism. Moreover, recent evidence suggests that elevated pH can also drive altered immune responses placing it squarely in the centre of AD pathogenesis, but just how important is skin pH to the development of AD? In this chapter, the current evidence entangling skin pH in AD pathogenesis is reviewed.
Summary
Background
Hidradenitis suppurativa (HS), also referred to as acne inversa, is a debilitating skin disease characterized by inflammatory nodules, chronic abscesses and tunnels (fistulae and ...sinuses). The association with pilonidal sinus disease (PSD) is frequently reported but not well documented.
Objectives
To determine the prevalence and characteristics of inflammatory skin lesions located in the intergluteal fold (IGF) of patients with HS.
Methods
This was an international multicentre retrospective cross‐sectional study based on data collection from a large cohort of patients with HS with and without histopathology.
Results From a total of 2465 patients with HS included in the study, 661 (27%) reported lesions in the IGF. These patients were significantly more often smokers and had more severe HS. Of the 238 patients with an available clinical diagnosis, intergluteal‐HS (IG‐HS) was diagnosed in 52 patients (22%) and PSD was diagnosed in 186 patients (78%). IG‐HS was associated with the localization of HS in the proximity of the IGF, including the buttocks, genitals and the anus. There was a possibility of misclassification bias in this study as a clinical/image‐based diagnosis or histopathology of the IGF lesions was not always available.
Conclusions
The high prevalence of PSD suggests a strong link between both entities. Therefore, it may be useful to identify common pathophysiological mechanisms and develop common therapeutic strategies.
What's already known about this topic?
The occurrence of pilonidal sinus disease has not been clearly reported among patients with hidradenitis suppurativa/acne inversa.
What does this study add?
This is the first study that investigated the prevalence of pilonidal sinus disease among a large cohort of patients and identified the patient characteristics.
Risk factors that might help to improve the management of patients were identified.
Respond to this article
Linked Comment: Frew and Navrazhina. Br J Dermatol 2019; 181:1121.
Targeting Skin Barrier Function in Atopic Dermatitis van den Bogaard, Ellen H; Elias, Peter M; Goleva, Elena ...
The journal of allergy and clinical immunology in practice (Cambridge, MA),
05/2023, Letnik:
11, Številka:
5
Journal Article
Recenzirano
Atopic dermatitis (AD) is the most common chronic inflammatory skin disease in the general population. Skin barrier dysfunction is the central abnormality leading to AD. The cause of skin barrier ...dysfunction is complex and rooted in genetic mutations, interactions between the immune pathway activation and epithelial cells, altered host defense mechanisms, as well as environmental influences that cause epithelial cell activation and release of alarmins (such as thymic stromal lymphopoietin) that can activate the type 2 immune pathway, including generation of interleukins 4 and 13, which induces defects in the skin barrier and increased allergic inflammation. These inflammatory pathways are further influenced by environmental factors including the microbiome (especially Staphylococcus aureus), air pollution, stress, and other factors. As such, AD is a syndrome involving multiple phenotypes, all of which have in common skin barrier dysfunction as a key contributing factor. Understanding mechanisms leading to skin barrier dysfunction in AD is pointing to the development of new topical and systemic treatments in AD that helps keep skin borders secure and effectively treat the disease.
The muon anomalous magnetic moment measurement, when compared with theory, can be used to test many extensions to the standard model. The most recent measurement made by the Brookhaven E821 ...Collaboration reduces the uncertainty on the world average of
a
μ
to 0.7 ppm, comparable in precision to theory. This paper describes the experiment and the current theoretical efforts to establish a correct standard model reference value for the muon anomaly.
Skin physiology is dynamically changing over the first years of postnatal life; however, ethnic variations are still unclear. The aim of this study was to characterize infant skin barrier function, ...epidermal structure, and desquamation-related enzymatic activity as compared to that of adult skin in an East Asian population. The skin properties of 52 infants (3-24 months) and 27 adults (20-40 years) were assessed by noninvasive methods at the dorsal forearm and upper inner arm. Transepidermal water loss and skin surface conductance values were higher and more dispersed for infants compared to adults. Infant skin surface pH was slightly lower than adult on the dorsal forearm. The infant SC and viable epidermis were thinner compared to adults with differences that were site-specific. Although the chymotrypsin-like activity for infant skin was comparable to adult level, the caseinolytic specific activity was significantly higher for the infant cohort. These observations indicate a differently controlled pattern of corneocyte desquamation in infants. In conclusion, structural and functional differences exist between infant and adult skin in the East Asian population pointing to dynamic maturation of the epidermal barrier early in life.
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