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Blount H, Valenza A, Ward J, Caggiari S, Worsley PR, Filingeri D. The effect of female breast surface area on skin stiffness and tactile sensitivity at rest and following exercise in the heat. Exp Physiol 2024. [PMID: 39173060 DOI: 10.1113/ep091990] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2024] [Accepted: 07/29/2024] [Indexed: 08/24/2024]
Abstract
Female development includes significant morphological changes across the breast. Yet, whether differences in breast surface area (BrSA) modify breast skin stiffness and tactile sensitivity at rest and after exercise in the heat remain unclear. We investigated the relationship between BrSA and skin stiffness and tactile sensitivity in 20 young to middle-aged women (27 ± 8 years of age) of varying breast sizes (BrSA range: 147-502 cm2) at rest and after a submaximal run in a warm climatic chamber (32 C ${\mathrm{C}}$ ± 0 . 6 C ; ${\mathrm{0}}{\mathrm{.6C;}}$ 53% ± 1.7% relative humidity). Skin stiffness above and below the nipple and tactile sensitivity from the nipple down were measured. Associations between BrSA and both skin stiffness and tactile sensitivity at rest were determined via correlation analyses. Effects of exercise and test site were assessed by a two-way ANOVA. Skin stiffness was positively correlated with BrSA 3 cm above the areola edge (r = 0.61, P = 0.005) and at the superior areola border (r = 0.54, P = 0.016), but not below the nipple (P > 0.05). The area 3 cm below the areola was also significantly stiffer than all other test sites (P < 0.043). Tactile sensitivity did not vary with BrSA (P > 0.09), but it varied across the breast (i.e., the area 3 cm below the areola was more sensitive than the inferior areola edge; P = 0.018). Skin stiffness and tactile sensitivity across the breast decreased after exercise by ∼37% (P < 0.001) and ∼45% (P = 0.008), respectively. These findings expand our fundamental understanding of the mechanosensory properties of the female breast, and they could help to inform sportswear innovation to better meet the support needs of women of different breast sizes at rest and following exercise.
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Affiliation(s)
- Hannah Blount
- ThermosenseLab, Skin Sensing Research Group, School of Health Sciences, The University of Southampton, Southampton, UK
| | - Alessandro Valenza
- ThermosenseLab, Skin Sensing Research Group, School of Health Sciences, The University of Southampton, Southampton, UK
- Sport and Exercise Sciences Research Unit, SPPEFF Department, University of Palermo, Palermo, Italy
| | - Jade Ward
- ThermosenseLab, Skin Sensing Research Group, School of Health Sciences, The University of Southampton, Southampton, UK
| | - Silvia Caggiari
- PressureLab, Skin Sensing Research Group, School of Health Sciences, The University of Southampton, Southampton, UK
| | - Peter R Worsley
- PressureLab, Skin Sensing Research Group, School of Health Sciences, The University of Southampton, Southampton, UK
| | - Davide Filingeri
- ThermosenseLab, Skin Sensing Research Group, School of Health Sciences, The University of Southampton, Southampton, UK
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2
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Han KS, Sander IB, Kumer J, Resnick E, Booth C, Cheng G, Im Y, Starich B, Kiemen AL, Phillip JM, Reddy S, Joshu CE, Sunshine JC, Walston JD, Wirtz D, Wu PH. qMAP enabled microanatomical mapping of human skin aging. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.03.588011. [PMID: 39005293 PMCID: PMC11244916 DOI: 10.1101/2024.04.03.588011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/16/2024]
Abstract
Aging is a major driver of diseases in humans. Identifying features associated with aging is essential for designing robust intervention strategies and discovering novel biomarkers of aging. Extensive studies at both the molecular and organ/whole-body physiological scales have helped determined features associated with aging. However, the lack of meso-scale studies, particularly at the tissue level, limits the ability to translate findings made at molecular scale to impaired tissue functions associated with aging. In this work, we established a tissue image analysis workflow - quantitative micro-anatomical phenotyping (qMAP) - that leverages deep learning and machine vision to fully label tissue and cellular compartments in tissue sections. The fully mapped tissue images address the challenges of finding an interpretable feature set to quantitatively profile age-related microanatomic changes. We optimized qMAP for skin tissues and applied it to a cohort of 99 donors aged 14 to 92. We extracted 914 microanatomic features and found that a broad spectrum of these features, represented by 10 cores processes, are strongly associated with aging. Our analysis shows that microanatomical features of the skin can predict aging with a mean absolute error (MAE) of 7.7 years, comparable to state-of-the-art epigenetic clocks. Our study demonstrates that tissue-level architectural changes are strongly associated with aging and represent a novel category of aging biomarkers that complement molecular markers. Our results highlight the complex and underexplored multi-scale relationship between molecular and tissue microanatomic scales.
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Affiliation(s)
- Kyu Sang Han
- Department of Chemical & Biomolecular Engineering, Johns Hopkins University, Baltimore, MD
- The Johns Hopkins Institute for NanoBioTechnology, Johns Hopkins University, Baltimore, MD
| | - Inbal B Sander
- Department of Dermatology, Johns Hopkins University, Baltimore, MD
| | - Jacqueline Kumer
- Department of Illustration Practice, Maryland Institute College of Art, Baltimore, MD
| | - Eric Resnick
- Department of Medicine, University of Maryland School of Medicine, Baltimore, MD
| | - Clare Booth
- Center for Cancer Research, National Cancer Institute, Frederick, MD
| | - Guoqing Cheng
- Department of Chemical & Biomolecular Engineering, Johns Hopkins University, Baltimore, MD
- The Johns Hopkins Institute for NanoBioTechnology, Johns Hopkins University, Baltimore, MD
| | - Yebin Im
- Department of Chemical & Biomolecular Engineering, Johns Hopkins University, Baltimore, MD
- The Johns Hopkins Institute for NanoBioTechnology, Johns Hopkins University, Baltimore, MD
| | - Bartholomew Starich
- Department of Chemical & Biomolecular Engineering, Johns Hopkins University, Baltimore, MD
- The Johns Hopkins Institute for NanoBioTechnology, Johns Hopkins University, Baltimore, MD
| | - Ashley L Kiemen
- Department of Pathology, Johns Hopkins School of Medicine, Baltimore, MD
| | - Jude M Phillip
- Department of Chemical & Biomolecular Engineering, Johns Hopkins University, Baltimore, MD
- The Johns Hopkins Institute for NanoBioTechnology, Johns Hopkins University, Baltimore, MD
- Department of Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, MD
- Department of Oncology, Johns Hopkins School of Medicine, Baltimore, MD
| | - Sashank Reddy
- The Johns Hopkins Institute for NanoBioTechnology, Johns Hopkins University, Baltimore, MD
- Department of Plastic and Reconstructive Surgery, Johns Hopkins School of Medicine, Baltimore, MD
| | - Corrine E Joshu
- Department of Epidemiology, Johns Hopkins School of Public Health, Baltimore, MD
| | - Joel C Sunshine
- Department of Dermatology, Johns Hopkins University, Baltimore, MD
| | - Jeremy D Walston
- Department of Medicine, Division of Geriatrics and Gerontology, Johns Hopkins School of Medicine, Baltimore, MD
| | - Denis Wirtz
- Department of Chemical & Biomolecular Engineering, Johns Hopkins University, Baltimore, MD
- The Johns Hopkins Institute for NanoBioTechnology, Johns Hopkins University, Baltimore, MD
- Department of Oncology, Johns Hopkins School of Medicine, Baltimore, MD
| | - Pei-Hsun Wu
- Department of Chemical & Biomolecular Engineering, Johns Hopkins University, Baltimore, MD
- The Johns Hopkins Institute for NanoBioTechnology, Johns Hopkins University, Baltimore, MD
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3
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Cho H, Dohi T, Wakai H, Quong WL, Linh NDT, Usami S, Ogawa R. In the face and neck, keloid scar distribution is related to skin thickness and stiffness changes associated with movement. Wound Repair Regen 2024; 32:419-428. [PMID: 38602106 DOI: 10.1111/wrr.13180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Revised: 02/25/2024] [Accepted: 04/01/2024] [Indexed: 04/12/2024]
Abstract
Keloid scars tend to occur in high-tension sites due to mechanical stimuli that are involved in their development. To date, a detailed analysis of keloid distribution focused specifically on facial and neck areas has not been reported, and limited literature exists as to the related mechanical factors. To rectify this deficiency of knowledge, we first quantified the facial and neck keloid distribution observed clinically in 113 patients. Subsequently, we performed a rigorous investigation into the mechanical factors and their associated changes at these anatomic sites in healthy volunteers without a history of pathologic scarring. The association between keloid-predilection sites and sebaceous gland-dense and acne-prone sites was also examined. To assess skin stretch, thickness and stiffness, VECTRA, ultrasound and indentometer were utilised. Baseline skin stiffness and thickness were measured, as well as the magnitude of change in these values associated with facial expression and postural changes. Within the face and neck, keloids were most common near the mandibular angle (41.3%) and lateral submental (20.0%) regions. These areas of increased keloid incidence were not associated with areas more dense in sebaceous glands, nor linked consistently with acne-susceptible regions. Binomial logistic regression revealed that changes in skin stiffness and thickness related to postural changes significantly predicted keloid distribution. Skin stiffness and thickness changes related to prolonged mechanical forces (postural changes) are most pronounced at sites of high keloid predilection. This finding further elucidates the means by which skin stretch and tension are related to keloid development. As a more detailed analysis of mechanical forces on facial and neck skin, this study evaluates the nuances of multiple skin-mechanical properties, and their changes in a three-dimensional framework. Such factors may be critical to better understanding keloid progression and development in the face and neck.
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Affiliation(s)
- Hoyu Cho
- Department of Plastic, Reconstructive and Regenerative Surgery, Nippon Medical School, Tokyo, Japan
| | - Teruyuki Dohi
- Department of Plastic, Reconstructive and Regenerative Surgery, Nippon Medical School, Tokyo, Japan
| | - Hanae Wakai
- Department of Plastic, Reconstructive and Regenerative Surgery, Nippon Medical School, Tokyo, Japan
| | - Whitney Laurel Quong
- Department of Plastic, Reconstructive and Regenerative Surgery, Nippon Medical School, Tokyo, Japan
- Department of Plastic, Reconstructive, and Aesthetic Surgery, University of Toronto, Toronto, Ontario, Canada
| | - Nguyen Doan Tien Linh
- Department of Plastic, Reconstructive and Regenerative Surgery, Nippon Medical School, Tokyo, Japan
| | - Satoshi Usami
- Department of Plastic, Reconstructive and Regenerative Surgery, Nippon Medical School, Tokyo, Japan
- Graduate School of Education, The University of Tokyo, Tokyo, Japan
| | - Rei Ogawa
- Department of Plastic, Reconstructive and Regenerative Surgery, Nippon Medical School, Tokyo, Japan
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4
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Siquier-Dameto G, Boadas-Vaello P, Verdú E. Intradermal Treatment with a Hyaluronic Acid Complex Supplemented with Amino Acids and Antioxidant Vitamins Improves Cutaneous Hydration and Viscoelasticity in Healthy Subjects. Antioxidants (Basel) 2024; 13:770. [PMID: 39061838 PMCID: PMC11274003 DOI: 10.3390/antiox13070770] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2024] [Revised: 06/21/2024] [Accepted: 06/23/2024] [Indexed: 07/28/2024] Open
Abstract
Intradermal injection of bioactive compounds is used to reduce the effects of aging skin. The aim of this work is to study the response of facial injection of a hyaluronic acid complex supplemented with amino acids and antioxidant vitamins on skin rejuvenation. A total of 40 healthy adult subjects were recruited to whom this complex was injected into the facial skin, three consecutive times every two weeks. Together with assessing the degree of skin hydration, the level of skin microcirculation, wrinkles, skin color, and skin biomechanical parameters were evaluated. Using the GAIS scale, the degree of satisfaction of the participants was assessed. At 42 days (D42), there was an 11-12% increase in skin hydration and viscoelasticity, a 23% increase in skin density, a 27% increase in skin microcirculation, and a significant lightening and whitening of skin color, but without causing changes in skin wrinkles. A value between 1 and 3 on the GAIS scale was observed between 70 and 92% of the participants, and 87% of subjects found their skin more beautiful, 85% would recommend this treatment, and more than 50% found their face rejuvenated. In summary, the intradermal treatment tested suggests skin rejuvenation, with a good degree of safety.
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Affiliation(s)
- Gabriel Siquier-Dameto
- Dameto Clinics International, 1171 VC Badhoevedorp, The Netherlands;
- Research Group of Clinical Anatomy, Embryology and Neuroscience (NEOMA), Department of Medical Sciences, University of Girona, E-17003 Girona, Catalonia, Spain;
| | - Pere Boadas-Vaello
- Research Group of Clinical Anatomy, Embryology and Neuroscience (NEOMA), Department of Medical Sciences, University of Girona, E-17003 Girona, Catalonia, Spain;
| | - Enrique Verdú
- Research Group of Clinical Anatomy, Embryology and Neuroscience (NEOMA), Department of Medical Sciences, University of Girona, E-17003 Girona, Catalonia, Spain;
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5
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Duraes M, Briot N, Connesson N, Chagnon G, Payan Y, Duflos C, Rathat G, Captier G, Subsol G, Herlin C. Evaluation of breast skin and tissue stiffness using a non-invasive aspiration device and impact of clinical predictors. Clin Anat 2024; 37:329-336. [PMID: 38174585 DOI: 10.1002/ca.24134] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2023] [Revised: 12/01/2023] [Accepted: 12/21/2023] [Indexed: 01/05/2024]
Abstract
A personalized 3D breast model could present a real benefit for preoperative discussion with patients, surgical planning, and guidance. Breast tissue biomechanical properties have been poorly studied in vivo, although they are important for breast deformation simulation. The main objective of our study was to determine breast skin thickness and breast skin and adipose/fibroglandular tissue stiffness. The secondary objective was to assess clinical predictors of elasticity and thickness: age, smoking status, body mass index, contraception, pregnancies, breastfeeding, menopausal status, history of radiotherapy or breast surgery. Participants were included at the Montpellier University Breast Surgery Department from March to May 2022. Breast skin thickness was measured by ultrasonography, breast skin and adipose/fibroglandular tissue stiffnesses were determined with a VLASTIC non-invasive aspiration device at three different sites (breast segments I-III). Multivariable linear models were used to assess clinical predictors of elasticity and thickness. In this cohort of 196 women, the mean breast skin and adipose/fibroglandular tissue stiffness values were 39 and 3 kPa, respectively. The mean breast skin thickness was 1.83 mm. Only menopausal status was significantly correlated with breast skin thickness and adipose/fibroglandular tissue stiffness. The next step will be to implement these stiffness and thickness values in a biomechanical breast model and to evaluate its capacity to predict breast tissue deformations.
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Affiliation(s)
- Martha Duraes
- Department of Breast Surgery, Montpellier University Hospital, Montpellier, France
- Faculty of Medicine Montpellier-Nîmes, Laboratory of Anatomy of Montpellier, Montpellier University, Montpellier, France
- Research-Team ICAR, LIRMM, University of Montpellier, Montpellier, France
| | - Noemie Briot
- Univ. Grenoble Alpes, CNRS, UMR 5525, VetAgro Sup, Grenoble INP, TIMC, Grenoble, France
| | - Nathanael Connesson
- Univ. Grenoble Alpes, CNRS, UMR 5525, VetAgro Sup, Grenoble INP, TIMC, Grenoble, France
| | - Gregory Chagnon
- Univ. Grenoble Alpes, CNRS, UMR 5525, VetAgro Sup, Grenoble INP, TIMC, Grenoble, France
| | - Yohan Payan
- Univ. Grenoble Alpes, CNRS, UMR 5525, VetAgro Sup, Grenoble INP, TIMC, Grenoble, France
| | - Claire Duflos
- Department of Clinical Unit Epidemiology, Montpellier University Hospital, Montpellier, France
| | - Gauthier Rathat
- Department of Breast Surgery, Montpellier University Hospital, Montpellier, France
| | - Guillaume Captier
- Faculty of Medicine Montpellier-Nîmes, Laboratory of Anatomy of Montpellier, Montpellier University, Montpellier, France
- Research-Team ICAR, LIRMM, University of Montpellier, Montpellier, France
| | - Gerard Subsol
- Research-Team ICAR, LIRMM, University of Montpellier, Montpellier, France
| | - Christian Herlin
- Research-Team ICAR, LIRMM, University of Montpellier, Montpellier, France
- Department of Plastic Surgery, Montpellier University Hospital, Montpellier, France
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6
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Song G, Gosain AK, Buganza Tepole A, Rhee K, Lee T. Exploring uncertainty in hyper-viscoelastic properties of scalp skin through patient-specific finite element models for reconstructive surgery. Comput Methods Biomech Biomed Engin 2024:1-15. [PMID: 38339988 DOI: 10.1080/10255842.2024.2313067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Accepted: 01/10/2024] [Indexed: 02/12/2024]
Abstract
Understanding skin responses to external forces is crucial for post-cutaneous flap wound healing. However, the in vivo viscoelastic behavior of scalp skin remains poorly understood. Personalized virtual surgery simulations offer a way to study tissue responses in relevant 3D geometries. Yet, anticipating wound risk remains challenging due to limited data on skin viscoelasticity, which hinders our ability to determine the interplay between wound size and stress levels. To bridge this gap, we reexamine three clinical cases involving scalp reconstruction using patient-specific geometric models and employ uncertainty quantification through a Monte Carlo simulation approach to study the effect of skin viscoelasticity on the final stress levels from reconstructive surgery. Utilizing the generalized Maxwell model via the Prony series, we can parameterize and efficiently sample a realistic range of viscoelastic response and thus shed light on the influence of viscoelastic material uncertainty in surgical scenarios. Our analysis identifies regions at risk of wound complications based on reported threshold stress values from the literature and highlights the significance of focusing on long-term responses rather than short-term ones.
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Affiliation(s)
- Gyohyeon Song
- Department of Intelligent Robotics, Sungkyunkwan University, Suwon, 16419, Republic of Korea
| | - Arun K Gosain
- Surgery (Pediatric Surgery), Plastic Surgery, Lurie Children's Hospital of Chicago, Northwestern Feinberg School of Medicine, Chicago 60611, IL, United States
| | - Adrian Buganza Tepole
- Department of Mechanical Engineering, Purdue University, West Lafayette 47907, IN, United States
| | - Kyehan Rhee
- Department of Mechanical Engineering, Myongji University, Yongin, 17058, Republic of Korea
| | - Taeksang Lee
- Department of Mechanical Engineering, Myongji University, Yongin, 17058, Republic of Korea
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7
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Lin CY, Sugerman GP, Kakaletsis S, Meador WD, Buganza AT, Rausch MK. Sex- and age-dependent skin mechanics-A detailed look in mice. Acta Biomater 2024; 175:106-113. [PMID: 38042263 DOI: 10.1016/j.actbio.2023.11.032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Revised: 10/28/2023] [Accepted: 11/21/2023] [Indexed: 12/04/2023]
Abstract
Skin aging is of immense societal and, thus, scientific interest. Because mechanics play a critical role in skin's function, a plethora of studies have investigated age-induced changes in skin mechanics. Nonetheless, much remains to be learned about the mechanics of aging skin. This is especially true when considering sex as a biological variable. In our work, we set out to answer some of these questions using mice as a model system. Specifically, we combined mechanical testing, histology, collagen assays, and two-photon microscopy to identify age- and sex-dependent changes in skin mechanics and to relate them to structural, microstructural, and compositional factors. Our work revealed that skin stiffness, thickness, and collagen content all decreased with age and were sex dependent. Interestingly, sex differences in stiffness were age induced. We hope our findings not only further our fundamental understanding of skin aging but also highlight both age and sex as important variables when conducting studies on skin mechanics. STATEMENT OF SIGNIFICANCE: Our work addresses the question, "How do sex and age affect the mechanics of skin?" Answering this question is of both scientific and societal importance. We do so in mice as a model system. Thereby, we hope to add clarity to a body of literature that appears divided on the effect of both factors. Our findings have important implications for those studying age and sex differences, especially in mice as a model system.
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Affiliation(s)
- Chien-Yu Lin
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX, USA
| | - Gabriella P Sugerman
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX, USA
| | - Sotirios Kakaletsis
- Department of Aerospace Engineering & Engineering Mechanics, The University of Texas at Austin, Austin, TX, USA
| | - William D Meador
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX, USA
| | - Adrian T Buganza
- Department of Mechanical Engineering, Purdue University, West Lafayette, IN, USA
| | - Manuel K Rausch
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX, USA; Department of Aerospace Engineering & Engineering Mechanics, The University of Texas at Austin, Austin, TX, USA; Oden Institute for Computational Engineering & Sciences, The University of Texas at Austin, Austin, TX, USA.
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8
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Wang H, Duan C, Keate RL, Ameer GA. Panthenol Citrate Biomaterials Accelerate Wound Healing and Restore Tissue Integrity. Adv Healthc Mater 2023; 12:e2301683. [PMID: 37327023 DOI: 10.1002/adhm.202301683] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2023] [Indexed: 06/17/2023]
Abstract
Impaired wound healing is a common complication for diabetic patients and effective diabetic wound management remains a clinical challenge. Furthermore, a significant problem that contributes to patient morbidity is the suboptimal quality of healed skin, which often leads to reoccurring chronic skin wounds. Herein, a novel compound and biomaterial building block, panthenol citrate (PC), is developed. It has interesting fluorescence and absorbance properties, and it is shown that PC can be used in soluble form as a wash solution and as a hydrogel dressing to address impaired wound healing in diabetes. PC exhibits antioxidant, antibacterial, anti-inflammatory, and pro-angiogenic properties, and promotes keratinocyte and dermal fibroblast migration and proliferation. When applied in a splinted excisional wound diabetic rodent model, PC improves re-epithelialization, granulation tissue formation, and neovascularization. It also reduces inflammation and oxidative stress in the wound environment. Most importantly, it improves the regenerated tissue quality with enhanced mechanical strength and electrical properties. Therefore, PC could potentially improve wound care management for diabetic patients and play a beneficial role in other tissue regeneration applications.
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Affiliation(s)
- Huifeng Wang
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, 60208, USA
- Center for Advanced Regenerative Engineering, Northwestern University, Evanston, IL, 60208, USA
| | - Chongwen Duan
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, 60208, USA
- Center for Advanced Regenerative Engineering, Northwestern University, Evanston, IL, 60208, USA
| | - Rebecca L Keate
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, 60208, USA
- Center for Advanced Regenerative Engineering, Northwestern University, Evanston, IL, 60208, USA
| | - Guillermo A Ameer
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, 60208, USA
- Center for Advanced Regenerative Engineering, Northwestern University, Evanston, IL, 60208, USA
- Department of Surgery, Feinberg School of Medicine, Northwestern University, Chicago, IL, 60611, USA
- Chemistry of Life Processes Institute, Northwestern University, Evanston, IL, 60208, USA
- Simpson Querrey Institute, Northwestern University, Chicago, IL, 60611, USA
- International Institute for Nanotechnology, Northwestern University, Evanston, IL, 60208, USA
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9
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Dul M, Alali M, Ameri M, Burke MD, Craig CM, Creelman BP, Dick L, Donnelly RF, Eakins MN, Frivold C, Forster AH, Gilbert PA, Henke S, Henry S, Hunt D, Lewis H, Maibach HI, Mistilis JJ, Park JH, Prausnitz MR, Robinson DK, Hernandez CAR, Ross C, Shin J, Speaker TJ, Taylor KM, Zehrung D, Birchall JC, Jarrahian C, Coulman SA. Assessing the risk of a clinically significant infection from a Microneedle Array Patch (MAP) product. J Control Release 2023; 361:236-245. [PMID: 37437849 DOI: 10.1016/j.jconrel.2023.07.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Revised: 06/28/2023] [Accepted: 07/01/2023] [Indexed: 07/14/2023]
Abstract
Microneedle Array Patches (MAPs) are an emerging dosage form that creates transient micron-sized disruptions in the outermost physical skin barrier, the stratum corneum, to facilitate delivery of active pharmaceutical ingredients to the underlying tissue. Numerous MAP products are proposed and there is significant clinical potential in priority areas such as vaccination. However, since their inception scientists have hypothesized about the risk of a clinically significant MAP-induced infection. Safety data from two major Phase 3 clinical trials involving hundreds of participants, who in total received tens of thousands of MAP applications, does not identify any clinically significant infections. However, the incumbent data set is not extensive enough to make definitive generalizable conclusions. A comprehensive assessment of the infection risk is therefore advised for MAP products, and this should be informed by clinical and pre-clinical data, theoretical analysis and informed opinions. In this article, a group of key stakeholders identify some of the key product- and patient-specific factors that may contribute to the risk of infection from a MAP product and provide expert opinions in the context of guidance from regulatory authorities. Considerations that are particularly pertinent to the MAP dosage form include the specifications of the finished product (e.g. microbial specification), it's design features, the setting for administration, the skill of the administrator, the anatomical application site, the target population and the clinical context. These factors, and others discussed in this article, provide a platform for the development of MAP risk assessments and a stimulus for early and open dialogue between developers, regulatory authorities and other key stakeholders, to expedite and promote development of safe and effective MAP products.
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Affiliation(s)
- Maria Dul
- Cardiff School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Cardiff, UK
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Howard I Maibach
- Department of Dermatology, University of California San Francisco, San Francisco, CA, USA
| | | | - Jung-Hwan Park
- Department of Bionano Technology, Gachon University, Seongnam, Republic of Korea
| | - Mark R Prausnitz
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA, USA
| | | | | | | | | | | | - Kevin Michael Taylor
- University College London School of Pharmacy, British Pharmacopoeia Commission, UK
| | | | - James C Birchall
- Cardiff School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Cardiff, UK
| | | | - Sion A Coulman
- Cardiff School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Cardiff, UK.
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10
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Lin CY, Sugerman GP, Kakaletsis S, Meador WD, Buganza AT, Rausch MK. Sex- and Age-dependent Skin Mechanics - A Detailed Look in Mice. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.08.531781. [PMID: 36945509 PMCID: PMC10028869 DOI: 10.1101/2023.03.08.531781] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/12/2023]
Abstract
Skin aging is of immense societal and, thus, scientific interest. Because mechanics play a critical role in skin's function, a plethora of studies have investigated age-induced changes in skin mechanics. Nonetheless, much remains to be learned about the mechanics of aging skin. This is especially true when considering sex as a biological variable. In our work, we set out to answer some of these questions using mice as a model system. Specifically, we combined mechanical testing, histology, collagen assays, and two-photon microscopy to identify age- and sex-dependent changes in skin mechanics and to relate them to structural, microstructural, and compositional factors. Our work revealed that skin stiffness, thickness, and collagen content all decreased with age and were sex dependent. Interestingly, sex differences in stiffness were age induced. We hope our findings not only further our fundamental understanding of skin aging but also highlight both age and sex as important variables when conducting studies on skin mechanics.
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Affiliation(s)
- Chien-Yu Lin
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, Texas, USA
| | - Gabriella P Sugerman
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, Texas, USA
| | - Sotirios Kakaletsis
- Department of Aerospace Engineering & Engineering Mechanics, The University of Texas at Austin, Austin, Texas, USA
| | - William D Meador
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, Texas, USA
| | - Adrian T Buganza
- Department of Mechanical Engineering, Purdue University, West Lafayette, Indiana, USA
| | - Manuel K Rausch
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, Texas, USA
- Department of Aerospace Engineering & Engineering Mechanics, The University of Texas at Austin, Austin, Texas, USA
- Oden Institute for Computational Engineering & Sciences, The University of Texas at Austin, Austin, Texas, USA
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11
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Grześkowiak M, Kocur P, Łochyński D. Relationship between morphometric and mechanical properties of superficial lumbosacral soft tissue layers in healthy young adults. Front Physiol 2023; 14:1175035. [PMID: 37260591 PMCID: PMC10228649 DOI: 10.3389/fphys.2023.1175035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Accepted: 04/17/2023] [Indexed: 06/02/2023] Open
Abstract
Introduction: It is commonly considered that myotonometry is a non-invasive method capable of quantifying linear elastic and viscoelastic properties of the myofascial tissue through the application of a weak mechanical impulse to the surface of the skin. However, before the impulse can reach the myofascial tissue, it must cross more superficial tissues such as the skin and subcutaneous tissue (ST). All these superficial tissues have different distributions and organizations of structural components. Therefore, the study aimed to examine the potential relationships between the mechanical and morphometric properties of various superficial soft tissues surrounding the lumbar multifidus muscle (LM). Methods: Myotonometric measurements of dynamic stiffness, logarithmic decrement, and creep, and ultrasonographic measurements of thickness and echogenicity of cutaneous, subcutaneous, perimuscular tissue, and LM were obtained from 50 healthy individuals in the resting prone position and during contralateral arm lift. Results: The most important findings were that in both the relaxed and contracted LM state, the dynamic stiffness strongly negatively (r = -0.69; p < 0.001 in relaxation, r = -0.83; p < 0.001 in contraction) and creep strongly positively (r = 0.79; p < 0.001 in relaxation, r = 0.85; p < 0.001 in contraction) correlated with the thicknesses of the ST. Similar but weaker correlations were noticed between both these measures and the perimuscular tissue thickness. Elasticity was uncorrelated to the thicknesses of the tissues. With LM contraction (change from the relaxed to contracted state), the relative increase in dynamic stiffness was correlated with the relative decrease in dermis (r = -0.51; p < 0.001) and ST (r = -0.47; p = 0.001) thickness, and with the relative increase in LM (r = 0.36; p = 0.010) thickness. Moreover, the relative decrease (thinning) in the ST thickness was correlated with the relative increase in logarithmic decrement (i.e., decrease in soft tissue elasticity, r = -0.37, p = 0.011). The mechanical properties of the soft tissues were not related to their echogenicity. Discussion: In conclusion, the thicker the subcutaneous and perimuscular layers, the lesser the stiffness and the greater the time-dependent deformation to the external force of the tissues surrounding the LM during its relaxation and isometric contraction. Moreover, the greater the thinning of the ST and the thickening of the LM during its contraction, the higher the increase in lumbosacral tissue stiffness and the decrease in elasticity. Therefore, one should consider the thickness of the ST before planning or analyzing the outcomes of myotonometric or other external biomechanical measurements to avoid drawing the wrong conclusions about the mechanical properties of the myofascial tissue.
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Affiliation(s)
- Marcin Grześkowiak
- Department of Cardiological and Rheumatological Rehabilitation, Poznan University of Physical Education, Poznan, Poland
| | - Piotr Kocur
- Department of Musculoskeletal Physiotherapy, Poznan University of Physical Education, Poznan, Poland
| | - Dawid Łochyński
- Department of Neuromuscular Physiotherapy, Poznan University of Physical Education, Poznan, Poland
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12
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Beatty MW, Wee AG, Marx DB, Ridgway L, Simetich B, De Sousa TC, Vakilzadian K, Schulte J. Viscoelastic Properties of Human Facial Skin and Comparisons with Facial Prosthetic Elastomers. MATERIALS (BASEL, SWITZERLAND) 2023; 16:2023. [PMID: 36903138 PMCID: PMC10004410 DOI: 10.3390/ma16052023] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 02/23/2023] [Accepted: 02/23/2023] [Indexed: 06/18/2023]
Abstract
Prosthesis discomfort and a lack of skin-like quality is a source of patient dissatisfaction with facial prostheses. To engineer skin-like replacements, knowledge of the differences between facial skin properties and those for prosthetic materials is essential. This project measured six viscoelastic properties (percent laxity, stiffness, elastic deformation, creep, absorbed energy, and percent elasticity) at six facial locations with a suction device in a human adult population equally stratified for age, sex, and race. The same properties were measured for eight facial prosthetic elastomers currently available for clinical usage. The results showed that the prosthetic materials were 1.8 to 6.4 times higher in stiffness, 2 to 4 times lower in absorbed energy, and 2.75 to 9 times lower in viscous creep than facial skin (p < 0.001). Clustering analyses determined that facial skin properties fell into three groups-those associated with body of ear, cheek, and remaining locations. This provides baseline information for designing future replacements for missing facial tissues.
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Affiliation(s)
- Mark W. Beatty
- Research Service, VA Nebraska-Western Iowa Healthcare System, 4101 Woolworth Avenue, Omaha, NE 68105, USA
- Department of Adult Restorative Dentistry, University of Nebraska Medical Center College of Dentistry, 4000 East Campus Loop South, Lincoln, NE 68583, USA
| | - Alvin G. Wee
- Research Service, VA Nebraska-Western Iowa Healthcare System, 4101 Woolworth Avenue, Omaha, NE 68105, USA
- Department of Restorative Sciences, University of Minnesota School of Dentistry, Malcolm Moos Health Sciences Tower, 515 Delaware Street SE, Minneapolis, MN 55455, USA
| | - David B. Marx
- Department of Statistics, 340 Hardin Hall, University of Nebraska-Lincoln, Lincoln, NE 68583, USA
| | - Lauren Ridgway
- Formerly Department of Prosthodontics, Creighton University School of Dentistry, 2109 Cuming Street, Omaha, NE 68102, USA
| | - Bobby Simetich
- Department of Adult Restorative Dentistry, University of Nebraska Medical Center College of Dentistry, 4000 East Campus Loop South, Lincoln, NE 68583, USA
| | - Thiago Carvalho De Sousa
- Department of Dentistry, School of Health Sciences, University of Brasilia (UnB), Brasilia 70910-900, Brazil
| | - Kevin Vakilzadian
- Private Practice, Pine Ridge Dental, 8545 Executive Woods Drive Suite #2, Lincoln, NE 68512, USA
| | - Joel Schulte
- Process Engineer, GSK Consumer Healthcare, 1401 Cornhusker Highway, Lincoln, NE 68517, USA
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13
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Arnold N, Scott J, Bush TR. A review of the characterizations of soft tissues used in human body modeling: Scope, limitations, and the path forward. J Tissue Viability 2023; 32:286-304. [PMID: 36878737 DOI: 10.1016/j.jtv.2023.02.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Revised: 02/06/2023] [Accepted: 02/10/2023] [Indexed: 02/27/2023]
Abstract
Soft tissue material properties are vital to human body models that evaluate interactions between the human body and its environment. Such models evaluate internal stress/strain responses in soft tissues to investigate issues like pressure injuries. Numerous constitutive models and parameters have been used to represent mechanical behavior of soft tissues in biomechanical models under quasi-static loading. However, researchers reported that generic material properties cannot accurately represent specific target populations due to large inter-individual variability. Two challenges that exist are experimental mechanical characterization and constitutive modeling of biological soft tissues and personalization of constitutive parameters using non-invasive, non-destructive bedside testing methods. It is imperative to understand the scope and appropriate applications for reported material properties. Thus, the goal of this paper was to compile studies from which soft tissue material properties were obtained and categorize them by source of tissue samples, methods used to quantify deformation, and material models used to describe tissues. The collected studies displayed wide ranges of material properties, and factors that affected the properties included whether tissue samples were in vivo or ex vivo, from humans or animals, the body region tested, body position during in vivo studies, deformation measurements, and material models used to describe tissues. Because of the factors that affected reported material properties, it is clear that much progress has been made in understanding soft tissue responses to loading, yet there is a need to broaden the scope of reported soft tissue material properties and better match reported properties to appropriate human body models.
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Affiliation(s)
- Nicole Arnold
- Department of Mechanical Engineering, Michigan State University, 428 S Shaw Lane, Rm. 2555 Engineering Building, East Lansing, MI, 48824-1226, USA
| | - Justin Scott
- Department of Mechanical Engineering, Michigan State University, 428 S Shaw Lane, Rm. 2555 Engineering Building, East Lansing, MI, 48824-1226, USA
| | - Tamara Reid Bush
- Department of Mechanical Engineering, Michigan State University, 428 S Shaw Lane, Rm. 2555 Engineering Building, East Lansing, MI, 48824-1226, USA.
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14
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Behrens R, Pliske G, Piatek S, Walcher F, Elkmann N. A statistical model to predict the occurrence of blunt impact injuries on the human hand-arm system. J Biomech 2023; 151:111517. [PMID: 36893519 DOI: 10.1016/j.jbiomech.2023.111517] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Revised: 02/09/2023] [Accepted: 02/22/2023] [Indexed: 03/09/2023]
Abstract
Biomechanical limits based on pain thresholds ensure safety in workplaces where humans and cobots (collaborative robots) work together. Standardization bodies' decision to rely on pain thresholds stems from the assumption that such limits inherently protect humans from injury. This assumption has never been verified, though. This article reports on a study with 22 human subjects in which we studied injury onset in four locations of the hand-arm system using an impact pendulum. During the tests, the impact intensity was slowly increased over several weeks until a blunt injury, i.e., bruising or swelling, appeared in the body locations under load. A statistical model, which calculates injury limits for a given percentile, was developed based on the data. A comparison of our injury limits for the 25th percentile with existing pain limits confirms that pain limits provide suitable protection against impact injuries, albeit not for all body locations.
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Affiliation(s)
- R Behrens
- Fraunhofer IFF, Sandtorstr. 22, 39106 Magdeburg, Germany.
| | - G Pliske
- Department of Trauma Surgery, Otto von Guericke University, Leipziger Str. 44, 39120 Magdeburg, Germany
| | - S Piatek
- Department of Trauma Surgery, Otto von Guericke University, Leipziger Str. 44, 39120 Magdeburg, Germany
| | - F Walcher
- Department of Trauma Surgery, Otto von Guericke University, Leipziger Str. 44, 39120 Magdeburg, Germany
| | - N Elkmann
- Fraunhofer IFF, Sandtorstr. 22, 39106 Magdeburg, Germany
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15
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Rodriguez AJ, Boonya-Ananta MT, Gonzalez M, Le VND, Fine J, Palacios C, McShane MJ, Coté GL, Ramella-Roman JC. Skin optical properties in the obese and their relation to body mass index: a review. JOURNAL OF BIOMEDICAL OPTICS 2022; 27:030902. [PMID: 35352513 PMCID: PMC8963797 DOI: 10.1117/1.jbo.27.3.030902] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Accepted: 02/28/2022] [Indexed: 06/14/2023]
Abstract
SIGNIFICANCE Obesity is a worldwide epidemic contributing directly to several cardiovascular risk factors including hypertension and type 2 diabetes. Wearable devices are becoming better at quantifying biomarkers relevant for the management of health and fitness. Unfortunately, both anecdotal evidence and recent studies indicate that some wearables have higher levels of error when utilized by populations with darker skin tones and high body mass index (BMI). There is an urgent need for a better evaluation of the limits of wearable health technologies when used by obese individuals. AIMS (1) To review the current know-how on changes due to obesity in the skin epidermis, dermis, and subcutis that could affect the skin optical properties; (2) for the green wavelength range, to evaluate the difference in absorption and scattering coefficients from the abdominal skin between individuals with and without elevated BMI. The changes include alterations in layer thickness and cell size, as well as significant differences in chromophores and scatterer content, e.g., water, hemoglobin, collagen, and lipids. APPROACH We have summarized literature pertaining to changes in skin and its components in obesity and report the results of our search using articles published between years 1971 and 2020. A linear model was used to demonstrate the absorption and reduced scattering coefficient of the abdominal skin of individuals with and without elevated BMI in the green wavelength range (530 to 550 nm) that is typically found in most wearables. RESULTS The general trends indicate a decrease in absorption for both dermis and subcutis and an increase in reduced scattering for both epidermis and dermis. At 544-nm wavelength, a typical wavelength used for photoplethysmography (PPG), the absorption coefficient's relative percentage difference between high and low BMI skin, was 49% in the subcutis, 19% in the dermis, and negligible in the epidermis, whereas the reduced scattering coefficient relative difference was 21%, 29%, and 165% respectively. CONCLUSIONS These findings suggest that there could be significant errors in the output of optical devices used for monitoring health and fitness if changes due to obesity are not accounted for in their design.
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Affiliation(s)
- Andres J. Rodriguez
- Florida International University, Department of Biomedical Engineering, Miami, Florida, United States
| | | | - Mariacarla Gonzalez
- Florida International University, Department of Biomedical Engineering, Miami, Florida, United States
| | - Vinh Nguyen Du Le
- Florida International University, Department of Biomedical Engineering, Miami, Florida, United States
| | - Jesse Fine
- Texas A&M University, Department of Biomedical Engineering, College Station, Texas, United States
| | - Cristina Palacios
- Florida International University, Robert Stempel College of Public Health and Social Work, Miami, Florida, United States
| | - Mike J. McShane
- Texas A&M University, Department of Biomedical Engineering, College Station, Texas, United States
- Texas A&M University, TEES Center for Remote Health Technologies and Systems, College Station, Texas, United States
- Texas A&M University, Department of Material Science and Engineering, College Station, Texas, United States
| | - Gerard L. Coté
- Texas A&M University, Department of Biomedical Engineering, College Station, Texas, United States
- Texas A&M University, TEES Center for Remote Health Technologies and Systems, College Station, Texas, United States
| | - Jessica C. Ramella-Roman
- Florida International University, Department of Biomedical Engineering, Miami, Florida, United States
- Florida International University, Herbert Wertheim College of Medicine, Miami, Florida, United States
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16
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Plater EB, Seto VS, Peters RM, Bent LR. Remote Subthreshold Stimulation Enhances Skin Sensitivity in the Lower Extremity. Front Hum Neurosci 2022; 15:789271. [PMID: 35002660 PMCID: PMC8727473 DOI: 10.3389/fnhum.2021.789271] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Accepted: 11/19/2021] [Indexed: 11/13/2022] Open
Abstract
Foot sole skin interfaces with the ground and contributes to successful balance. In situations with reduced sensitivity in the glabrous foot skin, stochastic resonance (SR) improves skin sensitivity by adding tactile noise. Some situations, however, involve an interface comprised of hairy skin, which has higher thresholds for sensitivity. For example, in lower extremity amputation the residual limb is comprised of hairy leg skin. The main objective of this study was to determine if SR improves skin sensitivity in hairy skin, and whether a specific intensity of noise is most effective. Secondary objectives were to compare the effect between locations, ages and modalities. In 60 healthy participants a vibrotactile (test) input was delivered at the lower extremity concurrently with a second, noisy stimulus applied more proximally. The presence of a remote SR effect was tested in 15 young participants using electrotactile noise at the calf. Secondary objectives were tested in separate groups of 15 subjects and differed by substituting for one of the three variables: vibrotactile noise, heel site, and with older participants. A forced-choice protocol was used to determine detection ability of the subthreshold vibration test input with varying noise levels applied simultaneously (0, 20, 40, 60, 80, and 100% of perceptual threshold). An SR effect was identified when increased detection of the input was obtained at any level of noise versus no noise. It was found that all four test groups demonstrated evidence of SR: 33–47% of individuals showed better detection of the input with added noise. The SR effect did not appear consistently at any specific noise level for any of the groups, and none of the variables showed a superior ability to evoke SR. Interestingly, in approximately 33% of cases, threshold values fluctuated throughout testing. While this work has provided evidence that SR can enhance the perception of a vibrotactile input in hairy skin, these data suggest that the ability to repeatably show an SR effect relies on maintaining a consistent threshold.
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Affiliation(s)
- Emma B Plater
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, ON, Canada
| | - Vivian S Seto
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, ON, Canada
| | - Ryan M Peters
- Faculty of Kinesiology, University of Calgary, Calgary, AB, Canada
| | - Leah R Bent
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, ON, Canada
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17
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Olthof NA, Coppieters MW, Moseley GL, Sterling M, Chippindall DJ, Harvie DS. Modernising tactile acuity assessment; clinimetrics of semi-automated tests and effects of age, sex and anthropometry on performance. PeerJ 2021; 9:e12192. [PMID: 35070517 PMCID: PMC8759376 DOI: 10.7717/peerj.12192] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Accepted: 08/31/2021] [Indexed: 11/24/2022] Open
Abstract
Background Reduced tactile acuity has been observed in several chronic pain conditions and has been proposed as a clinical indicator of somatosensory impairments related to the condition. As some interventions targeting these impairments have resulted in pain reduction, assessing tactile acuity may have significant clinical potential. While two-point discrimination threshold (TPDT) is a popular method of assessing tactile acuity, large measurement error has been observed (impeding responsiveness) and its validity has been questioned. The recently developed semi-automated ‘imprint Tactile Acuity Device’ (iTAD) may improve tactile acuity assessment, but clinimetric properties of its scores (accuracy score, response time and rate correct score) need further examination. Aims Experiment 1: To determine inter-rater reliability and measurement error of TPDT and iTAD assessments. Experiment 2: To determine internal consistencies and floor or ceiling effects of iTAD scores, and investigate effects of age, sex, and anthropometry on performance. Methods Experiment 1: To assess inter-rater reliability (ICC(2,1)) and measurement error (coefficient of variation (CoV)), three assessors each performed TPDT and iTAD assessments at the neck in forty healthy participants. Experiment 2: To assess internal consistency (ICC(2,k)) and floor or ceiling effects (skewness z-scores), one hundred healthy participants performed the iTAD’s localisation and orientation tests. Balanced for sex, participants were equally divided over five age brackets (18–30, 31–40, 41–50, 51–60 and 61–70). Age, sex, body mass index (BMI) and neck surface area were assessed to examine their direct (using multiple linear regression analysis) and indirect (using sequential mediation analysis) relationship with iTAD scores. Results Mean ICC(2,1) was moderate for TPDT (0.70) and moderate-to-good for the various iTAD scores (0.65–0.86). The CoV was 25.3% for TPDT and ranged from 6.1% to 16.5% for iTAD scores. Internal consistency was high for both iTAD accuracy scores (ICC(2,6) = 0.84; ICC(2,4) = 0.86). No overt floor or ceiling effects were detected (all skewness z-scores < 3.29). Accuracy scores were only directly related to age (decreasing with increasing age) and sex (higher for men). Discussion Although reliability was similar, iTAD scores demonstrated less measurement error than TPDT indicating a potential for better responsiveness to treatment effects. Further, unlike previously reported for TPDT, iTAD scores appeared independent of anthropometry, which simplifies interpretation. Additionally, the iTAD assesses multiple aspects of tactile processing which may provide a more comprehensive evaluation of tactile acuity. Taken together, the iTAD shows promise in measuring tactile acuity, but patient studies are needed to verify clinical relevance.
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Affiliation(s)
- Nick A. Olthof
- School of Health Sciences and Social Work, Griffith University, Brisbane and Gold Coast, QLD, Australia
- Menzies Health Institute Queensland, Griffith University, Brisbane and Gold Coast, QLD, Australia
| | - Michel W. Coppieters
- Menzies Health Institute Queensland, Griffith University, Brisbane and Gold Coast, QLD, Australia
- Amsterdam Movement Sciences, Faculty of Behavioural and Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - G Lorimer Moseley
- IIMPACT in Health, University of South Australia, Kaurna Country, Adelaide, SA, Australia
| | - Michele Sterling
- RECOVER Injury Research Centre, The University of Queensland, Brisbane, QLD, Australia
- NHMRC Centre of Research Excellence in Road Traffic Injury Recovery, The University of Queensland, Brisbane, QLD, Australia
| | - Dylan J. Chippindall
- Menzies Health Institute Queensland, Griffith University, Brisbane and Gold Coast, QLD, Australia
| | - Daniel S. Harvie
- School of Health Sciences and Social Work, Griffith University, Brisbane and Gold Coast, QLD, Australia
- Menzies Health Institute Queensland, Griffith University, Brisbane and Gold Coast, QLD, Australia
- IIMPACT in Health, University of South Australia, Kaurna Country, Adelaide, SA, Australia
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18
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Mancino G, Miro C, Di Cicco E, Dentice M. Thyroid hormone action in epidermal development and homeostasis and its implications in the pathophysiology of the skin. J Endocrinol Invest 2021; 44:1571-1579. [PMID: 33683663 PMCID: PMC8285348 DOI: 10.1007/s40618-020-01492-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Accepted: 12/22/2020] [Indexed: 02/07/2023]
Abstract
Thyroid hormones (THs) are key endocrine regulators of tissue development and homeostasis. They are constantly released into the bloodstream and help to regulate many cell functions. The principal products released by the follicular epithelial cells are T3 and T4. T4, which is the less active form of TH, is produced in greater amounts than T3, which is the most active form of TH. This mechanism highlights the importance of the peripheral regulation of TH levels that goes beyond the central axis. Skin, muscle, liver, bone and heart are finely regulated by TH. In particular, skin is among the target organs most influenced by TH, which is essential for skin homeostasis. Accordingly, skin diseases are associated with an altered thyroid status. Alopecia, dermatitis and vitiligo are associated with thyroiditis and alopecia and eczema are frequently correlated with the Graves' disease. However, only in recent decades have studies started to clarify the molecular mechanisms underlying the effects of TH in epidermal homeostasis. Herein, we summarize the most frequent clinical epidermal alterations linked to thyroid diseases and review the principal mechanisms involved in TH control of keratinocyte proliferation and functional differentiation. Our aim is to define the open questions in this field that are beginning to be elucidated thanks to the advent of mouse models of altered TH metabolism and to obtain novel insights into the physiopathological consequences of TH metabolism on the skin.
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Affiliation(s)
- G Mancino
- Department of Clinical Medicine and Surgery, University of Naples "Federico II", Via S. Pansini 5, 80131, Naples, Italy
| | - C Miro
- Department of Clinical Medicine and Surgery, University of Naples "Federico II", Via S. Pansini 5, 80131, Naples, Italy
| | - E Di Cicco
- Department of Clinical Medicine and Surgery, University of Naples "Federico II", Via S. Pansini 5, 80131, Naples, Italy
| | - M Dentice
- Department of Clinical Medicine and Surgery, University of Naples "Federico II", Via S. Pansini 5, 80131, Naples, Italy.
- CEINGE-Biotecnologie Avanzate Scarl, Naples, Italy.
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19
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Keystone Flaps for Coverage of Defects in the Posterior Neck and Lower Occipital Scalp: A Retrospective Clinical Study. J Craniofac Surg 2021; 32:1813-1816. [PMID: 33654029 DOI: 10.1097/scs.0000000000007581] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
ABSTRACT The coverage of the posterior neck and lower occipital scalp defects should be approached carefully. Thick, stiff, and inelastic skin properties of these areas tend to make coverage of even small defects difficult. Herein, the authors present a retrospective review of our experience with posterior neck and lower occipital scalp reconstruction using the keystone flap (KF) and describe the expanding versatility of KF reconstruction. The medical records of 17 patients who underwent KF reconstruction to cover the posterior neck and lower occipital defect from April 2017 to May 2020 were reviewed. Clinical and operative data were collected. All defects were successfully covered with the KFs. The defect sizes ranged from 2.5 × 3.5 cm to 6 × 11 cm, and the flap sizes ranged from 3 × 5.5 cm to 9 × 18 cm. All flaps fully survived, although marginal maceration developed in one case; however, it healed with conservative management. The final results were favorable, and all patients were satisfied with their final outcomes. Consequently, the KF can be considered as a good reconstruction modality with few complications and provides an alternative to other reconstructive options for coverage of the posterior neck and lower occipital defects.
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20
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Wilkinson HN, Hardman MJ. A role for estrogen in skin ageing and dermal biomechanics. Mech Ageing Dev 2021; 197:111513. [PMID: 34044023 DOI: 10.1016/j.mad.2021.111513] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 05/20/2021] [Accepted: 05/22/2021] [Indexed: 01/11/2023]
Abstract
The skin is the body's primary defence against the external environment, preventing infection and desiccation. Therefore, alterations to skin homeostasis, for example with skin ageing, increase susceptibility to skin disease and injury. Skin biological ageing is uniquely influenced by a combination of intrinsic and extrinsic (primarily photoageing) factors, with differential effects on skin structure and function. Interestingly, skin architecture rapidly changes following the menopause, as a direct result of reduced circulating 17β-estradiol. The traditional clinical benefit of estrogens are supported by recent experimental data, where 17β-estradiol supplementation prevents age-related decline in the skin's structural and mechanical properties. However, the off-target effects of 17β-estradiol continue to challenge therapeutic application. Here we discuss how ageing alters the physiological and structural properties of the dermal extracellular matrix, and explore how estrogen receptor-targeted therapies may restore the mechanical defects associated with skin ageing.
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Affiliation(s)
- Holly N Wilkinson
- Centre for Atherothrombosis and Metabolic Disease, Hull York Medical School, The University of Hull, HU6 7RX, United Kingdom
| | - Matthew J Hardman
- Centre for Atherothrombosis and Metabolic Disease, Hull York Medical School, The University of Hull, HU6 7RX, United Kingdom.
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21
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Fine J, Branan KL, Rodriguez AJ, Boonya-ananta T, Ajmal, Ramella-Roman JC, McShane MJ, Coté GL. Sources of Inaccuracy in Photoplethysmography for Continuous Cardiovascular Monitoring. BIOSENSORS 2021; 11:126. [PMID: 33923469 PMCID: PMC8073123 DOI: 10.3390/bios11040126] [Citation(s) in RCA: 91] [Impact Index Per Article: 30.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 03/30/2021] [Accepted: 04/09/2021] [Indexed: 12/14/2022]
Abstract
Photoplethysmography (PPG) is a low-cost, noninvasive optical technique that uses change in light transmission with changes in blood volume within tissue to provide information for cardiovascular health and fitness. As remote health and wearable medical devices become more prevalent, PPG devices are being developed as part of wearable systems to monitor parameters such as heart rate (HR) that do not require complex analysis of the PPG waveform. However, complex analyses of the PPG waveform yield valuable clinical information, such as: blood pressure, respiratory information, sympathetic nervous system activity, and heart rate variability. Systems aiming to derive such complex parameters do not always account for realistic sources of noise, as testing is performed within controlled parameter spaces. A wearable monitoring tool to be used beyond fitness and heart rate must account for noise sources originating from individual patient variations (e.g., skin tone, obesity, age, and gender), physiology (e.g., respiration, venous pulsation, body site of measurement, and body temperature), and external perturbations of the device itself (e.g., motion artifact, ambient light, and applied pressure to the skin). Here, we present a comprehensive review of the literature that aims to summarize these noise sources for future PPG device development for use in health monitoring.
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Affiliation(s)
- Jesse Fine
- Department of Biomedical Engineering, Texas A&M University, College Station, TX 77843, USA; (J.F.); (K.L.B.)
| | - Kimberly L. Branan
- Department of Biomedical Engineering, Texas A&M University, College Station, TX 77843, USA; (J.F.); (K.L.B.)
| | - Andres J. Rodriguez
- Department of Biomedical Engineering, Florida International University, Miami, FL 33174, USA; (A.J.R.); (T.B.-a.); (A.); (J.C.R.-R.)
| | - Tananant Boonya-ananta
- Department of Biomedical Engineering, Florida International University, Miami, FL 33174, USA; (A.J.R.); (T.B.-a.); (A.); (J.C.R.-R.)
| | - Ajmal
- Department of Biomedical Engineering, Florida International University, Miami, FL 33174, USA; (A.J.R.); (T.B.-a.); (A.); (J.C.R.-R.)
| | - Jessica C. Ramella-Roman
- Department of Biomedical Engineering, Florida International University, Miami, FL 33174, USA; (A.J.R.); (T.B.-a.); (A.); (J.C.R.-R.)
- Herbert Wertheim College of Medicine, Florida International University, Miami, FL 33199, USA
| | - Michael J. McShane
- Department of Biomedical Engineering, Texas A&M University, College Station, TX 77843, USA; (J.F.); (K.L.B.)
- Department of Materials Science and Engineering, Texas A&M University, College Station, TX 77843, USA
- Center for Remote Health Technologies and Systems, Texas A&M Engineering Experimentation Station, Texas A&M University, College Station, TX 77843, USA
| | - Gerard L. Coté
- Department of Biomedical Engineering, Texas A&M University, College Station, TX 77843, USA; (J.F.); (K.L.B.)
- Center for Remote Health Technologies and Systems, Texas A&M Engineering Experimentation Station, Texas A&M University, College Station, TX 77843, USA
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García-Guzmán JJ, Pérez-Ràfols C, Cuartero M, Crespo GA. Microneedle based electrochemical (Bio)Sensing: Towards decentralized and continuous health status monitoring. Trends Analyt Chem 2021. [DOI: 10.1016/j.trac.2020.116148] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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Zhou K, Feng K, Li C, Huang Z. A Weighted Average Phase Velocity Inversion Model for Depth-Resolved Elasticity Evaluation in Human Skin In-Vivo. IEEE Trans Biomed Eng 2020; 68:1969-1977. [PMID: 33326373 DOI: 10.1109/tbme.2020.3045133] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECTIVE In current surface acoustic wave (SAW) elastography field, wavelength-depth inversion model is a straightforward and widely used inversion model for depth-resolved elasticity profile reconstruction. However, the elasticity directly evaluated from the wavelength-depth relationship is biased. Thus, a new inversion model, termed weighted average phase velocity (WAPV) inversion model, is proposed to provide depth-resolved Young's modulus estimate with better accuracy. METHODS The forward model for SAW phase velocity dispersion curve generation was derived from the numerical simulations of SAWs in layered materials, and inversion was implemented by matching the measured phase velocity dispersion curve to the one generated from the forward model using the least squares fitting. Three two-layer agar phantoms with different top-layer thicknesses and one three-layer agar phantom were tested to validate the proposed inversion model. Then the model was demonstrated on human skin at various sites (palm, forearm and back of hand) in-vivo. RESULTS In multi-layered agar phantoms, depth-resolved elasticity estimates provided by the model have a maximal total inversion error of 15.2% per sample after inversion error compensation. In in-vivo human skin, the quantified bulk Young's moduli (palm: 212 ± 78 kPa; forearm: 32 ± 11 kPa and back of hand: 29 ± 8 kPa) are comparable to the reference values in the literature. CONCLUSION The WAPV inversion model can provide accurate depth-resolved Young's modulus estimates in layered biological soft tissues. SIGNIFICANCE The proposed model can predict depth-resolved elasticity in layered biological soft tissues with a reasonable accuracy which traditional wavelength-depth inversion model cannot provide.
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Hamed S, Almalty AM, Alkhatib HS. The cutaneous effects of long-term use of Dead Sea mud on healthy skin: a 4-week study. Int J Dermatol 2020; 60:332-339. [PMID: 33283890 DOI: 10.1111/ijd.15304] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 09/20/2020] [Accepted: 10/16/2020] [Indexed: 11/30/2022]
Abstract
PURPOSE To investigate the effects of various types of Dead Sea mud (DSM) on skin barrier properties over a period of four weeks. METHODS The effects of a 4-week application of three types of DSM (as is mud, mud with extra Dead Sea salt, and over the shelf mud) on the barrier properties of normal skin were investigated. Preparations were applied onto forearms of healthy volunteers every other day for 4 weeks, and skin hydration, transepidermal water loss (TEWL), melanin, erythema level, skin pH, skin elasticity, dermal thickness, and collagen content were measured at predefined circular areas on subjects' forearms at baseline, week 1, week 2, and week 4 during the treatment phase and on week 5 following a 1-week regression period in which no mud was applied. RESULTS The use of DSM for 4 weeks was well tolerated with no noticeable changes in TEWL, skin pH, melanin, and erythema levels. A slight firming effect was observed in the forearms treated with salted DSM. Skin hydration was not significantly affected by any type of DSM. However, a slight drying effect of "as is" and "salted" DSM and slight hydration effect of "over the shelf" DSM were observed. This effect could be attributed to the content of DSM rather than to disruption of skin integrity as confirmed by TEWL values. CONCLUSION Long-term use of all types of DSM did not compromise the barrier integrity of the skin. This provides dermatologists with needed information on safety of DSM and lack of skin disruption activity upon long-term use.
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Affiliation(s)
- Saja Hamed
- Faculty of Pharmaceutical Sciences, The Hashemite University, Zarqa, Jordan
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Gnyawali SC, Sinha M, El Masry MS, Wulff B, Ghatak S, Soto-Gonzalez F, Wilgus TA, Roy S, Sen CK. High resolution ultrasound imaging for repeated measure of wound tissue morphometry, biomechanics and hemodynamics under fetal, adult and diabetic conditions. PLoS One 2020; 15:e0241831. [PMID: 33227015 PMCID: PMC7682876 DOI: 10.1371/journal.pone.0241831] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Accepted: 10/21/2020] [Indexed: 02/07/2023] Open
Abstract
Non-invasive, repeated interrogation of the same wound is necessary to understand the tissue repair continuum. In this work, we sought to test the significance of non-invasive high-frequency high-resolution ultrasound technology for such interrogation. High-frequency high-resolution ultrasound imaging was employed to investigate wound healing under fetal and adult conditions. Quantitative tissue cellularity and elastic strain was obtained for visualization of unresolved inflammation using Vevo strain software. Hemodynamic properties of the blood flow in the artery supplying the wound-site were studied using color Doppler flow imaging. Non-invasive monitoring of fetal and adult wound healing provided unprecedented biomechanical and functional insight. Fetal wounds showed highly accelerated closure with transient perturbation of wound tissue cellularity. Fetal hemodynamics was unique in that sharp fall in arterial pulse pressure (APP) which was rapidly restored within 48h post-wounding. In adults, APP transiently increased post-wounding before returning to the pre-wounding levels by d10 post-wounding. The pattern of change in the elasticity of wound-edge tissue of diabetics was strikingly different. Severe strain acquired during the early inflammatory phase persisted with a slower recovery of elasticity compared to that of the non-diabetic group. Wound bed of adult diabetic mice (db/db) showed persistent hypercellularity compared to littermate controls (db/+) indicative of prolonged inflammation. Normal skin strain of db/+ and db/db were asynchronous. In db/db, severe strain acquired during the early inflammatory phase persisted with a slower recovery of elasticity compared to that of non-diabetics. This study showcases a versatile clinically relevant imaging platform suitable for real-time analyses of functional wound healing.
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Affiliation(s)
- Surya C. Gnyawali
- Department of Surgery, Davis Heart and Lung Research Institute, Center for Regenerative Medicine & Cell-Based Therapies, The Ohio State University Wexner Medical Center, Columbus, OH, United States of America
| | - Mithun Sinha
- Department of Surgery, Davis Heart and Lung Research Institute, Center for Regenerative Medicine & Cell-Based Therapies, The Ohio State University Wexner Medical Center, Columbus, OH, United States of America
- Department of Surgery, IUH Comprehensive Wound Center, Indiana Center for Regenerative Medicine and Engineering, Indiana University School of Medicine, Indianapolis, IN, United States of America
| | - Mohamed S. El Masry
- Department of Surgery, Davis Heart and Lung Research Institute, Center for Regenerative Medicine & Cell-Based Therapies, The Ohio State University Wexner Medical Center, Columbus, OH, United States of America
- Department of Surgery, IUH Comprehensive Wound Center, Indiana Center for Regenerative Medicine and Engineering, Indiana University School of Medicine, Indianapolis, IN, United States of America
- Department of Plastic and Reconstructive Surgery, Zagazig University, Zagazig, Egypt
| | - Brian Wulff
- Department of Pathology, The Ohio State University Wexner Medical Center, Columbus, OH, United States of America
| | - Subhadip Ghatak
- Department of Surgery, Davis Heart and Lung Research Institute, Center for Regenerative Medicine & Cell-Based Therapies, The Ohio State University Wexner Medical Center, Columbus, OH, United States of America
- Department of Surgery, IUH Comprehensive Wound Center, Indiana Center for Regenerative Medicine and Engineering, Indiana University School of Medicine, Indianapolis, IN, United States of America
| | - Fidel Soto-Gonzalez
- Department of Surgery, Davis Heart and Lung Research Institute, Center for Regenerative Medicine & Cell-Based Therapies, The Ohio State University Wexner Medical Center, Columbus, OH, United States of America
| | - Traci A. Wilgus
- Department of Pathology, The Ohio State University Wexner Medical Center, Columbus, OH, United States of America
| | - Sashwati Roy
- Department of Surgery, Davis Heart and Lung Research Institute, Center for Regenerative Medicine & Cell-Based Therapies, The Ohio State University Wexner Medical Center, Columbus, OH, United States of America
- Department of Surgery, IUH Comprehensive Wound Center, Indiana Center for Regenerative Medicine and Engineering, Indiana University School of Medicine, Indianapolis, IN, United States of America
| | - Chandan K. Sen
- Department of Surgery, Davis Heart and Lung Research Institute, Center for Regenerative Medicine & Cell-Based Therapies, The Ohio State University Wexner Medical Center, Columbus, OH, United States of America
- Department of Surgery, IUH Comprehensive Wound Center, Indiana Center for Regenerative Medicine and Engineering, Indiana University School of Medicine, Indianapolis, IN, United States of America
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Nkengne A, Robic J, Lua BL. Self-perceived and objective measurements of facial puffiness in Chinese women. Skin Res Technol 2020; 27:385-392. [PMID: 33089925 DOI: 10.1111/srt.12955] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2020] [Revised: 07/23/2020] [Accepted: 09/07/2020] [Indexed: 11/27/2022]
Abstract
BACKGROUND Facial puffiness, caused by mild or normal fluid retention, commonly experienced by women, may not pose a health risk, but it can be a cause of cosmetic concern. The objectives of this study were to determine whether self-perceived facial puffiness can be measured objectively. MATERIALS AND METHODS A total of 151 Chinese women between 20 and 68 years of age were recruited. Facial water content, skin thickness, and elasticity were measured at two time points within a day (visit one occurred when the participants perceived they had facial puffiness; visit two occurred when the participants perceived their facial puffiness had subsided). Participants were also given a rating scale to self-evaluate their puffiness and firmness at different regions of the face. RESULTS The participants could perceive a difference in facial puffiness between the two visits. Water content and skin thickness were significantly higher in all regions of the face for all participants during the first visit. Skin elasticity was also significantly different between visits one and two. There was a significant increase in water content and skin thickness in the lower eyelid region in women who were older than 40 years. CONCLUSION This is the first study to show that self-perceived facial puffiness can be measured objectively and that skin elasticity can change significantly when facial puffiness subsides.
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Graham HK, McConnell JC, Limbert G, Sherratt MJ. How stiff is skin? Exp Dermatol 2020; 28 Suppl 1:4-9. [PMID: 30698873 DOI: 10.1111/exd.13826] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/25/2019] [Indexed: 12/17/2022]
Abstract
The measurement of the mechanical properties of skin (such as stiffness, extensibility and strength) is a key step in characterisation of both dermal ageing and disease mechanisms and in the assessment of tissue-engineered skin replacements. However, the biomechanical terminology and plethora of mathematical analysis approaches can be daunting to those outside the field. As a consequence, mechanical studies are often inaccessible to a significant proportion of the intended audience. Furthermore, devices for the measurement of skin function in vivo generate relative values rather than formal mechanical measures, therefore limiting the ability to compare studies. In this viewpoint essay, we discuss key biomechanical concepts and the influence of technical and biological factors (including the nature of the testing apparatus, length scale, donor age and anatomical site) on measured mechanical properties such as stiffness. Having discussed the current state-of-the-art in macro-mechanical and micromechanical measuring techniques and in mathematical and computational modelling methods, we then make suggestions as to how these approaches, in combination with 3D X-ray imaging and mechanics methods, may be adopted into a single strategy to characterise the mechanical behaviour of skin.
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Affiliation(s)
- Helen K Graham
- Division of Musculoskeletal& Dermatological Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, The University of Manchester, Manchester, UK
| | - James C McConnell
- Division of Cell Matrix Biology & Regenerative Medicine, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, The University of Manchester, Manchester, UK
| | - Georges Limbert
- National Centre for Advanced Tribology at Southampton (nCATS), Bioengineering Science Research Group, Faculty of Engineering and the Environment, University of Southampton, Southampton, UK.,Biomechanics and Mechanobiology Laboratory, Biomedical Engineering Division, Department of Human Biology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Michael J Sherratt
- Division of Cell Matrix Biology & Regenerative Medicine, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, The University of Manchester, Manchester, UK
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Constantin MM, Bucur S, Serban ED, Olteanu R, Bratu OG, Constantin T. Measurement of skin viscoelasticity: A non-invasive approach in allergic contact dermatitis. Exp Ther Med 2020; 20:184. [PMID: 33101474 DOI: 10.3892/etm.2020.9314] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Accepted: 07/15/2020] [Indexed: 12/12/2022] Open
Abstract
Non-invasive bioengineering technologies are constantly being developed, as they can provide useful insights and contribute to the improvement of medical care and scientific education. The purpose of this study was to assess skin viscoelasticity using the suction chamber method in patients with allergic contact dermatitis vs. healthy subjects, before and after applying a moisturizer safety testing cream. This was a prospective controlled study over a 3-year period (March 2016-March 2019), with 81 subjects being divided in two balanced groups: Patients with allergic contact dermatitis and healthy subjects, respectively. The skin viscoelasticity was determined for all subjects with Cutometer®, using the suction method, by performing a dynamic assessment of parameters before and after applying a moisturizing cream. The results indicate a decrease in the elasticity parameters in both groups, indicating an improvement of the elastic properties under the treatment. Skin capacity to return to its previous form after the deformation, i.e., pure elasticity and biological elasticity, showed overall elevated values in the group with contact dermatitis, demonstrating the efficacy of the emollient cream after applying it for 28 days (increase by 11.7 and 4.9% respectively, compared with baseline, when patients had dry, untreated skin). However, in healthy subjects, these parameters do not achieve important values, but they remain rather stable over time with a very slight improvement (6.6% after 28 days). The Cutometer is an easy to use, efficient and widely used instrument for measurements in studies that perform a quantitative assessment of the effectiveness of different formulations intended for application on the skin.
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Affiliation(s)
- Maria-Magdalena Constantin
- The Second Department of Dermatology, Colentina Clinical Hospital, 020125 Bucharest, Romania.,3rd Department, 'Carol Davila' University of Medicine and Pharmacy, 050474 Bucharest, Romania
| | - Stefana Bucur
- The Second Department of Dermatology, Colentina Clinical Hospital, 020125 Bucharest, Romania
| | - Elena-Daniela Serban
- The Second Department of Dermatology, Colentina Clinical Hospital, 020125 Bucharest, Romania
| | - Rodica Olteanu
- The Second Department of Dermatology, Colentina Clinical Hospital, 020125 Bucharest, Romania
| | - Ovidiu Gabriel Bratu
- 3rd Department, 'Carol Davila' University of Medicine and Pharmacy, 050474 Bucharest, Romania.,Urology Department, Emergency University Central Military Hospital, 010825 Bucharest, Romania
| | - Traian Constantin
- 3rd Department, 'Carol Davila' University of Medicine and Pharmacy, 050474 Bucharest, Romania
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29
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Phillips J, Reynolds KJ, Gordon SJ. Dermal thickness and echogenicity using DermaScan C high frequency ultrasound: Methodology and reliability testing in people with and without primary lymphoedema. Skin Res Technol 2020; 26:813-823. [PMID: 32579302 DOI: 10.1111/srt.12880] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Accepted: 05/23/2020] [Indexed: 12/14/2022]
Abstract
BACKGROUND DermaScan C high frequency ultrasound was investigated for image capture and analysis of dermal measures in people with and without primary lymphoedema. METHOD Three repeated images were taken at six sites in people without lymphoedema (NLO). Intra-rater reliability was assessed by taking three sets of measures on images from 10 people and inter-session reliability by capturing three images, lifting the probe from the skin in between. Methods were adjusted, and repeated images from four sites were taken in people with primary lymphoedema (PLO) and reliability re-assessed. RESULTS Intra-rater reliability in NLO and PLO for echogenicity measures were excellent (NLO ICC(3,1) : .989; PLO .997) across all sites and specific to each site (calf: ICC(3,1) : .989; and foot: ICC(3,1) : .999, respectively). Inter-session reliability was moderate for NLO (ICC(3,1) : .727), improving after method modifications for PLO (ICC(3,1) : .916). When investigated by site, inter-session reliability was good in the foot (ICC(3,1) : .811) and moderate in the calf (ICC(3,1) : .616). Mean thickness analysed by site resulted in good inter-session reliability only in the foot (ICC(3,1) .838). CONCLUSION Intra-rater reliability was excellent using the DermaScan C for dermal measures in people with primary lymphoedema. Inter-session reliability required particular attention to method and gain settings.
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Affiliation(s)
- Jane Phillips
- College of Nursing & Health Sciences, Caring Futures Institute, Flinders University, Adelaide, SA, Australia.,Murdoch Children's Research Institute, Parkville, Vic., Australia
| | - Karen J Reynolds
- College of Science & Engineering, Medical Device Research Institute, Flinders University, Adelaide, SA, Australia
| | - Susan J Gordon
- College of Nursing & Health Sciences, Caring Futures Institute, Flinders University, Adelaide, SA, Australia
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30
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DeJong H, Abbott S, Zelesco M, Spilsbury K, Ziman M, Kennedy BF, Martin L, Wood FM. Objective quantification of burn scar stiffness using shear-wave elastography: Initial evidence of validity. Burns 2020; 46:1787-1798. [PMID: 32534890 DOI: 10.1016/j.burns.2020.05.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Revised: 04/21/2020] [Accepted: 05/12/2020] [Indexed: 12/18/2022]
Abstract
Shear-wave elastography (SWE) is an ultrasound based technology that can provide reliable measurements (velocity) of scar stiffness. The aim of this research was to evaluate the concurrent validity of using both the measured velocity and the calculated difference in velocity between scars and matched controls, in addition to evaluating potential patient factors that may influence the interpretation of the measurements. METHODS A cross-sectional study of 32 participants, with 48 burn scars and 48 matched contralateral control sites were evaluated with SWE, the Vancouver Scar Scale (VSS) and the Patient and Observer Scar Assessment Scale (POSAS) tactile sub-scores. RESULTS Spearman's rho demonstrated high correlations (r > 0.7) between the measured scar velocity and both the POSAS and VSS pliability sub-scores, whereas moderate correlations (r > 0.6) were found with the calculated difference in velocity. Regression analysis indicated that the association of increased velocity in scars, varied by length of time after burn injury and gender. Body location and Fitzpatrick skin type also demonstrated significant associations with velocity, whereas age did not. CONCLUSION SWE shows potential as a novel tool to quantify burn scar stiffness, however patient factors need to be considered when interpreting results. Further research is recommended on a larger variety of scars to support the findings.
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Affiliation(s)
- Helen DeJong
- Perth Scar and Pain Clinic, 2/5 Norfolk Street, Fremantle, Western Australia 6160, Australia; School of Medical and Health Science, Edith Cowan University, 270 Joondalup Drive, Joondalup, Western Australia 6027, Australia; BRITElab, Harry Perkins Institute of Medical Research, QEII Medical Centre Nedlands and Centre for Medical Research, The University of Western Australia, 35 Stirling Hwy, Crawley, Western Australia 6009, Australia; Fiona Wood Foundation, Fiona Stanley Hospital, 11 Robin Warren Dr, Murdoch, Western Australian 6150, Australia.
| | - Steven Abbott
- Department of Medical Imaging, Fiona Stanley Hospital, 11 Robin Warren Dr, Murdoch, Western Australian, 6150, Australia
| | - Marilyn Zelesco
- Department of Medical Imaging, Fiona Stanley Hospital, 11 Robin Warren Dr, Murdoch, Western Australian, 6150, Australia
| | - Katrina Spilsbury
- Institute for Health Research, University of Notre Dame Australia, Fremantle, Western Australia, Australia
| | - Melanie Ziman
- School of Medical and Health Science, Edith Cowan University, 270 Joondalup Drive, Joondalup, Western Australia 6027, Australia; School of Biomedical Science, The University of Western Australia, 35 Stirling Hwy, Crawley, Western Australia 6009, Australia
| | - Brendan F Kennedy
- BRITElab, Harry Perkins Institute of Medical Research, QEII Medical Centre Nedlands and Centre for Medical Research, The University of Western Australia, 35 Stirling Hwy, Crawley, Western Australia 6009, Australia; Department of Electrical, Electronic and Computer Engineering, School of Engineering, The University of Western Australia, 35 Stirling Hwy, Crawley, 6009, Western Australia, Australia; Australian Research Council Centre for Personalised Therapeutics Technologies, Australia
| | - Lisa Martin
- Fiona Wood Foundation, Fiona Stanley Hospital, 11 Robin Warren Dr, Murdoch, Western Australian 6150, Australia
| | - Fiona M Wood
- Fiona Wood Foundation, Fiona Stanley Hospital, 11 Robin Warren Dr, Murdoch, Western Australian 6150, Australia; Burn Injury Research Unit, The University of Western Australia, 35 Stirling Hwy, Crawley, Western Australia 6009, Australia; Burn Service of Western Australia, Fiona Stanley Hospital, 11 Robin Warren Dr, Murdoch, Western Australian 6150, Australia
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Vu LQ, Kim KH, Schulze LJH, Rajulu SL. Lumbar posture assessment with fabric strain sensors. Comput Biol Med 2020; 118:103624. [PMID: 32174329 DOI: 10.1016/j.compbiomed.2020.103624] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Revised: 01/08/2020] [Accepted: 01/17/2020] [Indexed: 11/19/2022]
Abstract
Astronauts are at risk for low back pain and injury during extravehicular activity because of the deconditioning of the lumbar region and biomechanical demands associated with wearing a spacesuit. To understand and mitigate injury risks, it is necessary to study the lumbar kinematics of astronauts inside their spacesuit. To expand on previous efforts, the purpose of this study was to develop and test a generalizable method to assess complex lumbar motion using 10 fabric strain sensors placed on the torso. Anatomical landmark positions and corresponding sensor measurements were collected from 12 male study participants performing 16 static lumbar postures. A multilayer principal component and regression-based model was constructed to estimate lumbar joint angles from the sensor measurements. Good lumbar joint angle estimation was observed (<9° mean error) from flexion and lateral bending joint angles, and lower accuracy (13.7° mean error) was observed from axial rotation joint angles. With continued development, this method can become a useful technique for measuring suited lumbar motion and could potentially be extrapolated to civilian work applications.
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Affiliation(s)
- Linh Q Vu
- MEI Technologies, 2101 E NASA Pkwy, Houston, TX, 77058, USA.
| | - K Han Kim
- Leidos Innovations, 2101 E NASA Pkwy, Houston, TX, 77058, USA
| | | | - Sudhakar L Rajulu
- NASA Johnson Space Center, 2101 E NASA Pkwy, Houston, TX, 77058, USA
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Lakhani P, Dwivedi KK, Kumar N. Directional dependent variation in mechanical properties of planar anisotropic porcine skin tissue. J Mech Behav Biomed Mater 2020; 104:103693. [PMID: 32174437 DOI: 10.1016/j.jmbbm.2020.103693] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2019] [Revised: 11/23/2019] [Accepted: 02/09/2020] [Indexed: 11/26/2022]
Abstract
Nonlinear and anisotropic mechanical behavior of skin is essential in various applications such as dermatology, cosmetic products, forensic science, and computational studies. The present study quantifies the mechanical anisotropy of skin using the bulge method and full-field imaging technique. In bulging, the saline solution at 37 °C mimics the in vivo body temperature and fluid conditions, and all experiments were performed in the control environment. Assumption of thin spherical shell membrane theory and imaging techniques were implemented to obtain the anisotropic stress strain relations. Further, stress strain relations at an interval of 10° were calculated to obtain the variation in modulus with direction. Histological examinations were performed to signify the role of the collagen fibers orientation on the mechanical properties. The maximum and minimum linear modulus and collagen fiber orientation intensity were found in good agreement. The angular difference between maximum and minimum linear modulus and orientation intensity was found 71° ± 7° and 76° ± 5° respectively, and the percentage difference was 43.4 ± 8.2 and 52.5 ± 6.4 respectively. Further, a significant difference in the maximum and minimum collagen orientation intensity between the untested and tested specimens indicates the realignment of the fibers. Additionally, a cubic polynomial empirical relation was established to calculate the quantitative variation in the apparent modulus with the directions, which serves for the anisotropic modeling of the skin. The experimental technique used in this study can be applied for anisotropic quantification of planar soft tissues as well as can be utilized to imitate the tissue expansion procedure used in reconstructive surgery.
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Affiliation(s)
- Piyush Lakhani
- Department of Mechanical Engineering, Indian Institute of Technology Ropar, Rupnagar, 140001, Punjab, India
| | - Krashn K Dwivedi
- Center for Biomedical Engineering, Indian Institute of Technology Ropar, Rupnagar, 140001, Punjab, India
| | - Navin Kumar
- Department of Mechanical Engineering, Indian Institute of Technology Ropar, Rupnagar, 140001, Punjab, India.
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Flament F, Francois G, Seyrek I, Saint‐Leger D. Age‐related changes to characteristics of the human eyes in women from six different ethnicities. Skin Res Technol 2020; 26:520-528. [DOI: 10.1111/srt.12824] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Accepted: 11/09/2019] [Indexed: 10/25/2022]
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Keystone-design perforator island flaps for the management of complicated epidermoid cysts on the back. Sci Rep 2019; 9:14699. [PMID: 31605009 PMCID: PMC6789127 DOI: 10.1038/s41598-019-51289-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Accepted: 09/28/2019] [Indexed: 02/08/2023] Open
Abstract
Complicated epidermoid cysts (ECs) occur commonly on the back, but few reports have described their management. We present our experience in managing patients with ECs on the back using a keystone-design perforator island flap (KDPIF) reconstruction, thereby focusing on reduction and redistribution of wound tension. Altogether, 15 patients (average age, 48.067 ± 14.868 years) underwent KDPIF reconstructions after complete excision of complicated ECs on the back. We retrospectively reviewed the medical records and clinical photographs of all patients. Final scar appearance was evaluated using the Patient and Observer Scar Assessment Scale (POSAS). All patients had ruptured ECs, while 6 patients also had cellulitis of the surrounding tissues. All defects, after complete excision of ECs and debridement of surrounding unhealthy tissues, were successfully covered with KDPIF. The mean ‘tension-change’ at the defect and donor sites was −4.73 ± 0.21 N and −4.88 ± 0.25 N, respectively (p < 0.001). The mean ‘rate of tension-change’ at the defect and donor sites was −69.48 ± 1.7% and −71.16 ± 1.33%, respectively (p < 0.001). All flaps survived with no postoperative complications. The mean observer scar assessment scale (OSAS) summary score and patient scar assessment scale (PSAS) total score were 14.467 ± 5.069 and 15.6 ± 6.512, respectively. Overall, we suggest that KDPIF reconstruction is a good surgical modality for the management of complicated ECs on the back.
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Elia J, Hassidim A, Billig A, Chapchay K, Wu CT, Hung SY, Cheong DCF, Tsao CK. Objective and quantifiable measuring mechanism for assessing flap pliability: Our experience with 92 patients. Head Neck 2019; 41:3348-3355. [PMID: 31283090 DOI: 10.1002/hed.25851] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Revised: 04/19/2019] [Accepted: 06/14/2019] [Indexed: 11/07/2022] Open
Abstract
BACKGROUND Pliability describes a flaps' ability to bend under spatial limitations, yet a quantifiable measurement for this flexibility does not exist. METHODS Between January 2015 and January 2017, we applied a novel measuring mechanism to two free flaps for head and neck reconstruction. We allocated a flap pliability score (FPS) to these flaps and observed correlations to common variables. RESULTS Forty profunda artery perforator (PAP) and 52 anterolateral thigh (ALT) flaps were allotted a score depending on how pliable they performed on our test. Proximal PAP and distal ALT were more pliable than their respective opposite ends. Other interesting conclusions regarding these flaps were also made. CONCLUSIONS With our technique, pliability of the proximal and distal ends of PAP and ALT flaps was ascertained. Herein, we describe an innovative measuring mechanism via which we can allocate a FPS to any flap and thus obtain information regarding how suitable they are for a given recipient site.
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Affiliation(s)
- Jhonatan Elia
- Department of Plastic and Reconstructive Surgery, Chang Gung Memorial Hospital, Chang Gung Medical College, Chang Gung University, Taipei, Taiwan
| | - Ayal Hassidim
- Department of Plastic and Reconstructive Surgery, Hadassah Hebrew University Medical Center, Jerusalem, Israel
| | - Allan Billig
- Department of Plastic and Reconstructive Surgery, Hadassah Hebrew University Medical Center, Jerusalem, Israel
| | - Katya Chapchay
- Department of Plastic and Reconstructive Surgery, Hadassah Hebrew University Medical Center, Jerusalem, Israel
| | - Chieh-Tsai Wu
- Department of Neurosurgery, Chang Gung Memorial Hospital at Linkou, Chang Gung University, Taoyuan, Taiwan
| | - Shao-Yu Hung
- Department of Plastic and Reconstructive Surgery, Chang Gung Memorial Hospital, Chang Gung Medical College, Chang Gung University, Taipei, Taiwan
| | - David Chon-Fok Cheong
- Department of Plastic and Reconstructive Surgery, Chang Gung Memorial Hospital, Chang Gung Medical College, Chang Gung University, Taipei, Taiwan
| | - Chung-Kan Tsao
- Department of Plastic and Reconstructive Surgery, Chang Gung Memorial Hospital, Chang Gung Medical College, Chang Gung University, Taipei, Taiwan.,Center for Tissue Engineering, Chang Gung Memorial Hospital, Taoyuan, Taiwan
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Sommers MS, Regueira Y, Tiller DA, Everett JS, Brown K, Brignone E, Fargo JD. Understanding rates of genital-anal injury: Role of skin color and skin biomechanics. J Forensic Leg Med 2019; 66:120-128. [PMID: 31299484 DOI: 10.1016/j.jflm.2019.06.019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2018] [Revised: 06/28/2019] [Accepted: 06/30/2019] [Indexed: 11/26/2022]
Abstract
PURPOSE A series of studies suggest that non-Hispanic White women have significantly more injuries than non-Hispanic Black women after sexual assault and consensual sexual intercourse. One explanation for this difference is that the degree of skin protection may vary as skin mechanics and skin pigmentation vary. The aim of the study was to determine the association among genital-anal injury, skin color, skin viscoelasticity and skin hydration in women following consensual sexual intercourse when controlling for age, smoking history, body mass index (BMI), sun exposure, and health status. PROCEDURES We employed a prospective cohort study design to enroll women 21 years of age or older at two study sites. They underwent two data collection sessions, baseline and follow-up after consensual sexual intercourse. Baseline genital-anal injury identification occurred with a standard forensic examination (direct visualization, nuclear staining with toluidine blue contrast, and colposcopy examination) and measurements of other variables (skin color, skin viscoelasticity, skin hydration, age, smoking history, body mass index [BMI], sun exposure, and health status). Participants were then asked to have consensual sexual intercourse with a male partner of their choice and to return for a second forensic examination for injury detection. Genital-anal injury was regressed on skin color, skin viscoelasticity, skin hydration, age, smoking history, BMI, sun exposure, and health status. FINDINGS We enrolled 341 participants, 88 non-Hispanic White (25.8%), 54 non-Hispanic Black (15.8%), 190 Hispanic/Latina (55.7), and 9 Other Identities (2.6%). At baseline the genital-anal injury prevalence was 57.77% and at follow-up after consensual sexual intercourse, injury prevalence was 72.73%. External genital injury prevalence was associated with increased L* (lightness) values (Adjusted Odds Ratio [AOR] = 1.98, 95% Confidence Interval [CI] = 1.03, 4.04) and decreased skin elasticity (AOR = 0.96, 95% CI = 0.93, 0.99) at baseline. Increased skin hydration was associated with a significantly higher frequency of external, internal, anal, and total genital-anal injuries (Adjusted Rate Ratio [ARR] > 1.27) at follow-up. Also at the follow-up examination, Hispanic/Latina participants had significantly lower external genital and total genital-anal injury prevalence and frequency as compared to non-Hispanic White participants (AOR < 0.40). CONCLUSIONS Our findings provide qualified support for the importance of skin color during the forensic examination. Women with lighter skin tones may have skin that is more easily injured than women with darker tones. In contrast, external genital injuries may be more easily identified in women with light as compared to dark skin, a situation that is important in both the health care and criminal justice systems. Additionally, women with decreased viscoelasticity and increased hydration may be more easily injured. These findings support the need to develop forensic procedures that are effective in people across the range of skin colors and to interpret forensic findings considering the innate properties of the skin.
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Affiliation(s)
- Marilyn S Sommers
- University of Pennsylvania School of Nursing, 418 Curie Boulevard, Fagin Hall, Philadelphia, PA, 19104, USA.
| | - Yadira Regueira
- University of Puerto Rico School of Nursing, Medical Sciences Campus, Box 365067, San Juan, PR, 00936, USA.
| | - Deborah A Tiller
- University of Pennsylvania School of Nursing, 418 Curie Boulevard, Fagin Hall, Philadelphia, PA, 19104, USA.
| | - Janine S Everett
- Franklin and Marshall College, 415 Harrisburg Avenue, Lancaster, PA, 17603, USA.
| | - Kathleen Brown
- University of Pennsylvania, Fagin Hall, 418 Curie Boulevard, Philadelphia, PA, 19104, USA.
| | - Emily Brignone
- Utah State University, Department of Psychology, 2810 Old Main Hill, Logan, UT, 84322, USA.
| | - Jamison D Fargo
- Utah State University Department of Psychology, 2810 Old Main Hill, Logan, UT, 84341, USA.
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Pan W, Roccabianca S, Basson MD, Bush TR. Influences of sodium and glycosaminoglycans on skin oedema and the potential for ulceration: a finite-element approach. ROYAL SOCIETY OPEN SCIENCE 2019; 6:182076. [PMID: 31417698 PMCID: PMC6689624 DOI: 10.1098/rsos.182076] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Accepted: 06/03/2019] [Indexed: 06/10/2023]
Abstract
Venous ulcers are chronic transcutaneous wounds common in the lower legs. They are resistant to healing and have a 78% chance of recurrence within 2 years. It is commonly accepted that venous ulcers are caused by the insufficiency of the calf muscle pump, leading to blood pooling in the lower legs, resulting in inflammation, skin oedema, tissue necrosis and eventually skin ulceration. However, the detailed physiological events by which inflammation contributes to wound formation are poorly understood. We therefore sought to develop a model that simulated the inflammation, using it to determine the internal stresses and pressure on the skin that contribute to venous ulcer formation. A three-layer finite-element skin model (epidermis, dermis and hypodermis) was developed to explore the roles in wound formation of two inflammation identifiers: glycosaminoglycans (GAG) and sodium. A series of parametric studies showed that increased GAG and sodium content led to oedema and increased tissue stresses of 1.5 MPa, which was within the reported range of skin tissue ultimate tensile stress (0.1-40 MPa). These results suggested that both the oedema and increased fluid pressure could reach a threshold for tissue damage and eventual ulcer formation. The models presented here provide insights to the pathological events associated with venous insufficiency, including inflammation, oedema and skin ulceration.
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Affiliation(s)
- Wu Pan
- Department of Mechanical Engineering, Michigan State University, 428 South Shaw Lane, Room 2555, East Lansing, MI 48824, USA
| | - Sara Roccabianca
- Department of Mechanical Engineering, Michigan State University, 428 South Shaw Lane, Room 2555, East Lansing, MI 48824, USA
| | - Marc D. Basson
- Department of Surgery at the University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND, USA
| | - Tamara Reid Bush
- Department of Mechanical Engineering, Michigan State University, 428 South Shaw Lane, Room 2555, East Lansing, MI 48824, USA
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Smith SGVS, Yokich MK, Beaudette SM, Brown SHM, Bent LR. Effects of foot position on skin structural deformation. J Mech Behav Biomed Mater 2019; 95:240-248. [PMID: 31054375 DOI: 10.1016/j.jmbbm.2019.04.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Revised: 02/12/2019] [Accepted: 04/11/2019] [Indexed: 11/29/2022]
Abstract
As the largest and most superficial organ, the skin is well positioned for receiving sensory information from the environment. It is conceivable that changes in posture could result in deformations of the skin and subsequent changes in skin material properties. Specifically, the ankle and metatarsophalangeal joints have the capability to undergo large postural alterations with the potential to induce large structural deformations in the skin of the foot. The purpose of this study was to determine the extent to which alterations in foot posture may influence measures of foot sole and dorsum skin stretch, hardness, and thickness in vivo. Ten young and healthy individuals were tested while three static foot postures (plantar flexion, neutral and dorsiflexion) were maintained passively. Skin stretch deformation was quantified across each posture using an 11 × 4 point matrix of 3D kinematic markers affixed to the skin of the foot sole and dorsum. Skin hardness was assessed across each posture at specific locations of the foot sole (1st metatarsal, 5th metatarsal, medial arch, lateral arch and heel) and foot dorsum (proximal, middle and distal) using a handheld Shore durometer. Skin (epidermal + dermal) thickness was measured in each posture from the same test locations using ultrasound images obtained for the foot sole and dorsum. In the plantar flexion ankle posture, the foot sole skin was observed to relax/retract on average (± standard errorr of the mean (SEM) by 9 ± 2% to become both 20 ± 6% softer and 10 ± 6% thicker. In this posture, the foot dorsum skin stretched on average by 7 ± 2% resulting in 84 ± 8% harder and 5 ± 4% thinner skin. In the dorsiflexion ankle posture, the skin of the foot sole was observed to stretch on average by 5 ± 1% to become both 20 ± 8% harder and 4 ± 7% thinner. In this posture, the skin of the foot dorsum relaxed/retracted on average by 9 ± 1% resulting in the skin becoming 27 ± 12% softer and 7 ± 5% thicker. Notably, all of the sites responded with movement in a similar direction, but each site responded to a variable extent. Importantly, it was clear that the majority of skin structural deformation of the foot sole occurred within the 1st metatarsal, 5th metatarsal, and medial arch regions, while deformation was more evenly distributed across regions of the foot dorsum. The results suggest there is location specificity in the retraction and stretch characteristics of the foot skin. While not tested directly, this may suggest that local stretch distributions could be in part due to the underlying dermal and hypodermal structures in these foot regions. With these observed changes in the mechanical structure of the foot sole and dorsum skin tissue matrix, it is possible that corresponding posture-dependent changes in cutaneous mechanoreceptor activation may be present.
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Affiliation(s)
- Simone G V S Smith
- University of Guelph, Department of Human Health and Nutritional Science, Guelph, ON, Canada
| | - Maiya K Yokich
- University of Guelph, Department of Human Health and Nutritional Science, Guelph, ON, Canada
| | - Shawn M Beaudette
- University of Ottawa, School of Human Kinetics, Faculty of Health Sciences, Ottawa, ON, Canada
| | - Stephen H M Brown
- University of Guelph, Department of Human Health and Nutritional Science, Guelph, ON, Canada
| | - Leah R Bent
- University of Guelph, Department of Human Health and Nutritional Science, Guelph, ON, Canada.
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Cortés H, Mendoza-Muñoz N, Galván-Gil FA, Magaña JJ, Lima E, González-Torres M, Leyva-Gómez G. Comprehensive mapping of human body skin hydration: A pilot study. Skin Res Technol 2018; 25:187-193. [PMID: 30302824 DOI: 10.1111/srt.12633] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Accepted: 09/24/2018] [Indexed: 12/15/2022]
Abstract
BACKGROUND Previous studies analyzed a series of representative anatomical regions in the human body; however, there is a wide structural and cellular variability in the constitution of the skin. Our objective was to perform a comprehensive assessment of human skin hydration throughout the largest possible area. MATERIALS AND METHODS Hydration was registered by Corneometer® CM825 probe in 23 anatomical regions of five healthy men. Each zone was analyzed by 2-cm segments in the supine, prone, and lateral positions. A total of 7863 measurements were registered. RESULTS Differences in the degree of hydration among the prone, supine, and lateral regions were observed. The chest and back showed a pattern of increased hydration toward the neck area. Higher levels of hydration were evidenced in the proximal areas and in the regions near the elbow and knee. The regions of greater mechanical wear and with greater exposure to the sun exhibited a lower degree of hydration. CONCLUSION The human skin exhibited hydration patterns influenced by anatomical function and the degree of sun exposure. Detailed information of the hydration patterns could serve as reference for the design of topical products, as an indicator of their effectiveness, and for the monitoring of skin pathologies.
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Affiliation(s)
- Hernán Cortés
- Laboratorio de Medicina Genómica, Departamento de Genética, Instituto Nacional de Rehabilitación Luis Guillermo Ibarra Ibarra, México, México
| | | | - Francisco A Galván-Gil
- Departamento de Farmacia, Facultad de Química, Universidad Nacional Autónoma de México, Ciudad de México, México
| | - Jonathan J Magaña
- Laboratorio de Medicina Genómica, Departamento de Genética, Instituto Nacional de Rehabilitación Luis Guillermo Ibarra Ibarra, México, México
| | - Enrique Lima
- Laboratorio de Fisicoquímica y Reactividad de Superficies, Instituto de Investigaciones en Materiales, Universidad Nacional Autónoma de México, Ciudad de México, México
| | - Maykel González-Torres
- Escuela de Ingeniería y Ciencias, Instituto Tecnológico y de Estudios Superiores de Monterrey Campus Puebla, Puebla, México
| | - Gerardo Leyva-Gómez
- Departamento de Farmacia, Facultad de Química, Universidad Nacional Autónoma de México, Ciudad de México, México
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Frailty and body mass index are associated with biophysical properties of the skin in community-dwelling older adults. J Tissue Viability 2018; 27:141-145. [PMID: 29866626 DOI: 10.1016/j.jtv.2018.05.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Revised: 05/05/2018] [Accepted: 05/22/2018] [Indexed: 12/22/2022]
Abstract
AIM OF THE STUDY This study aimed to investigate the association of frailty and body mass index (BMI) with biophysical properties of the skin in community-dwelling older people. MATERIALS AND METHODS A cross-sectional study was conducted in a suburban Japanese city. Older adults aged ≥65 years and participating in a health checkup program were recruited (n = 128). Stratum corneum hydration, clinical manifestations of dry skin, skin elasticity and condition of the dermis (as measured by ultrasonography) were evaluated on the volar forearm. Frailty phenotype and BMI were also evaluated. RESULTS The mean age of participants was 74.5 years, and 96.1% were women. Skin thickness was significantly decreased in frail participants compared with non-frail participants in an age-adjusted multivariate model (p = 0.009). Frail participants showed significantly lower skin elasticity values than non-frail participants in a univariate analysis (p = 0.024), but this was not significant in the multivariate model. In participants with BMI ≥25 kg/m2, clinical manifestations of dry skin were significantly decreased compared with BMI <21.5 kg/m2 (p = 0.002). Participants with BMI ≥25 kg/m2 and with 21.5 ≤ BMI <25 kg/m2 showed significantly higher skin elasticity values than participants with BMI <21.5 kg/m2 (p = 0.014 and p = 0.042, respectively). CONCLUSION Frailty was associated with decreased skin thickness and decreased skin elasticity partially via the influence of chronological aging. Low body mass was associated with increased xerosis manifestations and decreased skin elasticity in community-dwelling older adults.
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White ZW, Vernerey FJ. Armours for soft bodies: how far can bioinspiration take us? BIOINSPIRATION & BIOMIMETICS 2018; 13:041004. [PMID: 29595522 DOI: 10.1088/1748-3190/aababa] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The development of armour is as old as the dawn of civilization. Early man looked to natural structures to harvest or replicate for protection, leaning on millennia of evolutionary developments in natural protection. Since the advent of more modern weaponry, Armor development has seemingly been driven more by materials research than bio-inspiration. However, parallels can still be drawn between modern bullet-protective armours and natural defensive structures. Soft armour for handgun and fragmentation threats can be likened to mammalian skin, and similarly, hard armour can be compared with exoskeletons and turtle shells. Via bio-inspiration, it may be possible to develop structures previously un-researched for ballistic protection. This review will cover current modern ballistic protective structures focusing on energy dissipation and absorption methods, and their natural analogues. As all armour is a compromise between weight, flexibility and protection, the imbricated structure of scaled skin will be presented as a better balance between these factors.
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Affiliation(s)
- Zachary W White
- Mechanical Engineering, University of Colorado Boulder, 427 UCB, Boulder, United States of America
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Virén T, Iivarinen JT, Sarin JK, Harvima I, Mayrovitz HN. Accuracy and reliability of a hand-held in vivo
skin indentation device to assess skin elasticity. Int J Cosmet Sci 2018; 40:134-140. [DOI: 10.1111/ics.12444] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Accepted: 12/30/2017] [Indexed: 11/29/2022]
Affiliation(s)
- T. Virén
- Department of Applied Physics; University of Eastern Finland; Kuopio Finland
- Cancer Center; Kuopio University Hospital; Kuopio Finland
| | - J. T. Iivarinen
- Department of Applied Physics; University of Eastern Finland; Kuopio Finland
| | - J. K. Sarin
- Department of Applied Physics; University of Eastern Finland; Kuopio Finland
| | - I. Harvima
- Department of Dermatology; University of Eastern Finland and Kuopio University Hospital; Kuopio Finland
| | - H. N. Mayrovitz
- Department of Physiology; College of Medical Sciences; Nova Southeastern University; Ft. Lauderdale Fl USA
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Zhang X. A noninvasive surface wave technique for measuring finger's skin stiffness. J Biomech 2018; 68:115-119. [PMID: 29279194 DOI: 10.1016/j.jbiomech.2017.12.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Revised: 11/21/2017] [Accepted: 12/10/2017] [Indexed: 01/03/2023]
Abstract
The purpose of this work was to develop a compact surface wave elastography (CSWE) device for measuring finger's skin stiffness. The motivation was to develop a noninvasive technique for assessing limited cutaneous systemic sclerosis (lcSSc) in accordance with new ACR/EULAR clarification criteria. Currently, the Modified Rodnan Skin Score (MRSS) is widely used for assessing systemic sclerosis but is challenging for assessing patients with lcSSc. The novelty of CSWE is to develop a noninvasive technique to measure the elastic properties of skin of fingers. In the CSWE device, a local harmonic vibration was generated on the finger's skin. The surface wave speed on the finger's skin was measured without contact using a compact optical probe. The CSWE device was first validated with an ultrasound-based surface wave elastography (USWE) device on a phantom. The CSWE device was then validated with the USWE device on both the dorsal and ventral arms of a volunteer. The CSWE device was evaluated to measure the surface wave speed of four fingers for the volunteer. The CSWE device may be useful for measuring skin stiffness over multiple areas of fingers and hands for assessing lcSSc.
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Affiliation(s)
- Xiaoming Zhang
- Department of Radiology, Mayo Clinic, Rochester, MN 55905, USA.
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Sonenblum SE, Sprigle SH. Buttock tissue response to loading in men with spinal cord injury. PLoS One 2018; 13:e0191868. [PMID: 29415014 PMCID: PMC5802854 DOI: 10.1371/journal.pone.0191868] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Accepted: 01/13/2018] [Indexed: 11/18/2022] Open
Abstract
OBJECTIVE/BACKGROUND Despite the fact that most people with a spinal cord injury who use a wheelchair for mobility are considered at-risk for pressure ulcer (PrU) development, there still exists a spectrum of risk amongst this group. Efforts to differentiate risk level would benefit from clinical tools that can measure or predict the buttocks response to loading. Therefore, the goal of this study was to identify how tissue compliance and blood flow were impacted by clinically-measurable risk factors in young men with SCI. METHODS Blood flow at the ischial tuberosity was measured using laser Doppler flowmetry while the seated buttock was unloaded, and loaded at lower (40-60 mmHg) and high (>200 mmHg) loads. Tissue compliance of the buttock was measured using the Myotonometer while subject were lifted in a Guldmann Net. RESULTS Across 28 participants, blood flow was significantly reduced at high loads, while no consistent, significant changes were found at lower loads. At 40-60 mmHg, blood flow decreased in participants with a pressure ulcer history and lower BMI, but stayed the same or increased in most other participants. The buttock displaced an average of 9.3 mm (2.7 mm) at 4.2 N, which represented 82% (7%) of maximum displacement. BMI was related to the amount of buttock tissue displacement while smoking status explained some of the variation in the percent of max displacement. CONCLUSION Wide variability in tissue compliance and blood flow responses across a relatively homogeneous population indicate that differences in biomechanical risk may provide an explanation for the spectrum of PrU risk among persons with SCI.
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Affiliation(s)
- Sharon Eve Sonenblum
- George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia, United States of America
| | - Stephen H. Sprigle
- George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia, United States of America
- School of Industrial Design, Georgia Institute of Technology, Atlanta, Georgia, United States of America
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Kim MA, Kim EJ, Lee HK. Use of SkinFibrometer®to measure skin elasticity and its correlation with Cutometer®and DUB®Skinscanner. Skin Res Technol 2018; 24:466-471. [DOI: 10.1111/srt.12455] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/04/2018] [Indexed: 12/22/2022]
Affiliation(s)
- M. A. Kim
- Skincare Research InstituteAMOREPACIFIC R&D Center Yongin Korea
| | - E. J. Kim
- Skincare Research InstituteAMOREPACIFIC R&D Center Yongin Korea
| | - H. K. Lee
- Skincare Research InstituteAMOREPACIFIC R&D Center Yongin Korea
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Zhang X, Zhou B, Kalra S, Bartholmai B, Greenleaf J, Osborn T. An Ultrasound Surface Wave Technique for Assessing Skin and Lung Diseases. ULTRASOUND IN MEDICINE & BIOLOGY 2018; 44:321-331. [PMID: 29195756 PMCID: PMC5743597 DOI: 10.1016/j.ultrasmedbio.2017.10.010] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Revised: 09/28/2017] [Accepted: 10/19/2017] [Indexed: 05/14/2023]
Abstract
Systemic sclerosis (SSc) is a multi-organ connective tissue disease characterized by immune dysregulation and organ fibrosis. Severe organ involvement, especially of the skin and lung, is the cause of morbidity and mortality in SSc. Interstitial lung disease (ILD) includes multiple lung disorders in which the lung tissue is fibrotic and stiffened. The purpose of this study was to translate ultrasound surface wave elastography (USWE) for assessing patients with SSc and/or ILD via measuring surface wave speeds of both skin and superficial lung tissue. Forty-one patients with both SSc and ILD and 30 healthy patients were enrolled in this study. An external harmonic vibration was used to generate the wave propagation on the skin or lung. Three excitation frequencies of 100, 150 and 200 Hz were used. An ultrasound probe was used to measure the wave propagation in the tissue non-invasively. Surface wave speeds were measured on the forearm and upper arm of both left and right arm, as well as the upper and lower lungs, through six intercostal spaces of patients and healthy patients. Viscoelasticity of the skin was calculated by the wave speed dispersion with frequency using the Voigt model. The magnitudes of surface wave speed and viscoelasticity of patients' skin were significantly higher than those of healthy patients (p <0.0001) for each location and each frequency. The surface wave speeds of patients' lung were significantly higher than those of healthy patients (p <0.0001) for each location and each frequency. USWE is a non-invasive and non-ionizing technique for measuring both skin and lung surface wave speed and may be useful for quantitative assessment of SSc and/or ILD.
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Affiliation(s)
- Xiaoming Zhang
- Department of Radiology, Mayo Clinic, Rochester, Minnesota, USA; Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota, USA.
| | - Boran Zhou
- Department of Radiology, Mayo Clinic, Rochester, Minnesota, USA
| | - Sanjay Kalra
- Department of Pulmonary and Critical Care Medicine, Mayo Clinic, Rochester, Minnesota, USA
| | | | - James Greenleaf
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota, USA
| | - Thomas Osborn
- Department of Rheumatology, Mayo Clinic, Rochester, Minnesota, USA
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Sanchez A, Mills C, Haake S, Norris M, Scurr J. Quantification of gravity-induced skin strain across the breast surface. Clin Biomech (Bristol, Avon) 2017; 50:47-55. [PMID: 28987871 DOI: 10.1016/j.clinbiomech.2017.10.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Revised: 09/07/2017] [Accepted: 10/02/2017] [Indexed: 02/07/2023]
Abstract
BACKGROUND Quantification of the magnitude of skin strain in different regions of the breast may help to estimate possible gravity-induced damage whilst also being able to inform the selection of incision locations during breast surgery. The aim of this study was to quantify static skin strain over the breast surface and to estimate the risk of skin damage caused by gravitational loading. METHODS Fourteen participants had 21 markers applied to their torso and left breast. The non-gravity breast position was estimated as the mid-point of the breast positions in water and soybean oil (higher and lower density than breast respectively). The static gravity-loaded breast position was also measured. Skin strain was calculated as the percentage extension between adjacent breast markers in the gravity and non-gravity loaded conditions. FINDINGS Gravity induced breast deformation caused peak strains ranging from 14 to 75% across participants, with potentially damaging skin strain (>60%) in one participant and skin strains above 30% (skin resistance zone) in a further four participants. These peak strain values all occurred in the longitudinal direction in the upper region of the breast skin. In the latitudinal direction, smaller-breasted participants experienced greater strain on the outer (lateral) breast regions and less strain on the inner (medial) breast regions, a trend which was reversed in the larger breasted participants (above size 34D). INTERPRETATION To reduce tension on surgical incisions it is suggested that preference should be given to medial latitudinal locations for smaller breasted women and lateral latitudinal locations for larger breasted women.
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Affiliation(s)
- Amy Sanchez
- Department of Sport and Exercise Science, Spinnaker Building, University of Portsmouth, PO1 2ER, UK
| | - Chris Mills
- Department of Sport and Exercise Science, Spinnaker Building, University of Portsmouth, PO1 2ER, UK.
| | - Steve Haake
- Centre for Sports Engineering Research, Sheffield Hallam University, Sheffield S10 2BP, UK
| | - Michelle Norris
- Department of Sport and Exercise Science, Spinnaker Building, University of Portsmouth, PO1 2ER, UK
| | - Joanna Scurr
- Department of Sport and Exercise Science, Spinnaker Building, University of Portsmouth, PO1 2ER, UK
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Location-specific mechanical response and morphology of facial soft tissues. J Mech Behav Biomed Mater 2017; 78:108-115. [PMID: 29149656 DOI: 10.1016/j.jmbbm.2017.10.021] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Accepted: 10/16/2017] [Indexed: 11/21/2022]
Abstract
The facial tissue of 9 healthy volunteers (m/f; age: 23-60y) is characterized at three different locations using a procedure combining suction measurements and 18MHz ultrasound imaging. The time-dependent and multilayered nature of skin is accounted for by adopting multiple loading protocols which differ with respect to suction probe opening size and rate of tissue deformation. Over 700 suction measurements were conducted and analyzed according to location-specific mechanical and morphological characteristics. All corresponding data are reported and made available for facial tissue analysis and biomechanical modeling. Higher skin stiffness is measured at the forehead in comparison to jaw and parotid; these two regions are further characterized by lower creep deformation. Thicker tissue regions display a tendency towards a more compliant and less dissipative response. Comparison of superficial layer thickness and corresponding mechanical measurements suggests that connective tissue density determines the resistance to deformation in suction experiments.
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Effects of Autologous Fat and ASCs on Swine Hypertrophic Burn Scars: A Multimodal Quantitative Analysis. PLASTIC AND RECONSTRUCTIVE SURGERY-GLOBAL OPEN 2017; 5:e1547. [PMID: 29263956 PMCID: PMC5732662 DOI: 10.1097/gox.0000000000001547] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Accepted: 09/08/2017] [Indexed: 12/14/2022]
Abstract
Background: Hypertrophic scar formation is unpredictable and poorly understood, afflicting both the pediatric and adult populations. Treatment methods with conservative and invasive approaches have low rates of compliance and high rates of morbidity. The purpose of this study was to test a reproducible scar model and investigate a new technique of scar modification through the use of adipose- derived progenitor stromal cells (ASCs). Methods: Twenty thermal deep-partial thickness contact burns were created on the dorsum of three 8-week-old domestic swine and allowed to mature for 10 weeks. Scars were then injected with 2 cc saline, expanded autologous ASCs, or 2 cc fresh lipoaspirate and sampled at 2 week intervals up to 10 weeks postinjection. Volumetric analysis with a 3-D scanner, mechanical elasticity testing through negative pressure transduction, and standardized photography evaluation with Image J was performed. RNA sequencing was performed on scar tissue samples, cultured cells, and fresh lipoaspirate to determine relevant gene transcription regulation. Immunohistochemistry was used to verify expression level changes within the scars. Results: Volumetric analysis demonstrates a reduction in average scar thickness at 6 weeks when injected with ASCs (−1.6 cc3) and autologous fat (−1.95 cc3) relative to controls (−0.121 cc3; P < 0.05). A decrease in overall tissue compliance is observed with fat or ASC injection when compared with unburned skin at 8 weeks (35.99/37.94 versus 49.36 mm Hg × mm; P < 0.01). RNA sequencing demonstrates altered regulation of fibroblast gene expression and a decreased inflammatory profile when scars are injected with autologous fat/ASCs over controls. Conclusion: Early results suggest that autologous fat and/or ASCs may improve healing of hypertrophic scarring by altering the cellular and structural components during wound remodeling up to 20 weeks after injury. This may have beneficial applications in early treatment of large or cosmetically sensitive immature burn scars.
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Han SH, Park JW. Diabetic and sympathetic influences on the water permeability barrier function of human skin as measured using transepidermal water loss: A case-control study. Medicine (Baltimore) 2017; 96:e8611. [PMID: 29137090 PMCID: PMC5690783 DOI: 10.1097/md.0000000000008611] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The presence of long-standing hyperglycemic conditions has been suggested to lead to many skin problems associated with an impaired skin barrier function. However, the relationship between impaired skin barrier status and altered peripheral nervous system function has not yet been determined. The purpose of this study was to investigate the water evaporation rate as a measure of the permeability barrier function of diabetic skin and its relationship to diabetic sensorimotor polyneuropathy (DSPN) and peripheral autonomic neuropathy (PAN) using well-controlled confounding variables.This case-control study included 42 participants with chronic diabetes and 43 matched healthy controls. The diabetic group underwent a nerve conduction study and sympathetic skin response (SSR) test to confirm the presence of DSPN and PAN, respectively. Different skin regions were analyzed using the noninvasive Tewameter instrument (Courage + Khazaka Electronic GmbH, Cologne, Germany). The impacts of PAN, DSPN, age, and diabetes duration on the values of transepidermal water loss (TEWL) were each analyzed and compared between the groups.Regardless of the presence of DSPN or PAN, the TEWL values as measured on the distal extremities were significantly lower in the diabetic group than in the control group. In the diabetic group, participants with abnormal SSR test results showed decreased TEWL values in the finger, sole, and first toe, as compared with participants with normal SSR test results. In the control group, age showed a negative correlation with the TEWL values with respect to some measured regions. However, in the diabetic group, there was no significant correlation between either patient age or diabetes duration and TEWL values.The presence of a long-term hyperglycemic state can reduce the permeability barrier function of the skin, a phenomenon that might be related to the presence of an impaired peripheral sympathetic nervous system, rather than peripheral sensorimotor denervation.
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Affiliation(s)
- Seung Hoon Han
- Department of Rehabilitation Medicine, Hanyang University Guri Hospital, Hanyang University College of Medicine, Hanyang, Gyeonggi-do, Republic of Korea
| | - Ji Woong Park
- Department of Physical Medicine and Rehabilitation, Soonchunhyang University Seoul Hospital, Soonchunhyang University College of Medicine, Seoul
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