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Anatomy, physiology, and histology of the skin
Published in Michael Parker, Charlie James, Fundamentals for Cosmetic Practice, 2022
This is the squamous cell layer and is approximately 5–10 cells thick. It has a characteristic microscopic appearance of spiny cellular bodies created by shrinkage of the desmosomes which bind epithelial cells together. The stratum spinosum plays a key role in the strength and flexibility of the skin.
Anatomy of the Midface
Published in Neil S. Sadick, Illustrated Manual of Injectable Fillers, 2020
Stephen A. Goldstein, Evan Ransom
The epidermis is a continually renewing keratinizing squamous epithelium, composed of four layers or strata. Beginning at the deepest layer, just above the dermal–epidermal junction, is the stratum germinativum. This basal layer is composed of columnar-shaped keratinocytes, which are attached to a basement membrane and which divide and give rise to more superficial layers. Interspersed at this level are the melanocytes, which are responsible for pigment production. Immediately above lies the stratum spinosum, which is several cells thick and contains keratinocytes that have detached from the basal layer. Next is the thinner stratum granulosum, typically one to four cells thick and darker in appearance. The most superficial is the stratum corneum, which consists of keratinocytes that have shed their nuclei and flattened to form keratin plates. As these cells are sloughed they are replaced from below.
Exploring the Plant Kingdom for Sources of Skincare Cosmeceuticals
Published in Mahendra Rai, Shandesh Bhattarai, Chistiane M. Feitosa, Wild Plants, 2020
Mayuri Napagoda, Sanjeeva Witharana
The skin is the outer covering of the human body and is considered as the largest organ in a human. It is comprised of three major structural layers viz., epidermis, dermis, and hypodermis (Tabassum and Hamdani 2014). The epidermis is the outermost layer of the skin which encompasses five sub-layers/strata; stratum corneum, stratum lucidum, stratum granulosum, stratum spinosum, and stratum basale. The dermis lies beneath the epidermis and is attached to an underlying hypodermis or subcutaneous connective tissue (Tabassum and Hamdani 2014).
LncRNA MALAT-1 regulates the growth of interleukin-22-stimulated keratinocytes via the miR-330-5p/S100A7 axis
Published in Autoimmunity, 2022
Yu Zhou, Xiaohong Li, Yaju Duan, Yong Luo, Shuling Tang, Jian Wang
Psoriasis is a chronic autoimmune disease that not only affects the skin but also damages the body’s joints with systemic manifestations and a significant negative impact on patients’ quality of life [1]. Patients with psoriasis are at high risk for developing comorbidities, such as depression, metabolic syndrome, diabetes, and cardiovascular diseases [2]. Manifold internal and external factors, including environmental factors, susceptibility genes, keratinocytes, and the immune system, may be related to psoriasis pathogenesis [3]. However, the pathogenetic mechanisms of psoriasis are still elusive. Histologically, the features of psoriasis-like dermatitis include psoriasiform hyperplasia, loss of granular layer, parakeratosis, and thickening of stratum spinosum, which are also accompanied by infiltrations of inflammatory cells into the epidermis and dermis [1,4]. Thus, investigations of keratinocyte hyperproliferation may contribute to developing therapeutic strategies for psoriasis.
Dermato-pharmacokinetic: assessment tools for topically applied dosage forms
Published in Expert Opinion on Drug Delivery, 2021
Vamshi Krishna Rapalli, Gautam Singhvi
Skin is the outermost largest organ in the body. It protects the body from physical, chemical, and microbial assaults and also prevents water loss from the body. The skin comprises three layers, i.e. epidermis, dermis, and subcutaneous tissue. Epidermis is made up of five layers composed of stratum corneum, stratum lucidum, stratum granulosum, stratum spinosum, and stratum basale. The stratum corneum is the outermost layer and comprise dead keratinocytes, and lamellar granules. The corneocytes and lipids form tight junctions in the stratum corneum like brick and mortar. Stratum corneum acts as a permeation and diffusional barrier for topically applied dosage form for skin disorders and transdermal drug delivery. The topical formulations are considered as a mainstay for the treatment of these skin disorders. Topical drug delivery systems are mostly preferred to deliver the drugs to the target site with minimal systemic adverse effects.
Prophylactically applied Hydrofilm polyurethane film dressings reduce radiation dermatitis in adjuvant radiation therapy of breast cancer patients
Published in Acta Oncologica, 2018
Leonard Christopher Schmeel, David Koch, Sabina Stumpf, Christina Leitzen, Birgit Simon, Heinrich Schüller, Susanne Vornholt, Felix Schoroth, Thomas Müdder, Fred Röhner, Stephan Garbe, Frederic Carsten Schmeel, Hans Heinz Schild, Timo Martin Wilhelm-Buchstab
Side reactions were minor and, in all cases, self-limiting without additional therapy; most of these were caused by shear stress at the edges of sub-optimally attached film dressings. Accordingly, these adverse reactions appeared within 24 h following the attachment of Hydrofilm dressings, and required appropriate film dressing replacement. Due to the patient’s individual anatomy, for example, because of varying skin folds, a smooth and shear stress-free application was not always possible and mostly there was no obvious shear stress discernible to the radiation therapist in these cases. The strata of skin around the stratum spinosum are most susceptible to shear, particularly in already damaged skin. When the stratum spinosum separates from the connecting tissues below, plasma diffuses out and eventually forms blisters [37]. Such shear-stress induced blisters represent the most serious side effect observed; they were seen in four women accounting for approximately 7% (4/56) of the patient cohort. Except for localized allergic or not-specified intolerance reactions, which were present in 8.1% (5/62) of patients, adverse reactions might have been avoided by an appropriate Hydrofilm application, especially in the final phase of radiation therapy when radiation-induced skin damage is already advanced and the skin is, therefore, more susceptible to shear. However, in a clinical routine setting, the use of larger-scaled dressings could possibly shift the shear-forces at the film dressing edges to fully intact skin areas next to the treatment area and thereby avoid or at least reduce the observed reactions.