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Benign Neoplasms
Published in Ayşe Serap Karadağ, Lawrence Charles Parish, Jordan V. Wang, Roxburgh's Common Skin Diseases, 2022
Abdullah Demirbaş, Ömer Faruk Elmas, Necmettin Akdeniz
Examples of clinical variants include the following: Dermatosis papulosa nigra: This is a clinically different entity but is considered a variant of seborrheic keratosis. The lesion is seen in a darker-skinned patient, more common in women. It is characterized by numerous pigmented papules on the face, neck, and trunk.Stucco keratosis: This represent a smaller variant of seborrheic keratoses and has a light tan to gray color with multiple lesions and symmetric distribution, especially on the calves and may be somewhat flat.Inverted follicular keratosis: The lesion often appears as solitary nonpigmented verrucous papule on the face. This is considered by some to be an endophytic variant of inflamed seborrheic keratosis, which originates from the follicular infundibulum. Histology is generally needed for diagnosis and confirmation.Laboratory studies: Various histologic types of seborrheic keratoses have been described. Oftentimes, more than one can be present in the same lesion. Low molecular weight cytokeratin, filaggrin, and BCL-2 expression can be seen, which may vary based on histologic subtype; however, a common finding is Borst-Jadassohn phenomenon.
Skeletal muscle biopsy
Published in R. C. Richard Davison, Paul M. Smith, James Hopker, Michael J. Price, Florentina Hettinga, Garry Tew, Lindsay Bottoms, Sport and Exercise Physiology Testing Guidelines: Volume II – Exercise and Clinical Testing, 2022
Richard A. Ferguson, Natalie F. Shur
The preparation of tissue for histology/histochemical analysis requires preservation of tissue architecture and cell morphology; therefore, prompt and adequate embedding and/or fixation is essential. The three main methods of embedding tissue for sectioning are paraffin wax, optimal cutting temperature (OCT) compound (e.g., Tissue-Tek ™) and resin, each with its own benefits and weaknesses. Excess blood, fat and connective tissue are removed prior to mounting, in most cases with OCT, on either cork or an appropriate mould. This is carefully but rapidly frozen in liquid nitrogen-cooled isopentane, which prevents the formation of ice crystals, and subsequently stored at − 80°C until analysis.
Skeletal muscle biopsy
Published in R. C. Richard Davison, Paul M. Smith, James Hopker, Michael J. Price, Florentina Hettinga, Garry Tew, Lindsay Bottoms, Sport and Exercise Physiology Testing Guidelines: Volume I – Sport Testing, 2022
Richard A. Ferguson, Natalie F. Shur
The preparation of tissue for histology/histochemical analysis requires preservation of tissue architecture and cell morphology; therefore, prompt and adequate embedding and/or fixation is essential. The three main methods of embedding tissue for sectioning are paraffin wax, optimal cutting temperature (OCT) compound (e.g., Tissue-Tek) and resin, each with their own benefits and weaknesses. One removes excess blood, fat and connective tissue prior to mounting, in most cases with OCT, on either cork or an appropriate mould. This is carefully but rapidly frozen in liquid nitrogen–cooled isopentane, which prevents the formation of ice crystals, and subsequently stored at −80°C until analysis.
Prevention and treatment of burn wound infections: the role of topical antimicrobials
Published in Expert Review of Anti-infective Therapy, 2022
Deepak K. Ozhathil, Steven E. Wolf
Comment: Silver nitrate is one of the oldest antimicro bial solutions used in burn care. It has limited gram-positive coverage (Staphylococcus species), good bacteriostatic effect against aerobic gram-negative species (Pseudomonas aeruginosa and Escherichia coli), and some yeast; however, it is not effective against Klebsiella, Providencia, Enterobacter and most fungi. For this reason, it is typically administered concomitantly with Nystatin at many burn centers. It is not painful, readily available and affordable. Historically considered to be non-cytotoxic at a concentration of 0.5%, le Duc and colleagues compared the cytotoxic effect of twelve topical antimicrobial agents on traditionally harvested autograft as well as autologous human skin substitute (HSS) made from cultured fibroblast populated on donor dermis tissue. Cytotoxicity was assessed in three ways. Histology was performed to assess structural changes in the tissue architecture. Keratinocyte RNA and mitochondrial metabolism were measured as surrogates for cellular activity. Silver nitrate was noted to have a mild negative effect on cellular metabolism on autologous HSS and a no impact on traditional autograft [37]. This suggests that there may be a subclinical degree of cytotoxicity of which to be aware.
Single-cell RNA sequencing: An overview for the ophthalmologist
Published in Seminars in Ophthalmology, 2021
Elizabeth J. Rossin, Lucia Sobrin, Leo A. Kim
Traditionally, marker genes and proteins are used to assign cell types in a tissue sample. One of the most longstanding and reliable approaches is histology, whereby tissue samples are stained for proteins or molecules that are known to characterize particular cells. Histology is highly unique in its ability to resolve cell type and spatial structure simultaneously, and it will likely never find itself antiquated. RNA sequencing is an example of a technique that does not maintain information of tissue architecture. Yet, histology is limited in terms of its ability to narrowly characterize individual cells because usually only a handful of stains are employed. Function is one way that cell type can be distinguished while preserving architecture. This is particularly useful when studying neuronal tissues, such as the exquisite characterization of retinal layers described by Masland et al. in 20123. However, the study of the function is limited by the particular assay at hand, and only certain functional readouts can be measured.
In vivo percutaneous permeation of gold nanomaterials in consumer cosmetics: implication in dermal safety assessment of consumer nanoproducts
Published in Nanotoxicology, 2021
Mingjing Cao, Bai Li, Mengyu Guo, Ying Liu, Lili Zhang, Yaling Wang, Bin Hu, Jiayang Li, Duncan S. Sutherland, Liming Wang, Chunying Chen
HE staining is a popular and established method in histology. Herein it was used to evaluate the dermal lesions caused by exposure of cosmetic creams and extracted Au nanosheets. 4 μm serial paraffin sections sliced carefully from skin surface to subcutaneous layer were deparaffinized, rehydrated, and stained with hematoxylin and eosin. For IHC analysis, 4 μm serial sections were firstly deparaffinized and rehydrated, followed by retrieving the masked antigens with 0.01 M sodium citrate buffer in the microwave (96 °C for 10 min). After blocking endogenous peroxidase with 30% H2O2, the sections were incubated with primary antibodies overnight at 4 °C and followed by the incubation with secondary antibodies labeled by horseradish peroxidase (HRP) at 37 °C for 1 h. Hematoxylin was used for nuclei staining.