ABSTRACT
OBJECTIVE: To examine the epidermis in induced phytophotodermatitis using transmission electron microscopy in order to detect histologic changes even before lesions are visible by light microscopy. INTRODUCTION: In the first six hours after the experimental induction of phytophotodermatitis, no changes are detectable by light microscopy. Only after 24 hours can keratinocyte necrosis and epidermal vacuolization be detected histologically, and blisters form by 48 hours. METHODS: The dorsum of four adult rats (Rattus norvegicus) was manually epilated. After painting the right half of the rat with the peel juice of Tahiti lemon, they were exposed to sunlight for eight minutes under general anesthesia. The left side was used as the control and exposed to sunlight only. Biopsies were performed immediately after photoinduction and one and two hours later, and the tissue was analyzed by transmission electron microscopy. RESULTS: No histological changes were seen on the control side. Immediately after induction, vacuolization in keratinocytes was observed. After one hour, desmosomal changes were also observed in addition to vacuolization. Keratin filaments were not attached to the desmosomal plaque. Free desmosomes and membrane ruptures were also seen. At two hours after induction, similar changes were found, and granular degeneration of keratin was also observed. DISCUSSION: The interaction of sunlight and psoralens generates a photoproduct that damages keratinocyte proteins, leading to keratinocyte necrosis and blister formation. CONCLUSIONS: Transmission electron microscopy can detect vacuolization, lesions of the membrane, and desmosomes in the first two hours after experimental induction of phytophotodermatitis.
Subject(s)
Animals , Rats , Dermatitis, Phototoxic/pathology , Desmosomes/ultrastructure , Epidermis/ultrastructure , Microscopy, Electron, Transmission/standards , Blister/chemically induced , Blister/pathology , Citrus , Disease Models, Animal , Erythema/chemically induced , Erythema/pathology , Fruit , Necrosis/chemically induced , Necrosis/pathologyABSTRACT
Lichen planus [L.P] is an idiopathic inflammatory disease of the skin and mucous membrane. Desmosomes are responsible for the adhesion of keratinocytes. Tonofilaments are one of the major cytoskeleton structure in mammalian epidermis. Six patients complained from Lichen planus are included in this study for the study of ultrastructure of both desmosomes and tonofilaments. Revealed an increase in the size and numbers of both of them which can be explained as a one of the defensive mechanism of the cells against frequent rubbing which accompanied L.P. which is considered as a resistance mechanism of keratinocytes
Subject(s)
Humans , Microscopy, Electron , Desmosomes/ultrastructure , Keratinocytes , Intermediate Filaments , Biopsy , Lichen Planus/pathologySubject(s)
Humans , Desmosomes/physiology , Intercellular Junctions/physiology , Keratinocytes/ultrastructure , Desmosomes/chemistry , Desmosomes/ultrastructure , Immunoglobulins/chemistry , Integrins/chemistry , Integrins/physiology , Intercellular Junctions/physiology , Keratinocytes/chemistry , Cell Adhesion Molecules/physiology , Pemphigoid, Bullous , Self-Evaluation ProgramsABSTRACT
En este trabajo se describe la caracterización morfológica, cromosómica y presencia de desmosomas de una línea celular (CaLo) derivada de una biopsia de cáncer cervicouterino. Nuestros resultados indican que CaLo posee una morfología típica de células epiteliales, una aneuploidia cromosómica con número modal de 58 y presencia de desmosomas de bida a la positividad en membrana para la presencia de desmogleína-1. A partir de CaLo también se aisló un clon llamado KaLo. esta clonación nos proporciona una evidencia del origen maligno de estas células. Ambos tipos celulares fueron cultivados en presencia de algunas citocinas recientemente empleadas en ciertos protocolos clínicos (TNF-Ó, IL-2. IL-3 GM-CSF, M-CSF e IFN-ç). Nuestros resultados demuestran un efecto inhibidor de la proliferación por parte de TNF-Ó, IL-3 y GM-CSF, mientras que con M-CSF e IFN-ç no se detectó efecto. Por otra parte, obresvamos un incremento en la proliferación celular en presencia de la IL-2. Estos resultados dan indicios de que el TNF-Ó, la IL-3 y el M-CSF pueden tener posibilidades de aplicación clínica por sus propiedades inhibidoras; mientras que ponen en evidencia el riesgo de utilizar in vivo la IL-2, pues activa la proliferación de células tumorales de cérvix, tal como se ha informado para algunos carcinomas de cabeza y cuello