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Horny Layer (horny + layer)

Distribution by Scientific Domains

Medical Sciences	83%

Selected Abstracts

Ultrastructure of pitted keratolysis

INTERNATIONAL JOURNAL OF DERMATOLOGY, Issue 9 2000
Hiram L. De Almeida Jr MD
A 20-year-old man presented with pitted keratolysis (PK), demonstrating the typical crateriform pits on the hallux ( Fig. 1), ball of the foot, and on the interdigital surface. The involved keratin specimen was obtained by a shaving technique and processed for transmission (TEM) and scanning (SEM) electron microscopy. The patient, who wore only sports shoes, had hyperhidrosis plantaris. He was treated with topical erythromycin with good results. Bacterial cultures from the lesions showed Corynebacterium sp. Figure 1. Crateriform pits on the hallux TEM demonstrated filamentous coccoid bacteria in the keratin ( Fig. 2), showing transversal septations. Tunnel-like spaces were built inside the horny layer, where the bacteria showed a hairy surface ( Fig. 3). Figure 2. Bacteria inside the stratum corneum (TEM, ×,25,000) Figure 3. Hairy surface from the causative agent (TEM, ×,106,000) Crateriform pits ( Fig. 4) and small incipient lesions ( Fig. 5) were easily identified on the plantar surface by SEM. On examination of the floor of these lesions, tunnel openings were found ( Fig. 6) in which bacteria could be observed. With higher magnification, the transversal septation, seen by TEM, was also shown with SEM ( Fig. 7). The normal appearing plantar skin was also examined, showing incipient bacterial colonies with tunnels without keratin loss ( Fig. 8). Figure 4. Pitted keratolysis with two incipient lesions on the right side (SEM, ×,77.5) Figure 5. Higher magnification of the incipient lesion from the right upper corner of Fig. 4 (SEM, ×,310) Figure 6. Tunnel openings in the floor of the pits (SEM, ×,15,500) Figure 7. Details of the bacteria; note the transversal septation (SEM, ×,31,000) Figure 8. The causative agent in tunnels in normal appearing skin (SEM, ×,4650) [source]

Circumscribed palmar hypokeratosis: clinical evolution and ultrastructural study after prolonged treatment with topical calcipotriol

JOURNAL OF THE EUROPEAN ACADEMY OF DERMATOLOGY & VENEREOLOGY, Issue 4 2005
F Urbina
Abstract Circumscribed palmar hypokeratosis is a recently described condition that consists of a solitary area of depressed skin affecting the palm (or sole). Its histopathological features include a thinned horny layer, a slightly diminished granular cell layer, and intraepidermal vacuolated cells. Prolonged treatment with topical calcipotriol resulted in complete recovery of the affected zone in the case reported here. A second biopsy of the lesion taken at around the fourth year of therapy showed a normalization of the granular layer, a reduction in the intraepidermal vacuolated cells, and a somewhat thicker horny layer. An ultrastructural study carried out at the same time showed a reduction in keratin bundles and keratohyalin granules, and an increase in lipid droplets up to the horny layer. These findings and the therapeutic response to topical calcipotriol support the concept that circumscribed palmar hypokeratosis is a focalized abnormal keratinization defect morphologically expressed at the granular and horny layers. [source]

Formation of a protection film on the human skin by microparticles

LASER PHYSICS LETTERS, Issue 9 2008
J. Lademann
Abstract Laser scanning microscopy and tape stripping, in combination with optical methods, were used to analyze the distribution and penetration of a barrier cream into the horny layer (stratum corneum) of the human skin under in vivo conditions. The barrier cream contained microparticles of 10 , 100 , m loaded with antioxidant substances. The cream was designed for protection of the skin surface against the destructive action of free radicals, produced by systemically applied chemotherapeutic agents reaching the skin surface via the sweat. Both methods were able to demonstrate that the barrier cream was distributed homogeneously on the skin surface forming a protection film. A penetration into deeper parts of the stratum corneum (SC) was not observed. (© 2008 by Astro Ltd., Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA) [source]

Circumscribed palmar hypokeratosis: clinical evolution and ultrastructural study after prolonged treatment with topical calcipotriol

Ultraviolet B induces hyperproliferation and modification of epidermal differentiation in normal human skin grafted on to nude mice

BRITISH JOURNAL OF DERMATOLOGY, Issue 4 2004
S. Del Bino
Summary Background For ethical and technical reasons, the in vivo biological effects of ultraviolet (UV) radiation on skin are difficult to study in human volunteers. The use of human skin grafted on to nude mice may circumvent this difficulty. Objectives To investigate the effects of a single moderate UVB exposure on human skin grafted on to nude mice. Methods Modifications of epidermal differentiation markers and patterns of keratin expression were assessed from 24 h to 14 days after a physiological UVB irradiation characterized by the induction of sunburn cells. Results During the first 48 h postexposure, involucrin, loricrin, transglutaminase type I, filaggrin and keratin K2e expression were altered together with the formation of abnormal horny layers. Constitutive keratin K14 was increased while keratin K10 expression was delayed. Newly synthesized keratins K6, K16, K17 and K19 were induced in parallel with an increase in the epidermal proliferation rate. A progressive normalization of both keratinocyte proliferation and differentiation took place during the following days, reaching completion within 2 weeks. Conclusions Exposure of human skin to a UVB dose corresponding to a mild sunburn reaction induces epidermal hyperproliferation and alterations of several constitutive differentiation markers, as well as a drastic modification in the pattern of epidermal keratins. Although these modifications were shown to be progressively reversed in a single exposure model, the data also suggest that subsequent UV exposures occurring during the recovery period may lead to potentially deleterious long-term consequences, such as photoageing and photocarcinogenesis. Grafted human skin appeared to be an attractive and promising model for investigating the biological consequences of UVB radiation in vivo. [source]