sodium-dodecyl-sulfate and Hyperplasia

We are investigating decellularized vein allograft as a scaffold to engineer a non-synthetic, small-diameter vascular graft. This study examines the in vivo behavior of this scaffolding after implantation into the arterial circulation.. Canine animals underwent bilateral carotid interposition grafting using jugular vein implanted as either: 1) fresh autograft, 2) fresh allograft, or 3) decellularized allograft. Decellularization was achieved using sodium dodecyl sulfate. Grafts were examined with duplex ultrasound biweekly to determine luminal diameter, thrombosis, stenosis, or anastomotic breakdown. After perfusion fixation at 2 or 8 weeks, grafts underwent histological, morphometric, and immunohistochemical examination.. All animals survived without neurological or hemorrhagic complication. No deterioration of graft integrity (rupture, aneurysm) was observed in any group. Luminal narrowing was observed in both allograft groups, but secondary to different pathology. Fresh allografts had significant mononuclear cell infiltrate, intimal hyperplasia, and intramural hemorrhage consistent with rejection. Conversely, decellularized allografts had minimal evidence of rejection but instead had a compact fibrin layer formed along their lumen. This fibrin layer was absent in the peri-anastomotic regions where endothelium had migrated from the native artery. By 8 weeks, decellularized grafts had repopulated with cells staining positive for smooth muscle alpha-actin.. After 8 weeks of arterial flow, decellularized vein allograft exhibits satisfactory strength, reduced antigenicity compared to fresh allograft, and supports cellular repopulation. These characteristics make it satisfactory for further tissue engineering; combined with luminal vascular cell seeding, it may prove useful as a small-diameter arterial bypass graft.

Topics: Animals; Biomechanical Phenomena; Carotid Arteries; Dogs; Endothelium, Vascular; Female; Graft Rejection; Hyperplasia; Immunohistochemistry; Jugular Veins; Sodium Dodecyl Sulfate; Tissue Engineering; Transplantation, Homologous; Tunica Intima; Ultrasonography; Veins

Although ultraviolet B (UVB) irradiation perturbs the skin barrier, little is known about the mechanism(s) with respect to the metabolism of ceramide (Cer). We examined changes in intercellular lipids in murine stratum corneum following UVB irradiation. A single UVB (75 mJ per cm(2)) irradiation caused a significant increase in transepidermal water loss, which plateaued at day 4. In parallel, covalently bound Cer was significantly decreased with the greatest decrease at days 3-4. In contrast, the levels of other free, non-bound lipids (including Cer or acylceramides) were significantly increased for Cer, or remained unchanged at day 4 compared with non-irradiated controls. RT-PCR analysis demonstrated a significant decrease in mRNA encoding transglutaminase-1 (TGase1). The peak occurred 2-4 d after a single UVB irradiation, a time when covalently bound Cer was significantly downregulated in concert with the disruption of the skin barrier. Furthermore, UVB-induced epidermal hyperplasia occurred to the greatest extent between 2 and 4 d following UVB irradiation. These results suggest that decreases in covalently bound Cer in the stratum corneum are mediated via the downregulation of TGase-1 as well as by the rapid induction of epidermal hyperplasia, which is attributable to the perturbation of the skin barrier induced by UVB irradiation.

Topics: Animals; Biological Transport; Ceramides; Epidermis; Female; Gene Expression Regulation, Enzymologic; Hyperplasia; Male; Mice; Mice, Hairless; Mice, Inbred BALB C; Physical Stimulation; RNA, Messenger; Sodium Dodecyl Sulfate; Sphingolipids; Surface-Active Agents; Transglutaminases; Ultraviolet Rays

Previous studies have suggested that susceptibility of skin to external agents increases in the dry winter season.. To test the hypothesis that environmental humidity affects skin sensitivity to irritants.. The epidermal hyperplasia induced by sodium dodecyl sulphate (SDS) under various humidity conditions was evaluated on the skin of hairless mice.. Mice kept under low humidity for 2 days showed more obvious epidermal proliferation 24 h after topical application of SDS than those kept under high or normal humidity for 2 days. In contrast, mice kept under high humidity for 2 weeks showed more obvious epidermal proliferation 24 h after topical application of SDS than those kept under low or normal humidity. The transepidermal water loss was altered significantly in the animals kept under high humidity for 2 weeks, although it was not altered during the first 7 days under either low or high humidity.. These results suggest that environmental humidity influences the sensitivity of skin to topical application of SDS and that increased sensitivity is not always associated with alteration of the water impermeability of the stratum corneum.

Topics: Analysis of Variance; Animals; Epidermis; Humidity; Hyperplasia; Mice; Mice, Hairless; Sodium Dodecyl Sulfate; Surface-Active Agents; Water Loss, Insensible

The effect of sodium lauryl sulphate (SLS) on cytokeratin (CK) gene expression in hamster cheek pouch epithelium was studied with a hybridohistochemical technique. Using specific human anti-sense RNA probes, the plausible hamster mRNA counterparts for these human CK mRNAs were localized by detection of heterologous hybrids. In comparison with normal epithelium, the expression and distribution pattern of CK mRNAs in the hamster cheek pouch were obviously changed after application of SLS. There was a decreased expression of CK mRNAs in the hyperplastic basal layer, and increased expression in the hypertrophic granular layer. Strikingly, hybridization with the human CK 18 cRNA probe revealed an additionally expressed CK mRNA in the SLS-treated epithelium that was not found in the untreated epithelium. The present study indicates that cRNA probes for human CK mRNAs can be used successfully, not only to distinguish between different hamster CK mRNAs but also to investigate changes in CK gene expression upon the induction of non-neoplastic and neoplastic alterations in the hamster cheek pouch model. This may help elucidate the molecular changes involved in epithelial pathologies.

Topics: Animals; Cheek; Cricetinae; Detergents; Epithelium; Gene Expression Regulation; Gene Expression Regulation, Neoplastic; Histocytochemistry; Humans; Hybridomas; Hyperplasia; Hypertrophy; In Situ Hybridization; Keratins; Male; Mesocricetus; Mouth Mucosa; Mouth Neoplasms; RNA Probes; RNA, Antisense; RNA, Complementary; RNA, Messenger; Sodium Dodecyl Sulfate; Surface-Active Agents

Epidermal hyperplasia is the response of the epidermis to external harmful stimuli. The control and regulation of this hyperplasia is not completely understood. It has been proposed that changes in the cellular sodium/potassium ratio are of importance in the regulation of cell proliferation. To evaluate if such a change in the elemental content of epidermal cells can be one factor to consider at irritant contact dermatitis, we performed a quantitative assessment of sodium lauryl sulfate (SLS)-induced contact reactions in the guinea pig. SLS was applied 1, 2 or 3 times and biopsies were obtained at 24 and 84 h after the last application. It was found that repeated exposures to SLS induced a hyperplasia of epidermis at 24 h persisting at 84 h. At 24 h there were significant changes in the sodium and potassium content of the keratinocytes. At 84 h there was still an increased potassium level in the cells and the sodium/potassium ratio was significantly decreased in epidermis exposed three times to SLS. This implies that changes in cellular sodium/potassium ratios occur in epidermal hyperplasia following irritant stimuli.

Topics: Animals; Electron Probe Microanalysis; Elements; Epidermis; Female; Guinea Pigs; Hyperplasia; Potassium; Sodium; Sodium Dodecyl Sulfate

A mild irritant reaction was induced by application of sodium lauryl sulphate to the skin of guinea-pigs. The response was analysed at 24 and 48 h after application using light microscopy, transmission electron microscopy and energy dispersive X-ray microanalysis (EDX). It was found that the sodium lauryl sulphate induced a hyperplastic response in the epidermis with an increased number of keratinocytes. This response was associated with significantly increased levels of intracellular sodium and chloride. The elemental changes were most marked at 24 h, whereas the number of keratinocytes was highest at 48 h. The pattern of the elemental changes and the ultrastructural alterations are compatible with initial membrane damage followed by a transient increase in proliferative activity. The present results demonstrate that EDX is a useful tool for the analysis of functional alterations in epidermal keratinocytes under pathological conditions.

Topics: Animals; Chlorides; Electron Probe Microanalysis; Epidermis; Female; Guinea Pigs; Hyperplasia; Keratins; Microscopy, Electron; Sodium; Sodium Dodecyl Sulfate

The innervation of the skin of hairless mice has been studied following induction of epidermal hyperplasia by physical and chemical methods. Physical stimuli comprised ultraviolet irradiation, heat, wounding, and friction. Effective chemicals included benzene, carbon tetrachloride, chloroform, creosote, formaldehyde, hexadecane, hydrobromic acid, sodium lauryl sulfate, and turpentine. Epidermal hyperplasia, however produced, was associated with growth of sensory nerve fibers into the outer part of the epidermis. Following a single 10-min exposure to an ultraviolet sunalmp at 40 cm, the nerves extended into the epidermis within 24 hr and disappeared during the second week as the epidermis reverted to its normal thickness. Repeated irradiation (until tumors appeared) was accompanied by persistent hyperplasia and neural invasion. Of 32 papillomas examined, intraepithelial nerves were found in 28. The presence and location of nerves in the tumor epithelium were related to the incorporation of tactile hair disc epithelium. The hyperplastic regenerative epithelium at the margins of skin ulcers were also invaded by nerves which sometimes followed the migrating epithelium across the ulcer floor. Since the regenerative epithelium was not directly treated, it was concluded that the proliferation of nervous tissue in response to skin injury was the result of the hyperplasia per se, regardless of the method used to produce it.

Topics: Acids; Alkanes; Animals; Benzene; Bromides; Carbon Tetrachloride; Chloroform; Creosote; Formaldehyde; Hot Temperature; Hyperplasia; Mice; Nerve Endings; Nerve Regeneration; Papilloma; Skin; Skin Diseases; Skin Neoplasms; Skin Ulcer; Sodium Dodecyl Sulfate; Turpentine; Ultraviolet Rays

Studies on how irritant materials might induce epidermal hyperplasia were initiated by investigating their influence on epidermal mitosis. 5% hydrochloric acid, neat dimethyl acetamide and 1% benzalkonium chloride had no effect. 5% benzalkonium chloride, however, produced a 10-fold increase in mitotic activity, while a dose response curve was seen with sodium lauryl sulphate (SLS) peaking at 1%. 1% SLS produced a remarkably uniform response for this type of assay and it is suggested that it might provide a useful model for situations of increased epidermal cell turnover such as psoriasis. It is also noted that there was apparently no direct relationship between gross inflammation and the mitotic response.

Topics: Acetamides; Adult; Allergens; Benzalkonium Compounds; Humans; Hydrochloric Acid; Hyperplasia; Irritants; Male; Mitosis; Patch Tests; Skin; Sodium Dodecyl Sulfate; Time Factors

Topics: Animals; Cell Differentiation; Cell Division; Epithelial Cells; Epithelium; Hyperplasia; Male; Metaplasia; Methylcholanthrene; Mice; Mice, Inbred Strains; Organ Culture Techniques; Prostate; Sodium Dodecyl Sulfate; Thymidine; Tritium; Vitamin A