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PubMed1994

Effect of age on antioxidants and molecular markers of oxidative damage in murine epidermis and dermis.

This is the first study of antioxidants and oxidative-damage-related parameters in epidermis and dermis of the skin as a function of age. The four major antioxidant enzymes (catalase, superoxide dismutase, glutathione reductase, and glutathione peroxidase), hydrophilic and lipophilic antioxidants, and lipid hydroperoxides were assayed in both epidermis and dermis of young and old hairless mice. Catalase, superoxide dismutase, and glutathione reductase had similar activity levels in young and old animals. Only glutathione peroxidase from epidermis showed an activity decrease due to age. This decrease became apparent when enzyme activity was expressed per mg of total cellular protein. Hydrophilic and lipophilic antioxidants did not change as a function of age, nor did lipid hydroperoxide levels. Both the absolute level of oxidized glutathione and the ratio of oxidized to reduced glutathione were higher in dermis from old mice. These results suggest that skin aging is not accelerated in old age due to a general decrease in the antioxidant capacity of the tissue. The data are compatible, however, with the idea that continuous damage to skin tissue by free radicals occurs throughout an organism's lifetime because scavenging cannot be 100% efficient.

Aging↗
PubMed1988

Reconstitution of structure and cell function in human skin grafts derived from cryopreserved allogeneic dermis and autologous cultured keratinocytes.

Grafts of allogeneic dermis plus autologous epidermal cell cultures were used to replace extensively burned skin. Cryopreserved split-thickness cadaveric skin was grafted onto debrided burn wound, and autologous keratinocytes were cultured from uninjured donor sites. Several weeks later, allograft epidermis was abraded and replaced with the keratinocyte cultures. The final grafts were thus composites of autologous cultured epidermis and allogeneic dermis. In a case with 28 months follow-up, reconstitution of the dermal-epidermal (BMZ.1) and microvascular (BMZ.2) basement membrane zones was studied immunohistochemically and ultrastructurally. Immediately before grafting, thawed cryopreserved skin reacted with antibodies against laminin and type IV collagen in normal patterns. Twenty-nine days after grafting, BMZ.1 reacted weakly with both antibodies, and anticollagen type IV reactivity was absent from BMZ.2. Antilaminin reactivity of BMZ.2, however, was moderately intense, consistent with recent neovascularization. On day 29, the allograft epidermis was replaced with autologous keratinocyte cultures. Twenty-five days later (54 d after allografting), staining of both BMZs was intense with both antibodies. Ultrastructurally, at day 76 (47 d after culture placement) BMZ.1 revealed only small hemidesmosomes, few incipient anchoring fibrils, and a discontinuous lamina densa. BMZ.2, however, was fully reconstituted. By 124 d, both BMZs appeared normal. Observations in the dermis at 76 d included the presence of lymphocytes, organellar debris, and hyperactive collagen fibrillogenesis, all indicative of dermal remodelling. The microvasculature was well differentiated, but no elastic fibers or nerves were found. In the epidermis, melanocytes and evidence of melanosome transfer were seen at 5, 47, and 95 d after grafting of keratinocyte cultures. We conclude that the composite procedure reconstitutes skin with excellent textural and histologic qualities.

Basement Membrane↗
PubMed1989

Tissue amyloid P component in normal human dermis is non-covalently associated with elastic fiber microfibrils.

Tissue amyloid P component (TAP), a protein that crossreacts immunohistochemically with the normal plasma glycoprotein serum amyloid P component (SAP), is invariably associated with elastic fiber microfibrils in adult humans. We have investigated the nature of this association. Aliquots of minced, homogenized dermis, obtained following ethylenediamine tetraacetic acid (EDTA) separation of whole adult human skin, were extracted with different reagents, and the presence or absence of TAP in the pellet and in the supernatant following centrifugation was determined by SDS-PAGE and immunoblotting using anti-SAP antibodies. TAP was extractable from dermis using reagents which disrupt non-covalent bonds, including sodium dodecyl sulfate (SDS) and guanidine hydrochloride. TAP was not extracted by high molarity salt solutions, non-ionic detergents, or the reducing agents dithiothreitol and 2-mercaptoethanol. EDTA solution was similarly unsuccessful at eluting TAP from the dermal preparation, indicating that the association of TAP with elastic fiber microfibrils is not simply the result of Ca++-dependent binding. Collagenase solubilized some TAP, but this does not prove covalent linkage to elastic tissue of part of the TAP, because the apparent Mr of TAP extracted was identical to that of normal SAP subunits. We cannot completely exclude the possibility that a few subunits in each multimeric TAP molecule are covalently attached to the microfibrils. However, our findings that denaturing agents alone extracted most of the TAP from normal human dermis strongly suggest that the great majority of the dermal TAP is non-covalently bound to elastic fiber microfibrils. Thus TAP is not an integral constitutent of elastic fiber microfibrils.

Adult↗
PubMed1991

Penetration of lysophosphatidylcholine into the dermis.

The ability of Lysophosphatidylcholine (LPC) to penetrate into the dermis and its degradation were investigated in vivo using hairless rats. Phosphatidylcholine (PC) was used as a control. Radioactively labelled LPC and PC were applied on the surface of skin, and the radioactivities of the epidermis and dermis were measured at 8, 24, and 48 hours. The recoveries of radioactive materials of LPC and PC within the area of epidermis and dermis at 8 hours were 0.21% and 0.25%; at 24 hours, 0.68% and 0.31%; and at 48 hours, 0.42% and 0.92%. No radioactivity was detected in serum. The radioactive substances which had penetrated were identified as LPC, PC, diglycerides, and free fatty acids. It was also found that topical application of LPC did not change the structure of skin as seen by microscopical examination. These findings indicate that a small amount of LPC can penetrate without the damaging skin structure and is enzymatically degraded into several lipids. Since LPC has bactericidal and antiviral activity, this substance could be an useful agent for dermatological use.

Animals↗
PubMed1979

Distribution of mast cells in human dermis: development of a mapping technique.

A new method was developed to define the distribution of mast cells in normal human skin. The population density was determined in a number of zones of different depth in the dermis. Two regions of the same limb were studied systematically. Both were shown to have mast cell populations of similar size and distribution, with a maximum density immediately below the dermo-epidermal junction, gradually falling to a minimum density in the deeper layers of the dermis. Small secondary peaks were less clearly defined at the base of the dermis. These findings should provide baseline data for comparisons with mast cell population size and distribution in different areas of normal skin, or in similar areas in clinical disorders or experimental conditions.

Adult↗
PubMed1984

Cellular retinol- and retinoic acid-binding proteins in the epidermis and dermis of normal human skin.

The distribution of cellular retinol- and retinoic acid-binding proteins (CRBP and CRABP) in normal human epidermis and dermis was examined by gel filtration. We showed that CRBP is entirely bound to a lipid-protein aggregate and its free form is obtained through delipidation. The type of homogenization procedure appeared to be important for the recovery of CRBP in human skin. The level of CRABP was about 3.1 pmol/mg protein in the epidermis whereas it was only sporadically detectable in the dermis. In contrast, CRBP was found in both tissues at a concentration of about 1 pmol/mg protein. The difference in CRABP concentrations between epidermis and dermis might have biological and therapeutic implications. Dissociation constants (Kd) of CRABP and CRBP were respectively 2.2 X 10(-7) M and 2.51 X 10(-7) M. This method will facilitate the study of CRABP and CRBP in retinoid- responsive dermatoses and enable us to relate the therapeutic effects of retinoids to the levels of cellular retinoid-binding proteins in the skin.

Adult↗
PubMed1990

The ageing dermis: the main cause for the appearance of 'old' skin.

Ageing of the skin is associated with progressive atrophy of the dermis, as well as changes in the architectural organization, leading to folds and wrinkles. As the dermis comprises living tissue, dermal changes are not simply the sum of age-related changes occurring in the mesenchymal cells and the supporting macromolecular structures. Chronological ageing reduces the life of fibroblasts in vitro and, to some extent, in vivo; their potential for division being lower in the elderly. Fibroblasts replicate in vitro but only divide very slowly in vivo. Both endogenous factors, e.g. nutritional and endocrine status, and environmental factors, e.g. UV radiation, toxic compounds or free radicals, affect the functions of fibroblasts and the physical and chemical nature of the supporting macromolecules. Mechanical forces also play an important role in the architectural deterioration of the dermis. In vitro models have been developed using dermal cells and supporting tissue to investigate the factors involved in the ageing process.

Animals↗
PubMed1992

DERMIS: a computer system for assisting primary-care physicians with dermatological diagnosis.

DERMIS is a computerized skin disease diagnostic prompting system which has been derived from the prospective study of 5203 cases. It has been designed for use by non-dermatologists such as general practitioners. The program produces a list of reasonable diagnoses based on probabilities calculated using Bayes' theorem. Out of 221 precise diagnoses made by the dermatologist in the clinic, 42 groupings were created to encompass the most common or important diseases encountered in general practice. Four 'remainder' or 'send to specialist' groups were included for the 13% of uncommon conditions. The program, when tested by 'one out' analysis on the original cases, placed the correct diagnosis first on 76% of occasions, and within the first three on 95% of occasions. In 76 of 125 cases randomly selected from the data base, a request for diagnostic assistance had been made by the referring general practitioner. It has been estimated that in 54 of these 76 cases the DERMIS system could have provided differential advice with the correct diagnosis appearing at the top of the list. The system has been written in MUMPS and runs on an IBM-compatible desk-top computer. The software allows real time data entry. Arrangements are in hand for performing clinical trials of the system in general practice. If current performance is maintained, and the response to the system's output is favourable, then DERMIS might well enhance performance in medical decision making for the benefit of patients, medical services and budget holders.

Diagnosis, Computer-Assisted↗
PubMed1993

Levels of fluconazole in serum, stratum corneum, epidermis-dermis (without stratum corneum) and eccrine sweat.

The distribution in the skin of orally active antifungals and other drugs claimed to be active in the treatment of skin diseases is of major importance, but to date has been studied only rarely. In the present study the distribution of fluconazole in stratum corneum, epidermis-dermis (without stratum corneum), eccrine sweat and serum was studied in human male volunteers after dosages of 50 mg daily for 12 days and 150 mg once weekly for 2 weeks. In the present study high levels of fluconazole were found especially in the stratum corneum. At a dose of 50 mg once daily the concentration of fluconazole after 12 days was 73.0 micrograms/g and 7 days after cessation of treatment the concentration was still 5.8 micrograms/g. At the 150 mg once a week dose the concentration 7 days after the second dose was still 7.1 micrograms/g in stratum corneum indicating that medication once a week may be effective in the treatment of dermatomycoses. High concentrations, all above the serum concentrations, were also seen in sweat and epidermis/dermis. These results indicate that fluconazole is delivered to the stratum corneum, where it is accumulated, through sweat and by direct diffusion through the dermis-epidermis. These pharmacokinetic results indicate that the drug should be very effective in the treatment of dermatomycoses. An extremely high concentration of the drug in the stratum corneum combined with concentrations from 2.93 to 4.62 micrograms/g in the rest of the epidermis and dermis is important in the treatment of these diseases.

Adult↗
PubMed2005

Solvent-dehydrated cadaveric dermis: a new allograft for pubovaginal sling surgery.

AIM: The aim of this study was to evaluate the efficacy of solvent-dehydrated cadaveric dermis in pubovaginal sling surgery for the first time in the literature. METHODS: Twenty-five women with stress urinary incontinence underwent pubovaginal sling surgery using 2 x 12 cm allograft dermis. Preoperatively, all patients were evaluated by a detailed urogynecologic evaluation, voiding diary, pelvic examination and urodynamic investigation. Outcome was assessed by the Urogenital Distress Inventory short form and standardized follow-up questionnaires. RESULTS: Twenty (80%) patients were cured of stress incontinence symptoms. Seventeen wore no pad and three reported occasional stress urinary incontinence and used no or one pad at a mean follow up of 12 months. Five (20%) patients in our series experienced the same amount of leakage as before the surgery. Seventy-six percent of the patients indicated that urinary incontinence was no longer negatively affecting their daily life and were satisfied with the procedure. CONCLUSIONS: Questionnaire-based assessment of outcome suggests that solvent-dehydrated cadaveric dermis is effective in the treatment of stress urinary incontinence. However, larger and comparative prospective studies with long-term results and randomized comparison of tissue preparation techniques are warranted.

Adult↗
PubMed1986

Dermis-fat graft: evolution of a living prosthesis.

Over the past two years 15 dermis-fat grafts were performed. Ten were primary grafts, two were implanted because of migrated implants, two for extruding implants and one to correct deep superior sulcus recession. Our experience showed dermis-fat grafts to be an effective method of correcting orbital volume deficit, of maintaining satisfactory prosthetic motility and of preventing the development of conjunctival deficiency. In primary dermis-fat grafts fat atrophy was less than 10%, whilst in secondary implants fat atrophy was less than 30%. Complications were minimal in our small series.

Adipose Tissue↗
PubMed1995

Ultrastructural effects of topical tretinoin on dermo-epidermal junction and papillary dermis in photodamaged skin. A controlled study.

We examined the effects of daily topical application of 0.05% tretinoin cream on photodamaged Caucasian facial skin by electron microscopy. Specimens obtained pretreatment, after 6 and 12 months of tretinoin therapy (20 patients), and after 6 months of vehicle treatment (5 patients) were compared in a blinded fashion, with special attention to the dermoepidermal junction and papillary dermis. Baseline specimens disclosed various degrees of damage including reduplication of basal lamina, smudging and sparsity of collagen fibers, and nodular arrangement of degenerated microfibrils in the papillary dermis. No significant changes were observed at 6 months in the papillary dermis of either tretinoin-treated or vehicle-treated patients. After 12 months of tretinoin treatment, however, disorganized collagen fibers, which were conspicuous in 11 patients at baseline, were replaced by new well-organized collagen fibers in a wavy pattern in 6 patients. In addition, the amount of nodularly degenerated microfibrillar material decreased in 15 of 18 patients with this finding at baseline. In contrast, no significant change was noted in the number of anchoring fibrils per unit length of the lamina densa. These observations provide further evidence that topical treatment with 0.05% tretinoin produces papillary dermal reconstruction, for which more than 6 months of application were required.

Administration, Topical↗
PubMed1972

Inductive interactions between human dermis and chick chorionic epithelium.

In a study of specificity in mesenchymal-epithelial interactions, human embryonic dermis has been recombined with chick chorionic epithelium and cultured for 7 days on a host chick chorioallantoic membrane. Dermis from the sole of the foot or palm of the hand induces chick chorionic epithelium to form an epidermis that resembles chick rather than human epidermis. Chick epithelium, though it has the capacity to respond to a human dermal stimulus, is limited to forming chick-type tissue. The human dermis was modified in its turn by culture in combination with chick epithelium.

Animals↗
PubMed1993

Human and murine dermis contain dendritic cells. Isolation by means of a novel method and phenotypical and functional characterization.

Dendritic cells (DC) comprise a system of cells in lymphoid and nonlymphoid organs that are specialized to present antigens and to initiate primary T cell responses. The Langerhans cell of the epidermis is used as a prototype for studies of DC in the skin. We have characterized a population of DC in human dermis, one of the first examples of these cells in nonlymphoid organs other than epidermis. To identify their distinct functions and phenotype, we relied upon the preparation of enriched populations that emigrate from organ explants of dermis. The dermal cells have the following key features of mature DC: (a) sheet-like processes, or veils, that are constantly moving; (b) very high levels of surface MHC products; (c) absence of markers for macrophages, lymphocytes, and endothelium; (d) substantial expression of adhesion/costimulatory molecules such as CD11/CD18, CD54 (ICAM-1), B7/BB1, CD40; and (e) powerful stimulatory function for resting T cells. Dermal DC are fully comparable to epidermis-derived DC, except for the lack of Birbeck granules, lower levels of CD1a, and higher levels of CD36. DC were also detected in explants of mouse dermis. We conclude that cutaneous DC include both epidermal and dermal components, and suggest that other human nonlymphoid tissues may also serve as sources of typical immunostimulatory DC.

Animals↗
PubMed1984

Anchoring filaments of the amphibian epidermal-dermal junction traverse the basal lamina entirely from the plasma membrane of hemidesmosomes to the dermis.

An electron microscopical study of the epidermal-dermal junction in the axolotl and adult Rana pipiens has been carried out. This shows that filaments of about 12nm in diameter, known as anchoring filaments, pass from the hemidesmosomes at the base of the epidermal cells across the basal lamina to the dermis. There they may unite to form broader fibres, known as anchoring fibrils, or may simply form bundles. In the axolotl, particularly, the anchoring fibrils or bundles of anchoring filaments, enmesh with the collagen fibres of the dermis. Removal of epidermal cells with EDTA results in separation along a plane in the lamina rara of the basal lamina, i.e. between the plasma membrane of the cells and the lamina densa. The anchoring filaments remain inserted into the lamina densa. Hemidesmosomal plaques are no longer visible in regions of the plasma membrane that have been separated from the basal lamina by EDTA, and no evidence was found that plaques are engulfed by the cells. It is proposed that the hemidesmosome-anchoring filament system provides a structural link between the collagenous filament system of the dermis and the intracellular cytokeratin filament system of the epidermis, which, in turn, is linked between cells by desmosomes.

Ambystoma↗
PubMed1996

Morphology and biomechanics of the microfibrillar network of sea cucumber dermis

The principal component of the body wall of the sea cucumber Cucumaria frondosa is a dermis consisting of collagen fibrils, microfibrils, proteoglycans and other soluble and insoluble components. A major structural constituent of the dermis is a network of 10­14 nm diameter microfibrils, which surrounds and penetrates bundles of collagen fibrils. This network has been extracted and purified using guanidine and bacterial collagenase. Tensile testing of the microfibrillar network in artificial sea water demonstrates that it is reversibly extensible up to approximately 300 % of its initial length. It behaves like a viscoelastic solid, having a long-range elastic component as well as a time-dependent viscous component. Reduction and alkylation of the cysteine residues in the network do not change its breaking strain or strength, but greatly increase the compliance of the network until, near the breaking strain, the tensile resistance rapidly increases. These data suggest that the strength of the network is due to non-reducible crosslinks, while its elasticity is dependent upon disulfide bonds. In deionized water, the network becomes swollen and, although it remains elastic, is much more compliant than when tested in artificial sea water. Examination of whole tissues and purified networks with the electron microscope reveals structures similar to vertebrate fibrillin-containing microfibrils. Considering that the dermis of C. frondosa is a mechanically mutable tissue in which elongation is accompanied by the sliding of collagen fibrils past one another, the microfibrillar network may act to maintain the orientation of fibrillar components during movement and may also provide a long-range restoring force.

Journal Article↗
PubMed2003

Cellular response in the dermis of common wombats (Vombatus ursinus) infected with Sarcoptes scabiei var. wombati.

The cellular response in the dermis of common wombats (Vombatus ursinus) with sarcoptic mange exhibited some typical aspects of an immune response to Sarcoptes scabiei. There was an induction phase for wombats experimentally infected with S. scabiei represented by absence of a dermal inflammatory infiltrate for at least 12 days after infection. T lymphocytes, plasma cells, mast cells, and neutrophils then entered the dermis, consistent with a type IV (delayed) hypersensitivity response. In free-living wombats with severe parakeratotic sarcoptic mange eosinophils were also present in the dermis suggesting that a type I (immediate) hypersensitivity response may develop after a type IV hypersensitivity response. Absence of plasma cells and B lymphocytes in free-living wombats with severe parakeratotic sarcoptic mange compared with their presence in wombats experimentally infected with S. scabiei suggested that some immune tolerance may develop with severe infections. A large proportion of cells in the dermal response were not identified but were possibly cells of connective tissue. The thickness of the epidermis increased within 4 days in response to S. scabiei infection. Some antibodies raised against human leucocyte antigens CD3, CD5, HLA-DP, DQ, DR, and CD79b cross-reacted with leucocyte antigens of common wombats and were used to identify cell types in inflammatory infiltrates using immunohistochemistry.

Animals↗
PubMed1999

[Artificial dermis].

An artificial dermis, composed of an inner layer of collagen sponge and an outer silicone layer, was developed by modifying the material reported by Yannas et al. When the artificial dermis is placed on full 14-thickness skin defects, the pores of the inner collagen sponge are infiltrated by fibroblasts and capillaries. This cell-infiltrated membrane is gradually converted into a synthesized connective tissue matrix, similar to true dermis, as the original network of collagen sponge is biodegraded. The secondary skin graft takes easily and postoperative contraction is minimal even if a very thin split-thickness skin graft is used. The requirement for two-stage surgery and long hospitalization remain disadvantages of the material. Consequently, application of the material is limited to cases in which the advantages outweigh the disadvantages. Deep skin defects with partial exposure of bone or muscle appear to be the most suitable indications for the material. Shallow but very wide skin defects also seem to benefit from the application of the material.

Adult↗