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PubMed1996

Conductivities of pig dermis and subcutaneous fat measured with rectangular pulse electrical current.

We examined experimentally the relationship between perpendicular and tangential electrical conductivities, sigma, and peak current density J, in pig skin dermis and subcutaneous fat specimens by using a four-electrode measuring system with rectangular pulse electrical current (RPEC). We also investigated the relationship of the conductivity, sigma, vs. pulse rate, f. The rates were selected at 8, 32, 64, and 128 pulses per second (pps), and the pulse width was fixed at 140 microseconds. These values are often used in vivo to enhance cutaneous regeneration with RPEC stimulation. It was found that the conductivities may be approximated to be [equation: see text] for the skin dermis and [equation: see text] for the subcutaneous fat in the conditions of this experiment. These findings implies that the conductivities of pig skin dermis and subcutaneous fat are anisotropic, i.e., sigma x = sigma y not equal to sigma z. It was also found that the conductivities are independent of current density and pulse rate in the current range from 20 microA/cm2 to 120 mA/cm2.

Adipose Tissue↗
PubMed1992

Avian scale development. XVII: The epidermis of the scaleless (sc/sc) anterior metatarsal skin is determined, but the dermis lacks permissive cues for the patterned expression of the determined state.

Embryos homozygous for the gene scaleless (sc/sc) completely lack scutate scales and the beta strata which characterize terminal differentiation of the scale ridges located on the anterior metatarsal region of the foot. Although the sc/sc epidermis cannot undergo scale morphogenesis, it can respond to the inductive dermal ridges of normal scutate scales by generating beta strata. Recently, we discovered that the anterior metatarsal epidermis of normal embryos becomes committed to the formation of beta strata prior to morphogenesis of definitive scale ridges. Here, we examined the possibility that the sc/sc anterior metatarsal epidermis also becomes determined, i.e., committed to scutate scale-specific terminal differentiation. Experimental tissue recombinants were used to assess the ability of the sc/sc epidermis to generate beta strata. The results show that the germinative cells of the 15-day sc/sc epidermis are committed to generating beta strata, even though they have not undergone scutate scale morphogenesis. Thus, the mechanisms involved in establishing epidermal determination must differ form those regulating scale morphogenesis. In addition, we examined the formation of patterned, permissive cues in the anterior metatarsal and footpad dermises of sc/sc embryos. Analysis of recombinants showed that both the 15- and 20-day dermises from the sc/sc anterior metatarsal region fail to provide cues for beta stratum formation, when associated with the determined 15-day scutate scale epidermis. Likewise, the 15-day sc/sc footpad dermis cannot support beta stratum formation. However, 20-day sc/sc footpad dermis is able to support the generation of a few abnormally patterned beta strata, demonstrating that sc/sc dermis which has experienced even limited morphogenesis is able to provide permissive cues for the terminal differentiation of the scutate scale epidermis.

Animals↗
PubMed1995

Dermo-1: a novel twist-related bHLH protein expressed in the developing dermis.

Transcription factors belonging to the basic helix-loop-helix (bHLH) family have been shown to control differentiation of a variety of cell types. Tissue-specific bHLH proteins dimerize preferentially with ubiquitous bHLH proteins to form heterodimers that bind the E-box consensus sequence (CANNTG) in the control regions of target genes. Using the yeast two-hybrid system to screen for tissue-specific bHLH proteins, which dimerize with the ubiquitous bHLH protein E12, we cloned a novel bHLH protein, named Dermo-1. Within its bHLH region, Dermo-1 shares extensive homology with members of the twist family of bHLH proteins, which are expressed in embryonic mesoderm. During mouse embryogenesis, Dermo-1 showed an expression pattern similar to, but distinct from, that of mouse twist. Dermo-1 was expressed at a low level in the sclerotome and dermatome of the somites, and in the limb buds at Day 10.5 post coitum (p.c.), and accumulated predominantly in the dermatome, prevertebrae, and the derivatives of the branchial arches by Day 13.5 p.c. As differentiation of prechondrial cells proceeded, Dermo-1 expression became restricted to the perichondrium. Expression of Dermo-1 increased continuously in the dermis through Day 17.5 p.c. and was also detected in the dermis of neonates, but became downregulated in adult tissues. The Dermo-1 protein bound the E-box consensus sequence in the presence of E12, but transcriptional activity was not detectable. Instead, Dermo-1 repressed transcriptional activity of myogenic bHLH proteins. The expression pattern of Dermo-1 suggests that it functions as a regulator of gene expression in a subset of mesenchymal cell lineages including developing dermis.

Amino Acid Sequence↗
PubMed1983

Polyamine levels in normal human skin. A comparative study of pure epidermis, pure dermis, and suction blister fluid.

The polyamines putrescine, spermidine, and spermine were detected and measured in both free and total forms in man in pure epidermis, pure dermis, suction blister fluid, blood, and 24-h urines. The technique employed for polyamine measurement consisted in liquid chromatography by ion exchange using an automatic amino acid analyzer and a fluorescence detection system. Polyamine concentrations were found to vary significantly between the dermis and the epidermis, both quantitatively and qualitatively: spermidine and spermine levels were much higher in the epidermis than in the dermis, and putrescine&spermidine and spermidine/spermine ratios were much lower in the epidermis. These differences reflect the known differences in cellularity, proliferative activity, and differentiation between these two cutaneous regions. The high spermidine and spermine concentrations in the epidermis suggest that these substances play a special role in this tissue.

Adult↗
PubMed1982

A study of reactions to Corynebacterium parvum (C. parvum) in the brain and dermis of the rat.

A comparative analysis was made of the histological changes caused by Corynebacterium Parvum (C. parvum) infected into the brain and dermis of normal and C. parvum presensitized rats. Control rats were injected with saline. It was shown that for approximately 3 days after the intracerebral injection the brain reacted with a polymorphonuclear cell infiltration. This reaction was replaced in order by lymphocytes, macrophages, and finally by epithelioid cells progressing to granuloma. The histological changes were similar but more intense in the dermis than in the brain. Lymphocytes reached a peak by day 7, macrophages by day 3, and epithelioid cells by day 18. In comparison to the dermis, the cellular infiltration in the brain is more delayed, less intense and of longer duration. Intracerebral saline induced a moderate lymphocytic infiltrate, and in C. parvum presensitized rats a more intense macrophagic response. It is concluded that the brain of the rat, especially in presensitized animal, mounts an inflammatory response to C. parvum which is morphologically similar to that seen in the skin.

Animals↗
PubMedDate not supplied

Correction of bone deformity after resection of dermoid cyst using artificial dermis implantation.

We report cases of the dermoid cyst patients with a bone deformity that were treated with artificial dermis implantation. After resecting the tumor, three or five sheets of artificial dermis (Terudermis, Terumo Co. Ltd, Tokyo, Japan) are placed into the depressed site in order to create symmetrical surface with the contralateral side. Neither of the cases presented here showed allergic or infectious reaction during postoperative follow-up period. In both cases, the texture of the implanted region is almost the same as the contralateral side and is almost symmetrical. We believe that artificial dermis may be a useful implantation material to correct depressions in the patient with dermoid cysts.

Adolescent↗
PubMed1995

Lipoxygenase activity in rat dermis and epidermis: partial purification and characterization.

Lipoxygenase (LOX) activity in epidermis and dermis was distributed among microsomal and cytosolic fractions. The main products of polyunsaturated fatty acid metabolism were 12-hydroperoxy-cis-5,8,14, trans-10-eicosatetraenoic acid (12-HPETE), 15-hydroperoxy-cis-5,8,11, trans-13-eicosatetraenoic acid (15-HPETE) and 13-hydroxy-cis-9, trans-11-octadecadienoic acid (13-HOD). Enzyme activities were isolated from rat dermis and epidermis by ammonium sulphate precipitation, hydrophobic chromatography and gel filtration. In the dermis, activity was found at a molecular mass of 68 kDa, a pI of 4.6 and a Km of 50 microM. This activity was inhibited by known LOX inhibitors. The main reaction products indicated that this was 15-LOX. In the epidermis, activity was found in a fraction with a molecular mass of 68 kDa, a pI of 4.6 and a Km of 80 microM. Activity was inhibited by known LOX inhibitors whereas the reaction products indicated that this was 12-LOX. LOX activity in rat skin may involve one enzyme with dual regional specificities or may comprise two different enzymes.

Animals↗
PubMed1986

Cellular contribution from dermis and cartilage to the regenerating limb blastema in axolotls.

Using the triploid/diploid cell marker in the axolotl, Ambystoma mexicanum, we have analyzed the extent to which cells derived from the dermis and the skeleton contribute to the regenerating limb blastema. We found that dermal cells contribute 43% of the blastemal cell population whereas cells derived from skeletal tissue contribute only 2%. When compared to the availability of cells at the plane of amputation, dermal cells overcontribute by greater than twofold whereas skeletal cells undercontribute by several-fold. These data correlate with the effects that these two tissues have on the formation of the limb pattern during regeneration; dermis has a dramatic influence on pattern and skeletal tissue has virtually no effect. It is suggested that the fibroblasts present in the dermis and in other parts of the limb form virtually all of the mesodermal tissues in the regenerate with the exception of the muscle.

Ambystoma mexicanum↗
PubMed1993

The presence of myofibroblasts in the dermis of patients with Dupuytren's contracture. A possible source for recurrence.

Samples of skin and underlying cord obtained at dermofasciectomy for Dupuytren's contracture have been examined for the presence of smooth muscle alpha-actin (SM alpha-actin), a marker for myofibroblasts. 15 of the 20 samples stained positively for SM alpha-actin corresponding with areas of hypercellular Dupuytren's tissue. In 12 of these 15 samples SM alpha-actin-positive hypercellular Dupuytren's tissue extended into the dermis, in three cases reaching the epidermis. In eight samples, diffusely distributed cells positive for SM alpha-actin and resembling fibroblasts were seen in the dermis. These cells appeared to be separate from the Dupuytren's foci. The presence of hypercellular foci and isolated fibroblasts positive for SM alpha-actin within the dermis may explain the high recurrence rate of Dupuytren's disease after fasciectomy.

Actins↗
PubMed1986

Comparison of benzo[a]pyrene-DNA adduct levels in mouse and rat epidermis and dermis.

Male Swiss mice and Wistar rats were treated topically with 250 nmol/mouse and 750 nmol/rat of [3H]benzo[a]pyrene ([3H]BaP). The initial level of total BaP--DNA and the individual modified deoxyribonucleoside adducts were similar in the skin epidermis of the two species. The concentration of these adducts was approximately 3 times less in both mouse and rat dermis. The decreased amount of BaP bound to DNA of mouse dermis may be related to the resistance of this tissue to the carcinogenic action of BaP. The ability of both the mouse (susceptible) and rat (resistant) skin to form BaP-bound products similar in nature and ratio in the epidermal and dermal DNA, suggests that other mechanisms are involved in the difference in the biological response of epidermis versus dermis to the carcinogenic effect of BaP.

Animals↗
PubMed1988

7,12-Dimethylbenz[a]anthracene-DNA adducts in mouse skin, dermis and epidermis.

Female NIH Swiss mice were treated topically with either 0.01 or 0.1 mumol 7,12-[3H]dimethylbenz[a]anthracene and DNA was isolated either from the whole skin, the dermis or the epidermis. Levels of binding to DNA and levels of individual adducts formed were similar in all 3 tissue fractions for a given dose of carcinogen with levels for the epidermis being marginally greater than in the other fractions. In all tissue fractions, the syn dihydrodiol epoxide-deoxyribonucleoside adducts were responsible for a greater fraction of total binding at the higher, than at the lower, carcinogen dose. The mechanism of metabolic activation of 7,12-dimethylbenz[a]anthracene for DNA binding is, therefore, qualitatively the same in both the dermis and epidermis. Quantification of adducts suggests some subtle differences between the DMBA activating systems in dermis and epidermis.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1993

Studies of tissue cultured sliced dermis as a skin substitute.

A dermis slicer designed by the authors enabled us to prepare about 10 sheets of sliced dermal grafts (SDG), 300 micron(s) thick, from the dermis harvested from the back or buttocks of adult patients during operations. Such a sliced dermal sheet was stretched with one surface stuck on the base of a culture dish. It was then incubated in Dulbecco's essential medium for tissue culture, to which epidermal growth factor had been added. By the first week only its upper side was epithelialized from epithelial components in sliced dermis. The formation of basement membrane with anchoring fibrils was confirmed by electron microscopy. The appearance of type IV collagen and laminin was observed between epithelialized basal cells and the dermal layer. Thus, it is thought that the SDG is useful not only for immediate grafting, when epithelialization follows, but also as a substitute for free split thickness skin grafts following tissue culture.

Cells, Cultured↗
PubMed2006

The use of artificial dermis for reconstruction of full thickness scalp burn involving the calvaria.

The incidence of extensive full thickness scalp burn involving the calvaria is rare and can be very difficult to reconstruct, as the application of local or free tissue transfer is limited. Although wound closure can be achieved with bone debridement and immediate or delayed split-thickness autografting, the result may be problematic due to unstable skin graft surface. The use of artificial dermis that may provide stable thick coverage in the treatment scalp and skull burn has rarely been reported in literature. We encountered two patients who suffered from severe head burns involving the calvarium. Following debridement including the necrotic bone, the artificial dermis (Integra) was used for immediate wound coverage which was 15 cmx10 cm in one case and 5 cmx6 cm in another. Three weeks later, ultra-thin skin grafting was placed on the neodermis. Compared to split-thickness skin graft, this technique provides a thicker coverage for wound closure. Neither skin breakdown nor ulceration was noted in the 1-year follow-up. This paper reports the successful use of artificial dermis for reconstruction of severe scalp burn with calvarial bone involvement.

Adolescent↗
PubMed1978

Dermis-fat graft as a movable implant within the muscle cone.

A 31-year-old woman had an extruding ocular implant in her right orbit. After surgically removing the implant, we transferred an autogenous dermis-fat graft from the hip region to the freshly prepared socket. The graft was sutured to the conjunctiva, and a conformer was placed in the socket. Eight weeks postoperatively, the dermis-fat graft was covered with conjunctival epithelium and a prosthesis was fitted successfully. No evidence of infection has occurred. This technique of using composite dermis-fat grafts in enophthalmos avoids recurrent extrusions and corrects the cosmetic problems produced by migrating or extruding implants.

Adipose Tissue↗
PubMed1997

Growth inhibition of cultured fibroblasts by extracts from human dermis.

In incised wounds and deep partial thickness burns the resident fibroblasts in the dermis remain inactive. The fibroblasts responsible for repair at the dermal level come from the subdermal layer. The hypothesis is that the inactivity of the dermal fibroblasts is due to an inhibitory substance in the dermis. To test this hypothesis extracts were made of normal dermis and of mature scar tissue and these extracts were applied to fibroblasts growing in monolayer culture. Both extracts and cells were obtained from human tissue. It was shown that extracts, particularly the extract made with citric acid/citrate buffer, pH 3.5, caused inhibition of fibroblast growth. Present evidence suggests that the active principle may be a proteoglycan.

Cell Culture Techniques↗
PubMed1996

Long-term sun exposure alters the collagen of the papillary dermis. Comparison of sun-protected and photoaged skin by northern analysis, immunohistochemical staining, and confocal laser scanning microscopy.

BACKGROUND: Long-term solar irradiation produces both morphologic and functional changes in affected skin. Because collagen is the major structural component of skin, any alteration in its production or degradation could have profound effects on cutaneous functional integrity. OBJECTIVE: Our purpose was to investigate alterations in the production and morphology of collagen fibers brought about by long-term sun exposure. METHODS: We compared collagen and collagenase gene expression and collagen immunohistochemical staining and used confocal laser scanning microscopy for morphologic examination of dermal collagen fibers in photodamaged compared with sun-protected skin from the same persons. RESULTS: Despite a large increase in elastin messenger RNA in sun-damaged skin, collagen and collagenase gene expression remained essentially unchanged. However, striking alterations in the papillary dermis of photoaged skin were found, which revealed large, abnormally clumped elastic fibers and deformed collagen fibers of various diameters, replacing the normal architecture of the papillary dermis. CONCLUSION: Our data provide evidence for normal collagen gene expression in sun-damaged skin and suggest that degradation and remodeling of collagen take place in the papillary dermis accompanied by deposition of other matrix components, predominantly abnormal elastic fibers.

Blotting, Northern↗
PubMed1999

Collagen fibril aggregation-inhibitor from sea cucumber dermis.

Collagen fibrils from the dermis of the sea cucumber Cucumaria frondosa are aggregated in vitro by the dermal glycoprotein stiparin (Trotter et al., 1996). Under physiological ionic conditions stiparin appears to be both necessary and sufficient to cause fibrils to aggregate (Trotter et al., 1997). We report here the initial biochemical and biophysical characterization of a sulfated glycoprotein from C. frondosa dermis that binds stiparin and inhibits its fibril-aggregating activity. This inhibitory glycoprotein, which has been named 'stiparin-inhibitor,' has the highest negative charge density of all the macromolecules extracted from the dermis. SDS-PAGE reveals three approximately 31-kDa bands that stain with alcian blue but not with Coomassie blue. Analytical ultracentrifugation indicates a native molecular weight of 62 kDa. Transmission electron microscopy of rotary-shadowed molecules shows curved rods about 22 nm long. The glycoprotein does not bind collagen fibrils, but does bind stiparin with a 1:1 stoichiometry. The binding of stiparin-inhibitor to stiparin prevents the binding of stiparin to collagen fibrils. The carbohydrate moiety produced by papain-digestion of the glycoprotein retains all of its inhibitory activity. The carbohydrate moiety of the inhibitor is dominated by galactose and sulfate.

Amino Acids↗
PubMed2002

Validation of a microdialysis-gas chromatographic-mass spectrometric method to assess 8-methoxypsoralen in psoriatic patient dermis.

8-Methoxypsoralen (8-MOP) is currently used in PUVA therapy (psoralen+UVA) to treat dermatological diseases such as psoriasis, vitiligo and atopic dermatitis. The aim of this work was to validate a method for collecting 8-MOP from patient dermis by a non invasive technique, microdialysis, and then to assess this molecule by gas chromatography-mass spectrometry (GC-MS). 5-Methoxypsoralen (5-MOP) was used as an internal standard. The calibration curve demonstrated a linear relationship between the peak areas of 8-MOP and 5-MOP over a wide range of 8-MOP concentrations (0.9-100 ng/ml). Within- and between-run precisions were measured, using four different 8-MOP concentrations, which varied from 98.0 to 102.0% and from 98.5 to 101.8%, respectively. The limits of detection and quantification were 0.29 and 0.52 ng/ml, respectively. The method was validated and then applied to determine the pharmacokinetic of 8-MOP in ten psoriatic patient dermis, after oral intake of this drug. The results demonstrated that the association of microdialysis with the GC-MS method was an efficient procedure to collect and assess 8-MOP in human dermis, in vivo.

Adult↗