bluuebunny/crossref_metadata_2025 huggingface dataset:
Reconstruction of the Human Skin Equivalent in vitro: A New Tool for Skin Biology
Authors: Dubertret L.
Published: April 2009

By mixing normal human fibroblasts with collagen type I + III and taking advantage of the capacity of fibroblasts to contract collagen fibers, it is possible to reconstruct in vitro a simplified equivalent of the human dermis. This tridimensional culture system can be covered by keratinocytes making possible the study of dermoepidermal interactions. In this in vitro model, close to the in vivo situation, the skin cells interact with matrix molecules and are submitted to cell to cell communications. Under the influence of these interactions they differentiate. The predictivity of this tridimensional culture system for studying physiology, pathophysiology and pharmacology is discussed.
Effect of Ciclosporin A on Epidermal Keratinocytes in vitro: Lack of a Direct Effect on Calmodulin
Authors: Fairley Janet A. , Fung Peter D. , Ewing Nancy M.
Published: April 2009

Calmodulin, a major calcium-binding protein, is important in the regulation of cell proliferation. In human keratinocytes we found that culture confluence was accompanied by a decrease in calmodulin content. Ciclosporin A, 1–10 μg/ml, was found to inhibit the proliferation of the cells but did not affect their calmodulin content as measured by bioassay or radioimmunoassay.
Detection of DNA Adducts in Skin Biopsies of Coal Tar-Treated Psoriasis Patients: Immunofluorescence and 32P Postlabeling
Authors: Zhang Yu Jing , Li You , DeLeo Vincent A. , Santella Regina M.
Published: April 2009

A clinical therapy for psoriasis, a hyperproliferative disease of the skin, utilizes topical application of crude coal tar sometimes followed by UV irradiation (Goeckerman therapy). To investigate the formation of covalent DNA adducts resulting from this therapy, skin biopsies were obtained from treated patients and controls. Indirect immunofluorescence staining with antisera generated against benzo(a)pyrene diol epoxide-modified DNA was used to investigate cell-specific localization of adduct formation. Specific nuclear staining was detected in the epidermal cells of all biopsies from treated patients but not from control biopsies obtained from untreated individuals. 32P postlabeling of DNA isolated from the biopsies was used to determine the spectrum of hydrophobic adducts present. A pattern of multiple adducts was detected in the samples obtained from the treated patients but not from controls.
Importance of Blood Flow to the Local Distribution of Drugs after Percutaneous Absorption in the Bipediculated Dorsal Flap of the Hairless Rat
Authors: Auclair F. , Besnard M. , Dupont C. , Wepierre J.
Published: April 2009

In order to study the importance of cutaneous blood flow variations to percutaneous drug absorption and local distribution, a bipediculated dorsal flap was created in the hairless rat. This model allowed us to compare the percutaneous drug absorption on both sides of the flap, one with normal blood flow and the other with a reproducible blood flow decrease (60%) obtained by ligation of one pedicle. 14C-labelled compounds, progesterone (lipophilic), caffeine (amphiphilic) and urea (hydrophilic) were applied in ethanolic solution during 4 h on the two sides of the flap. When the cutaneous blood flow was lowered, the skin radioactivity increased greatly for caffeine (76% in superficial dermis, 67% in deep dermis), less for progesterone (37% in superficial dermis, 30% in deep dermis). For urea, no significant difference was observed between the two sides of the flap. Nevertheless, when the absorption of urea was promoted by application on stripped skin, radioactivity was greatly increased on the ligated side of the flap (240% in superficial dermis, 423% in deep dermis). Our results showed that a hydrophilic compound poorly absorbed (urea) was insensitive to cutaneous blood flow modifications whereas compounds readily absorbed (caffeine, amphiphilic; urea on stripped skin) or slightly absorbed (progesterone, lipophilic) exhibited local concentration phenomena in relation to cutaneous blood flow lowering.
Topical Application of Liposomally Entrapped Ciclosporin Evaluated by in vitro Diffusion Studies with Human Skin
Authors: Egbaria K. , Ramachandran C. , Weiner N.
Published: April 2009

The kinetics and extent of uptake of ciclosporin (CSA) in various strata of human cadaver skin upon topical application of several CSA formulations were determined by in vitro diffusion cell experiments. The CSA formulations tested included an oil-in-water emulsion and four liposomal systems. The accumulation of CSA in the stratum corneum at 24 h is in the order: ‘skin lipid’ multilamellar liposomes (MLV) > phospholipid MLV ≈ ‘skin lipid’ large unilamellar liposomes (LUV) > phospholipid LUV > > > emulsion. The total amount of drug in the deeper stratum corneum and deeper skin strata at 24 h is in the order: phospholipid MLV > ‘skin lipid’ MLV > phospholipid LUV > ‘skin lipid’ LUV > emulsion. Whereas ‘skin lipid’ liposomes were more effective than phospholipid-based liposomes in depositing drug in deeper skin strata for rodent species (mouse and guinea pig), the opposite effect was observed for human cadaver skin. More importantly, all the liposomal formulations tested were far more effective than the emulsion formulation in depositing CSA into the skin.
Transforming Growth Factor α: In vivo Release by Normal Human Skin following UV Irradiation and Abrasion
Authors: James Leslie C. , Moore Alison M. , Wheeler Larry A. , Murphy Gilliam M. , Dowd Pauline M. , Greaves Malcolm W.
Published: April 2009

Transforming growth factor Α (TGFΑ) is a keratinocyte-growth-stimulating factor which may have a role in epidermal hyperproliferation, psoriasis, and wound healing. Since increased epidermal proliferation occurs in response to UV radiation, we have measured the amount of TGFΑ in exudates from normal and UVB-irradiated human skin. Cutaneous exudates were obtained using the skin chamber abrasion technique from one side of the back of volunteers (n = 10) with normal skin (collected following skin contact times of 2 and 30 min). Exudates were similarly obtained from the contralateral side of the back at sites irradiated 2 h previously with 3 × the minimum erythemal dose UVB. Levels of TGFΑ were measured by radioimmunoassay. Normal human skin released TGFΑ immediately after abrasion: unirradiated, 63 ± 18 ng/ml; irradiated, 89 ± 15 ng/ml. Levels of TGFΑ increased within 30 min to 110 ± 14 ng/ml in unirradiated skin and to 190 ± 17 ng/ml in irradiated skin. Irradiated sites at 30-min time points were significantly higher (p < 0.05) than all other samples. The presence of releasable TGFΑ in normal skin suggests a role for TGFΑ in wound repair mechanisms.
Binding of Synthetic Analogues of Retinol and Retinoic Acid (CD-270 Derivatives) to Retinoid-Binding Proteins
Authors: Siegenthaler G. , Saurat J.H.
Published: April 2009

Cellular retinoid-binding proteins play an important physiological role in the mode of action of retinoids upstream from the nuclear receptors. Tritiated analogues of retinol (ROL) and retinoic acid corresponding to substituted benzo[b]thiophene (CD-270) alcohol and carboxylic acid, respectively, were used for the binding studies of the cellular retinoic acid-(CRABP-) and retinol-(CRBP-) binding proteins in human epidermal cells and serum retinol-binding protein (RBP). We show that [3H]CD-270 carboxylic acid binds specifically to CRABP, whereas the alcohol derivative binds strongly to CRBP. However, the low amount of CRABP present concomitantly with CRBP suggests that [3H]CD-270 alcohol might be oxidized into minute amounts of the corresponding carboxylic acid derivative. The acidic character of the alcohol goup due to the aromatic ring of CD-270 might also support a possible binding to CRABP. In contrast, both derivatives show no affinity to RBP. These results suggest that the binding site of RBP is more restrictive to the retinoyl moiety than the binding site of cellular retinoid-binding proteins and therefore tolerates less chemical modification on the hydrophobic part of the ROL molecule. Moreover, when using these derivatives as ligands 2.4 times more CRABP and 3.9 times more CRBP could be measured with the PAGE technique as compared when using the natural [3H]ligands. The CD-270 derivatives might therefore be used as stable ligands for the study of both CRBP and CRABP. Since CD-270(OH) binds to the CRBP this may lead to the development of new synthetic analogues of ROL which could be used as tools for the study of the role of CRBP in the transport and metabolism of ROL.
The Role of Growth Factors in Wound Healing
Authors: Blitstein-Willinger Eveline
Published: April 2009

Numerous growth factors are involved in the regulation of tissue repair and remodelling processes. The repair process is initiated by inflammation, a phenomenon that is regulated by components of the immune response such as cytokines, matrix elements and growth factors. These locally released growth factors or cytokines induce the recruitment, activation, mitogenesis and differentiation of various other cell types. It is improbable that all of them play a key role in the tissue repair process. Obviously, each of these factors may also influence normal tissue homeostasis. Therefore, the possible use of these factors for therapeutic intervention has to be considered carefully. Some of the important aspects of growth factors with regard to this topic will be discussed.
Potency Assessment of Topical Corticoids in the Vasoconstrictor Assay and on Tuberculin-Induced Inflammation
Authors: Schalla W. , Schorning S.
Published: April 2009

The topical anti-inflammatory activity of potent and very potent corticoids was studied in normal and inflamed skin using the vasoconstriction assay and tuberculin-induced inflammation in four double-blind intraindividual comparison trials. Instrumental techniques in addition to visual scores and several time points were applied to get better insight into the reliability of the models and the sensitivity of the different variables. Beta-methasone-17-valerate and two concentrations of prednicarbate were used as potent corticoids, clobetasol-17-propionate, betamethasone-17,21-dipropionate and different biopharmaceutical forms of desoximetasone (DOM) as very potent corticoids. Visual scores, the reactive skin hyperemia after arterial occlusion and skin colorimetry were used to quantify vasoconstriction; erythema scores, surface area of infiltration and changes in skin colorimetry, skin blood flow and skin temperature for the tuberculin reaction. The time courses of blanching (n = 20) and of the tuberculin reaction (n = 10) were described by orthogonal polynomials and the coefficients were statistically analyzed by nonparametric tests, the discriminative variables in tuberculin inflammation in addition by the parametric multiple analysis of variance. Important differences in the release rates of corticoids demand several assessment times and not just one as often used. The potency ranking may otherwise be misleading. In general, ointments released corticoids slowlier than the cream which in turn liberated slowlier than the gels. The DOM gel declined rapidly after an apparent peak at 5.5 h in terms of its blanching effect, but was nevertheless comparable after once-daily application to other very potent corticoids in its activity against delayed-type inflammation. Such differences may explain discrepancies found for some corticoid preparations between their
Mediator Secretion from Human Skin Mast Cells Provoked by Immunological and Non-Immunological Stimulation
Authors: Church Martin K. , Okayama Yoshimichi , El-Lati Suhad
Published: April 2009

Mast cells of the human skin not only release mediators following immunological activation, but may also be stimulated to release histamine by the neuropeptides substance P, vasoactive intestinal polypeptide and somatostatin or by other basic secretagogues such as morphine, poly-L-lysine and compound 48/80. Release of histamine under these conditions is rapid and accompanied by minimal generation of the eicosanoids, prostaglandin (PG)D2 and leukotriene (LT)C4. Transient elevations of intracellular calcium are associated with mediator secretion induced by both stimuli, that induced by anti-IgE being derived from extracellular sources through channels in the plasma membrane while that stimulated by neuropeptides is mobilized intracellularly. Similarly, elevations of intracellular cyclic adenosine monophosphate (AMP) induced by anti-IgE occur only in the presence of extracellular calcium whereas with substance P elevations are apparent even in the absence of extracellular calcium. With the latter stimulus, histamine release is complete before the peak cyclic AMP is achieved. Histamine release stimulated by both secretagogues is unaffected by sodium cromoglycate or nedocromil sodium but is reduced by both salbutamol and isobutylmethylxanthine. Despite these biochemical and temporal differences, degranulation induced by both secretagogues proceeds by compound exocytosis which is indistinguishable under the electron microscope.
Ultraviolet Radiation and the Development of Non-Melanoma and Melanoma Skin Cancer: Clinical and Experimental Evidence
Authors: Pathak Madhu A.
Published: April 2009

Clinical and experimental evidence explaining and supporting the role of UV radiation as a causal factor for the induction and promotion of nonmelanoma and malignant melanoma skin cancer are presented. While there is excellent animal experimental data and human epidemiologic evidence supporting the causal relationship of UVR (UVB, as well as UVA radiation) for basal and squamous cell carcinomas, the data establishing a direct causal relationship between melanoma and exposure to sunlight appear to be complex. They do, however, suggest a definite promotional role of sunlight in the causation of melanoma. Using a hairless pigmented mouse strain (Skh-hr2), experiments were initiated to examine the role of UVR in the induction of melanoma. A single application of DMBA as an initiator and subsequent thrice-weekly exposures to either UVB (290–320 nm) or UVA (320–400 nm) or the combined exposures of UVA and UVB resulted in the formation of blue nevus-like lesions. Repeated UVR exposures for over 30 weeks resulted in the development of melanoma (38 %), as well as lymphoma and squamous cell carcinoma only in those mice that were pretreated with DMBA and had developed nevi. Mice receiving UVB, UVA, or the combination treatments of UVB plus UVA without DMBA pretreatment developed papillomas and squamous cell carcinoma but no melanoma. These studies indicate that some initiation event is essential to transform melanocytes to blue nevus-like lesions before UVR (UVB + UVA) can act as a promoter and accelerate the development of malignant melanoma, as well as lymphoma.
H1 Antagonists in the Management of the Itch of Urticarias
Authors: Kobza Black Anne
Published: April 2009

This article reviews the effect of H1 antihistamines on the pruritus of urticaria, from articles in which their therapeutic effect on chronic idiopathic and physical urticaria is assessed. In limited studies available pruritus improved concomitantly with wealing by an average of two thirds, though the response in individual patients was variable. In some physical urticarias the pruritus and wealing showed disproportionate improvement compared to erythema. The minimally sedating H1 antihistamines were as effective or more effective than classical H1 antihistamines. The dose of antihistamines that totally abolished a histamine weal only partly reduced urticarial weals (therefore by inference also of the associated pruritus). Additional therapy aimed at pruritogenic mediators other than histamine would be expected to improve urticarial pruritus.
Assay of Erythromycin in Tape Strips of Human Stratum corneum and Some Preliminary Results in Man
Authors: van Hoogdalem Ewoud J.
Published: April 2009

The antibiotic erythromycin is used topically in the treatment of acne vulgaris. In order to evaluate the in vivo cutaneous absorption behavior of erythromycin in man, an analytical procedure for erythromycin in stratum corneum tape strips was developed. Erythromycin was extracted from tape strips using solid-phase extraction, followed by alkaline diethyl ether extraction. Reconstituted extracts were analyzed by RP-HPLC with electrochemical detection. This procedure proved to be adequate in a pilot experiment in man, topical erythromycin appearing to be distributed over the stratum corneum, its upper layers displaying an inward decreasing gradient.
In vivo Microdialysis Estimation of Histamine in Human Skin
Authors: Anderson Chris , Andersson Thomas , Andersson Rolf G.G.
Published: April 2009

Microdialysis, a new bioanalytical sampling technique, enables the measurement of substances in the extracellular space. This study investigates the use of the technique in the in vivo measurement of histamine levels in human skin. Microdialysis probes are equipped at the tip with a semipermeable polycarbonate membrane which permits the passive diffusion of substances. 16 probes were inserted, via a guide, into the skin of the ventral forearm of 8 patients or volunteers. The probe was perfused at a flow of 5 µ1/min, with samples being collected at intervals of 10 min and analysed by RIA technique. The mean histamine level in the first 10-min sample following probe insertion was 39.4 nM. The mean histamine value fell with successive 10-min samples (8.8, 4.6, 2.3 nM). An equilibration period of 40 min following probe insertion is suggested for histamine studies, where provocation of the skin is to be performed. Microdialysis appears to be a promising new tool for quantitative and chronological studies of cutaneous inflammatory mediators.
Transcutaneous CO2 and O2 Diffusion
Authors: Berardesca E. , Maibach H.
Published: April 2009

Transcutaneous gas measurements offer a useful tool for non-invasive monitoring of skin function, but are affected by several variables that restrict their use in clinical and investigative dermatology. Skin thickness, stratum corneum and barrier function damage, blood vessel reactivity, arterial-gas concentration, skin and environmental temperature are important factors influencing transcutaneous gas flux. Improvement of techniques and standardization of methods with guidelines for operators should improve this interesting research approach.
Effects of Retinoic Acid on lnterleukin-1α and -1β Expression by Normal Human Keratinocytes Cultured in Defined Medium
Authors: Gatto Hugues , Richard Marie-Hélène , Viac Jacqueline , Charveron Marie , Schmitt Daniel
Published: April 2009

In human epidermis, basal keratinocytes are the main source of interleukin-1 (IL-1), and IL-1α is the predominant form, whereas IL-1β appears to exist predominantly in cultured keratinocytes. We investigated the effects of retinoic acid (RA) treatments on IL-1α and -β protein and mRNA expression of normal human keratinocytes cultured in low-calcium defined medium with or without hydrocortisone. Radioimmunoassay showed that after stimulation by RA, the IL-1β intracellular level is predominantly increased, with no significant modification of IL-1α expression. The addition of hydrocortisone in the culture medium resulted in a decrease in RA-induced IL-1β overexpression, without notable modifications in untreated cultures. Release of both IL-1α and -β in culture super-natants was detectable only after RA treatment and in the absence of hydrocortisone. The overexpression of IL-1β in control and RA-treated cultures mainly concerned the 52- and 31- to 36-kD biologically inactive precursor forms. Northern blot using specific IL-1α and -β oligonucleotide probes showed that IL-1β mRNA predominate over IL-1α mRNA and reach a maximal level 6 h before the IL-1β protein peak. These findings indicate that in cultured keratinocytes intracellular IL-1β is preferentially increased by RA but in its immature forms. The significance of this overexpression remains to be elucidated.
Porphyrin Synthesis by Murine Epidermal Cells
Authors: He Dan , Karas Evan , Sassa Shigeru , Lim Henry W.
Published: April 2009

Incubation of murine epidermal cells with delta-aminolevulinic acid (ALA) resulted in a dose- and time-dependent accumulation of porphyrins, predominantly of protoporphyrin. Porphyrin accumulation decreased in the presence of iron, and the iron-mediated decrease was partially reversed by CaMg EDTA (1.25–10.0 mM), suggesting that there is functionally active ferrochelatase in these cells. This study suggests that these cells may be a useful model for the study of cutaneous porphyrin metabolism involving ferrochelatase activity.
Penetration of Sandimmune (Cyclosporin A) in Rat Skin in vitro
Authors: Schmook Fritz P. , Stütz Anton , Reinhardt Joerg
Published: April 2009

The effect of various fatty acids or alcohols on the penetration rates and skin concentrations of cyclosporin A (Sandimmune; CyA) was evaluated in an in vitro model using skin of hairless rats. The influence of chain length, number and position of double bonds and branching of the carbon chain of the enhancer were investigated. In addition the penetration dependency of CyA on the concentration of both enhancer and CyA was studied. CyA was quantitated by high-performance liquid chromatography. The penetration rates of CyA through rat skin decreased with increasing number of double bonds of the enhancer and decreasing CyA concentrations in the donor solution, and increased with increasing chain length of the enhancer. Enhancers increase penetration rates by a factor of up to 20–90 in alcoholic vs. maximally 5-fold in oily compositions. Enhancers increase skin concentrations of CyA by a factor of up to 10–25 in alcoholic and about 4–20 in oily compositions.
Glucocorticoid Effect on Hair Growth Initiation: A Reconsideration
Authors: Stenn K.S. , Paus R. , Dutton T. , Sarba B.
Published: April 2009

It has been demonstrated by various workers in the past that glucocorticosteroids block hair growth. Using the mouse model for studying hair growth induction we reexamined the effect of topically applied steroids on hair growth to establish at what stage the steroid block acts. In accord with studies by others, we found that these steroids block hair growth at the point of anagen initiation, but that once the steroid applications are stopped, hair growth starts. Since steroid withdrawal alone did not induce hair growth, it is clear that these steroids do not block, either spontaneous or manipulated, hair growth induction, but they do block, the apparent next step, i.e., hair formation. Moreover, since hair growth could be induced even while the animals were being treated with the steroid, the induction step appears independent of the steroid block-These studies and those of others lead us to conclude that these steroids block the expression of hair-forming genes, but do not interfere with the signal(s) that initiates those genes. This system appears to be ideal for identifying the signals (perhaps, genes) responsible for initiating hair growth.
Computerized Microassay of Keratinocyte Cell-Plastic Attachment and Proliferation for Assessing Net Stimulatory, Inhibitory and Toxic Effects of Compounds on Nonimmortalized Cell Lines
Authors: Grando Sergei A. , Cabrera Raul , Hostager Bruce S. , Bigliardi Paul L. , Blake John S. , Herron Michael J. , Dahl Mark V. , Nelson Robert D.
Published: April 2009

Testing of pharmacological agents that affect growth of epidermal keratinocytes (EK) requires a standardized assay. We have developed an assay measuring net effects of stimulatory (e.g. growth factors), inhibitory (e.g. methotrexate) or toxic (e.g. Triton X-100) compounds. The amount of crystal violet staining viable EK attached to the wells of standard 96-well microplates is measured in situ using an ELISA plate reader. Optical density readings are directly converted into cell counts by computer software. Counts obtained by this method strongly correlate with the results obtained using the [3H]thymidine uptake assay and direct cell counts. The assay standardizes measurements of nonimmortalized EK lines with different innate proliferative properties and allows accurate quantitation of EK numbers in the range of 2,500–500,000 EK/well.
Experimental Approaches for the Reconstitution of Hair in vitro
Authors: Arase Seiji , Shikiji Takanori , Uchida Naoyuki , Katoh Shouji , Fujie Takeshi , Urano Yoshio
Published: April 2009

When plucked follicles were cultured together with isolated dermal papillae in a collagen gel matrix, outer root sheath cells (ORSCs) grew more rapidly and actively than without the papillae. Cultured dermal papilla cells also activated the colony growth of ORSCs in vitro. These results may suggest the existence of some papilla-derived factor(s) activating the growth of ORSCs. In cultures of excised whole follicles whose dermal papilla had been removed, epithelial cells of bulb matrix origin grew out from the bulbous portion, and formed spikes. When a dermal papilla was implanted close to the follicle, the spikes elongated toward the papilla, and finally reached and surrounded it. This finding suggests that dermal papillae may produce some factor(s) attracting epithelial cells of hair bulb origin. In cultures of excised whole follicles, when the dermal papilla remained originally positioned in contact with the hair bulb matrix, the hair and follicle elongated for more than 1 week. But when the dermal papilla was detached from the bulb matrix, the matrix cells proliferated into the gel and formed a hair-follicle-like structure (folliculoid). In cultures of excised whole follicles whose papilla-matrix junction had been damaged by dispase, elongation of the hair and follicle was almost completely suppressed. Thus, the attachment of the dermal papilla to the bulb matrix appears to be necessary for normal hair and follicle growth.
Androgens Affect the Activity of Human Sebocytes in Culture in a Manner Dependent on the Localization of the Sebaceous Glands and Their Effect Is Antagonized by Spironolactone
Authors: Zouboulis Christos C. , Akamatsu Hirohiko , Stephanek Katja , Orfanos Constantin E.
Published: April 2009

To investigate the varying response of the pilosebaceous unit to androgens functional studies were performed on the effects of testosterone and 5α-dihydrotestosterone on cultured human sebocytes derived from different skin regions. In addition, the effect of spironolactone on the proliferation of androgen-stimulated human sebocytes derived from facial skin was evaluated. Testosterone (1O-11 to 10-5M), 5α-dihydrotestosterone (10-11 to 10-5M) and spironolactone (10-12 to 10-7M) were added for 10 days as single substances or in combinations to human sebocytes in secondary culture maintained in a serum-free medium. Cell proliferation was assessed using a fluorometric assay. Intracellular lipids were extracted from sebocytes treated with androgens (10-7M) for 10 days after con-fluency. Testosterone inhibited the proliferation of sebocytes derived from the legs with a 50%-inhibitory concentration at 10-5M and induced a 50% decrease of intracellular lipids. In contrast, 5 α-dihydro testosterone stimulated the activity of leg sebocytes with a 50% increase of proliferation at 10-5M, and a 175% increase of intracellular lipids. On the other hand, the proliferation of facial sebocytes was significantly stimulated by testosterone with a 50%-stimulatory concentration at 10-6 to 10-5Mand mostly by 5α-dihydrotestosterone with a 50% enhancement at 10-8 to 10-7M. Spironolactone inhibited the proliferation of facial sebocytes in a dose-dependent manner with a 25%-inhibitory concentration at 10-9M. Simultaneous treatment of facial sebocytes with spironolactone and testosterone or 5α-dihydrotestosterone resulted in decreased proliferation when compared to the growth obtained under androgens alone. Moreover, spironolactone at 10-7M neutralized the stimulatory activity of 5α-dihydrotestos-terone at all concentrations tested. In contrast to previous reports of no androgen effect on human dermal papilla cells in culture, our results show a specialized response of human sebocytes to androgens dependent on the localization of the sebaceous glands. The direct inhibition of sebocyte proliferation by spironolactone and its antagonistic activity to androgens at the cellular level are indicative of a receptor-monitored effect.
The Phototrichogram: Analysis of Some Technical Factors of Variation
Authors: van Neste Dominique J.J. , de Brouwer Bernadette , de Coster Walter
Published: April 2009

Photographic methods for hair evaluation are frequently proposed as an alternative to more invasive methods (trichogram or biopsy). The reliability in terms of quantitative follow-up of hair growth has not been evaluated properly. We report results of comparative studies of scalp hair evaluation with various photographic methods. Statistically significant findings were a better detection of scalp hairs using the original enlargement × 3 as compared to × 2 (212 vs. 167 hair follicles/cm2) and a more acceptable estimate of linear hair growth rate with ‘scalp immersion proxigraphy’ (SIP) (0.317 mm/day) as compared with classical phototrichogram pictures where this variable was underestimated by 30% on average (0.27 mm/day). SIP-generated linear hair growth rates were very close to the micrometric method (0.37 mm/day). Therefore SIP × 3 images appear preferable for hair growth monitoring during clinical trials.
Tumors of the Pilosebaceous Unit
Authors: Waibel Maja , Blume Ulrike , Anhuth Dieter , Almond-Roesler Brigitte , Orfanos Constantin E.
Published: April 2009

Appendage tumors of the pilosebaceous apparatus are relatively rare, and their clinical aspect is usually nonspecific. In most cases pilosebaceous tumors are benign; however, malignant neoplasias (e.g. trichilemmal carcinoma, malignant pilo-matricoma) have been described. In the present review we propose the classification of pilosebaceous tumors by degree and by direction of differentiation and by histological configuration. Three different histological patterns have to be distinguished: tumors with central dilated hair follicle, tumors consisting of epithelial islands and keratotic cysts in the corium and neoplasias with predominantly mesenchymal components surrounding epithelial formations. Careful histopatho-logical examination of pilar appendage tumors will help to classify the wide range of clinically and histologically different tumors and to establish the exact diagnosis.
Cancer Risk and Exposures to Carcinogens in Hairdressers
Authors: Skov Torsten , Lynge Elsebeth
Published: April 2009

A number of epidemiologic studies have focused on the risk of bladder and lung cancer in hairdressers and beauticians, and the risk of breast cancer, and bladder cancer associated with the private use of hair dyes has also been addressed. The most consistent, although by no means unequivocal, finding is the increased risk of bladder cancer in male hairdressers. The use of brilliantine containing p-dimethylaminoazobenzene could be suggested as a relevant exposure. We present recent incidence data on bladder cancer in Danish hairdressers showing relative risk (RR) = 2.05 (men) and RR = 1.75 (women) in 1970–1980 and RR = 1.17 (men) and RR = 0.88 (women) in 1981–1987. Furthermore, in female hairdressers, the risk of non-Hodgkin’s lymphoma was increased for the whole period of 1970–1987.
Effects of Cyclosporin A on Hair
Authors: Lutz G.
Published: April 2009

Cyclosporin A (CSA) is an immunosuppressive agent that has provided new approaches in transplantation medicine and in the treatment of autoimmune diseases. One of the most common dermatological side effects of oral CSA is dose-dependent hypertrichosis. This stimulating effect on hair growth encouraged a number of investigators to use CSA not only in the treatment of alopecia areata (AA), but also in male pattern alopecia (MPA). While oral application proved successful, the beneficial effect of topical application was very limited in both AA and MPA.
Echographic Evaluation with Image Analysis of Normal Skin: Variations according to Age and Sex
Authors: Seidenari S. , Pagnoni A. , di Nardo A.D. , Giannetti A.
Published: April 2009

In order to identify and characterize the sonographic variations between different age groups, 48 subjects, 24 aged 27–30, and 24 over 60, were studied with a 20-MHz B scanner on six skin sites. Images were evaluated by the instrument’s standard programme and by a new image analysis software package enabling the characterization of steady structures or transitory functional aspects of skin reactions, by highlighting areas in which the echo amplitudes are included within selected values, and by calculating their extension. Three bands were selected as intervals of interest, respectively, highlighting hyporeflecting parts of the dermis, tissue reflecting with intermediate amplitude values and hyperreflecting epidermis and dermis. This method was employed to assess skin thickness, demonstrating its decrease in elderly skin, to characterize and quantify the hypo-echogenic subepidermal band appearing in the elderly at volar and dorsal forearm skin, and to evaluate echogenicity of the upper and lower dermis. Our data show that there is a great regional variation in the behaviour of ultrasound reflection of elderly skin in respect to the skin of young subjects. However, a general trend can be identified, consisting in a shift from low-intensity ultrasound echoes, characteristic in the dermis of young subjects, to intermediate or high reflection amplitudes, which are more frequent in elderly skin. Thus, the echographic method provides two parameters for the evaluation of skin aging. Besides an accurate and early assessment of skin atrophy, it also enables an evaluation of physical properties of the skin, which do not influence the morphological aspect in microscopy, but induce variations of the acoustic behavior which are expressed by a modification ofthe reflectivity to ultrasound.
Comparison of the Effects of Calcipotriol, Prednicarbate and Clobetasol 17-Propionate on Normal Skin Assessed by Ultrasound Measurement of Skin Thickness
Authors: Lévy Jean , Gassmüller Johannes , Schröder Gertrud , Audring Heike , Sönnichsen Niels
Published: April 2009

In this study, we investigated the effect of calcipotriol, prednicarbate and clobetasol 17-propionate on skin thickness over a treatment period of 6 weeks. The study was conducted as a controlled, randomized, double-blind comparison. The influence of these drugs on normal skin under occlusive conditions was assessed visually and by measuring skin thickness using 20 MHz B mode ultrasound. Both topically applied glucocorticosteroids lead to a significant decrease in skin thickness. In contrast to the glucocorticosteroid-induced atrophy, calcipotriol application on normal skin leads to an increase in skin thickness in all volunteers. The effect remains constant for the duration of treatment. The cause of this increase seems to be an irritative reaction of the skin which was histologically investigated in one volunteer. The histological features of this reaction are characteristic for a subacute dermatitis. The implications of these findings for the therapeutic mechanism of calcipotriol are discussed.
Trichothiodystrophic Hair Reveals an Abnormal Pattern of Viscoelastic Parameters
Authors: Tsambaos D. , Nikiforidis G. , Balas C. , Marinoni S.
Published: April 2009

Separate analysis and quantitative determination of the viscous and elastic parameters of hair performed in 5 patients with trichothiodystrophy and in 20 sex- and age-matched control subjects revealed an abnormal pattern of the mechanical behavior of trichothiodystrophic hair. The change of the viscous parameter is probably associated with the profound alterations in the high-sulfur proteins of the interfilamentary matrix; the changes in the elastic parameters may be related to the reduced stability of the irregularly arranged microfibrils of trichothiodystrophic hair caused by the marked reduction of the disulfide cross-links.
Effect of Benzoyl Peroxide on Protein Kinase C in Cultured Human Epidermal Keratinocytes
Authors: Matsui Mary Steidl , Mintz Edward , DeLeo Vincent A.
Published: April 2009

Benzoyl peroxide (BzPO) has been the most widely used topical agent for acne since the 1960s. This is true despite numerous reports that BzPO can enhance the development of carcinomas from murine epidermal papillo-mas. Because activation of protein kinase C (PKC) is considered to mediate cellular responses to other epidermal tumor promotors, we wished to investigate the relationship between BzPO and PKC in cultured human epidermal keratinocytes (NHEK). We assayed (a) direct effects of BzPO on PKC activity in a cell-free system using semipurified human keratinocyte PKC, (b) BzPO effects on the subcellular distribution of PKC, and (c) BzPO modulation of NHEK proliferation and phorbol ester-induced differentiation. NHEK maintained in serum-free media (0.15 mMCa2+) were treated with concentrations of BzPO in acetone from 100 nM to 500 µM, with concentrations of acetone not exceeding 0.1%. No short-term translocation of PKC from cytosol to membrane was observed at any BzPO concentration. BzPO did not downregulate subcellular levels of PKC activity after 24 h of exposure. BzPO did not significantly antagonize phorbol ester-induced inhibition of proliferation or differentiation but did weakly antagonize Ca2+-induced differentiation. Consistent with a PKC-mediated mechanism for Ca2+-induced differentiation, BzPO inhibited both human and murine PKC in a cell-free system. These results suggest that BzPO does not promote malignant conversion through a PKC-dependent mechanism, and in fact, inhibits PKC activity in vitro.
The Penetration Enhancer SEPATM Augments Stimulation of Scalp Hair Growth by Topical Minoxidil in the Balding Stumptail Macaque
Authors: Diani Arthur R. , Skull Kathy L. , Zaya Matthew J. , Brunden Marshall N.
Published: April 2009

The purpose of this study was to determine if the penetration enhancer SEPATM (2-n-nonyl-1,3-dioxolane) would augment the scalp hair growth effects of topical minoxidil in the balding stumptail macaque. A 1-in2 area on the balding scalp of 40 adult female monkeys (four drug-treated and four vehicle-treated groups of 5 monkeys each) was topically treated 5 days/week, q.d. or b.i.d., with approximately 250 µl of minoxidil-SEPATM (2.5% minoxidil, weight/volume in 10% SEPATM, 25% propylene glycol and 65% isopropyl alcohol), Rogaine® topical solution (TS, 2% minoxidil, weight/volume in 20% propylene glycol, 60% ethanol and 20% water) or respective vehicles (without drug) for 16 weeks via paintbrush application. Scalp hair was collected by shaving and vacuuming the dosed area at baseline and at 4-week intervals. The shaved hair was filtered, weighed and recorded as the change from baseline. The q.d. and b.i.d. minoxidil-SEPATM groups displayed a significant increase in hair weight compared to their respective vehicles at week 4 whereas q.d. and b.i.d. Rogaine® TS groups were not active until week 8 and 12, respectively. Both minoxidil-SEPATM treatments produced significantly greater cumulative hair weight over the entire 16-week study compared to either of the Rogaine® TS treatments. Comparable increases in cumulative hair weight were evident between q.d. and b.i.d. minoxidil-SEPATM groups and between q.d. and b.i.d. Rogaine® TS groups. Twenty-four-hour urine samples were collected at steady state to assess urinary excretion of total minoxidil via high performance liquid chromatography analysis in each of the four drug-treated groups. Urinary levels of total minoxidil tended to be greater in minoxidil-SEPATM groups. However, due to high intragroup variation, only the b.i.d. minoxidil-SEPATM group showed a significant 2.8-fold elevation compared to the b.i.d. Rogaine® TS group. These data suggest that the penetration enhancer SEPATM influences the topical delivery of minoxidil resulting in earlier and greater stimulation of scalp hair growth in the balding stumptail macaque.
Acetaminophen-lnduced Toxicity to Human Epidermoid Cell Line A431 and Hepatoblastoma Cell Line Hep G2, in vitro. Is Diminished by Silymarin
Authors: Shear Neil H. , Malkiewicz Izabella M. , Klein Dwora , Koren Gideon , Randor Samuel , Neuman Manuela G.
Published: April 2009

The skin and liver may be targets for cytotoxicity induced by oxidative drug metabolites. We used human epidermoid A431 cells and human hepatoblastoma Hep G2 cells as the experimental model. The aim of the study was to investigate and evaluate the effect of silymarin on acetaminophen (APAP)-induced toxicity under controlled conditions. Silymarin is known to be a potent antioxidant that diminishes toxicity induced by a variety of other hepatotoxins (e.g. Amanita phaloides, algae’s toxins, carbon tetrachloride). Glutathione (GSH) depletion was enhanced by adding to the medium buthionine sulfoximine [L-buthionine- (SR)-sulfoximine, BSO]. Cells were incubated with high-concentration 5-20 mM APAP or Α-(minimum essential medium for 2-24 h to evaluate the drug’s ability to reduce cytoviability. Viability was then quantitated by metabolism of the tetrazolium dyes (MTT) and neutral red (NR). Cytoviability was 100% for controls. For Hep G2 treated for 24 h with 20 mM, APAP viability was 56.0% by MTT and 62.5% by NR. BSO-treated cells showed an enhanced cytotoxicity, determined by both assays. Administration of 0.5 mM silymarin reduced cytotoxicity significantly. In A431 cells, treatment with 20 mM APAP reduced viability by 57% (MTT) and 69% (NR) versus control (100%). BSO further decreased viability. Since incubation with silymarin showed significant protection against APAP toxicity, it can be considered a cytoprotective agent in this in vitro model of drug toxicity. GSH concentrations in both cell lines decrease significantly after exposure to 20 mM APAP, or 0.5 mM versus control (p < 0.05), and increased (p < 0.001) if incubated with APAP and silymarin. The protective effect could be through mitochondrial membrane stabilization and/or an increase in available GSH.
Synthetic Wound Dressings – Evaluation of Interactions with Epithelial and Dermal Cells in vitro
Authors: Wollina U. , Knöll B. , Prüfer K. , Barth A. , Müller D. , Huschenbeck J.
Published: April 2009

Comparative testing of seven wound dressings (WD) has been performed with human HaCaT keratinocyte and mouse 3T3 fibroblast cultures. To assess biocompatibility, morphologic examinations were combined with cell counting. Supernatants were subjected to measurements of tissue peptide antigen (TPS), soluble intercellular adhesion molecule 1 (ICAM-1), and interleukins (IL-1Α, -1Β, -6). Furthermore, monoxygenation, the reduced glutathione/oxidized gluthathione (GSH/ GSSG) ratio and lipid peroxides were determined. Initial morphologic events were noted within the first day of exposure to WD. After 72 h, inhibition of cell growth was observed in the presence of hydrocolloids and hydrogels. The cytochrome-P-450-dependent ethoxyresorufin 0-deethylation rate and the GSH/GSSG ratio were not altered by WD in HaCaT cells. Lipid peroxide generation, IL-1 and ICAM-1 were scarcely detectable. TPS and IL-6 release indicate the presence of an ‘activated stage’ of keratinocytes and fibroblasts exposed to WD. Peptide release in vivo may contribute to the beneficial effects of modern dressings in the treatment of superficial cutaneous wounds.
Cutaneous Permeability Barrier Repair following Various Types of Insults: Kinetics and Effects of Occlusion
Authors: Taljebini Mohamed , Warren Raphael , Mao-Qiang Man , Lane Elizabeth , Elias Peter M. , Feingold Kenneth R.
Published: April 2009

Previous studies have shown that acute disruption of the cutaneous permeability barrier by acetone results in an initial rapid phase of repair followed by a later, slower phase. In the present study, we demonstrate that manipulations which disrupt the barrier by other mechanisms, such as tape stripping or detergent treatment, have a similar pattern of barrier repair. In all three models, the return of lipid to the stratum corneum parallels the normalization of barrier function, and occlusion immediately after disrupting the barrier blocks both the return of lipid and the normalization of function. Moreover, occlusion beginning 6-8 h following barrier disruption blocks the late, slower phase of repair, indicating that the late phase can be inhibited independently of the initial phase. Lastly, both severe and relatively minor perturbations of the barrier elicit a repair response with a similar kinetic pattern. In summary, the present study demonstrates that barrier repair responses are similar regardless of the etiology or extent of barrier disruption.
Plasma Retinoids after Topical Use of Retinaldehyde on Human Skin
Authors: Sass J.O. , Masgrau E. , Piletta P.A. , Nau H. , Saurat J.-H.
Published: April 2009

Background: Retinaldehyde (RAL), a natural metabolite of β-carotene and retinol (ROL), is tolerated by human skin after topical application. Purpose: To see if topical application of a large quantity of RAL on human skin is associated with a detectable alteration of constitutive levels of plasma retinoids resulting from metabolism of RAL in the skin. Methods: Plasma retinoids [ROL, all-trans-retinoic acid (all-trans-RA), RAL, retinyl palmitate/oleate, 13-cis-RA and 4-oxo-13-cis-RA] were analyzed by high-pressure liquid chromatography. Determinations were done in 10 healthy male volunteers kept on a vitam-A-poor diet before, during and after daily topical application of 7 mg of RAL to 40% of the body surface for 14 days. Results: The introduction of a restricted vitamin A diet before RAL application resulted in a decrease in the plasma levels of ROL, all-trans-RA and retinyl palmitate/oleate. Topical application of RAL did not induce an alteration of the plasma levels of retinoid metabolites. No RAL was detectable in any of the plasma samples. Conclusion: The skin metabolism of topically applied RAL does not result in detectable alterations of constitutive levels of plasma retinoids in humans.
Influence of Pertussis Vaccine and Bacterial Endotoxin on Blood Leukocyte Counts and Numbers of Pre-Existing Antibody-Forming Cells in Aged Mice
Authors: Finger H. , Hof H.
Published: April 2009

The present studies were carried out in order to explore, whether or not senile mice react in the same manner to a single injection of either 50 μg Serratia marcescens endotoxin (ET) or 3 × 109 killed Bordetella pertussis organisms (PO) as young adult mice. This was not the case. The following essential differences were observed. (1) Aged mice produce PO-mediated blood leukocytosis to a distinctly reduced extent, as compared to young adult mice. (2) The injection of either ET or PO into adult mice led to a short-lived, but significant increase in the numbers of cells producing 19S hemolysins to sheep erythrocytes, whilst the response regarding those cells synthesizing 19S antibodies to rabbit erythrocytes was very poor. Thereby, the reactivity of young adult mice was found to be very homogenous. In contrast to untreated young adult mice, the spleens of untreated senile animals contained on the average larger numbers of plaque-forming cells, the values differing strongly from spleen to spleen. Following treatment with either ET or PO the senile mice showed extreme differences regarding their capacity to react with an increase in hemolysin-forming spleen cells, thereby, reaching the maximum response in each case later than young adult mice. (3) There was no close positive relationship between the existence of cells producing 19S hemolysins to sheep erythrocytes and the occurrence of those synthesizing corresponding antibodies to rabbit erythrocytes. (4) Aged mice showed about a 10-fold increase to the lethal action of ET, as compared to young adult mice.
Zytophotometrische Untersuchungen über altersabhängige Strukturveränderungen am Nucleoproteinkomplex von Leberzellkernen
Authors: Löhr J. , Heimer D.
Published: April 2009

Age-dependent changes of the DNA-nucleoprotein complex in hepatic cells of guinea pigs are analysed by a modified Sakaguchi reaction. There is a statistically significant difference of the capacity of stain affinity between cells of young and old subjects.