bluuebunny/crossref_metadata_2025 huggingface dataset:
Development of an Intracutaneous Depot for Drugs
Authors: Ritschel W.A. , Panchagnula R. , Stemmer K. , Ashraf M.
Published: April 2009

In previous studies we reported that the permeation of dexamethasone and hydrocortisone across the skin was decreased and penetration into the skin was increased in the presence of Transcutol® (TC) when compared to water as a solvent. The objective of this investigation was to study the effect of TC on the binding of dexamethasone and hydrocortisone to the skin, and on the accumulation and retention in the skin. Adsorption and desorption studies were conducted for dexamethasone and hydrocortisone with full thickness skin (FTS), and epidermis.The amount of dexamethasone and hydrocortisone adsorbed and desorbed with FTS and epidermis was essentially the same. In the presence of TC the amount of dexamethasone and hydrocortisone adsorbed was increased by 100% with both FTS and epidermis, whereas there was no difference in the amount of dexamethasone and hydrocortisone desorbed. A topical delivery system was developed with and without TC and was evaluated in vivo using the rat as an animal model for hydrocortisone accumulation after multiple dosing. The systemic body burden was reduced by 70% and skin retention of hydrocortisone was incresed by 100% in all the layers of the skin. The detection of hydrocortisone accumulation and retention were studied by autoradiography and electron microscopy, and the results support the hydrocortisone depot in the skin due to TC.
A Direct Comparison of Pharmacologic Effects of Retinoids on Skin Cells in vitro and in vivo
Authors: Varani James , Gendimenico Gerard J. , Shah Biren , Gibbs Douglas , Capetola Robert J. , Mezick James A. , Voorhees John J.
Published: April 2009

The purpose of these studies was to directly compare the pharmacologic effects of retinoids on cutaneous cells in vitro and in vivo. Previously, it was demonstrated that all-trans-retinoic acid stimulates the proliferation of growth-arrested human keratinocytes and fíbroblasts in culture. In the present studies, all-trans-retinoic acid was compared to three other retinoids – 13-cis-retinoic acid, P-[(E)-2-(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-napthalenyl-l-propenyl] benzoic acid (TTNPB) and M-[(E)-2-(5,6,7,8-tetrahydro-5,5,8,8,-tetramethyl-2-napthalenyl-l-propenyl] benzoic acid (meta-carboxy-TTNPB] – for growth stimulation using a cultured human squamous epithelial cell line (UM-SCC-1) and human dermal fíbroblasts. These four retinoids were also evaluated for their effects on reduction of horn-filled utriculi when topically applied to the skin of rhino mice. All-trans-retinoic acid stimulated proliferation of both fíbroblasts and epithelial cells over concentrations ranging from 0.01 to 1.0 μg/ml. In fíbroblasts, 13-cis-retinoic acid was less potent than all-trans-retinoic acid, whereas, in epithelial cells these two retinoids were equipotent. In contrast, TTNPB was more potent than all-trans-retinoic acid at stimulating the growth of both fíbroblasts and epithelial cells. The analog, meta-carboxy-TTNPB was essentially inactive as a growth stimulator of both cell types. In the rhino mouse utriculus reduction model, the rank order of potency for the retinoids was the same as that for in vitro cell growth stimulation (TTNPB > all-trans-retinoic acid > 13-cis-retinoic acid). Meta-carboxy-TTNPB was inactive at reducing utriculi at a dose of 5,000 times the ED50 of TTNPB. In summary, the results of these studies show that the effects of retinoids on stimulating proliferation of fíbroblasts and epithelial cells correlate with their effects at reducing utriculi in the rhino mouse. Therefore, these in vitro models appear to have good relevance for studying the mechanisms of the pharmacologic effects of retinoids in vivo.
Interleukin-4 Production by FcεR+ Cells
Authors: Paul William E.
Published: April 2009

Among non-B, non-T cells in the spleen and among unfractionated bone marrow cells, there is a population of cells that are capable of producing IL-4 in response to cross-linkage of FcεRI or FcγRII. Their IL-4-producing capacity is strikingly enhanced by treatment of the cells or of the animals donating such cells with interleukin-3 (IL-3). FcεR+ cells constitute 1–2% of splenic non-B, non-T cells and of bone marrow cells from normal donors but they contain all the capacity to produce IL-4 in response to cross-linkage of FcεRI or FcγRII or to treatment with ionomycin. FcεR- cells fail to make such responses. Electron-microscopic analysis indicates that virtually all the granulated or vacuolated FcεR+ cells are of the basophil lineage. However, it has not yet been resolved whether these cells or immature mast cells, presumably in the FcεR+ granule/vacuole-negative cell population, are the principal producers of IL-4 in response to these stimuli.
Coculture of Neoplastic and Normal Keratinocytes as a Model to Study Tumor Promotion
Authors: Hennings Henry , Lowry David T. , Robinson Victor A.
Published: April 2009

In order to study skin tumor promotion, a cell culture model system analogous to initiated mouse epidermis was developed. Keratinocytes of the neoplastic cell line 308 display the initiated phenotype since papillomas are produced when the cells are grafted to the backs of athymic mice. Coculture of a small number of these initiated cells with confluent normal keratinocytes results in the suppression of growth of colonies of 308 cells. This inhibition, which is calcium dependent, epidermal cell specific, and requires cell contact, can be overcome by exposure to various tumor promoters. Promoters and antipromoters of diverse structure and mechanism of action are recognized in this keratinocyte coculture model.
Comparative Atrophogenicity Potential of Medium and Highly Potent Topical Glucocorticoids in Cream and Ointment according to Ultrasound Analysis
Authors: Kerscher M.J. , Korting H.C.
Published: April 2009

24 healthy volunteers with no history of skin disease were entered in a 6-week double-blind randomized study to compare the atrophogenicity potentials of both cream and ointment forms of triamcinolone acetonide and clobetasol propionate. The atrophogenicity potential of cream preparations turned out to be greater than that of ointment preparations containing identical amounts of the same glucocorticoid. This result proves both the reproducibility of the assay and the general character of the phenomenon in view of the limited previous evidence.
Effect of Substance P and Sar9Met(O2)11-Substance P on Cutaneous Capillary Permeability in Guinea Pig Skin
Authors: Doutremepuich J.D. , Barbier A. , Vilain P. , Lacheretz F.
Published: April 2009

The purpose of this study was to assess the effect of several drugs on the increase in cutaneous capillary permeability induced by intradermal injection of substance P (SP) and Sar9Met(O2)11-SP in guinea pig skin. On the one hand, the increase in cutaneous capillary permeability was partly reduced by spantide, promethazine, atropine or SR 40037, an inhibitor of the angiotensin-converting enzyme. On the other hand, norepinephrine and B3824, a B2-antagonist of bradykinin, showed an enhancing effect. Our results suggest that the effect of SP and Sar9Met(O2)11-SP in guinea pigs is partly mediated by histamine and acetylcholine, and that there is a relationship between tachykinins and bradykinin.
In vivo Evaluation of the Penetration of Topically Applied Drugs into Human Skin by Spectroscopic Methods
Authors: Sennhenn Bernd , Giese Karl , Plamann Karsten , Harendt Norbert , Kölmel Klaus
Published: April 2009

Spectroscopic techniques are reported on which allow to study in vivo the penetration behaviour of topically applied light-absorbing drugs into human skin. Remittance specroscopy, a purely optical method, provides a good tool in both, skin adaptation by use of a remote viewing head coupled to the spectrometer via optical fibres, and adequate sensitivity for the detection of small amounts of the applied drugs. The measuring depth in the skin is determined by the wavelength-dependent optical penetration depth, which itself depends on light absorption and light scattering. In the UV-spectral region the optical penetration depth is of the order of the thickness of the stratum corneum (UV-A) or of only a superficial part of it (UV-B, UV-C). Fluorescence spectroscopy, another optical method, offers two kinds of drug detection, a direct one in case of self-fluorescent drugs or an indirect one being based on the light absorption of the drug, which may give rise to a screening of the self-fluorescence of the skin itself or of an applied marker. The measuring depth is comparable to that achieved with remittance spectroscopy. A third method is photothermal spectroscopy which is determined by thermal properties of the skin in addition to optical properties. Photothermal spectroscopy is unique in that it allows depth profiles of drug concentration to be measured non-invasively, as the photothermal measuring depth can be changed by varying the modulation frequency of the intensity-modulated incident light. Results of measurements demonstrating the potentials of these spectroscopic methods are presented.
Evolution and Function of Innate Immune Receptors – Insights from Marine Invertebrates
Authors: Rosenstiel Philip , Philipp Eva E.R. , Schreiber Stefan , Bosch Thomas C.G.
Published: April 2009

Innate, nonadaptive immune receptors represent phylogenetically ancient first-line sensors of invariant non-self patterns and other cellular danger signals. From lower animal phyla to vertebrates, most pathogens are immediately detected by various recognition systems and are destroyed by induction of defense effectors like antimicrobial peptides. Toll-like receptors, nucleotide-binding and oligomerization domain-like receptors and scavenger receptor cysteine-rich proteins represent archetypes of the innate immune receptors, which mediate the complex interaction between the host and microbiota at the interface of epithelial barriers. In this review, we will use knowledge gained from marine invertebrates as a paradigm to describe how this constant molecular crosstalk within the holobiont, i.e. the animal with all its associated microorganisms, contributes to epithelial homeostasis, immunological integrity and maintenance of the resident microbial diversity.
Influence of Prior Activity (Warm-Up) and Inspiratory Muscle Training upon Between- and Within-Day Reliability of Maximal Inspiratory Pressure Measurement
Authors: Lomax M. , McConnell A.K.
Published: April 2009

Background: A specific inspiratory muscle ‘warm-up’ (IWU) prior to assessment of maximal inspiratory mouth pressure (PImax) may reduce the number of measurements required to obtain reproducible, representative estimates of PImax. The influence of inspiratory muscle training (IMT) upon this phenomenon is unknown. Objective: Compare the impact of an IWU on the between- and within-day reliability of PImax before and after IMT. Method: Eight participants were assessed on 4 separate occasions: 2 trials preceded IMT and 2 followed it. At each assessment, the highest of 3 initial efforts was recorded as the pre-IWU value (PI). The highest of 9 subsequent efforts that followed 2 sets of 30 breaths at 40% PI was recorded as PImax. Following 4 weeks of IMT, the trials were repeated. Results: IWU increased PI by 11–17% (p ≤ 0.01), irrespective of IMT status. After IWU, 5–6 efforts were required to determine PImax, irrespective of IMT status. PImax was similar between the 2 trials before IMT and the 2 trials after IMT (p ≥ 0.05), and was 21% higher after IMT (p ≤ 0.01). The coefficient of variation was excellent before and after IWU, both before (1.9 and 0.6%, respectively) and after IMT (1.1 and 0.3%, respectively). Limits of agreement and sample sizes for effect sizes ≤10% were substantially smaller after IWU in all trials. Conclusions: (1) IWU enhances the between-day reliability of PImax measurement, and this is unaffected by IMT, and (2) judgements regarding acceptability in relation to PImax reliability should be made in relation to analytical goals and we present data to facilitate this.
Hair Follicle Stem Cells: Characteristics and Possible Significance
Authors: Reynolds Amanda J. , Jahoda Colin A.B.
Published: April 2009

All four of the principle dermal and epidermal cell types from the adult hair follicle (dermal papilla and sheath, germinative epidermal and outer root sheath) can now be grown in culture. The germinative epidermal cells from the source of the hair fibre appear to be the most visually distinctive of these populations, but all four can be morphologically, synthetically and behaviourally distinguished from general interfollicular skin cells. The germinative population also most obviously exhibit many classical stem cell attributes, but the interactive and inductive capabilities of all of the cell types, in addition to their multipotential natures, highlights that they all share an intriguing level of developmental flexibility.
Vellus Hair Follicle-Derived Keratinocyte Culture: A New Experimental Model in Human Hair Research
Authors: Blume Ulrike , Schön Michael P. , Zouboulis Christos C. , Detmar Michael , Orfanos Constantin E.
Published: April 2009

Biological and biochemical mechanisms of hair growth are difficult to study in vivo; therefore the development of in vitro models is of great interest. Today, we have of our disposal reliable techniques to cultivate cell populations and entire components of terminal hair follicles; however, in vitro culture models for cells derived from vellus hair follicles have not yet been established. In this study, we present a technique for cultivating vellus hair follicle-derived keratinocytes (VHK) and we present first findings on their characterization. Primary cultures of VHK were obtained as outgrowths of cultured intact vellus hair follicles prepared by microsurgical means after incubation of full-thickness human skin with dispase. (1) VHK cultures reached confluency after 16–20 days and 3–4 subcultures were possible. (2) VHK were characterized as epithelial cells by light and electron microscopy. (3) A multi-layered stratified epithelium with 8–10 cell layers was observed by electron microscopy presenting abundant keratinos-omes in individual cells in contrast to outer root sheath keratinocytes. (4) Synthesis studies of two glycoproteins characteristic for undifferentiated (gp 38) and for differentiated (gp 80) keratinocytes revealed higher synthesis levels for gp 80 and lower levels for gp 38 in VHK as compared to normal epidermal keratinocytes in vitro. These findings suggest a distinct morphologic and differentiation pattern of VHK in culture. This experimental model provides a new tool to study mechanisms of hair growth regulation in vellus hair follicles and to compare them to those of terminal hair follicles.
Organotypic Cocultures as Models to Study Cell-Cell and Cell-Matrix Interactions of Human Hair Follicle Cells
Authors: Limat Alain , Hunziker Thomas , Breitkreutz Dirk , Fusenig Norbert E. , Braathen Lasse R.
Published: April 2009

In the hair follicle complex interactions of specialized epithelial and mesenchymal cells as well as extracellular components are crucial for regulation of proliferation and differentiation. In order to mimic this situation in vitro, techniques to cultivate follicular cells such as outer root sheath (ORS) cells, hair matrix cells (HMC) and hair papilla cells (HPC) were developed. Human dermal fibroblasts (HDF) and HPC markedly enhanced proliferation of ORS cells when cocultured spatially separated in a two-chamber system, which was more pronounced with postmitotic than with mitotic mesenchymal cells. In organotypic cocultures of ORS cells on HDF- or HPC-populated collagen gels lifted at the air-medium interface, stratified epithelia developed largely reminiscent of the epidermis. The morphology was well structured and differentiation markers were expressed (e.g. suprabasal keratins, filag-grin, involucrin, basement membrane components). Both proliferation and differentiation were dependent on the presence of HDF or HPC. When grown embedded in extracellular matrix (Matrigel) without HDF, ORS cells formed large spheroids with inward directed differentiation. Also herein HDF or HPC sustained both cell growth and balanced, epidermis-type differentiation. While in organotypic cocultures with HDF, HMC also organized into stratified epithelia, epidermis-type stratification was prevented by HPC. Similarly, in the presence of HDF, HMC in Matrigel formed keratinizing spheroids, whereas this was largely suppressed in the presence of HPC. However, hair-type differentiation was not observed, suggesting a crucial role of other yet unknown components or of the surrounding matrix.
Induction of Intercellular Adhesion Molecule 1 Expression on Normal Human Keratinocytes by Retinoic Acid: Comparison of Cultured Keratinocytes and Skin Explants
Authors: Gatto H. , Viac J. , Richard M.H. , Lizard G. , Charveron M. , Schmitt D.
Published: April 2009

As retinoic acid (RA, all trans) induces irritant reactions when applied topically to skin, we wondered whether it may be involved in the activation state of keratinocytes through ICAM-1 induction. Human skin explants and cultured keratinocytes were treated by RA and /or interferon-Γ (IFNΓ) at different concentrations during 24, 48 and 72 h. ICAM-1 expression was examined and quantified by immunohistochemistry, in situ, on cutaneous frozen sections and in cultured keratinocytes by flow cytometry analysis. Expression of mRNA was checked by Northern blot hybridizations using an oligonucleo-tide probe. Our results indicate: (1) the absence of spontaneous ICAM-1 expression by normal human keratinocytes both in skin explants and in cultures; (2) an ICAM-1 -induced expression after 48 h of treatment by RA concentrations > 10-6M; this induction is dose- and time-dependent; in skin explants, ICAM-1 is occasionally observed on foci of epidermal cells; this protein induction is correlated with transcript expression in cultured keratinocytes; and (3) a synergistic effect of RA and IFNΓ (5 IU/ml) on the percentage of ICAM-1 -positive cells and the level of expression of the protein. These findings indicate that RA, in a therapeutical range of concentrations, can induce or stimulate ICAM-1 expression in normal human keratinocytes. This may in part explain the erythematous reaction observed in vivo after topical applications of RA which may be considered as a mediator of keratinocyte activation.
Comparison of Thymoxamine Permeation between Hairless Rat and Horse Penile Mucous Membrane Using an in vitro Diffusion Model
Authors: Neau B. , Lozano P. , Gomond P. , Roux J. , Grislain L. , Lambrey B.
Published: April 2009

Moxisylyte (or thymoxamine) administered intracavernously is known to improve erection in organically impotent patients. Prior to drug administration by percutaneous route, we have to define its in vitro permeation parameters after application of thymoxamine on both rat skin and horse penile mucous membrane. 24 h after drug application, the percentages of thymoxamine which diffused through the penile mucous and the rat skin were 88 and 75%, respectively. Thymoxamine flux varied according to the biological membrane tested. With regard to the penile mucous membrane, a maximal flux (1,774 nmol·h-1·cm-2) was observed 2.5 h after drug application, whereas for the rat skin a maximal flux (657 nmol·h-1·cm-2) was noted at 3.5 h. Thymoxamine flux decreased rapidly in the penile mucous membrane. This decrease was slower when thymoxamine penetrated the rat skin; the difference could be due to a different morphology of the tested biological membranes. In contrast to the rat skin, the external keratinized layer was absent in the penile mucous membrane. In conclusion, the ability of thymoxamine to penetrate easily and rapidly the biological membrane, and particularly the penile mucous membrane, suggests that thymoxamine could reach the pharmacological target represented by the corpus cavernosum of the penis.
Plasma Concentrations after Three Different Doses of Topical Isotretinoin
Authors: Santana D. , Bun H. , Joachim J. , Durand A. , Reynier J.P.
Published: April 2009

The aim of the study was to investigate the plasma concentrations of isotretinoin and its metabolites, at three doses and after single and multiple topical applications of isotretinoin gel (0.05%) in hairless rats. We used a highly sensitive HPLC method for simultaneous determinations of these compounds, with a detection limit of 2 ng/ml in plasma. Isotretinoin and its metabolites were detected after single and multiple cutaneous applications of overdosing (2,000 mg) of isotretinoin gel up to 24 h after the single dose and after the last dose. The plasma concentrations of these compounds were below the limit of quantification in all the animals at all times for the 200- and 20-mg doses.
Role of Transepidermal and Transfollicular Routes in Percutaneous Absorption of Steroids: In vitro Studies on Human Skin
Authors: Hueber F. , Schaefer H. , Wepierre J.
Published: April 2009

Percutaneous absorption theoretically comprises two components: the transepidermal and the transfollicular routes. The aim of the present work was to confirm this hypothesis in the human skin by comparing the in vitro percutaneous absorption of four steroids through scar skin without hair follicles and sebaceous glands and through normal adjacent skin from abdominal or mammary plasties. In all cases, the absorption of the four steroids was significantly higher in normal skin than in scar skin. The cumulative percentages of progesterone and testosterone after 8 h of application were, respectively, 3.1- and 2.4-fold higher in normal skin than in scar skin. After 24 h of application, the cumulative percentages of estradiol and hydro-cortisone were 1.7- and 2.4-fold higher in normal skin than in scar skin. At the end of the experiments, the quantities of drugs remaining in the skin after 8 or 24 h of application were the same in normal skin and in scar skin except for progesterone for which they were 2-fold greater in normal than in scar skin. In each case, a histological characterization of the scar skin was made in comparison with the normal adjacent skin. The main modifications observed on scar skin were the following: absence of hair follicles and sebaceous glands, thinning of the collagenous fibers with parallel orientation to the dermoepidermal junction and decrease in the number or disappearance of the elastic fibers. These experiments confirmed that human skin appendages, hair follicles and sebaceous glands, constitute a route of penetration for steroids and thus probably for other chemicals of similar molecular weight and properties.
Antioxidant Inhibition of Skin Inflammation Induced by Reactive Oxidants: Evaluation of the Redox Couple Dihydrolipoate/Lipoate
Authors: Fuchs Jürgen , Milbradt Rainer
Published: April 2009

Reactive oxygen species play an important role in mediating skin inflammation, and antioxidants may provide protection. We investigated the anti-inflammatory activity of natural antioxidants, such as superoxide dismutase, catalase, trolox (a water-soluble tocopherol analog) and the redox couple dihy-drolipoate/lipoate in skin. Furthermore we compared the anti-inflammatory potency of natural R and racemic dihydroli-poate, as well as R and S lipoate. Skin inflammation in hairless mice was induced by intradermal injection of the hydrogen peroxide producing enzyme glucose oxidase (GOD) or by topical application of the prooxidant drug anthralin. Intradermal injection of the antioxidants inhibited skin inflammation caused by GOD (catalase, dihydrolipoate) and anthralin (trolox, superoxide dismutase, dihydrolipoate). There was no statistically significant difference between the anti-inflammatory activity of the natural R and racemic dihydrolipoate. R or S lipoate did not inhibit skin inflammation when injected intradermally. In feeding experiments, however, R lipoate significantly inhibited GOD-mediated skin inflammation, while S lipoate was only marginally protective. We conclude that (1) several natural antioxidants such as catalase, superoxide dismutase and dihydrolipoate have anti-inflammatory properties in dermatitis induced by reactive oxidants, (2) lipoate (oxidized dihydrolipoate) has skin anti-inflammatory activity when administered orally and (3) naturally occurring R lipoate is a more potent anti-inflammatory agent than the non-physiological S lipoate.
Effects of Oral Administration of Acitretin on Rat Liver Microsomal Phospholipids, P-450 Content and Monooxygenase Activities
Authors: Tsambaos D. , Bolsen K. , Georgiou S. , Kalofoutis A. , Goerz G.
Published: April 2009

Doses of 3 and 10 mg/kg/day acitretin were orally administered to female Wistar rats over a period of 6 weeks. Phospho-lipid classes, P-450 content, aminopyrine-N-demethylase (ADM) and 7-ethoxyresorufin-O-deethylase (7-ERO-D) activities were determined in the liver microsomes of the treated animals. Both dosages caused statistically significant alterations in rat liver microsomal phospholipid composition which may be associated with changes in the metabolic activity, ionic transport, cell-cell interaction and other processes of the hepatic cellular components. Furthermore, statistically significant alterations of P-450 isozyme activities were induced by both dosages. Our data suggest a possible interaction of acitretin with other drugs and endogenous substances metabolized by these enzyme systems.
Minoxidil Sulfation in the Hair Follicle
Authors: Baker C.A. , Uno H. , Johnson G.A.
Published: April 2009

The in vivo model which may be the most accurate for the ability to predict hair growth in humans, and which was utilized in the preclinical development of minoxidil, is the adult stumptailed macaque. Previous reports have suggested that the enzyme activity which accounts for the activation of minoxidil, i.e., minoxidil sulfotransferase, is present in skin. We have demonstrated that scalp skin from the stumptailed macaque contains minoxidil sulfotransferase activity, and further with dissection of that scalp skin into epidermis, dermis and hair follicle, most of sulfotransferase activity was present in the follicle. Sulfotransferase activity in the hair follicle in freeze-dried scalp skin sections from 9 stumptailed macaques ranged from 47 to 84% of the total (mean 61 ± 12%). Much less minoxidil sulfotransferase activity was measured in the epidermis (mean 18 ± 11%, with a range of 2–37%) and the dermis (mean 21 ± 8%, with a range of 4–3 5%) of these scalp sections. These results indicate that the scalp skin from the stumptailed macaque contains minoxidil sulfotransferase activity and this activity is largely localized in the hair follicle which may account for its ability to stimulate hair growth in this animal model.
Treatment of Psoriasis with Anthrones – Chemical Principles, Biochemical Aspects, and Approaches to the Design of Novel Derivatives
Authors: Wiegrebe Wolfgang , Müller Klaus
Published: April 2009

Antipsoriatic anthrones are probably the most commonly used topical agents in the treatment of psoriasis. There is growing evidence that the biochemical basis for their mechanism of action at the molecular level is related to their redox activity leading to the production of active oxygen species, which include singlet oxygen, superoxide anion radical, and hydroxyl radical. These species are involved in a variety of oxidative effects affecting cellular targets that have been implicated both in the mode of action and the skin-irritating properties of antipsoriatic anthrones: interaction with DNA, inhibition of various enzyme systems associated with cell proliferation and inflammation, such as glucose-6-phosphate de-hydrogenase and 5-lipoxygenase, and destruction of membrane lipids. Furthermore, the application of this information to the design of novel derivatives is discussed. In particular, compounds with diminished oxygen radical-generating properties have been developed, which may permit a separation of antipsoriatic and inflammatory effects. Some of the novel anthrone analogs which produced significantly less amounts of oxygen radicals than dithranol compared favorably in biological tests with this known antipsoriatic drug as an alternative method of treating psoriasis.
Skin Microdialysis: Detection of in vivo Histamine Release in Cutaneous Allergic Reactions
Authors: Okaham Kayo , Murakami Teruo , Yamamoto Shoso , Yata Noboru
Published: April 2009

In vivo histamine release in cutaneous allergic reactions was chronologically examined using the skin microdialysis technique. Antigen challenge was made in ovalbumin-sensitized guinea pigs 1 h after the implantation of the microdialysis probe. A marked histamine release after intradermal injection of ovalbumin solution was observed in the early phase (up to 40 min). No isolated delayed histamine release was observed thereafter over 8 h. Also, in an atopic volunteer, a marked release of histamine after intradermal injection of mite extract was observed only in the early phase, although erythema and induration at the site of injection were continuously observed in the late phase (up to 4 h). These findings suggest that the skin microdialysis technique is a useful, simple technique for chronological determination of chemical mediators released in the allergic skin in vivo.
Retinoids Can Be Classified according to Their Effects on Vitamin A Metabolism in HeLa Cells
Authors: Stenström Eva , Björklind Carina , Schaaf Berhard , Vahlquist Anders , Törmä Hans
Published: April 2009

Although retinoids may exert their action via binding to nuclear retinoic acid receptors (RARs), other mechanisms of action are not excluded. For example, the anti-acne drug, isotretinoin, lacks affinity for the receptors, but is a very potent inhibitor of endogenous vitamin A metabolism in human epidermal cells. To further extend this observation, we studied the effect of 12 different retinoids on the metabolism of [3H]retinol ([3H]ROH) in HeLa cells, previously shown to produce constant levels of 3,4-didehydroretinol (ddROH). The cells were cultured in the presence of the unlabeled retinoids for 20 h, followed by 4 h incubation with [3H]ROH. The accumulation of [3H]ROH and [3H]ddROH in cellular extracts was analysed by HPLC. Addition of 10-10 to 10-5M of four naturally occurring isomers of retinoic acid caused a 4- to 6-fold increase in [3H]ROH accumulation and an 80% decrease in [3H]ddROH. Addition of synthetic retinoids with a terminal carboxyl (CD270, CD271, CD367 and Ro 13-7410) decreased the [3H]ddROH accumulation with about 70%, but hardly at all affected the accumulation of [3H]ROH. We conclude that cultured HeLa cells appear to be useful for screening retinoids for their effects on vitamin A metabolism showing that a terminal carboxylic acid is a prerequisite for any major effects on metabolism to occur. Whether this effect is due to interaction with RARs or to competitive inhibition of vita-min-A-metabolizing enzymes demands to be studied.
A Critical Comparison of Methods to Quantify Stratum corneum Removed by Tape Stripping
Authors: Marttin E. , Neelissen-Subnel M.T.A. , De Haan F.H.N. , Boddé H.E.
Published: April 2009

Skin surface stripping with adhesive tape has been used to study the barrier function of the stratum corneum. Usually, the amount of stratum corneum removed by stripping is not linearly proportional to the number of strips removed. The generally accepted quantitative method to determine the amount of stratum corneum material on a tape strip is weighing. This method however has certain drawbacks, it is time consuming and laborious because tape strips have to be weighed twice and sometimes it cannot be used to determine concentration profiles in the skin of active substances in topically applied vehicles. In this paper, the accuracy and reliability of an alternative method to determine the amount of stratum corneum removed by tape stripping of the skin was investigated and compared to weighing. It is based on the spectrophotometric examination of the tape. The light absorption by the proteins on the tape is correlated to the weight of the stratum corneum material. This method was found to be easier and faster than weighing, but it was less reliable because the light scattering of the stratum corneum on the tape largely overshadowed the absorption of the proteins. The light scattering showed a linear increase with an increasing amount of material on the tape, but with a large variability, resulting in calibration curves with correlations of 0.8400. However, direct spectroscopic analysis of stratum corneum tape strips has some distinct advantages even if it cannot be used for the exact quantification of stratum corneum proteins. With direct spectroscopic measurements, a tape strip can be laterally examined to inspect its homogeneity. Direct spectroscopic measurements on tape strips might also be employed to investigate the lateral and in-depth distribution of strongly light-absorbing substances in the stratum corneum.
Effect of Fumaric Acid, Its Dimethylester, and Topical Antipsoriatic Drugs on Epidermal Differentiation in the Mouse Tail Model
Authors: Sebök B. , Szabados T. , Kerényi M. , Schneider I. , Mahrle G.
Published: April 2009

Fumaric acid, fumaric acid dimethylester, and the dithranol derivative C4-lactone were studied in the mouse tail test to evaluate their effects on epidermal cell differentiation compared with other topical antipsoriatic drugs, such as betamethasone, calcipotriol, and dithranol. Mouse tails were treated for 2 weeks and longitudinal histological sections prepared of the tail skin. The length of the orthokeratotic regions (stratum granulosum) was measured on 10 sequential scales per tail and expressed as percentage of the full length of the scale. In addition, epidermal thickness was measured and the efficacy of the various compounds evaluated. In comparison to 2% salicylic acid ointment, all tested compounds except fumaric acid significantly (p ≤ 0.05) increased the proportion of the orthokeratotic region. C4-lactone and calcipotriol were less effective than dithranol, fumaric acid dimethylester only moderately influenced cell differentiation, and betamethasone showed the least potent effect. Dithranol was the most potent substance inducing orthokeratosis without increasing epidermal thickness.
Effects of Inflammation on Plasma Extravasation and Mast Cell Response in Normal and Denervated Rat Skin
Authors: Shakhanbeh Jumah , Abo-Galyon Yonis
Published: April 2009

The effects of mild inflammation induced by topical chloroform treatment on plasma extravasation and mast cell response were studied in normal innervated and denervated rat skin. In the absence of inflammation, the reduction in plasma protein extravasation in response to noxious heat was 31.2% in denervated skin compared to the innervated skin. In the presence of inflammation, the reduction in this response was 52.5% in denervated skin compared to the innervated skin. During inflammation, mast cells became abundant, highly degranulated and migrated to the lower dermal tissue forming large aggregations. The ultrastructural observations showed a close anatomical relationship between mast cells and vesicle-containing nerve profiles. These results indicate that repeated topical chloroform treatment of the rat skin induces neurogenic vascular inflammation accompanied by an increase in mast cell response.
Heterogeneity of Human Skin Mast Cells and Human Basophils
Authors: Amon Ulrich , Dieckmann Detlef , Nitschke Martin , von Stebut Esther , Gibbs Bernhard F. , Wolff Helmut H.
Published: April 2009

Skin mast cells and basophilic leukocytes are known as key elements of acute and subacute IgE-mediated immune responses of the skin. The present paper investigated pharmacological aspects of signal transduction pathways of both cell types using activators and inhibitors of protein kinase C (PKC). The nonselective inhibitor K252a suppressed FcεRI-mediated histamine release from basophils and skin mast cells dose-dependently with IC50 values of 0.01 and 0.28 μmol/l. However, preincubation of both cell populations with kinase inhibitors showing in vitro selectivity for PKC (Ro 31-7549, calphostin C, GF 109203X) revealed a distinct modulation of cell response: IgE-mediated mediator release was inhibited only in skin mast cells, whereas in experiments with basophils a concentration-dependent potentiation of exocytosis was observed. Further evidence for heterogenous biochemical signals following activation of both cell types derived from studies with the phorbol ester TPA. With respect to acute and late-phase IgE-mediated skin reactions, we suggest that distinct signal transduction mechanisms at the level of PKC (isozymes) in basophils and skin mast cells might reflect their functional heterogeneity.
Effect of Imidazole Derivatives on Cytochrome P-450 Enzyme Activities in a Reconstructed Human Epidermis
Authors: Cotovio J. , Roguet R. , Pion F.X. , Rougier A. , Leclaire J.
Published: April 2009

We tested the effect of various imidazole derivatives applied topically, on P-450-dependent enzyme activity of a reconstructed epidermis in conditions simulating clinical use. At nontoxic concentrations (determined by a cytotoxicity test based on the reduction of a tetrazolium salt, MTT, by mitochondrial deshydrogenase) econazole and clotrimazole had a biphasic effect on 7-ethoxycoumarin-O-deethylase (ECOD) activity in the epidermis, with induction at low concentrations and inhibition at high concentrations. Dermatological preparations (emulsions, gels) containing imidazole derivatives, which are nontoxic for the epidermis, decreased ECOD activity by about 40% 18 h after topical application. These results are in keeping with in vivo observations after topical application, and stress the value of the reconstructed epidermis for pharmacotoxicological and mechanistic studies of topical agents used in dermatology.
In vitro Study of Percutaneous Absorption, Cutaneous Bioavailability and Bioequivalence of Zinc and Copper from Five Topical Formulations
Authors: Pirot F. , Millet J. , Kalia Y.N. , Humbert Ph.
Published: April 2009

Percutaneous absorption and cutaneous bioavailability of zinc and copper from zinc 2-pyrrolidone 5-carboxylate (ZnPC), zinc oxide (ZnO), zinc sulfate (ZnSO4), copper 2-pyrrolidone 5-carboxylate (CuPC) and copper sulfate (CuSO4) were compared using 5 formulations (3 emulsions and 2 ointments) that were applied topically on human skin in vitro. After application for 72 h, percutaneous absorption of zinc from ointments containing ZnO and ZnSO4 was found to be lower than that from a ZnPC-containing emulsion (0.36 and 0.34 versus 1.60% of applied dose). In the case of copper, the flux after a 72-hour treatment period showed that there had been minimal release from CuPC- and CuSO4-containing formulations (approximately 5 ng/cm2/h). All formulations used in this study effected an increase in zinc and copper concentrations in whole skin and epidermis. Bioequivalence of the 5 formulations based on pharmacokinetic results was assessed, and salt and vehicle effects were discussed.
Regional Variation of Nonimmunologic Contact Urticaria
Authors: Shriner David L. , Maibach Howard I.
Published: April 2009

Background and Design: Benzoic acid (BA) was used to induce nonimmunologic contact irritation in 10 younger (23-47 years old) and 5 older (72-90 years old) healthy volunteers. BA2.5% in petrolatum was applied to 8 locations on the face, neck and volar forearm. Changes in the skin blood flow were monitored using a laser Doppler flowmeter. Also measured at each location were baseline measurements of skin blood flow, transepidermal water loss, stratum corneum hydration, skin surface temperature and skin surface pH. Results: The neck area exhibited the greatest reaction in both age groups while the forearm exhibited the least. At each site tested, the younger group consistently demonstrated greater reactivity to BA. A significant correlation was noted between stratum corneum hydration and irritation. Conclusion: This information provides a basis to further study the frequent poorly understood intolerance of the face to topical formulation.
Immunological Gene Therapy Approaches for Malignant Melanoma
Authors: Bonnekoh Bernd , Bickenbach Jackie R. , Roop Dennis R.
Published: April 2009

Gene therapy approaches pursuing immunological strategies for the treatment of malignant melanoma play major roles in the current efforts to explore the potential benefits of gene transfer technologies for medicine. This may be explained by the nearly complete resistance of advanced metastatic melanoma towards conventional non-surgical treatment modalities, and the particular immunogenicity of melanoma in connection with a presumed immunogene therapeutic ‘field effect’. The latter relates to the potency of the immune system to amplify gene transfer effects that are limited due to the imperfection of the currently available gene delivery systems. The ongoing clinical trials focus predominantly on treatment safety and tolerability rather than efficacy. The corresponding tumor-immunological background is reviewed, focusing on a treatment concept centred on tumor-reactive, cytotoxic CD8+ T effector cells.
Biochemical Studies on the Aging of Rat Tail Tendon
Authors: Robert L. , Derouette S. , Moczar E.
Published: April 2009

The chemical composition of rat tail tendon was determined in rats in different ages from 1 month to 24 months. Total protein and calcium chloride extractable (CTC extract) protein decreases steadily with age and particularly sharply between the 1st and 3rd month of age. Extractable hydroxyproline (soluble collagen) decreases very strongly between the 1st and 3rd month, remains then constant and decreases again between the 17th and 24th month of age. Polymeric collagen (TCA extract) increases sharply between the 1st and 3rd month of age and shows then relatively little changes with a slight decrease only from the 3rd month to the 24th month. Structural glycoproteins (urea-extract) decrease from the 1st to the 10th month and remain then relatively constant. Their relative ratio to total protein of the tendon does not change with age. Total hexose decreases from the 1st to the 3rd month of age as does hexose and hexosamine in a 0.9% sodium chloride extracted tendon residue. The ratio of galactose, glucose, mannose and xylose or fucose changes also between the 1st to the 3rd month: glucose and mannose decrease with respect to galactose and remain then constant. Xylose or fucose continue to decrease up to the 24th month. Lysine derivatives determined by high voltage electrophoresis do not show this age change. Lysine, hydroxylysine-glycosides, remain in a constant ratio of 1.0 to 0.3 to 0.06. Only trace amounts of hydroxylysine-galactoside are present in rat tail tendon collagen, nearly all of the hydroxylysine linked hexoses are present as glucosido-galactoside. Two unknown spots observed on high voltage electrophoresis of alkaline hydrolysates of rat tail tendon collagen correspond probably to cross-link amino acids and show also a constant ratio to lysine. These results indicate that certain components of rat tail tendon change with age, others do not. Strongly decreasing components are freshly synthesised collagen and some glycoproteins. No age change was observed in the ratio of hydroxylysine linked glycosides as well as in the ratio of structural glycoproteins to total proteins. Some of these results are similar to those which were obtained on chick embryo corneas [15]. There also we observed a decrease of structural glycoproteins simultaneously with an increase of the collagen content of the corneas.
Differential Accumulation of Lipofuscin Pigment in Cerebral Cortex of Rat
Authors: Brizzee K.R. , Cancilla P.A.
Published: April 2009

A comparison of the amount and distribution of lipofuscin pigment in neurons of cerebral cortex in prenatally X-irridiated (90 r) and control aged rats was carried out in areas 3 and 17. The proportion of the neuron somata occupied by the pigment bodies, as determined through the application of the ‘random-hit’ principle in phase-fluorescence microscope studies, was not significantly different in irradiated and control brains in either cortical area. However, the amount of pigment was greater in neurons of area 3 than those of area 17 in both irradiated and control animals. Ultrastructural studies of cerebral cortical tissues in area 3 revealed no abnormalties in neurons or glia of irradiated as compared with control rats.
Chemische Spannungsänderungen von Kollagenfasern
Authors: Hofecker G. , Moser P. , Verzár F.
Published: April 2009

The collagen fibers of tendons contract with considerable force (tension) in concentrated NaCIO4 solution. The covalent crosslink originates from lysinoaldehyde. Its tension becomes activated when the hypertonic solution removes the latch action of the intramolecular waterbonds. It is therefore reversible in isotonic solution. The tension decreases on repetition till it finally disappears completely when all aldehyde groups are oxydised to the Schiff basealdimine: at this stage collagen becomes insoluble in water.
Enzyme Patterns in Young and Old Mouse Livers and Lungs
Authors: Wilson Patricia D.
Published: April 2009

Enzyme assays in young (3–10 days), adult (6 months), middle-aged (18 months) and old (30 months) male and female C57 and C3H (6 and 12 months) mouse livers and lungs revealed complex patterns of change. Alkaline phosphatase, acid phosphatase, β-glucuronidase, G6PDH, LDH, SDH, cytochrome oxidase, glucose-6-phosphatase, 5′-nucleotidase, glycogen phosphorylase, phosphoglucomutase, ATPase and NAD dia-phorase were measured. In livers of males glycogen phosphorylase was unchanged; acid phosphatase and phosphoglucomutase increased; and glucose-6-phosphatase decreased with age. In livers of females similar patterns of change were found except that 5′-nucleo-tidase was constant; ATPase increased with age. In lungs of males glycogen phosphorylase was unchanged, alkaline phosphatase and phosphoglucomutase increased while acid phosphatase and NAD diaphorase decreased with age. In lungs of females many enzymes showed a different pattern. Acid and alkaline phosphatases, G6PDH, LDH and 5′-nucleotidase were constant and ATPase increased with age. Many enzymes showed either a high peak of activity at 18 months or a decrease in activity with age until 18 months followed by an increase. Light and electron microscope histochemistry showed no changes in enzyme localisation with age. The most common quantitative changes with age were found in the mitochondrial enzymes SDH which showed peak activity at 18 months and LDH which showed peak activity at 6 months.
An Age-Dependent Determination of Lysosomal Enzyme Activities, as well as the Measurements of the Incorporation of 14-C-Proline and 14-C-GIucosamine in a Subcutaneously Implanted Polyether Sponge
Authors: Platt D. , Rühl W.
Published: April 2009

Synthetic sponge (polyether) was implanted in the subcutis of male albino rats of 3 age groups: 6 weeks old, 9 months old and 20–22 months old. Morphological and biological examinations were made on the granulation tissue which migrated into it. As parameters for the inter-cellular catabolic process, the activity measurements of the β-glucuronidase, β-acetylglucosaminidase, cathepsin D and a collagen catabolic enzyme were conducted. The incorporation rate of 14C-glucosamine and 14C-ρroline served as an indicator for the synthesis mechanisms. In addition to this, the DNA content of the sponge was determined. The measurements of all the above-named parameters were made 14, 21 and 30 days after the implantation, on the sponge implanted in the paravertebral subcutis. The results demonstrate that, depending on the duration of implantation as well as on the age of the animal, distinct alterations of the examined parameters take place. A correlation of the various parameters to one another could not be established. The findings were discussed in relation to those found in the literature.