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1

Electronic Resource

ELIAS, PETER M. ; FEINGOLD, KENNETH R.

Oxford, UK : Blackwell Publishing Ltd

Annals of the New York Academy of Sciences 548 (1988), S. 0

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ISSN: 1749-6632

Source: Blackwell Publishing Journal Backfiles 1879-2005

Topics: Natural Sciences in General

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1111/j.1749-6632.1988.tb18788.x

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2

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Comprehensive analysis of the gene encoding filaggrin uncovers prevalent and rare mutations in ichthyosis vulgaris and atopic eczema (2007)

Sandilands, Aileen ; Terron-Kwiatkowski, Ana ; Hull, Peter R ; [et al.]

[s.l.] : Nature Publishing Group

Nature genetics 39 (2007), S. 650-654

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ISSN: 1546-1718

Source: Nature Archives 1869 - 2009

Topics: Biology , Medicine

Notes: [Auszug] We recently reported two common filaggrin (FLG) null mutations that cause ichthyosis vulgaris and predispose to eczema and secondary allergic diseases. We show here that these common European mutations are ancestral variants carried on conserved haplotypes. To facilitate comprehensive analysis of ...

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1038/ng2020

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3

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Localization of calcium in murine epidermis following disruption and repair of the permeability barrier (1992)

Menon, Gopinathan K. ; Elias, Peter M. ; Lee, Seung Hun ; [et al.]

Springer

Cell & tissue research 270 (1992), S. 503-512

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ISSN: 1432-0878

Keywords: Epidermis ; Permeability ; Calcium ions ; Ionic localization ; Mouse (hr/hr)

Source: Springer Online Journal Archives 1860-2000

Topics: Biology , Medicine

Notes: Summary Perturbation of the cutaneous permeability barrier results in rapid secretion of epidermal lamellar bodies, and synthesis and secretion of new lamellar bodies leading to barrier repair. Since external Ca2+ significantly impedes the repair response, we applied ion capture cytochemistry to localize Ca2+ in murine epidermis following barrier disruption. In controls, the numbers of Ca2+ precipitates in the basal layer were small, increasing suprabasally and reaching the highest density in the stratum granulosum. Barrier disruption with acetone produced an immediate, marked decrease in Ca2+ in the stratum granulosum, accompanied by secretion of lamellar bodies. Loss of this pattern of Ca2+ distribution was associated with the appearance of large Ca2+ aggregates within the intercellular spaces of the stratum corneum. The Ca2+-containing precipitates progressively reappeared in parallel with barrier recovery over 24 h. Disruption of the barrier with tape stripping also resulted in loss of Ca2+ from the nucleated layers of the epidermis, but small foci persisted where the stratum corneum was not removed; in these sites the Ca2+ distribution did not change and accelerated secretion of lamellar bodies was not observed. Following acetone-induced barrier disruption and immersion in isoosmolar sucrose, the epidermal Ca2+ gradient did not return, and both lamellar body secretion and barrier recovery occurred. However, with immersion in isoosmolar sucrose plus Ca2+, the epidermal Ca2+ reservoir was replenished, and both secretion of lamellar bodies and barrier recovery were impeded. These results demonstrate that barrier disruption results in loss of the epidermal Ca2+ reservoir, which may be the signal that initiates lamellar body secretion leading to barrier repair.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00645052

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4

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Microwave incubation improves lipolytic enzyme preservation for ultrastr uctural cytochemistry (1997)

Rassner, Ulrich A. ; Crumrine, DEBRA A. ; Nau, Patricia ; [et al.]

Springer

Journal of molecular histology 29 (1997), S. 387-392

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ISSN: 1573-6865

Source: Springer Online Journal Archives 1860-2000

Topics: Biology , Medicine

Notes: Abstract Standard methods for the ultrastructural detection of lipase and sphingomyelinase activities in the skin result in considerable loss of structural preservation, often interfering with accurate delineation of enzyme localization in association with specific organelles. Moreover, poor preservation occurs, even after extensive aldehyde prefixation, owing to the prolonged incubation times needed to detect residual enzyme activity, which often require non- physiological conditions. A modified incubation protocol is described here, which uses microwave irradiation in conjunction with drastically shortened incubation times, resulting in both superior ultrastructural preservation and excellent localization in mammalian epidermis. This method should be useful generally not only for the study of lipase localization in skin, but also in conjuction with the cytochemical detection of a variety of enzymes in various types of tissue

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1023/A:1026438917856

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5

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Sonophoresis. II. Examination of the Mechanism(s) of Ultrasound-Enhanced Transdermal Drug Delivery (1992)

Bommannan, D. ; Menon, Gopinathan K. ; Okuyama, Hirohisa ; [et al.]

Springer

Pharmaceutical research 9 (1992), S. 1043-1047

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ISSN: 1573-904X

Keywords: sonophoresis ; percutaneous absorption ; penetration enhancement ; ultrasound ; skin barrier function ; electron microscopy ; lanthanum hydroxide

Source: Springer Online Journal Archives 1860-2000

Topics: Chemistry and Pharmacology

Notes: Abstract We have shown previously that high-frequency ultrasound (sonophoresis) can significantly enhance the transdermal delivery of a topically applied drug in vivo and that the augmentation of transport was caused by the action of the ultrasound on the skin. However, these earlier experiments did not reveal (i) the mechanism of sonophoresis, (ii) the pathway of drug permeation under the influence of ultrasound, and (iii) any potentially detrimental effects of the enhancement procedure on skin structure and morphology. In the study reported here, these three key issues have been addressed using electron microscopy to follow the penetration of an electron-dense, colloidal tracer (lanthanum hydroxide; LH). Experiments have again been performed using the hairless guinea pig animal model. Colloidal LH suspensions were applied to skin sites, which were then immediately exposed to ultrasound (at 10 or 16 MHz) for 5 or 20 min. Passive transport of LH under identical conditions (but without ultrasound) provided the control measurements. Tissue processing after the treatment periods utilized standard electron microscopy staining procedures. We found the following: (1) LH does not permeate the skin by passive diffusion; under the influence of ultrasound, on the other hand, it penetrates through the stratum corneum (SC) and the underlying viable epidermal cell layers via an apparently intercellular route. (2) LH transports through the epidermis to the upper dermis, even after only 5 min of ultrasound treatment, a remarkable and unexpected finding. (3) The SC and the cells of the epidermis do not appear to be adversely affected by either (a) ultrasound treatment at 10-MHz frequency (5- or 20-min exposure) or (b) 5 min of sonophoresis at 16 MHz. However, a 20-min treatment with ultrasound at 16 MHz resulted in altered cellular morphology compared to the passive control. The distribution of the tracer in the latter experiments was nonuniform and suggested that cavitational effects may have contributed to the adverse observations. Overall, the results demonstrate that exposure of the skin to ultrasound can induce the considerable and rapid facilitation of LH transport via an intercellular route. Prolonged exposures at high frequencies, however, can alter epidermal morphology, leading us to pose further questions pertaining to the duration and reversibility of ultrasound action on skin.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1023/A:1015806528336

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6

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Lipid content and metabolism of human keratinocyte cultures grown at the air-medium interface (1988)

Williams, Mary L. ; Brown, Barbara E. ; Monger, Daniel J. ; [et al.]

New York, NY [u.a.] : Wiley-Blackwell

Journal of Cellular Physiology 136 (1988), S. 103-110

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ISSN: 0021-9541

Keywords: Life and Medical Sciences ; Cell & Developmental Biology

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Biology , Medicine

Notes: The differentiation of human keratinocytes in most culture systems is incomplete; e.g., lamellar bodies, the characteristic lipid-delivery organelles of epidermis, are not present. Moreover, their lipid profile does not reflect the distinctive composition found in cornifying epidermis. In contrast, keratinocytes that grow at an air-medium interface exhibit more complete differentiation. In this study, we compared the elaboration of lamellar bodies, the lipid content, and the lipid metabolism of human keratinocytes, cultured both under standard immersed conditions and after lifting to an air-medium interface. Whereas submerged cultures neither elaborated lamellar bodies nor displayed a lipid distribution characteristic of cornifying epidermis, lifted cultures displayed advanced cornification, elaborated lamellar bodies which were deposited in intercellular domains, and a lipid profile more typical of cornifying epidermis. Moreover, lipid biosynthesis was 5-10-fold more active in lifted than in immersed cultures, and was not inhibited by exogenous lipoproteins. These findings are consistent with recent studies that demonstrate both high rates of lipogenesis in differentiating layers of the epidermis as well as autonomy of lipogenesis from the influence of circulating lipoproteins. Thus, the lipid content and metabolism of human keratinocyte cultures, grown at an air-medium interface, demonstrate features that simulate the epidermis.

Additional Material: 5 Ill.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1002/jcp.1041360113

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7

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Free sterol metabolism and low density lipoprotein receptor expression as differentiation markers of cultured human keratinocytes (1987)

Williams, Mary L. ; Mommaas-Kienhuis, Anne-Marieke ; Rutherford, Suzanne L. ; [et al.]

New York, NY [u.a.] : Wiley-Blackwell

Journal of Cellular Physiology 132 (1987), S. 428-440

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ISSN: 0021-9541

Keywords: Life and Medical Sciences ; Cell & Developmental Biology

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Biology , Medicine

Notes: In contrast to most tissues, epidermis and its derivatives appear to lack low density lipoprotein (LDL) receptors and exhibit sterologenesis rates unaffected by circulating lipoprotein (LP) cholesterol content. Since LDL receptors have been demonstrated in both cultured squamous cell carcinoma cells and human foreskin keratinocytes, when maintained in low-calcium media, LDL receptor expression may be related to keratinocyte differentiation. We compared receptor binding and internalization of LDL-gold in normal keratinocytes at different stages of growth at physiological calcium concentrations (early, 3-5 days; preconfluent, 6-10 days; postconfluent, 12-17 days), and correlated receptor expression with sterologenesis in LP-replete vs.-depleted media. Whereas in early cultures about 60% of sterologenesis was LP dependent, this fraction declined in preconfluent and confluent cultures despite continued culture growth and little decline in total sterologenesis. Accordingly, LDL receptors were most evident in early cultures, declining in preconfluent cultures in parallel with the decrease in LP-dependent sterol synthesis. In contrast, sterologenesis in human foreskin fibroblasts was profoundly influenced by exogenous LP at all stages of confluence; total and LP-dependent sterologenesis declined in parallel with growth cessation. These studies represent the first demonstration that normal keratinocytes express functional LDL receptors at physiologic calcium concentrations. Moreover, they demonstrate that LDL receptor expression in keratinocytes, in contrast to fibroblasts, can only in part be attributed to growth requirements. Instead, loss of LDL receptor expression serves as a distinctive marker of keratinocyte differentiation and may reflect the specific functional requirements of the epidermis in vivo.

Additional Material: 8 Ill.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1002/jcp.1041320305

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8

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Biochemical and morphological characterization of growth and differentiation of normal human neonatal keratinocytes in a serum-free medium (1988)

Pillai, Sreekumar ; Bikle, Daniel D. ; Hincenbergs, Mara ; [et al.]

New York, NY [u.a.] : Wiley-Blackwell

Journal of Cellular Physiology 134 (1988), S. 229-237

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ISSN: 0021-9541

Keywords: Life and Medical Sciences ; Cell & Developmental Biology

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Biology , Medicine

Notes: Growth and differentiation of keratinocytes in a serum-free medium (keratinocyte growth medium of KGM) was studied and compared to that under conditions in which serum and feeder cell layers were used. Cells were grown in KGM containing 0.1 mM calcium (KGM/low calcium), KGM containing 1.2 mM calcium (KGM/normal calcium), or Dulbecco's modified Eagles medium containing 5% fetal calf serum and 1.8 mM calcium in presence of mitomycin treated 3T3 M cells (DMEM/5% FCS). Plating efficiency and rate of growth were similar in the three media till confluence. In postconfluent cultures, protein and DNA content of cells attached to the plate in KGM/low-calcium dishes decreased as an increased number of cells were shed into the medium. Cell shedding was much less evident in the presence of normal calcium. Cells grown in KGM/low calcium had a higher rate of cell proliferation (3H-thymidine incorporation into cellular DNA) than cells grown in normal calcium. Transglutaminase activity, involucrin content, and cornified envelope formation were greatest in cells grown in KGM/normal calcium, intermediate in cells grown in DMEM/5% FCS, and least in cells grown in KGM/low calcium. Keratin profiles from cells grown in KGM/low calcium showed a lower percentage of high molecular weight bands compared to the keratin profiles from cells grown in the presence of normal calcium. Keratinocytes in KGM/low calcium grew as a monolayer of cuboidal cells with few features of differentiation, whereas cells grown in KGM/normal calcium stratified into multilayered islands (3-5 layers) surmounted by 2-4 layers of enucleated cells with thickened cornified envelopes. Cells grown in KGM/normal calcium also contained tonofilaments and lamellar bodies unlike cells grown in KGM/low calcium. Cells grown in DMEM/5% FCS also formed stratified layers comparable to cells grown in KGM/normal calcium but lacked cornified cells, keratohyalin granules, tonofilament bundles, and lamellar bodies. These studies indicate the usefulness of serum-free conditions for the culture of human keratinocytes and confirm the importance of extracellular calcium in keratinocyte differentiation.

Additional Material: 6 Ill.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1002/jcp.1041340208

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9

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Localization and quantitation of calcium pools and calcium binding sites in cultured human keratinocytes (1993)

Pillai, Sreekumar ; Menon, Gopinathan K. ; Bikle, Daniel D. ; [et al.]

New York, NY [u.a.] : Wiley-Blackwell

Journal of Cellular Physiology 154 (1993), S. 101-112

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ISSN: 0021-9541

Keywords: Life and Medical Sciences ; Cell & Developmental Biology

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Biology , Medicine

Notes: Calcium plays a crucial role in regulating the growth and differentiation of cultured keratinocytes. However, the mechanism(s) of this regulation is not clear. Prior studies have shown that intracellular free calcium (Cai) increases with keratinocyte differentiation. In this study, in order to evaluate the role of cytosolic free calcium and organelle-bound calcium in keratinocyte differentiation, we quantitated and localized calcium pools in keratinocytes, utilizing the fluorescence probe indo-1 and ion-capture cytochemistry, respectively. Cai of undifferentiated keratinocytes was 80-120 nM, whereas Cai of differentiated keratinocytes was 200-300 nM depending on the extent of differentiation. The Cai of individual cells in an undifferentiated colony was heterogeneous (60-160 nM) with larger cells displaying higher Cai. Heterogeneity also was observed in the intracellular calcium-containing precipitates in the different layers of stratifying keratinocyte cultures using the cytochemical technique. Calcium precipitates were abundant in the lower cell layers, progressively decreasing apically, with the uppermost layer devoid of precipitates. Calcium-containing precipitates appeared as fine-tocoarse electron-dense granules on the plasma membrane, within the cytosol, mitochondria, nucleus, and vacuolar organelles. Whereas ionomycin in the presence of extracellular calcium increased the amount of intracellular calcium precipitates, EGTA removed calcium precipitates from organelles. Unlike intact epidermis, keratinocytes displayed no extracellular calcium reservoirs. Putative calcium binding sites, visualized by trivalent lanthanum (La) binding, were abundant on cell membranes and desmosomes of basaloid cells, but decreased in the upper cell layers. These studies revealed differences in the distribution of free ionic calcium (as determined by the fluorescence technique) and organelle-bound calcium (as determined by the cytochemical technique). Striking differences were also observed in calcium localization between intact epidermis and cultured epidermal cells. The localization pattern of calcium in cultured keratinocytes may reflect the hyperproliferative state of these cells, as in psoriatic epidermis, and/or the absence of a normal permeability barrier in these submerged cultures. © 1993 Wiley-Liss, Inc.

Additional Material: 7 Ill.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1002/jcp.1041540113

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