| 1. |
- Mørk, Cato, et al.
(författare)
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Microvascular arteriovenous shunting is a probable pathogenetic mechanism in erythromelalgia
- 2000
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Ingår i: Journal of Investigative Dermatology. - : Elsevier BV. - 0022-202X .- 1523-1747. ; 114:4, s. 643-646
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Tidskriftsartikel (refereegranskat)abstract
- Erythromelalgia is a condition consisting of red, warm, and burning painful extremities. Symptoms are relieved by cold and aggravated by heat. A wide variety of etiologic conditions can cause erythromelalgia, but one common pathogenetic mechanism, microvascular arteriovenous shunting, has been hypothesized. The aim of this study was to test this hypothesis. Quantification of skin microvascular perfusion using laser Doppler perfusion imaging and skin temperature at rest and after central body heating was performed in 14 patients with erythromelalgia and 11 controls. Attacks of erythromelalgia were induced in eight patients after heat provocation. In the plantar region of the foot, the location of numerous anatomical arteriovenous shunts, these patients significantly increased the skin perfusion as compared with asymptomatic patients with erythromelalgia and controls. In the dorsal region with few arteriovenous shunts no significant differences between the groups were demonstrated. The results show a relation between clinical symptoms and increased perfusion in the region of numerous anatomical arteriovenous shunts, and support the hypothesis of increased thermoregulatory arteriovenous shunt flow during attacks in primary erythromelalgia.
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| 2. |
- Allhorn, Maria, et al.
(författare)
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Heme-Scavenging Role of alpha1-Microglobulin in Chronic Ulcers.
- 2003
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Ingår i: Journal of Investigative Dermatology. - : Elsevier BV. - 1523-1747 .- 0022-202X. ; 121:3, s. 640-646
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Tidskriftsartikel (refereegranskat)abstract
- Chronic venous ulcers are characterized by chronic inflammation. Heme and iron, originating from blood cell hemolysis as well as extravascular necrosis, have been implicated as important pathogenic factors due to their promotion of oxidative stress. It was recently reported that the plasma and tissue protein alpha1-microglobulin is involved in heme metabolism. The protein binds heme, and a carboxy-terminally processed form, truncated alpha1-microglobulin, also degrades heme. Here, we show the presence of micromolar levels of heme and free iron in chronic leg ulcer fluids. Micromolar amounts of alpha1-microglobulin was also present in the ulcer fluids and bound to added radiolabeled heme. Truncated alpha1-microglobulin was found in the ulcer fluids and exogenously added alpha1-microglobulin was processed into the truncated alpha1-microglobulin form. Histochemical analysis of chronic wound tissue showed the presence of iron deposits, heme/porphyrins in infiltrating cells basement membranes and fibrin cuffs around vessels, and alpha1-microglobulin ubiquitously distributed but especially abundant in basement membranes around vessels and at fibrin cuffs. Our results suggest that alpha1-microglobulin constitutes a previously unknown defense mechanism against high heme and iron levels during skin wound healing. Excessive heme and iron, which are not buffered by alpha1-microglobulin, may underlie the chronic inflammation in chronic ulcers.
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| 3. |
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| 4. |
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| 5. |
- Asumalahti, Kati, et al.
(författare)
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Genetic analysis of PSORS1 distinguishes guttate psoriasis and palmoplantar pustulosis
- 2003
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Ingår i: Journal of Investigative Dermatology. - : Elsevier BV. - 0022-202X .- 1523-1747. ; 120:4, s. 627-632
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Tidskriftsartikel (refereegranskat)abstract
- The PSORS1 locus in the major histocompatibility complex region is the major genetic determinant for psoriasis vulgaris. Within the PSORS1 region reside at least three potential candidate genes for psoriasis susceptibility. Specific allelic variants of the genes HLA-Cw*6, HCR*WWCC, and CDSN*5 are strongly associated with psoriasis vulgaris and are in strong linkage disequilibrium with each other. We have genotyped the three psoriasis vulgaris susceptibility alleles of the PSORS1 locus in two clinical variants of psoriasis (guttate psoriasis and palmoplantar pustulosis) to study whether PSORS1 is also involved in the pathogenesis of these variants. We also asked whether these two clinical subgroups could help us to distinguish the causative gene within the high-risk PSORS1 haplotype. The association of guttate psoriasis with the three PSORS1 susceptibility alleles was similar and even stronger than seen with psoriasis vulgaris. Palmoplantar pustulosis, however, did not show association with any of the three candidate genes at this locus. Finally, no correlation with the age of onset for disease was observed. Our results show conclusively that psoriasis vulgaris and guttate psoriasis have a similar genetic basis for their association to PSORS1, whereas palmoplantar pustulosis appears to be a distinct disorder.
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| 6. |
- Beyer, K., et al.
(författare)
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Association and linkage of atopic dermatitis with chromosome 13q12-14 and 5q31-33 markers
- 2000
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Ingår i: Journal of Investigative Dermatology. - : Elsevier BV. - 0022-202X .- 1523-1747. ; 115:5, s. 906-908
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Tidskriftsartikel (refereegranskat)abstract
- Atopic dermatitis is a chronic inflammatory skin disease that affects 10-20% of the population. Linkage of atopy, asthma, allergic rhinitis, and total serum IgE levels to several different chromosomal regions have been described extensively, but little is known about the genetic control of atopic dermatitis. We tested for the association and linkage between atopic dermatitis and five chromosomal regions: 5q31-33, 6p21.3, 12q15-24.1, 13q12-31, and 14q11.2/14q32.1-32.3. Marker analysis was performed in two Caucasian populations: (i) 192 unrelated German children with atopic dermatitis and 59 non-atopic children from a German birth cohort study (MAS '90), parental DNA was tested in 77 of 192 children with atopic dermatitis, (ii) 40 Swedish families with at least one family member with atopic dermatitis selected from the International Study of Asthma and Allergy in Children. Evidence for linkage and allelic association for atopic dermatitis was observed for markers on chromosome 13q12-14 and 5q31-33.
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| 7. |
- Ekholm, I Elisabeth, et al.
(författare)
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Stratum corneum tryptic enzyme in normal epidermis : a missing link in the desquamation process?
- 2000
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Ingår i: Journal of Investigative Dermatology. - : Nature Publishing Group. - 0022-202X .- 1523-1747. ; 114:1, s. 56-63
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Tidskriftsartikel (refereegranskat)abstract
- Stratum corneum chymotryptic enzyme may be important in desquamation. It has also been suggested that other proteases, especially stratum corneum tryptic enzyme, may be involved. Stratum corneum tryptic enzyme has been purified and its cDNA has been cloned. Results from expression analyses indicate that stratum corneum tryptic enzyme is as skin specific as stratum corneum chymotryptic enzyme. In this work we have produced and characterized antibodies specific for stratum corneum tryptic enzyme. We have also by means of biochemical, immunochemical, and immunohistochemical methods performed studies on stratum corneum tryptic enzyme in normal human epidermis. Antibodies against bacterial recombinant stratum corneum tryptic enzyme were produced and purified by affinity chromatography. Two types of antibodies were obtained: one reacting only with pro-stratum corneum tryptic enzyme and one specific for the catalytically active part of stratum corneum tryptic enzyme. Immunohistochemistry with the antibodies reacting with pro-stratum corneum tryptic enzyme showed a staining pattern similar to stratum corneum chymotryptic enzyme-specific antibodies, i.e., the expression was confined to cornifying epithelia with a need of desquamation-like processes. Extracts of tape strips with superficial human stratum corneum were found to contain precursors as well as active forms of stratum corneum tryptic enzyme and stratum corneum chymotryptic enzyme. The enzymes had maximal activity at pH 8, but both had considerable activity also at pH 5.5. The results were compatible for a role of stratum corneum tryptic enzyme in desquamation. Stratum corneum tryptic enzyme may act in concert with stratum corneum chymotryptic enzyme and/or function as a stratum corneum chymotryptic enzyme-activating enzyme. The presence in normal superficial stratum corneum of precursors as well as of active forms of stratum corneum chymotryptic enzyme and stratum corneum tryptic enzyme, and the activity of both enzymes over a broad range of pH-values, suggest some possible ways by which the desquamation may be regulated.
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| 8. |
- Haak-Frendscho, M, et al.
(författare)
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Histidine decarboxylase expression in human melanoma.
- 2000
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Ingår i: Journal of Investigative Dermatology. - : Elsevier BV. - 0022-202X .- 1523-1747. ; 115:3, s. 345-52
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Tidskriftsartikel (refereegranskat)abstract
- Histamine has been implicated as one of the mediators involved in regulation of proliferation in both normal and neoplastic tissues. Histidine decarboxylase, the only enzyme that catalyzes the formation of histamine from L-histidine, is an essential regulator of histamine levels. In this study, we investigated the gene and protein expression of histidine decarboxylase in melanoma. Reverse transcriptase polymerase chain reaction and in situ hybridization studies of WM-35, WM-983/B, HT-168, and M1 human melanoma cell lines both resulted in positive signals for histidine decarboxylase messenger RNA. A polyclonal chicken antibody was developed against human histidine decarboxylase and protein expression was confirmed by western blot analysis of the cell lysates, revealing a predominant immunoreactive band at approximately 54 kDa corresponding to monomeric histidine decarboxylase. Protein expression of histidine decarboxylase was also shown by flow cytometric analysis and strong punctate cytoplasmic staining of melanoma cell lines. Moreover, both primary and metastatic human melanoma tissues were brightly stained for histidine decarboxylase. When compared with the very weak or no reactions on cultivated human melanocytes both western blot and immunohistochemical studies showed much stronger histidine decarboxylase expression in melanoma cells. These findings suggest that expression of histidine decarboxylase is elevated in human melanoma.
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| 9. |
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| 10. |
- Nowinski, Daniel, et al.
(författare)
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Keratinocytes inhibit expression of connective tissue growth factor in fibroblasts in vitro by an interleukin-1alpha dependent mecanism
- 2002
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Ingår i: Journal of Investigative Dermatology. - : Elsevier BV. - 0022-202X .- 1523-1747. ; 119:2, s. 449-455
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Tidskriftsartikel (refereegranskat)abstract
- The wound healing process concludes with downregulation of fibroblast activity. Clinical observations suggest that the regenerating epidermis suppresses this activity. An important regulator of fibroblast activity is the fibrogenic cytokine connective tissue growth factor. We hypothesized that epidermal keratinocytes may affect fibroblast activity via this cytokine. We demonstrate keratinocyte-mediated suppression of connective tissue growth factor at both the mRNA and protein levels by around 50% or more when fibroblasts were cultured in multiwell plates with keratinocyte cultures in accompanying semipermeable cell culture inserts, or stimulated by keratinocyte-conditioned media. Both basal and transforming-growth-factor-beta1-stimulated levels of connective tissue growth factor were inhibited. A 3 h coculture period with keratinocytes was sufficient to suppress connective tissue growth factor expression by fibroblasts, but the inhibition developed over a time period of around 16 h. The putative keratinocyte-derived factor(s) responsible for these effects was found to be soluble and stable. By analyzing cytokines secreted by keratinocytes we identified interleukin-1alpha as a potent inhibitor of connective tissue growth factor mRNA expression in fibroblasts. Involvement of this cytokine in keratinocyte-mediated connective tissue growth factor suppression was confirmed by using anti-interleukin-1alpha antibodies. Tumor necrosis factor alpha or prostaglandins did not appear to be involved. In conclusion, our results indicate that interleukin-1alpha secretion by keratinocytes provides a mechanism for the downregulation of connective tissue activity during the end-stage of wound healing, when epithelia coverage has developed over the wound area.
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| 11. |
- Pasonen-Seppänen, Sanna, et al.
(författare)
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EGF upregulates, whereas TGF-beta downregulates, the hyaluronan synthases Has2 and Has3 in organotypic keratinocyte cultures: correlations with epidermal proliferation and differentiation.
- 2003
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Ingår i: Journal of Investigative Dermatology. - : Nature Publishing Group. - 0022-202X .- 1523-1747. ; 120:6, s. 1038-1044
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Tidskriftsartikel (refereegranskat)abstract
- Hyaluronan, a major extracellular matrix molecule in the vital cell layers of skin epidermis, has been suggested to support proliferation and migration of keratinocytes, during challenges like wounding and inflammation. An organotypic keratinocyte culture originated from continuous rat epidermal keratinocyte cell line was subjected to the proliferative and antiproliferative growth factors epidermal growth factor and transforming growth factor beta, respectively, to study their influence on hyaluronan synthesis and epidermal morphology. Epidermal growth factor induced a 4-fold increase of epidermal hyaluronan concentration. This was associated with upregulation of the hyaluronan synthases Has2 and Has3, and the hyaluronan receptor CD44. 5-Bromo-2'-deoxyuridine labeling, basal cell height, and the thickness of vital epidermis were increased, reflecting the hyperplastic effects of epidermal growth factor. The expression of keratin 10 and the maturation of filaggrin were inhibited, and epidermal permeability barrier became less efficient, indicating compromised terminal differentiation by epidermal growth factor. In contrast, transforming growth factor beta reduced the content of hyaluronan and the mRNA of Has2 and Has3. At the same time, transforming growth factor beta suppressed keratinocyte proliferation and epidermal thickness, but retained intact differentiation. The results suggest that epidermal hyaluronan synthesis, controlled by epidermal growth factor and transforming growth factor beta through changes in the expression of Has2 and Has3, correlates with epidermal proliferation, thickness, and differentiation.
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| 12. |
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| 13. |
- Szolnoky, G, et al.
(författare)
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A mannose-binding receptor is expressed on human keratinocytes and mediates killing of Candida albicans.
- 2001
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Ingår i: Journal of Investigative Dermatology. - : Elsevier BV. - 0022-202X .- 1523-1747. ; 117:2, s. 205-13
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Tidskriftsartikel (refereegranskat)abstract
- Human keratinocytes are known to kill Candida albicans in vitro, but the mechanism of killing is not yet understood. Here, we demonstrate that spontaneous, ultraviolet-B-light-induced, alpha-melanocyte-stimulating-hormone-induced, and interleukin-8-induced Candida killing by keratinocytes can be inhibited with mannan and mannosylated bovine serum albumin (Man-BSA). A polyclonal goat serum raised against the human macrophage mannose receptor stained suprabasal keratinocytes, but no staining was observed on keratinocytes with a monoclonal antibody (mAb15) specific for the human macrophage mannose receptor. Mannose-affinity chromatography of keratinocyte extract isolated a 200 kDa protein, and on the Western blot the goat antiserum reacted with a 200 kDa protein. In radioligand binding studies, the binding of 125I-Man-BSA to human keratinocytes was inhibited by mannan in a concentration-dependent manner. Analysis of the binding revealed a single class keratinocyte mannose receptor with a KD of 1.4 x 10(-8) M and a Bmax of 1 x 10(4) binding sites per cell. The binding of 125I-Man- BSA to keratinocytes proved to be time-dependent, acid-precipitable, and Ca2+- and trypsin-sensitive. After trypsinization the receptors underwent a rapid recovery at 37 degrees C. These results demonstrate the presence of mannose receptor on human keratinocytes, and its active involvement in the killing of Candida albicans.
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| 14. |
- Virtanen, Marie, et al.
(författare)
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Keratin 4 upregulation by retinoic acid in vivo : a sensitive marker for retinoid bioactivity in human epidermis
- 2000
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Ingår i: Journal of Investigative Dermatology. - : Elsevier BV. - 0022-202X .- 1523-1747. ; 114:3, s. 487-493
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Tidskriftsartikel (refereegranskat)abstract
- Retinoids affect keratinocyte differentiation and modulate the expression of many epidermal proteins, among them cellular retinoic acid-binding protein II and the family of cytokeratins. The upregulation of the former protein is a well-known phenomenon, whereas the retinoid-induced regulation of epidermal keratin expression is more complex and only partially understood. We studied the effect of topical retinoids on the expression in healthy skin of cellular retinoic acid-binding protein II, tazarotene-induced genes 1 and 2, several epidermal keratins (K1, K2e, and K10), and two mucous keratins (K4 and K13) known to appear in epidermis under certain abnormal conditions. Reverse transcription-polymerase chain reaction experiments showed that the K4 expression was the one most overtly induced by 2 wk of open treatment with 0.05% of retinoic acid and tazarotene. Using real-time quantitative polymerase chain reaction (TaqMan) and normalization of the mRNA values to beta-actin, the increase in K4 was found to be 100-1000-fold. In comparison, the expression of K13 and cellular retinoic acid-binding protein II was increased 10-50-fold, the K1 and K10 mRNA levels remained unchanged, and the K2e level decreased by a factor of 100-1000. In parallel biopsies, immunohistochemistry showed no change in K1, K2e, or K10 staining, but a strong de novo appearance of K4 in the granular layer after retinoid treatment. In a separate study, occlusive application of 0.025% retinoic acid in four healthy subjects produced a maximal K4 mRNA signal after 48 h and strong K4 staining after 80 h. Finally, a dose-response study showed that the de novo appearance of K4 can be utilized as a sensitive test for retinoid bioactivity in epidermis in vivo.
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| 15. |
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| 16. |
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| 17. |
- Herzog, C, et al.
(författare)
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Dystroglycan in skin and cutaneous cells: beta-subunit is shed from the cell surface
- 2004
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Ingår i: Journal of Investigative Dermatology. - 1523-1747. ; 122:6, s. 1372-1380
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Tidskriftsartikel (refereegranskat)abstract
- In skin, hemidesmosomal protein complexes attach the epidermis to the dermis and are critical for stable connection of the basal epithelial cell cytoskeleton with the basement membrane (BM). In muscle, a similar supramolecular aggregate, the dystrophin glycoprotein complex links the inside of muscle cells with the BM. A component of the muscle complex, dystroglycan (DG), also occurs in epithelia. In this study, we characterized the expression and biochemical properties of authentic and recombinant DG in human skin and cutaneous cells in vitro. We show that DG is present at the epidermal BM zone, and it is produced by both keratinocytes and fibroblasts in vitro. The biosynthetic precursor is efficiently processed to the alpha- and beta-DG subunits; and, in addition, a distinct extracellular segment of the transmembranous beta-subunit is shed from the cell surface by metalloproteinases. Shedding of the beta-subunit releases the alpha-subunit from the DG complex on the cell surface into the extracellular space. The shedding is enhanced by IL-1beta and phorbol esters, and inhibited by metalloproteinase inhibitors. Deficiency of perlecan, a major ligand of alpha-DG, enhanced shedding suggesting that lack of a binding partner destabilizes the epithelial DG complex and makes it accessible to proteolytic processing.
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| 18. |
- Meding, Birgitta, et al.
(författare)
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Incidence of hand eczema-a population-based retrospective study.
- 2004
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Ingår i: Journal of Investigative Dermatology. - 0022-202X .- 1523-1747. ; 122:4, s. 873-7
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Tidskriftsartikel (refereegranskat)abstract
- When etiological relationship is of interest, the incidence rate is a preferred measure. The aim of the present retrospective study was to estimate the incidence rate of self-reported hand eczema in a sample from the general population and to study the relation of this to age, sex, and atopy. A questionnaire was mailed to 3000 individuals aged 20-65 y, randomly selected from the population register of Göteborg, Sweden. This gave a response rate of 73.9%. Questions were asked about ever having had hand eczema, time of onset of the disease, history of childhood eczema, and history of asthma/hay fever. The crude incidence rate of self-reported hand eczema was 5.5 cases per 1000 person-years (females 7.1 and males 4.0). There was no difference, however, in incidence rate between women and men above 30 y of age. In a Poisson regression analysis, female sex, childhood eczema, and asthma/hay fever were all significantly associated with hand eczema, but only at ages below 30 y. A moderate influence of recall bias and a probable tendency to underreport imply that the incidence rates presented are to be considered as minimum rates.
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| 19. |
- Mirastschijski, Ursula, et al.
(författare)
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Matrix metalloproteinase inhibitor BB-3103 unlike the serine proteinase inhibitor aprotinin abrogates epidermal healing of human skin wounds ex vivo.
- 2002
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Ingår i: Journal of Investigative Dermatology. - : Elsevier BV. - 1523-1747 .- 0022-202X. ; 118:1, s. 55-64
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Tidskriftsartikel (refereegranskat)abstract
- Several matrix metalloproteinases and serine proteinases are upregulated in migrating keratinocytes during cutaneous wound repair. Single cell culture studies indicate the necessity for matrix metalloproteinases but not for serine proteinases in keratinocyte locomotion. To account for epithelial-mesenchymal interactions, an ex vivo human skin wound model was used to investigate the contribution of matrix metalloproteinases and serine proteinases to wound healing by treatment with broad-spectrum inhibitors of matrix metalloproteinases (BB-3103) or serine proteinases (aprotinin). Human skin explants with circular 3 mm superficial defects were incubated in culture medium without (controls) or with the proteinase inhibitors for 7 d. BB-3103 abrogated epithelialization (p < 0.001), whereas aprotinin-treated wounds and controls were covered with new epithelium. Lack of epithelialization was unlikely due to cytotoxicity because the matrix metalloproteinase inhibitor did neither influence viability of cultured epidermal keratinocytes nor apoptosis in wounds. Involvement of specific matrix metalloproteinases in epithelialization was analyzed by gelatin zymography, western blotting, immunohistochemistry, and in situ hybridization. Wound healing was accompanied by active matrix metalloproteinase-1 and increased active matrix metalloproteinase-2 but irrespectively of active matrix metalloproteinase-9. BB-3103 blocked activation of matrix metalloproteinase-2 and matrix metalloproteinase-9 but not of matrix metalloproteinase-1. Active matrix metalloproteinase-2 localized solely to the dermis, whereas matrix metalloproteinase-9 was consistently found in new epithelium. Membrane-type 1 matrix metalloproteinase was undetectable in wound keratinocytes. BB-3103 and aprotinin reduced tumor necrosis factor-alpha in media but did not appreciably alter amounts of other soluble regulators of matrix metalloproteinases and epithelialization. Our findings demonstrate that keratinocyte migration is associated with active matrix metalloproteinase-2 but occurs independently of serine proteinases and active matrix metalloproteinase-9 in fibrin-deficient skin wound healing.
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| 20. |
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| 21. |
- Mørk, Cato, et al.
(författare)
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The Prostaglandin E1 Analog Misoprostol Reduces Symptoms and Microvascular Arteriovenous Shunting in Erythromelalgia : A Double-Blind, Crossover, Placebo-Compared Study
- 2004
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Ingår i: Journal of Investigative Dermatology. - : Nature Publishing Group. - 0022-202X .- 1523-1747. ; 122:3, s. 587-593
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Tidskriftsartikel (refereegranskat)abstract
- Based on previous experience with parenteral prostanoids, we studied the effect of misoprostol treatment, an orally administered prostaglandin E1 analog, in patients with erythromelalgia. Treatment with placebo was followed by treatment with misoprostol (0.4–0.8 mg per d), both for 6 wk. The patients (n=21) and a study nurse who administered the trial were blinded. The endpoints were change in pain and need for cooling and global assessment of the treatment. Following central body heat provocation, global skin perfusion, capillary morphology, and change in pain were also recorded before and after each treatment period. Results were compared with data from healthy control subjects (n=11) that did not undergo treatment. Clinical safety and tolerability evaluation included physical examinations, clinical laboratory tests, and monitoring of adverse events. All clinical outcome measures were significantly better after treatment with misoprostol (p<0.01) as compared with placebo treatment and after a 3-mo follow-up without treatment. The heat-induced increase in global perfusion after misoprostol treatment was similar to the control group and significantly lower when compared with baseline (p<0.01) and placebo treatment (p<0.05), respectively. This study demonstrates that misoprostol is clinically superior to placebo in patients with erythromelalgia. The results of the perfusion studies may imply that the mechanism of action of the beneficial effect of misoprostol is reduced microvascular arteriovenous shunting in affected skin.
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| 22. |
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| 23. |
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| 24. |
- Ringholm, Aneta, et al.
(författare)
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Pharmacological characterization of loss of function mutations of the human melanocortin 1 receptor that are associated with red hair
- 2004
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Ingår i: Journal of Investigative Dermatology. - 0022-202X .- 1523-1747. ; 123:5, s. 917-923
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Tidskriftsartikel (refereegranskat)abstract
- Variation in skin color is the major host risk factor for melanoma and other forms of skin cancer. Individuals with red hair show an increased ratio of phaeomelanin to eumelanin in both hair and skin. This ratio is regulated by the melanocortin (MC) 1 receptor. There are several common point mutations in the human MC1 receptor that are overrepresented in North European red-heads, and in individuals with pale skin. In order to determine the functional significance of these mutations, we expressed the Asp84Glu, Val92Met, Arg163Gln, and Asp294His variants of the human MC1 receptors in eukaryotic cells and determined their ability to bind alpha-melanocyte stimulating hormone (MSH) peptides and increase intracellular cAMP. The mutants Asp84Glu and Asp294His showed a much lower response to alpha-MSH in cAMP and a slightly impaired ability to bind alpha-MSH, and the Val92Met mutant bound alpha-MSH with 100-fold lower affinity as compared with the wild-type. The Arg163Gln variant, widely found in some Asian populations, reached normal level of cAMP response but had just slightly lower potency for alpha-MSH in binding and second messenger studies. The results provide important pharmacological characterization of common MC1 receptor variants in various world populations.
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| 25. |
- Stocklassa, B, et al.
(författare)
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Evaluation of a new X-ray fluorescent analysis technique for the creation of a Nordic hair database : Elemental distributions within the root and the virgin segment of hair fibers
- 2001
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Ingår i: JOURNAL OF COSMETIC SCIENCE. - New York : Society of Cosmetic Chemists. - 0037-9832 .- 1525-7886. ; 117:3, s. 312-
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Tidskriftsartikel (refereegranskat)abstract
- A new, non-destructive X-ray fluorescence technique for quantitative estimation of elemental content in biological tissues has been developed. Technical and instrumental characteristics of the ITRAX X-ray spectrometer have been evaluated in relation to the properties of biological samples, i.e., human hair fibers. Thus, attenuation variations of the fluorescent X-rays in the hair bulk mass were demonstrated by analysis of sulfur, calcium, and zinc in a virgin part near the root of one hair fiber with elliptical cross section. By rotation of the hair fiber and successive analyses made of the same part of the hair fiber, the results showed that concentrations of elements varied as functions of the diameter of the analyzed hair volume. Other sources of errors are also discussed. The ITRAX instrument allows for precise, fast, non-destructive, simultaneous, quantitative recording of the detected elements and trace elements down to levels of 1 ppm (mug/g). It was used fur assessment of normal values of physiologically important elements present in hair in a cohort of normal, healthy Swedish, Caucasian individuals. The database constructed from data retrieved from a conceivably homogenous ethnic set of individuals represents, to our knowledge, the first of its kind.
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