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Biomedical subjects

G Plewig

Publications and source records attributed to G Plewig.

At least 181 records · Page 10Linked to original sources
PubMed1991

Cytogenetic effects during extracorporeal photopheresis treatment of two patients with cutaneous T-cell lymphoma.

The effect of extracorporeal photopheresis (EP) on various cytogenetic parameters has been investigated. During EP the photoactivatable agent 8-methoxypsoralen (8-MOP) was administered orally. After 2 h a leukocyte-enriched blood fraction was collected by haemocentrifugation, irradiated with UVA extracorporeally, and reinfused to the patient. Two patients suffering from cutaneous T-cell lymphoma showed a marked clinical improvement in response to therapy. In order to investigate the cytogenetic effects and mutagenic risk of EP, the mitotic index (MI), the type and number of chromosomal aberrations and the rate of sister chromatid exchanges (SCE) were studied. Following EP treatment the patients' lymphocytes were cultured and stimulated with phytohaemagglutinin (PHA) for 48 or 72 h. The cultured lymphocytes showed a decreased MI after 48 h as an indicator of cytotoxic effects, but not after 72 h. In lymphocyte cultures not stimulated with PHA, the MI was decreased even after 72 h. The number of chromosomal aberrations and SCE were increased upon treatment, but only transiently, returning to basal levels between consecutive treatments. Our data provides no evidence for increased mutagenic risk as a consequence of effective EP treatment.

Administration, Oral↗
PubMed1991

UVA irradiation induces collagenase in human dermal fibroblasts in vitro and in vivo.

We report the effect of UVA irradiation on collagen metabolism of fibroblasts, including both synthesis of the collagen degrading enzyme collagenase and de novo synthesis of type I collagen as the major structural component of the dermis. For this purpose confluent fibroblast monolayers were irradiated under standardized conditions (5, 15, 35, 60 J/cm2 using UVASUN 3000, Mutzhas, Munich, FRG, and UV source Sellas sunlight type 2.001, Sellas, Gevelsberg, FRG). Subsequently, total RNA was isolated and subjected to dot blot and northern blot analysis using oligolabelled cDNA clones for human type I collagen, collagenase and beta-actin. Collagen type I and beta-actin mRNA levels remained unaltered following irradiation, suggesting that the synthetic pathway of collagen metabolism at the pretranslational level is not affected by short-term UVA irradiation. However, collagenase mRNA was found to be dose-dependently induced in fibroblasts after irradiation, thus probably contributing to the actinic damage to the dermis. These in vitro data were confirmed in vivo using in situ hybridization on frozen sections of biopsy material obtained from UVA irradiated patients.

Cell Division↗
PubMed1991

Photopatch testing: the 5-year experience of the German, Austrian, and Swiss Photopatch Test Group.

A cooperative photopatch test study was conducted by 45 dermatologic centers in Austria, Germany, and Switzerland. Results obtained from 1985 to 1990 are presented. A standard photopatch test tray of 32 substances was applied to the back of patients with suspected photosensivity. After applications for 24 hours, test sites were irradiated with 10 joules/cm2UVA. Unirradiated controls were included. Readings were performed immediately and 24, 48, and 72 hours after irradiation; responses were qualitatively graded on a 4-point scale. All data were stored and processed by a computer. With computer-assisted analysis of reaction patterns photoallergic reactions were identified and distinguished from phototoxic reactions. Data of 1129 patients were evaluated. Among a total of 2859 positive test reactions in 870 patients, 2041 in 778 patients were found to be photoinduced and 818 in 413 patients were contact reactions; 108 reactions in 83 patients were classified as photoallergic. Nonsteroidal anti-inflammatory drugs, disinfectants, sunscreens, phenothiazines, and fragrances caused most often photoallergic reactions. Many unspecific phototoxic reactions were induced by tiaprofenic acid, promethazine, carprofen, chlorpromazine, fenticolar, wood balsam of Peru, and perfumes. Despite the distinction between photoallergic and phototoxic responses, many test reactions lacked relevance for the patients' dermatoses.

Adolescent↗
PubMed1991

Disturbances of essential fatty acid- and prostaglandin E-mediated immunoregulation in atopy.

Impaired suppressor T lymphocyte maturation and function in atopic individuals are explained by an insufficient transmission of prostaglandin E (PGE) signals during thymic lymphocyte differentiation as well as an impaired ability of the atopic immune system to activate suppressor T-cells by PGE-mediated feed back mechanisms. We demonstrate that spontaneous in vitro immunoglobulin E synthesis of atopic peripheral blood mononuclear cells could be suppressed by the addition of 10(-6) M to 10(-5) M PGE1 or PGE2. Decreased plasma and breast milk levels of PGE-precursor fatty acids and reduced numbers of PGE2-receptors on atopic lymphocytes have been observed in atopic individuals. These insights might offer a novel approach for the prevention of atopic disease by substitution of the atopic pregnant and nursing woman and her newborn infant with long chain omega-6-fatty acids.

Adult↗
PubMed1991

Influence of UV irradiation on the composition of human stratum corneum lipids.

Irradiation with suberythemal doses of either UV-A or UV-B yielded an increase in the amount of stratum corneum lipids extracted from the lumbar skin area of 20 volunteers. These lipids were quantified after separation by high-performance thin-layer chromatography. Ten subfractions in the ceramide region were separated; two of them (fractions 7a and 7b) were only detectable after UV-A or UV-B irradiation. Improvement of barrier function after UV irradiation of human skin with suberythemal doses may be related to an increase in the stratum corneum ceramides.

Adult↗
PubMed1991

Are deficiencies of prostaglandin-E-mediated immunoregulation involved in increased IgE synthesis of atopic mononuclear cells in vitro?

We demonstrate that spontaneous in vitro immunoglobulin E synthesis of atopic peripheral blood mononuclear cells could be suppressed by the addition of 10(-6) M to 10(-5) M prostaglandin E1 (PGE1) or PGE2. Impaired suppressor T lymphocyte maturation and function in atopic individuals are explained by an insufficient transmission of prostaglandin E (PGE) signals during thymic lymphocyte differentiation as well as an impaired ability of the atopic immune system to activate suppressor T cells by PGE-mediated feed back mechanisms. Decreased levels of 6-desaturated PGE-precursor fatty acids in plasma, T lymphocytes, monocytes, adipose tissue and breast milk have been observed in atopic individuals. These insights might offer a novel approach to the prevention of atopic disease by substitution of the atopic pregnant and nursing woman and her newborn infant with long-chain omega-6-fatty acids.

Cells, Cultured↗
PubMed1991

Langerhans cell histiocytosis masquerading as lichen aureus.

We report a 13-year-old boy with localized Langerhans cell histiocytosis. The lesion was restricted to the skin of the mons pubis and clinically resembled lichen aureus. Histopathologic and electron microscopic examinations of a skin biopsy specimen of the lesion showed typical features of Langerhans cell histiocytosis. Extensive examination revealed no other organ involvement.

Adolescent↗
PubMed1991

Stratum corneum lipid function.

The stratum corneum contains a complex mixture of polar and nonpolar lipids in its intercellular spaces. These lipids, present in form of multiple lamellae, have been investigated for their role in providing the epidermal barrier to transcutaneous water loss, the selective barrier from the inside to the outside of the organism and partly the process of physiological desquamation. The composition of these lipids varies from species to species, with the body region and the degree of keratinocyte differentiation. The most undifferentiated layers of the epidermis contain typical membrane lipids, phospholipids, while more differentiated layers contain ceramides, cholesterol and free fatty acids. Essential fatty acids are essential for the maintenance of the lamellar structures and epidermal barrier function. Epidermal linoleic and arachidonic acids derive from exogenous sources. Only recently attempts have been made to elucidate the timing and regulation of epidermal fatty acid metabolism. Keratinocytes do not express a low molecular weight fatty acid binding protein like other cells active in lipid metabolism, but may employ alternative ways in fatty acid uptake and metabolism.

Basement Membrane↗
PubMed1991

Plasmapheresis in solar urticaria.

Three patients with solar urticaria were treated with plasmapheresis. By intradermal injection of in vitro irradiated serum the existence of a circulating photoallergen was demonstrated in cases 1 and 2 but not in case 3. Plasmapheresis induced complete remission of solar urticaria in case 1 and transient improvement in case 2. In case 3, however, no beneficial effect was observed. It is suggested that some patients with solar urticaria, probably those with a circulating photoallergen, may benefit from plasmapheresis.

Adult↗
PubMed1991

Persistent light reaction associated with photoallergic contact dermatitis to musk ambrette and allergic contact dermatitis to fragrance mix.

A 57-year-old man suffering from persistent light reaction with photocontact allergy to musk ambrette and contact allergy to fragrance mix was evaluated. A lowered minimal erythema dose to UV-B (MED-UV-B) was seen. Reactions to long-wave UV-A and visible radiation were normal. A skin biopsy from one MED-UV-B, taken 24 h after irradiation, showed acute spongiotic dermatitis.

Dermatitis, Contact↗
PubMed1991

[Immune regulatory importance of prostaglandins E in atopy].

The concept proposed for the pathogenesis and prevention of atopy [Hautarzt (1989) 40:685-692] is refined by further insights into the immunoregulatory role of E-prostaglandins. It is demonstrated that in vitro IgE synthesis of peripheral blood mononuclear cell cultures of patients with atopic dermatitis is suppressed by the addition of PGE1 or PGE2. The enhanced IgE production in atopy is explained by insufficient PGE-mediated down-regulation of interleukin-4-induced IgE synthesis.

Dermatitis, Atopic↗
PubMed1991

[Linear IgA dermatosis in childhood].

In a six-year-old girl with linear IgA dermatosis of childhood there were lesions with typical rosette like configuration, crusted erosions and isolated bullae on apparently normal skin. The histopathology revealed subepidermal blister and superficial perivascular lymphohistiocytic infiltrate with many neurophils and some eosinophils. Direct immunofluorescence examination showed linear deposits of IgA along the basal membrane zone. Circulating antibodies were absent. Therapy with dapsone in a dose of 25 mg/day was effective.

Autoimmune Diseases↗
PubMed1991

[Chronic actinic dermatitis. Concept and case examples].

Two women patients with chronic eczematous dermatitis, who also developed extremely severe, persistent photosensitivity during a course of 10 and over 40 years, are presented. Both patients had an atopic history with positive immediate skin reactions. Patch and photopatch tests revealed sensitization to several contact allergens, and in one case also a photocontact allergy. The action spectrum of the photosensitivity was confined to UV-B; it was possible to provoke eczematous skin reactions with doses smaller than 1 mJ/cm2 UV-B. Both patients were successfully treated with PUVA therapy. These case reports demonstrate the difficulty of nosological classification of chronic eczematous photosensitive dermatoses under the traditional terms persistent light reaction, photosensitive eczema, photosensitivity dermatitis, and actinic reticuloid. Chronic actinic dermatitis is defined clinically by chronic dermatitis on skin exposed to sun, histologically by spongiotic dermatitis, and photobiologically by experimental provocation of spongiotic dermatitis with UV-B and often also longer wavelengths in the absence of a photoallergen. Chronic actinic dermatitis should be used as a general term in addition to the more specific terms listed above.

Biopsy↗
PubMed1991

[Pomade crust of the scalp simulating cornu cutaneum].

A 63-year-old woman with a history of exaggerated use of topical skin care products of post-traumatic scarring alopecia presented with a monstrous cutaneous horn-like pomade crust of the scalp hidden beneath a wig. The crust consisted of corneocytes and bacterial debris. Pomade crusts have not been described previously in this localization. They are usually found in the inguinal or gluteal folds of infants, and occasionally in other body regions, e.g., on the face of adults.

Alopecia↗
PubMed1991

[Polymerase chain reaction with subsequent direct gene sequence analysis. A possibility for molecular analysis in dermatology].

Molecular analyses are of increasing importance in clinical research as well as for diagnostic evaluations. Gene alterations are involved in the pathogenesis of numerous diseases and are described in an increasing number of conditions. A method is presented which allows for rapid and detailed nucleotide sequence analysis of a segment of a gene. Buccal epithelial cells of a patient are obtained by means of a mouth wash with 10 ml water. DNA molecules are amplified in vitro using the polymerase chain reaction, followed by direct sequence analysis of the product. Using this technique, a sequence analysis of a gene segment is possible within 1-2 days. As an example, the analysis of a segment of the gene for uroporphyrinogen decarboxylase of patients with cutanea tarda is described.

Base Sequence↗