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Biomedical subjects

A Dobozy

Publications and source records attributed to A Dobozy.

At least 91 records · Page 5Linked to original sources
PubMed1992

Erythrocyte uroporphyrinogen decarboxylase activity in 80 unrelated patients with porphyria cutanea tarda.

To estimate the prevalence of the subgroups of porphyria cutanea tarda (PCT), erythrocyte uroporphyrinogen decarboxylase (UD) activity was measured in 80 unrelated patients with PCT, and in 45 of their relatives by using pentacarboxyl-porphyrinogen III as substrate. The subgroups were differentiated by analysis of the urinary porphyrins of the patients and 119 of their relatives. Of the patients, 77.5% were found to be suffering from the sporadic form of PCT (type I PCT), and 22.5% from the familial form (type II PCT). Every patient with PCT had previously been affected by alcohol, oestrogen or some other liver-damaging factor. The relative frequency of familial PCT was higher in females (nine of 15) than in males (nine of 65), which suggests that inheritance of the gene for type II PCT may predispose to oestrogen-precipitated PCT. The onset of type II PCT occurred at a lower age than that of type I (42.6 vs. 47.0 years). The findings suggest an increased risk of precipitating factors in carriers of an inherited UD deficiency.

Adult↗
PubMed1992

Expression of beta-2 integrin molecules on human keratinocytes in cytokine-mediated skin diseases.

Integrins are cell surface molecules of importance in a wide variety of cellular functions, including morphogenesis, cell migration and cell matrix interactions. The beta-2 (B2) integrin (leukocyte integrin, CD11/CD18) subfamily comprising three members, each consisting of a shared beta subunit (CD18) non-covalently associated with unique alpha subunits (CD11a, CD11b, CD11c). In the present study, we have analysed the expression pattern of B2 integrins on the surface of human keratinocytes (HKs) in biopsies obtained from healthy volunteers, from positive tuberculin skin tests and from patients with acute urticaria (AU), lichen planus (LP), psoriasis vulgaris (PV), mycosis fungoides (MF) or purpura pigmentosa chronica (PPC). In biopsies obtained from positive tuberculin tests and from the clinically involved skin of patients with LP, PV, MF or PPC, a multifocally occurring, suprabasal peroxidase-positive reaction was observed on the membranes of the HKs when the monoclonal antibodies (MABs) Dako CD11a, Dako-p150, 95 or Dako CD18 were used. In contrast, no specific staining of the HKs was observed with the same MABs in biopsies from healthy volunteers, from patients with AU and in the uninvolved skin specimens obtained from the other patients. The HKs from PV, LP, MF, PPC and AU patients and those from the healthy subjects failed to give a positive reaction when the MAB against CD11b (OKM1) was used. Our present findings provide further evidence that HKs may be actively involved in cell adhesion processes.

Antigens, CD↗
PubMed1991

Expression of complement receptor CR2 (CD21) on human subcorneal keratinocytes in normal and diseased skin.

Human keratinocytes are able to synthesize and express cell surface moieties characteristic of effector and/or accessory cells of the immune system (CD16, CD36, HLA-DR, intercellular adhesion molecule-1). In the present study, skin biopsies from healthy volunteers, from patients with psoriasis vulgaris (PV), mycosis fungoides (MF), purpura pigmentosa chronica (PPC), acute urticaria (AU) and from positive tuberculin skin tests were investigated with regard to the reactivity with the monoclonal antibodies to complement receptors CR1 CR2 and CR3 by means of a multistep immunoperoxidase method. In the clinically involved skin of all patients with PV, MF or PPC, and in biopsies obtained from positive tuberculin tests, specific epidermal intercellular staining with OKB7 and Leu anti-CR2 was seen on subcorneal keratinocytes. This finding suggests a differentiation-linked expression of CR2 on human keratinocytes in cytokine-mediated skin diseases whereas CR1 and CR3 are apparently not expressed.

Antigens, CD↗
PubMed1991

The occurrence of antinuclear, anti-SSA/Ro and anti-SSB/La antibodies in patients with polymorphous light eruption.

Serological features were investigated in 22 patients with polymorphous light eruption. The diagnosis was made from the history and clinical patterns and confirmed by phototesting and histological examinations. In 4 patients with polymorphous light eruption, anti-RNP antibodies were detected in the serum despite the fact that the antinuclear antibody tests were negative in all cases. The serum levels of anti-SSA/Ro antibodies in the patients were mildly but significantly elevated (p less than 0.001) as compared with healthy controls. No difference was found between the patients and controls regarding the serum concentrations of anti-SSB/La antibodies. The conclusion is drawn that it is necessary to examine patients with polymorphous light eruption with regard to a 'late autoimmune course' and it is worthwhile to study the relationship between the photosensitivity and the occurrence of anti-SSA/Ro antibodies.

Adult↗
PubMed1990

The mouse erythrocyte binding receptor is expressed on human keratinocytes.

Immunocytes and different types of epidermal cells share cell surface antigen characteristics e.g. keratinocytes react specifically with the Leu 11 (CD16) monoclonal antibody and they express MHC class II and OKM5 (CD36) antigens after gamma-interferon stimulation. The present study provides evidence that a subpopulation of human keratinocytes most probably at a certain stage of differentiation, possesses the mouse erythrocyte binding receptor the marker of a human B lymphocyte subset. This finding is a further evidence for the relationship between the epidermis and the immune system.

Animals↗
PubMed1989

[The irritant effect of dithranol using capillary resistance measurement].

The effect of topically applied dithranol on the capillary resistance (CR) was studied both in healthy volunteers and in clinically unaffected skin of psoriatic patients. The CR of the psoriatic patients was significantly lower than that of the healthy persons. O.10% and 0.25% dithranol ointment induced a significant decrease of CR in the skin of both groups. This decrease was prevented or at least reduced, if the patients had previously been treated with either the antihistamine clemastine or the cyclooxygenase-inhibitor indomethacin. The effect of dithranol on the CR was also moderated, if 5% coal tar had been added to the dithranol preparation.

Adult↗
PubMed1989

Pharmacological studies on dithranol-induced irritative dermatitis in mice.

The effects of different pharmacological substances on dithranol-induced irritative dermatitis were studied in mice. Pretreatment of the animals with a specific platelet activating factor (PAF) antagonist, BN 52021, significantly reduced the ear swelling in a dose-dependent manner. The cyclooxygenase inhibitor indomethacin, the antihistamine clemastine, and the anti-oxidant superoxide dismutase also proved to be effective in the reduction of the dermatitis. The results provide evidence of the coinvolvement of PAF, prostaglandins, histamine, and reactive oxygen radicals in dithranol-induced irritative dermatitis in mice.

Animals↗
PubMed1989

Cryopreserved 3T3 fibroblasts retain their capacity to enhance the growth of human keratinocyte cultures.

Cultured epithelial grafting of full-thickness skin defects is a new promising possibility for the successful treatment of patients with large burns. The major obstacle to this method, however, is a 3-4-week interval between burn and grafting, which is necessary for the growth of sufficient quantities of cultured epithelium. Generally, growth-arrested murine 3T3 fibroblasts have been used with success as feeder layers to shorten the cultivation time of keratinocytes. In the present work we have initiated studies to determine whether or not cryopreserved growth-arrested 3T3 fibroblasts retain their capacity to enhance the growth of human keratinocytes in vitro. The results of this study show that the [3H]thymidine incorporation in cultures containing mitomycin C treated 3T3 feeder cells was significantly greater than in cultures without feeder cells. Furthermore, in keratinocyte cultures containing freshly separated or cryopreserved 3T3 fibroblasts, a similar rate of [3H]thymidine incorporation was observed and the activity of incorporation has never differed significantly during the 11 days of culturing, meaning that cryopreserved, growth-arrested 3T3 fibroblasts retain their ability to enhance the growth of human keratinocytes. This observation renders the continuous maintenance of 3T3 cells unnecessary in laboratories which want to culture keratinocytes without delay.

Animals↗
PubMed1989

Enhancing effect of whole-body ultraviolet light irradiation on Candida albicans activity of human polymorphonuclear leukocytes.

In an irradiation dose-dependent manner, the whole-body ultraviolet irradiation of healthy volunteers enhances the Candida albicans killing activity of the circulating polymorphonuclear granulocytes. This enhancing effect can be inhibited by oral indomethacine treatment. The sera of the irradiated subjects enhances the killing activity of the granulocytes of untreated individuals. This transfer can be blocked through the administration to the system of ginkgolide B, a competitive antagonist of the platelet activating factor.

Candida albicans↗
PubMed1989

[Coexistence of porphyria cutanea tarda and lupus erythematosus].

We report on the appearance of porphyria cutanea tarda in a patient with systemic LE and in two patients with discoid LE. A review is given on the corresponding literature. It is suggested that both lupus erythematosus and porphyria cutanea tarda have multifactorial inheritance. The cause of coexistence can be common genes responsible for the genetic determination which also predispose to the occurrence of both diseases. The question of etiology still remains obscure. This coexistence raises, however, a more practical question as regards the therapeutic modalities for the two diseases.

Adult↗