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Biomedical subjects

A Dobozy

Publications and source records attributed to A Dobozy.

At least 55 records · Page 3Linked to original sources

Kaposi's sarcoma-associated herpesvirus/human herpesvirus-8: a new virus in human pathology.

The discovery of a new human herpesvirus in Kaposi's sarcoma (KS) tissue of patients with AIDS has opened up new vistas in virology and oncology. This herpesvirus was first descriptively named KS-associated herpesvirus (KSHV), but was recently renamed human herpesvirus 8 (HHV8). KSHV/HHV8 DNA has been found in all forms of KS, suggesting that it might be involved in the pathogenesis of KS. In addition, KSHV/HHV8 can be detected in both malignant and benign lymphoproliferative disease. KSHV/HHV8 was also found in patients with angiosarcoma of the face and angiolymphoid hyperplasia with eosinophilia. Although only a limited portion of the virus has been sequenced, KSHV/HHV8 is equipped with genes that could confer oncogenic potential. The virus can now be cultured, providing the possibility for studies of viral replication and the mode of transmission. The recently developed serologic assays for antiviral antibodies suggest that infection with KSHV/HHV8 is not ubiquitous because KSHV/HHV8 seropositivity is limited to a small proportion of the population.

Acquired Immunodeficiency Syndrome↗

Pyodermatitis-pyostomatitis vegetans.

A 43-year-old woman developed annular and pustular cutaneous lesions preceded by tiny yellow pustules coating the surface of the oral mucosa. The clinical, histological and immunopathological evidence clearly showed that the patient had pyodermatitis-pyostomatitis vegetans. It is suggested that this disease is a distinct entity which should be differentiated from pemphigus vegetans.

Diagnosis, Differential↗

[Food allergy in patients with chronic urticaria].

Basic food allergens (bread, milk and egg) were investigated in patients with idiopathic chronic urticaria. In 29 of 43 patients, sensitivity could be shown against one or more antigens. The results suggest not only the anaphylactic IgE-mediated reaction in same patients, but also an antibody or cell-mediated mechanisms in the development of the disease. Besides the Prick test, therefore, testing of other circulating antibodies by means of the ELISA technique and the leukocyte migration test is recommended to establish the causative agents in patients with chronic urticaria.

Adolescent↗

[Porphyria cutanea tarda in a long-term hemodialysis patient].

A 61 year old man developed bullous skin lesions typical for porphyria cutanea tarda (PCT) after being on maintenance hemodialysis for 3 years. The porphyrin level in the urine, plasma, erythrocytes and stool supported the diagnosis of porphyria cutanea tarda, a very rare disease in patients with chronic renal failure on hemodialysis. Therapeutic possibilities are reviewed.

Humans↗

Identification of different circulating autoantibodies in patients with bullous pemphigoid and pemphigus vulgaris by means of immunoblotting.

Immunoblotting studies with salt-split human epidermis were performed on sera from 15 patients with pemphigus vulgaris and 20 patients with bullous pemphigoid by using peroxidase-labelled antihuman IgG and IgA. Eleven sera of pemphigus vulgaris antigen. Most of the sera gave additional specific bands at 210 and 80 kD, with lower intensity. The sera of 4 patients, 3 of them were in clinical remission, did not yield specific bands. Seventeen sera of the 20 bullous pemphigoid patients yielded a 220-230 kD protein band against the major bullous pemphigoid antigen and 4 of them gave another specific band at 160-180 kD. Five sera produced multiple bands (220, 130, 100 and 75 kD). IgA antibodies against the major bullous pemphigoid antigen were demonstrated in 2 cases with IgA deposits along their basement membrane, as revealed by direct immunofluorescence. The immunoblot patterns correlated only weakly with the clinical findings in bullous pemphigoid. There was a considerable diversity in both clinical findings and immunoblot patterns.

Aged↗

Detection of bullous pemphigoid antibodies by means of synthetic peptides as antigenic epitopes.

In an earlier study, the circulating autoantibodies in patients with bullous pemphigoid (BP) were demonstrated in higher frequencies by means of an immunoblot technique then via indirect immunofluorescence. In the present work with the help of Peptide Structure software, two matched antigenic epitopes were chosen and synthesized. The sera of 34 patients with BP were investigated in parallel by an immunoblot technique using a human epidermal extract, and by an ELISA technique with synthetic peptides. The sera of 16 healthy persons and 10 patients with other bullous diseases served as controls. Among the 34 patients with BP, 23 sera proved positive for at least one synthetic peptide. Positive reactions with the major BP antigen (230 kD) were found in 22 patients by immunoblot technique and in 16 patients by the ELISA technique with the synthetic peptide, whereas with the minor BP antigen (180 kD), positive reactions were found in 9 patients by the immunoblot technique and 18 patients by the ELISA technique using the synthetic antigenic epitope of the minor BP antigen. All control sera were negative for both antigens in ELISA investigations. In 3 patients with pemphigus vulgaris, characteristic bands against pemphigus vulgaris antigen were identified by means of the immunoblot technique, but all other cases were negative. It is suggested that the development of this technique may lead to an opportunity for the rapid and simple diagnosis of BP.

Adult↗

Human herpesvirus 8 in classic Kaposi sarcoma.

Recent studies suggest the role of a new human herpesvirus (HHV8) in the pathogenesis of different forms of Kaposi sarcoma (KS). In the present work we investigated the presence of HHV8 sequences in KS tumour tissues from patient with classic KS. Since clear evidences point to the role of immune suppression in the development of AIDS-associated KS or patients receiving immunosuppressive therapy, immunological investigations were also performed. We could show a highly consequent association of HHV8 sequences with classic KS in the large series of patients supporting our previous findings that this virus might be in some way involved in the pathogenesis of this tumour. In addition immunological examination of the patients revealed a mild decrease in the CD4 positive cell number, a significantly reduced CD4/CD8 ratio, a diminished PHA reactivity and leukocyte migration factor production of lymphocytes. The changes observed in the present study are similar, but much less pronounced than those may be observed in HIV infection.

Aged↗

Interleukin-8 induces HLA-DR expression on cultured human keratinocytes via specific receptors.

Recent studies suggest that interleukin (IL)-8 exerts a direct influence on several functions such as the chemotaxis or proliferation of human keratinocytes (HK). Since the effects of IL-8 in skin are mediated through specific receptors, we have studied the characteristics of the keratinocyte IL-8 receptor. We could identify specific binding sites for IL-8 in cultured HKs by flow cytometry. Pretreatment of the cells with tumor necrosis factor (TNF)-alpha or IL-1 alpha resulted in a significant increase in IL-8 binding. IL-8 selectively induced expression of HLA-DR antigen, but had no effect on the expression of other cell surface antigens (CD11a, CD18, CD36 and CD54).

Antigens, Surface↗

Alpha-melanocyte stimulating hormone induces collagenase/matrix metalloproteinase-1 in human dermal fibroblasts.

Recent reports have suggested that alpha-melanocyte stimulating hormone (alpha-MSH) plays an important role in untraviolet (UV) irradiation mediated skin changes including pigmentation, inflammation and connective tissue damage. alpha-MSH synthesis has been found to be induced in human keratinocytes following UV irradiation. In order to test the hypothesis whether UV induced alpha-MSH - via a paracrine loop - regulates the synthesis and the activity of collagenase/MMP-1, we studied the effects of alpha-MSH on the expression of MMP-1 and its tissue inhibitor of matrix metalloproteinases (TIMP-1). Confluent human dermal fibroblast cultures from foreskin biopsies of healthy human donors were treated with 10(-5)M, 10(-8)M and 10(-11)M alpha-MSH for 30 min. As determined by Northern blot analysis 10(-5)M and 10(-8)M alpha-MSH dose- and time-dependently induced steady state levels of MMP-1 mRNA up to 9-fold compared to untreated controls. TIMP-1 mRNA steady state levels were also slightly induced, however, the increased MMP-1/TIMP-1 ratio when normalized to beta-actin reflected an unbalanced synthesis. MMP-1 protein expression was studied with an immunofluorescence technique using a monoclonal antibody against MMP-1. After alpha-MSH treatment an increased number of fibroblasts revealed an intense perinuclear staining pattern compared to the less intense staining of control fibroblasts. The overall collagenolytic activity of supernatants from alpha-MSH treated fibroblasts was increased by 35%. Our data support the view that UV induced alpha-MSH - by the stimulation of collagenase/MMP-1 - may contribute to the loss of interstitial collagen related to cutaneous photoaging.

Cell Extracts↗