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R Dummer

Publications and source records attributed to R Dummer.

At least 163 records · Page 9Linked to original sources
PubMed1995

Interleukin 2-induced increase of vascular permeability without decrease of the intravascular albumin pool.

Interleukin 2 (IL-2) exhibits anti-tumour activity. High-dose IL-2 regimens are limited by side-effects such as pulmonary oedema and a systemic vascular leak. The mechanisms by which IL-2 mediates transvascular fluid and protein losses in humans are largely unknown. We have, therefore, measured the transcapillary escape rate (TER) of albumin as a reflection of the vascular permeability by injecting [125I]albumin (5 microCi i.v.). In ten melanoma patients pretreated with interferon alpha (IFN-alpha) TER of albumin was measured before and after IL-2 injections (1.5 x 10(6) Cetus-U. s.c. daily for 4 days). The TER of albumin increased from 9.4 +/- 2.7% h-1 before to 14.9 +/- 3.3% h-1 (P < 0.001) after IL-2 injections and the absolute outflux of albumin (Jalb) from 159 +/- 28 mg kg-1 h-1 to 261 +/- 44 mg kg-1 h-1 (P < 0.001), whereas the intravascular albumin pool remained stable (136 +/- 19 g vs 136 +/- 18 g). IL-2 and IL-6 were not detectable in the plasma prior to IL-2 injections and increased to 549 +/- 315 U ml-1 (P < 0.001) and 7 +/- 6 pg ml-1 (P < 0.01), respectively, after IL-2 administration. In conclusion, IL-2 increases the vascular permeability in humans, without affecting the intravascular albumin pool. This suggests that mechanisms such as the lymphatic return can compensate for the severe transendothelial fluid/albumin losses.

Adult↗
PubMed1995

Necrotizing herpes zoster mimicking relapse of vasculitis in angioimmunoblastic lymphadenopathy with dysproteinaemia.

An 81-year-old man presented with a generalized maculopapular rash, lymphadenopathy, conjunctivitis and arthritis. Vasculitis was confirmed by skin biopsy and by direct immunofluorescence, which showed perivascular C3 and granular IgM accumulation. Histology of an inguinal lymph node was diagnostic for angioimmunoblastic lymphadenopathy with dysproteinaemia (AILD), and this was confirmed by the finding of hypergammaglobulinaemia and elevated IgE levels. Immunohistology on a lymph node biopsy showed a T-helper cell (CD4) infiltrate expressing the interleukin (IL)-2 receptor alpha and beta chains. While receiving prednisone 100 mg/day, the patient developed new lesions, mimicking a relapse of vasculitis, which were subsequently shown to be necrotizing herpes zoster. Serum IL-2 and IL-6 levels were elevated. To our knowledge, this is the first report of simultaneous elevation of IL-2 and IL-6 in AILD: IL-2 may be involved in proliferation of the malignant cell clone, and IL-6 in the pathogenesis of both the vasculitis (via endothelial cell activation) and the hypergammaglobulinaemia.

Aged↗
PubMed1995

Staging of metastatic melanoma by whole-body positron emission tomography using 2-fluorine-18-fluoro-2-deoxy-D-glucose.

Metastatic melanoma was staged in 15 patients using whole-body positron emission tomography (PET) and the radiopharmaceutical 2-fluorine-18-fluoro-2-deoxy-D-glucose (FDG). PET correctly demonstrated 30 metastases in lung, brain, pancreas, nasal cavity, skin and subcutaneous tissue, and lymph nodes. It detected 97% of all metastases exceeding its spatial resolution (> 5 mm). Two cutaneous metastases (approximately 3 mm) did not show increased FDG uptake; the overall detection sensitivity was 91%. Two false-positive lesions in one patient were due to severe wound infection. PET correctly excluded malignancy in four cases where suspicious lesions were found with conventional cross-sectional imaging modalities but later ruled out by fine-needle biopsy. PET therefore proved to be an excellent method for staging of metastatic melanoma. Due to its high sensitivity for malignant lesions and the possibility of covering the whole body in one examination, it can replace staging techniques employing multiple imaging modalities: chest X-ray, ultrasonography and computed tomography. Furthermore, it provides information on the malignant potential of the detected lesion.

Adult↗
PubMed1995

Expression of bcl-2 protein and Ki-67 nuclear proliferation antigen in benign and malignant cutaneous T-cell infiltrates.

The bcl-2 protein prolongs cell life by inhibiting apoptosis. Its expression has been studied in a variety of normal tissues and lymphomas but there is minimal information available concerning bcl-2 expression by benign and malignant cutaneous T-cells. Therefore, we investigated bcl-2 expression in a wide variety of cutaneous T-cell infiltrates using one- and two-color immunohistologic techniques. bcl-2 was expressed by the majority of lesional CD3+ T-cells in most cases. This included 22/26 cases of mycosis fungoides (MF), 3/3 cases of non-MF cutaneous T-cell lymphoma, 5/5 cases of lymphomatoid papulosis, 4/4 cases of T-cell rich cutaneous lymphoid hyperplasia, 2/3 cases of bullous pemphigoid, 2/2 cases of discoid lupus erythematosus and 1/1 case of lichen planus. Titration experiments and comparative studies of tonsil section positive controls revealed that, relative to mantle zone B-cells, there was over- expression of bcl-2 by a variable subset of T-cells in most cases. Assessment of multiple biopsies in a subset of MF cases showed stable expression of bcl-2 over intervals of up to two years. In contrast to the widespread expression of bcl-2 in both early and advanced MF skin lesions, abundant expression of the nuclear proliferation antigen, Ki-67, was skewed toward advanced MF skin lesions. Ten percent or more Ki-67+ cells were present in 5% of patients with patches/thin plaques, 38% with moderate plaques, 64% with thick plaques and 100% with tumor nodules.(ABSTRACT TRUNCATED AT 250 WORDS)

Humans↗
PubMed1995

Anti-melanoma monoclonal antibody 225.28S immunoscintigraphy in metastatic melanoma.

BACKGROUND: Accurate staging and early detection of metastases are crucial to melanoma management. It would thus be of great value to have a widely available, cost-effective method that allows to examine the whole body and is more specific than current imaging modalities. OBJECTIVE: The purpose of the study was to assess the value of immunoscintigraphy with 99mTc-radiolabeled F(ab')2 fragments of the 225.28S monoclonal antibody in the staging of melanoma. METHODS: 29 patients with known or suspected metastases were enrolled in the study and examined by monoclonal antibody fragment scintigraphy. The results were compared to physical examination, other imaging modalities and, where available, histology. RESULTS: Antibody scintigraphy detected 9/34 metastases. There were 2 false-positive lesions. Diagnostic accuracy was 41%, sensitivity 26% and specificity 83%. CONCLUSION: 99mTc-radiolabeled F(ab')2 monoclonal antibody-fragment scintigraphy cannot be recommended for staging of melanoma patients. The search for more sensitive radiopharmaceuticals for scintigraphy should thus be encouraged.

Adult↗
PubMed1995

Lymphomatoid papulosis--treatment with recombinant interferon alfa-2a and etretinate.

Lymphomatoid papulosis is a rare cutaneous lymphoproliferative disorder with nodular, papulonecrotic or plaque-like lesions. Although it is clinically benign, the histology shows large, atypical lymphoid cells that display antigenic markers of activated T-helper lymphocytes and express CD30. There is a close relationship to Hodgkin's disease and to Ki-1-positive anaplastic large-cell lymphoma of the skin. For therapy, various modalities such as PUVA, steroids and acyclovir have been used. We report on a patient with a 10-year history of disease. Treatment with interferon alfa-2a, 3 MU 3 times/week for 4 weeks, and etretinate, 50 mg/day for 5 months, was initially successful, but lesions further relapsed 5 months after cessation of the therapy.

Adult↗
PubMed1995

Pathology of cutaneous T-cell lymphoma.

Clinical features as well as histomorphology and cytomorphology are the golden standard for the differentiation of the various nosologic entities of cutaneous lymphomas, consisting of pre-lymphomas and pseudolymphomas, abortive lymphoma, latent lymphoma, definite low grade malignant lymphoma, and high grade malignant lymphoma. Histomorphologic and cytomorphologic criteria allow additional subtyping of lymphoproliferative T-cell infiltrates of the skin.

Humans↗
PubMed1994

Influence of various cytokines on the interleukin-2-dependent lysis of melanoma cells in vitro.

To obtain information about useful combinations of various cytokines in melanoma therapy, we studied the influence of interleukin-2 (IL-2) in combination with interferon-alpha (IFN-alpha), IFN-gamma and tumour necrosis factor-alpha (TNF-alpha) on the lytic activity of IL-2-stimulated cells in vitro. Peripheral mononuclear cells (PMC) were incubated for 4 days with various combinations of cytokines and used as effector cells. Two different melanoma cell lines (M19 and M26) were used as target cells. The lytic activity of stimulated PMC was determined using a modified hexosaminidase assay. IL-2 was mainly responsible for the lytic activity of the effector cells in a dose-dependent manner. IFN-alpha, IFN-gamma and TNF-alpha did not enhance lytic activity with an optimal IL-2 dose (50 IU/ml IL-2). Using a suboptimal IL-2 dose (5 IU/ml), they increased cytotoxicity. The specific lysis of M19 cells was significantly increased by pretreatment of the cells with 5 IU/ml IFN-alpha together with 50 IU/ml TNF-alpha (t-test, P < or = 0.001), while the specific lysis of M26 cells was increased by pretreatment with 5 IU/ml IFN-gamma. We conclude that the lysis of melanoma cells by cytotoxic cells in vitro can be enhanced by various cytokines. The optimal cytokine combination differed for the two melanoma cell lines tested.

Cytokines↗
PubMed1994

Various cytokines modulate ICAM-1 shedding on melanoma- and CTCL-derived cell lines: inverse regulation of ICAM-1 shedding in a Sézary cell line by interferon-gamma.

BACKGROUND: Since soluble intercellular adhesion molecules 1 (sICAM-1) retain their ability to bind to their ligand, they can interfere in cell-mediated immunosurveillance. OBJECTIVE: We studied the impact of various cytokines on ICAM-1 release of several tumor cell lines. METHODS: Two melanoma cell lines (M19, M26), 1 B lymphoblastoid cell line (Daudi), 1 erythroleukemia cell line (K562), 1 Sézary-cell-derived cell line (SeAx), 1 cell line derived from a mycosis fungoides lesion (MyLa) and normal peripheral blood mononuclear cells (PBMC) were grown in the presence of interferon gamma (IFN-gamma), IFN-alpha, interleukin-2 (IL-2), IL-6 and tumor necrosis factor alpha (TNF-alpha) in various concentrations. ICAM-1 release into the supernatant was measured after 24 and 48 h using an enzyme-linked immunosorbent assay (ELISA). RESULTS: PBMC and the B lymphoblastoid cell line did not shed detectable amounts of sICAM-1. In all other cell lines, ICAM-1 shedding was found with and without cytokine stimulation. In all cell cell lines except the CTCL-derived one, ICAM-1 shedding was marginally affected by IFN-alpha, IL-2 and IL-6. TNF-alpha and IFN-gamma enhanced the shedding in a time- and dose-dependent manner. In the SeAx line, IL-2 and IFN-gamma inhibited ICAM-1 release. By contrast, TNF-alpha and IL-6 enhanced it. The CTCL-derived MyLa responded to IFN-alpha with a dose-dependent increase in ICAM-1 shedding. All other cytokines had marginal influence. CONCLUSION: Cytokine-modulated ICAM-1 shedding shows quantitative and qualitative differences in the investigated cell lines. This might have implications for the pathophysiology of cutaneous malignancies and their susceptibility to immunotherapies.

Antigens, CD↗
PubMed1994

Classification of cutaneous lymphomas.

Despite the many distinct features of cutaneous lymphomas, they are best classified according to the Kiel classification and the Working Formulation for clinical usage. T-cell lymphomas predominate (65%); however, there are a significant number of primary B-cell lymphomas of the skin (25%). Moreover, there are a variety of unusual and rare manifestations and nosologic entities of cutaneous lymphomas that cannot be seen in the lymph node owing to the peculiarities of the skin as a distinct homing organ and vice versa (10%). It is important to note that some cutaneous lymphomas have a better prognosis when occurring primarily in the skin than their corresponding entity in the lymph node.

Humans↗
PubMed1994

Molecular biology techniques for the diagnosis of cutaneous T-cell lymphoma.

The molecular biologic analysis of TCR gene rearrangements by Southern blot analysis and various PCR-based assays has contributed significantly to the understanding of CTCL. It is now known that CTCL is a monoclonal T-cell disorder like other T-cell neoplasms and that the same tumor clone is generally present in all sites of tissue involvement. Relative to histopathologic examination, the enhanced sensitivity of molecular biologic assays has allowed the diagnosis of CTCL at an early stage in many cases. In fact, molecular biologic analysis of TCR gene rearrangements suggests that CTCL may contain a dominant monoclonal tumor cell population from the time of its earliest clinically recognizable lesions, such as the cutaneous patches once termed large plaque parapsoriasis and now generally regarded as early CTCL. Furthermore, available data indicate that, at least in some cases, tumor cells are distributed widely among cutaneous and extracutaneous tissues at a time long before this involvement can be appreciated morphologically. It is apparent that, in addition to their value in the early diagnosis and staging of cutaneous lymphomas, these molecular biologic assays are valuable in monitoring the response to therapy, detecting early relapse, and improving understanding of the compartmentalization and trafficking of tumor cells. In order to reap the full clinical benefit from this new information, however, it is important to perform prospective long-term studies designed to determine the clinical significance of molecular biologic data. In addition, the complexity of cutaneous lymphoproliferative disorders dictates that molecular biologic clonality data should never be interpreted in a vacuum. In skin disease, dominant clonality does not always equate with clinical malignancy. The proper diagnosis of CTCL and other cutaneous lymphoproliferative diseases requires the thoughtful integration of molecular biologic data with the clinicopathologic and immunophenotypic findings.

Blotting, Southern↗
PubMed1994

Cytokines as regulatory proteins in lymphoproliferative skin infiltrates.

Cytokines are a heterogeneous group of modulatory molecules. They include multifunctional nonspecific mediators, chemokines, lymphocyte-stimulating factors, colony-stimulating factors, and interferons. Using contact dermatitis as an example of benign cutaneous lymphoproliferation and MF as an example of malignant cutaneous lymphoproliferation, we point out the pathophysiologic implications of these key molecules of the cutaneous cytokine network. We try to attribute morphologic features of benign and malignant cutaneous lymphoproliferation to effects mediated by cytokines in the context of the epidermal cytokine network. The knowledge of these interactions will allow a pathophysiologically oriented understanding of skin diseases, which will have consequences on therapeutic aspects of benign and malignant lymphoproliferation.

Colony-Stimulating Factors↗
PubMed1994

Semimalignant ("pseudolymphomatous") cutaneous B-cell lymphomas.

Almost 50% of cutaneous B-cell lymphoproliferative infiltrates are derived from follicular center cells. Among these, about 25% show a rapidly progressive course, whereas about 75% account for flattening of the survival curve after about 7 years. This group is referred to as semimalignant ("pseudolymphomatous") cutaneous B-cell lymphoma (SM-CBCL). Clinical, histologic, and phenotypical criteria for their differentiation from B-cell pseudolymphoma and from CBCL have been investigated in 60 patients (11 CBCL, 30 SM-CBCL, 19 PSL). Semimalignant CBCL are different from malignant CBCL because they do not tend to disseminate to extracutaneous sites or to transform into high-grade malignant blast-type lymphomas; follicular center cell formation with CD21 positive dendritic reticulum cells is usually present; and normal survival time is not affected. On the other hand, SM-CBCL differ from PSL in that complete cure of the usually multiple and disseminated skin manifestations is not possible and that follicular center formation and the network of CD21-positive cells in conjunction with a kappa or lambda light chain restriction of cellular surface immunoglobulins is seen. If these and other criteria are taken together, differentiation of these various nosologic entities demanding different therapeutic approaches can be achieved with significant reliability.

Adolescent↗