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Biomedical subjects

G Brittinger

Publications and source records attributed to G Brittinger.

At least 55 records · Page 3Linked to original sources
PubMed1994

Philadelphia chromosome-positive chronic myelogenous leukemia: functional defects in circulating mature neutrophils of untreated and interferon-alpha-treated patients.

This study focuses on possible functional defects of circulating mature neutrophils in chronic phase chronic myelogenous leukemia (CML) and their modulation by interferon-alpha (IFN-alpha). Polymorphonuclear cells (PMN) of seven untreated and nine IFN-alpha-treated patients were evaluated for the following parameters by the following methods: generation of oxygen species, by luminol-dependent chemiluminescence; leukotriene B4 (LTB4) generation, by high-performance liquid chromatography (HPLC); expression of LTB4 and formylmethionyl-leucyl phenylalanine (FMLP) receptor sites, by 3H-binding assay; and GTPase activity, by 32P-gamma-GTP. Compared to normal controls, reduced values were obtained in treated and untreated CML for most parameters studied. Therapy with IFN-alpha resulted in significantly diminished values for oxygen species (NaF stimulation) and LTB4 (FMLP stimulation) generation, as well as FMLP receptor expression as compared to untreated CML. We conclude that alterations at the level of oxygen species production, mediator generation, receptor expression, and transmembrane signaling are involved in functional defects of circulating mature neutrophils from CML patients. IFN-alpha seems to enhance some of these functional defects, but the clinical relevance of these findings has be elucidated.

Adult↗
PubMed1993

Randomized, double-blind, placebo-controlled, phase III study of recombinant human granulocyte-macrophage colony-stimulating factor as adjunct to induction treatment of high-grade malignant non-Hodgkin's lymphomas.

We evaluated recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF; Sandoz Pharma [Basel, Switzerland]/Schering-Plough [Kenilworth, NJ]) as an adjunct to a modified (mainly cyclophosphamide and doxorubicin increased 1.5-fold) COP-BLAM regimen in the primary treatment of high-grade malignant non-Hodgkin's lymphomas (NHL). Patients (n = 182; stage II-IV; age, 15 to 73 years) were randomized to rhGM-CSF (400 micrograms) or placebo for 7 days subcutaneously after chemotherapy. Efficacy was analyzed for patients receiving at least 70% of study medication (n = 125). The frequency of clinically relevant infection was reduced by rhGM-CSF (28 v 69 infections, 16 v 30 patients, P = .02) with a cumulative probability of remaining infection free in 70% versus 48% (P = .05 log rank test at 190 days). Periods of neutropenia (P = .01 in 5 of 6 courses), days with fever (2.1 v 4.0, P = .04) and days of hospitalization for infection (3.5 v 8.0 days, P = .01) were significantly reduced. Complete response (CR) rates, assessed by prognostic risk, were 15 of 19 (79%) in treated versus 20 of 21 (95%) in controls in the low-risk group (P = .12). In the high-risk group, 31 of 45 (69%) treated patients achieved CR versus 25 of 52 (48%) of controls (P = .04). No difference in survival has been seen after 1 year. Only injection site reactions (45% treated v 7% controls) and rash (26% v 2%) occurred more frequently in treated patients (n = 176). These data show that rhGM-CSF is well tolerated in most patients with NHL, significantly reduces infection, and improves response.

Adolescent↗
PubMed1993

Detection of distinct sets of newly synthesized polypeptides in supernatants of TCR-triggered T cell clones. Implication for the search for new lymphokines.

Using metabolic radiolabelling of proteins, which are newly synthesized during TCR-triggered T cell activation we were able to visualize distinct patterns of secreted polypeptides (with molecular weights ranging from 6 to 44 kDa) in supernatants of different T helper-1, T helper-2 and cytotoxic T cell clones. Most of these detected proteins are secreted in response to TCR-crosslinking (or to combined action of PMA and A231287), in an extracellular Ca(2+)-dependent manner and their appearance in supernatants was completely blocked by the addition of RNA synthesis or protein synthesis inhibitors or EGTA. Cyclosporin A (CsA) blocks secretion of several detected polypeptides, but does not affect TCR-triggered synthesis and secretion of others reflecting the existence of TCR-triggered, CsA-insensitive protein synthesis and secretion pathway. The insensitivity of secretion of several easily detectable polypeptides to inhibition by CsA offers a promising approach to further define the CsA-resistant and calcineurin-independent molecular pathways of TCR-triggered T cell activation. Several lymphokines (e.g., interferon-gamma, tumor necrosis factor, interleukin-4 and interleukin-10) are identified among the visualized set of secreted polypeptides. Since other, yet unidentified, secreted polypeptides in the same set of secreted proteins share important properties with known lymphokines it seems promising to use described approach in search for new lymphokines.

Animals↗
PubMed1993

Regulation of the T cell receptor-alpha mRNA expression in the human lymphoblastic T cell line CEM.

We analyzed the transcriptional events involved in the T cell receptor (TcR)-alpha mRNA expression in a human lymphoblastic T-cell line CEM. CD3-negative and CD3-positive CEM subclones that either lack mature TcR-alpha mRNA or express TcR-alpha mRNA were used. Exposure of the TcR-alpha mRNA negative subclones to phorbol 12-myristate 13-acetate (PMA) was followed by 2- to 3-fold increase of transcription, indicating that PMA acts on a transcriptional level. No increase of transcription was observed after blocking protein synthesis with cycloheximide (CHX) or after sequential stimulation with CHX followed by PMA. On the posttranscriptional level, CHX as well as PMA induced a progressive stabilization of TcR-alpha mRNA in the nuclear compartment, which was independent of ongoing transcription. The half-life of the TcR-alpha mRNA upon stimulation was about 6 hours. The accumulation of mature TcR-alpha mRNA seemed to be controlled by nuclear events on a transcriptional as well as posttranscriptional level. The data imply that alterations of TcR-alpha gene transcription are dependent on protein synthesis. DNA-binding proteins enhance transcription and labile nuclear proteins target TcR-alpha mRNA for rapid turnover.

Cell Line↗
PubMed1992

Treatment of angioimmunoblastic lymphadenopathy (AILD)-type T-cell lymphoma using prednisone with or without the COPBLAM/IMVP-16 regimen. A multicenter study. Kiel Lymphoma Study Group.

OBJECTIVE: To describe the clinical course of patients with angioimmunoblastic lymphadenopathy (AILD)-type lymphoma with a sequential treatment with prednisone and COPBLAM/IMVP-16. DESIGN: A multicenter, prospective, nonrandomized trial. SETTING: University medical centers and community hospitals. PATIENTS: Sixty-seven patients were registered, 28 were excluded, and 39 patients were evaluable for response (median age, 59 years; range, 25 to 82 years) (stages I and II, 10%; stages III and IV, 90%; B symptoms, 74%). MEASUREMENTS: Response, survival, and relapse. INTERVENTION: Patients initially received prednisone and no further treatment if a complete remission was achieved. Relapsing or refractory patients were treated with COPBLAM/IMVP-16. Patients with life-threatening tumor progression or extension received COPBLAM/IMVP-16 initially. Treatments were chosen in accordance with tumor extension and response to prednisone. Treatment modalities were not compared. RESULTS: Twenty-eight patients received primary prednisone, 18 received secondary prednisone, and 11 received primary chemotherapy. The complete response rates (with 95% CIs) were 29% (CI, 12% to 46%), 56% (CI, 33% to 79%), and 64% (CI, 36% to 92%), respectively. The median observation time of surviving patients was 28 months (range, 7 to 53). The median overall survival time was 15 months. The probabilities (with 95% CIs) of overall survival, event-free survival, and relapse at 36 months were 40.5% (CI, 24% to 56%), 32.3% (CI, 17% to 47%), and 34.6% (CI, 14% to 56%), respectively. At the time of evaluation, 22 of 39 patients had died, 7 of noninfectious complications and 14 of infections. CONCLUSIONS: Prednisone with or without COPBLAM/IMVP-16 treatment in AILD-type lymphoma leads to complete remissions in about half of the patients and in long-term, disease-free survival for one third.

Adult↗
PubMed1992

Functional and biochemical characterization of a calcium-ionophore-induced state of unresponsiveness in a cytolytic T cell clone.

To characterize the requirements for the induction of an anergic state in immunocompetent cells we examined the effect of an increase in intracellular calcium concentration on the subsequent responsiveness of cytolytic T cells to antigenic stimulation in vitro. Pretreatment of a murine cytolytic T cell clone with the calcium-ionophore A23187 resulted in the induction of an anergic state characterized by a decrease in cytolytic activity and granule exocytosis upon Ag-specific stimulation. Furthermore, IFN-gamma synthesis declined whereas de novo synthesis of a yet unidentified protein with a molecular mass of 33 kDa as well as proliferative response of cells in response to exogenous IL-2 were unaffected. This state of partial unresponsiveness 1) could be prevented by concomitant pretreatment of cells with cyclosporin A or protein synthesis inhibitors and 2) was reversible within 48 h. Biochemical analysis of TCR-induced intracellular activation revealed a block in signal transduction before the activation of protein kinase C because cellular unresponsiveness could be bypassed by the phorbol ester PMA plus the calcium-ionophore A23187. However, phosphatidylinositol turnover was markedly inhibited in unresponsive cells that also did not show a calcium influx on stimulation with concanavalin A. We conclude that a rise in intracellular calcium in cytolytic T cells might not only be necessary for cellular activation but may also trigger the induction of a partial unresponsiveness to antigenic stimulation due to an inhibition in the early phase of signal transduction.

Calcimycin↗
PubMed1992

Proliferation of non-Hodgkin-lymphoma lymphocytes in vitro is dependent upon follicular dendritic cell interactions.

Follicular dendritic cells (FDC) are located within the B-cell follicles of non-malignant lymphatic tissues and within non-Hodgkin-lymphomas (NHL) derived from the germinal centre or the mantlezone. The interactions between FDC and non-neoplastic B-cells have been extensively investigated but so far no data on functional studies with FDC isolated from lymphoma tissue are available. Using an enzyme cocktail to digest lymph nodes from patients with NHL followed by density centrifugation, single cell suspensions enriched in FDC and B-lymphocytes were obtained. In these preparations FDC formed small cellular clusters with an average of five neoplastic lymphocytes for every FDC. Immunocytochemistry with Ki67 revealed that after 24 h of culture 23.7% of the cells within the clusters were in late G1 to M phase. In contrast, only 10.2% of the lymphoma cells scattered outside the clusters were in these activated stages. As visualized by autoradiography, after 72 h of incubation the rate of proliferation was 16.8 times higher for the lymphoma cells involved in cluster formation as compared to those lymphocytes not associated with FDC. The data indicate that in vitro FDC from NHL lymph nodes form a microenvironment favourable for the activation and proliferation of lymphoma cells. The search for cytokines secreted by FDC in lymphoma tissue is under way.

Aged↗
PubMed1992

Follicular dendritic cells in non-Hodgkin-lymphoma express adhesion molecules complementary to ligands on neoplastic B-cells.

In non-Hodgkin-lymphoma (NHL) with nodular growth patterns, follicular dendritic cells (FDC) form a spherical network which contains neoplastic B-cells. In order to dissect the basis of this close FDC/B cell association, the antigenic profile of adhesion molecules expressed by individual FDC and NHL-B-lymphocytes was evaluated. FDC isolated from NHL were found to express C3bi receptors (CD11b), the very late antigen (VLA) alpha-5- and alpha-6-chain (CD49e, CD49f), and the intercellular adhesion molecule-1 (ICAM-1; CD54). Only a percentage of the FDC population was positive for the VLA beta-1- and alpha-3-chain (CD29, CD49c), the vitronectin receptor (CD51) and the vascular cell adhesion molecule-1 (VCAM-1). B-cells obtained from the lymph nodes of patients with centroblastic-centrocytic lymphoma expressed several ligands complementary to the adhesion molecules detected on FDC. These include LFA-1 alpha- and beta-chains (CD11a, CD18), and ICAM-1 (CD54). Surprisingly, monoclonal lymphocytes in the peripheral blood of patients with a leukaemic course of this lymphoma entity were devoid of these antigens. It seems likely then that neoplastic B-cells without CD11a, CD18 and CD54 surface molecules are unable to associate with FDC and now invade other compartments. Thus, the adhesive interactions which do occur between FDC and NHL-B-cells may directly influence the peculiar growth pattern and spread of centroblastic-centrocytic lymphoma.

Antibodies, Monoclonal↗
PubMed1992

[Clinical and prognosis relevance of the Kiel classification of non-Hodgkin lymphomas].

The Kiel classification of non-Hodgkin lymphomas (NHL) identifies distinct entities by morphological and immunological criteria, subdivided into those of low and high grade malignancy and of B- or T-cell subtype. Numerous clinical studies have proven the clinical and prognostic relevance of this classification scheme although the degree of malignancy alone cannot be automatically equated with prognosis. Thus, histological low grade malignancy correlates with favorable response to therapy in all, but with long term survival only in some clearly defined low grade NHL and final cure is achieved in none of them so far. High grade malignancy corresponds to the aggressive spontaneous course of these NHL but is contrasted with the mostly favorable response to therapy and the chance of cure. The immunological T-cell subtype is clearly associated with an inferior prognosis. Additional biological features of NHL, namely chromosomal aberrations and the status of clonality will contribute to a more differentiated view of NHL and will possibly prove to bear prognostic potential.

B-Lymphocytes↗
PubMed1991

Prospective multicenter trial for the response-adapted treatment of high-grade malignant non-Hodgkin's lymphomas: updated results of the COP-BLAM/IMVP-16 protocol with randomized adjuvant radiotherapy.

In a prospective multicenter trial the efficiency of the response-adapted COP-BLAM/IMVP-16 protocol to induce complete remissions (CR) in high-grade malignant non-Hodgkin's lymphomas as well as the prognostic relevance of adjuvant radiotherapy were investigated. From 1986-1989, 548 patients (median age 56 years) with stage II-IV (Ann Arbor) disease were treated with five cycles of COP-BLAM followed by two cycles of IMVP-16. If only a partial remission was obtained at the time of first restaging (RS) after three cycles (delayed response), treatment was switched to IMVP-16 (two to five courses) immediately. Patients achieving CR by the second RS after chemotherapy were randomized to adjuvant radiotherapy or observation. Responses to chemotherapy were 63% CR in patients completing the second RS (N = 350) or 72% if patients achieving late CR by consolidating radiotherapy are added; responses were 58% or 65% if all deaths prior to the second RS are included (N = 50). Overall and relapse-free survival were 71% and 68% at one year and 63% and 61% at two years. Multivariate risk factor analysis proved the early (by first RS) CR response to possess predominant prognostic relevance for survival. A significant advantage of adjuvant radiotherapy over no further treatment for duration of CR is not yet discernible. These results emphasize the importance of a rapidly achieved CR, thus contributing to the design of future trials.

Adolescent↗
PubMed1991

Proliferation of germinal center B lymphocytes in vitro by direct membrane contact with follicular dendritic cells.

In secondary lymphoid organs, follicular dendritic cells (FDC) are located within B cell follicles and germinal centers. Through their cytoplasmic extensions they come into contact with a large number of neighboring lymphocytes. Using an enzyme cocktail to digest human tonsils followed by ultracentrifugation on bovine serum albumin gradients, single cell suspensions were obtained. Immunocytochemistry revealed that 7% of the cells were FDC, 5% T cells, and 5% macrophages. The remaining population were B cells with greater than 95% being of the germinal center phenotype (i.e. CD19-positive, CD39/sIgD negative). After 24 h of culture up to 44% of the lymphocytes were found in clusters centered around FDC. At the start of the culture as well as 24 and 72 h later, between 31 and 55% of the B cells within FDC associated clusters were in late G1 to M phase of the cell cycle. In contrast, less than 10% of the B cells not in contact with FDC (i.e. outside the clusters) were in an activated state. Autoradiography revealed that after three days of incubation the rate of proliferation was 26.2 times higher for the lymphocytes involved in cluster formation as compared to those cells not associated with FDC. Furthermore, the number of viable B cells after a 72 h mitogen-free culture period was determined. By adding FDC to these preparations, 31.9% of the lymphocytes were rescued from dying. These data show that FDC provide a microenvironment which can maintain the viability, activation and proliferation of germinal center B cells in vitro.

Antibodies, Monoclonal↗
PubMed1990

Antigenic phenotyping of human follicular dendritic cells isolated from nonmalignant and malignant lymphatic tissue.

Follicular dendritic cells (FDC) are located within follicles of secondary lymphoid tissue and in lymph nodes of patients with germinal center cell-derived non-Hodgkin lymphomas. Reliable antigenic phenotyping of FDC within tissue sections has been difficult due to simultaneous labeling of the surrounding germinal center cells. Using an enzyme cocktail to digest human tonsils and cervical lymph nodes with subsequent fractionation by albumin gradient centrifugation, cell isolates containing up to 20% FDC were obtained. This preparation allowed the determination of antigenic phenotype on individual FDC. Molecules expressed by FDC were detected by an isotype-specific immunocytochemical double-labeling procedure, i.e. a monoclonal antibody (mAb) specific for FDC (KiM4 or DRC1) in conjunction with a mAb reactive against an additional antigenic determinant. Nonspecific binding of mAb to immunoglobulin Fc receptors located on FDC membranes was avoided by incubation of cells with human IgG aggregates prior to immunostaining. The results revealed that isolated FDC from these lymphoid tissues express transferrin receptors, the intercellular adhesion molecule 1, class II antigens, the B cell antigens CD20 and CD21, and the myelomonocytic properties CD11b and CD14. Immunoglobulin mu or gamma heavy chains and the B cell antigens CD23 and CD24 are detected on 50% of an isolated FDC population. These FDC are negative for the T helper cell antigen CD4, the B cell cell antigens CD19 and CD22, the immunolobulin alpha and delta chains and the S-100 protein. FDC isolated from lymph nodes of patients with low-grade malignant non-Hodgkin lymphoma, identified by DRC1 or KiM4 mAb, presented the same antigenic profile as seen on FDC from nonmalignant tissue. This suggests that FDC from lymphoma tissue isolated in this manner have the same properties as those found in normal tissue.

Antigens, Differentiation↗