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Biomedical subjects

C A Müller

Publications and source records attributed to C A Müller.

At least 73 records · Page 4Linked to original sources

Polymerase chain reaction monitoring reduces the incidence of cytomegalovirus disease and the duration and side effects of antiviral therapy after bone marrow transplantation.

Culture-based preemptive therapy with ganciclovir was shown to reduce the incidence of cytomegalovirus (CMV) disease after bone marrow transplantation (BMT). Culture techniques did not detect CMV in 12% to 13% of patients before the onset of CMV disease. In a prospective study, 71 patients either received preemptive therapy based on polymerase chain reaction (PCR) technique (37 patients) or on culture assays (34 patients). In both groups, therapy was continued until clinical signs disappeared and PCR negativity was documented. Twenty-two patients in the PCR group and 15 patients in the culture group received antiviral therapy. PCR allowed detection of the virus (median day, +32 v day +49; P = .006) and introduction of antiviral therapy (median day, +44 v day +54; P = .02) earlier than did culture assays. The incidences of CMV disease (2 of 37 v 8 of 34 in PCR group v culture group, respectively; P = .02) and CMV-associated mortality (0 of 37 v 5 of 34 in PCR group v culture group, respectively; P = .02) were decreased, and the duration of ganciclovir therapy (P < .001) was shorter in the PCR-monitored group. Incidence and median duration of severe neutropenia (less than 500/microL) were lower in the PCR group (two v eight episodes, P = .02; median duration, 1.5 v 5 days, P = .04), as was the incidence of nonviral infections during/after antiviral therapy (2 of 37 v 9 of 34; P = .012). Thus, preemptive therapy based on more sensitive detection methods such as the PCR assay reduces the incidence of CMV disease and CMV-related mortality. Additionally, stopping and withholding antiviral therapy in a PCR-negative patient is safe and allows reduction of the duration and side effects of antiviral therapy.

Adolescent↗

Collagen type VI in the human bone marrow microenvironment: a strong cytoadhesive component.

Collagen type VI, which forms characteristic microfibrillar structures, is assembled from three individual alpha(VI) chains that form a short triple helix and two adjacent globular domains. Expression of all three alpha (VI) collagen chains in the human bone marrow (BM) microenvironment could be detected by chain-specific antibodies in tissue sections and in the adherent stromal layer of long-term BM cultures. In functional studies, collagen type VI was shown to be a strong adhesive substrate for various hematopoietic cell lines and light-density BM mononuclear cells. The adhesive site within the molecule seems to be restricted to the triple helical domain of all three alpha (VI) chains, because individual alpha (VI) chains were not active in the attachment assays. Adhesion of the hematopoietic cell lines to collagen VI was dose-dependent and could be inhibited by heparin. Although the triple helix contains several RGD sequences, adhesion of the hematopoietic cell types to collagen VI could be blocked neither by RGD-containing peptides nor by a neutralizing antibody to the beta 1 integrin subunit. In combination with an antiadhesive substrate, the binding properties of collagen VI could be downregulated. These data suggest that this collagen type may play an important role in the adhesion of hematopoietic cells within the BM microenvironment.

Bone Marrow↗

Correlation of interstitial pneumonia with human cytomegalovirus-induced lung infection and graft-versus-host disease after bone marrow transplantation.

In a retrospective analysis lung biopsy specimens obtained postmortem from 30 consecutive allogeneic bone marrow transplant recipients who had died of either either interstitial pneumonitis (IP; 18/30 patients) or various other causes (12/30 patients) were studied for the local presence of human cytomegalovirus (HCMV) by culture, in situ hybridization, polymerase chain reaction (PCR) and immunohistochemistry for HCMV proteins. All patients suffering from IP were found to be HCMV positive in the lung biopsy. PCR revealed the highest sensitivity for HCMV detection in lung biopsies, but in 15/18 PCR-positive samples local HCMV infection could be confirmed by at least one additional technique. All the lung biopsies obtained from the 12 patients without IP were negative for HCMV by all techniques applied, except one with a weak HCMV-DNA signal in the PCR assay. The severity of the clinical, as well as histological and immunohistological alterations in the lung did not correlate with the amount of HCMV-DNA or the number of HCMV-positive cells detected in the biopsy. An increase of HLA-class II antigen and of ICAM-1 expression on the alveolar epithelium, as well as presence of activated CD8+ or CD4+ lymphocytes infiltrating only HCMV-positive lung biopsies revealed T cell-mediated immune reactions to be involved in the pathogenesis of IP. Since all analyzed patients presented with severe acute or extensive chronic graft-versus-host disease (GvHD), but only those with pulmonary HCMV infection developed IP, dissemination of HCMV appears to be the primary requirement for the initiation of IP. GvHD, however, may interfere with normal control of subsequent antiviral immune response and, thus, provoke the immunopathology of IP.

Adolescent↗

Perlecan in human bone marrow: a growth-factor-presenting, but anti-adhesive, extracellular matrix component for hematopoietic cells.

Human perlecan is a heparan sulfate proteoglycan with a large core protein of 467 kDa to which three glycosaminoglycan side chains are attached. It belongs to the heparan sulfate proteoglycan family which has been implicated in strong interactions between developing hematopoietic cells and their microenvironment in the bone marrow. Here we report that perlecan is highly expressed in the human bone marrow, as well as in long-term bone marrow cultures which are thought to mimic hematopoiesis in vitro. Expression of perlecan in this tissue was shown by Northern blotting of the 14-kb mRNA of the core protein and by immunofluorescence stainings. Functionally, perlecan shows a strong anti-adhesive effect on unfractionated bone marrow cells and on various hematopoietic cell lines, repelling the cells from the perlecan-coated area. In contrast, perlecan is adhesive for fibroblasts and endothelial cells. It is suggested that the anti-adhesive site is located within the core protein of perlecan since heparitinase-treated perlecan still shows the repellent effect. Although anti-adhesive for hematopoietic cells, perlecan is able to bind growth factors like granulocyte/macrophage-colony stimulating factor and present them to hematopoietic progenitor cells in a semi-solid colony assay. The functional role of a growth-factor-binding extracellular matrix component in the bone marrow microenvironment with anti-adhesive properties is uncertain but may be related to compartmentalization.

Adult↗

E-cadherin is functionally involved in the maturation of the erythroid lineage.

Differentiation and proliferation of hematopoietic progenitors take place in the bone marrow and is a tightly controlled process. Cell adhesion molecules of the integrin and immunoglobulin families have been shown to be involved in these processes, but almost nothing was known about the involvement of the cadherin family in the hematopoietic system. A PCR screening of RNA of human bone marrow mononuclear cells with specific primers for classical cadherins revealed that E-cadherin, which is mainly expressed by cells of epithelial origin, is also expressed by bone marrow cells. Western blot analysis and immunofluorescence staining of bone marrow sections confirmed this unexpected finding. A more detailed analysis using immunoaffinity columns and dual color flow cytometry showed that the expression of E-cadherin is restricted to defined maturation stages of the erythropoietic lineage. Erythroblasts and normoblasts express E-cadherin, mature erythrocytes do not. A functional role of E-cadherin in the differentiation process of the erythroid lineage was indicated by antibody-inhibition studies. The addition of anti-E-cadherin antibody to bone marrow mononuclear cultures containing exogeneous erythropoietin drastically diminished the formation of erythropoietic cells. These data suggest a non-anticipated expression and function of E-cadherin in one defined hematopoietic cell lineage.

Base Sequence↗

The vascular cell adhesion molecule (VCAM-1) is expressed on a subset of lymphoid and myeloid leukaemias.

The expression of the vascular cell adhesion molecule (VCAM-1), recently identified as cytokine-inducible ligand of the beta 1-integrin VLA-4, was investigated on normal and malignant haemopoietic precursors as well as on haemopoietic cell lines. VCAM-1 was demonstrated on > 20% blasts in 4/22 acute myeloid leukaemia (AML) and 6/10 acute lymphoblastic leukaemia (ALL) specimens but was absent from CD34+ normal bone marrow precursor cells. Interestingly, the VCAM-1+ AMLs classified as M1 and M5 simultaneously expressed N-CAM (CD56), a member of the immunoglobulin family. In ALL, VCAM-1 expression was restricted to Calla+ CD19+ precursors of the c-ALL subtype. VCAM-1 was also found on some cell lines, mainly of the B-lymphocytic type. Furthermore, in 13/20 chronic lymphocytic leukaemia (CLL) samples > 20% of the CD19+ B-lymphocytic precursors carried VCAM-1, which seemed to correlate with more advanced disease. Therefore VCAM-1 expression appeared to characterize leukaemic cells of the B-cell lineage as well as a CD56+ subset of AML. Since its expression was clinically correlated with dermal infiltrates of leukaemic cells in AML and with advanced Rai stages in CLL, VCAM-1 may play a role in enhanced adhesion of the malignant cells to tissues and/or to each other.

Acute Disease↗

Differential expression of adhesion molecules in acute leukemia.

Interactions between hematopoietic cells and the stromal microenvironment are mediated by membrane-bound adhesion molecules. As the expression patterns of these molecules may alter the adhesive qualities of leukemic blasts, leukemic samples were investigated for the expression of beta 1-, beta 2-, beta 3-integrins, CD44, the three selectins and several members of the immunoglobulin family. CD44 (167/169), LFA-3 (158/169), the beta 1-integrins VLA-4 (120/123) and VLA-5 (45/51) and the beta 2-integrin LFA-1 (149/157) were found on > 70% of blasts in most cases of leukemias. Other molecules were restricted to specific differentiation stages and lineage. The beta 2-integrins Mac-1 (CD11b/CD18) and gp 150,95 (CD11c/CD18) were preferentially expressed on M4 and M5 subtypes, and NCAM (CD56) was only found on a subset of acute myeloid leukemias (17/113). Unexpectedly, the beta 1-integrins VLA-1 (1/51), VLA-2 (18/123), VLA-3 (5/43), VLA-6 (15/29) and the E-selectin (2/47) were expressed on > 70% blasts on a subset of leukemias of varied phenotype. These molecules were absent on normal CD34+ bone marrow precursors. The simultaneous analysis generally revealed a higher percentage of positive blasts in the blood than in bone marrow. Our observations therefore suggest that in leukemia these antigens are displayed on a non-adherent population that is defective and is unable to convert to an adherent, functionally active conformational state.

Acute Disease↗

Immunomorphological characteristics of renal cell carcinoma.

Immunomorphological characteristics of 27 renal cell carcinoma (RCC): 18 clear cell, 6 granular (chromophilic), 2 chromophobe, 1 spindle cell (sarcomatoid) as well as of 1 oncocytoma, were analyzed. The investigation was performed on cryostat sections by immunoperoxidase technique applying a panel of monoclonal antibodies which defined: proximal (TNE3, TN5, 5D9) and distal (TN8, TN9, 7C2) tubular antigens; intercellular adhesion molecule 1 (ICAM1); HLA class II (-DQ, -DR and -DP) antigens, intermediary filaments (cytokeratin and vimentin); and antigens on tumour infiltrating mononuclear leucocytes (TT1, TT2 and LeuM3 for CD4, CD8 and CD14 antigens, respectively). All RCC with exception of chromophobe co-expressed cytokeratin and vimentin. In addition, they were usually positive for all proximal and two distal tubular markers (TN8, TN9) indicating primitive cells which could differentiate into the epithelium of both parts of tubule system as the most probable originators of in RCC. Almost all RCC but the chromophobe aberrantly expressed HLA class II antigens which great variability from case to case. The presence of HLA-DR antigens was more intensive and widespread than of HLA-DQ and -DP antigens. Expression of ICAM1 mostly correlated with presence of HLA class II antigens, particularly with -DR on tumour cells of RCC. HLA-DR antigen expression was always more prominent than mononuclear cell infiltrate (among which macrophages prevailed over T cells) which could suggest that increased histocompatibility antigen expression precedes mononuclear cell influx. In contrast to all other RCC, chromophobe tumours had quite distinct features revealing the most intense reaction with 7C2 (MAb that produced the weakest reaction with other tumour types), absence of vimentin and very weak reaction with antibodies for HLA class II Ag and ICAM1.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenoma, Oxyphilic↗

Treatment of steroid-resistant graft-versus-host disease after allogeneic bone marrow transplantation with anti-CD3/TCR monoclonal antibodies.

Acute graft-versus host disease (GVHD), one of the major complications of allogeneic bone marrow transplantation (BMT), occurs in 30-50% of all patients transplanted from HLA-identical sibling donors and in 50-80% of all patients transplanted from an unrelated or HLA-mismatched family donor, despite GVHD prophylaxis with methotrexate and cyclosporin. We report our experience with OKT3/BMA031 treatment in 14 patients with severe steroid-resistant GVHD following allogeneic BMT. Three of 5 patients treated in the early post-transplant period with OKT3 remitted and 2 of 3 became long-term survivors. Two patients treated for extensive chronic GVHD showed only minor responses. Five of 7 patients treated with BMA031 showed a partial remission; no complete remission was seen after treatment with this antibody. Shortly after the introduction of OKT3 or BMA031 therapy a rapid decline of the lymphocyte count, especially the CD3+ subset, was observed coinciding with a relative increase of CD56+ lymphocytes and of gamma/delta TCR+ T cells. Increasing numbers of CD3+ lymphocytes preceded recurrence of acute GVHD in three patients. In contrast, persisting CD3-lymphocytopenia was associated with complete clearance of acute GVHD. The incidence of infectious complications following OKT3 or BMA031 therapy was high (42%). Thus, to improve treatment results of severe acute GVHD, prophylactic or pre-emptive strategies are required to reduce the rate of fatal viral and fungal infections.

Acute Disease↗

[Long term follow up of lymphoplasmocytoid immunocytoma].

Two women with lymphoplasmocytoid immunocytoma (Waldenström's macroglobulinaemia) have been followed up, one for 23 years and the other for 18. In the first patient the disease presented at the age of 40 years with lassitude and paraesthesiae. Investigation revealed monoclonal IgM-lambda with a serum IgM of 3350 mg/dl and marrow infiltration by lymphoplasmocytoid cells. As there were no symptoms, apart from migraine attacks which responded well to plasmapherese, and because haemopoiesis was unaffected and the lymph nodes were not enlarged, no cytostatic has so far been given. The proportion of lymphoplasmoid cells in the marrow is at present 50%. In the second patient the disease presented at the age of 33 with involvement of stomach and lung, and a conglomerate tumour in the upper abdomen. The serum showed an M-gradient together with raised IgM (3056 mg/dl). Chemotherapy (COPP protocol) and local irradiation of the stomach achieved full remission. At intervals of several years there have been histologically confirmed recurrences in the hypophyarynx, ovaries, hilum of left lung and, most recently, in the upper abdomen once more. These have been successfully treated by resection and local radiotherapy (hypopharynx), operation followed by chemotherapy (COP protocol) (ovaries, upper abdomen) or by radiotherapy alone (hilum of lung-50 Gy).

Adult↗

The possible role of G-CSF in the pathogenesis of Sweet's syndrome.

Sweet's syndrome (SS) is characterized by the clinical features of fever, leucocytosis, neutrophilia and the sudden onset of asymmetric, often very painful skin lesions and dense dermal infiltrates of mature neutrophils without signs of vasculitis. Apart from idiopathic cases the disease is frequently associated with hematological malignancies, but it may also be observed in patients with solid tumors, mainly tumors of the genito-urinary tract. In the past, numerous theories have been proposed to explain the pathogenesis of this rare disease. SS has been interpreted as a direct response to mechanical and chemical irritants, an infectious disease or a disorder of neutrophilic chemotaxis and/or phagocytosis, but most often it has been described as a hypersensitivity reaction. Each of these theories can account for particular symptoms, but none of them reconciles the dominating clinical and laboratory features of the disease. Furthermore recently published casuistic observations suggest the involvement of certain cytokines in particular G-CSF and Il-6 in the pathogenesis of the disease, which might explain many of the observed clinical and laboratory findings. The following article summarizes these data and gives a review of the current literature.

Granulocyte Colony-Stimulating Factor↗

AML: immunophenotypic heterogeneity and prognostic significance of c-kit expression.

Antigenic profiles in AML that have generally accepted prognostic significance, and allow treatment stratification, have not yet been defined. In a previous report of Ashman et al., the proto-oncogene c-kit defined by binding of the moab YB5.B8 was expressed on about one third of AML cases, mainly of the undifferentiated FAB-subtypes and associated with poor prognosis and overall survival. In this study, the moab 17F11 also directed against the c-kit structure stained 41/47 AML and 6/8 CML blast specimens, whereas all investigated 40 ALL samples were c-kit negative. c-kit was not restricted to any particular, undifferentiated FAB-subtype, but found in 9/9 AML-M0/M1, 18/19 AML-M2, 0/1 AML-M3, 11/13 AML-M4 and 3/5 AML-M5 subtypes. Immunophenotypical analysis showed no restriction of c-kit expression to immature, CD34+ precursors, but c-kit was also expressed on CD4+ CD34- precursor cells differentiating towards the monocyte lineage. In addition, multi-color labelings revealed an extraordinary heterogeneity of concomitant antigen expression on c-kit+ cells 10/36 c-kit+ CD34+ samples expressing CD56 and 16/36 c-kit+ CD34+ samples being CD7 positive; two c-kit+ CD34+ specimens carried the B-cell antigen CD19. In correlation to clinical outcome c-kit expression as single parameter was not predictive for poor response to therapy and short survival as previously suggested.

Aged↗

[Osteosynthesis of proximal femoral fractures with the modular interlocking system of unreamed AO femoral intramedullary nail. Initial clinical results].

The unreamed femoral nail system (UFN) features highly versatile proximal interlocking options for the treatment of a wide range of femoral fracture patterns and combinations. Besides standard interlocking modes for diaphyseal fractures, special interlocking options for subtrochanteric fractures and ipsilateral neck/shaft fractures are available. Two aiming arms can be attached to the insertion handle of the nail in a modular fashion. The standard aiming arm is designed for transverse static or dynamic locking. The special aiming arm permits spiral blade, 130 degrees, and miss-a-nail interlocking. From August 1992 to July 1994, in 10 out of 55 UFN implantations the special interlocking options were used. In 9 subtrochanteric fractures the spiral blade interlocking and in one ipsilateral neck/shaft fracture the miss-a-nail cancellous screw interlocking was applied. ASIF type A fractures with closed soft tissue damage prevailed. Fracture healing was uneventful and no implant complications or loss of reduction have been observed.

Adult↗

Modulation of p145c-kit function in cells of patients with acute myeloblastic leukemia.

The function of the steel factor receptor, p145c-kit, in patient-derived acute myeloblastic leukemia (AML) cells was investigated. Steel factor stimulation of AML cells coexpressing p145c-kit and the progenitor cell antigen CD34 resulted in complete receptor down-regulation, a marked decrease of CD34 antigen expression, and the induction of the granulocyte lineage antigen CD15. These changes in surface marker expression paralleled morphological differentiation to granulated blasts and promyelocytes. Interestingly, the same phenotype was achieved by IL-3 stimulation of AML cells. p145c-kit extracellular domain-specific antibodies had either blocking or enhancing effects on ligand binding, receptor phosphorylation and down-regulation, and induction of cell proliferation. Correlations of these phenomena with distinct effects of antibody stimulation on cell substrate phosphorylation provide clues for the dissection of the p145c-kit signal and the analysis of its relevance for AML.

Animals↗

Lymphocytopenia as an unfavorable prognostic factor in patients with cytomegalovirus infection after bone marrow transplantation.

Sixty-three recipients of an allogeneic marrow transplant were screened for the occurrence of cytomegalovirus (CMV) infection and clinical parameters possibly predicting the development of CMV disease in a retrospective study. Blood and urine samples obtained from these patients were screened weekly after bone marrow transplantation (BMT) for the presence of CMV by polymerase chain reaction (PCR) and virus culture technique. Forty-six of the 63 patients studied were found to be CMV-positive by PCR technique in blood and urine samples at a median of 29 days after BMT. In 33 of these 46 patients, CMV could be cultured from urine samples and 16 of the 46 had culture-positive viremia. Twenty-eight of these 46 PCR-positive patients developed CMV disease. Whereas PCR assays showed an optimal negative predictive value and sensitivity for the development of CMV disease, their positive predictive value was 61% and could not be remarkably increased when culture-proven viruria (64%) and viremia (69%) were considered. Acute graft-versus-host disease (GVHD) grade 2 to 4 (P < .05), but not underlying disease, conditioning therapy, or GVHD prophylaxis, was associated with CMV infection. On day +49, a remarkable decrease (P < .001) in the lymphocyte count, as well as in the absolute number of CD4+, CD8+, and CD56+ lymphocytes, occurred only among the patients who later developed CMV disease. The decrease of all of these cell counts, but predominantly the CD4+ T cells, to less than 100/microL on day +49 after BMT showed a very high positive predictive value (100%) for the development of CMV disease in patients with PCR-proven viremia. Persisting CD4 lymphopenia after antiviral therapy was only observed in patients who finally died of CMV disease. Thus, immunophenotyping of the patients after BMT in addition to a highly sensitive virus detection assay might help to identify patients at high risk to develop CMV disease and indicate the need for additional adoptive immunotherapy.

Adolescent↗