Biomedical subjects

M L Hansmann

Publications and source records attributed to M L Hansmann.

At least 91 records · Page 5Linked to original sources

PubMed1995

Characterization of CD34+ human hemopoietic progenitor cells from the peripheral blood: enzyme-, carbohydrate- and immunocytochemistry, morphometry, and ultrastructure.

Following an immunomagnetic isolation and enrichment procedure, CD34+ cells were harvested from the peripheral blood of about 50 healthy donors. A battery of cytochemical staining reactions, monoclonal and carbohydrate-specific antibodies, proliferation markers and lectins was applied on smears and sections from paraffin-embedded pellets. Additionally, a morphometric analysis and ultrastructural investigation was carried out. More than 95% of the total yield of progenitor cells expressed CD34 and CD43 (MT1) and of these about 90% CD45 (LCA) and 25% CD45A (MT2). The CD34+/CD45RA-population was thought to represent very primitive, probably not lineage-restricted stem cells. On the other hand, reactivity with ANAE, CD11c, CD15, CD20, Ret40f, KiM1P, and CD61 (ranging between 1 to 20%) was considered to indicate a transition into more differentiated elements of hemopoiesis. The failure to detect any staining with proliferation markers (Ki-67/MIB 1, PCNA, KiS1) was in keeping with a quiescent status. Carbohydrate antigens revealed a pattern which underlines the fact that the CD34 and CD43 antigens belong to the family of heavily O-glycosylated sialomucins. Blood group antigens which are located at the peripheral regions of mucin-oligosaccharides (H type 2, Lewis, Lewis) could be demonstrated, but not A, B, Sialyl-Lewis and Lewis. Morphometric analysis revealed that CD34+ progenitors were larger than small lymphocytes. Electron microscopy showed a relatively primitive cytoplasmic organization and numerous tiny magnetic beads clustered at the plasma membrane.

Adult↗

PubMed1995

Hodgkin cells accumulate mRNA for bcl-2.

BACKGROUND: The bcl-2 oncogene is able to prevent cells from apoptosis. Overexpression of the bcl-2 protein seems to be important for the pathogenesis of follicular center cell lymphomas, in which both protein and mRNA usually show high levels. In addition, the expression of the Epstein-Barr virus-encoded late membrane protein up-regulates the bcl-2 protein in cell lines. The aim of the current study was to investigate the expression of the bcl-2 oncogene in Hodgkin's disease both at the protein and mRNA level in correlation with the expression of the late membrane protein. EXPERIMENTAL DESIGN: Thirteen cases of all histologic types of Hodgkin's disease, six cases of chronic nonspecific lymphadenitis, three tonsils with follicular hyperplasia, seven cases of follicular small cleaved cell lymphoma, and six cases of follicular large cell lymphoma, were analyzed. We designed a novel digoxigenin-labeled oligonucleotide probe complementary to bcl-2 mRNA for nonisotopic in situ hybridization. Bcl-2 oncoprotein and late membrane protein expression were determined by immunohistochemistry. The presence of the 14;18 translocation was analyzed by PCR for the major breakpoint region. RESULTS: The main finding was that, irrespective of subtype, the vast majority of Hodgkin cells express abundant bcl-2 mRNA. Oncoprotein expression, however, varied from case to case, with the highest prevalence in the nodular sclerosing subtype, and showed no strict correlation with the late membrane protein. In our case, no 14;18 translocation could be found in Hodgkin's disease. CONCLUSIONS: Hodgkin cells in all types of Hodgkin's disease demonstrated high levels of bcl-2 mRNA, while the bcl-2 protein expression was inhomogenous. In nodular lymphocyte predominant type, the bcl-2 mRNA and protein pattern is comparable to germinal center cells. This finding is a further argument for the germinal center cell origin of this type of Hodgkin's disease.

Base Sequence↗

PubMed1995

Detection of clonal lambda light chain gene rearrangements in frozen and paraffin-embedded tissues by polymerase chain reaction.

A method was established to detect clonal lambda light chain gene rearrangements in peripheral blood lymphocytes and frozen or paraffin-embedded tissues. V lambda-gene-family-specific primers were used together with a J lambda primer mix in separate reactions to amplify V lambda gene rearrangements by the polymerase chain reaction. Clonal lambda gene rearrangements were detected in seven of seven lambda-expressing B cell leukemias, in four of five lambda-expressing non-Hodgkin's lymphomas with frozen tissues, and in seven of nine cases of lambda-expressing non-Hodgkin's lymphomas for which formalin-fixed, paraffin-embedded specimens were available. Clonality of amplified polymerase chain reaction products was confirmed by sequence analysis for several cases. The present study shows that it is possible to amplify clonal lambda gene rearrangements in the majority of lambda-expressing B cell leukemias and lymphomas. The method described here, therefore, is a useful supplement to the previously described approach of VH and VK gene amplification to detect clonal B cell populations and allows the study of V lambda gene usage and somatic mutation in lambda-expressing normal and malignant B cells.

Amino Acid Sequence↗

PubMed1995

Detection and quantification of transforming growth factor beta (TGF-beta) and platelet-derived growth factor (PDGF) release by normal human megakaryocytes.

Transforming growth factor beta (TGF-beta) and platelet-derived growth factor (PDGF) are known as protein cytokines involved in differentiation as well as in maturation processes within the hematopoietic system. Both enhance the proliferation and/or collagen synthesis in fibroblasts and are found within the alpha-granules of megakaryocytes. To learn more about the regulation mechanisms involving synthesis and secretion of these cytokines it is important to develop suitable experimental conditions. We have applied the reverse hemolytic plaque assay (RHPA) to CD61+ megakaryocytes prepared from bone marrow of hematologically normal patients. By means of the RHPA, the spontaneous and stimulated secretion of TGF-beta 1 and PDGF could be analyzed at the single cell level. According to morphometric analysis, predominantly small megakaryocytes including precursors (pro- and megakaryoblasts) secrete TGF-beta 1 and PDGF under physiological conditions. Furthermore, the proportion of actively secreting megakaryocytes increased significantly following treatment with recombinant human (rh) IL-3 for 8 h. A slight induction was also appreciated after stimulation with interleukins rhIL-1 or rhIL-11. Because IL-3 as well as IL-11 are known as efficient growth factors for human megakaryocytes in vitro, our data provide insights into the regulatory mechanisms involved in megakaryopoiesis and the development of myelofibrosis.

Bone Marrow Cells↗

PubMed1994

Antidisialoganglioside ricin A-chain immunotoxins show potent antitumor effects in vitro and in a disseminated human neuroblastoma severe combined immunodeficiency mouse model.

Several monoclonal antibodies (mAbs) were screened on different neuroblastoma cell lines to evaluate ricin A-chain immunotoxins for possible use against human neuroblastoma. Four mAbs were identified that exhibited high antitumor activity against neuroblastoma cell lines as measured in an indirect cytotoxicity assay. These mAbs, including 14G2a (antidisialoganglioside), ch14.18 (a humanized switch variant), BW704 (antidisialoganglioside), and chCE7 (anti-glycoprotein of M(r) 190,000), were subsequently linked via the bivalent linker N-succinimidyloxycarbonyl-alpha-methyl-alpha-(2-piridyldithio++ +)toluene to deglycosylated ricin A chain. The most potent immunotoxin, 14G2a.dgA, inhibited the protein synthesis of neuroblastoma cell lines IMR5 and NMB by 50% at concentrations of 6 x 10(-12) M. To test the antitumor efficacy of these immunotoxins in vivo, we developed a disseminated human neuroblastoma model in severe combined immunodeficiency mice. Treatment of tumor-bearing mice with 14G2a.dgA 12 days after tumor challenge resulted in a significant prolongation of survival as compared with phosphate-buffered saline-treated controls (16.8 versus 6.5 weeks). We conclude that ricin A-chain immunotoxins might be of potential use in the treatment of human neuroblastoma.

Animals↗

PubMed1994

Hodgkin disease: Hodgkin and Reed-Sternberg cells picked from histological sections show clonal immunoglobulin gene rearrangements and appear to be derived from B cells at various stages of development.

Hodgkin disease (HD) is characterized by a small number of putative malignant cells [Hodgkin and Reed-Sternberg (HRS) cells] among a background of lymphocytes and histiocytes. The lineage of HRS cells is still elusive and a clonal origin of these rare cells has not formally been demonstrated. We isolated HRS cells by micromanipulation from histological sections of three cases of Hodgkin lymphoma (each representing a distinct subtype of the disease) and analyzed individual cells for immunoglobulin variable (V) gene rearrangements by PCR. In each of the three cases a single heavy-chain V (VH) (and in one case, in addition, a kappa light-chain) gene rearrangement was amplified from the HRS cells, identifying these cells as members of a single clone. A potentially functional VH rearrangement was obtained from a case of nodular sclerosis HD. Somatic mutations and intraclonal diversity in the VH genes indicate a germinal center B-cell origin of the HRS cells in a case of lymphocyte-predominant HD, whereas in a case of mixed-cellularity HD the sequence analysis revealed only nonfunctional V gene rearrangements, suggesting a pre-B-cell origin. This indicates that HRS cells can originate from B-lineage cells at various stages of development.

Adult↗

PubMed1994

Successful treatment of disseminated human Hodgkin's disease in SCID mice with deglycosylated ricin A-chain immunotoxins.

To evaluate the effects of deglycosylated ricin A-chain (dgA) immunotoxins against disseminated Hodgkin's lymphoma, we used RFT5.dgA (CD25) and IRac.dgA (70 kD) to treat L540Cy Hodgkin cells in severely immunodeficient SCID mice. In this model, more than 90% of the animals developed multiple lymphomas in various organs such as the lymph nodes, liver, bone marrow, and extranodal sites that killed untreated animals after a mean survival time (MST) of 36.3 days. A single intraperitoneal injection of 8 micrograms of either immunotoxin rendered 95% (RFT5.dgA) and 93% (IRac.dgA), respectively, of mice tumor-free when applied 1 day after tumor challenge. The MST of the RFT5.dgA-treated group was extended by more than 80 days (P < .00001). SCID mice treated 12 days after tumor challenge had lower remission rates (46%), suggesting that the antitumor effect of the immunotoxins depends on the number of tumor cells present. We conclude that ricin A-chain immunotoxins have potent antitumor effects against disseminated Hodgkin's tumors in SCID mice and that this model is ideally suited for the evaluation of different immunotoxin treatment modalities.

Animals↗

PubMed1994

Cytokine release by human bone marrow cells: analysis at the single cell level.

Regulation of haemopoiesis is closely mediated by a number of growth factors in the marrow microenvironment. The identification of the cell type secreting these regulatory polypeptides is difficult due to the heterogeneity of bone marrow cells. To analyse the release of haemopoietic growth factors by normal human bone marrow cells at the single cell level, we employed the reverse haemolytic plaque assay (RHPA). Freshly isolated human marrow cells were examined for the release of interleukin-1 alpha (IL-1 alpha), IL-3, IL-6 and granulocyte-monocyte colony stimulating factor (GM-CSF). In order to identify various cytokine-secreting cell types, the RHPA was combined with immunocytochemical or enzymatic staining. The total of secreting marrow cells as well as the amount of several secretory haemopoietic subpopulations could be determined with this technique under various conditions. Following incubation with pure serum-free medium without addition of any mediator, only few cells secreting either IL-1 alpha, IL-3, IL-6 or GM-CSF could be observed. After 2 h incubation with recombinant human-IL-1 alpha (rhIL-1 alpha) (10.0 ng/ml) or rhGM-CSF (10.0 pg/ml) the number of cytokine-secreting cells significantly increased for all secretory products tested. Using cytochemical staining reactions, we were able to identify 55% of all cells secreting a specific cytokine. Glycophorin C-positive erythropoietic cells turned out to be the largest fraction (up to 89%) of cytokine-releasing haemopoietic cells, followed by neutrophil granulocytes (between 6 and 48%), and monocytes/macrophages (between 4 and 23%). Only few CD 61-positive cytokine-secreting megakaryocytes could be detected. Dose- and time-dependent kinetics after stimulation with rhGM-CSF revealed that the bulk of secretory activity originates from haemopoietic or rather from erythropoietic cells following low level stimulation and after short stimulation time. Thus, our data are in keeping with the assumption, that especially erythropoietic cells are producing a repertoire of cytokines that is thought to exhibit regulatory functions within marrow microenvironment. In the present study the RHPA is presented as an appropriate tool for measuring cytokine release not only of cells of the haematopoietic system but also of other tissues, for example solid tumours or malignant lymphomas.

Bone Marrow↗

PubMed1994

Monocytoid B-cells occurring in Hodgkin's disease.

In contrast with various forms of lymphadenitis, the presence of reactive monocytoid B-cells (MBCs) has only rarely been reported in Hodgkin's disease (HD). In order to analyse their occurrence in HD, we reviewed 120 cases before or after treatment. MBCs were identified morphologically and immunohistochemically in 8 cases (nodular paragranuloma, n = 2; nodular sclerosis, n = 2; and interfollicular mixed cellularity HD, n = 4). Acute toxoplasmic, cytomegalovirus, or Epstein-Barr virus (EBV) infections were excluded by serological tests and immunohistochemistry. MBCs were negative by immunostaining for EBV encoded latent membrane protein, while Sternberg-Reed and Hodgkin's cells expressed positivity in 50% of cases. MBCs were only identified in cases with partial or incomplete lymph node infiltration by HD together with an activated B-zone of residual non-infiltrated tissue. The relation of MBCs and HD infiltrates followed three distinct patterns: large HD infiltrates without any connection to MBC foci; small areas containing various numbers of Sternberg-Reed and Hodgkin's cells at the border between MBC foci and surrounding lymphoid tissue; and HD infiltrates within at least some MBC clusters. The data obtained suggest that MBCs occurring in HD represent a transient phenomenon associated with a B-zone activation irrespective of treatment and that they are usually not histogenetically related to HD.

Antibodies↗

PubMed1994

Angioimmunoblastic lymphadenopathy type of T-cell lymphoma and angioimmunoblastic lymphadenopathy: a clinicopathological and molecular biological study of 13 Chinese patients using polymerase chain reaction and paraffin-embedded tissues.

The morphological classification of angioimmunoblastic lymphadenopathy (AILD) or T-cell lymphoma of AILD-type (AILD-TCL) is still a subject of considerable difficulty and controversy. The aim of the current study was to examine the value of clinical, morphological, immunohistochemical variables in paraffin-embedded tissues in predicting the clonality of the respective lesion. Fifteen lymph node biopsies derived from 13 patients from Chengdu, China, were diagnosed as AILD or AILD-TCL and included in this study. The specimens were examined using a panel of monoclonal antibodies and a scoring system of morphological features. Clonality of the paraffin-embedded material was investigated using a novel polymerase chain reaction-technique to amplify rearranged T-cell receptor (TCR)-gamma sequences. Additional experiments were carried out to investigate the presence of clonal rearrangements of the immunoglobulin heavy chain (IgH) locus. We found clonal rearrangements of the TCR-gamma locus in 9 out of 15 lymph node biopsies. In 3 patients, the predominant cell clones carried clonal IgH and TCR-gamma rearrangements whereas 1 patient with polyclonal TCR-gamma pattern displayed IgH-monoclonality. The statistical evaluation of morphological and immunohistochemical data indicated that no single variable was able significantly to predict the clonality of the lesion. Furthermore, demonstrable clonality for the TCR-gamma or the IgH loci of a lesion did not correlate with a bad clinical course. Our data correlate with findings of other studies investigating AILD-TCL in Caucasian populations.

Adult↗

PubMed1994

[Determination of clonality in lymphoproliferative diseases using polymerase chain reaction].

The diagnosis of lymph node lesions frequently requires the employment of additional studies. Lineage and clonality can be regarded as the most crucial diagnostic parameters. In some cases the diagnosis remains ambiguous even after immunohistochemistry and molecular biologic techniques have to be applied. These molecular biologic techniques are based on specific rearrangements of the immune genes that occur during T- and B-cell development. Whereas Southern blotting has become a standardized and reliable means for the detection of lineage and clonality, the limited availability of fresh frozen material frequently restricts its clinical applicability. The polymerase chain reaction has facilitated the investigation of immune gene rearrangements in formalin-fixed and paraffin-embedded tissue samples. This communication reviews the recent developments in this field.

Chromosome Aberrations↗

PubMed1994

Incidence of Epstein-Barr virus bcl-2 expression and chromosomal translocation t(14;18) in large cell lymphoma associated with paragranuloma (lymphocyte-predominant Hodgkin's disease).

Seven cases of large cell lymphoma (LCL) developing simultaneously or secondarily to lymphocyte-predominant Hodgkin's disease (nodular paragranuloma [NP]) were investigated for the presence of Epstein-Barr virus genomic material and the chromosomal translocation t(14;18) involving the major breakpoint region of the bcl-2 gene using the polymerase chain reaction on paraffin-embedded material. The translocation t(14;18) and Epstein-Barr virus could not be demonstrated in any case. The expression of the bcl-2 oncogene product was investigated using immunohistochemistry. Only in one case were the lymphocytic and histiocytic cells positively stained with the bcl-2 antibody, whereas the associated LCL demonstrated a completely negative immunoreaction. In another case the LCL had a positive immunoreaction with this antibody and the corresponding lymphocytic and histiocytic cells were completely negative. We conclude that Epstein-Barr virus infection is rare or absent in NP and in the LCLs associated with NP. The chromosomal translocation t(14;18) does not seem to be a factor in the transformation of NP into LCL.

Adult↗

PubMed1994

Follicular dendritic cells have prognostic relevance in Hodgkin's disease.

The authors' previous study showed the presence of follicular dendritic cell (FDC) networks--though altered--in neoplastic areas, not only in the nodular lymphocyte predominance type, but also in other types of Hodgkin's disease. The present retrospective study was performed on 102 patients to determine whether the presence or absence of FDC networks, or parts of them, in neoplastic areas has prognostic relevance in Hodgkin's disease. Follicular dendritic cells were visualized with the monoclonal antibody Ki-FDC1P, which selectively stains FDCs in paraffin-embedded tissues. Univariate statistical analysis, in which nodular sclerosis (NS) and mixed cellularity (MC) types were combined, showed three prognostically different groups: the best prognosis was associated with nodular lymphocyte predominance cases; the worst with FDC-negative NS or MC cases; and an intermediate prognosis with FDC-positive NS or MC cases. In the NS group, the prognosis of FDC-positive cases was better than that of FDC-negative cases. After multivariate analysis, stepwise modeling identified three prognostic factors at diagnosis: stage (P = .001), FDC status (P = .001), and age (P = .06). The authors conclude that in the most common types of Hodgkin's disease (nodular lymphocyte predominance, NS, and MC), FDC status in the neoplastic area(s) bears prognostic relevance, a positive FDC status predicting a favorable prognosis and a negative FDC status an unfavorable one.

Adolescent↗

PubMed1994

Detection of T-cell clonality in paraffin-embedded tissues.

In lymph node diagnosis, difficulties are frequently encountered with the differential diagnosis of reactive and neoplastic T-cell proliferations. Immunohistochemistry is of limited use, and fresh frozen material for DNA studies is not available in many cases. We have established a polymerase chain reaction (PCR) technique to amplify rearranged T-cell receptor (TCR)-gamma sequences from paraffin-embedded material. Our method differs from other techniques previously described in that it uses four sets of family-specific variable (V)gamma primers. Clonality of the investigated T cells is reflected not only by the varying lengths of amplified products but also by differences in the relative amount of rearranged V gamma families. Preliminary studies indicate that this approach can provide information about the presence of predominant T-cell clones within the sample and thus help to classify the lymph node lesion. With this technique we were able to confirm clonality in seven of 12 T-cell lymphomas in paraffin-embedded tissues.

Adult↗

PubMed1994

Castleman's disease. Differences in follicular dendritic network in the hyaline vascular and plasma cell variants.

Twenty-seven cases of the hyaline vascular variant and 10 cases of the plasma cell variant of Castleman's disease were studied with the paraffin resistant monoclonal antibodies Ki-FDC1p and/or Ki-M4p against follicular dendritic cells. Studies with the monoclonal antibody Ki-M9, for the detection of sinus lining cells, were also performed on the available frozen tissue in four cases of the hyaline vascular variant. In nine of the 10 plasma cell variant cases, the predominant type of follicular dendritic cell network was similar to that seen in normal or reactive germinal centres. In contrast, the hyaline vascular variant demonstrated either an expanded, disrupted, follicular dendritic cell network (10 cases) or multiple tight collections of follicular dendritic cells (16 cases). Sinus lining cells were not detected in the four cases studied. The difference in the predominant type of dendritic meshwork is an additional distinguishing feature to separate the plasma cell and hyaline vascular variants of Castleman's disease. The patterns of dendritic network seen in the hyaline vascular type, together with the absence of sinus lining cells, appear to favour the hamartoma theory proposed for this variant.

Castleman Disease↗

PubMed1994

Magnetic activated cell sorting (MACS)--a new immunomagnetic method for megakaryocytic cell isolation: comparison of different separation techniques.

Megakaryocytes are difficult to isolate because of their fragility, their tendency to aggregate, and their varying sizes. For purification of cells at different stages of maturation and of different sizes (ploidy classes) we developed an immunomagnetic cell sorting method (MACS) to enrich the whole spectrum of the megakaryocytic cell lineage. The use of small magnetic beads coupled to various antibodies and labelling with fluorescent antibodies allowed direct analysis of enrichment and evaluation of the isolated fraction without further staining or detachment procedures. CD 61 (Y2/51), a monoclonal antibody directed against platelet glycoprotein IIIa, was employed to perform the separation procedure. An enrichment up to 47% of CD 61-positive cells with an average of 37% and a recovery rate of 37% was obtained by using the MACS technique. Pre-enrichment by Percoll density centrifugation, followed by MACS separation, resulted in an enrichment of 65% and a recovery rate of 67%. The relative amount of small megakaryocytic cells in only MACS-enriched cell populations, however, was higher than in Percoll/MACS fractions. As a parameter of vitality we tested cytokine secretion of the enriched megakaryocytes in reverse haemolytic plaque assays. Secretion of IL-1, IL-6, GM-CSF, and PDGF with and without stimulation by phorbol myristate acetate was demonstrable at the single cell level.

Bone Marrow Cells↗

PubMed1994

[Detection of T-cell receptor gamma chain V gene rearrangements in angioimmunoblastic lymphadenopathy type T-cell lymphoma by PCR and family specific primers].

Using PCR method and family specific primers for T-cell receptor gamma chain V gene, the T-cell colonalities of 12 cases of AILD-TCL were analyzed. The results showed monoclonal DNA amplification patterns of TCR gamma in all 12 cases (13 specimens), whereas the DNA from normal peripheral lymphocytes and 2 samples of atypical lymphoid hyperplasia showed polyclonal rearrangement patterns. Our results suggest that AILD-TCL is a monoclonal proliferative disorder originating from T-cell. The PCR method and family specific primers could successfully amplicate the template DNA from paraffin sections, so it is a sensitive, simple and rapid method for routine hematopathologic studies.

Adult↗

PubMed1994

An unusual pattern of lymph node involvement in mycosis fungoides simulating neoplastic follicles.

We describe an unusual pattern of lymph node involvement in a case of mycosis fungoides. The neoplastic proliferation formed pale nodules composed of small, irregular lymphoid cells, features that, on routine paraffin sections, suggested neoplastic follicles and a B-cell phenotype. The correct diagnosis was established by immunohistochemical studies that demonstrated a T-cell phenotype. Polymerase chain reaction for rearrangement of the T-cell receptor gamma gene confirmed that the proliferation was monoclonal. This case demonstrates that both architectural pattern and cytologic features may be unreliable in predicting immunologic phenotype. Immunologic marker studies and careful attention to the clinical history are vital to classify lymphoproliferative disorders correctly.

Aged↗