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Biomedical subjects

S A Loyson

Publications and source records attributed to S A Loyson.

5 recordsLinked to original sources

A recombinant, fully human monoclonal antibody with antitumor activity constructed from phage-displayed antibody fragments.

A single-chain Fv antibody fragment specific for the tumor-associated Ep-CAM molecule was isolated from a semisynthetic phage display library and converted into an intact, fully human IgG1 monoclonal antibody (huMab). The purified huMab had an affinity of 5 nM and effectively mediated tumor cell killing in in vitro and in vivo assays. These experiments show that nonimmunized phage antibody display libraries can be used to obtain high-affinity, functional, and clinically applicable huMabs directed against a tumor-associated antigen.

Animals↗

Immunohistochemical analysis of decalcified paraffin-embedded human bone marrow biopsies with emphasis on MHC class I and CD34 expression.

AIMS: To identify the stromal structures and haematopoietic cell lineages in normal bone marrow. The optimal conditions were studied for the reactivity of a panel of antibodies, applicable to paraffin sections of decalcified trephine biopsies using antigen retrieval methods. METHODS AND RESULTS: Two methods of antigen retrieval (pepsin and acid citrate buffer) were tested. For the demonstration of most antigens and for reduction of background staining, heating in acid citrate buffer was preferred. In the case of elastase and von Willebrand Factor (factor VIIIrAg) pepsin pre-treatment was optimal, whereas Ulex europaeus agglutinin (UEA-1) and alpha-smooth muscle actin (alpha-SMA) required no pretreatment. Staining patterns obtained after 48 h EDTA decalcification and short electrolytic decalcification were identical. Both methods allowed recognition of HLA-A and HLA-B antigens, isolated CD34+ cells, mono-histiocytic cells (CD68+), myeloid cells (elastase and myeloperoxidase), erythroid cells (glycophorin C) and of megakaryocytic cells (Factor VIIIrAg). A relative simple lymphocyte-subset analysis was possible in decalcified paraffin sections allowing recognition of B-cells (CD20+) and T-cells (CD3+ and CD45RO+) in frequencies comparable to frozen sections. Suitable stromal cell staining was achieved by vimentin and desmin antibodies, whereas the bone marrow capillary network was visualized by CD34, factor VIIIrAg and UEA-1. CONCLUSIONS: This immunohistochemical study indicates that all cellular components of the haematopoietic microenvironment of the bone marrow can be identified in decalcified paraffin sections using antigen retrieval methods and that the time of decalcification can be reduced to 1-1.5 h.

Antigens, CD34↗

Mantle cell lymphoma. A morphological, immunohistochemical and molecular genetic study.

In order to identify helpful markers in the classification of mantle cell lymphoma, a morphological, immunohistochemical and molecular genetic analysis of 41 cases of NHL, originally referred to us as CC, ILL or IDL, was performed. We revised these lymphomas using the strict morphological criteria described in the updated Kiel classification and the more recently described criteria for MCL. The term MCL was used to designate the small lymphocytic B-cell NHL, previously referred to as CC or ILL/ IDL. This revision yielded 20 MCL, 8 CLL, 3 Cb/Cc, 1 CB, 6 IC and 3 MALT lymphomas. The presence of scattered histiocytes was seen in 90% of MCL and 5% of the other cases. No other morphological parameter, besides the used criteria, differentiated between MCL and similar small lymphocytic B cell lymphomas. Helpful immunohistochemical markers to distinguish MCL from similar small lymphocytic lymphomas were CD5+, CD10-, CD23- and Alkaline Phosphatase+. Large fields of dendritic reticulum cells, often in a loose and disrupted arrangement were seen in 82% of MCL and in 19% of the other lymphomas. Analysis with Southern blotting showed a rearrangement in the BCL-1 locus in 12/20 cases of MCL but not in the other 21 lymphomas. Although very specific for MCL, Southern blotting to detect BCL-1 rearrangements is, due to the large number of probes necessary, not of great help in daily practice for routine diagnostic purposes. We conclude that using strict morphological criteria, the diagnosis MCL can be made reliably and that immunophenotyping is helpful in supporting the diagnosis.

Humans↗

Urinary symptoms due to leukemic infiltration of the prostate. A case report.

A patient with chronic lymphocytic leukemia is presented who suffered from urinary obstructive symptoms due to leukemic infiltration of the prostate gland. He was treated with local radiotherapy, which resulted in complete relief of symptoms. Our report indicates that leukemic infiltration of the prostate should be considered in the differential diagnosis in patients with CLL presenting with obstructive symptoms of the urinary tract.

Aged↗