Search PubMed⌕ Search

Biomedical subjects

M E Peetermans

Publications and source records attributed to M E Peetermans.

At least 37 records · Page 2Linked to original sources
PubMed1991

Stromal populations and fibrosis in human long-term bone marrow cultures.

An immunofluorescence study of the adherent layer of human long-term bone marrow cultures (HLTBMC) revealed the following surface markers on the different stromal cell populations: stromal fibroblastic cells CD10+, FIB86.3+, CD13+, CD71+; adipocytes CD10+, FIB86.3-, CD13+, CD71-/+; and macrophages CD10-/+, FIB86.3+, CD13+, CD71-/+, CD14+, CD33+, CD25+, HLA-DR+, CD4+, CD19+, CD45+. The markers of the stromal fibroblastic cells in HLTBMC were similar to those of twice-passaged fibroblasts not only from bone marrow and spleen, but also from a hemopoietic non-supportive organ such as the skin. Some of the cultured human umbilical vein endothelial cells used as controls were found to be CD25+, demonstrating for the first time the interleukin-2 receptor p55 chain on normal non-hemopoietic cells. The stromal fibroblastic cells are overrepresented compared to the small non-macrophage hemopoietic cell population in the adherent layer of HLTBMC. In addition, silver staining revealed an increased reticulin content in most of the HLTBMC. An excessive growth of stromal fibroblastic cells and an excessive deposition of their product, the reticulin fibers, are the hallmark of myelofibrosis. The finding of equivalent observations in HLTBMC suggests that the hitherto unexplained, premature quenching of hemopoiesis in HLTBMC might at least partly be due to mechanisms similar to those operating in myelofibrosis in vivo.

Antigens, CD↗
PubMed1990

Pentostatin in refractory chronic lymphocytic leukemia: a phase II trial of the European Organization for Research and Treatment of Cancer.

Pentostatin was used to treat 26 patients with advanced B-cell chronic lymphocytic leukemia resistant to conventional treatment. Twenty patients had progressive disease on previous regimens and six had had partial remission and then relapsed 3-34 months after previous chemotherapy. Eleven patients had previously been treated with three different regimens. 10 had been treated with two regimens, and five had been treated with one regimen. Pentostatin was administered at a dosage of 4 mg/m2 weekly for 3 weeks, then 4 mg/m2 every other week for 6 weeks and once a month for 6 months. Seven of 26 assessable patients (27%) achieved partial remission and five (19%) achieved clinical improvement. The median duration of partial remission until relapse or death was 210 days. Myelosuppression was minor and transient in responsive patients, indicating some degree of selective effect on lymphocytes. Except for one patient who died of cerebral hemorrhage during the first 6 weeks of treatment, no drug-related deaths were registered. Major toxic effects included nausea in 17 patients (mainly grade 1), infections in 15, and liver enzyme elevations in five. Thus, pentostatin is active, even in patients with advanced B-cell chronic lymphocytic leukemia that is refractory to multiple chemotherapy regimens. Response can be achieved with mild myelosuppression.

Adult↗
PubMed1990

Cimetidine induced pancytopenia. Effect on human CFU-MIX colony formation.

We describe a 26 year-old male with a pancytopenia possibly due to cimetidine. Using progenitor cell culture techniques we investigated the mechanism of this bone marrow toxicity. Our results show a cimetidine dose-dependent inhibition of normal human CFU-GM colony formation as described by Fitchen and Koeffler in 1980. No differences in growth inhibition were found between the patients' recovery marrow and the controls. Toxicity on normal human CFU-MIX colony formation was, however, far more pronounced. At concentrations as low as 5 micrograms/ml the numbers of CFU-MIX colonies were decreased by almost 20% and more than 30% in cultures of two normal bone marrow samples. A significant decrease in CFU-MIX colony size was measured even at therapeutic levels (0.5 micrograms/ml). No obvious decrease in CFU-GM colony size was noticed at low concentrations. Experiments with T-cell- and monocyte-depleted bone marrow samples gave similar results: a pronounced inhibition of the CFU-MIX colony formation at low concentrations of cimetidine whereas the CFU-GM formation was less affected. It is therefore very unlikely that Accessory cells play part in the cimetidine induced CFU-MIX inhibition. Our results suggest the existence of H2 histamine receptors on human CFU-MIX (= multipotent progenitor cell). Blocking these receptors prevents the multipotent progenitor cell from going into the DNA-synthesis phase of the cell cycle.

Adult↗
PubMed1990

Morphological evidence for a motile behavior by plasma cells.

Immunofluorescence microscopy of the adherent layer of human long-term bone marrow cultures (HLTBMCs) consistently revealed motility-associated features in a part of the plasma cells. Not only were small surface blebs observed, but also long extensions whose morphology was reminiscent of neuronal axons. The observations were made in all HLTBMCs established with normal as well as myelomatous bone marrow (BM). Plasma cells with long extensions were also noticed on May-Grünwald-Giemsa smears of original uncultured BM from normal individuals and patients with myelomatous disorders. This suggests that the motility-associated morphological features occur in vivo as well as in vitro. The observations were most striking in the one case of plasma cell leukemia, both in culture as well as in the BM smear.

Bone Marrow Cells↗
PubMed1989

DNA fingerprints revealing common and divergent human DNA methylation patterns.

We compared DNA fingerprints of different cell populations from the same individuals, after separate digestion with the isoschizomers MboI and Sau3A. Methylation differences were observed within every individual when comparing fingerprints of Sau3A- with MboI-digested DNA, and of Sau3A-digested sperm with somatic DNA. In some cases, differences were also detected between fingerprints of Sau3A-digested somatic DNA originating from various cell sources. Methylation patterns common to all cell populations examined, including the germline, were observed with a higher frequency than divergent ones. These 'common methylations' are most likely to find their origin during early embryogenesis.

DNA↗
PubMed1989

[Sulfasalazine allergy: fever, skin rash, hepatitis and T-lymphocytes].

We describe a case of severe sulfasalazine allergy. Exacerbation of the symptoms occurred after unintentional rechallenge with co-trimoxazole, indicating that the reaction was triggered by the sulphonamide component. The clinical picture consisted of generalised adenopathy, hepatitis, high fever and a maculopapular skin rash. A bone marrow biopsy and skin biopsy both showed noncaseating granulomas. The white blood cell count rose to 90.10(9)/l with 40% atypical lymphocytes (plasmacytoid). They were identified by flow cytometry as activated T lymphocytes.

Adult↗
PubMed1989

1,3'-Diethyl-4,2'-quinolylthiacyanine iodide as a "thiazole orange" analogue for nucleic acid staining.

Flow cytometric evaluation of reticulocytes has become a valuable and more precise alternative for the microscopically determined reticulocyte count. Until now, the most promising results are obtained with the "thiazole orange" (TO) nucleic acid dye. We report on the use of a "thiazole orange" analogue, 1,3'-diethyl-4,2'-quinolylthiacyanine iodide (DEQTC), which gives comparable results and is commercially available at low cost.

Benzothiazoles↗
PubMed1989

A quantitative and dynamic study of endothelial cells and megakaryocytes in human long-term bone marrow cultures.

The quantitative evolution of endothelial cells (ECs) in Dexter-type human long-term bone marrow cultures (HLTBMCs) was investigated. Using monoclonal antibodies directed against von Willebrand factor (vWF) and against membrane antigens (EN-4 and PAL-E), a low percentage--usually less than 1% of stromal cells--of ECs was detected in all confluent cultures established from 11 different bone marrow samples. Generally these cells are not associated directly with the areas of myelopoiesis ("cobblestone areas"). ECs cannot be demonstrated in the adherent layer of most young, non-confluent, and of some old, HLTBMCs. In some instances, morphological features suggestive of dynamic behavior were seen (sprouting, canal formation). In addition, a very low proportion of vWF-positive megakaryocytic cells was found in 4 of 11 cultures, always in direct contact with the stromal fibroblastic cells.

Bone Marrow↗
PubMed1989

The nature of the adherent hemopoietic cells in human long-term bone marrow cultures (HLTBMCs): presence of lymphocytes and plasma cells next to the myelomonocytic population.

An immunological analysis of the nonmacrophage hemopoietic cells in the adherent layer of human long-term bone marrow cultures was performed in situ. It revealed not only the expected granulocytic and monocytic cells, but an important lymphoid population as well. The latter consisted of cells bearing the markers of mature T lymphocytes, B lymphocytes, and plasma cells. These cells were also present in the hemopoietic foci of the adherent layer, the so-called cobblestone areas. Although more CD8+ than CD4+ lymphocytes were generally present in the initial bone marrow inoculum, both the adherent layer and the nonadherent fraction disclosed a preponderance of CD4+ cells after a short period of culture. The majority of the lymphoid cells were present in the adherent layer, rather than in the nonadherent fraction of the cultures. The long-term presence of lymphoid elements in the adherent layer suggests their affinity for the bone marrow stroma and the possible enhancement of their persistence in vitro by contact with these cells.

Antibodies, Monoclonal↗
PubMed1989

Human long-term bone marrow cultures (HLTBMCs) in myelomatous disorders.

Human long-term bone marrow cultures (HLTBMCs) were established with bone marrow (BM) collected from five patients with myelomatous disorders (four with multiple myeloma, one with plasma cell leukemia). In all cases, up to at least 6 weeks of culture, there was a persistence of the monoclonal plasma cell population in the adherent layer of the culture. In some cultures proliferating plasma cells could be demonstrated by the Ki-67 monoclonal antibody. In all instances a paraprotein could be shown in the conditioned medium. This study demonstrates that malignant plasma cells, in analogy to their normal counterparts, have an affinity for the BM stroma and suggests that their long-term survival might be enhanced by their interaction with it.

Bone Marrow↗
PubMed1989

Comparison of human long-term bone marrow cultures (HLTBMCs) established from fresh and post-cryopreservation bone marrow samples from living and cadaver donors.

Human long-term bone marrow cultures (HLTBMCs) were established from thawed post-cryopreservation, as well as from cadaver donor bone marrow (BM) samples. The longevity was similar in the different series of HLTBMCs examined. CFU-GM could be cultured out of cadaver donor BM. This indicates that previously healthy people, under the conditions generally accepted as suitable for organ donation, could become suitable donors for allogeneic BM transplantation.

Bone Marrow Cells↗
PubMed1988

Assessment of anti-HLA antibodies in sera being tested for platelet reactivity by a platelet lymphocyte immunofluorescence test (PLIFT).

An indirect immunofluorescence test using a platelet mononuclear cell suspension is described. The test is a simple and sensitive method to assess the contamination by anti-HLA antibodies of sera being tested for platelet reactivity and eliminates the need to support two independent test systems such as lymphocytotoxicity and immunofluorescence testing. The test could be of value in routine platelet serology testing and platelet crossmatching.

Antigen-Antibody Reactions↗
PubMed1988

Karyotypic evidence for the leukemic involvement of the erythroblasts in erythroleukemia.

With the use of a monoclonal anti-glycophorin A antibody and flow cytometric cell sorting, an erythroleukemic bone marrow sample was separated in highly purified erythroblast and myeloblast fractions. Similar karyotypic anomalies were found in both cell populations as in the unseparated bone marrow. This study confirms that acute nonlymphocytic leukemia can originate at the level of a multipotential hemopoietic stem cell.

Antibodies, Monoclonal↗
PubMed1987

Flow cytometric analysis of T-lymphocyte subpopulations in B-cell chronic lymphocytic leukemia: correlation with clinical stage.

Several authors have studied the T-lymphocyte subpopulations in B-cell chronic lymphocytic leukemia (B-CLL), but previous studies were performed after preceding enrichment procedures, which are known to cause selective losses of certain subpopulations. To correct for this deficiency we used flow cytometric analysis, which enabled us to measure subpopulations directly on total blood samples. We studied T-lymphocyte subsets with OKT monoclonal antibodies in 45 patients with B-CLL. Serum levels of IgG, IgA and IgM were assayed simultaneously and findings were correlated with clinical stage (Rai classification). The absolute number of CD4-positive cells decreased in more advanced Rai stages, while the absolute number of CD8-positive cells increased, resulting in a progressive reduction in CD4/8 ratio. Results from patients in stages with equal prognosis (Rai I and II, Rai III and IV) were similar and when these results were grouped the observed differences were highly significant and clearly correlated with all prognostic groups.

Adult↗