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Biomedical subjects

H G Drexler

Publications and source records attributed to H G Drexler.

At least 163 records · Page 9Linked to original sources
PubMed1993

Terminal deoxynucleotidyl transferase (TdT) expression in acute myeloid leukemia.

Terminal deoxynucleotidyl transferase (TdT) was initially considered as a marker of immature lymphoid cells, but many studies have since provided conclusive evidence for the existence of TdT+ cases of acute myeloid leukemia (AML). The reported incidence of TdT+ AML cases varies largely (from 0% to 55%, average of combined data of the literature 18%, children 19%, and adults 21%) suggesting interlaboratory differences in the types of AML examined, the sensitivity of the method used, and the percentage of positive blasts taken as cut-off value. Significantly higher frequencies of TdT+ AML were reported in studies employing immunocytochemical staining (alkaline phosphatase anti-alkaline phosphatase or immunoperoxidase) than in series using immunofluorescence microscopy or biochemical assays. Statistical analysis of various cut-off levels demonstrates an inverse correlation between cut-off point and incidence. The combined data show that TdT-positivity is more common in the immature cell types (M0, M1), with no correlation with age or sex. Except for contested suggestions of an association with t(6;9) and t(8;21), no clear relationship between karyotype and TdT status has been documented. Although an association between T-cell receptor or immunoglobulin gene rearrangements and expression of TdT in AML was postulated, subsequent studies could not demonstrate this correlation. There was no significant relationship with other immunophenotypic markers except for CD34 positivity suggesting that the TdT+ cells represent an immature population. The percentage of positive cells was usually lower in AML than in ALL; in most cases only a subpopulation of the AML cells was TdT+. Thus, TdT could be viewed as a marker of hematopoietic immaturity. In about one-half of the studies on adults, TdT expression was reported to indicate a poor prognosis; others did not find any prognostic difference between TdT+ and TdT- AML cases. No correlation between TdT-positivity and prognosis was found in childhood AML.

Adult↗
PubMed1993

Modulation of gene expression in the acute promyelocytic leukemia cell line NB4.

The human leukemic cell line NB4 was derived from a patient with acute promyelocytic leukemia and is characterized by a specific 15;17 chromosomal translocation. We analyzed the response of NB4 and HL-60 cells to the biomodulators all-transretinoic acid (ATRA), vitamin D3 (Vit D3) and the protein kinase C agonists bryostatin 1 (Bryo 1) and phorbol ester 12-O-tetradecanoylphorbol 13-acetate (TPA). HL-60 cells were used for comparison being arrested at the myeloblastic-promyelocytic stage, but lacking the t(15;17) abnormality. In most experiments Vit D3 was only weakly or not at all effective. The other three reagents effectively slowed or stopped the proliferation of the cells in suspension. Associated with this proliferation arrest was the cell differentiation along the myeloid cell lineages: ATRA modulated morphological features indicative of granulocytic differentiation; Bryo 1 and TPA caused also distinct morphological changes. The inducers up-regulated the expression of CD11b (without changing the surface expression of other markers, e.g. CD13, CD14, CD15, CD33, CD68, HLA-DR) and completely down-regulated the originally strong expression of myeloperoxidase and c-myc at the mRNA level. Thus, ATRA- or protein kinase C activator-induced differentiation involved changes associated with maturational processes. Induction of terminal differentiation of leukemic cells by physiological or pharmacological modulators may be able to control the growth of the malignant cells and has therapeutic implications.

Antigens, CD↗
PubMed1993

Possible new genetic marker for human lymphoid leukemias as detected by ribosomal protein S14 cDNA.

Two polymorphic restriction fragments (bands) were detected in human lymphoid leukemias using restriction enzyme HindIII and a DNA probe coding for the human ribosomal protein S14 gene. Seventy-four leukemia samples of either fresh or cultured cells (54 lymphoid and 20 non-lymphoid) and 28 normal leukocyte samples as controls were examined. Southern blot analysis of their genomic DNA showed that, in addition to seven distinct and invariant bands, two new bands of 3.0 kb and 1.8 kb were detected in 19 of 20 cases (95%) of T-cell leukemias and in 20 of 34 cases (59%) of B-cell and B-precursor-cell leukemias tested. These two new bands were not detected, however, in any of the 20 cases of myeloid leukemias, nor in any of the 28 cases of normal control samples. A fragment of approximately 400 bp sequences can be enzymatically amplified from the 3.0 kb and 1.8 kb size-selected genomic DNA by polymerase chain reaction. A processed pseudogene seems to be involved, as judged by the size of the amplified product. These results suggest this could be a genetic marker for lymphoid leukemias and may provide new insight into the heterogeneity of the genetic changes taking place in human hematopoietic malignancies.

Adolescent↗
PubMed1993

MDR1 expression in human leukemia-lymphoma cell lines.

We examined the expression of the mdr1 gene in 90 human tumor cell lines of which 79 were derived from leukemia or lymphoma samples. Using Northern blot analysis and the mdr1.1 probe, only three cell lines, KB-V1 (a positive control), EM-2, A-704, displayed mdr1 mRNA expression. Immunocytochemical APAAP staining of these three and 15 other cell lines with the anti-p170 glycoprotein monoclonal antibody JSB-1 was negative in all but the KB-V1 cells. In contrast to the results seen in freshly explanted neoplastic cells, the mdr1 gene does not seem to be functionally expressed in the majority of unmanipulated and unselected, continuous human tumor cell lines.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1993

Transcription and protein expression of mb-1 and B29 genes in human hematopoietic malignancies and cell lines.

The transmembrane forms of all immunoglobulin (Ig) classes are associated with two glycoproteins, mb-1 and B29, that are crucial for signal transduction following antigen binding to the Ig molecule. We have investigated the transcription and protein expression of mb-1 and B29 genes during B-cell development. Sixty human continuous cell lines (35 B-lineage, 11 T-lineage, 11 myeloid-lineage and three non-hematopoietic) and 75 hematopoietic malignancies (55 B-lineage, 12 T-lineage and eight myeloid-lineage), were tested for RNA expression by Northern blotting experiments with the mb-1 pRA3 cDNA probe, and a newly isolated B29 cDNA probe. Protein expression was analyzed by immunofluorescence microscopy of cytocentrifuge preparations, which were labeled with the anti-mb-1 HM57 monoclonal antibody (mAb) and an anti-B29 polyclonal antiserum, directed against intracellular epitopes of these polypeptides. Except for two early precursor B-cell lines, mb-1 and B29 transcripts and proteins were detected in all B-cell lines and B-cell malignancies, i.e. from immature to more mature B cells, irrespective of their Ig class expression. Transcription of mb-1 genes seems to be down-regulated at the plasma cell stage, because no mb-1 transcripts and mb-1 proteins could be detected in the four plasma cell lines and two plasma cell leukemias tested. B29 transcripts were detectable in these cell samples, but low levels of B29 proteins were only detected in one plasma cell line. The HM57 mAb gave strong labeling on fresh cytocentrifuge preparations of all B-cell samples, and this mb-1 protein expression appeared to be B-cell specific. We therefore conclude that the HM57 mAb is well suited for the detection of the mb-1 molecule as a pan-B-cell marker for the diagnosis of immature and mature B-cell malignancies. The expression pattern of the mb-1 protein is comparable to that of the CD19 and CD22 antigens, but has the advantage of being B-lineage specific. Although B29 protein expression was restricted to B-lineage cells, the anti-B29 antiserum is less suitable for diagnosis of B-cell malignancies, because of the variable and generally weak signals on cytocentrifuge preparations.

Antigens, CD↗
PubMed1993

Expression of the monocyte-specific esterase gene in leukemia-lymphoma cell lines.

The expression of the monocyte esterase was examined in a panel of 77 continuous human leukemia-lymphoma cell lines representing all hematopoietic cell lineages and in 16 other cell lines. Accumulation of mRNA, determined by Northern blotting with the cDNA probe HMSE-1, and production of the protein, shown by isoelectric focusing on polyacrylamide gels, correlated with differentiation of the cells along the monocytic lineage. None of the lymphoid, erythroid, megakaryoblastic or Hodgkin's disease derived cell lines or the non-hematopoietic human tumor cell lines expressed the full-length mRNA of 2.0 kb. These results support the notion that this enzyme, a serine hydrolase with still unknown physiological functions, is specifically expressed in cells committed to the monocyte/macrophage cell lineage.

Animals↗
PubMed1992

Role of IL-6, IL-2, and IL-4 in the in vitro induction of cytotoxic T cells.

The mode of IL-6-induced differentiation of Con A-stimulated CD4-CD8+ CTL-P was examined. Through application of neutralizing anti-IL-6, anti-IL-2, and anti-IL-4 mAb it was shown that IL-6 is an "early acting" factor for development of accessory cell-depleted thymocytes. IL-2 and IL-4 are obligatory "late acting" factors for this process. In accordance IL-4, but not IL-6, induced active CTL from CD4-CD8+ CTL-P. The increase of CD4-CD8+ CTL originates at least partially from CD4+CD8+ cells differentiating to active CTL in vitro. CTL development was paralleled by an increase in CD4-CD8+ cells and by a distinct increase in [3H]TdR uptake on day 2 of cultivation. Our data suggest that IL-6 induces Th cells to produce IL-2 and IL-4, the mediators for final differentiation of CD4-CD8+ cells.

Animals↗
PubMed1992

Expression of cytokine genes, cytokine receptor genes, and transcription factors in cultured Hodgkin and Reed-Sternberg cells.

In the present study, we show by Northern blot analysis and enzyme linked immunosorbent assay that the Hodgkin's disease (HD)-derived cell lines HDLM-2 and KM-H2 express a variety of cytokine genes either constitutively or upon induction with phorbol ester 12-O-tetradecanoylphorbol-13-acetate. Cytokine genes expressed by HD-derived lines include granulocyte-macrophage colony-stimulating factor (CSF), macrophage-CSF, interleukin (IL)-1-alpha, IL-3, IL-5, IL-6, IL-8, leukemia inhibitory factor, tumor necrosis factor-alpha, tumor necrosis factor-beta, and transforming growth factor-beta, while transcripts and the corresponding proteins for granulocyte-CSF, IL-1-beta, IL-2, IL-4, IL-7, IL-10, and the JE/macrophage chemoattractant and activating factor gene were not detectable in cytoplasmic RNA and culture supernatants obtained from both lines. In addition, IL-2 receptor (R) p55 and macrophage-CSF R (c-fms) genes were expressed by both lines. HDLM-2, but not KM-H2 cells, exhibited the IL-6 R p80 and the IL-2 R p75 chain. Analysis of nuclear proteins that bind to oligonucleotides containing the consensus sequences of the transcription factors activation protein 1, nuclear factor (NF) kappa B, and NFAT 1 revealed a pattern for HD lines resembling that of activated T-cells: HDLM-2 and KM-H2 cells constitutively expressed NF binding to the NF of activated T-cells (type 1), previously described to be T-cell specific. In addition, NF kappa B-binding proteins obtained from both lines showed, in electrophoretic mobility shift assays, the same migration pattern as T-cell-derived proteins but differed from monocyte- and B-cell-derived proteins. UV cross-linking experiments confirmed that NF kappa B-binding proteins of M(r) 85,000, 75,000, and 50,000/55,000 were detectable in nuclear extracts obtained from T-cells and both HD lines, while monocytes and B-cells displayed the M(r) 50,000/55,000 and 75,000 NF kappa B complex only. Both HD lines also constitutively expressed transcripts for c-fos and c-jun, which are involved in heterodimeric formation of the transcription factor activation protein 1, as well as for the NF kappa B/KBF1 gene.

Antigens, CD↗
PubMed1992

Mycoplasma contamination in human leukemia cell lines. I. Comparison of various detection methods.

The sensitivity and reliability of seven assays for mycoplasma detection were tested on a panel of leukemia cell lines. The assays used were: microbiological cultivation on broth and agar, immunofluorescent visualization of mycoplasmal DNA using DAPI (both direct staining and after multiplication of the contaminants on an indicator cell line), a nucleic acid hybridization assay with a radioactive probe specific for mycoplasmal rRNA, and ELISA with mycoplasma-specific polyclonal antibodies, a biochemical method utilizing 6-MPDR, and a mycoplasma-specific monoclonal antibody in immunofluorescence staining. The broth-agar method, the two DAPI tests and the RNA hybridization assay produced the highest detection rates; a number of false-negative cases were recorded by the other tests. The detection rates, costs, requirement for specialized equipment and other characteristics were evaluated for each method. Since each technique also has disadvantages and certain limitations and since no method can be regarded as the 'gold standard', at least two procedures should be used in routine screening for mycoplasma in cell cultures.

Antibodies, Monoclonal↗
PubMed1992

Mycoplasma contamination in human leukemia cell lines. II. Elimination with various antibiotics.

19 suspension cell lines were treated with antibiotics for elimination of chronic contamination with mycoplasma. We compared the efficiency, cytotoxicity and cross-resistance of the commercially available antibiotics MRA (Mycoplasma Removal Agent, a quinolone derivative and DNA gyrase inhibitor), Ciprobay (ciprofloxacin, also a quinolone derivative and DNA gyrase inhibitor), and BM-cyclin (a combination of tiamulin, a pleuromutilin derivative, and minocycline, a tetracycline derivative, both inhibitors of protein synthesis on ribosomes). Contaminants were eliminated in all 19 cell lines by BM-Cyclin. Only 74% of the cell lines were cleared of contamination by both MRA and Ciprobay. Successful treatment was monitored by three mycoplasma detection assays. Cross-resistance was noted between MRA and Ciprobay in four of the five cell lines not cleared by either reagent. This resistance could, however, be overcome by consecutive exposure to BM-cyclin. Employed at the recommended concentrations, the antibiotics did not cause marked cytotoxicity, but the growth of the cells was affected to various degrees by some antibiotics. The elimination of mycoplasma from chronically contaminated cell lines is an effective alternative to other treatment protocols, but is cost-intensive and time-consuming; lasting damaging effects of the treatments on the eukaryotic cells cannot be excluded. Long-term post-treatment monitoring is mandatory, since contaminants may only be suppressed and then recur.

Anti-Bacterial Agents↗
PubMed1992

Interleukin 9 is expressed by primary and cultured Hodgkin and Reed-Sternberg cells.

We show by mRNA hybridization analysis and immunostaining using a mouse monoclonal antibody (moAb) to recombinant human interleukin 9 (IL-9) that both primary and cultured Hodgkin and Reed-Sternberg (H-RS) cells produce IL-9 transcripts and protein and express surface binding sites for IL-9. In addition, the growth of H-RS cells obtained from the HDLM-2 line (abundantly producing IL-9 transcripts) was significantly inhibited when anti-IL-9 moAb or an IL-9 antisense oligodeoxyribonucleotide was added to cultures. Excess addition of recombinant human IL-9 relieved the effects of anti-IL-9 moAb on HDLM-2 growth. Growth of H-RS cells of the KM-H2 line, which displays only low amounts of IL-9 detectable upon hybridization of polyadenylic acid-selected RNA only, was not affected by anti-IL-9 moAb. The proliferative capacity of KM-H2 cells in soft agar and liquid suspension cultures was, however, augmented at least 3-fold when cells were exposed to recombinant human IL-9. In conclusion, our results show that IL-9 is expressed by H-RS cells and point to a possible role of this molecule as a growth factor for these cells.

Antibodies, Monoclonal↗
PubMed1992

Treatment of mycoplasma-contaminated continuous cell lines with mycoplasma removal agent (MRA).

Thirty-nine continuous adherent or suspension cell lines were treated with a quinolone antibiotic, Mycoplasma Removal Agent (MRA), for the elimination of chronic mycoplasma contamination. In preliminary experiments MRA did not show any cytostatic or cytotoxic effects on mycoplasma-free cell cultures in concentrations up to ten-fold the concentration used for mycoplasma eradication. Twenty-eight cell lines (72%) were effectively cleansed of the mycoplasma contaminants by MRA treatment. The persistent removal of the mycoplasma infection was monitored by three mycoplasma detection assays. In seven cell lines (18%) the mycoplasmas were resistant to treatment with MRA. The resistant species was mainly M. arginini followed by M. orale and A. laidlawii; however, other cell lines harboring these species were cured. Four cell lines (10%) which prior to treatment presented with decreased viability and poor or no cell growth were lost during or shortly after the exposure to the antibiotic. If an antibiotic elimination is attempted it is imperative to closely examine the effectiveness of treatment and possible eukaryotic cytotoxicity. The treated mycoplasma-free cells may also no longer express the original features as a result of treatment or the absence of mycoplasma.

Cell Survival↗
PubMed1992

Recent results on the biology of Hodgkin and Reed-Sternberg cells. I. Biopsy material.

The most recent sophisticated investigations have provided new and revealing, but also contradictory and controversial information on the biological nature and the cellular origin of Hodgkin and Reed-Sternberg cells (H-RS). Immunophenotypic analyses have shown variable phenotypic antigen expression; but, on balance the data suggest a lymphoid cell expressing T- and/or B-cell-associated markers and certain activation antigens while lacking immunological features of monocytes-macrophages or other lineages. Molecular genetic studies have demonstrated heterogenous findings with respect to rearrangements of T-cell receptor and immunoglobulin genes. Only a small percentage of the cases has rearrangements; this might be due to the threshold of sensitivity of the method combined with the scarcity of the malignant cells. Epstein-Barr virus (EBV) genomes are clonally integrated in the H-RS cells of about half the cases. The significance of these findings--whether EBV is a causative agent or an epiphenomenon--remains to be elucidated. H-RS cells express mRNA and proteins of various cytokines and cytokine receptors implying a predominant role for cytokines in the pathophysiology of HD. The mononuclear and polynuclear H-RS cells are capable of DNA synthesis and nuclear division; the lack of cellular division leads to multinuclearity through the process of endomitosis. Mutations and expression of only a limited number of oncogenes have been tested thus far. Whether the bcl-2 oncogene is involved in HD remains a matter of debate. Aneuploidy and non-random chromosomal abnormalities are the results of cytogenetic analyses of H-RS cells. However, no chromosomal marker specific for HD has yet been found. Thus, while studies of EBV involvement, growth factor production, oncogene expression and chromosomal abnormalities contributed a fair amount of new data on the nature of H-RS cells, only immunophenotyping and genotyping provided some indication of the cellular derivation: an activated lymphoid cell that possibly expresses oncogenes, that probably is infected with EBV, that most likely produces cytokines, that certainly has multiple karyotypic abnormalities.

Antigens, Surface↗
PubMed1992

Dolastatin 10 and dolastatin 15: effects of two natural peptides on growth and differentiation of leukemia cells.

The effects of two natural peptides, dolastatin 10 and dolastatin 15, on growth and differentiation of hematopoietic cells were studied using freshly explanted leukemia cells and continuous leukemia cell lines. The proliferation of several myeloid cell lines and of growth-factor-stimulated peripheral blood cells from patients with acute myeloid leukemia (AML) was efficiently inhibited by the two agents at concentrations between 1 and 0.01 nM. Growth inhibition was dose-dependent and reversible. Neither of the dolastatins exhibited significant cytotoxicity on dividing cells, nor did they interfere with the viability of resting cells. The 12-O-tetradecanoylphorbol 13-acetate or bryostatin I induced differentiation of AML cells was not affected by the dolastatins. Short-term exposure to the phorbol ester conferred reduced sensitivity of the cell line HL-60 to the antiproliferative effect of the drugs. Our data suggest that the dolastatins alone or in combination with other drugs could exert a role in the treatment of human myeloid leukemia.

Antineoplastic Agents↗
PubMed1992

Hodgkin's disease derived cell lines: a review.

A number of so-called "HD cell lines" have been established over the last 10-15 years (Table 1). Or those 15 cell lines we studied, only the cell lines CO, DEV, HD-70, HDLM, KM-H2, L-428, L-540 and SUP-HD1 can be regarded to represent true HD cell lines. According to the immunostaining results and molecular genetic data, these 8 cell lines can be assigned either to the T-cell lineage (CO, HDLM, L-540) or B-cell lineage (DEV, HD-70, KM-H2, SUP-HD1). With the data currently available, the cell lineage origin of L-428 cannot be unequivocally determined, but appears to be lymphoid. All but one of these eight HD cell lines have been established from patients with the nodular sclerosis subtype. Therefore, the conclusions drawn from the in vitro studies are limited to this histological subtype of HD. It is conceivable that culture conditions select for a particular type of cell that will survive. The state of differentiation of these HD cell lines remains unclear due to the incomplete expression of T- or B-cell antigens. The in vitro cells and the in vivo H-RS cells share, however, the expression of the unique activation markers CD15, CD25, CD30, CD71 and HLA-DR. Recently published data indicate that the HD cell lines express and produce a large number of cytokines. Multiple non-random chromosomal abnormalities and the expression of various proto-oncogenes are also new and exciting findings and certainly deserve further study. In summary, although the cultured cells are not unequivocally proven to be the direct progeny of in vivo H-RS cells, several continuous HD cell lines have been established that display a variety of phenotypical features identical or similar to those of their presumed in vivo counterparts. Surface marker, molecular genetic and other features suggest a T- or B-cell derivation. An extrapolation of these conclusions would point to a lymphoid origin of H-RS cells. Whether H-RS cells can originate from other cell types such as monocytes/macrophages or reticulum cells, cannot be answered with the currently available HD cell lines.

Adolescent↗
PubMed1992

Differences in DNA fingerprints of continuous leukemia-lymphoma cell lines from different sources.

The genetic stability of human cell lines in long-term culture has been tested by DNA fingerprinting a panel of 31 different continuous cell lines from patients with leukemias or lymphomas. Duplicates of the same cell line obtained from different sources, subclones of cell lines, and samples of cell lines at different passage levels were studied. In most cases the fingerprints of duplicates of the same cell line remained perfectly preserved even after long-time passaging. However, in five cases there were notable differences between individual fragments of corresponding fingerprints. We have found four cases of mislabeled and/or cross-contaminated cell lines so far. Taken together, our results indicate that DNA fingerprinting qualifies as a very reliable means of cell line identification which allows the detection of mislabelling or contamination and of genetic variation among subclones.

Base Sequence↗