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W Terpstra

Publications and source records attributed to W Terpstra.

At least 19 recordsLinked to original sources
PubMed2002

Assembly of fingerprint contigs: parallelized FPC.

SUMMARY: One of the more common uses of the program FingerPrint Contigs (FPC) is to assemble random restriction digest 'fingerprints' of overlapping genomic clones into contigs. To improve the rate of assembling contigs from large fingerprint databases we have adapted FPC so that it can be run in parallel on multiple processors and servers. The current version of 'parallelized FPC' has been used in our laboratory to assemble mammalian BAC fingerprint databases, each containing more than 300000 BAC fingerprints. AVAILABILITY: This parallelized version of FPC is available under the GNU GPL licence, and can be downloaded from ftp://ftp.bcgsc.bc.ca/pub/fpcd.

Algorithms↗
PubMed1999

Multilineage outgrowth of both malignant and normal hemopoietic progenitor cells from individual chronic myeloid leukemia patients in immunodeficient mice.

In this study the ability of malignant and normal progenitors in peripheral blood (PB) and bone marrow (BM) of CML patients in chronic phase to proliferate and produce mature progeny after transplantation into hereditary immunodeficient (SCID and NOD/SCID) mice was examined. Engraftment in NOD/SCID mice preconditioned by total body irradiation (TBI) alone was 10-fold higher than in SCID mice preconditioned by macrophage depletion and TBI, demonstrating that NOD/SCID mice are more suitable for engraftment of chronic phase CML cells. Low-density cells at cell doses of 10-30 x 10(6) and purified CD34+ cells at doses of approximately 0.2 x 10(6) engrafted NOD/SCID mice, with levels of 2 to 20% CD45+ cells with production of monocytes, granulocytes, erythroid cells, B-lymphocytes, CD34+ cells and variable frequencies of erythroid and myeloid colony-forming cells. As demonstrated by fluorescent in situ hybridization (FISH) analysis, purified human myeloid, B-lymphoid, erythroid and CD34+ cells from chimeric mouse BM contained Philadelphia-chromosome (Ph)-positive cells and Ph- cells in similar frequencies as primary cells from the CML patients. These results demonstrate that production of mature normal as well as malignant cells of multiple lineages were supported with similar efficiency. In contrast, all human erythroid and myeloid clonogenic cells detected in the mice were Ph-, which can be attributed to less efficient maintenance or more rapid differentiation of immature Ph+ cells in the mouse microenvironment. CML blast crisis cells also grew well in NOD/SCID mice, with 80-90% of human cells produced containing the Ph- chromosome. The availability of an in vivo assay that supports outgrowth of normal and malignant stem cells from chronic phase and blast crisis CML patients will facilitate examination of differential effects of growth factors, inhibitory cytokines and cytotoxic drugs on survival of normal and malignant stem cells in vivo and on progression of chronic phase CML towards blast crisis.

Animals↗
PubMed1998

Transplantation of human umbilical cord blood cells in macrophage-depleted SCID mice: evidence for accessory cell involvement in expansion of immature CD34+CD38- cells.

In vivo expansion and multilineage outgrowth of human immature hematopoietic cell subsets from umbilical cord blood (UCB) were studied by transplantation into hereditary immunodeficient (SCID) mice. The mice were preconditioned with Cl2MDP-liposomes to deplete macrophages and 3.5 Gy total body irradiation (TBI). As measured by immunophenotyping, this procedure resulted in high levels of human CD45(+) cells in SCID mouse bone marrow (BM) 5 weeks after transplantation, similar to the levels of human cells observed in NOD/SCID mice preconditioned with TBI. Grafts containing approximately 10(7) unfractionated cells, approximately 10(5) purified CD34+ cells, or 5 x 10(3) purified CD34+CD38- cells yielded equivalent numbers of human CD45+ cells in the SCID mouse BM, which contained human CD34+ cells, monocytes, granulocytes, erythroid cells, and B lymphocytes at different stages of maturation. Low numbers of human GpA+ erythroid cells and CD41+ platelets were observed in the peripheral blood of engrafted mice. CD34+CD38+ cells (5 x 10(4)/mouse) failed to engraft, whereas CD34- cells (10(7)/mouse) displayed only low levels of chimerism, mainly due to mature T lymphocytes. Transplantation of graded numbers of UCB cells resulted in a proportional increase of the percentages of CD45+ and CD34+ cells produced in SCID mouse BM. In contrast, the number of immature, CD34+CD38- cells produced in vivo showed a second-order relation to CD34+ graft size, and mice engrafted with purified CD34+CD38- grafts produced 10-fold fewer CD34+ cells without detectable CD34+CD38- cells than mice transplanted with equivalent numbers of unfractionated or purified CD34+ cells. These results indicate that SCID repopulating CD34+CD38- cells require CD34+CD38+ accessory cell support for survival and expansion of immature cells, but not for production of mature multilineage progeny in SCID mouse BM. These accessory cells are present in the purified, nonrepopulating CD34+CD38+ subset as was directly proven by the ability of this fraction to restore the maintenance and expansion of immature CD34+CD38- cells in vivo when cotransplanted with purified CD34+CD38- grafts. The possibility to distinguish between maintenance and outgrowth of immature repopulating cells in SCID mice will facilitate further studies on the regulatory functions of accessory cells, growth factors, and other stimuli. Such information will be essential to design efficient stem cell expansion procedures for clinical use.

ADP-ribosyl Cyclase↗
PubMed1998

Maturation hierarchy of leukemic stem cells.

Here we discuss the characteristics of various progenitor cell assays for human acute myeloid leukemia (AML) with emphasis on the repopulating properties of human AML progenitor cells, their potential relevance for pathophysiological studies, and treatment development in AML.

Colony-Forming Units Assay↗
PubMed1998

Phenotype variability of the dominant beta-thalassemia induced in four Dutch families by the rare cd121 (G-->T) mutation.

Eight patients who were carriers of beta-thalassemia induced by the cd121 (G-->T) mutation are described in four nonrelated Dutch families. This mutant, which is considered rare and inherited in a dominant manner, is expressed in a different way among each of the four families and even among carriers of the same family. The symptoms vary from an hemolytic anemia of intermediate gravity with hepatosplenomegaly, inclusion bodies and erythroblastosis, to a mild anemia with minor hematological abnormalities. We report the analytical procedures used for the detection of the mutant, the hematological and clinical data of the four families and discuss the variable physiopathology of this molecular defect. We also compare the variation in fetal hemoglobin expression in relation to the haplotypes of the beta-gene cluster and to the different hematological conditions. The presence of this rare mutant in four nonrelated Dutch families could derive from a single mutation or from multiple events. The existence of the four mutations in three different haplotypes suggests the occurrence of at least two independent events. The presence of five abnormal hemoglobins and the beta-thalassemia defect on different haplotypes at cd121 also suggests a relatively increased rate of mutations at this particular site.

Adult↗
PubMed1998

GM-CSF receptor targeted treatment of primary AML in SCID mice using Diphtheria toxin fused to huGM-CSF.

The severe combined immunodeficient (SCID) mouse model may be used to evaluate new approaches for the treatment of acute myeloid leukemia (AML). We have previously demonstrated the killing of SCID mouse leukemia initiating cells by in vitro incubation with human GM-CSF fused to Diphtheria toxin (DT-huGM-CSF). In this report, we show that in vivo treatment with DT-huGM-CSF eliminates AML growth in SCID mice. Seven cases of AML were studied. SCID mice were treated intraperitoneally with the maximally tolerated dose of 75 microg/kg/day for 7 days. Antileukemic efficacy was determined at days 40 and 80 after transplantation, by enumerating the percentages of human cells in SCID bone marrow using flow cytometry and short tandem repeat polymerase chain reaction (STR-PCR) analysis. Four out of seven AML cases were sensitive to in vivo treatment with DT-huGM-CSF at both evaluation time points. In three of these cases, elimination of human cells was demonstrated by flow cytometry and STR-PCR. One AML case showed moderate sensitivity for DT-huGM-CSF, and growth of the two remaining AML cases was not influenced by DT-huGM-CSF. Sensitivity was correlated with GM-CSFR expression. Our data show that DT-huGM-CSF can be used in vivo to reduce growth of AML and warrant further development of DT-huGM-CSF for the treatment of human AML.

Animals↗
PubMed1997

Diphtheria toxin fused to granulocyte-macrophage colony-stimulating factor eliminates acute myeloid leukemia cells with the potential to initiate leukemia in immunodeficient mice, but spares normal hemopoietic stem cells.

We studied the cell kill induced by granulocyte-macrophage colony-stimulating factor (GM-CSF ) fused to Diphtheria Toxin (DT-GM-CSF ) in acute myeloid leukemia (AML) samples and in populations of normal primitive hemopoietic progenitor cells. AML samples from three patients were incubated in vitro with 100 ng/mL DT-GM-CSF for 48 hours, and AML cell kill was determined in a proliferation assay, a clonogenic assay colony-forming unit-AML (CFU-AML) and a quantitative long-term bone marrow (BM) culture ie, the leukemic-cobblestone area forming cell assay (L-CAFC). To measure an effect on cells with in vivo leukemia initiating potential DT-GM-CSF exposed AML cells were transplanted into immunodeficient mice. In two out of three samples it was shown that all AML subsets, including those with long-term abilities in vivo (severe combined immunodeficient mice) and in vitro (L-CAFC assay) were reduced in number by DT-GM-CSF. Cell kill induced by DT-GM-CSF could be prevented by coincubation with an excess of GM-CSF, demonstrating that sensitivity to DT-GM-CSF is specifically mediated by the GM-CSF receptor. Therefore, binding and internalization of GM-CSF probably occur in immature AML precursors of these two cases of AML. The third AML sample was not responsive to either GM-CSF or DT-GM-CSF. The number of committed progenitors of normal bone marrow (burst-forming unit-erythroid, colony-forming unit granulocyte- macrophage, and cobble stone area forming cell [CAFC] week 2) and also the number of cells with long-term repopulating ability, assayed as week 6 CAFC, were unchanged after exposure to DT-GM-CSF (100 ng/mL, 48 hours). These studies show that DT-GM-CSF may be used to eliminate myeloid leukemic cells with long-term potential in vitro and in immunodeficient mice, whereas normal hemopoietic stem cells are spared.

Acute Disease↗
PubMed1997

Application of myeloid growth factors in the treatment of acute myeloid leukemia.

The current interest in the clinical use of the hematopoietic growth factors (HGF) in the treatment of patients with acute myeloid leukemia (AML) relates to the promise of reducing morbidity and improving survival through mitigating the complications of cytotoxic therapy. Another possible mode of employment of HGFs is derived from the ability of these peptides to directly stimulate leukemic cells and potentially enhance the efficacy of antileukemic therapy. Here we discuss the experimental basis and the rationale of the application of HGFs in AML and review the accumulating results from clinical studies.

Acute Disease↗
PubMed1997

Facilitated engraftment of human hematopoietic cells in severe combined immunodeficient mice following a single injection of Cl2MDP liposomes.

Transplantation of normal and malignant human hematopoietic cells into severe combined immunodeficient (SCID) mice allows for evaluation of long-term growth abilities of these cells and provides a preclinical model for therapeutic interventions. However, large numbers of cells are required for successful engraftment in preirradiated mice due to residual graft resistance, that may be mediated by cells from the mononuclear phagocytic system. Intravenous (i.v.) injection of liposomes containing dichloromethylene diphosphonate (Cl2MDP) may eliminate mouse macrophages in spleen and liver. In this study outgrowth of acute myeloid leukemia (AML) cells and umbilical cord blood (UCB) cells in SCID mice conditioned with a single i.v. injection of Cl2MDP liposomes in addition to sublethal total body irradiation (TBI) was compared to outgrowth of these cells in SCID mice that had received TBI alone. A two- to 10-fold increase in outgrowth of AML cells was observed in four cases of AML. Administration of 10(7) UCB cells reproducibly engrafted SCID mice that had been conditioned with Cl2MDP liposomes and TBI, whereas human cells were not detected in mice conditioned with TBI alone. As few as 2 x 10(4) purified CD34+ UCB cells engrafted in all mice treated with Cl2MDP liposomes. In SCID mice treated with macrophage depletion unexpected graft failures were not observed. Histological examination of the spleen showed that TBI and Cl2MDP liposomes i.v. resulted in a transient elimination of all macrophage subsets in the spleen, whereas TBI had a minor effect. Cl2MDP liposomes were easy to use and their application was not associated with appreciable side-effects. Cl2MDP liposome pretreatment in combination with TBI allows for reproducible outgrowth of high numbers of human hematopoietic cells in SCID mice.

Animals↗
PubMed1997

Atypical HbH disease in a Surinamese patient resulting from a combination of the -SEA and -alpha 3.7 deletions with HbC heterozygosity.

The first case of haemoglobin H (HbH) disease in combination with haemoglobin C (HbC) is reported in a man of Surinamese origin. Only haemoglobin A (HbA) and HbC were detected by electrophoresis. The amount of HbC was much less than expected in HbC heterozygotes. The synthesis ratio (beta A+ beta C/alpha) indicated an alpha-thalassaemia defect with two non-functional alpha genes, which did not correlate with the degree of haemolysis and anaemia displayed by the patient. The DNA analysis of the alpha-genes clusters revealed a defect combination -SEA/-alpha 3.7. The haematological data and the physiopathology of this atypical case are compared with the typical HbH disease found in a first cousin of the propositus. Data on the globin chains expression and on the formation of beta A and beta C homotetramers in HbH/HbC disease are presented.

Adult↗
PubMed1996

Fluorouracil selectively spares acute myeloid leukemia cells with long-term growth abilities in immunodeficient mice and in culture.

A subset of leukemic cells is assumed to maintain long-term growth of acute myeloid leukemia (AML) in vivo. Characterization of these AML progenitor cells may further define growth properties of human leukemia. In vitro incubations with 5-fluorouracil (5-FU) have been used for enrichment of normal primitive hematopoietic stem cells. By analogy to normal hematopoiesis, it was hypothesized that primitive leukemic stem cells might be kinetically more inactive than colony-forming cells (colony-forming units-AML [CFU-AML]). To examine this hypothesis, conditions were established for incubation with 5-FU that eliminated all CFU-AML. These conditions selected a 5-FU-resistant AML fraction that was evaluated for its capacity for long-term growth by transplantation into mice with severe combined immunodeficiency (SCID) and long-term culture in the quantitative cobblestone area-forming cell (CAFC) assay. Transplantation of the 5-FU-resistant fraction of four cases of AML into SCID mice resulted in growth of AML. Whereas no CFU-AML survived, 31% to 82% of primitive (week-6) CAFC were recovered from the 5-FU-treated cells. Hematopoietic cells proliferating in the CAFC assay were shown to be leukemic by cytologic, cytogenetic, or molecular analysis. The reduction of AML growth as determined by outgrowth of AML in SCID mice was in the same order of magnitude as the primitive (week-6) CAFC reduction. This indicates that both assays measure closely related cell populations and that the CAFC assay can be used to study long-term growth of AML. These results show a hierarchy of AML cells that includes 5-FU-resistant progenitors. These cells are characterized as primitive (week-6) CAFC and as leukemia-initiating cells in SCID mice.

Acute Disease↗
PubMed1996

Long-term leukemia-initiating capacity of a CD34-subpopulation of acute myeloid leukemia.

Acute myeloid leukemia (AML) proliferation in vivo is maintained by a small fraction of progenitor cells. These cells have been assumed to express an immature phenotype and to produce most colony-forming units (CFU-AML). For one case of AML (French-American-British [FAB] M1, normal cytogenetics), we examined the capacity of the CD34+ (25% of unseparated AML cells) and CD34- fractions to initiate leukemia in severe combined immunodeficient (SCID) mice. In addition, the production of CFU-AML and nucleated cells (NC) of these subsets was investigated in long-term bone marrow culture (LTBMC). The frequencies of cobblestone area-forming cells (CAFC) were also estimated; early appearing cobblestone areas (CAs) are indicative of relatively mature progenitors and late CAs represent the progeny of primitive progenitors. In mice transplanted with CD34- (98% pure) or CD34+ (98% pure) grafts, similar AML cell growth was seen throughout an observation period of 106 days. The capacity to establish long-term growth from the CD34- cells was confirmed by renewed outgrowth after retransplantation. In vitro, the CD34- fraction contained both immature and mature CAFCs and produced high numbers of CFU-AML and NC in LTBMC. The CD34+ fraction produced only small numbers of CFU-AML, NC, and mature CAFCs. Therefore, the expression of CD34 and the content of CFU-AML were not associated with long-term growth of AML. However, similar frequencies of primitive CAFCs were observed in both fractions. Thus, both CD34- and CD34+ subsets of this AML sample contained immature progenitors with the capacity to initiate long-term AML growth as characterized in vivo (in SCID mice) as well as in vitro (in CAFC assay), indicating asynchrony between functional and immunophenotypical maturation of AML progenitor cell compartments.

Animals↗
PubMed1995

Conditions for engraftment of human acute myeloid leukemia (AML) in SCID mice.

Transplantation of human AML into severe combined immunodeficient (SCID) mice provides a useful experimental model but graft failures have been reported. We investigated the influence of a number of factors on the outgrowth of AML in the SCID mouse bone marrow (BM). The transplantation route and total body irradiation (TBI) were examined using the cell line HL-60 as a model for AML. The role of graft size and recombinant human IL-3 (IL-3) were investigated with patient samples of AML cells. Intravenous transplantation was demonstrated to be superior to intraperitoneal transplantation. Pretransplant conditioning resulted in a dose-dependent increase of AML growth in the SCID mouse. Cell dose titrations ranging from 3 x 10(7) - 3.6 x 10(5) AML cells i.v. per mouse revealed a minimum of 1.1 x 10(6) required for reproducible engraftment. Earlier and more extensive infiltration by human AML cells was seen following injection of greater cell numbers. IL-3 given post-transplantation SCID mouse recipients, promoted AML growth in three cases, whereas a fourth AML cell specimen also grew without support of IL-3. In vitro growth factor responsiveness of AML cells to IL-3 did not predict IL-3 dependence of AML growth in vivo.

Acute Disease↗
PubMed1992

[The detection and analysis of leptospiral DNA in patients' serum of early leptospirosis by polymerase chain reaction and DNA hybridization with digoxigenin-AMPPD].

We have detected and analysed the leptospiral DNA in serum of patients with early Leptospirosis from the epidemic area of China by PCR and DNA hybridization with Digoxigenin (Dig)-3-(2'-Spiroadamantane)-4-methoxy-4-(3"-phosphoryloxy)- phenyl-1,2-dioxetane (AMPPD) to develop a sensitive, specific and reliable technique for the early diagnosis of leptospirosis, and full satisfactory results have obtained. Fourteen serum specimens from patients with leptospirosis proven by blood culture and serological test were prepared according to Boom's methods for PCR test, and oligonucleotide primers, named G1 G2, were obtained from a genomic library of leptospira interrogans. PCR amplification with serum specimens was performed. Each cycle of amplification consisted of denaturation at 94 degrees C for 1 min, annealing at 55 degrees C for 1 min and elongation at 72 degrees C for 2 min. Each sample was subjected to 32 cycles. The amplified DNA were separated by electrophoresis with 2% agarose gel and hybridized with the homologous DNA probe labelling with Dig-AMPPD by means of Southern blotting. All of 14 samples revealed the presence of leptospira and the strong signals were visualized with homologous DNA probe hybridization by Southern blotting. Negative and positive controls appeared correctly. The DNA fragment generated from PCR amplification homologically hybridized with the DNA of 16 strains which are from Yasudas' genomic species and represent the different genomic groups of leptospires. The single recognized band (about 400 bps) from 6 out of the 16 strains has come out which are representative of the principal strains in Sichuan, China.(ABSTRACT TRUNCATED AT 250 WORDS)

Adamantane↗
PubMed1989

Pericardial fibrosis following busulfan treatment.

A case is reported of pericardial fibrosis after busulfan treatment in a man with chronic myeloid leukaemia. In the absence of any other explanation, we assume that busulfan may have been the cause of pericardial fibrosis in this patient. Other drugs causing pericardial fibrosis are discussed.

Busulfan↗
PubMed1988

Determination of the growth fraction in monoclonal gammopathy with the monoclonal antibody Ki-67.

The monoclonal antibody Ki-67 reacts with a nuclear antigen that is present only in proliferating cells. The proportion of Ki-67 positive cells may therefore serve as a reliable measurement for the growth fraction in normal and neoplasmic cell populations. We have tested the significance of the MoAb Ki-67 in the classification of monoclonal gammopathy and compared the results with the plasma cell labelling index. In benign monoclonal gammopathy the percentage of Ki-67 positive plasma cells (median 1.6%) was significantly lower than in untreated multiple myeloma (median 9.6). Among the patients with more than 10% Ki-67 positive plasma cells there were some very short survivors. The largest growth fractions (median 41.8%) were found in patients with relapsing multiple myeloma indicating here a different growth pattern more resembling the high-grade lymphomas. A linear correlation between the proportion of Ki-67 positive plasma cells and the labelling index was not found. Determination of the plasma cell growth fraction with the monoclonal antibody Ki-67 in monoclonal gammopathy may help to discriminate benign monoclonal gammopathy from multiple myeloma and will probably identify a subgroup of multiple myeloma patients with a poor prognosis, including those with relapsing multiple myeloma.

Antibodies, Monoclonal↗
PubMed1985

Inactivation of chlorophyllase by negatively charged plant membrane lipids.

Chlorophyllide combines spontaneously not only with phosphatidylcholine (PC) liposomes but also with various other (plant) lipids dispersed in an aqueous medium. The lipid-associated chlorophyllide is highly fluorescent and the fluorescence yield is virtually independent of the nature of the lipid. Chlorophyllase (chlorophyll chlorophyllidohydrolase, EC 3.1.1.14) activity assays that are based on the determination of this chlorophyllide fluorescence show that phosphatidylglycerol (PG), and also sulphoquinovosyldiacylglycerol (SQDG), associate with isolated chlorophyllase, thereby inactivating the enzyme in a co-operative way. The extent of this inactivation depends on the pH and ionic strength of the reaction medium and can be completely reversed by divalent cations (Mg2+). The inhibition of chlorophyllase effected by free PG liposomes can be counteracted by electrically neutral lipids at relatively high concentration (PC and also chloroplast lipids). Digalactosyldiacylglycerol (DGDG) is not effective in this respect. When PG has been incorporated in PC or DGDG liposomes, its ability to inhibit chlorophyllase activity is reduced. Whereas the remaining chlorophyllase-inactivating effect of PG, incorporated in PC, can still be reversed by Mg2+, this is not found when enzyme inactivation is caused by PG incorporated in DGDG. The results reported here are consistent with those obtained earlier concerning the stabilization of chlorophyllase by PG and PG/galactolipid mixtures (Lambers, J.W.J., Verkleij, A.J. and Terpstra, W. (1984) Biochim. Biophys. Acta 786, 1-8). They are discussed in terms of the regulation of chlorophyllase activity by lipids surrounding the enzyme and by divalent cations.

Carboxylic Ester Hydrolases↗