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H Wessels

Publications and source records attributed to H Wessels.

At least 19 recordsLinked to original sources
PubMed2001

A novel chromosomal translocation t(3;5)(q12;p15.3) and loss of heterozygosity on chromosome 22 in a multifocal follicular variant of papillary thyroid carcinoma presenting with skin metastases.

Classic genetic rearrangements in papillary carcinoma of the thyroid involve the RET- or TRK proto-oncogenes. We report a novel chromosomal translocation t(3;5)(q12;p15.3), confirmed by fluorescence in situ hybridization, in a multifocal follicular variant of a papillary carcinoma of the thyroid in a 79-year-old woman, with skin metastases as a presenting symptom. Three years earlier, another cutaneous metastasis on her scalp was misdiagnosed as hidradenoma. Four tumour foci were recognized in the thyroid, two with a follicular variant of papillary carcinoma. To detect loss of heterozygosity, 14 chromosomes were investigated with 59 microsatellite markers. A clonal relationship was detected between the two foci of tumour in the thyroid gland containing follicular variant of papillary carcinoma and one of the skin lesions tested, all demonstrating loss of heterozygosity (LOH) in the same region of chromosome 22. Based on earlier reports, the low rate of LOH detected is in agreement with the diagnosis papillary carcinoma of the thyroid. Whole body scintigraphy performed after ablative therapy with radioiodine revealed multiple metastases in the lungs and skeleton. After repeated radioiodine therapy, thyroglobulin under thyroxine suppression became undetectable and post-therapeutic scintigraphy revealed important regression of metastases.

Aged↗
PubMed1999

Triggering noncycling hematopoietic progenitors and leukemic blasts to proliferate increases anthracycline retention and toxicity by downregulating multidrug resistance.

Expression of the multidrug resistance (MDR) mechanisms P-glycoprotein (Pgp) and MDR-related protein (MRP) decrease cellular retention and consequently cytotoxicity of anthracyclines. MDR is expressed on normal human hematopoietic progenitors and leukemic blasts. Normal CD34(+) progenitors showed rhodamine efflux in 20% to 30% of the cells, which could be blocked by verapamil. These cells appeared noncycling, in contrast to the proliferating rhodamine bright (RhoB) cells. We postulated that MDR expression can be downregulated by proliferation induction. Triggering rhodamine dull (RhoD) CD34(+) cells to proliferate indeed resulted in a higher rhodamine retention and significantly decreased efflux modulation by verapamil (P =.04). Also in acute myeloid leukemia (AML), the proliferation rate (percentage S/G(2)+M and Iododeoxyuridine labelings index) was significantly less in the RhoD blasts (P </=. 008) and proliferation induction of RhoD blasts resulted in increased rhodamine retention. Anthracycline cytotoxicity was less for RhoD than RhoB cells in both normal progenitors and leukemic blasts. Proliferation induction of the RhoD cells resulted in increased anthracycline sensitivity. We conclude that noncycling progenitors, both normal and leukemic, have a relatively high MDR expression. Triggering these cells into proliferation downregulates MDR expression. These findings can be exploited to overcome MDR in the treatment of AML patients.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1999

Translocations (X;10)(p22;q24) and (1;10)(q21;q11) in a follicular adenoma of the thyroid without apparent involvement of the RET protooncogene.

We report here the cytogenetic analysis of a follicular adenoma of the thyroid which revealed an abnormal clone with a t(X;10)(p22;q24) and a t(1;10)(q21;q11) together with normal cells. Fluorescence in situ hybridization (FISH) with YACs 273E3 and 344H4, which are located on 10q11.2 and are specific for the RET protooncogene, showed no abnormalities. It would therefore appear that this gene is not involved in the particular tumor, as has been reported in a number of papillary thyroid carcinomas. Several chromosomal aberrations have been suggested as been specific for follicular thyroid adenoma. However, until now, only a few such cases have been reported which involve structural abnormalities of chromosomes 10q11.2 and 10q24. We believe this to be the first report of a follicular thyroid adenoma with a t(X;10)and a t(1;10).

Adenoma↗
PubMed1997

Effects of day care on the development of cognitive abilities in 8-year-olds: a longitudinal study.

In Göteborg, Sweden, 146 children (72 girls) were enrolled in a longitudinal study when they averaged 16 months of age. None of the children had experienced regular out-of-home care yet, but within 3 months, 54 entered center care and 33 entered family day care. Quality of home and out-of-home care environments, child temperament, and the development of verbal abilities were assessed regularly during preschool years. When they were 8 years old (2nd grade), cognitive ability tests were administered to the 123 children (65 girls) still in the study. Tested ability was related to the number of months children had spent in center-based day care before 3.5 years of age. Child care quality predicted cognitive abilities among children who had spent at least 36 months in out-of-home care during their preschool years. Both tested and rated cognitive abilities in 2nd grade were related to earlier measures of verbal ability and to paternal involvement during preschool years.

Aptitude↗
PubMed1997

A low but functionally significant MDR1 expression protects primitive haemopoietic progenitor cells from anthracycline toxicity.

Pgp is expressed on normal haemopoietic progenitor cells. The significance of the efflux pump in protecting normal progenitors for anthracycline toxicity is not defined and is the subject of this study. Pgp was measured in CD34+ progenitors with a rhodamine efflux assay. A high efflux, modulated by verapamil, was only found in a distinct subpopulation (20-30%). Pgp measured by the monoclonal antibody antibody (MoAb) MRK-16 was low in the rhodamine dull, but significantly (P < 0.04) higher than in the rhodamine bright cells. Reverse transcriptase polymerase chain reaction (RT-PCR) of MDR1 mRNA showed a very weak signal in both populations. In a single-cell clonogenic assay, rhodamine dull cells appeared less sensitive to anthracyclines (IC50 daunorubicin 0.005 microg/ml; adriamycin 0.03 microg/ml) compared to rhodamine bright cells (IC50 daunorubicin 0.0025 microg/ml; adriamycin 0.01 microg/ml). Furthermore, verapamil significantly (P < 0.05) potentiated anthracycline toxicity only in the rhodamine dull cells, proving its Pgp-specific modulating effect. Rhodamine dull cells gave larger and more mixed colonies compatible with a more primitive origin. Although detection with MoAbs and RT-PCR revealed a low Pgp level, functionally this Pgp appeared to be very important in protecting primitive progenitors against anthracycline toxicity. This protection can be jeopardized by administration of Pgp modulators.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1997

Characterization of a novel malignant B cell line with t(14;18) and t(4;11) established from a patient with acute monoblastic leukemia.

The severe combined immunodeficient (SCID) mouse model is an important tool with which to study new strategies for treating hematologic neoplasia. For these experiments, a large number of human cell lines growing in SCID mice are a prerequisite. We describe a new Epstein-Barr virus (EBV)-positive B cell line, designated BEVA, with a complex karyotype including translocations t(14:18)(q32;q21) and t(4;11) (q21;q23) that meets this need. As demonstrated by Southern blot analysis, BCL2 at 18q21, but not MLL/ALL1 at 11q23, was involved in these translocations. BEVA cells coexpressed lymphoid (IgG-kappa, CD19, CD20, CD21, and CD24) and myeloid (CD11b, CD15, and CDw65) markers. Interestingly, the cell line was established from the bone marrow culture of a patient with acute myeloid leukemia (AML). Examination of bone marrow biopsy specimens suggested the presence of non-Hodgkin's lymphoma (NHL) in this patient in addition to AML. In vitro and in vivo growth characteristics of the BEVA cell line were compared with the previously described EBV-positive B cell line DoHH2, also carrying a translocation t(14;18)(q32;q21). These DoHH2 cells additionally expressed CD10, whereas, in contrast to BEVA cells, only a small population of DoHH2 cells showed expression of CD44. Both cell lines showed similar growth characteristics in vitro, but reacted differently to cytokines, including interleukin (IL)-4, IL-6, IL-7, and alpha-interferon (IFN). Upon inoculation in SCID mice, marked differences were observed in the dissemination patterns of the BEVA or DoHH2 cells. Although both cell lines circulated in the blood and were predominantly found in murine bone marrow and lymphoid tissues, DoHH2 cells infiltrated the murine spleens, whereas BEVA cells could only rarely be detected in these tissues. In contrast to DoHH2 cells, BEVA cells gave rise to tumor masses in liver, kidney, and para-aortal or mesenteric lymph nodes. The relationship between these in vitro differences and the observed differences in dissemination of both cell lines is discussed.

Animals↗
PubMed1996

Relationship of plasma cholesteryl ester transfer protein to HDL cholesterol. Studies in normotriglyceridemia and moderate hypertriglyceridemia.

To evaluate the independent effect of cholesteryl ester transfer protein (CETP) on HDL concentrations in humans, we measured lipids, lipoproteins, postprandial lipemia after an oral fat load, CETP mass, and the activities of CETP, lipoprotein lipase (LPL), and hepatic lipase in 16 healthy, normotriglyceridemic men and in 23 men with moderate, primary hypertriglyceridemia on an American Heart Association Step I diet. Fasting triglycerides and postprandial lipemia were increased and HDL cholesterol (HDL-C) was decreased in hypertriglyceridemic men compared with control subjects (P < .001). In the normotriglyceridemic group, CETP mass (P < .001) and activity (P < .005) were directly related to LPL activity After statistical adjustment for this close association, no significant relationship of CETP to HDL-C independent of LPL activity could be demonstrated in the normotriglyceridemic subjects. In contrast, CETP was unrelated to LPL activity in the hypertriglyceridemic subjects, but CETP concentrations showed a close inverse relationship to HDL-C (r = -.504, P = .014). Structural equation modeling of the association structures between HDL and fasting and postprandial triglycerides, endothelial lipases, and CETP in both groups indicated that the overall regression models for the two groups differed (P < .05). Specifically, the associations between CETP mass and activity and HDL-C differed between both groups (both P < .01). We conclude that high-normal CETP levels lower HDL-C in nonsmoking, nonobese men with moderate, primary hypertriglyceridemia on a hypolipidemic diet, but not in healthy, normotriglyceridemic men on an unrestricted diet. Thus, variation in CETP plasma concentrations may contribute to the high-triglyceride, low-HDL phenotype.

Adult↗
PubMed1995

The Nijmegen modification of the Bethesda assay for factor VIII:C inhibitors: improved specificity and reliability.

Antibodies against factor VIII coagulant activity can appear in haemophiliacs who are treated with factor VIII preparations but also spontaneously in non-haemophiliacs. The Bethesda assay is the most commonly used method to detect these antibodies, but it lacks specificity especially in the lower range resulting in unreliable data. Two modifications are proposed and tested to resolve the imperfections: 1. Buffering the normal plasma used in the assay- and control mixture with 0.1 M imidazole to pH 7.4. 2. Replacing the imidazole buffer in the control mixture by immunodepleted factor VIII deficient plasma. These modifications allow better discrimination between positive and negative samples and improve reliability.

Antibodies↗
PubMed1995

Detection of incorporated iododeoxyuridine in colonies by immunoperoxidase staining: a novel method to measure the proportion of cycling colony-forming cells.

In vitro suicide by tritiated thymidine (3H-TdR), hydroxyurea (HU), or cytosine arabinoside (Ara-C) is assumed to reflect the proportion of colony-forming cells in S-phase at the time of exposure. However, these techniques are not always accurate. Nonradioactive iododeoxyuridine (IdUrd) is incorporated into DNA during S-phase and can be detected by monoclonal antibodies. In the present study, a new IdUrd application was developed to investigate the kinetics of hematopoietic progenitor cells. After incubation with IdUrd, colony-forming cells were cultured in semisolid assay. An immunoperoxidase staining protocol was developed to detect IdUrd in cells of colonies in agar. Colony-forming cells in S-phase during the IdUrd exposure were postulated to give rise to IdUrd+ colonies, whereas non-S-phase cells would generate IdUrd- colonies. Toxicity, sensitivity, and IdUrd inactivation studies indicated that progenitor cells could safely be pulse-labeled for 2 hours with 40 microM IdUrd, whereas prolonged labeling with 1 microM IdUrd was at least feasible for 5 days. Molt-4 cells and normal bone marrow cells were used to compare IdUrd pulse-labeling with 3H-TdR suicide. Part of the Molt-4 cells were enriched for G1- and S-phase cells by counterflow centrifugation. The bone marrow cells were either unstimulated or stimulated with growth factors. As a result, the accuracy of both techniques could be tested in populations with different quantities of S-phase cells. Wide confidence intervals of the suicide technique contrasted with the small confidence intervals obtained with IdUrd pulse-labeling. For instance, the fraction of Molt-4 cells with 27.8% S-phase cells contained 17.7% (confidence interval -8.2 to 43.6%) clonogenic cells in S-phase when determined with 3H-TdR suicide. Of this fraction, the percentage of clonogenic cells in S-phase was 30.6% with a confidence interval of 25.5 to 36.2% when determined with IdUrd pulse-labeling. In our hands, the IdUrd pulse-labeling was more accurate than the 3H-TdR suicide technique. Thus far, kinetic studies of progenitors have been limited to the determination of the fraction of S-phase cells by suicide techniques. By prolonged IdUrd labeling, it is now possible to determine the proliferating fraction of progenitor cells.

Autoradiography↗
PubMed1993

Plasma and cellular pharmacokinetics of m-AMSA related to in vitro toxicity towards normal and leukemic clonogenic bone marrow cells (CFU-GM, CFU-L).

Plasma and cellular pharmacokinetics of m-AMSA were investigated in 5 patients with acute leukemia, using HPLC. The pharmacokinetic data served as a guideline for in vitro toxicity tests on clonogenic bone marrow cells. m-AMSA was administered as a 3-hour intravenous infusion of 100 mg/m2. Median plasma and nucleated blood cell peak concentrations were 1.25 and 6.36 micrograms/ml followed by biphasic elimination with a median T1/2 alpha alpha of 1.6 h and 0.3 h and a median T1/2 beta of 5.0 h and 5.0 h respectively. Median plasma and cellular area under the curve (AUC) for a 24-h period amounted 6.2 micrograms.h/ml and 49.8 micrograms.h/ml respectively. In vitro cellular uptake was maximal at least within 30 minutes. No differential toxicity for CFU-GM and CFU-L was observed in relation to exposure time. Median IC50 for CFU-GM and CFU-L was 2.2, 1.8 and 1.6 micrograms/ml after incubation periods of resp. 0.08, 4 and 24 h. The corresponding m-AMSA concentration x time products to achieve 50% inhibition (IAUC50) were 0.18, 7.2 and 38.4 micrograms.h/ml, respectively. 48-h prestimulation of the clonogenic bone marrow cells with Human Placenta Conditioned Medium increased sensitivity (median 1.7 x) after 4 h incubation with mAMSA. Short exposure provides maximal, concentration-related, cellular uptake, resulting in effective inhibition of growth of clonogenic bone marrow cells.

Acute Disease↗
PubMed1991

S-phase DNA content and aneuploidy of immunophenotypic defined subpopulations in acute myeloid leukemia determined by multi-parameter flow cytometry.

One of the major limitations of DNA flow cytometry (FCM) in hematologic malignancies is the lack of information about the proliferation activity of subpopulations of the heterogeneous bone marrow (BM) compartment. We studied the S-phase DNA content of immunophenotypically defined BM subpopulations (CD2+; CD19+; CD2/CD19+; glycophorin-A+; CD14+; CD13+; CD33+ and CD13/CD33+) in 18 patients with acute myeloid leukemia (AML), including three patients with M6 AML. The results were compared with the findings in twelve normal BM aspirates. The measurements were performed using a special protocol for bivariate FCM of DNA content and surface immunofluorescence (s-IF). In patients with AML the proportion of BM cells expressing the myelomonocytic and monocytic markers (M1-M5 AML) or erythroid marker (M6 AML) was expanded. However, in many patients other subpopulations were 4% or higher permitting the calculation of their S-phase DNA. No essential differences in median S-phase DNA percentages of the distinct subpopulations were observed between normal and leukemic bone marrow though the ranges in AML patients were much wider. These data suggest that AML is not characterized by an increased nor a decreased proliferation activity, but rather by a situation of cell growth independent to the normal regulatory mechanisms. Additional information was obtained upon DNA aneuploidy using CD2+ or CD2/CD19+ cells as an intrinsic DNA standard which allowed us to define differences in the DNA index as small as 2% as aneuploid. This approach appeared suitable for detecting small-degree numerical chromosomal aberrencies, as found by cytogenetics, in 4/6 cases.

Adult↗
PubMed1990

Trisomy 13 and myelodysplastic syndrome.

The clinical and cytogenetic data of a patient with myelodysplastic syndrome-refractory anemia with excess blasts (MDS-RAEB) and trisomy 13 as the sole abnormality are presented. This appears to be only the second report of such a patient. The presence of trisomy 13 is confirmed by in situ hybridization using an alphoid repeat probe L1.26, which is specific for the centromeres of both chromosomes 13 and 21.

Aged↗
PubMed1989

Interference of coumarin therapy with the "Heptest" owing to declining prothrombin concentrations.

The Heptest kit (Haemachem, Inc., St. Louis, MO) for quantifying heparin in plasma is based on heparin-mediated inhibition of factor Xa, resulting in prolongation of clotting time. In 19 of 55 plasma samples obtained from 32 patients concurrently receiving coumarin and heparin, Heptest results exceeded true heparin values by more than 0.2 int. unit/mL; four samples showed a deviation exceeding 0.4 int. unit/mL. We show here that these deviations are caused by coumarin-induced decreases of plasma prothrombin. This problem can be circumvented by adding purified prothrombin or normal plasma to the assay mixture.

Coumarins↗
PubMed1988

A new multichamber counterflow centrifugation rotor with high-separation capacity and versatile potentials.

A new closed system for counterflow centrifugation (elutriation) is described. The system was developed to increase the capacity of counterflow centrifugation in order to be able to separate bone marrow intended for allogeneic bone marrow transplantation within 3 h. The rotor has the capacity for up to four separation chambers, offering the possibility of separating either a single-cell suspension under equal or differing conditions, or four different suspensions simultaneously. Profiles of low-density nucleated cells from normal blood were shown to be identical after elutriation in four different chambers. Leucocytes could be depleted from platelet concentrates without significant loss. Most (98%) of the lymphocytes were removed from donor marrow intended for transplantation within 3 h and the recovery of myeloid and erythroid clonogenic cells in the graft was similar to that obtained from the standard single chamber centrifuge.

Bone Marrow Cells↗
PubMed1987

Improved flow cytometry of cellular DNA and RNA by on-line reagent addition.

Acridine orange (AO) staining enables flow cytometric measurement of cellular DNA and RNA. With the conventional procedure, red and green fluorescence intensities alter considerably in time, affecting the reliability and reproducibility of the results. A standardized simple technique of AO staining is described that keeps the time between addition of detergent and AO and the subsequent measurement constant. Measurements by means of this on-line method appear to be much more reproducible in comparison to those obtained using the conventional procedure.

Cell Line↗
PubMed1987

In-vitro studies on phosphorylation and dephosphorylation of cytosine arabinoside in human leukemic cells.

The cytotoxic effect of cytosine arabinoside (ara-C) depends on the capacity of cells to form and retain intracellularly the phosphorylated metabolite cytosine arabinoside triphosphate (ara-CTP). In this study accumulation and cellular retention of ara-CTP have been measured in vitro in the bone marrow cells of 69 patients with acute leukemia. Cells were incubated with 3H-ara-C and the amount of ara-CTP formed was determined after separation of the nucleotides by thin-layer chromatography. Phosphorylation of ara-C to ara-CTP appeared to be a saturable process. The Km-equivalents varied between 1.1 and 16.2 microM ara-C. Maximal ara-CTP formation ranged from 12 to 125 pmol ara-CTP/10(6) cells in 30 min. The phosphorylation activity did not correlate with the percentage of S-phase cells. The intracellular half-life time of ara-CTP measured in vitro ranged from 53 to 210 min. Phosphorylation of ara-C was comparable in patients with acute myeloid leukemia (n = 51) and in patients with acute lymphoblastic leukemia (n = 18). Ara-CTP elimination appeared slower in lymphoblasts than in myeloblasts. The average intracellular ara-CTP level in relapsed patients (n = 34) appeared higher than in previously untreated patients (n = 52). The less favourable outcome of second remission induction therapy with conventional doses of ara-C compared to the first remission induction treatment is not explained by an alteration in the intracellular metabolism of ara-C.

Bone Marrow↗