PubMed Health⌕ Search

Biomedical subjects

E Smeland

Publications and source records attributed to E Smeland.

At least 19 recordsLinked to original sources
PubMed2001

High-dose therapy in patients with Hodgkin's disease: the use of selected CD34(+) cells is as safe as unmanipulated peripheral blood progenitor cells.

Register data suggest that patients with Hodgkin's disease (HD) given high-dose therapy (HDT) with peripheral blood progenitor cells (PBPC) have a less favourable prognosis as compared to those given bone marrow as stem cell support. Since this can be due to infusion of tumour cells contaminating the PBPC grafts, we initiated a feasibility study in which PBPC grafts from HD patients were purged by CD34(+) cell enrichment. Controversy exists about whether the use of CD34(+) enriched stem cells leads to a delayed haematological and immune reconstitution. We compared these parameters, including risk of infections and clinical outcome after HDT, in patients with HD given either selected CD34(+) cells or unmanipulated PBPC as stem cell support. From October 1994 to May 2000, 40 HD patients with primary refractory disease or relapse were treated with HDT and supported with either selected CD34(+) cells (n = 21) or unmanipulated PBPC (n = 19) as stem cell support. All patients had chemosensitive disease at the time of transplantation. A median of 5.8 (range 2.7-20.0) vs 4.5 (range 2.3-17.6) x 10(6) CD34(+) cells per kilo were reinfused in the CD34(+) group and PBPC group, respectively. No difference was observed between the two groups with regard to time to haematological engraftment, reconstitution of B cells, CD56(+) cells and T cells at 3 and 12 months and infectious episodes after HDT. Two (5%) treatment-related deaths, one in each group, were observed. The overall survival at 4 years was 86% for the CD34(+)group and 74% for the PBPC group with a median follow-up of 37 months (range 1-61) and 46 months (range 4-82), respectively (P = 0.9). The results of this study demonstrate that the use of CD34(+) cells is safe and has no adverse effects either with respect to haematological, immune reconstitution or to infections after HDT.

Adolescent↗
PubMed1998

[Chronic lymphatic leukemia. Immunophenotyping as an aid to correct diagnosis].

The purpose of the study was to examine the validity of the primary diagnosis in chronic lymphocytic leukemia based on clinical and morphological criteria, and to examine the role of immune phenotyping for correct diagnosis in an unselected population-based group of patients. Over a 2-year period leukemic cells from 222 of 235 patients in Norway with a recent clinical diagnosis of chronic lymphocytic leukemia (CLL) were immune phenotyped in order to find cases erroneously diagnosed as CLL. Median age was 72.5 years, and the ratio of men to women was 1.47. At the time of diagnosis, 77% of the patients were in Binet stage A and 23% in stage B or C. Immune phenotyping, in some patients followed by lymph node or bone marrow biopsy, showed a different diagnosis in 11 (5%) of 222 patients: prolymphocytic leukemia, four patients (three B-cell and one T-cell); morbus Waldenstrøm, one patient; T-cell CLL, one patient; hairy cell leukemia, one patient; mycosis fungoides, one patient; mantle cell lymphoma, one patient; monocytoid B-cell lymphoma, one patient and immunoblastic lymphoma one patient. In eight of these 11 patients, the clinical features or morphology, or both, were atypical for CLL, but this was not recognized at the time of diagnosis. Thus, immune phenotyping is valuable for correct diagnosis in a small subgroup of patients with chronic B- or T-cell leukemia, and it is essential in patients with modest lymphocytosis (lymphocytes < 10. 10(9)/1).

Adult↗
PubMed1996

High-dose 7-hydromethotrexate: acute toxicity and lethality in a rat model.

To elucidate mechanisms for methotrexate (MTX)-induced renal and hepatic toxicity, we investigated the acute effects of bolus plus continuous infusion of up to 0.4 g/kg 7-hydroxymethotrexate (7-OH-MTX) in the rat. We demonstrate for the first time in any species the occurrence of acute lethal toxicity within a few hours after 7-OH-MTX administration. Serum concentrations of 7-OH-MTX measured at the time of death were 1.4 mM (mean), about one-half of those achieved in some patients after infusion of high-dose MTX (HD-MTX) in the clinic. The data suggest an approximate LD50 (the dose lethal to 50% of the study population) of 0.3 g/kg and a steep dose/lethality curve for 7-OH-MTX. Moreover, acute renal and hepatic toxicity occurred as evidenced by severe morphological findings and increased serum levels of creatinine and liver transaminases. In all rats subjected to continuous infusion of 7-OH-MTX, yellow microscopic precipitations were apparent in the kidney tubules. Crystallization was also seen in bile ducts of the liver in some of the rats. These results further support that the formation of 7-OH-MTX is disadvantageous and that reported attempts to prevent its formation during MTX treatment are warranted.

Animals↗
PubMed1996

Purging of tumor cells from leukapheresis products: experimental and clinical aspects.

Peripheral blood progenitor cell autografts are being used increasingly in conjunction with high-dose therapy of cancer patients, in the belief that these products have a low probability of containing tumor cells. However, recent findings demonstrate that tumor cell involvement is frequent in leukapheresis products. Although the clinical value of purging has not been clinically established by prospective randomized trials, several studies indicate that contaminating tumor cells in autografts contribute to relapse of the disease in the recipients. We describe our experimental and clinical experience in purging tumor cells from leukapheresis products. Based on our work with purging of lymphoma cells from bone marrow by the use of anti-B cell and anti-T cell antibodies and immunobeads, a purging procedure to deplete leukapheresis products of lymphoma cells has been developed. Moreover, we present data showing that breast cancer cells can be efficiently removed from leukapheresis products using antibreast cancer antibodies, either in combination with immunobeads or as immunotoxins. Our experience with enrichment of CD34 cells employing immunobeads in leukaphresis products from patients with breast cancer and lymphomas shows high purity and yield of CD34 cells. In spite of this, contaminating tumor cells can be observed, strongly suggesting that a combination of CD34 cell enrichment and a purging procedure might be warranted.

Antibodies, Monoclonal↗
PubMed1996

Solid-phase method for differential display of genes expressed in hematopoietic stem cells.

A solid-phase differential display method was designed to analyze differential gene expression in samples with low amounts of mRNA. The principle was based on using a biotinylated probe to capture the mRNA and priming both the first-strand synthesis and the subsequent polymerase chain reaction step. Coupling the mRNA to a solid phase during the procedure simplified the purification steps, limited sample loss and enabled rapid handling of mRNA. DNA contamination was also minimized when the mRNA was bound to a solid phase. Optimization of the differential display method was achieved by analyzing both the enzymatic conditions and the required cell amounts. The approach was used for the characterization of genes expressed in the most immature hematopoietic progenitor cells (CD34+CD38-). The majority of the differentially expressed fragments represented previously uncharacterized sequences.

ADP-ribosyl Cyclase↗
PubMed1995

Characterization of a promoter region supporting transcription of a novel human beta-galactoside alpha-2,6-sialyltransferase transcript in HepG2 cells.

In humans, two transcripts encoding beta-galactoside alpha-2,6-sialytransferase (EC 2.4.99.1.) have previously been described. One of the transcripts is widely expressed, whereas the other is restricted to mature B-cells. In this study we demonstrate the existence of a third transcript in the hepatoma cell-line HepG2. The expression of this transcript is controlled by a promoter region which efficiently supports transcription in HepG2 cells, and which harbours putative binding sites for liver-enriched and acute phase inducible transcription factors.

Acute-Phase Reaction↗
PubMed1995

Semiquantitative polymerase chain reaction for t(14;18) in follicular lymphomas: a colorimetric approach.

BACKGROUND: Autologous bone marrow transplantation is increasingly being used in the management of several types of cancer, and to avoid reintroduction of malignant cells, bone marrow purging is often performed. In such cases, sensitive quantitation methods are needed both to assess the efficacy of the purging and for surveillance of patients in remission. Polymerase chain reaction (PCR) has the necessary sensitivity for this application, but it requires that the cancer cells can be recognized by a defined genetic abnormality. In addition, PCR is in principle a qualitative technique and must be modified for quantitative purposes. In follicular non-Hodgkin's lymphomas, the translocation t(14;18) (q32;q21) is common and is used here for model experiments. EXPERIMENTAL DESIGN: A PCR-based method for the quantitation of translocation-positive cells was developed on the basis of coamplification of cancer-specific target molecules with competitor molecules of known concentration. Gel electrophoresis was substituted by a colorimetric quantitation system to cope with patient PCR products of the same size as the competitor product and ease automation of the method at a later stage. Cell line Karpas 422, which contains the t(14;18) (q32;21) translocation, was used to validate the method. The method was used to assess the efficacy of a patient bone marrow purging where the initial infiltration levels were too low for traditional detection systems. RESULTS: A reproducible and near linear response was obtained between 70 pg and 200 ng K422 DNA, equivalent to 10 K422 cells and 30,000 K422 cells, respectively. Bone marrow infiltration in one patient was 0.6 to 0.7% before malignant cell removal and 3 to 7 x 10(-4) after removal. The corresponding figures for the other patient were 2% and 3 to 7 x 10(-4), respectively. CONCLUSIONS: The method presented has a sufficient dynamic range for applications like evaluation of bone marrow purging or monitoring of minimal residual disease. Adaptation of this method to other translocations is discussed.

Base Sequence↗
PubMed1994

Renal and hepatic toxicity after high-dose 7-hydroxymethotrexate in the rat.

To examine directly the hepatic and renal toxicity of 7-hydroxymethotrexate (7-OH-MTX) without interference of the parent compound methotrexate (MTX), we purified and gave 100 mg/kg 7-OH-MTX to rats, a dose resulting in serum levels of 7-OH-MTX comparable with those achieved in the clinic after the administration of high-dose MTX (HD-MTX). After only 5 h, the 7-OH-MTX-treated rats demonstrated 2.6-fold increases in serum creatinine values and 2-fold elevations in serum aspartate aminotransferase (ASAT) levels as compared with the controls. Morphologic evidence of toxicity, however, was apparent only in the kidneys. Intraluminal cellular debris containing membranous material and deteriorated organelles was seen, but no precipitate of the delivered drug. The peak serum concentration of 7-OH was up to 939 microM, and concentrations of 7-OH-MTX declined triphasically, showing a t1/2 alpha value of 2.45 min, a t1/2 beta value of 30.5 min, and a terminal half-life (t1/2 gamma) of 240 min. The total clearance value was 14.5 ml min-1 kg, and the postdistributional volume of distribution (V beta) was 5070 ml/kg. Our results may indicate a direct toxic effect of 7-OH-MTX on kidney and liver cells.

Animals↗
PubMed1993

Interactions of vinblastine and vincristine with methotrexate transport in isolated rat hepatocytes.

The accumulation of methotrexate (MTX) in the presence of vinblastine (VBL) and vincristine (VCR) was studied in isolated rat hepatocytes. In accordance with our recent study on vindesine (VDS), we found VBL and VCR to reduce net MTX accumulation significantly at 15 min after MTX addition. Drug concentrations of 100 microM VBL and 500 microM VCR led to 67% and 82% reductions in intracellular MTX, respectively. Since there was only a slight inhibition of MTX efflux by 100 microM VBL, the accumulation data demonstrate that the major effect of VBL is on MTX influx. Dixon-plot analyses are suggestive of competitive inhibition of the MTX influx, yielding inhibition constants (Ki values) of 55 microM for VBL and 110 microM for VCR. Since the Ki values correspond grossly to plasma levels obtained in humans shortly after the infusion of therapeutic doses of the vinca alkaloids studied herein, the interaction with MTX uptake could serve to diminish the toxicity of MTX to nonmalignant cells.

Animals↗
PubMed1991

The effect of vindesine on methotrexate hydroxylation in the rat.

The effect of vindesine (VDS) on methotrexate (MTX) disposition was studied in bile-drained rats administered VDS prior to [3H]MTX, and in isolated rat hepatocytes and rat liver homogenate concomitantly incubated with MTX and VDS at 37 degrees. In vivo, 7-hydroxylation was reduced by 0.65 mg/kg VDS. In VDS-treated animals, biliary recovery of the MTX dose (50 mg/kg) as 7-hydroxymethotrexate (7-OH-MTX) (1.75 +/- 0.2%, mean +/- SEM) was significantly reduced compared to controls (2.83 +/- 0.57%). In vitro, hydroxylation of MTX (10-200 microM) in hepatocytes was reduced by 14.3 and 66.4% (means) at 12.5 and 100 microM VDS, respectively. With increasing VDS concentrations up to 100 microM, a reduction in intracellular MTX accumulation could account for the decreased MTX hydroxylation. Experiments in a cell free system gave no evidence of inhibition of 7-OH-MTX formation by VDS. In vitro MTX transport studies demonstrated that VDS inhibited the hepatocellular influx of MTX, as (1) the accumulation of MTX corresponded inversely to increasing VDS concentrations and (2) the MTX efflux was not increased by VDS. The apparent Ki for VDS inhibition of MTX influx was 57 microM. We suggest that VDS, by reducing the 7-OH-MTX formation in liver cells, may have implications for combination chemotherapy regimens which include MTX.

Animals↗
PubMed1991

Immunomagnetic isolation of NK and LAK cells.

The present study describes the immunomagnetic isolation of human natural killer (NK) and lymphokine activated killer (LAK) cells. Antibodies against CD56 and sheep anti-mouse IgG-coated magnetic monodisperse particles (Dynabeads M-450) were used for the positive isolation of CD56+ cells from unstimulated mononuclear cells (PBMC). A highly enriched population of CD56+ cells (less than or equal to 3% contaminating cells) was obtained with this method. The cellular yield of CD56+ cells was high (5.3% of the unseparated PBMC). The CD56+ cells remained unactivated after separation and preserved their functional characteristics, as measured by cytotoxic activity against the NK sensitive K562 cells. Incubating the CD56+ cells with IL-2 resulted in high LAK activity, as measured by cytotoxic activity against Daudi cells. Large numbers of functionally active CD56+ cells were obtained from IL-2 stimulated lymphocytes using anti-CD56 coated Dynabeads 450. A further enrichment of effector cells with LAK activity was accomplished by depleting the CD56+ cells for T-cells by anti-CD3 coated Dynabeads M450. The immunomagnetic isolation technique described was easy to perform, did not require expensive equipment and yielded NK and LAK cells of satisfactory purity.

Antigens, Differentiation, T-Lymphocyte↗
PubMed1991

Inhibition of 7-hydroxymethotrexate formation by amsacrine.

The inhibition of methotrexate (MTX) biotransformation to 7-hydroxymethotrexate (7-OH-MTX) by 4'-(9-acridinylamino)-methanesulfon-m-anisidide (mAMSA) was studied in bile-drained rats in vivo and in incubates of isolated rat hepatocytes and rat-liver homogenate in vitro. In vivo, i.v. administration of 10 mg/kg mAMSA prior to [3H]-MTX infusion (50 mg/kg) led to a significant alteration in 7-OH-MTX kinetics. 7-OH-MTX peak concentrations and AUC in bile and serum were reduced by 75% and the recovery of MTX as 7-OH-MTX in bile and urine decreased by 70%, whereas MTX pharmacokinetics remained unaltered. In suspensions of isolated hepatocytes, 10 microM mAMSA led to a 54% decrease in 7-OH-MTX formation. However, the hepatocellular influx and efflux of MTX was not perturbed by mAMSA. Preincubation of rat-liver homogenates with 1.25-10 microM mAMSA reduced the formation of 7-OH-MTX by up to 73%. mAMSA appeared to inhibit MTX hydroxylation competitively, exhibiting a Ki of 3 microM. Due to its inhibition of the MTX-oxidizing system, mAMSA may be beneficial in combination chemotherapy with MTX by reducing 7-OH-MTX-associated toxicity and, possibly, enhancing the cytotoxic effects of MTX.

Amsacrine↗
PubMed1991

Acute hepatotoxicity after high-dose methotrexate administration to rats.

Acute hepatotoxicity after administration of 10-1000 mg/kg methotrexate (MTX) to rats was studied by monitoring serum transaminases, liver morphology, and disposition kinetics of MTX and 7-hydroxy-methotrexate (7-OH-MTX). Half the control rats and rats administered 1000 mg/kg MTX, had their bile duct cannulated. One to 2 hr after administration of 1000 mg/kg MTX, 50% of MTX treated bile-drained rats (Ebc) developed cholestasis despite similar or larger initial bile flow rates than those which did not develop cholestasis (Ebn, controls). In Ebc animals, peak serum ASAT and ALAT levels were 6- and 4-fold higher than that of the control rats, and morphologically, prominent hepatocytic changes and grossly dilated bile canaliculi were found. Immediately prior to cholestasis, the Ebc animals reached biliary 7-OH-MTX levels (8.3 +/- 1.3 mM, mean +/- S.E.M.) which were equivalent to the threshold level for precipitation of 7-OH-MTX in rat bile in vitro, and 3-fold higher than the corresponding levels of 7-OH-MTX in the bile of Ebn rats. Ninety-five % of the drug in the precipitated material was 7-OH-MTX. Hence, 7-OH-MTX may play a role in acute MTX hepatotoxicity, a dose-limiting toxicity that may not be counteracted by leukovorin rescue.

Animals↗
PubMed1989

[Gene technology in the prevention of cancer].

Cancer may develop in connection with rare, genetic diseases or after exceptional, environmental exposures. Most commonly, however, cancer results from an unhappy coincidence of normal, genetic factors and ordinary, environmental conditions. Oncogenes are normal growth genes. Anti-oncogenes are normal regulatory genes which control growth genes. Cancer may result from changes (mutations) in an oncogene (such as in the Philadelphia chromosome), or from the lack of control of normal oncogenes. The latter may be due to loss of function of a suppressor gene (mutation in an anti-oncogene, such as in retinoblastoma) or through a change in the position of an oncogene (such as in Burkitt's lymphoma and in certain leukemias).

Biomarkers, Tumor↗