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M Hokland

Publications and source records attributed to M Hokland.

At least 19 recordsLinked to original sources
PubMed1995

DNA preparation from cryopreserved bone marrow cell samples.

1. Quickly thaw cryopreserved MNCs (1 ml) in 9 ml PBS supplemented with DNase I immediately before use (final concentration: 0.1 mg/ml). 2. Incubate at 37 degrees C for 10 min. 3. Wash twice in PBS supplemented with 2% human AB serum at 4 degrees C. 4. Incubate with saturating amounts of selected MoAbs for 20 min at 4 degrees C. 5. Wash twice in PBS supplemented with 2% human AB serum at 4 degrees C. 6. Immunomagnetic bead separation of viable cells as described by Lea et al. (1). 7. DNA extraction. 8. Measure quality and yield of DNA by spectrophotometry. In conclusion, the DNA extraction method presented here, based on DNase I pretreatment of the cryopreserved cells followed by an immunological selection for viable cells, provides cell suspensions with close to 100% viability; thus, high-quality DNA can be extracted even from cryopreserved cell samples of low initial viability. Furthermore, using this method DNA analyses can be performed on selected cellular subsets if desired. We thus recommend this method for DNA analyses in hematological research when the only materials available are cryopreserved bone marrow samples of low viability.

Bone Marrow↗
PubMed1995

Differential expression levels of the heat shock protein 27 isoforms in pediatric normal, nonleukemic and common acute lymphoblastic leukemia B-cell precursors.

Heat shock protein 27 (hsp27) may function as a regulator of microfilament dynamics and may participate in signal transduction pathways of different cell growth regulators, with the mitogen-activated protein kinase-activated protein (MAPKAP) kinase 2 being a major enzyme responsible for its phosphorylation. Using two-dimensional gel electrophoresis, we have compared the expression levels of two hsp27 isoelectric variants (hsp27 isoforms) M2 (molecular weight, 26 kD; isoelectric point, 6.02) and M3 (molecular weight, 26 kD; isoelectric point, 5.60) in pediatric bone marrow CD19+CD10+B-cell precursors (BCPs) purified from either common acute lymphoblastic leukemia (c-ALL) patients, normal donors, or non-c-ALL patients. Compared with normal BCPs, we found increased hsp27 expressions (M2 isoform) (by a factor 5 to 9 of mean level) in c-ALL as well as in non-c-ALL (nonleukemic) precursors. Though increased phosphorylation of hsp27 (M3 isoform) was observed in BCPs from c-ALL patients at relapse (by a factor 3 of mean level compared with normal BCPs and precursors from c-ALL at diagnosis), which might represent a differential enzymatic activity, this was not distinguishable from that of non-c-ALL patients. Therefore, our studies suggest constitutive differences of hsp27 isoforms between pediatric leukemic BCPs and their relatively low-expressing, immunophenotypically normal bone marrow counterparts. In light of the occasional and possibly transient increase of hsp27 expression during nonleukemic BCP differentiation and the possible role of hsp27 in signal transduction to microfilaments, these differences might be of considerable biologic interest and of importance in future studies of regulated normal or dysregulated leukemic hematopoietic cellular differentiation.

Adolescent↗
PubMed1995

Changes in lymphocyte subpopulations and adhesion/activation molecules following endotoxemia and major surgery.

Major surgery as well as endotoxin-induced sepsis is accompanied by lymphocytopenia in peripheral blood. The purpose of this study was to investigate the redistribution of lymphocyte subpopulations and adhesion/activation molecules on lymphocytes. Twenty-four rats were included in the investigation. Eight rats received an intraperitoneal injection of E. coli endotoxin (2 mg kg-1), eight rats had a sham operation performed while eight rats received isotonic saline and served as a control group. Blood samples were obtained by making an incision in the tail before and 2 and 5 h after surgery or administration of endotoxin or saline. After isolation of lymphocytes by gradient centrifugation, flow-cytometric immunophenotyping was performed using CD2, CD3, CD4, CD8, CD11/CD18, CD20, CD44 and MHC II monoclonal antibodies. Endotoxemia and surgery were both accompanied by increased serum cortisol, lymphocytopenia, and a decrease in CD2, CD3 and CD4 lymphocytes. Only endotoxemia was followed by a decrease in CD8, CD11/CD18 and CD44 lymphocytes in peripheral blood. Our results show that several of the changes in lymphocyte subpopulations following surgery and sepsis are associated with increased serum cortisol. Sepsis is, in addition, accompanied by an upregulation of adhesion receptors.

Animals↗
PubMed1993

A quantitative evaluation of erythropoiesis in myelodysplastic syndromes using multiparameter flow cytometry.

By staining human bone marrow cells with a monoclonal antibody reacting with erythroid precursor cells (AS-E1) and propidium iodide, we have evaluated the proliferative capacity of erythropoiesis in patients with myelodysplastic syndromes (MDS) using flow cytometry. Comparing 36 patients (13 RA/RAS, 13 RAEB, 10 RAEB-t) with 7 normal controls, significant differences in both the percentage of AS-E1+ cells and the fraction of AS-E1+ cells in the S or S-G2M-phase between the four groups were found. Since neither the percentage of AS-E1+ cells nor their fraction in S or S-G2M alone was found to characterize their proliferative activity, we introduced the proliferative fractions of the erythroid cell, i.e. the number of the AS-E1+ cells in S or S-G2M related to all bone marrow cells in S or S-G2M. Applying these parameters, we found significantly increased proliferative AS-E1 fractions in the RA/RAS group compared to the normal controls (p = 0.03 and 0.002) respectively, as well as a highly significant decrease with disease progression.

Antibodies, Monoclonal↗
PubMed1993

Expression and regulation of an interferon-alpha-inducible membrane protein p106 on human hematopoietic cells.

p106 is a human membrane protein of 106 kD previously shown to be inducible by interferon-alpha (IFN-alpha) on Daudi cells. To investigate the role of p106 further, its distribution and inducibility within hematopoietic cells was studied. Multiparameter flow cytometry (FCM) analysis showed that p106 expression was restricted to B cells and monocytes, and in both cell lineages acquired at a late stage of differentiation. Thus, p106 was found on mature B lymphocytes and monocytes in peripheral blood and on a variety of freshly isolated leukemic cells of B and myeloid origin as well as on a variety of cultured B-cell lines. In contrast, no expression was found on T lymphocytes, natural killer (NK) cells or granulocytes. p106 expression could be further induced by IFN-alpha on monocytes and Daudi cells, and this capacity was shown to be selective for IFN-alpha, since no other cytokines tested induced p106. Moreover, IFN-alpha therapy of chronic myeloid leukemia (CML) and hairy cell leukemia (HCL) patients lead to a clearcut induction of p106 on such malignant cells. The distribution of p106 could suggest that it represents an activation antigen. Further studies, including cloning of p106 cDNA, are needed to determine the function of p106.

Cytokines↗
PubMed1992

Postoperative infection and natural killer cell function following blood transfusion in patients undergoing elective colorectal surgery.

The frequency of infection in 197 patients undergoing elective colorectal surgery and having either no blood transfusion, transfusion with whole blood, or filtered blood free from leucocytes and platelets was investigated in a prospective randomized trial. Natural killer cell function was measured before operation and 3, 7 and 30 days after surgery in 60 consecutive patients. Of the patients 104 required blood transfusion; 48 received filtered blood and 56 underwent whole blood transfusion. Postoperative infections developed in 13 patients transfused with whole blood (23 per cent, 95 per cent confidence interval 13-32 per cent), in one patient transfused with blood free from leucocytes and platelets (2 per cent, 95 per cent confidence interval 0.05-11 per cent) and in two non-transfused patients (2 per cent, 95 per cent confidence interval 0.3-8 per cent) (P less than 0.01). Natural killer cell function was significantly (P less than 0.001) impaired up to 30 days after surgery in patients transfused with whole blood. These data provide a strong case against the use of whole blood transfusion in patients undergoing elective colorectal surgery.

Adult↗
PubMed1992

Tissue distribution of adoptively transferred adherent lymphokine-activated killer cells assessed by different cell labels.

Assessment of the tissue distribution of adoptively transferred adherent lymphokine-activated killer A-LAK) cells by use of 51Cr indicated that these effector cells, after an initial phase in the lungs, distributed in high numbers to liver and spleen (30% and 10% of injected dose, respectively). However, when this experiment was repeated with 125IdUrd as cell label, fewer than 2% and 0.5% of the injected cells distributed into liver and spleen respectively. To analyse this discrepancy, we compared the tissue distribution of 51Cr- and 125IdUrd-labelled A-LAK cells with that indicated by alternative direct visual methods for identification of the injected cells, such as fluorescent dyes (rhodamine and H33342) or immunohistochemical staining of asialo-GM1-positive cells. The number of i.v. injected A-LAK cells found in the liver by all visual methods ranged from 1% to 5% of the injected dose, supporting the data obtained with 125IdUrd, whereas 25%-30% of the 51Cr label was consistently found in this organ. Autoradiography of the liver 24 h after i.v. injection of 51Cr-labelled cells revealed a background activity that was four- to fivefold higher than the control level, indicating substantial non-specific accumulation in the liver of 51Cr released from A-LAK cells. We conclude that 51Cr cannot be reliably used in investigations of cell traffic to the liver because of non-specific accumulation of the 51Cr label, particularly in this organ. In contrast, labelling with 125IdUrd or rhodamine and immunohistochemical staining of asialo-GM1-positive cells appear to be reliable and essentially equivalent methods for investigations of the fate of adoptively transferred A-LAK cells. Using these methods, we found that only few A-LAK cells redistribute to the liver upon i.v., i.e. systemic, injection, whereas 40%-50% of locally (intraportally) injected A-LAK cells remain in the liver for at least 24 h.

Animals↗
PubMed1992

Induced and down-regulated proteins in the human cultured hairy cell leukemia line JOK-1 and the Burkitt's lymphoma cell line Daudi during incubation with interferon-alpha: a kinetic study.

To elucidate the mechanism of action of interferon-alpha (IFN-alpha), the effect on cell proliferation and protein synthesis in the human hairy cell leukemia line JOK-1 and the Burkitt's lymphoma cell line Daudi were investigated. While Daudi cells were inhibited in proliferation and in total protein synthesis, no effect was seen on JOK-1 cells. However, high-resolution two-dimensional gel electrophoresis showed that four polypeptides were induced in JOK-1 cells after IFN-alpha incubation, while an additional 11 were induced and two down-regulated in Daudi cells. Kinetic studies revealed that the changes in JOK-1 cells were only temporary (within 8-16 h) and small to moderate in magnitude (less than four-fold). In Daudi cells, the changes for two of these polypeptides were early (within 2 h), for most of them prolonged (at least 24 h), and for three of them of great magnitude (between 6- and 30-fold). Quantitative analytical assessments indicated that four IFN-alpha-inducible polypeptides, present in low amounts of untreated cells, were highly expressed only in sensitive Daudi cells upon IFN-alpha treatment. This observation might indicate a role for these polypeptides in the inhibition of cell proliferation in Daudi cells. Furthermore, six of the other IFN-alpha-modulated polypeptides were synthesized constitutively in JOK-1 cells at levels comparable to those achieved in IFN-alpha-treated Daudi cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Burkitt Lymphoma↗
PubMed1992

Evolution of Ig- and T-cell receptor gene configuration in a Ph1+ hybrid leukemia patient.

In a longitudinal study of a 32-year-old male with Ph1+ hybrid leukemia we have followed the immunophenotype and configuration of Ig- and TCR genes during the course of different chemotherapy regimens directed first against the myeloid and later against the lymphoid components of the disease. We identified changes in all parameters, interpretable as an evolution of the malignant clone resulting in a leukemic switch towards a more lymphoid character. Thus, while the expression of the myeloid antigens CD13 and CD33 decreased, that of CD10 (CALLA) and CD20 (B1) increased. Moreover, while the configuration of the Ig heavy and light chain lambda genes remained constant during the whole period of treatment, that of the Ig light chain kappa gene and TCR beta gene displayed extensive rearrangements after initiation of ALL therapy. Since this patient represents a de novo acute leukemia as evaluated by location of the translocation-breakpoint on chromosome 22, our data clearly indicate that Ig- and TCR gene rearrangements might prove a valuable addition in monitoring Ph1+ hybrid leukemias, providing guidelines for optimizing chemotherapy.

Adult↗
PubMed1992

Interferon-alpha-induced changes in surface antigens in a hairy-cell leukemia (JOK-1), and a Burkitt's lymphoma cell line (Daudi) during in vitro culture.

In further studying the mechanism of action of IFN-alpha in HCL, we cultured the HCL cell line JOK-1 and the IFN-sensitive Burkitt cell line Daudi with and without IFN-alpha and investigated the changes in density of a number of surface antigens by use of mAb and flow cytometry analyses. During culture with IFN-alpha, reproducible changes were induced in both cell lines, which were qualitatively similar but differed quantitatively with small and transient changes in JOK-1. Significant decreases in surface antigen expression were observed for CD 19, 23, 37, and for IgM on both cell lines. Moreover, decreases were seen for CD 10, 22, 45, and MHC class II on Daudi, and for CD 20, 21, 27, and 40 on JOK-1. By contrast, only a few antigens increased in density, including CD 39, A96/G8 and SC9, on both cell lines, CD 22 on JOK-1, and CD 21 on Daudi. The increase in CD 39, A96/G8 and SC9 was probably directly related to the mechanism of action of IFN-alpha, whereas the other changes were most consistent with an unspecific inhibition of protein synthesis, possibly due to an accumulation of cells in G0, even though a differentiating effect cannot be ruled out. Thus, the unique in vivo effect of IFN-alpha in HCL was not paralleled by a specific direct effect on JOK-1 in vitro. Our findings therefore do not support the theory that IFN's mechanism of action in vivo is a direct effect on HC, but suggest that indirect effects are involved.

Antigens, CD↗
PubMed1992

Enumeration of organ-associated natural killer cells in mice: application of a new stereological method.

We here describe a method for estimation of the absolute number of NK cells in various organs of C57BL/6 mice. Using anti-asialo-GM1 heteroantisera to identify NK cells in tissue sections routinely stained by two-layer immunoperoxidase techniques, scoring was performed using light microscopy. Extrapolation to the absolute number of NK cells/organ was done after counting 10 systematically sampled sections of each organ. Due to the thinness of the sections (8 microns) many cells are cut and will appear in at least two sections, and a correction factor was constructed to eliminate this bias. With this method we show that spleens of eight-week-old C57BL/6 male mice contain about 4 x 10(6) NK cells, which is consistent with previous findings obtained by other methods. However, application of this stereological method to liver and lungs revealed the existence of as many as 0.75 and 2.5 x 10(6) NK cells in these organs, respectively, i.e. three to 10 times as many as previously found in single-cell suspensions obtained by enzymatic dissociation of liver and lung tissue. This stereological method for enumeration of the absolute number of small subpopulations of cells is generally applicable to other organs and to other antigens, and does not require the application of cumbersome single-cell isolation procedures, during which an unknown number of cells might be lost.

Animals↗
PubMed1991

Solitary expression of CD7 among T-cell antigens in acute myeloid leukemia: identification of a group of patients with similar T-cell receptor beta and delta rearrangements and course of disease suggestive of poor prognosis.

In a series of 100 acute myeloid leukemia (AML) patients defined by cytochemistry and immunophenotyping, 20 expressed T-lymphocyte associated antigens on the surface of their blasts. While 15 expressed two or more T-cell antigens, five were found to express only CD7. All patients belonged to the French-American-British type M4, and four were under the age of 40. Despite intensive chemotherapy, four never obtained a complete remission and the fifth died of relapse after an allogenic bone marrow transplantation. While 12 randomly selected T-cell antigen negative AML patients showed only few rearrangements in Ig- or T-cell receptor (TCR) genes, such genetic alterations were demonstrated in four of five patients for the TCR delta gene and in all patients for the TCR beta gene. Interestingly, DNA fragments of similar size were demonstrated in three of five patients for both the beta and delta genes. These data suggest that the solitary presence of CD7 among T-cell antigens in otherwise clearcut AML cases identifies a group of patients with similarities in antigen receptor gene configuration as well as outcome.

Acute Disease↗
PubMed1991

Accumulation of adoptively transferred adherent, lymphokine-activated killer cells in murine metastases.

While close contact between lymphokine-activated killer (LAK)/adherent, lymphokine-activated killer (A-LAK) cells and tumor cells is believed to be a prerequisite for initiating the events leading to tumor cell lysis, clear evidence for the ability of these effector cells to infiltrate tumors or tumor metastases in vivo still has to be obtained. In the present study, we report that a significant fraction of adoptively transferred A-LAK cells, labeled with fluorochromes for identification, accumulates in lung and liver metastases of the B16 melanoma, the MCA 102 sarcoma and the Lewis lung carcinoma lines. Thus, 5- to 10-fold higher numbers of A-LAK cells were found in the malignant lesions compared to the surrounding normal tissue. The infiltration seemed very heterogeneous after intravenous injection of moderate numbers of A-LAK cells (15 x 10(6)). However, after adoptive transfer of 45 million A-LAK cells, an A-LAK cell/tumor cell ratio higher than 1:1 in most metastases was observed. Surprisingly, approximately 5% of the lung metastases seemed totally resistant to infiltration even though neighboring metastases were highly infiltrated. While substantial infiltration of lung metastases was seen after i.v. injection, significant infiltration of liver metastases was seen only after intraportal injection of the A-LAK cells indicating impaired traffic of intravenous injected A-LAK cells through the lung capillaries. These results present direct evidence that A-LAK cells, upon a proper route of administration, have the potential to migrate to and heavily infiltrate metastases from murine tumors of different origin.

Animals↗
PubMed1991

[Current therapeutic targeting possibilities in leukemia].

Investigations on the configuration of immunoglobulin (Ig) and T-cell receptor (TCR) genes have become more and more widespread. Through these methods it is possible to identify malignant clones, which by a transforming event have been blocked in further differentiation but continued to proliferate. Such clonal expansions can be verified by the Southern Blotting procedure as differences in molecular weight between normal and rearranged DNA fragments. In the lymphatic disorders it is possible to assign the malignant clone to B cell lineage by rearrangement in the immunoglobulin light chain gene, while heavy chain and T-cell receptor genes do not show consistency in lineage restriction. In a study on AML patients with solitary expression of the T-cell marker CD7 we have identified a similarity in TCR beta and delta gene configurations, indicating a correlation between etiology and genetic pattern. Such observations can contribute to an elucidation of the malignant blood-diseases and by that a better choice in therapy.

Antigens, Differentiation↗
PubMed1990

Comparison between 125IUdR and 51Cr as cell labels in investigations of tumor cell migration.

YAC-1 tumor cells double-labeled with Na2[51Cr]O4 [51Cr] and [125I]iododeoxyuridine [125IUdR] were injected intravenously into Balb/c mice in order to investigate their migration and fate 0-4 h after the injection. Whereas the clearance of tumor cells from the lung tissue was similar as judged with both labels, the kinetics of isotope uptake in the liver were strikingly different. Thus, retention of 51Cr in the liver was very high compared to a much lower and only transient retention of 125I. A higher retention of non-tumor cell-associated 51Cr was also observed in most other organs, resulting in overestimation of the number of viable tumor cells in these organs. Moreover, a marked spontaneous release (greater than 10% after 12 h) makes 51Cr less suitable as a cell label than 125IUdR. On the other hand, we found that the release of 125I from dead cells in vivo depends at least partially on host factors such as macrophages. Consequently, caution must be exerted when tumor cell migration is investigated in animals treated with drugs that might affect the reticuloendothelial system. We conclude that 125IUdR is superior to 51Cr as a cell label for investigation of tumor cell migration in vivo, even though some doubt about the reliability of the number of tumor cells in liver and carcass, predicted by this radiolabel, still remains.

Animals↗
PubMed1990

Effect of psychological intervention in the form of relaxation and guided imagery on cellular immune function in normal healthy subjects. An overview.

The present study measured the effects of relaxation and guided imagery on cellular immune function. During a period of 10 days 10 healthy subjects were given one 1-hour relaxation procedure and one combined relaxation and guided imagery procedure, instructing the subjects to imagine their immune system becoming very effective. Even though no major changes in the composition of the major mononuclear leukocyte subsets could be demonstrated a significant increase in natural killer function was demonstrated. These data suggest that relaxation and guided imagery might have a beneficial effect on the immune defense and could form the basis of further studies on psychological intervention and immunological status.

Adult↗
PubMed1989

Whole blood assay for NK activity in splenectomized and non-splenectomized hairy cell leukemia patients during IFN-alpha-2b treatment.

Natural killer cell (NK) activity in peripheral blood (PB) was followed longitudinally for up to 2 yr after initiation of low-dose IFN-alpha-2b therapy in nine hairy cell leukemia (HCL) patients. A whole blood NK (WB-NK) assay was employed in order to measure the NK activity per unit blood. The pretreatment WB-NK activity was consistently low, indicating that the patients' total NK activity in PB is decreased. Striking differences in WB-NK activity were observed between splenectomized and non-splenectomized patients, whereas no consistent patterns were found when using the conventional NK assay. Thus the WB-NK activity of splenectomized patients showed an immediate increase after initiation of treatment, while the activity in non-splenectomized patients decreased and remained low during the first 3-6 months. Subsequently, after reduction in spleen size, the WB-NK activity began to increase. In splenectomized patients, a second rise in WB-NK was observed after 3-6 months of therapy, coinciding with the normalisation of the peripheral blood counts. In both groups of patients incubation with IFN in vitro induced a rise in NK activity before start of treatment, which was abrogated promptly after initiation of therapy, indicating a maximal in vivo boosting of the NK cells. These differences observed indicate that the response of splenectomized and non-splenectomized HCL patients to IFN treatment should be evaluated separately.

Cytotoxicity, Immunologic↗