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Biomedical subjects

K Nilsson

Publications and source records attributed to K Nilsson.

At least 145 records · Page 8Linked to original sources
PubMed1994

Activity of cyclosporins as resistance modifiers in primary cultures of human haematological and solid tumours.

The semiautomated fluorimetric microculture cytotoxicity assay (FMCA) was used for evaluation of the ability of cyclosporin A (CsA) and its novel non-immunosuppressive derivative SDZ PSC 833 (PSC) to modify the response to doxorubicin or vincristine in vitro in different haematological and solid human tumour types. Primary cultures of 322 tumour samples were analysed. Both cyclosporins showed resistance-modifying activity in all haematological tumours tested, and in solid tumours activity was observed in ovarian carcinoma and childhood tumours. Little or no effect was found in the remaining tumour types, including breast, renal and adrenal cortical carcinomas and adult sarcomas. In most of the responsive cases the interaction between the modifier and the cytotoxic drug was synergistic. There was a tendency to higher activity in samples from previously treated patients, and an inverse relationship between degree of cytotoxic drug resistance and resistance-modifying activity was noted. No difference in potency between CsA and PSC could be discerned. The results indicate differential in vitro resistance-modifying activity of the cyclosporins depending on tumour type. The results also suggest that treatment with resistance modifiers should be considered also for primary therapy of drug-sensitive tumours. Drug resistance assays such as the FMCA may become useful in preclinical evaluation of resistance modifiers.

Antineoplastic Agents↗
PubMed1994

Plasma homocysteine in relation to serum cobalamin and blood folate in a psychogeriatric population.

Plasma homocysteine, serum cobalamin and blood folate were analysed in 296 consecutive patients referred to a psychogeriatric department for diagnosis of mental disease. Plasma homocysteine correlated with positive significance with age and serum creatinine, and with negative significance with serum cobalamin and blood folate. Approximately 35-40% of the patients with low serum cobalamin (< 150 pmol l-1) or low blood folates (< 150 nmol l-1) exhibited normal values of plasma homocysteine (< 19.9 mumol l-1). Possibly, these patients do not have a deficiency of the vitamins in the tissue. At least 7.5% of the patients with serum cobalamin levels (> 150 pmol l-1) showed an inexplicably increased level of plasma homocysteine. These patients might have a deficiency of tissue cobalamin despite the normal serum cobalamin levels. The effect of cobalamin supplementation for 7-10 days on plasma homocysteine was tested in 62 patients with different levels of serum cobalamins. We found the most pronounced decrease of plasma homocysteine in the patients with lowest serum cobalamin levels and in the patients with highest plasma homocysteine, indicating that the percentage decrease of the initial concentration of plasma homocysteine could reflect the degree of cobalamin deficiency. Folate supplementation for 7-10 days reduced plasma homocysteine not only in patients with folate deficiency but also in those with a normal folate status, and even in patients with cobalamin deficiency. The latter patients further reduced their plasma homocysteine after additional cobalamin treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1994

Phenotypic characterization of the human mast-cell line HMC-1.

The cell line HMC-1, derived from a patient with mast cell leukaemia, is the only established cell line exhibiting a phenotype similar to that of human mast cells. This paper reports on a detailed characterization of the expression of a panel of markers for various types of immature and mature haematopoietic cells in the HMC-1. We also studied the potential of HMC-1 to differentiate upon treatment with conditioned media from the human T-cell line Mo, retinoic acid or DMSO. HMC-1 was found to express several mast cell-related markers. A high expression of Kit, the receptor for stem-cell factor, was detected. The majority of the cells were stained with a MoAb against the mast cell-specific serine protease tryptase. Of particular interest was the finding that beta-tryptase mRNA, but not alpha-tryptase mRNA, was expressed in HMC-1. Using enzyme-histochemistry we were able to show that the beta-tryptase was enzymatically active, indicating that tryptase can form active homotetramers. Both heparin and chondroitin sulfate were found to be present in approximately equal amounts. HMC-1 lacked surface expression of the high-affinity IgE receptor, which was confirmed by the absence of mRNA of the alpha- and beta-chains of the IgE-receptor complex. However, a strong expression of the gamma-chain of the IgE-receptor complex was detected. A positive staining of the monocyte/macrophage marker CD68 was obtained, as well as a strong hybridization signal for the eosinophilic/basophilic-related differentiation marker the Charcot-Leyden crystal. Treatment of HMC-1 with conditioned media from the human T-cell line Mo, retinoic acid or DMSO induced only moderate changes in the surface or intracellular expression of the studied markers. The agents tested neither induced any of the monocyte/granulocyte markers examined, nor expression of the Fc epsilon RI alpha-chain.

Amino Acid Sequence↗
PubMed1994

Early postoperative lipid administration after neonatal surgery.

The ability of neonates to eliminate and utilize lipid emulsions after surgery was investigated in 12 patients. All were subjected to major surgery within 29 h of birth. All neonates were given 10% glucose iv intraoperatively. Six patients continued with 10% glucose iv for 24 h postoperatively and 6 patients received a combination of 5% glucose and soy bean emulsion (Intralipid 20%). Both regimes provided equal amounts of fluid and energy. Blood glucose, lactate, triglycerides, free fatty acids, fractions of fatty acids in triglycerides, 3-hydroxybutyrate and arterial blood gases were measured at predetermined intervals throughout this period. Administration of a lipid emulsion early after neonatal surgery was well tolerated and utilized, with some latency. Concentrations of triglycerides, free fatty acids and 3-hydroxybutyrate were higher in the lipid group, but no accumulation of these substances was found. Palmitinic and linoleic acid were also higher in the lipid group.

Fat Emulsions, Intravenous↗
PubMed1994

Ectopic expression of myc or myn down-regulates immunoglobulin transcription.

Co-transfection of expression vectors for c-myc or myn down-regulated the expression from a reporter plasmid containing the chloramphenicol-acetyl-transferase (CAT) gene, under the control of an immunoglobulin kappa promoter and the immunoglobulin heavy-chain enhancer. The effect was dose-dependent and an additive effect was seen when both expression vectors were transfected simultaneously. Deletion mutants lacking the leucine zipper region of c-myc were unable to down-regulate the transcription from the reporter construct. Reporter genes where the immunoglobulin enhancer had been exchanged with a SV40 enhancer or an immunoglobulin minimal enhancer were still down-regulated by a cotransfection with c-myc expression vectors. A minimal promoter containing an octamer motif responded to myc expression while a minimal promoter containing a SP1 motif did not. No direct interactions between myc, myn and Oct proteins could be detected either by band-shift analysis, or by co-translation in vitro followed by precipitation with SP6 kappa promoter bound to magnetic carriers. Furthermore, B cells from mice transgenic for myc showed aberrant expression of transcription factors.

Animals↗
PubMed1994

Human cell lines U-937, THP-1 and Mono Mac 6 represent relatively immature cells of the monocyte-macrophage cell lineage.

Three human monocytic cell lines, U-937, THP-1 and Mono Mac 6 have, because of their morphology and staining properties, been classed as cell lines frozen in a window of the monocyte differentiation lineage corresponding to monoblasts and/or immature monocytes. These cell lines were analyzed for expression of a panel of hematopoietic differentiation markers by Northern blot analysis. They were all found to express one or several biochemical markers characteristic of immature cells in monocytic development, including myeloperoxidase, N-elastase, cathepsin G, myeloblastin, and azurocidin. Normal peripheral blood monocytes did not express these markers. Moreover, several markers expressed at high levels in mature monocytes, such as lysozyme, CD14, MHC class II and alpha-1 antitrypsin were either not expressed or were expressed only at low levels in the three cell lines analyzed. These results show that arrested differentiation at a relatively early stage of monoblast development is a common denominator for these human monocytic cell lines. Thus, transforming mutations acting at such an immature differentiation stage may frequently lead to neoplastic transformation, whereas similar mutations occurring at a more mature differentiation stage never give rise to any leukemias due to the loss of proliferative potential in committed cells.

Adult↗
PubMed1994

Epstein-Barr virus (EBV) can immortalize B-cll cells activated by cytokines.

B-type of chronic lymphocytic leukemia (B-CLL) cells are inert to the potent transforming action of Epstein-Barr virus (EBV). The mitogenic action of Staphylococcus aureus Cowan I (SAC), MP6-thioredoxin, and interleukin 2 (IL-2), agents previously shown to induce proliferation in normal as well as in B-CLL cells, lifted this block, and EBV-positive cell lines could be established. It was not possible to establish cell lines of leukemic origin from cultures that were incubated with EBV alone or cytokine mix alone. CLL-cells infected with EBV only, expressed the viral nuclear antigen complex (EBNA), but not the viral latent membrane protein (LMP). They were not activated as measured by cell size and 3H-thymidine incorporation. In contrast, cells incubated with EBV and cytokine mix expressed both EBNA and LMP in parallel with enlargement and increased 3H-thymidine incorporation. These results emphasize that LMP expression is a prerequisite for growth transformation and immortalization and that cytokine activation signals are required for its expression in B-CLLs. Cells incubated with SAC/MP6-thioredoxin/IL-2 did not express any of the viral antigens, but were activated with regard to the mentioned parameters. Nine cell lines were established from six patients. From each of the three patients, we obtained 'twin'-pair lines: one corresponding to the malignant cell and the other to a normal B-lymphoblastoid cell. Thus, malignant and normal B-cell counterparts, from the very same donor, are at hand for comparative studies. The cell lines have been carried out for more than 12 months in culture. We conclude that B-CLL that are refractory to EBV-transformation can be rendered susceptible through in vitro cytokine activation.

Antigens, CD↗
PubMed1994

TNF-alpha and IL-6 induce differentiation in the human basophilic leukaemia cell line KU812.

The basophilic leukaemia cell line KU812 can be induced to differentiate into basophil-like cells in vitro when exposed to supernatant from the Mo T-cell line. KU812 cells express affinity receptors for IgE, produce histamine and tryptase and have the capacity for IgE-mediated histamine release. In this study we have examined the cytokines, produced by the Mo cell line, which are responsible for the observed differentiation-inducing effect in the KU812 cell line. It was shown that interleukin-6 (IL-6) and tumour necrosis factor-alpha (TNF-alpha) induced differentiation in the KU812 cells and that these cytokines were responsible for the differentiation-inducing effect of the Mo supernatant. Other cytokines tested, IL-1 beta, IL-2, IL-4, IL-5, IL-8, granulocyte-macrophage colony-stimulating factor (GM-CSF) and nerve growth factor (NGF) were without effect on the KU812 cells. KU812 was also shown to express receptors for both TNF-alpha and IL-6 after 3 days cultivation with conditioned media from the Mo T-cell line. Untreated cells showed no detectable levels of TNF-alpha or IL-6 receptors indicating induction of these receptors during differentiation. Spontaneous differentiation was shown to occur under serum-free conditions which may be the result of endogenous IL-6 production through an autocrine loop. The activity of TNF-alpha and IL-6 could be blocked by specific monoclonal antibodies (mAb) to the respective cytokine.

Basophils↗
PubMed1994

Expression of mad, mxi1, max and c-myc during induced differentiation of hematopoietic cells: opposite regulation of mad and c-myc.

The Myc proto-oncoprotein family is considered to play an important role in the control of cell growth and differentiation. It appears that the interaction of Myc with its heterodimeric partner Max is essential for Myc function. Recently two other partners of Max, called Mad and Mxi1, have been identified. In an effort to gain insight into the network of these four proteins we have started to analyse the expression of the c-myc, max, mad and mxi1 genes at the mRNA level during hematopoietic cell growth and differentiation. In the human myeloid cell lines U-937, HL-60 and ML-1 c-myc expression was down-regulated as shown previously after induction of differentiation, whereas the expression of max was only slightly affected. In contrast to these two genes the expression of mad was induced upon differentiation in the three cell lines by TPA, retinoic acid, vitamin D3, dimethyl sulfoxide, and interferon-gamma and remained elevated for at least 3 days. A kinetic analysis showed that the induction of mad in U-937 in response to TPA was rapid (15 min) and at least in part transcriptional, reminiscent of immediate early genes. The expression of mxi1 was induced in U-937 by some inducers but not in HL-60 or ML-1. Its induction occurred slowly, peaking around 48 h. These analysis thus suggest that the expression of mad and c-myc is inversely regulated during induced hematopoietic differentiation.

Cell Differentiation↗
PubMed1994

Inactivation of tumor suppressor genes, p53 and Rb1, in plasma cell dyscrasias.

The role of loss or inactivation of the retinoblastoma (Rb1) and p53 tumor suppressor genes in the pathogenesis of various human malignancies has been well established, yet little is known regarding plasma cell dyscrasias. In the present study, the loss of Rb1 protein expression, and the presence of Rb1 gene rearrangements as well as the presence of p53 somatic mutations (exons 5 through 9) were investigated in a panel of plasma cell dyscrasias, including 15 monoclonal gammopathies of undetermined significance (MGUS), 63 multiple myelomas (MM), and 18 plasma cell leukemias (PCL). In the same panel of cases, we established the frequency of ras oncogene mutations, the main genetic lesion associated with MM. We report that loss of Rb1 protein and p53 mutations are detectable in 34.7 and 9.8% of MM and PCL primary cases; no lesion was found in MGUS. In advanced stage MM, and PCL cases, Rb1 and p53 inactivation, as well as ras mutations were detected. Our findings show that Rb1 and p53 inactivation are associated with aggressive plasma cell dyscrasias, suggesting a role for these lesions in tumor progression rather than initiation.

Base Sequence↗
PubMed1993

Functional antagonism between vitamin D3 and retinoic acid in the regulation of CD14 and CD23 expression during monocytic differentiation of U-937 cells.

1,25 alpha-Dihydroxicholecalciferol (VitD3) and retinoic acid (RA) are important regulators of the proliferation and differentiation of several cell types. This paper describes how the expression of the monocyte-macrophage Ag, CD14, and the low affinity Fc receptor for IgE, CD23, were inversely regulated during VitD3- and RA-induced monocytic differentiation of human U-937 monoblasts. PMA induced the expression of both CD14 and CD23 mRNA and protein. Exposure to VitD3 rapidly induced the de novo expression of CD14 mRNA and protein. The addition of cycloheximide completely blocked the VitD3 induction of CD14 mRNA expression, indicating that the induction was dependent on ongoing protein synthesis. While inducing CD14 expression, VitD3 concomitantly suppressed the basal, PMA-, and RA-inducible CD23 expression in a dose-dependent manner. In contrast, U-937 cells induced by RA strongly increased their expression of CD23 mRNA and protein, whereas they completely lacked detectable CD14 cell surface or mRNA expression. Furthermore, the VitD3- and the PMA-induced CD14 expression was inhibited as a temporal consequence of the RA-induced differentiation. The results suggest that there exists a functional antagonism between VitD3 and RA that may have important implications for the regulation of certain immune and inflammatory responses through their inverse effects on CD14 and CD23 gene expression.

Antigens, CD↗
PubMed1993

The effect of storage on ice and various freezing treatments on enzyme leakage in muscle tissue of rainbow trout (Oncorhynchus mykiss).

In order to study the biochemical changes in fish muscle during ice storage and freezing-thawing processes, the activities of certain marker enzymes in the cell interstitial fluid from muscle tissue of rainbow trout (Oncorhynchus mykiss) were measured. The enzymes analysed were: lysosomal alpha-glucosidase (E.C. 3.2.1.20), beta-N-glucosaminidase (E.C. 3.2.1.30) and acid phosphatase (E.C. 3.1.3.2). The activity in centrifuged tissue fluid (CTF) was compared with the activity in total homogenate. When ice storage was varied between 3 and 14 days, it did not affect enzyme leakage into the CTF significantly. However, there was a distinct difference between fresh fish and fish iced even for only 1 day, which gave increased leakage of marker enzymes. When the ice-stored samples were subject to a freezing-thawing cycle they showed a marked increase in enzyme activity in the press juice. When the freezing process was varied so as to achieve different freezing rates, the slowest freezing rate caused the highest enzyme leakage.

Acetylglucosaminidase↗
PubMed1993

Downregulation of tenascin expression by glucocorticoids in bone marrow stromal cells and in fibroblasts.

Tenascin, a predominantly mesenchymal extracellular matrix (ECM) glycoprotein has a rather restricted tissue distribution, but until now factors that inhibit its expression have not been identified. Glucocorticoids are known to be beneficial for establishment of myelopoiesis in long-term bone marrow cultures. Tenascin was found to be expressed in the bone marrow, and glucocorticoids were found to affect bone marrow tenascin expression. Both tenascin mRNAs and the mRNA of another ECM protein, laminin B1 chain, were drastically downregulated by glucocorticoids during initiation of bone marrow cultures. However, in already established long-term cultures glucocorticoids did not affect laminin B1 chain mRNA levels although tenascin mRNAs continued to be downregulated. Studies with a stromal cell line (MC3T3-G2/PA6) and fibroblasts (3T3) suggested that glucocorticoids act directly on the stromal cells that produce tenascin. In 3T3 cells this downregulation occurred within 12 h of glucocorticoid-treatment, suggesting that glucocorticoids acted through cis regulatory elements of the tenascin gene. We suggest that glucocorticoids in part regulate hematopoiesis by modifying the ECM. Furthermore, downregulation of tenascin expression by glucocorticoids may in part explain the restricted tissue distribution of tenascin in other tissues.

3T3 Cells↗
PubMed1993

Effects of TPA on mitosis of V79 Chinese hamster cells. Reduced precision of chromosome distribution and modification of entrance into and exit out of mitosis.

Protein kinase C (PKC) was activated in V79 Chinese hamster cells with 10 nM 12-O-tetradecanoylphorbol-13-acetate (TPA). Within 30 min soluble activity decreased concomitant with a 10-fold increase of particulate activity. The latter was still elevated after 3 h but was back to control levels after 24 h of treatment; by then soluble activity was lost. The frequency of mitotic cells with signs of abnormal spindle function increased within 15 min and reached a plateau after 45-60 min which lasted throughout the 4 h treatment. The c-mitotic effect was delayed and significantly lower when 10 nM TPA was combined with 50 microM of the protein kinase inhibitor H7. The frequency of disturbed mitotic cells decreased after 24 h of treatment but remained significantly higher than in non-treated cells. Change of medium and addition of new TPA caused a slight but significant further increase. It is suggested that PKC takes part in eliciting the c-mitotic effect of TPA. However, the sustained effect coincident with down-regulation points to significant alterations of the level or the activity of an as yet unidentified ultimate elicitor. TPA also caused a transient block in the G2 phase which was ameliorated by H7 and which could not be detected at all in TPA-pretreated cells (24 h) given new TPA. This suggests that PKC takes part in eliciting the G2/M block as well but the mechanism is different from the one(s) behind the c-mitotic effect. V79 cells were found to exit from mitosis in the presence of 0.2 microgram/ml of colcemid but TPA-pretreated cells showed a decreased exit rate. There was no sign of hampered exit among cells going into mitosis soon after the G2 block was reversed, which implies that the spontaneous reversal of the block does not involve rapid down-regulation of PKC.

Animals↗
PubMed1993

Expression of a mast cell tryptase in the human monocytic cell lines U-937 and Mono Mac 6.

Expression of a mast cell tryptase mRNA was detected in two human monocytic cell lines, the U-937 and the Mono Mac 6, and in normal human peripheral blood (PB) monocytes. In the U-937 cell line but not in normal PB monocytes, the tryptase expression was upregulated 3-50 fold following phorbol ester (PMA)-induced differentiation, but no such induction was seen after retinoic acid, interferon-gamma or vitamin D3 exposure. The tryptases expressed in PMA-induced and non-induced U-937 and in Mono Mac 6 were characterized by PCR amplification and nucleotide sequence analysis. The U-937 cell line was found to express a tryptase identical to one of the previously cloned mast-cell beta tryptases (Tryptase I), and the tryptase expressed in Mono Mac 6 was found to be nearly identical to the previously cloned alpha tryptase. By northern blot analysis with oligonucleotide probes specific for the alpha and beta tryptases both cell lines were found to express only one type of tryptase. Densitometric quantifications of tryptase mRNA levels, in the two cell lines, showed approximately 80 times higher mRNA levels in Mono Mac 6 compared to non-induced U-937. Immunohistochemical staining for tryptase showed a marked heterogeneity in the Mono Mac 6 cell line. Only one out of 10 cells were positive for the protein but the levels in these cells were very high, equivalent, or even higher than the levels seen in the human mast cell line HMC-1. This shows that the expression of a single tryptase, in this case the alpha tryptase, is sufficient for the production of a stable protein and probably also a stable proteolytically active tetramer. The family of human mast-cell tryptases has been considered to represent a class of proteases specifically expressed in mast cells and basophilic leucocytes. The expression of tryptases in two monocytic cell lines and in normal PB monocytes indicate that in humans, the lineage specificity of these serine proteases is less restricted than earlier expected. The cloning of a full length cDNA for the murine counterpart to the human mast cell tryptases, the MMCP-6, is presented. No expression of the MMCP-6 was detected in a panel of mouse monocyte or macrophage cell lines indicating a species difference in the lineage specificity of the 'mast cell tryptases'.

Animals↗
PubMed1993

Interleukin-4 (IL-4) enhances homotypic adhesion of activated B-chronic lymphocytic leukaemia (B-CLL) cells via a selective up-regulation of CD54.

It is well established that cell-to-cell contact modifies cytokine signalling but little is known on the role of homotypic cell adhesion for proliferation and differentiation of B cells. Homotypic adhesion involves mainly the interaction between the adhesion molecules Leukocyte Function Antigen-1 (LFA-1) and its ligand CD54 (ICAM-1). A well-characterized B-chronic lymphocytic leukaemia (B-CLL) clone (I-83) was used as a source of monoclonal B cells inducible to DNA synthesis and differentiation by using 12-O-tetradecanoyl-phorbol-13-acetate (TPA) in combination with interleukin-4 (IL-4) and thioredoxin (Trx)-containing supernatant from a T-cell hybridoma (BSF-MP6). This paper shows that IL-4 alone was able to induce aggregation of B-CLL cells and to strongly enhance TPA+BSF-MP6-induced aggregation. The results from studying the expression of CD11a and CD18, the two subunits of LFA-1, and CD54 during stimulated DNA synthesis and differentiation suggest that IL-4-induced, or enhanced, aggregation was mainly mediated by a selective up-regulation of CD54. It was further demonstrated by antibody blockade to either CD11a, CD18 or CD54 that aggregation could be inhibited without affecting induced DNA synthesis or differentiation.

Antibodies↗
PubMed1993

The effects of prophylactic dixyrazine on postoperative vomiting after two different anaesthetic methods for squint surgery in children.

The incidence of postoperative vomiting after squint surgery was studied for two anaesthetic techniques with and without prophylactic dixyrazine. After induction, anaesthesia was maintained with either fentanyl/pancuronium/nitrous oxide or halothane/nitrous oxide in two randomly selected groups of 58 children each. Half of the children in each group were randomly allocated to receive dixyrazine 0.25 mg kg-1 i.v. after surgery had been completed but before reversal of muscle relaxants or termination of anaesthesia. With prophylactic dixyrazine the incidence of postoperative vomiting was significantly reduced from 69% (20/29) to 21% (6/29) in the fentanyl group and from 45% (13/29) to 10% (3/29) in the halothane group. Without prophylactic dixyrazine, 20 of 29 children in the fentanyl group vomited compared to 13 of 29 in the halothane group (n.s.). Thus, prophylactic dixyrazine reduced the incidence of vomiting in children given either opioid or halothane anaesthesia for squint surgery. In comparable groups avoidance of opioid anaesthetic technique and use of prophylactic dixyrazine resulted in a greatly reduced incidence of vomiting.

Adolescent↗