Biomedical subjects

L C Andersson

Publications and source records attributed to L C Andersson.

At least 127 records · Page 7Linked to original sources

PubMed1986

Role of G-proteins in T cell activation: non-hydrolysable GTP analogues induce early ornithine decarboxylase activity in human T lymphocytes.

Rapid activation of ornithine decarboxylase is one of the earliest recognized events during induction of a mitogenic response in human T lymphocytes. Here we show that the non-hydrolysable GTP analogues guanine-5-(gamma-thio)trisphosphate and guanylyl-5-imidodiphosphate, introduced into human T cells by means of a transient membrane permeabilization technique, can replace an external mitogenic ligand, such as concanavalin A, in inducing early ornithine decarboxylase activity. Neomycin inhibits this rapid activation at concentrations known to bind to phosphoinositides. One of the two compounds formed in polyphosphoinositide breakdown, inositol-1,4,5-trisphosphate, also induces ornithine decarboxylase activity. The other, diacylglycerol, apparently does not, since the phorbol ester, tetradecanoyl phorbol acetate, which is thought to mimic the action of diacylglycerols, does not alter basal ornithine decarboxylase activity in T cells until several hours after administration. These findings indicate that guanine nucleotide-binding regulatory (G-) protein(s) participates in the transduction of the mitogenic signal. The intracellular target system for this G-protein may include phosphoinositide breakdown and generation of inositoltrisphosphate, which might be involved in the early activation of ornithine decarboxylase.

Cell Membrane Permeability↗

PubMed1986

myo-Inositol reverses Li+-induced inhibition of phosphoinositide turnover and ornithine decarboxylase induction during early lymphocyte activation.

One of the earliest detectable responses by T lymphocytes in vitro to various mitogenic ligands is the rapid induction of ornithine decarboxylase (ODC) activity (Scott et al., Eur. J. Immunol. 1985. 15: 783). This early activation is measurable within minutes after the addition of the mitogen. The T cell mitogen concanavalin A also induces rapid breakdown of phosphoinositides in T lymphocytes. The inositol phosphates formed are recycled and used in synthesis of new phosphoinositides. Li+ interrupts this cycle by inhibiting the enzyme inositol-1-phosphatase, which produces the inositol needed for phosphoinositide synthesis. Here we report that when human blood lymphocytes are kept in an inositol-deficient medium for 30 min in the presence of 1 mM Li+, the cells become unable to respond to mitogens by inositide breakdown and rapid induction of ODC activity. Addition of 1 mM myo-inositol restores the inducibility of these responses within a few minutes. These findings represent a novel aspect of the activation of resting lymphocytes and implies a new role for the inositol turnover during signal transduction.

Chlorides↗

PubMed1986

Development of a neural phenotype in differentiating ganglion cell-derived human neuroblastoma cells.

Human neuroblastoma cells (clone SHSY-5Y) induced to differentiate by 12-O-tetradecanoylphorbol-13-acetate (TPA) are shown to possess properties characteristic of mature ganglion cells. Elevation of the external K+ concentration, exposure to Ca2+ ionophore A23187, and acetylcholine all stimulate the release of preloaded 3H-noradrenaline in the presence but not in the absence of added Ca2+. Acetylcholine causes a fall in the 86Rb+ or 14C-TPMP equilibrium potential across the plasma membrane and stimulates 86Rb+ efflux. These responses are prevented by atropine. Acetylcholine and muscarine but not nicotine stimulate an increase in 45Ca2+ influx, an effect blocked by atropine. None of these responses have been observed in nondifferentiating cells. Muscarinic receptors, however, as measured by the binding of tritiated quinuclidinyl benzilate (3H-QNB), were present to a similar extent in control and differentiated cells. Both cell types also exhibit an accelerated release of Ca2+ in response to acetylcholine, but the control cells were at least 1 order of magnitude more sensitive to the agonist.

Acetylcholine↗

PubMed1986

Presence of apocrine epithelial antigen (AEA) in type II pneumocytes and in hyaline membranes of neonatal RDS.

We have investigated the distribution of an apocrine membrane antigen (AEA) in pulmonary tissue using a rabbit antiserum raised against fat globule glycoproteins isolated from human milk. In indirect immunostaining (PAP, IF) of sections from normal lung tissue, the membranes facing the alveolar lumen of cells corresponding to the type II pneumocytes in the alveolar walls were decorated. The selective distribution of AEA to the membranes of type II pneumocytes was confirmed in double immunostaining by identification of these cells with rat antibodies against surfactant apoprotein. In fetal lung tissue, the AEA antigen was detected by the 9th week of gestation. In lung samples from newborns which had died of respiratory distress syndrome (RDS) the intra-alveolar hyaline membranes stained for the AEA antigen. SDS-PAGE of the immunoprecipitate obtained with anti-AEA serum from radiolabelled glycoprotein fraction of normal lung tissue revealed a single band of 79,000 dalton apparent molecular weight. These findings indicate that the AEA constitutes a membrane marker of the type II pneumocytes and might be involved in the secretory process of surfactant. Immunohistological evidence for the presence of AEA in the hyaline membranes of neonatal RDS is also presented.

Antigens↗

PubMed1986

Urinary catheter structure and testing methods in relation to tissue toxicity.

Eluates from 56 latex urinary catheters from seven manufacturers were divided into three categories according to covering material (siliconized, silicone elastomer coated and teflon coated) and tested for tissue toxicity by means of cell cultures based on the inhibition of DNA synthesis. The silicone elastomer coated catheters showed the lowest toxicity. Only 4 of 13 such catheters gave unacceptable toxic values, whereas half of the siliconized catheters were abandoned as toxic. Teflon and elastomer coatings had the best protective properties against toxic substances leaching from the catheter core. The surface contour of the catheters estimated by scanning electron microscopy (SEM) did not correlate with toxicity, whereas the cracks seen on the catheters did correlate with toxicity. The simple in vivo test methods used by the manufactures turned out to be insensitive to tissue toxicity testing of urinary catheters. The method used in this study was the most reliable for assessing the safety of latex urinary catheters. Thus manufacturers using multiple and in vitro cell culture tests had products of better quality than those using only a single test or simple in vivo tests.

Cell Survival↗

PubMed1986

A lipophilic iron chelator induces an enhanced proliferation of human erythroleukaemia (HEL) cells.

Iron metabolism is important for proliferation, but in erythroid cells it is also required for haem synthesis. In erythroleukaemia cells, there is both a continuous proliferation and a synthesis of haem, and these cell lines are therefore especially interesting for studies on iron metabolism. Iron can be efficiently delivered intracellularly by certain chelators which bypass the transferrin-receptor-mediated pathway of iron uptake. We now show that the human erythroleukaemia cell line, HEL, displays a greatly enhanced cell proliferation when cultured in the presence of the lipophilic iron chelator, ferric pyridoxal isonicotinoyl hydrazone. The proliferation is not accompanied by an increase in haemoglobin synthesis. The response is apparently not typical for all erythroleukaemia cells, since a similar cell line, K 562, did not respond to the chelator by enhanced proliferation.

Cell Cycle↗

PubMed1986

Lectin-binding sites in normal, hyperplastic, adenomatous and carcinomatous human colorectal mucosa.

The carbohydrate structures of cellular glycoconjugates in normal, hyperplastic, adenomatous and carcinomatous human colorectal mucosa were analysed with six fluorescein isothiocyanate-conjugated lectins. In normal, hyperplastic and adenomatous colorectal mucosa showing mild or moderate dysplasia Concanavalin A (Con A), Lens culinaris (LCA), and wheat germ (WGA) agglutinins stained goblet cell glycoconjugates (actual mucin goblet itself) while peanut (PNA), Vicia villosa (VVA), and Griffonia simplicifolia-II (GSA-II) agglutinins showed a supranuclear staining of goblet cell glycoconjugates. After neuraminidase treatment of tissue sections PNA and VVA stained mucin goblets of mature cells in normal mucosa, while less differentiated cells in the lower crypt displayed a supranuclear staining with VVA. The mucin goblets in adenomatous mucosa with mild or moderate dysplasia did not stain with PNA and VVA, neither before nor after neuraminidase treatment. Areas of in situ cancer in adenomas and carcinomas displayed a strong and direct binding of Con A, LCA, WGA and PNA in an apical linear distribution, while the binding of VVA and GSA-II was heterogeneous. We conclude that there are alterations in the carbohydrate structures of cellular glycoconjugates, which can be related to goblet cell differentiation in normal colorectal mucosa and to the degree of dysplasia in adenomas. Heterogeneous and incompletely glycosylated glycoconjugates appear to be synthesized by the majority of colorectal carcinomas.

Adenoma↗

PubMed1986

Toxic catheters and diminished urethral blood circulation in the induction of urethral strictures.

Local effects of indwelling urinary catheters are poorly characterized. Latex catheter brands of various degrees of tissue toxicity were implanted into the urethra of 27 male piglets. The systemic hemodynamic states varied from normal to hypovolemia, where the circulation changes simulated the extracorporeal perfusion used in open-heart surgery. The urethral epithelial changes caused by the catheters were studied by light ad scanning electron microscopy (SEM). The blood circulation in paraurethral tissue reacted strongly to systemic hemodynamic changes. A reduced local blood flow induced an accumulation of polymorphonuclear leucocytes in the urethral epithelium and subepithelial space in connection with implanted latex urinary catheter strips. This was not seen in normovolemic piglets. Non-toxic wholly silicone control catheter implants did not induce changes. Epithelial cell damage correlated with the tissue toxicity values of implanted catheter strips. In SEM analysis destruction of microvilli and cell membranes was also discovered in connection with a latex catheter brand regarded as non-toxic. The wholly silicone catheters did not cause any detectable changes. The observed cell damage is induced by toxic chemicals dissolving from latex catheters. Local ischemia exacerbates these toxic effects and activates complement cascade. This induces polymorphonuclear granulocyte accumulation in the damaged urethral epithelium leading to demolition and urethral fibrotization. The present findings explain the etiology of the long urethral stricture epidemics seen in open-heart surgery in the early 1980s by showing the interference between indwelling latex catheters and reduced local blood flow.

Animals↗

PubMed1986

B lymphoblastoid cell lines with normal and defective O-glycosylation established from an individual with blood group Tn.

Individuals with the Tn blood group contain terminal serine/threonine-linked N-acetylgalactosamine residues in their blood cells. This is due to lack of UDP-D-galactose: D-N-acetyl galactosamine beta-D-galactosyl transferase from part of their red cells and probably from their leukocytes. We have established B lymphoblastoid cell lines from such an individual by in vitro infection of his lymphocytes with Epstein-Barr virus. The original line contained a mixture of cells reactive and nonreactive with Helix pomatia lectin (Hp). These cells were subcloned after staining with fluorescent Hp by a fluorescence-activated cell sorter (FACS) into homogeneous, phenotypically stable lines of Hp-positive (Hp+) and Hp-negative (Hp-) cells. The molecular differences between the membrane glycoproteins were characterized by carbohydrate-specific surface labeling techniques, Hp affinity chromatography, polyacrylamide slab gel electrophoresis and glycopeptide/oligosaccharide analysis. The major O-glycosidic membrane glycoprotein (GP105) was retained on Hp-Sepharose columns only from Hp+ cells, whereas the common leukocyte antigen (GP160-200) was partially retained on Hp columns from both lines. These proteins were isolated by immune precipitation with monoclonal antibodies and characterized. The results show that the GP105 glycoprotein from Hp+ cells contains terminal N-acetylgalactosamine residues but also more complex oligosaccharides. The common leukocyte antigen showed different electrophoretic mobilities in Hp+ and Hp- cells. UDP-galactose D-N-acetyl galactosamine beta-galactosyl transferase was almost absent in the Hp+ cells. These cell lines are useful for studies on the functional role and regulation of the biosynthesis of O-glycosidic carbohydrates.

B-Lymphocytes↗

PubMed1985

Biosynthesis of the major human red cell sialoglycoprotein, glycophorin A. O-Glycosylation.

The biosynthesis of the major human red cell sialoglycoprotein, glycophorin A, was studied in the erythroleukemia cell line K562 with emphasis on O-glycosylation. The cells were pulse-chase labeled with [35S] methionine, and either directly immune precipitated with anti-glycophorin A antiserum or detergent-solubilized extracts first passed through columns containing the N-acetylgalactosamine-specific lectin from Helix pomatia or the glucose/mannose specific lectin from lentil beans. From the sugar-eluted fractions anti-glycophorin A antiserum was used to identify precursor molecules. After 5 min of labeling the first glycophorin A precursors were seen. The largest had an apparent molecular weight of 37,000, and bound to lentil lectin-Sepharose, but not to H. pomatia lectin-Sepharose. The lentil lectin-reactive glycophorin A molecules increased to Mr = 39,000 during chase and obtained sialic acids after 9 min of chase reflecting terminal N- and O-glycosylation. After 5-6 min of labeling two H. pomatia-interacting glycophorin A precursors with apparent molecular weights of 24,000 and 30,000 were obtained. These did not bind to lentil lectin-Sepharose. During chase also these molecules increased in size to Mr = 39,000. The immune precipitation of all antiglycophorin A-reactive precursor molecules was inhibited by purified red cell glycophorin A. The carboxylic ionophore, monensin, caused the accumulation of incompletely O-glycosylated glycophorin A molecules, which bound to H. pomatia lectin-Sepharose. These were degraded by treatment with endo-beta-N-acetylglucosaminidase H reflecting incomplete processing of the N-glycosidic oligosaccharide.

Cell Line↗

PubMed1985

1-Aminooxy-3-aminopropane, a new and potent inhibitor of polyamine biosynthesis that inhibits ornithine decarboxylase, adenosylmethionine decarboxylase and spermidine synthase.

1-Aminooxy-3-aminopropane was shown to be a potent competitive inhibitor (Ki = 3.2 nM) of homogenous mouse kidney ornithine decarboxylase, a potent irreversible inhibitor (Ki = 50 microM) of homogeneous liver adenosylmethionine decarboxylase and a potent competitive (Ki = 2.3 microM) of homogeneous bovine brain spermidine synthase. It did not inhibit homogeneous bovine brain spermine synthase and it did not serve as a substrate for spermidine synthase. The compound did not inhibit tyrosine aminotransferase, alanine aminotransferase or aspartate aminotransferase, which are pyridoxal phosphate-containing enzymes like ornithine decarboxylase. The inactivation of adenosylmethionine decarboxylase was partially prevented by pyruvate, which is the coenzyme of adenosylmethionine decarboxylase, and by the substrate, adenosylmethionine. 1-Aminooxy-3-aminopropane at 0.5 mM concentration inhibited the growth of HL-60 promyelocytic leukemia cells and this inhibition was prevented by spermidine but not by putrescine.

Adenosylmethionine Decarboxylase↗

PubMed1985

Interaction of Cd2+ with the calmodulin-activated (Ca2+ + Mg2+)-ATPase activity of human erythrocyte ghosts.

Treatment of erythrocyte ghosts with micromolar concentrations of Cd2+ results in a noncompetitive inhibition of the calmodulin-dependent (Ca2+ + Mg2+)-ATPase activity. Higher concentrations of Cd2+ are required for inhibition of the (Ca2+ + Mg2+)-ATPase activity of calmodulin-depleted ghosts. The interaction of Cd2+ is time-dependent with an apparent rate constant around 0.12/min. The inhibition is relieved by addition of EGTA with a rate constant around 0.15/min. If Cd2+ is allowed to interact with calmodulin prior to the association of the protein with the ghosts, the inhibition is mainly competitive. The results suggest that the inhibitory effect caused by Cd2+ is due to an interaction with calmodulin. The slow interaction of Cd2+ suggests that calmodulin bound to the (Ca2+ + Mg2+)-ATPase is inaccessible to Cd2+.

Ca(2+) Mg(2+)-ATPase↗

PubMed1985

A human neuroblastoma cell line with a stable ornithine decarboxylase in vivo and in vitro.

A human neuroblastoma cell line (Paju) grew in 10 mM difluoromethyl-ornithine, which at this concentration normally stops the growth of all mammalian cells. Ornithine decarboxylase from Paju was resistant to inhibition in vitro by difluoromethylornithine, and required 10 microM of the compound for 50% inhibition, whereas ornithine decarboxylase from SH-SY5Y cells (another human neuroblastoma) and from rat liver needed only 0.5 microM difluoromethylornithine. Paju ornithine decarboxylase also exhibited a long half-life (over eight hours) in vivo. The half-life of immunoreactive protein was significantly longer than that of the activity. The long half-life of ornithine decarboxylase in Paju cells leads to its accumulation to a specific activity of 2000 nmol/mg of protein per 30 min during rapid growth (the corresponding activity in SH-SY5Y cells was about 2.5). When partially purified ornithine decarboxylase from Paju cells was incubated with rat liver microsomes it was inactivated with a half-life of 75 min. This inactivation was accompanied by a fall in the amount of immunoreactive protein. In the same inactivating system partially purified SH-SY5Y ornithine decarboxylase had a half-life of 38 min and its half-life in vivo was 50 min. The corresponding values for rat liver ornithine decarboxylase were 45 min and 40 min, respectively. Rat liver microsomes also inactivated rat liver adenosylmethionine decarboxylase. These results suggest that Paju ornithine decarboxylase has an altered molecular conformation, rendering it resistant to (i) difluoromethylornithine and (ii) proteolytic degradation both in vivo and in vitro.

Adenosylmethionine Decarboxylase↗

PubMed1985

Rapid activation of ornithine decarboxylase by mitogenic (but not by nonmitogenic) ligands in human T lymphocytes.

The T cell mitogens, concanavalin A and the monoclonal antibody OKT3, cause a rapid activation of ornithine decarboxylase (ODC) activity in human T lymphocytes, maximal within 10 min of mitogen addition. Nonmitogenic ligands to T cell surface structures do not induce ODC. The enzyme induction is dependent upon an intact mobility of ligand-receptor complex, requires a functioning energy metabolism, but is independent of de novo protein synthesis. The early induction of pre-existing ODC molecules appears to be specifically linked to the initiation of T lymphocyte proliferation.

Cycloheximide↗

PubMed1985

Kinetics of long-term (72 hr) calcium content during mitogen activation of cultured human T lymphocytes.

In vitro stimulation of human blood lymphocytes with mitogen resulted in an increased intracellular content of Ca2+ per unit cell volume. This increase in Ca2+ content of lectin-activated cells reached a maximum after 24 hr of culture and thereafter slowly declined. Brief treatment of cells at 24 hr of culture with the Ca2+ ionophore A23187 in combination with EGTA resulted in a larger release of Ca2+ from cells in mitogen-stimulated cultures than from cells in control cultures. This indicates that the Ca2+ is accumulated intracellularly but is readily exchangeable. At 24 hr of culture the increase in cellular Ca2+ correlated well with the proliferative response as measured by 3H-thymidine incorporation. Ca2+ influx at 24 and 48 hr of culture was markedly enhanced in the mitogenically stimulated cells as compared either to cells cultured for 1 and 72 hr or cells cultured without mitogen.

Biological Transport↗

PubMed1985

Effects of Cd2+ upon Ca2+ fluxes and proliferation in concanavalin A-stimulated lymphocytes.

The mitogenic response of human peripheral blood lymphocytes to the lectin concanavalin A (conA) is inhibited by micromolar concentrations of CdCl2. This inhibition is partially relieved by an increase in the external Ca2+ concentration (from 0.6 to 2.2 mM). The initial rate of conA-induced 45Ca2+ influx is unaltered by CdCl2, although the level of 45Ca2+ accumulation increases. The basal rate of 45Ca2+ entry is not measurably disturbed by CdCl2 (100 microM). The steady-state efflux of 45Ca2+ and the calmodulin-activated (Ca2+ + Mg2+)-ATPase activity of erythrocyte ghosts are inhibited by CdCl2 (10 microM). Thus, the mechanism behind the Cd2+-induced suppression of the mitogenic response to conA is not due to alteration of mitogen-stimulated Ca2+ influx. We suggest that Cd2+ competes with Ca2+ for intracellular Ca2+-binding molecules, such as calmodulin, essential for the induction of cell proliferation.

Biological Transport, Active↗

PubMed1985

Hormonally regulated expression of an apocrine epithelial antigen in the cell membranes of endometrial glands.

We have raised a rabbit antiserum against formalin-treated membrane glycoproteins isolated by lectin affinity chromatography from human milk fat globules. In immunofluorescence staining the antiserum reacts strongly and exclusively with the apical membrane of the glandular epithelial cells in normal endometrium during the proliferative phase. No membrane-bound antigen is seen during the secretory phase but some positively staining material is found in the glandular lumina and a weak cytoplasmic staining is also seen. The antigen is absent in postmenopausal endometrium but is found in abundance in the cell membrane of the glandular epithelium in endometria from postmenopausal women receiving estrogen treatment. The glandular epithelium of hyperestrogenism-induced endometrial hyperplasia is very strongly decorated by the antiserum. Molecular characterization of the antigen by immunoblotting under reducing conditions reveals two polypeptides of 110,000 daltons and 93,000 daltons from normal endometrium during the proliferative phase. A single band of 75,000 daltons, probably representing shed fragment, is seen in secretory endometrium. This hormonally regulated and strictly located protein differs from many other endometrial proteins in that it is estrogen-induced, while others are dependent on progesterone effect, and it constitutes an interesting histochemical marker of endometrial glands.

Antibodies↗

PubMed1985

Toxicity testing of urinary catheters.

The tissue toxicity of 23 urinary catheter batches (6 latex and 2 non-latex brands) was tested in vitro and in vivo. In vitro, a human T-cell leukemia line (JM) was cultured in the presence of different concentrations of eluates made from the catheters. The cytotoxicity of the eluates was assessed from their ability to inhibit DNA synthesis measured by incorporation of 3H-thymidine. In vivo, two methods were used. Strips of catheters were implanted into the rabbit dorsal muscle and pieces of catheters were implanted into the rat peritoneal cavity. After four days, the foreign body reaction, type of inflammation and necrosis were quantified macroscopically and by light microscopy. The results of the in vitro cytotoxicity test were correlated with those of in vivo methods. The rat peritoneal implantation test correlated better with the cell culture test (P less than 0.01) than with the rabbit muscle implantation test (P less than 0.05). Based on the clinical experience of urethral stricture complications caused by urinary catheters, catheters yielding eluate which at 30% dilution inhibited 50% DNA synthesis were regarded as toxic. According to this, the rabbit muscle implantation test was not reliable in testing the tissue toxicity of urinary catheters, while the cell culture test was quantitative and seemed to correlate with both the rat peritoneal implantation test and with the clinical complications observed.

Animals↗