Heterogeneic modulation of malignant behavior in human glioma cells in defined and serum-containing media

Summary Malignant features in three glioma cell lines were studied in four defined media of various complexity. The cell lines D37MG, D54MG, and GaMG were able to grow in monolayer culture in all media examined, and as multicellular tumor spheroids in the two most nutrient-rich media. In the defined media, none of the cell lines were able to migrate in a migration assay on poly-D-lysine-coated plastic surfaces. Flow cytometric analysis of the GaMG cell line demonstrated no medium-dependent selection of subclones of glioma cells in spheroids cultured for 30 d. Morphological diversity of spheroids varied according to the supplementation of the media. The capacity of glioma cells to invade cellular rat brain aggregates was intact in the media examined. However, glioma migration was severely inhibited by the lack of specific serum components. This study demonstrates that glioma growth and invasion was heterogenously preserved in the defined media used. Depending on the assay to be used in the study of glioma cell behavior, the degree of medium supplementation has to be considered.     

Effects of ammonium sulphate application on the chemistry of bulk soil,rhizosphere, fine roots and fine-root distribution in a Picea abies (L.) karst. stand

The effect of ammonium sulphate application on the bulk and rhizosphere soil chemistry, elemental concentration of living fine roots (<2 mm in diameter), amounts of living and dead fine roots, root length density and specific root length density were investigated in a 28 year old Norway spruce stand in SW Sweden. The treatments started in 1988. Core samples of the LFH layer and mineral soil layers were sampled in control (C) and ammonium sulphate (NS) treatment plots in 1988, 1989 and 1990. Soil pH and NO₃-S and SO₄-S, Al, Ca, Mg, Mn and K concentrations were measured for both the bulk soil and rhizosphere soil.The pH-values of the bulk and rhizosphere soil decreased in 1989 and 1990 in NS plots compared to control plots, while the SO₄-S concentration increased. The Ca, Mg and K concentration increased in the NS treatment in almost all layers in the bulk and the rhizosphere soil. Ammonium ions may have replaced these elements in the soil organic matter. The NS treatment reduced Mg concentration in fine roots in all layers in 1990. The Al concentrations in the rhizosphere and bulk soil were higher in NS plots in all layers, except at 0–10 cm depth, both in 1989 and 1990. The Al content of living fine roots was higher in NS plots than C plots but the differences were not significant. The NS addition did not affect the P and K contents of fine roots in any soil layer, but the S concentrations of fine roots were significantly higher in NS plots in 1989 and 1990. The fine root necromass was higher in NS than in C in 1990, in the LFH layer, indicating a gradual decrease in the vitality of the fine roots. It was suggested that the NS treatment resulted in displacement of Mg and K from exchange sites in the LFH layer leading to leaching of these cations to the mineral soil. Further application of ammonium sulphate may damage the fine roots and consequently adversely affect the water and nutrient uptake of root systems.     

Light-induced expression of ipt from Agrobacterium tumefaciens results in cytokinin accumulation and osmotic stress symptoms in transgenic tobacco

Cytokinins are plant growth regulators that induce shoot formation, inhibit senescence and root growth. Experiments with hydroponically grown tobacco plants, however, indicated that exogenously applied cytokinin led to the accumulation of proline and osmotin. These responses were also associated with environmental stress reactions, such as salt stress, in many plant species. To test whether increased endogenous cytokinin accumulation led to NaCl stress symptoms, the gene ipt from Agrobacterium tumefaciens, encoding isopentenyl transferase, was transformed into Nicotiana tabacum cv. SR-1 under the control of the light-inducible rbcS-3A promoter from pea. In high light (300 mol PPFD m^-2 s^-1), ipt mRNA was detected and zeatin/zeatin glucoside levels were 10-fold higher than in control plants or when transformants were grown in low light (30 mol PPFD m^-2 s^-1). High light treatment was accompanied by increased levels of proline and osmotin when compared to low light grown transformed and untransformed control plants. Elevated in planta cytokinin levels induced responses also stimulated by salt stress, suggesting either common or overlapping signaling pathways are initiated independently by cytokinin and NaCl, setting in motion gene expression normally elicited by developmental processes such as flowering or environmental stress.Abbreviations IPT isopentenyl, transferase - rbcS-3A gene encoding a small subunit protein (SSU) of Rubisco from Pisum sativum - Rubisco ribulose 1,5-bisphosphate carboxylase/oxygenase     

Serotonergic Regulation of Acetylcholine Release in Rat Frontal Cortex

Abstract: The extent to which serotonin regulates the activity of cortically projecting cholinergic neurons was studied using in vivo microdialysis to monitor interstitial concentrations of acetylcholine in the frontal cortex of freely moving rats. Systemic administration of the serotonin release-inducing agent fenfluramine (3 or 10 mg/kg, i.p.) increased acetylcholine release by 110–130%. The fenfluramine-induced increase in acetylcholine release was significantly attenuated by pretreatment with the selective serotonin uptake inhibitor fluoxetine (10 mg/kg, i.p.). Pretreatment with the selective dopamine D₁ receptor antagonist SCH-23390 (0.3 mg/kg, s.c.) failed to prevent the fenfluramine-induced increase in acetylcholine release. In contrast, the serotonin 5-HT_2A receptor antagonist ketanserin (5 mg/kg, i.p.) blocked fenfluramine-induced increases in acetylcholine release. In contrast to previous studies that have concluded that serotonin has inhibitory actions on cortical acetylcholine release, the present results indicate that fenfluramine increases cortical acetylcholine release in vivo by its ability to enhance serotonin transmission and that serotonin produces these effects at least in part via actions at serotonin 5-HT_2A receptors.     

Genetical and physical assignments of equine microsatellites—first integration of anchored markers in horse genome mapping

Twenty equine microsatellites were isolated from a genomic phage library, and their genetical and physical localization was sought by linkage mapping and fluorescent in situ hybridization (FISH). Nineteen of the markers were found to be polymorphic with, in most cases, heterozygosities exceeding 50%. The markers were mapped in a Swedish reference family for gene mapping, comprising eight half-sib families from Standardbred and Icelandic horse sires. Segregation was analyzed against a set of 35 other markers typed in the pedigree. Thirteen of the microsatellites showed linkage to at least one other marker, with a total of 21 markers being involved in these linkages. In parallel, 18 of the microsatellites could be assigned to their chromosomal region by FISH. These assignments involved eight equine autosomes: ECA1, 2, 4, 6, 9, 10, 15, and 16. The genetical and physical mappings revealed by this study represent a significant extension of the current knowledge of the equine genome map. Received: 24 September 1996 / Accepted: 1 December 1996     

Structure determination of N-linked oligosaccharides engineered at the CH1 domain of humanized LL2

Two humanized antibody mutants, hLL2HCN1 and hLL2HCN5, engineeredwith CH₁ domain-appended carbohydrates (CHOs) were generatedto facilitate site-specific conjugation of radionudides andanti-cancer drugs to antibodies. Such site-specific conjugationmay minimize the incidence of immunoreactlvity perturbationas is often observed with random conjugation. Since the compositionsand structures of CHOs are important in determining the chemistry,efficiency, and extent of conjugation, the sequences of theCH₁-appended CHOs were determined by exoglycosidase digestionsand fluorophore-assisted CHO electrophoresis (FACE). The CHOspecies attached at HCN1 and HCN5 sites in hLL2HCN1 and IJLL2HCN5,respectively, were distinct from each other, heterogeneous,and extensively processed. All of these CHOs were corefucosylatedcomplex-type oligosaccharides and contained Gal (galactose)and GlcNAc (N-acetylglucosamine) residues in the outer branches.Some of the outer branches were composed of Gal     

Novel cyanoguanidines with potent oral antitumour activity

4-Pyridyl cyanoguanidines with hydrophobic aromatic side chains showed potent antiproliferative activity in the human breast and lung cancer cell lines MCF-7, NYH and H460. In vivo, treatment with N-(6-chlorophenoxyhexyl)-N′-cyano-N″-4-pyridylguanidine (18, 20 mg/kg/day po.), gave a complete remission of tumours in a model of NYH inoculated nude mice.