bluuebunny/crossref_metadata_2025_split huggingface dataset:
Transforming growth factor‐β does not alter interleukin‐1 expression in cultured human macrophages
Authors: Hurme Mikko , Sihvola Marja , Alitalo Kari , Keski‐Oja Jorma 
Published: December 2004

AbstractTransforming growth factor‐β (TGFβ) is a growth modulator that stimulates the growth of fibroblastic cells but inhibits the growth of cells of epithelial origin. TGFβ also influences the production of extracellular matrix proteins, and of proteases and the type 1 plasminogen activator inhibitor (PAI‐1) by cultured cells. TGFβ appears also to have various immunoregulatory effects, suppressing both T‐ and B‐cell activities. It has been proposed that it might increase the expression of interleukin‐1 (IL‐1) mRNA in cultured human monocytes, thus potentiating immune functions. To analyze the role of TGFβ in IL‐1 production we have now quantitated the effect of this factor on the production of biologically active IL‐1 as well as IL‐1β mRNA expression. The effect of TGFβ on IL‐1 production optimally activated with bacterial lipopolysaccharide (LPS) was also studied. It was found that IL‐1 activity and mRNA levels were rapidly elevated by LPS but not by TGFβ. Culture fluids from monocytes treated with TGFβ alone or with TGFβ plus LPS inhibited the proliferation of the test thymocytes. After gel filtration, the media from TGFβ‐treated cultures showed no activity in the molecular weight area of IL‐1 (approx. 15 kD), while the supernatants from TGFβ plus LPS‐induced cells contained IL‐1 activity in these fractions, the magnitude of which was, however, at the same level as in the culture fluids derived from cells stimulated with LPS alone. Thus our results show that the TGFβ used was biologically active but they provide no evidence for TGFβ in the regulation of IL‐1 production in human monocytes.
Transforming growth factor beta 1 (TGF‐β1) receptor expression on resting and mitogen‐activated T cells
Authors: Ellingsworth Larry , Nakayama Debra , Dasch James , Segarini Patricia , Carrillo Pedro , Waegell Wendy 
Published: December 2004

AbstractTransforming growth factor β1 (TGF‐β1) is a potent autocrine growth inhibitor of lymphocytes. In this study, the expression of TGF‐β1 binding proteins was characterized on murine splenic T cells. With an affinity cross‐linking method and by neutralizing antibodies to TGF‐β1, [125I] TGF‐β1 was found to bind to three cell surface–binding proteins (280–200 kD, 95–85 kD, 65 kD) that were differentially expressed on resting and mitogen‐stimulated T cells. Freshly prepared (resting) T cells were found to constitutively express the 95–85‐kD form of these binding proteins, whereas mitogenic stimulation by either concanavalin‐A (Con‐A), interleukin‐1 (IL‐1), interleukin‐2 (IL‐2), or 12‐tetradencanoyl‐phorbol‐13‐acetate (TPA) for 12–72 h induced the appearance of all forms of the TGF‐β1 binding proteins (280–200 kD, 95–85 kD, and 65 kD). Furthermore, antibodies that neutralized the biologic action of TGF‐β1 also blocked the binding of [125I] TGF‐β1 to all three binding proteins, suggesting that these binding proteins are involved with signal transduction. These results suggest that the expression of the TGF‐β1 receptor on T cells is regulated by T cell mitogenic signals and that a regulatory relationship may exist between T cell growth‐promoting cytokines (IL‐1 and IL‐2) and the T cell growth inhibitor, TGF‐β1.
Molecular and cellular analysis of histamine H1 receptors on cultured smooth muscle cells
Authors: Mitsuhashi Masato , Payan Donald G. 
Published: December 2004

AbstractHistamine is an important mediator of immediate hypersensitivity for both animals and humans. The action of histamine on target tissues is believed to be mediated by specific cell surface receptors, especially H1 and H2 receptors for hypersensitivity and inflammatory reactions, which involve stimulation of smooth muscle contractility, alterations in vascular permeability, and modifications in the activities of macrophages and lymphocytes. Although the nature of histamine receptors in the brain and peripheral tissues has been studied extensively by many laboratories, the molecular mechanism of histamine receptor‐mediated reactions is not fully understood, mainly because histamine receptors are incompletely characterized from the biochemical point of view. In previous studies, we have found that the cultured smooth muscle cell line DDT1MF‐2, derived from hamster vas deferens, expresses low‐affinity histamine H1 receptors and responds biochemically and functionally to H1‐specific stimulation (Mitsuhashi and Payan, J Cell Physiol 134:367, 1988). This cell line provides a model for analyzing the biochemical responses of H1 receptor‐mediated reactions in peripheral tissues. In this review, we summarized our recent progress in the study of low‐affinity H1 receptors on DDT1MF‐2 cells.
Competitive, uncompetitive, and mixed inhibitors of the alkaline phosphatase activity associated with the isolated brush border membrane of the tapeworm Hymenolepis diminuta
Authors: Pappas Peter W. , Leiby David A. 
Published: December 2004

AbstractSeveral compounds were tested as inhibitors of the alkaline phosphatase (AlkPase) activity associated with the isolated brush border membrane of the tapeworm, Hymenolepis diminuta. Molybdate, arsenate, arsenite and β‐glycerophosphate (BGP) were competitive inhibitors of the hydrolysis of p‐nitrophenyl phosphate, while levamisole and clorsulon were uncompetitive and mixed inhibitors, respectively. Molybdate was also a competitive inhibitor of the hydrolysis of BGP and 5′‐adenosine monophosphate, and levamisole was an uncompetitive inhibitor of BGP hydrolysis. The apparent inhibitor constants (K′i) for molybdate and levamisole were virtually identical regardless of the substrate, and these data support the hypothesis that the AlkPase activity is represented by a single membrane‐bound enzyme with low substrate specificity. Quinacrine, Hg2+, and ethylenediaminetetraacetate were also potent inhibitors of the AlkPase activity, but the mechanisms by which these latter three inhibitors function were not clear.
Differential regulation of basic protein phosphorylation by calcium phospholipid and cyclic‐AMP‐dependent protein kinases
Authors: Dawson Glyn , McAtee Patrick 
Published: December 2004

AbstractMyelin basic protein, an 80‐kilodalton (kDa) protein in rat oligodendrocytes, and an 80‐kDa basic protein in neuroblastoma × neonatal Chinese hamster brain explant hybrids were phosphorylated extensively when the cells were treated with either phorbol esters (TPA) or diacylglycerols (e.g., oleyoyl‐acetyl‐glycerol). TPA‐stimulated phosphorylation was inhibited by pre‐incubation with 50 μM psychosine (galactosyl‐sphingosine), confirming that it is mediated through the phospholipid‐dependent protein kinase C (PK‐C). Surprisingly, phosphorylation of these proteins was inhibited by incubation of cells with agents which result in activation of cyclic‐AMP‐dependent protein kinase (dibutyryl cyclic AMP or forskolin). In contrast, phosphorylation of other nonbasic proteins, for example, the oligodendrocyte‐specific 2′,3′‐cyclic nucleotide phosphohydrolase, was stimulated under these conditions (Vartanian et al.: Proceedings of the National Academy of Sciences of the United States of America 85:939, 1988). The possible role of cyclic AMP in activating specific phosphatases or restricting the availability of diacylglycerol for PK‐C activation is discussed.
Coupling of antagonistic signalling pathways in modulation of neutrophil function
Authors: Mueller Heinz , Sklar Larry A. 
Published: December 2004

AbstractModulation of neutrophil activation by catecholamines reflects a fine‐tuning by coupling inhibitory and stimulatory receptor pathways. The catecholamine isoproterenol (ISO) binds to beta‐adrenergic cell surface receptors and thereby inhibits cell responses such as O production stimulated by formyl peptides. However, ISO did not inhibit O generation activated by 1 μM ionophore A23187, the protein kinase C activators phorbol ester (PMA, 100 ng/ml) and oleoylacetylglycerol (OAG, 50 μM), and the G‐protein activator NaF (40 mM). Furthermore, the overall kinetics of oxidant production in the presence of ISO were unchanged when cells were stimulated with PMA, OAG, A23187, and NaF. These results would imply that neither intracellular calcium, the activation of protein kinase C, nor the activation of G‐protein are the primary target of the inhibitory pathway. Accordingly, pertussis toxin did not block PMA or NaF‐stimulated superoxide generation. In contrast, formyl peptide‐dependent GTPase activity is inhibited by ISO in sonicated cell preparations. Since ISO increases the cAMP concentration in the cell, the possibility is raised that a cAMP‐dependent kinase inhibits signal transduction in part by blocking the interaction of this receptor with its G‐protein.
Design and synthesis of conformationally restricted phospholipids as phospholipase A2 inhibitors
Authors: Magolda R. L. , Galbraith W. 
Published: December 2004

AbstractThe use of conformationally restricted phospholipids 1 and 2 has been employed to understand the conformational preference of phospholipase A2 (PLA2) for substrate phospholipids. Inhibition of porcine pancreatic PLA2 with 1 and 2 indicated a two‐ to fivefold preference for the distal isomer 2 over the proximal isomer 1. Based upon these studies, both side‐chains of the substrate phospholipid appear to occupy the lipid binding domains near the active site with the side‐chains further apart most preferred by PLA2.
Differential effect of dexamethasone on the regulation of phospholipase A2 and prostanoid synthesis in undifferentiated and phorbolester‐differentiated U937 cells
Authors: Koehler L. , Hass R. , Goppelt‐Struebe M. , Kaever V. , Resch K. 
Published: December 2004

AbstractThe human undifferentiated histiocytic cell‐line U937 can be induced to differentiate by incubation with 12‐0‐tetradecanoylphorbol‐13‐acetate (TPA) into macrophage‐like cells. Dexamethasone reduced the prostaglandin production in TPA‐differentiated U937 cells dose dependently, whereas undifferentiated U937 cells were dexamethasone insensitive. Concomitantly phospholipase A2, the enzyme liberating the prostaglandin precursor arachidonic acid, was inhibited by dexamethasone in TPA‐differentiated but not in undifferentiated U937 cells. The activity of lysophosphatide acyltransferase, the key enzyme of fatty acid reacylation into phospholipids, remained unchanged both in undifferentiated and TPA‐differentiated U937 cells. The data suggest that responsiveness to glucocorticoid‐dependent regulation of prostanoid synthesis is acquired by cells of the monocyte‐macrophage lineage late in differentiation.
Altered actin and immunoglobulin Cμ expression in nitrogen mustard‐resistant human Burkitt lymphoma cells
Authors: Tan K. B. , Grillone Lisa , Boyce Rebecca , Crooke Stanley T. 
Published: December 2004

AbstractRaji‐HN2 is a B cell lymphoma (Burkitt lymphoma) line that was made resistant to nitrogen mustard. The drug‐resistant phenotype was accompanied by changes in gene expression. The expression of four unrelated genes was examined by Northern blot analysis. Raji‐HN2 cells were found to contain about twice the number of actin mRNA found in Raji cells. Both cell lines were found to contain equivalent amounts of β2‐microglobulin, c‐myc oncogene, and immunoglobulin Cμ mRNAs. The Cμ mRNA was, however, larger in size in Raji‐HN2 cells. Alterations in actin and Cμ mRNAs in Raji‐HN2 cells were not due to gene amplification or rearrangement because Southern blot analysis revealed no changes in the genomic organization of these genes. The increased actin mRNA content was correlated with an increased actin content of Raji‐HN2 cells. The F‐actin (stained with 7‐nitrobenz‐2‐oxa‐1,3‐diazolylphallacidin) content of single cells was quantitated in a meridian interactive laser cytometer. Raji‐HN2 cells contained about twice the amount of F‐actin present in the parental Raji cells. Similar results were obtained when large populations, 106 cells each, were examined in a flow cytometer.
Effects of bombesin on human small cell lung cancer cells: Evidence for a subset of bombesin non‐responsive cell lines
Authors: Kado‐Fong Helen , Malfroy Bernard 
Published: December 2004

AbstractThe effects of bombesin on three human small cell lung carcinoma cell (SCLC) lines (NCI‐H69, NCI‐H128, and NCI‐H345) have been examined and compared to the effects of the peptide on the mouse fibroblast cell line Swiss 3T3, and the rat pituitary tumor cell line GH3W5. While all three SCLC lines expressed messenger RNA encoding pro‐gastrin releasing peptide (GRP), only the NCI‐H345 cells expressed detectable membrane receptors for GRP and responded to nanomolar concentrations of bombesin as shown by 125I‐GRP binding, total inositol phosphate accumulation, and increased clonal growth in soft agarose. These data show that some SCLC lines are insensitive to bombesin and do not express detectable membrane receptors for GRP.
Culture of primary lung tumors using medium conditioned by a lung carcinoma cell line
Authors: Siegfried Jill M. 
Published: December 2004

AbstractMedium conditioned by the established lung tumor cell line A549 was used as a supplement to culture cells from primary solid lung tumors. Of 36 cases placed into culture, primary cells were obtained in 33 (91.7%). Of 29 cases in which subcultures were attempted, 18 (62.1%) were successful. Nine cell lines have been established by this technique to date. In growth assays, conditioned medium (CM) was found to stimulate both monolayer colony formation and growth in semi‐solid medium of cells cultured from primary solid tumors. CM has been found to contain factors with the properties of both transforming growth factorα (TGFα) and insulin‐like growth factor‐I (IGF‐I). The addition of a combination of these factors as purified peptides to basal medium at levels found in CM (0.1–0.5 ng/ml) stimulated colony formation of lung tumor cells by up to fourfold. These results indicate that secretion of growth factors may be important in tumor growth in vivo, and that use of CM may be a valuable tool for obtaining cultures from primary solid tumors.
Transforming growth factor‐β1 binds to immobilized fibronectin
Authors: Mooradian Daniel L. , Lucas Roger C. , Weatherbee James A. , Furcht Leo T. 
Published: December 2004

AbstractWe have characterized the interaction of homodimeric porcine transforming growth factor‐β1 (TGF‐β1) with affinity‐purified human plasma fibronectin. Using a solid‐phase binding assay, we have demonstrated that TGF‐β1 binds to fibronectin immobilized on Immunlon ITM microtiter plates. TGF‐β1 binding increased with time, reaching a plateau after 4–6 h, and was dependent upon the concentration of both labeled TGF‐β1 and immobilized fibronectin present. The binding of radiolabeled TGF‐β1 to fibronectin was saturable and was reduced 75% in the presence of a 100‐fold excess of unlabeled TGF‐β1. TGF‐β1 bound to fibronectin with an association rate constant (Ka) of 2.96 × 103 M−1 s−1 and did not readily dissociate under various conditions. The binding of TGF‐β1 to fibronection was insensitive to variations in ionic strength over a range of 0.1–1.0 M NaCl and was relatively insensitive to divalent cation concentration in the range of 0.1–10.0 mM as well. These data suggest that the binding of TGF‐β1 to fibronectin may not be dependent upon the interaction of charged amino acids within these two molecules. However, the binding of TGF‐β1 to fibronectin was strongly pH‐dependent and binding decreased dramatically below pH 4.0 and above pH 10.0, suggesting that charged amino acids may influence TGF‐β1/fibronectin interactions. The association of TGF‐β1 with immobilized fibronectin or other extracellular matrix components and subsequent dissociation under acidic conditions or by an as‐yet‐unidentified mechanism may play a role in the distribution and/or activity of this potent growth regulator at sites of tissue injury and inflammation in vivo.
SV40 T antigen alone drives karyotype instability that precedes neoplastic transformation of human diploid fibroblasts
Authors: Ray F. Andrew , Peabody David S. , Cooper Janet L. , Cram L. Scott , Kraemer Paul M. 
Published: December 2004

AbstractTo define the role of SV40 large T antigen in the transformation and immortalization of human cells, we haye constructed a plasmid lacking most of the unique coding sequences of small t antigen as well as the SV40 origin of replication. The promoter for T antigen, which lies within the origin of replication, was deleted and replaced by the Rous sarcoma virus promoter. This minimal construct was co‐electroporated into normal human fibroblasts of neonatal origin along with a plasmid containing the neomycin resistance gene (neo). Three G418‐resistant, T antigen‐positive clones were expanded and compared to three T antigen‐positive clones that received the pSV3neo plasmid (capable of expressing large and small T proteins and having two origins of replication). Autonomous replication of plasmid DNA was observed in all three clones that received pSV3neo but not in any of the three origin minus clones. Immediately after clonal expansion, several parameters of neoplastic transformation were assayed. Low percentages of cells in T antigen‐positive populations were anchorage independent or capable of forming colonies in 1% fetal bovine serum. The T antigen‐positive clones generally exhibited an extended lifespan in culture but rarely became immortalized. Large numbers of dead cells were continually generated in all T antigen‐positive, pre‐crisis populations. Ninety‐nine percent of all Tantigen‐positive cells had numerical or structural chromosome aberrations. Control cells that received the neo gene did not have an extended life span, did not have noticeable numbers of dead cells, and did not exhibit karyotype instability. We suggest that the role of T antigen protein in the transformation process is to generate genetic hypervariability, leading to various consequences including neoplastic transformation and cell death.
Purification of transforming growth factor type e
Authors: Parnell Pamela G. , Wunderlich John , Carter Bobbie , Halper Jaroslava 
Published: December 2004

AbstractTransforming growth factor type e (TGFe) is a heat‐ and acid‐stable polypeptide with an apparent molecular weight of 22,000, which stimulates the proliferation of certain epithelial and mesenchymal cells in monolayer and soft agar. TGFe has been purified to homogeneity. Initial acid‐ethanol extraction of bovine kidney was followed by batch ion‐exchange chromatography utilizing Bio Rex 70 resin. The activity eluted from the Bio Rex 70 resin was concentrated and diafiltered using an Amicon concentrator equipped with an SIY10 spiral membrane, then was further purified by Bio‐Gel P‐60 molecular sieve chromatography. Active fractions from molecular sieve chromatography were pooled and purified by heparin‐Sepharose affinity chromatography, followed by reverse‐phase high‐performance liquid chromatography using a microbore C‐8 column. The final purification step involved electroelution of TGFe separated by sodium dodecyl sulfate‐polyacrylamide gel electrophoresis (SDS‐PAGE). Purity of TGFe was assessed to be greater than 90%.
Plasma inter‐α‐trypsin inhibitor‐related urinary glycoprotein EDC 1 inhibits the growth of a Burkitt's lymphoma cell line
Authors: Chawla Rajender K. , Lawson David H. , Travis James 
Published: December 2004

AbstractA homogeneous preparation of a urinary glycoprotein has been isolated from urine of patients with malignant melanoma and advanced adenocarcinomas of colon and lung. This molecule, Mr 30 kDa, is homologous to EDC1, a proteinase inhibitor antigenically related to plasma inter‐α‐trypsin inhibitor (IATI) originally isolated from the urine of a leukemic patient, E.D. The newly isolated EDC1 inhibits cellular proliferation of a Burkitt's lymphoma cell line, Raji, growing in serum‐free medium supplemented with insulin, transferrin, selenium, and linoleic acid. This concentration‐dependent inhibitory effect was monitored in terms of change in cell number and 3H‐thymidine incorporation. The growth of cells treated with ∼3.3 pmol EDCl/ml was 50% that of the control group by both assays. EDC1 was not cytotoxic to the cells because the EDC1‐treated cells excluded trypan blue and resumed normal growth after removal of EDC1. In addition, EDC1 treatment of Raji cells prelabeled with 3H‐labeled DNA did not release more radioactivity into the conditioned medium than the untreated labeled cells. EDC1 did not affect the growth of Hs2B2, a B‐lymphoblast cell line, and Hs294T, a human malignant melanoma cell line. Equimolar and larger quantities of other proteinase inhibitors with inhibitory profiles similar to that of EDC1 (α‐1 proteinase inhibitor, soybean trypsin inhibitor, lima bean trypsin inhibitor, and turkey ovomucoid) did not affect the growth of Raji cells. Raji cells have an absolute requirement of transferrin as a nutrient and require insulin to modulate the expression of transferrin receptors. The cells also synthesize interleukin‐I as an autocrine growth stimulator. EDC1 did not form a detectable complex with transferrin, insulin, or any autocrine factor synthesized by the cells.
Solubilization and characterization of a lactogenic receptor from human placental chorion membranes
Authors: Ormandy Christopher J. , Clarke Christine L. , Sutherland Robert L. 
Published: December 2004

AbstractProlactin has wide range of actions, including osmoregulation and the control of mammary gland development and lactation. These effects are mediated through a high‐affinity cell surface receptor, which has been well characterized in a number of animal tissues. The molecular characteristics of the human receptor are unknown, however. The present studies were initiated, therefore, to determine the binding and molecular characteristics of the lactogenic receptor of human placental chorion membranes. Subcellular fractionation studies showed that the bulk of the receptor sedimented in the microsomal fraction at 45,000gav. Endogenous ligand was dissociated from the receptor with 3.5 M MgCl2 or 0.05 M acetate buffer (pH 4.8) with preservation of binding activity. The microsomal receptor bound human growth hormone (hGH), human prolactin(hPRL), ovine prolactin (oPRL), and human placental lactogen (hPL) but not non‐primate growth hormones, indicating a narrow specificity for lactogenic hormones. The binding was only partially reversible in agreement with the know binding kinetics of animal lactogenic receptor. The receptor was solubilized with 45% yield from the microsomes using 16 mM 3‐[(3‐cholamidopropyl)dimethylammonio]‐l‐propane sulphonate (CHAPS) detergent‐250 mM NaCL, and the binding activity was fully restored by a two‐fold dilution in the binding reaction to reveal a KD of 0.8 nM for hGH and a binding capacity of 200 fmol of specifically bound hGH per mg of microsomal protein. Gel filtration chromatography indicated the minimum molecular weight of the ligand‐receptor complex was approximately 60,000 daltons, and sodium dodecyl sulphate polyacrylaminde gel electrophoresis (SDS‐PAGE) of covalently cross‐linked 125I‐hGH‐receptor complexes revealed a molecular size of 58,000 daltons. When account was taken of the contribution of the ligand, a molecular weight of 36,000 for the receptor's binding domain was obtained. These data indicate that the chorion lactogenic receptor has very similar binding and molecular characteristics to the lactogenic receptors from other mammalian species. Chorion membranes are thus a convenient source of material for the further purification and characterization of the human lactogenic receptor.