bluuebunny/crossref_metadata_2025_split huggingface dataset:
Control of cell cycle entry and progression in mitogen‐stimulated human B lymphocytes
Authors: Takase Kozo , Terada Naohiro , Lucas Joseph J. , Gelfand Erwin W. 
Published: February 2005

AbstractTonsillar B lymphocytes were stimulated to proliferate by the mitogenic combination of phorbol dibutyrate and ionomycin. Progression through the cell cycle was monitored by measurements of cellular DNA and RNA content using flow cytometry. Changes in surface expression of class II MHC antigens and CD20 antigen were also monitored as early parameters of B lymphocyte activation and cell cycle progression. The results showed that about 60% of the population synchronously entered and progressed through the cell cycle. The transition from the resting state, signaled by increased RNA content, occurred about 12 to 24 hr after stimulation; S phase entry occurred at about 36 hr. Small, variable populations of cells appeared to be unresponsive to the stimuli, either because they were “preactivated” before in vitro stimulation or were already dying. The kinetics of appearance and accumulation of several cell cycle regulated/regulatory proteins were followed by immunoblotting. The proliferating cell nuclear antigen (PCNA) cyclin A and p33cdk2 proteins were either absent or present in very low amounts in resting cells and first became detectable in increased amount beginning at about 24 hr after stimulation; increased p34cdc2 protein was not detected until about 36 hr. Increased cellular content and phosphorylation of the p110Rb protein was already obvious by 24 hr after stimulation. The effects of several immunosuppressive agents were examined using purified B cells. Both cyclosporin A and an FK506 analogue were shown to inhibit proliferation of B lymphocytes, at the low doses also inhibitory to T cells. © 1995 Wiley‐Liss, Inc.
Influence of age, sex, and dietary restriction on intracellular free calcium responses of CD4+ lymphocytes in rhesus monkeys (Macaca mulatta)
Authors: Grossmann Angelika , Rabinovitch Peter S. , Lane Mark A. , Jinneman John C. , Ingram Donald K. , Wolf Norman S. , Cutler Richard G. , Roth George S. 
Published: February 2005

AbstractThe influence of aging and dietary restriction on increase in intracellular free calcium ([Ca2+]i) of CD4+ lymphocytes from Macaca mulatta was examined after stimulation with anti‐CD3 mAb. We used a flow cytometric assay with the dye indo‐1 and either direct or reciprocal immunofluorescent staining to dientify CD4+ cells. After stimulation with anti‐CD3 mAb, intracellular free calcium responses were reduced in CD4+ lymphocytes from old male and female ad libitum fed monkeys compared to young and adult male or female monkeys. Old female monkeys had significantly lower [Ca2+]i than did old male monkeys. The reduced responses were in part related to a decreased percentage of responding cells. Dietary restrition of males over a four‐year period did not alter [Ca2+]i response compared to ad libitum fed male monkeys. Female monkeys of all ages (which were restricted only for four months) also had similar [Ca2+]i responses to ad libitum fed controls. Our data suggest that age‐related changes in [Ca2+]i responses are similar between humans and M. mulatta, and that over these intervals, no effects of caloric restrictions can be detected. © 1995 Wiley‐Liss, Inc.
EGF‐mediated phosphorylation of extracellular signal‐regulated kinases in osteoblastic cells
Authors: Zhang Wenyu , Dziak Rosemary M. , Aletta John M. 
Published: February 2005

AbstractEpidermal growth factor (EGF) induces a rapid increase in the phosphorylation of extracellular signal‐regulated kinases (ERKs) in the human osteosarcoma osteoblastic cell line G292 and in primary cultures of rat osteoblastic cells. This phosphorylation is transient and time‐dependent. Maximal stimulation is attained within 1 min in G292 and within 5 min in rat osteoblastic cells. Enzymatic activity in G292 cells is also induced rapidly after EGF stimulation. Western blot analysis revealed that enhancement of the phosphorylation of ERKs in the EGF‐stimulated cells is not due to an increase in ERK protein, since EGF‐treatment does not lead to an increase in the absolute amount of ERKs present even after 2 days of stimulation. The pattern of expression of the ERKs observed in the two cell types differs in the apparent molecular weights observed. The most slowly migrating immunoreactive protein (∼45 kDa) in normal rat osteoblastic cells is ERK1, identified by an ERK1‐selective antiserum. The same antiserum reacts only weakly with one of the ERK proteins (44 kDa) blotted from the human osteosarcoma cell line G292. Phorbol 12‐myristate 13‐acetate (PMA) is also capable of inducing ERK phosphorylation, albeit to a lesser degree. The combination of PMA and EGF does not produce a greater response than EGF alone. The role of protein kinase C (PKC) in the EGF‐stimulated ERK signaling pathway was further examined by inhibition of PKC with the staurosporine analog, CGP41251, and by down‐regulation of PKC via chronic treatment with PMA. Chronic PMA treatment results in a partial inhibition of the EGF‐mediated phosphorylation. CGP41251 completely abolishes the increased ERK activity produced by PMA, but the effect of EGF in this regard is potentiated. We conclude that PKC and EGF act through parallel pathways to stimulate ERK phosphorylation and activity. The inhibitor studies, in addition, indicate that activation of PKC may moderate the actions of the EGF pathway via a tonic inhibitory feedback. © 1995 Wiley‐Liss, Inc.
No evidence for a tumor necrosis factor α stimulated 2‐methylaminoisobutyric acid uptake in hepatocyte monolayer
Authors: Lim Soo‐Kyung , de Bandt Jean‐Pascal , Aussel Christian , Pernet Pascal , Giboudeau Jacqueline , Cynober Luc 
Published: February 2005

AbstractThis study investigates the short‐tem effects of glucagon and human recombinant tumor necrosis factor α (TNFα) singly and in association on 2‐methylaminoisobutyric acid (MeAIB) transport in hepatocyte monolayers. As expected, glucagon induced a time‐dependent stimulation of MeAIB transport. In our experimental conditions, TNFα did not induce cytolysis. A 2 hour exposure to TNFα (0.05–500 ng/I) with or without glucagon (10−9 to 10−6 M) did not modify the basal or glucagon‐stimulated MeAIB transport. Varying the duration of exposure to TNFα 5 ng/I up to 6 h was equally ineffective. The presence of hydrocortisone potentiated the glucagon‐stimulated transport, but TNFα remained ineffective. Finally, the association of interferon (IFNγ) with TNFα and/or glucagon was unable to modify the transport activity. These data demonstrate that TNFα does not exert a direct effect on MeAIB transport in hepatocytes, at least on a short‐term basis. © 1995 Wiley‐Liss, Inc.
Association of hepatic β2‐adrenergic receptor gene transcript destabilization during postnatal development in the sprague‐dawley rat with a Mr 85,000 protein that binds selectively to the β2‐adrenergic receptor mRNA 3′‐untranslated region
Authors: Baeyens Dennis A. , Cornett Lawrence E. 
Published: February 2005

AbstractIn the liver, transcript destabilization contributes to the decrease in steady‐state levels of β2‐adrenergic receptor mRNA that occurs during early postnatal development in the rat. From genomic DNA, polymerase chain reaction (PCR) was used to amplify a 718‐basepair (bp) fragment of the β2‐adrenergic receptor gene including the entire 3′‐untranslated region. Results from SDS‐gel electrophoresis and autoradiography demonstrated a Mr 85,000 cellular factor present in postnatal day 60, but not fetal day 18 rat liver that was ultraviolet (UV) light‐crosslinked to in vitro transcribed β2‐adrenergic receptor RNA 3′‐untranslated region. Unlabeled β2‐adrenergic receptor RNA 3′‐untranslated region, but not mouse β‐actin RNA, competed with labeled β2‐adrenergic receptor RNA 3′‐untranslated region for binding to the Mr 85,000 protein. Cross‐linking of the β2‐adrenergic receptor RNA 3′‐untranslated region to the Mr 85,000 protein was inhibited by the ribohomopolymer poly(U), with poly(A), poly(C) and poly(G) having little or no effect. Thus, a Mr 85,000 protein has been identified in adult male rat liver that may interact with U‐rich sequences in the 3′‐untranslated region of the β2‐adrenergic receptor mRNA and may account for the decreased stability of hepatic β2‐adrenergic receptor gene transcripts that occurs during development. © 1995 Wiley‐Liss, Inc.
Lipopolysaccharides stimulate Na‐dependent transport in alveolar cells and protect against oxidant injury
Authors: Azarian Réza , Clerici Christine , Couette Sylvianne , Friedlander Gérard , Amiel Claude 
Published: February 2005

AbstractWe have evaluated the effect of lipopolysaccharides (LPS), endotoxins from gram negative bacteria, on sodium‐coupled amino acid and phosphate transport by alveolar epithelial type II cells and on their alteration induced by oxidants. Alveolar type II cells were obtained by enzymatic digestion of rat lung and grown for 24 h prior to incubation with LPS and then exposed or not exposed to H2O2 (2.5 mM; 20 min). LPS (10 μg/ml, 24 h) induced a significant increase in the Na‐dependent component of alanine and phosphate uptake while they decreased Na, K‐ATPase activity measured by ouabain‐sensitive 86Rb influx. We showed that this stimulatory effect i) was independent from macrophage products since it was not mimicked either by supernatant of LPS‐treated alveolar macrophages or by pretreatment with tumor necrosis factor and/or interleukin 1 and ii) was dependent on protein synthesis since it was abolished by protein synthesis inhibitors cycloheximide and actinomycin D. Moreover, LPS blunted H2O2‐induced decrease of Na‐dependent alanine and phosphate uptake. This protective effect of LPS against H2O2 injury i) was independent of macrophage products, ii) was abolished by cycloheximide, and iii) was not associated with either changes in extracellular H2O2 clearance or catalase and glutathione peroxidase activities. We conclude that, in alveolar type II cells, LPS stimulate sodium‐coupled transport by a process involving protein synthesis and partially prevent H2O2‐induced decrease of Na‐coupled transport without discernible change in antioxidant activities. © 1995 Wiley‐Liss, Inc.
Prolactin and epidermal growth factor regulation of the proliferation, morphogenesis, and functional differentiation of normal rat mammary epithelial cells in three dimensional primary culture
Authors: Darcy Kathleen M. , Shoemaker Suzanne F. , Lee Ping‐Ping H. , Vaughan Mary M. , Black Jennifer D. , Ip Margot M. 
Published: February 2005

AbstractThe epithelial cell‐specific effects of prolactin and epidermal growth factor (EGF) on the development of normal rat mammary epithelial cells (MEC) were evaluated using a three dimensional primary culture model developed in our laboratory. Non‐milk‐producing MEC were isolated as spherical end bud‐like mammary epithelial organoids (MEO) from pubescent virgin female rats. The cultured MEO developed into elaborate multilobular and lobuloductal alveolar organoids composed of cytologically and functionally differentiated MEC. Prolactin (0.01–10 μg/ml) and EGF (1–100 ng/ml) were each required for induction of cell growth, extensive alveolar, as well as multilobular branching morphogenesis, and casein accumulation. MEO cultured without prolactin for 14 days remained sensitive to the mitogenic, morphogenic, and lactogenic effects of prolactin upon subsequent exposure. Similarly, cells cultured in the absence of EGF remained sensitive to the mitogenic and lactogenic effects of EGF, but were less responsive to its morphogenic effects when it was added on day 14 of a 21‐day culture period. If exposure to prolactin was terminated after the first week, the magnitude of the mitogenic and lactogenic effects, but not the morphogenic response was decreased. Removal of EGF on day 7 also reduced the mitogenic response, but did not have any effect on the magnitude of the lactogenic or morphogenic responses. These studies demonstrate that physiologically relevant development of normal MEC can be induced in culture and that this model system can be used to study the mechanisms by which prolactin and EGF regulate the complex developmental pathways operative in the mammary gland. © 1995 Wiley‐Liss, Inc.
Binding of platelet‐derived growth factor and low density lipoproteins to glycosaminoglycan species produced by human arterial smooth muscle cells
Authors: Fager Gunnar , Camejo German , Olsson Urban , Östergren‐Lundén Gunnel , Lustig Florentyna , Bondjers Göran 
Published: February 2005

AbstractThe platelet‐derived growth factor (PDGF) binds via a defined amino acid sequence to heparin (Fager et al., 1992, In Vitro Cell. Dev. Biol., 28A:176–180) and the protein moiety of low density lipoproteins (LDL; apo B‐100) via a similar sequence to chondroitin sulfate (Camejo et al., 1988, Arteriosclerosis Thromb., 8:368–377). In this study, synthetic oligopeptides were used to explore the capacity of smooth muscle cell‐derived glycosaminoglycans to bind to the critical sequences of PDGF and apo B‐100. In vitro, proliferating human arterial smooth muscle cells synthesized twice as much proteoglycans as did quiescent cells. The dominating glycosaminoglycan side chains were chondroitin and heparan sulfates in secreted and cell‐associated proteoglycans, respectively. The chondroitin sulfate‐rich proteoglycans had a higher molecular size and were to a larger extent secreted into the culture medium than the heparan and dermatan sulfate‐rich proteoglycans. Heparan, dermatan, and chondroitin sulfates bound to the PDGF‐derived oligopeptide with affinities similar to those of heparin. However, while heparan and dermatan sulfates both inhibited DNA synthesis in human arterial smooth muscle cells, chondroitin sulfate had no such inhibitory effect. Like the PDGF‐derived oligopeptide, the apo B‐100‐derived oligopeptide bound to these glycosaminoglycans. At the same time, both oligopeptides displaced bound LDL from chondroitin sulfate in vitro and released the block on DNA synthesis in smooth muscle cells that heparin induced in culture. Thus, chondroitin, dermatan, and heparan sulfates produced by arterial smooth muscle cells may bind LDL and PDGF competitively in atherogenesis but only heparan and dermatan sulfates inhibit cellular DNA synthesis. LDL and PDGF deposition may occur by binding to similar binding sites on glycosaminoglycans derived from smooth muscle cells within atherosclerotic lesions. © 1995 Wiley‐Liss, Inc.
Inhibition of N‐linked glycosylation induces early apoptosis in human promyelocytic HL‐60 cells
Authors: Pérez‐Sala Dolores , Mollinedo Faustino 
Published: February 2005

AbstractInhibition of protein N‐glycosylation by tunicamycin induced morphological changes characteristic of apoptosis in human promyelocytic HL‐60 cells. Internu‐cleosomal DMA fragmentation could be detected after short‐time incubation (between 6 and 9 h) of HL‐60 cells with low doses of tunicamycin (0.05 μg/ml). Under these conditions the synthesis of glycoproteins was reduced to 17% of control values, while no significant changes in the rates of total protein synthesis could be observed. Tunicamycin ability to induce DNA fragmentation was in good correlation with its potency as glycosylation inhibitor in several myeloid cell lines. Tunicamycin‐induced apoptosis was potentiated by activation of protein kinease C (PKC) by phorbol esters and partially prevented by the PKC inhibitor staurosporine. Inhibitors of RNA and protein synthesis displayed a protective effect. Treatment of HL‐60 cells with tunicamycin did not elicit the expression of cell surface differentiation antigens or their ability to generate superoxide anion. In contrast, tunicamycin significantly inhibited these processes during dimethyl sulfoxide (DMSO)‐induced myeloid differentiation. These observations indicate that the main effect of tunicamycin in HL‐60 cells is the induction of apoptosis. © 1995 Wiley‐Liss, Inc.
Differential effects of glucocorticoids on insulin‐like growth factor I action in cultured human fibroblasts
Authors: Conover Cheryl A. , Hintz Raymond L. , Johnson Ben F. 
Published: February 2005

AbstractGlucocorticoids act synergistically with insulin‐like growth factor I (IGF‐I) to stimulate DNA synthesis and replication of cultured human fibroblasts. In the present study, we further define glucocorticoid and IGF‐I interactive effects on human fibroblast metabolism and growth. IGF‐I stimulated dose‐dependent increases in early metabolic events. Half‐maximal effectiveness was seen at 5–8 ng/ml IGF‐I, with mean maximal responses of 1.5‐, 2‐, and 6‐fold for [3H]2‐deoxyglucose uptake, [14C]glucose incorporation, and [14C]aminoisobutyric acid (AIB) uptake, respectively. A 48‐hour preincubation with 10−7 M dexamethasone markedly enhanced both the sensitivity and maximal effectiveness of IGF‐I stimulation of AIB uptake. In contrast, dexamethasone had no effect on IGF‐I‐stimulated glucose uptake and utilization. Maximum specific binding of [125I]IGF‐I to fibroblast monolayers was identical in ethanol control and glucocorticoid‐treated cells, with 50% displacement at ∼5 ng/ml IGF‐I. In addition to its synergism with IGF‐I, preincubation with dexamethasone augmented insulin and epidermal growth factor (EGF) stimulation of [3H]thymidine incorporation; dexamethasone had no effect on platelet‐derived growth factor or fibroblast growth factor action. Two‐dimensional gel electrophoresis identified two specific glucocorticoid‐induced proteins in human fibroblast cell extracts with molecular weights of 45K and 53K and pls of 6.8 and 6.3, respectively. These data indicate that IGF‐I receptor‐mediated actions in human fibroblasts are differentially modulated by glucocorticoids. Glucocorticoids are synergistic with IGF‐I in stimulating mitogenesis and amino acid uptake, without having any apparent effect on IGF‐I‐stimulated glucose metabolism. Glucocorticoid enhancement of growth factor bioactivity may involve modulation of a regulatory event in the mitogenic signaling pathway subsequent to cell surface receptor activation. © 1995 Wiley‐Liss, Inc.
Activation of junB and c‐myc primary response genes by interleukin 9 in a human factor‐dependent cell line
Authors: Kang Li Ya , Yang Yu‐Chung 
Published: February 2005

AbstractInterleukin 9 (IL‐9) stimulates the proliferation of various hematopoietic cell types. To elucidate the molecular mechanisms underlying the cell proliferation action, immediate‐early gene expression elicited by IL‐9 in a human factor‐dependent cell line, MO7e, was studied. IL‐9 stimulation resulted in a rapid and transient elevation of primary response genes including junB and c‐myc. The differential effects of protein kinase inhibitors, herbimycin A, genistein, and H‐7 on the steady‐state mRNA level and the transcription rate of junB and c‐myc genes triggered by IL‐9 were also investigated. Herbimycin A, but not genistein, specifically inhibited the expression of junB steady‐state mRNA and the in vitro transcription of the junB gene. IL‐9‐enhanced c‐myc gene expression was completely inhibited by both herbimycin A and genistein at the level of transcriptional initiation. H‐7 failed to inhibit c‐myc, but partially abolished junB mRNA induction. The role of protein kinase C in IL‐9‐mediated junB induction was also examined. The different responses of junB and c‐myc messages to protein kinase inhibitors suggested that more than one pathway may be involved in IL‐9‐mediated signal transduction which leads to the expression of junB and c‐myc genes. © 1995 Wiley‐Liss, Inc.
Induction of bovine bronchial epithelial cell filopodia by tetradecanoyl phorbol acetate, calcium ionophore, and lysophosphatidic acid
Authors: Beckmann Joe D. , Romberger Debra J. , Rennard Stephen I. , Spurzem John R. 
Published: February 2005

AbstractThe morphological responses of primary bovine bronchial epithelial cells (BBECs) cultured in serum‐free medium to protein kinase activators have been examined. When attached to type I collagen‐coated tissue culture dishes, the cells responded to tetradecanoyl phorbol acetate (TPA), calcium ionophore A23187, and lysophosphatidic acid (LPA) by extruding filopodia. In contrast, no morphological changes were elicited by exposures to either epinephrine or dibutyryl‐cAMP. Formation of filopodia was accompanied by actin filament reorganization as demonstrated by staining with labeled phalloidin. Exposures to varied TPA concentrations for 2 h showed maximal stimulation of filopodial extrusions at 10 nM TPA with half‐maximal stimulation at 1 nM. Time‐course measurements with 10 nM TPA showed filopodia formation within 30 min of exposure, with 85% of the BBECs being filopodia positive after 5 h. Filopodia induction in 20‐30% of the cells could be achieved by 1–100 m̈M LPA concentrations. BBECs acquired increasing resistance to TPA‐induced filopodia during the initial 5 days in culture; however, responsiveness to TPA was regenerated by mild treatment with trypsin. Inclusion of fibronectin or vitronectin into the attachment matrix had no effects on the rates or extent of TPA‐induced filopodia formation. © 1995 Wiley‐Liss, Inc.
Magnesium‐Dependent stimulation of protein synthesis by the insulin mimic, pervanadate
Authors: Barnes David M. , Sykes Destiny B. , Smith James J. , Miller David S. 
Published: February 2005

AbstractThe insulin mimic, peroxide of vanadate (pervanadate), stimulated 35S‐methionine incorporation into Xenopus oocyte protein in a Mg2+‐dependent manner. Reducing the extracellular Mg2+ concentration from 1.0 to 0.1 mM decreased the pervanadate‐stimulated component of incorporation by 35%; with 0.01 mM Mg2+ or lower, the pervanadate‐stimulated component was abolished. In addition, reducing extracellular Mg2+ to 0.01 mM inhibited about 50% of the insulinstimulated component of methionine incorporation. Mg2+ depletion had no effects on incorporation in controls or when protein synthesis was stimulated by Zn2+ or bovine growth hormone. Thus, not all substances that stimulated protein synthesis showed a dependence on extracellular Mg2+. Reducing extracellular Ca2+ had no effects on methionine incorporation in control cells or in cells stimulated by pervanadate or insulin. When oocytes maintained in a paraffin oil medium were brought into contact with a 0.5 m̈I droplet of buffer containing the Mg2+ indicator dye, mag‐fura‐2, and pervanadate, apparent droplet Mg2+ decreased rapidly, indicating net uptake by the cells. Insulin also caused a net uptake of Mg2+. In contrast, apparent extracellular Mg2+ was constant when cells were in contact with droplets containing no effectors. Together, these data indicate that extracellular Mg2+, but not Ca2+, is involved in the stimulation of protein synthesis by pervanadate, and to a lesser extent by insulin. Pervanadate appears to induce a net uptake of Mg2+, and this change in membrane transport may be an early event in signalling the increase in translation. © 1995 Wiley‐Liss, Inc.