bluuebunny/crossref_metadata_2025_split huggingface dataset:
Retinoic acid inhibits basement membrane protein biosynthesis while stimulating dome formation by madin darby canine kidney cells in hormonally defined serum‐free medium
Authors: Taub Mary 
Published: February 2005

AbstractThe effect of retinoic acid on basement membrane protein biosynthesis and dome formation by Madin Darby canine kidney cells was examined. Retinoic acid inhibited the biosynthesis of laminin, collagen IV, and heparan sulfate proteo‐glycan by confluent MDCK monolayers in a hormonally defined serum‐free medium. Retinoic acid inhibited laminin biosynthesis by as much as 70% after an 8 day incubation period. The inhibitory effect of retinoic acid on laminin biosynthesis preceded temporally the stimulatory effect of retinoic acid on dome formation. This observation is consistent with the existence of a causal relationship between these two phenomena. Not only did retinoic acid inhibit the biosynthesis of laminin, but in addition the biosynthesis of the cellular 67 kd laminin binding protein was inhibited.
Mechanism of control of trophoblast invasion in situ
Authors: Graham Charles H. , Lala Peeyush K. 
Published: February 2005

AbstractWe have previously shown that first trimester human trophoblast cells share in vitro invasive properties with malignant cells. In this study we show that the in situ control of trophoblast invasion is provided by the uterine microenvironment. Trophoblast cells were labeled with 125l‐deoxyuridine and examined for their ability to invade an epithelium‐free human amniotic membrane in vitro under various conditions. The degree of invasion was determined as the percentage of the radioactivity retained within the membrane. Conditioned media from first trimester human decidual cells (DCM) suppressed invasion of trophoblast cells in the amnion invasion assay. This suppression was prevented by addition of neutralizing anti‐TGF β antibody or neutralizing antibody to tissue inhibitor of metalloproteinases (TIMP‐1) to the DCM, and mimicked by TGFβ,. These antibodies also augmented invasion beyond control levels, suggesting that trophoblast cells may also produce these factors. A bioassay for TGFβ activity, measured by antiproliferative effect on the mink lung epithelial cell line Mv 1 Lu, revealed that decidual cells produced this factor only in the latent form, whereas the active form was produced by the trophoblast. A decrease in collagenase type IV activity in the conditioned media of trophoblast cultures was observed when TGFβ was added to these cultures. Removal of endogenous TGFβ in trophoblast cultures by addition of anti‐TGFβ antibody resulted in down‐regulation of TIMP message as determined by Northern analysis. These results indicate that (a) decidua‐derived (and to a minor extent trophoblast‐derived) TGFβ is the prime mediator in the control of invasion by first trimester trophoblast, the latent form of TGFβlikely being activated by trophoblast‐derived proteinases; (b) induction of TIMPby TGFβ in both trophoblast and decidua is the final pathway in this control.
Heat shock induces two distinct S6 protein kinase activities in quiescent mammalian fibroblasts
Authors: Jurivich Donald A. , Chung Jongkyeong , Blenis John 
Published: February 2005

AbstractThe regulation of S6 kinase activity was used to monitor perturbations of intracellular signaling activity during heat shock of quiescent murine and human fibroblasts. Previous reports on exponentially growing insect and plant cells had indicated that 40S ribosomal protein S6 is dephosphorylated during heat shock; thus inhibition of S6 kinase activity by heat shock was anticipated in NIH 3T3 fibroblasts and human cells (HeLa, diploid embryonic fibroblasts MRC‐5, and skin‐derived fibroblasts). Unexpectedly, two distinct S6 protein kinases were activated in quiescent fibroblasts after heat exposure. One of the enzymes was partially purified by sequential column chromatography and was determined to be equivalent to the enzyme activated by serum and other growth factors, referred to here as pp70‐S6 protein kinase. The other protein S6 kinase, pp90rsk, was identified by a specific immunoprecipitation assay. Monitoring both enzymatic activities during heat shock revealed a temporal pattern of activation that was reversed when compared to non‐stressed, mitogen‐stimulated cells. Finally, heat shock stimulated protein S6 phosphorylation in cultured, quiescent mammalian cells. These data demonstrate that specific protein kinases can be activated during heat shock, and that some early mitogenic signals may also participate in the response of cells to physiologic stress.
Apoptosis of murine BW 5147 thymoma cells induced by dexamethasone and γ‐irradiation
Authors: Kruman Inna I. , Matylevich Natalia P. , Beletsky Igor P. , Afanasyev Vladimir N. , Umansky Samuil R. 
Published: February 2005

AbstractThe mode and the kinetics of the death of T‐thymoma cells upon dexamethasone treatment and γ‐irradiation (10Gy) have been studied using flow cytometry and biochemical analysis. It has been shown that the hormone and γ‐irradiation induce cell death by apoptosis. In both cases the cells are initially blocked in G2/M and die only after overcoming the blockage and cytokinesis. A short exposure to dexamethasone results in a cytostatic effect, whereas a cytotoxic effect is absent. Reducing serum concentration to 2% causes more rapid death both following γ‐irradiation and dexamethasone. These results are discussed in relation to cell death and proliferation.
Secretion and biological actions of insulin‐like growth factor binding proteins in two human tumor‐derived cell lines in vitro
Authors: Camacho‐Hubner Cecilia , McCusker Robert H. , Clemmons David R. 
Published: February 2005

AbstractThe insulin‐like growth factors (IGFs) I and II are present in extracellular fluids associated with specific binding proteins (IGFBPs) that can modify their biologic actions. These studies were undertaken to determine which forms of IGFBP are secreted by endometrial carcinoma (HEC‐1B) and breast carcinoma (MDA‐231) cells, to characterize variables that control IGFBP secretion, and to study the effect of IGFBP‐1 and IGFBP‐2 on IGF‐I stimulated cell proliferation. Secreted IGFBPs were identified by ligand blotting and IGFBP‐1 was quantified using a specific radioimmunoassay (RIA). MDA‐231 cell conditioned media (CM) contained four (43,000, 39,000, 30,000 and 24,000 Mr) forms of IGFBP, and HEC‐1B cell CM contained three forms (39,000, 34,000 and 30,000 Mr). Immunoblotting showed that the 30,000 Mr form secreted by both cell types was IGFBP‐1. Likewise the 34,000 Mr band in HEC‐1B media reacted with IGFBP‐2 antiserum and the 39,000 and 43,000 Mr bands reacted with IGFBP‐3 antiserum.IGF‐I stimulated the secretion of IGFBP‐3 from both cell types and IGFBP‐2 from HEC‐1B cells but either decreased or caused no change in secretion of IGFBP‐1 and a 24,000 Mr form. In contrast, insulin inhibited the secretion of IGFBP‐1 but increased the secretion of the 24,000 Mr form. Compounds that elevate intracellular cAMP levels increased the secretion of IGFBP‐3, IGFBP‐1, and the 24,000 Mr form from both MDA‐231 and HEC‐1B cells.When sparse cultures of MDA‐231 cells were used, addition of IGF‐I caused a 24% increase in cell number after 48 hr. This mitogenic response was enhanced by the presence of recombinant human IGFBP‐1 (45% increase in cell number, P < 0.001). Bovine IGFBP‐2 did not potentiate IGF‐I stimulated cell proliferation.These findings show that two tumor cell lines secrete distinct forms of IGFBPs and that there is differential regulation of IGFBP secretion. At least one form secreted by both tumors may act as a positive autocrine modulator of IGF‐l's growth stimulating actions.
Effect of trifluoperazine on renal epitheloid madin‐darby canine kidney cells
Authors: Paulmichl M. , Wöll E. , Weiss H. , Waldegger S. , Lang F. 
Published: February 2005

AbstractFollowing exposure to a number of hormones, the cell membrane in Madin‐Darby Canine Kidney (MDCK) cells is hyperpolarized by increase of intracellular calcium activity. The present study has been performed to elucidate the possible role of calmodulin in the regulation of intracellular calcium activity and cell membrane potential. To this end trifluoperazine has been added during continuous recording of cell membrane potential or intracellular calcium. Trifluoperazine leads to a transient increase of intracellular calcium as well as a sustained hyperpolarization of the cell membrane by activation of calcium sensitive K+ channels. Half‐maximal effects are observed between 1 and 10 μmol/L trifluoperazine. A further calmodulin antagonist, chlorpromazine, (50 μmol/L), similarly hyperpolarizes the cell membrane. The effects of trifluoperazine are virtually abolished in the absence of extracellular calcium. Pretreatment of the cells with either pertussis toxin or phorbolester TPA does not interfere with the hyperpolarizing effect of trifluoperazine. In conclusion, calmodulin is apparently involved in the regulation of calcium transfer across the cell membrane but not in the stimulation of K+ channels by intracellular calcium.
Enhanced inhibition of tissue factor by the extended form of an endothelial cell glycoprotein (an extrinsic pathway inhibitor)
Authors: Colburn P. , Crabb J. W. , Buonassisi V. 
Published: February 2005

AbstractWe have identified, in the supernatant medium of cultured endothelial cells, an additional inhibitor of tissue factor that is eluted at higher salt concentrations during heparin‐Sepharose chromatography and is a much more potent inhibitor of the activation of the coagulation cascade than the species we studied earlier (Colburn and Buonassisi: In Vitro Cellular and Developmental Biology 24:1133‐1136, 1988). The inhibitor we described earlier has been shown to be functionally and immunologically identical to a rabbit plasma extrinsic pathway inhibitor, EPI (Warn‐Cramer et al.: Thrombosis Research 61:515–527, 1991). The new species (molecular mass, 47 kDa) is susceptible to proteolytic cleavage which results in a sharp reduction of its ability to inhibit tissue factor and an increase in electrophoretic mobility compatible with a molecular mass of 45 kDa, the same as that of the inhibitor reported earlier. Based on these data, we suggest that the new inhibitor yields, through proteolytic cleavage of an amino acid sequence of about 25 residues, the N‐glycansulfated compound previously described.
Differential expression of two classes of lck transcripts upon phorbol ester treatment of human leukemic T cells
Authors: Leung Stewart , Miyamoto Neil G. 
Published: February 2005

AbstractThe human lymphocyte‐specific tyrosine kinase gene, Ick, is transcribed from two distinct promoters, resulting in two classes of transcripts (type I and II) differing in their 5′ untranslated regions. The steady‐state levels of the type I and II Ick transcripts were measured in a variety of lymphoid and non‐lymphoid human tumor cell lines by S1 nuclease mapping and by a sensitive assay system using the polymerase chain reaction. Human thymocytes and all the leukemic T cell lines tested express both type I and II Ick transcripts, albeit at different relative levels. Peripheral blood T cells express mainly type II Ick transcripts, whereas two colonic carcinoma lines, COLO 201 and COLO 205, express exclusively type I Ick transcripts. Treatment of the leukemic T cell lines, P30/OKUBO and Jurkat, by the phorbol esters tetradecanoylphorbol acetate (TPA) or phorbol dibutyrate (PDB) results in the down‐regulation of the type I, and the up‐regulation of the type II, Ick transcript levels. The effect of PDB on the in vitro differentiation of Jurkat cells, and the expression of Ick transcripts, is reversible. The modulation of Ick transcript levels in TPA‐treated Jurkat cells is not due to differential RNA stability, suggesting that the two Ick promoters are utilized differentially during T cell differentiation. The leukemic T cell line, Jurkat, may thus serve as a model for the elucidation of molecular mechanisms that regulate Ick transcription and T cell differentiation.
Murine mast cell colony formation supported by IL‐3, IL‐4, and recombinant rat stem cell factor, ligand for c‐kit
Authors: Tsuji Kohichiro , Zsebo Krisztina M. , Ogawa Makio 
Published: February 2005

AbstractRecently, a novel cytokine designated stem cell factor (SCF) was isolated from medium conditioned by buffalo rat liver cells and proved to be the ligand for c‐kit. We have examined the effects of recombinant rat SCF alone and in various combinations with interleukin‐3 and interleukin‐4 on murine mast cell colony formation in methylcellulose culture. As a source of connective tissue‐type mast cells (CTMC), we used peritoneal mast cells. No individual factor supported colony formation by purified peritoneal mast cells. When cells were grown in combinations of two factors, significant mast cell colony growth was seen. When cells were grown in the presence of three factors, not only the number of colonies was increased but also the colonies were larger. Mast cells in these colonies contained safranin‐ and berberine sulfate‐positive cells, but the proportions of positive and negative cells varied depending on the factor combinations. We then examined the effects of these factors on proliferation of bone marrow‐derived mast cells (BMMC) by replating pooled mast cell colonies. As a single factor, only interleukin‐3 supported mast cell colony formation. Combinations of two of the three factors supported mast cell colony formation. However, the most impressive synergism was seen again with the combination of the three factors. Not only was the number of colonies increased, but there was a significant increase in size. These results indicate that SCF is an important factor for the proliferation of both CTMC and BMMC.
Enhancement by transforming growth factor‐β 1 (TGF‐β 1) of the proliferation of leukemic blast progenitors stimulated with IL‐3
Authors: Suzuki Toshiya , Bessho Masami , Hirashima Kunitake , Tohda Shuji , Nagata Kaoru , Morio Tomohiro , Imai Yasufumi , Nara Nobuo 
Published: February 2005

AbstractWe studied the effect of transforming growth factor‐beta 1(TGF‐β 1) on colony formation of leukemic blast progenitors from ten acute myeloblastic leukemia (AML) patients stimulated with granulocyte colony‐stimulating factor (G‐CSF), granulocyte‐macrophage colony‐stimulating factor (GM‐CSF), interleukin‐3 (IL‐3), interleukin‐6 (IL‐6), or interleukin‐1β (IL‐1β). These CSFs and interleukins by themselves stimulated the proliferation of leukemic blast progenitors without adding TGF‐β 1. G‐CSF, GM‐CSF, and IL‐3 stimulated blast colony formation in nine patients, IL‐6 stimulated it in five, and IL‐1β stimulated in four. TGF‐β 1 significantly reduced blast colony formation stimulated by G‐CSF, GM‐CSF, or IL‐6 in all patients. In contrast, TGF‐β 1 enhanced the stimulatory effect of IL‐3 on blast progenitors from three cases, while in the other seven patients TGF‐β 1 reduced blast colony formation in the presence of IL‐3. To study the mechanism by which TGF‐β 1 enhanced the stimulatory effect of IL‐3 on blast progenitors, we carried out the following experiments in the three patients in which it occurred. First, the media conditioned by leukemic cells in the presence of TGF‐β 1 stimulated the growth of leukemic blast progenitors, but such effect was completely abolished by anti‐IL‐1 β antibody. Second, the addition of IL‐1 β in the culture significantly enhanced the growth of blast progenitors stimulated with IL‐3. Third, leukemic cells of the two patients studied were revealed to secrete IL‐1 β and tumor necrosis factor‐α (TNF‐α) constitutively; the production by leukemic cells of IL‐1 β and TNF‐α was significantly promoted by TGF‐β 1. Furthermore, the growth enhancing effect of TGF‐β 1 in the presence of IL‐3 was fully neutralized by anti‐IL‐1 β antibody. These findings suggest that TGF‐β 1 stimulated the growth of blast progenitors through the production and secretion of IL‐1 β by leukemic cells.
Differentiation induction of blast cells in two cases of childhood acute megakaryoblastic leukemia in vitro by interleukin‐3 and interleukin‐6: An ultrastructural cytochemical study
Authors: Miyauchi Jun , Sugita Kiyoko , Okui Masahito , Taguchi Nobuyuki , Clark Steven C. , Shimizu Koichi 
Published: February 2005

AbstractAlthough hematopoietic growth factors influence renewal and differentiation of blast progenitors in acute myelogenous leukemia (AML), morphological maturation of leukemic blasts is thought a rare event, even when cultured in the presence of appropriate growth stimulants. However, light microscopic observation may not be sufficient to clarify precisely the effects of hematopoietic growth factors on the morphological differentiation of leukemic blasts. In this study, using cell culture techniques and electron microscopic cytochemistry for platelet peroxidase (PPO), we studied the effects of interleukin‐3 (IL‐3) and interleukin‐6 (IL‐6), both of which are considered to play an important role in normal megakaryocytopoie‐sis, on the growth and differentiation of blast cells from two patients with childhood acute megakaryoblastic leukemia (AMKL). In both of the two cases, IL‐3 stimulated leukemic colony formation in methylcellulose culture, whereas IL‐6 showed little such activity. However, in suspension culture, IL‐6 was active in promoting megakaryocytic differentiation, although incomplete, as detected by increase in the number of PPO‐positive cells, some having demarcation membrane‐like structure. This effect was evident in culture with IL‐6 alone in one patient, but it was detectable only when IL‐6 was used in combination with IL‐3 in the other patient. In contrast, IL‐3 alone stimulated differentiation towards myeloid but not megakaryocytic lineage. These results indicate that IL‐3 and IL‐6 have a distinct role in leukemic megakaryocytopoiesis (IL‐3 stimulates growth, whereas IL‐6 promotes morphological differentiation) and that cooperation between these two cytokines functions most effectively for megakaryocytic differentiation of AMKL cells in a fashion similar to that for normal megakaryo‐cytopoiesis.
Correlation between the proliferative response to granulocyte colony‐stimulating factor and the positivity of transferrin receptor in acute myeloblastic leukemia cells
Authors: Motoji Toshiko , Mineshima Michio , Watanabe Masahiko , Takanashi Minoko , Masuda Michihiko , Oshimi Kazuo , Mizoguchi Hideaki 
Published: February 2005

AbstractThe use of granulocyte colony‐stimulating factor (G‐CSF) after chemotherapy for acute myeloblastic leukemia (AML) has been reported. However, there is a drawback in that G‐CSF may stimulate the proliferation of AML progenitors. To determine the parameter(s) indicative of responsiveness of AML blasts to G‐CSF, various surface phenotypes of blasts were examined in relation to the blast colony formation stimulated by G‐CSF in 39 AML patients. A correlation was found only with transferrin receptor positivity among the various phenotypes studied. The population mean of percentages of transferrin receptor‐positive blasts in the group responding to G‐CSF in vitro was significantly higher than that of blasts in the group not responding to G‐CSF. A further correlation was found between transferrin receptor positivity and the number of G‐CSF receptors on the blasts; that is, blasts expressing more G‐CSF receptors have greater transferrin receptor positivity. In our previous study, we observed that blasts with a large number of G‐CSF receptors produce more colonies in response to G‐CSF. These results indicated that blasts expressing more transferrin eceptors have a large number of G‐CSF receptors and may show more active proliferation in response to G‐CSF. Therefore, the proliferative response of blasts to G‐CSF can be predicted by examining transferrin receptor positivity. The clinical use of G‐CSF in AML patients may be recommended when the patient's blasts have a low level of transferrin receptor expression. The measurement of transferrin receptors on blasts, instead of the rather complicated G‐CSF receptor determination, would be a useful indicator for the safer application of G‐CSF in AML patients.
Erythroid lineage‐specific activity in conditioned medium derived from cloned human marrow stromal cells (CFU‐RF)
Authors: Aye M. T. , Izaguirre C. A. 
Published: February 2005

AbstractUsing long‐term culture techniques, it has been shown that stromal cells in the marrow microenvironment are essential for the continued production and self‐renewal of hematopoietic stem cells. We previously reported the development of a methylcellulose colony assay for a population of marrow stromal progenitors called CFU‐RF. In this paper, a method is described for subculturing cells from individual CFU‐RF‐derived colonies to allow conditioned medium production (StCM). StCM, prepared in this way, was found to possess an erythroid lineage‐specific activity that stimulated the formation of macroscopic erythroid colonies in cultures containing erythropoietin (epo). Using dose‐response curves, the KG1 colony assay, and antibody neutralization, it was shown that the activity could not be attributed to interleukin 3 (IL3) or granulocyte‐macrophage colony‐stimulating factor (GM‐CSF). However, it was further shown that a monolayer of stromal cells, which had earlier been producing the erythroid activity, could be stimulated by IL1 to produce granulocytic colony‐stimulating activity, but only as long as IL1 was present in the culture medium. These findings indicate a mechanism whereby the same stromal population could be modulated to promote growth and differentiation of different hematopoietic lineages.
Simultaneous occurrence of myelomonocytic leukemia and multiple myeloma: Involvement of common leukemic progenitors and their developmental abnormality of “lineage infidelity”
Authors: Akashi Koichi , Harada Mine , Shibuya Tsunefumi , Fukagawa Koji , Kimura Nobuhiro , Sagawa Kimitaka , Yoshikai Yasunobu , Teshima Takanori , Kikuchi Masahiro , Niho Yoshiyuki 
Published: February 2005

AbstractWe investigated the origin of leukemic progenitors in a case of the simultaneous occurrence of myelomonocytic leukemia and multiple myeloma (IgG‐K). At presentation, myeloperoxidase and nonspecific esterase‐positive myelomono‐cytic cells had proliferated up to 12.2 x 109/liter in the peripheral blood. Bone marrow cell differentials revealed the coexistence of myelomonocytic cells (30%) and atypical plasmacytoid cells (26%). Myelomonocytic cells in peripheral blood expressed both myeloid antigens (CD11b, CD13, CD14, CD15, CD33) and T/B‐lymphoid antigens (CD2, CD4, CD5, CD7, CD10, PCA‐1). Bone marrow mononuclear cells (BMMC) could be divided into PCA‐1 strongly positive and PCA‐1 weakly positive populations, which were considered to represent myeloma cells and myelomonocytic cells, respectively; the former were CD2‐positive (CD2+), CD14−, and CD15−, whereas the latter were CD2+, CD14+, and CD15+. Immunohistochemical analysis revealed that, in addition to plasmacy‐toid cells, a minority of myelomonocytic cells showed a positive reaction for IgG staining, and production of IgG was observed in the culture supernatant of CD14+ myelomonocytic cells in peripheral blood. Southern blot analysis revealed the presence of two identical rearrangement bands of immunoglobulin heavy chain gene in both BMMC containing myeloma cells and myelomonocytic cells and CD14+ myelomonocytic cells in peripheral blood. In a long‐term methylcellulose assay, peripheral blood mononuclear cells produced large compact colonies consisting of macrophages and IgG+ plasmacytoid cells (Mϕ/P colonies), while BMMC produced a different type of colonies consisting of CD14+ myelomono‐blasts, macrophages, and IgG+ plasma cells (Mb/Mϕ/P colonies) in addition to Mϕ/P colonies. Recloning experiments showed that primary Mb/Mϕ/P colonies gave rise to both secondary Mϕ/P and Mb/Mϕ/P colonies. These observations strongly suggest that common leukemic progenitors provide both myeloma and myelomonocytic leukemia cells, and the mechanism of “lineage infidelity” is probably involved in the development of their “bilineal” differentiation.