bluuebunny/crossref_metadata_2025_split huggingface dataset:
Systematic analysis of the ability of stromal cell lines derived from different murine adult tissues to support maintenance of hematopoietic stem cells in vitro
Authors: Rios Maribel , Williams David A. 
Published: February 2005

AbstractHematopoietic stem cells interact with a complex microenvironment both in vivo and in vitro. In association with this microenvironment, murine stem cells are maintained in vitro for several months. Fibroblast‐like stromal cells appear to be important components of the microenvironment, since several laboratories have demonstrated that cloned stromal cell lines support hematopoiesis in vitro. The importance of the tissue of origin of such cell lines remains unknown, since systematic generation of stromal cell lines from adult tissues has never been accomplished. In addition, the capacity of stromal cell lines to support reconstituting stem cell has not been examined. We have previously described an efficient and rapid method for the immortalization of primary bone marrow stromal cell lines (Williams et al., Mol. Cell. Biol. 8:3864–3871, 1988) which can be used to systematically derive cell lines from multiple tissues of the adult mouse. Here we report the immortalization of primary murine lung, kidney, skin, and bone marrow stromal cells using a recombinant retrovirus vector (U19‐5) containing the simian virus large T antigen (SV40 LT) and the neophosphotransferase gene. The interaction of these stromal cells with factor‐dependent cells Patterson‐Mix (FDCP‐Mix), colony forming units‐spleen (CFU‐S), and reconstituting hematopoi‐etic stem cells was studied in order to analyze the ability of such lines to support multipotent stem cells in vitro. These studies revealed that stromal cell lines from these diverse tissues were morphologically and phenotypically similar and that they quantitatively bound CFU‐S and FDCP‐Mix cells equally well. However, only those cell lines derived from bone marrow‐supported maintenance of day 12 CFU‐S in vitro. One lung‐derived stromal cell line, ULU‐3, supported the survival of day 8 CFU‐S, but not the more primitive CFU‐S12. A bone marrow‐derived stromal cell line, U2, supported the survival of long‐term reconstituting stem cells for up to 3 weeks in vitro as assayed by reconstitution 1 year post‐transplant. These studies suggest that adherence of HSC to stromal cells is necessary but not sufficient for maintenance of these stem cell populations and that bone marrow provides specific signals relating to hematopoietic stem cell survival and proliferation.
Response to epidermal growth factor of skin fibroblasts from donors of varying age is modulated by the extracellular matrix
Authors: Colige A. , Nusgens B. , Lapiere C. M. 
Published: February 2005

AbstractThe present study was undertaken to investigate the effect of epidermal growth factor(EGF) on the biosynthetic activity of skin fibroblasts from donors of varying age and the modulation of their response to this growth factor by culture in a three‐dimensional extracellular matrix. When cultured in monolayeron plastic or at the surface of a collagen gel, EGF specifically inhibited collagen synthesis whatever the age of the donor (from 17 to 84 years, n = 11). This inhibition was paralleled by a significant decrease in the steady‐state level of procollagen type I mRNAs. When embedded in a three‐dimensional floating collagen lattice, EGF stimulated the non‐collagen protein (NCP) synthesis in fibroblasts from younger donors (5 out of 6) while fibroblasts from the older ones were not affected. Collagen production by fibroblasts from younger donors was not inhibited as in monolayer (some being even stimulated) while that of the older donors was inhibited as observed in monolayer. The steady‐state level of procollagen type I mRNA was not modified by EGF in the three‐dimensional culture. No significant difference was observed in the affinity and the number of EGF receptors of the fibroblasts on plastic or embedded in a collagen lattice between young and aged donors. Our results suggest that the environment of the cells can modulate the reactivity to EGF and reveal differences related to in vivo aging.
Diacylglycerols and PMA are particularly effective stimulators of fluid pinocytosis in human neutrophils
Authors: Keller H. U. 
Published: February 2005

AbstractDiacylglycerols (OAG, diC8) and PMA were found to stimulate fluid pinocytosis (net uptake of FITC‐dextran) to a far greater extent than other neutrophil activators, such as the chemotactic agents fNLPNTL and LTB4, the microtubule disassembling agents colchicine and nocodazole, the kinase inhibitor H‐7, or D2O. OAG and diC8 produce a dose‐dependent increase in the uptake of FITC‐dextran, which is up to about 25‐ to 30‐fold the control value of unstimulated neutrophils. The protein kinase inhibitor H‐7 alone had a small stimulating effect on the net uptake, and it failed to inhibit stimulation of fluid pinocytosis by PMA, OAG, and diC8. Also, the protein kinase inhibitor staurosporine failed to inhibit fluid pinocytosis stimulated by OAG, diC8, and PMA. Stimulated fluid pinocytosis and vacuolization in response to PMA or diacylglycerols is associated with surface ruffling of neutrophils. Pinocytosis as well as surface ruffling stimulated by PMA, OAG, diC8, or diC10 are suppressed in the presence of cytochalasin D. The results suggest that diacylglycerols may be instrumental in transducing the signal for stimulated pinocytosis and that the surface movements induced by diacylglycerols, and PMA may be instrumental in fluid pinocytosis.
Phagocytosis in Acanthamoeba: II. Soluble and insoluble mannose‐rich ligands stimulate phosphoinositide metabolism
Authors: Allen Philip G. , Dawidowicz Eliezar A. 
Published: February 2005

AbstractThe generation of second messengers during phagocytosis of yeast by Acan‐thamoeba castellanii was examined. The kinetics of binding and internalization of yeast by Acanthamoeba were measured and this was compared with the generation of known second messengers. We observed stimulated degradation of PI‐4, 5‐P2 to 1,4,5 IP3 with kinetics similar to that observed for the binding of yeast to amoeba. Similar production of IP3 could be induced upon treatment with a soluble mannosylated glycoprotein. We propose that the Acanthamoeba man‐nose receptor stimulates the degradation of PI‐4, 5‐P2 to 1,4,5 IP3 as an initial event in phagocytosis.
Complex mitogenic requirements of Na+ ‐K+ ‐Cl− ‐cotransport‐deficient BALB/c‐3T3 cells
Authors: Smyth Miriam J. , O'Brien Thomas G. , Wharton Walker 
Published: February 2005

AbstractThe ability of 12‐0‐tetradecanoylphorbol‐13‐acetate (TPA) to stimulate mitogenesis in BALB/c‐3T3 cells and in a Na+K+C1− ‐cotransport‐defective variant subclone was investigated. This transport variant had previously been reported to be TPA mitogenically nonresponsive (O'Brien and Prettyman: Journal of Cellular Physiology 130:377–381, 1987) since the addition of TPA to the spent medium of density‐arrested cultures stimulated DNA synthesis in the parent but not the variant cell line. We now report that the addition of TPA plus insulin, either directly to the spent medium or together with fresh medium, stimulated DNA synthesis in both the parent and variant cells to approximately the same extent. The parent and transport‐defective cells differed, however, in their sensitivity to the co‐mitogenic effects of insulin or insulin‐like growth factors.
Cloning of an osteoblastic cell line involved in the formation of osteoclast‐like cells
Authors: Yamashita Takeyoshi , Asano Katsuhiko , Takahashi Naoyuki , Akatsu Takuhiko , Udagawa Nobuyuki , Sasaki Takahisa , Martin T. John , Suda Tatsuo 
Published: February 2005

AbstractExperiments have been carried out to determine the mechanisms involved in the formation of osteoclast‐like cells from spleen cells in mice. Osteoclasts were defined as tartrate‐resistan. acid phosphatase‐positive multinucleated cells (TRACP‐positive MNCs) in which specific calcitonin receptors were identified by autdradiography with labeled salmon calcitonin. Furthermore, cultures rich in these cells produced resorption pits when grown on dentine slices. Several clonal cell lines were obtained from fetal mouse calvariae and screened for their ability to induce TRACP‐positive MNCs in response to 1α, 25‐dihydroxyvitamin D3 “1α,25(OH)2D3” in co‐cultures with spleen cells. A cell line, KS‐4, was identified with the greatest potency in inducing osteolast‐like cell formation in co‐culture with spleen cells. The capacity of KS‐4 cells to produce this effect was much greater than that of two bone marrow‐derived stromal cell lines (MC3T3‐G2/PA6 and ST2 cells), which we have previously shown to be effective in this system but to require treatment with dexamethasone in addition to 1α25(OH)2D3 (Udagawa et al.: Endocrinology 125:1805–1813, 1989). Parathyroid hormone (PTH) in creased cAMP production in KS‐4 cells, and PTH and interleukin‐1α also induced TRACP‐positive MNCs in co‐cultures with spleen cells. Contact between living KS‐4 and spleen cells was necessary for osteoclast formation to take place, since this did not occur when the two populations were separated by a membrane filter, or when the KS‐4 cells were killed by fixation. Separate cultures of either spleen cells or KS‐4 cells formed no TRACP‐positive MNCs. KS‐4 cells synthesized predominantly type I collagen, formed bone nodules without added of β‐glycerophosphate in a long‐term culture, and expressed increasing alkaline phosphatase activity after confluence in culture. These results indicate that the KS‐4 cells have properties consistent with progression toward the osteoblast phenotype, and represent a single cell line with the ability to promote osteoclast formation by a contact‐requiring process.
Antidiabetic AD4743 enhances adipocyte differentiation of 3T3 T mesenchymal stem cells
Authors: Sparks Rodney L. , Strauss Ethan E. , Zycmunt Andrea I. , Phelan Timothy E. 
Published: February 2005

AbstractAD4743 is an antidiabetic agent that, when added to fetal bovine serum (FBS), has been shown to have adipogenic activity for some proadipocyte cell lines once they reach confluence. In the current study, the effects of AD4743 on the growth and adipocytic differentiation of 3T3 T multipotential mesenchymal stem cells have been tested. 3T3 T cells, unlike other cells capable of undergoing adipocyte differentiation, are routinely induced to differentiate at low cell density. This is done using platelet‐poor human plasma (HP), a potent inducer of growth arrest and differentiation. AD4743 (0–200 μg/ml) was tested in varied concentrations of HP or FBS, at varied cell densities, and at various times during growth and differentiation. AD4743 slowed the growth rate of 3T3 T cells and it induced their differentiation in a dose‐dependent manner in medium containing 10% FBS once they reached confluence. Tiie data suggest that the ability of AD4743 to inhibit growth may also becoupled with its ability to enhance differentiation. In addition, AD4743 (1–10 μg/ml) in the presence of 25% HP markedly increased the kinetics of adipocyte differentiation, at low (< 5,000 cells/cm2) or high cell density. Greater than 50% cell differentiation could be achieved in 2 days in low density cultures; 80–95% differentiation could be achieved in just 4 days, compared to 8–12 days in a typical culture. The maximum amount of differentiation in HP was potentiated by AD4743 to agreater degree in poor lots of HP; however, the kinetics were increased in all lots. Adipocytic differentiation was measured both morphologically and by Northern blot analyses of differentiation‐specific genes. AD4743 at 1–10 μg/ml appeared to be most effective, depending on the cell density and other conditions. The mechanism of action of AD4743 remains to be elucidated, but the enhancement of adipocyte differentiation does not appear to occur via an insulin‐dependent pathway.
Distribution and comparison of receptors for leukemia inhibitory factor on murine hemopoietic and hepatic cells
Authors: Hilton Douglas J. , Nicola Nicos A. , Metcalf Donald 
Published: February 2005

AbstractLeukemia inhibitory factor (LIF) is a glycoprotein that induces the differentiation of the monocytic leukemia cell line M1 but suppresses the differentiation of totipotent embryonic stem cells. In an attempt to define the normal cellular targets for LIF, the distribution of LIF receptors within hemopoietic and hepatic tissue was analyzed by binding cells with radioiodinated LIF (125I‐LIF) and subsequently carrying out autoradiography. Autoradiography demonstrated that in each he‐mopoietic tissue examined cells of monocyte/macrophage lineage were the primary cell type labeled with 125I‐LIF. Moreover, both fetal and adult parenchy‐mal hepatocytes displayed higher levels of labeling than either monocytes or macrophages. The number of receptors per positive cell varied from 150 for bone marrow monocytes to 2,000 for adult hepatocytes. In each case, however, binding was of high affinity, with an apparent KD of 34–100 pM, and binding was specific, since labeling was competed for by unlabeled LIF but not a range of other structurally unrelated growth and differentiation factors. It is suggested that LIF may play a role in regulating macrophage function and hepatic acute phase protein synthesis in response to infection.
Control of the intracellular Ca2+‐concentration and the inositol phosphate accumulation in dog thyrocyte primary culture: Evidence for different kinetics of Ca2+‐phosphatidylinositol cascade activation and for involvement in the regulation of H2O2 production
Authors: Raspe E. , Laurent E. , Corvilain B. , Verjans B. , Erneux C. , Dumont J. E. 
Published: February 2005

AbstractCarbachol, through a muscarinic receptor, thyrotropin‐releasing hormone (TRH), prostaglandin F2α (PGF2α), bradykinin, and adenosine triphosphate (ATP) in creased the apparent [Ca2+], (intracellular free Ca2+ concentration) of dog thyrocytes in primary culture. The [Ca2+], measured by the Quin‐2 technique rose immediately after the addition of the agonists and reached a maximal value after less than 30 seconds. Afterwards, the [Ca2+], declined to a plateau higher than the basal level when the cells were triggered with carbachol. By contrast, in most experiments with PGF2α and in the case of bradykinin, TRH, and ATP, the [Ca2+], returned to the basal value. If the extracellular Ca2+ was chelated by excess of EGTA, the addition of all agents caused a sharp reduced transient rise in the [Ca2+], followed by a decline of the [Ca2+], often below the basal level (especially in the case of carbachol). It is suggested that the first transient phase of these responses is due at least in part to the mobilisation of Ca2+ from intracellular stores whereas the second sustained phase of the response to carbachol mainly originates from an increased Ca2+ influx into the thyrocytes.Carbachol, bradykinin, TRH, PGF2α, and ATP also increased generation of inositol phosphates in dog thyrocytes. This effect was sustained when the cells were triggered with carbachol and was more transient with bradykinin, TRH, PGF2α, or ATP.All these agents and the phorbdester TPA as well as forskolin enhanced to various extent the thyrocyte H2O2 generation. This enhancement was severely reduced in the absence of extracellular Ca2+ and was mimicked by Ca2+ ionophores in the presence of extracellular Ca2+ especially in synergy with protein kinase C activators. These data suggest that the dog thyrocyte H2 O2 generation, the limiting step of the thyroid hormone synthesis, is modulated by carbachol, TRH, PGF2α, bradykinin, and ATP through their action on the Ca2+‐phosphatidylinositol cascade.
Substrate‐associated macromolecules promote cytodifferentiation of BC3H1 myogenic cells
Authors: Strauch Arthur R. , Berman Mark D. , Miller Howard R. 
Published: February 2005

AbstractDifferentiated mouse BC3H1 myogenic cells secrete substrate‐associated macromolecules (SAM) which restrict the proliferation of undifferentiated cells and promote both cell shape changes and expression of predominantly the vascular smooth muscle (VSM)‐specific isoform of the contractile protein α‐actin. While we previously reported that high cell density was required for stimulating maximal expression of VSM α‐actin in BC3H1 cells (Strauch and Reeser: Journal of Biological Chemistry264:8345–8355, 1989), the permissive effect of SAM on myoblast cytodifferentiation was not at all dependent on the formation of cell to cell contacts. This observation suggests that biogenesis of an extracellular matrix rather than the formation of physical contacts between cells may be the rate‐limiting step for induction of VSM α‐actin expression at high cell density. The biologically active moieties in SAM that promote cytodifferentiation also are expressed by mouse embryonic fibroblast cell lines and are distinctly different from a class of adheron‐like macromolecules released by differentiated BC3H1 myocytes directly into the culture medium. While SAM was cell growth restrictive, reconstituted particulate material (RPM) prepared from myocyte‐conditioned medium promoted the adhesion and proliferation of growth‐arrested myoblasts. SAM and RPM are composed of different polypeptide subunits which collectively may establish microenvironmental conditions that are permissive for BC3H1 myogenic cell differentiation.
Hydrogen peroxide alters the physical state and function of the plasma membrane of pulmonary artery endothelial cells
Authors: Block Edward R. 
Published: February 2005

AbstractHydrogen peroxide (H2O2) is an important mediator of acute oxidative injury to vascular endothelium. Because the plasma membrane is the initial site of interaction between endothelial cells and extracellular H2O2 produced by stimulated neutrophils or macrophages, we evaluated the effect of H2O2 on the physical state, i.e., fluidity, and function of porcine pulmonary artery endothelial cell plasma membranes. Lactate dehydrogenase (LDH) release, 5‐hydroxytryptamine (5‐HT) uptake, limiting fluorescence anisotropy (r∞) for trimethylamino‐diphenylhexatriene (TMA‐DPH), and conjugated dienes were measured 0.5, 6, and 24 hr after cells were exposed for 30 min to 50‐μM H2O2 or Hanks' Balanced Salt Solution (control). Compared with control cells, H2O2 caused significant increases in LDH release and in 5‐HT uptake 6 hr after exposure. The increase in 5‐HT uptake was not blocked by imipramine. H2O2 also caused a significant increase in r∞ for TMA‐DPH 0.5 hr after exposure and a significant reduction in r∞ for TMA‐DPH 6 hr after exposure. Cellular contents of conjugated dienes were increased 0.5 and 6 hr after exposure to H2O2. Twenty‐four hours after exposute LDH release, r∞, 5‐HT uptake, and conjugated dienes had returned to control levels. Preincubation with 50‐μM α‐tocopherol (vitamin E) or 1‐mM or 10‐mM dimethylthiourea (DMTU) for 1 hr or 24 hr prevented endothelial cell injury, whereas addition of vitamin E or DMTU to the medium 1 hr or 3 hr after H2O2 exposure did not protect against injury. These results indicate that H2O2 causes significant damage to the plasma membrane of pulmonary artery endothelial cells in vitro, leading to alterations in fluidity and leakiness of the membrane. This injury is associated with membrane lipid peroxidation, is reversible, and can be prevented by pretreatment, but not by post‐treatment, with vitamin E or DMTU.
Immunolocalization of basic fibroblast growth factor during chicken cardiac development
Authors: Consigli Seth A. , Joseph‐Silverstein Jacquelyn 
Published: February 2005

AbstractBasic fibroblast growth factor (bFGF) has been identified in cultured cardiac myocytes as well as in myocardial tissue of both embryonic and adult organisms; bFGF has also been demonstrated to regulate proliferation and differentiation of these cells in culture. Such studies suggest a possible role for bFGF in cardiac myogenesis. In vitro studies using cultured endothelial and neurona cells also suggest that myocyte‐derived bFGF may be involved in the regulation of vascularization and/or innervation of the developing heart. We have generated a spatial and temporal map for bFGF in the developing chick heart using immu‐nohistochemical techniques and our monospecific polyclonal rabbit antihuman bFGF IgG. A progressive decrease in bFGF expression was seen in the highly trabeculated region of the ventricular myocardium, relative to the myocardium directly underlying the epicardial tissue, with increasing developmental age. bFGF expression was limited to the cytoplasm of cardiac myocytes; neither vascular endothelium nor smooth muscle contained anti‐bFGF immunoreactive material. A correlation between the temporal and spatial pattern of bFGF expression seen here, with the pattern of myocyte proliferation and differentiation reported by others, suggests a role for bFGF in the autocrine regulation of myocyte proliferation and differentiation.
Ferric‐salicylaldehyde isonicotinoyl hydrazone, a synthetic iron chelate, alleviates defective iron utilization by reticulocytes of the belgrade rat
Authors: Garrick Laura M. , Gniecko Kathleen , Hoke James E. , Al‐Nakeeb Attila , Ponka Prem , Garrick Michael D. 
Published: February 2005

AbstractThe Belgrade rat has a hypochromic, microcytic anemia inherited as an autosomal recessive mutation. Although transferrin binds normally to reticulocytes and internalizes normally, iron accumulation into cells and heme is much slower than normal. We have investigated the role of the transferrin cycle in this mutant by bypassing transferrin iron delivery with the iron chelate ferric salicylaldehyde isonicotinoyl hydrazone (Fe‐SIH). Fe‐SIH increases iron uptake into heme by Belgrade reticulocytes, restoring it almost to normal levels. This increase indicates that Fe‐SIH delivers iron to a step in iron utilization that is after the Belgrade defect. Depleting reticulocytes of transferrin did not alter these observations. Failure to achieve above normal rates of iron incorporation could indicate damage due to chronic intracellular iron deficiency. Also, iron delivery by Fe‐SIH restored globin synthesis to near‐normal levels in Belgrade reticulocytes. The rates of glycine incorporation into porphyrin and heme in Belgrade reticulocytes incubated with Fe2‐transferrin or Fe‐SIH paralleled the rates of iron incorporation into heme. These data are consistent with the concept that iron availability limits protoporphyrin formation in rat reticulocytes. The protoporphyrin used for heme synthesis is provided by de novo synthesis and not by a pool of pre‐existing protoporphyrin. The Belgrade defect occurs in the movement of iron from transferrin to a step prior to reduction to the ferrous state and insertion into heme. This defect diminishes the synthesis of heme and, consequently, that of protoporphyrin and globin.