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  • General Chemistry  (5,879)
  • Cell & Developmental Biology  (5,677)
  • Limnology
  • 1985-1989  (10,313)
  • 1945-1949  (1,246)
Collection
Keywords
Publisher
Years
Year
  • 101
    Electronic Resource
    Electronic Resource
    Announcement (1989)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 13 (1989), S. 320-320 
    Details
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970130409
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  • 102
    Electronic Resource
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    What are the best host cells for expression of functional proteins for in vitro analysis? What are the vectors of choice for expression? What can we learn from site-specific mutagenesis coupled to in vitro studies on expressed proteins? (1989)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 14 (1989), S. 2-2 
    Details
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970140103
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  • 103
    Electronic Resource
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    Structure-function analysis of thin filament proteins expressed in Escherichia coli (1989)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 14 (1989), S. 12-20 
    Details
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970140105
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  • 104
    Electronic Resource
    Electronic Resource
    Bacterial expression of eukaryotic contractile proteins (1989)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 14 (1989), S. 3-11 
    Details
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970140104
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  • 105
    Electronic Resource
    Electronic Resource
    Expression of gelsolin by cos cell secretion (1989)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 14 (1989), S. 21-25 
    Details
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970140106
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  • 106
    Electronic Resource
    Electronic Resource
    Expression and mutation of Ca2+ ATPases of the sarcoplasmic reticulum (1989)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 14 (1989), S. 26-34 
    Details
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970140107
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  • 107
    Electronic Resource
    Electronic Resource
    Actin structure-function relationships in vitro using oligodeoxynucleotide-directed site-specific mutagenesis (1989)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 14 (1989), S. 35-39 
    Details
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970140108
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  • 108
    Electronic Resource
    Electronic Resource
    The yeast Saccharomyces cerevisiae as a model organism for the cytoskeleton and cellbiology (1989)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 14 (1989), S. 42-49 
    Details
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970140110
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  • 109
    Electronic Resource
    Electronic Resource
    A model for slow axonal transport and its application to neurofilamentous neuropathies (1989)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 12 (1989), S. 53-65 
    Details
    ISSN: 0886-1544
    Keywords: reversible binding ; computer simulation ; transport rates ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A model for slow axonal transport is developed in which the essential features are reversible binding of cytoskeletal elements and of soluble cytosolic proteins to each other and to motile elements such as actin microfilaments. Computer simulation of the equations of the model demonstrate that the model can account for many of the features of the SCa and SCb waves observed in pulse experiments. The model also provides a unified explanation for the increase and decrease of neurofilament transport rates observed in various toxicant-induced neuropathies.
    Additional Material: 7 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970120107
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  • 110
    Electronic Resource
    Electronic Resource
    225-Kilodalton phosphoprotein associated with mitotic centrosomes in sea urchin eggs (1989)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 12 (1989), S. 90-103 
    Details
    ISSN: 0886-1544
    Keywords: mitosis ; spindles ; microtubule-organizing centers ; antiphosphoprotein antibodies ; phosphorylation ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Protein phosphorylation during development of sea urchin eggs from fertilization to first cleavage was examined by labeling cells with specific antiphosphoprotein antibodies. Indirect immunofluorescence staining with monoclonal antithiophos-phoprotein antibody (Gerhart et al.: Cytobios 43:335-347, 1985) has revealed that nuclei as well as centrosomes, kinetochores, and midbodies were specifically thiophosphorylated in developing eggs incubated with adenosine 5′-O (3-thiotriphosphate) (ATP-γ-S). The phosphorylation reaction required Mg2+ but was not dependent on cAMP or calmodulin in detergent-extracted models. Centrosomes were purified by fractionation of isolated mitotic spindles with 0.5 M KCl extraction. The thiophosphoproteins were retained in the purified centrosomes and the antibody recognized a major 225-Kd polypeptide on immunoblots. In an independent preparation, a monoclonal antiphosphoprotein antibody (CHO3) was found also to react with mitotic poles and stained a 225-Kd polypeptide, confirming the centrosome specificity of this protein. Immunoelectron microscopy showed that the 225-Kd thiophosphoprotein was found at mitotic poles associated with granules to which mitotic microtubules were directly attached. Unlike centrosomes in permeabilized eggs, those in isolated spindles could not be thiophosphorylated, possibly due to inactivation or loss of either phosphorylation enzymes or cofactors, or both, during isolation. The immunofluorescence labeling of thiophosphate could be inhibited by ATP and AMP-PNP in a concentration-dependent manner. Exogenous ATP could abolish thiophosphate-staining more effectively when added with phosphatase inhibitors, suggesting a dynamic state in which centrosomal proteins are being phosphorylated and dephosphorylated in rapid succession by the action of protein kinase(s) and phosphatase(s).
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970120204
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  • 111
    Electronic Resource
    Electronic Resource
    Immunocytochemical studies of spectrin in hamster cardiac tissue (1989)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 12 (1989), S. 139-149 
    Details
    ISSN: 0886-1544
    Keywords: spectrin ; hamster ; cardiac tissue ; cytoskeletal-membrane ; myofibrils ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The spectrins are a family of cytoskeletal-membrane proteins that have a wide tissue distribution. In the present study, we employed polyclonal antibodies made against mammalian and avian erythroid spectrins as well as mammalian brain spectrin to assess their presence and distributions in the mammalian heart. Western blot analyses revealed that all three antibodies were specific for a 240,000 molecular weight α-spectrin subunit found in hamster erythrocyte ghost homogenates, whole hamster heart, and isolated hamster cardiac myofibril homogenates. Spectrin staining was absent from the Triton X-100-extracted supernatant fraction of myofibril preparations, suggesting that the protein is linked to the myofibril precipitate after exposure to the detergent. Frozen, unfixed, 2-μm-thick; sections of adult, Syrian golden hamster cardiac tissue exhibited strong immunofluorescent staining of intercalated discs and Z-bands using all three antibodies. In addition, the mammalian erythroid spectrin antibodies showed staining of the sarcolemma, and in cross section, revealed a delicate internal network of staining that appears to surround individual myofibrils. This may be T-tubule-associated staining. Myofibrils isolated from cardiac myocytes using Triton X-100 show positive Z-band staining using all three antibodies. Double staining with Texas Red-labeled monoclonal desmin and FITC-labeled polyclonal spectrin antibodies revealed that both stained the myofibrillar Z-line regions. These results demonstrate that spectrin is closely associated with the membranes, myofibrils, and intermediate filaments in the mammalian heart.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970120303
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  • 112
    Electronic Resource
    Electronic Resource
    Direct visualization of bipolar myosin filaments in stress fibers of cultured fibroblasts (1989)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 12 (1989), S. 150-156 
    Details
    ISSN: 0886-1544
    Keywords: stress fibers ; fibroblasts ; myosin ; bipolar filaments ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The authors examined the molecular organization of myosin in stress fibers (microfilament bundles) of cultured mouse embryo fibroblasts. To visualize the organization of myosin filaments in these cells, fibroblast cytoskeletons were treated with gelsolin-like protein from bovine brain (hereafter called brain gelsolin), which selectively disrupts actin filaments. As shown earlier [Verkhovsky et al., 1987], this treatment did not remove myosin from the stress fibers. The actin-free cytoskeletons then were lightly sonicated to loosen the packing of the remaining stress fiber components and fixed with glutaraldehyde.Electron microscopy of platinum replicas of these preparations revealed dumbbell-shaped structures of approximately 0.28 μm in length, which were identified as bipolar myosin filaments by using antibodies to fragments of myosin molecule (subfragment I and light meromyosin) and colloidal gold label. Bipolar filaments of myosin in actin-free cytoskeletons were often organized in chains and lattices formed by end-to-end contacts of individual filaments at their head-containing regions. Therefore, after extraction of actin, it was possible for the first time to display bipolar myosin filaments in the stress fibers of cultured cells.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970120304
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  • 113
    Electronic Resource
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    Differential localisation of tyrosinated, detyrosinated, and acetylated α-tubulins in neurites and growth cones of dorsal root ganglion neurons (1989)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 12 (1989), S. 273-282 
    Details
    ISSN: 0886-1544
    Keywords: cytoskeleton ; microtubules ; axons ; sensory neurons ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The comparative distribution of tyrosinated, detyrosinated, and acetylated α-tubulins was examined in neurites of rat dorsal root ganglion neurones in culture using immunofluorescence microscopy. Phase contrast observations of single neurones revealed that the neurites were actively motile, and rhodamine phalloidin staining of actin filaments showed the extent of lamellopodia and microspike projections from the growth cones. From double-labelling experiments using antibodies against tyrosinated, detryrosinated, or acetylated α-tubulin, it was found that the three different isoforms were differentially localised in neurites and growth cones. Detyrosinated and acetylated forms of α-tubulin were in the main restricted to the neurites extending no further than the base of the growth cones. Tyrosinated α-tubulin was, however, distributed throughout the body of the growth cone and into the base of some microspikes. Following treatment with taxol to promote microtubule assembly, detyrosinated and acetylated α-tubulins were found to be colocalised with tyrosinated α-tubulins throughout the growth cones of all cells examined. These results would be consistent with axonal transport of tyrosinated α-tubulin followed by assembly in the growth cone and subsequent detyrosination and acetylation. In addition the presence of unmodified α-tubulin in the growth cone may be necessary for the provision of labile microtubules for growth cone motility and extension.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970120408
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  • 114
    Electronic Resource
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    Masthead (1989)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 13 (1989) 
    Details
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970130101
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  • 115
    Electronic Resource
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    Antisense “Pseudogenetics” (1989)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 14 (1989), S. 81-91 
    Details
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970140117
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  • 116
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    How effective is antisense pseudogenetics as a method to eliminate a specific gene product from a cell? What are the advantages and disadvantages of this approach compared to gene targeting? (1989)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 14 (1989), S. 80-80 
    Details
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970140116
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  • 117
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    Molecular genetic approaches to the study of motility in Caenorhabditis elegans (1989)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 14 (1989), S. 136-145 
    Details
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970140123
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  • 118
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    Synthesis of mammalian profilin in Escherichia coli and Its characterization (1989)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 14 (1989), S. 230-236 
    Details
    ISSN: 0886-1544
    Keywords: profilactin ; actin ; cytoskeleton ; Trc promotor ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Profilin is a G-actin binding protein that may have a role in controlling the ratio of G/F actin within the cells To devise a way for obtaining large amounts of mammalian profilin in an active state, we transfected Escherichia coli with a plasmid containing a full-length rat spleen profilin cDNA adjacent to a promoter inducible by isopropyl thiogalactoside (IPTG). Upon induction, they synthesized a new protein of 15,000 MW constituting approximately 5% of the total cell protein. This protein bound to poly-L-proline Sepharose and could be eluted with 7 M urea, behavior similar to that exhibited by authentic profilin. The protein could be released from the bacteria in soluble form following sonication, and the profilin could then be purified to homogeneity following chromatography on Sephadex G-75 and DEAE A-50 Sephadex. The protein began with an unblocked Ala, indicating that the initiating formyl and methionine residues had been removed. The dissociation of the recombinant profilin from chicken skeletal muscle actin was characterized by a Kd of approximately 2 μM based on gel filtration analysis and actin polymerization assays. These results show that purified active mammalian profilin can be made conveniently in large quantities. This study also demonstrates the feasibility of using bacterially synthesized profilin in structure-function studies involving mutant profilins altered by site-directed mutagenesis.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970140209
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  • 119
    Electronic Resource
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    Acetylated α-tubulin in spermatogenic cells of the crane fly Nephrotoma suturalis: Kinetochore microtubules are selectively acetylated (1989)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 14 (1989), S. 237-250 
    Details
    ISSN: 0886-1544
    Keywords: mitosis ; spindle fibers ; cytoskeleton ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We studied the distribution of acetylated α-tubulin in the microtubules of spermatogenic cells from the crane fly Nephrotoma suturalis (Loew) using a mono-clonal antibody specific for acetylated α-tubulin (6-11B-1). We found that cells in all stages of spermatogenesis contained acetylated microtubules including primary spermatocytes, meiotic cells, spermatids, and sperm. A subset of the acety-lated microtubules (those in midbodies and flagella) were resistant to cold depolymerization. Newly polymerized microtubules in nondividing cells were not acetylated for up to 15 min. indicating that acetylation lagged behind polymerization. In spindles, newly polymerized microtubules were acetylated after 5 min. Antibodies to acetylated α-tubulin selectively stained chromosome-to-pole fibers in dividing cells, but the staining appeared to decrease and taper of at the kinetochores. This observation supports the hypothesis that tubulin subunits add at the kinetochore in metaphase and that acetylation occurs subsequent to addition. Further, this taper may be useful as a marker in anaphase, to distinguish between different hypotheses of chromosome motion.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970140210
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  • 120
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    Characterization of renatured profilin purified by urea elution from poly-L-proline agarose columns (1989)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 14 (1989), S. 251-262 
    Details
    ISSN: 0886-1544
    Keywords: Acanthamoeba ; affinity chromatography ; Dictyostelium ; NMR spectroscopy ; platelets ; myosin ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We present evidence that native profilin can be purified from cellular extracts of Acanthamoeba, Dictyostelium, and human platelets by affinity chromatography on poly-L-proline agarose. After applying cell extracts and washing the column with 3 M urea, homogeneous profilin is eluted by increasing the urea concentration to 6-8 M. Acanthamoeba profilin-I and profilin-II can subsequently be separated by cation exchange chromatography. The yield of Acanthamoeba profilin is twice that obtained by conventional methods. Several lines of evidence show that the profilins fully renature after removal of the urea by dialysis: (1) dialyzed Acanthamoeba and human profilins rebind quantitatively to poly-L-proline and bind to actin in the same way as native, conventionally purified profilin without urea treatment; (2) dialyzed profilins form 3-D crystals under the same conditions as native profilins; (3) dialyzed Acanthamoeba profilin-I has an NMR spectrum identical with that of native profilin-I; and (4) dialyzed human and Acanthamoeba profilins inhibit actin polymerization. We report the discovery of profilin in Dictyostelium cell extracts using the same method. Based on these observations we conclude that urea elution from poly-L-proline agarose followed by renaturation will be generally useful for preparing profilins from a wide variety of cells. Perhaps also of general use is the finding that either myosin-II or alpha-actinin in crude cell extracts, can be bound selectively to the poly-L-proline agarose column depending on the ionic conditions used to equilibrate the column. We have purified myosin-II from both Acanthamoeba and Dictyostelium cell extracts and alpha-actinin from Acanthamoeba cell extracts in the appropriate buffers. These proteins are retained as complexes with actin by the agarose and not by a specific interaction with poly-L-proline. They can be eluted by dissociating the complexes with ATP and separated from actin by gel filtration if necessary.
    Additional Material: 10 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970140211
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  • 121
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    Polymerization of additional actin is not required for capping of surface antigens in B-lymphocytes (1989)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 12 (1989), S. 23-32 
    Details
    ISSN: 0886-1544
    Keywords: surface immunoglobulin ; concanavalin A ; fodrin ; DNase inhibition ; FACS ; pyrene actin ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: CH12 is a murine B-cell lymphoma whose surface immunoglobulin (sIg) and concanavalin A (Con A) receptors patch and cap readily. Actin may be involved in CH12 patching and capping, since fodrin and F-actin collect under the cap, and cytochalasin D inhibits sIg capping. We have examined the state of the actin cytoskeleton during patching and capping. A wide range of concentrations of rabbit anti-mouse antibody (RAM) and Con A were used to patch or cap CH12 cells. G-actin was quantitated by DNase I inhibition, F-actin was quantitated by fluorescence-activated cell sorter analysis of fluorescent phalloidin staining, and actin nucleation sites were measured by pyrene actin polymerization. None of these methods detected any significant changes in actin when compared to control cells or untreated cells, leading us to conclude that increased actin polymerization is not necessary for capping to occur. The significance of these data to the membrane flow and cytoskeletal models of capping is discussed.
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    URL: http://dx.doi.org/10.1002/cm.970120104
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  • 122
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    Structure and function of the cytoskeleton in heliozoa: I. Mechanism of rapid axopodial contraction in Echinosphaerium (1989)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 14 (1989), S. 288-301 
    Details
    ISSN: 0886-1544
    Keywords: axopodium ; microtubules ; X-body ; receptor site ; contraction ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: In the heliozoan Echinosphaerium, rapid axopodial contraction often occurs during food capturing. In morphological studies, it has been considered that rapid contraction is caused by conformation is change of the X-body. We determined that reaction sites or receptors for anion exchange resin, which can induce rapid contraction, were located in every region of the axopodium. However, the probability of locating sites where contraction was induced was lower in the middle region than in the distal region of the axopodium. In cases in which contraction was not induced by resin placed in the middle region of the axopodium, so-called bead formation was induced instead. At the fine structural level, only granulated forms of the X-body were observed in this beading region. These results suggest that rapid contraction results from disassembly of axonemal microtubules and the simultaneous contraction of the X-body and that bead formation represents a stage when only the X-body contracts. Furthermore, effects of metabolic inhibitors and Ca2+ channel blockers revealed that contraction of the X-body did not depend on the supply of adenosine triphosphate, but on Ca2+ influx. Ultrastructural observations revealed that the mass of the granulated X-body was aggregated into the proximal region of the axopodium, suggesting that the X-body might be associated with the undercoat of axopodial membrane or the axonemal microtubules themselves.
    Additional Material: 14 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970140214
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  • 123
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    Talin dynamics in living microinjected nonmuscle cells (1989)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 14 (1989), S. 271-287 
    Details
    ISSN: 0886-1544
    Keywords: actin-membrane interaction ; adhesion plaque ; vinculin ; integrin ; fibroblasts ; epithelial cells ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: To investigate the role of talin in the anchoring of actin-containing stress fibers to the cell membrane of nonmuscle cells, a fluorescent analog of the adhesion plaque protein talin was developed, characterized, and microinjected into living cells. Purified chicken gizzard talin was covalently labeled with the fluorescent dye lissamine rhodamine B sulfonyl chloride. The fluorescently labeled protein was then chromatographed on Sephadex G-25 and DEAE-cellulose in order to remove free dye and denatured protein. The fluorescent talin was able to bind purified vinculin and was localized in adhesion plaques, membrane ruffles, microspikes, and polygonal networks in acetone-permeabilized nonmuscle cells. In cells that were double-stained with fluorescent talin and an affinity-purified anti-talin an-tibody, a one-to-one correspondence of adhesion plaque staining was seen. Living epithelial cells (PtK2) were microinjected during interphase with fluorescent talin. Computer-enhanced video microscopy was used to document adhesion plaque dynamics such as (1) changes in plaque shape, (2) alterations in plaque positions, and (3) the appearance, growth, and dissolution of plaques. In cells that were followed during mitosis, the adhesion plaques disappeared during cell rounding and then subsequently reappeared upon spreading of the two daughter cells. Treatment of microinjected cells with DMSO in order to disassemble stress fibers resulted in an altered localization of the fluorescent talin. Upon recovery of the cell from the drug, the talin was visualized in its characteristic submembraneous position. These results are the first to document the role and distribution of talin in dynamic processes occurring in living microinjected nonmuscle cells.
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    URL: http://dx.doi.org/10.1002/cm.970140213
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    Announcements (1989)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 14 (1989), S. 302-303 
    Details
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970140215
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    Functions of intermediate filaments (1989)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 14 (1989), S. 309-331 
    Details
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970140302
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    Reproductive capacity of sea urchin centrosomes without centrioles (1989)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 13 (1989), S. 264-273 
    Details
    ISSN: 0886-1544
    Keywords: microtubules ; microtubule organizing center ; mitosis ; monaster ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: For animal cells, the relative roles of the centrioles and the pericentriolar material (the cenrosomal microtubule organizing center) in controlling the precise doubling of the centrosome before mitosis have not been well defined. To this end we devised an experimental system that allowed us to characterize the capacity of the centrosomal microtubule organizing center to double regularly in the absence of centrioles. Sea urchin eggs were fertilized, stripped of their fertilization envelopes, and fragmented before syngamy. Those activated egg fragments containing just the female pronucleus assembled a monaster at first mitosis. A serial section ultrastructural analysis of such monasters revealed that the radially arrayed microtubules were organized by a hollow fenestrated sphere of electrondense material, of the same appearance as pericentriolar material, that was devoid of centrioles. We followed individual fragments with only a female pronucleus through at least three cell cycles and found that the monasters did not double between mitoses. The observation that fragments with only a male pronucleus repeatedly divided in a normal fashion indicates that the assembly and behavior of monasters were not artifacts of egg fragmentation. Our results demonstrate that the activity that controls the precise doubling of the centrosome before mitosis is distinct and experimentally separable from the centrosomal microtubule organizing center. Our observations also extend the correlation between the reproductive capacity of a centrosome and the number of centrioles it contains (G Sluder and CL Rieder, 1985a: J. Cell Biol. 100:887-896). For a cell that normally has centrioles, we show that a centrosome without centrioles does not reproduce between mitoses.
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    URL: http://dx.doi.org/10.1002/cm.970130405
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    Indirect immunofluorescence localization of ponticulin in motile cells (1989)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 13 (1989), S. 245-263 
    Details
    ISSN: 0886-1544
    Keywords: actin ; actin-binding protein ; plasma membranes ; cytoskeleton ; immunofluorescence microscopy ; cell motility ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Ponticulin is the major actin-binding integral glycoprotein in plasma membranes isolated from log-phase Dictyostelium discoideum amebae. As such, this protein appears to be an important link between the plasma membrane and actin filaments (Wuestehube and Luna: Journal of Cell Biology 105:1741-1751, 1987). In this study, indirect immunofluorescence microcopy was used to examine the distribution of ponticulin in randomly moving D. discoideum amebae and in amebae engaged in cell migration and phagocytosis. Ponticulin is distributed throughout the plasma membrane and also is present in intracellular vesicles associated with the microtubule-organizing center-Golgi complex adjacent to the nucleus. In aggreating amebae, ponticulin is concentrated in regions of lateral cell-cell contact and in arched regions of the plasma membrane. Ponticulin also is present, but not obviously enriched, in filopodia, in the actin-rich anterior end of polarized cells, and in detergent-insoluble cytoskeletons. In amebae engaged in phagocytosis of yeast, ponticulin is present but not enriched in phagocytic cups and is associated with intracellular vesicles around engulfed yeast. These results suggest that ponticulin is stably associated with actin filaments in certain regions of the plasma membrace and that the actin-binding activity of ponticulin may be tightly controlled.Indirect immupofluorescence microscopy and immunoblot analysis demonstrate that human polymorphonuclear leukocytes also contain a 17 kD protein that specifically cross-reacts with antibodies affinity-purified aganst D. discoideum ponticulin. As in D. discoideum, the mammalian 17 kD ponticulin-analog appears to be localized in plasma membrane and is evident in actin-rich cell extensions. These results indicate that ponticulin-mediated linkages between the plasma membrane and actin may be present in higher eukaryotic cells.
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    URL: http://dx.doi.org/10.1002/cm.970130404
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    The cytoskeleton of the naked green flagellate Spermatozopsis similis: Isolation, whole mount elecron microscopy, and preliminary biochemical and immunological characterization (1989)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 14 (1989), S. 552-561 
    Details
    ISSN: 0886-1544
    Keywords: Spermatozopsis ; flagellar roots ; rhizosyndesmos ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The cytoskeleton of the naked, biflagellate green alga Spermatozopsis similis Preisig & Melkonian was isolated by treatment of cells with Nonidet P-40 (0.1%) in lysis buffer (30 mM HEPES, 5 mM EGTA, 15 mM KCl, pH 7) and studied in detail by whole-mount electron microscopy. Isolated cytoskeletons retain the twisted shape of live cells and consist of the two axonemes, the basal apparatus with 4 microtubular and two fibrous roots, and 8-10 secondary cytoskeletal microtubules (SCMT's). The four microtubular flagellar roots differ in number of microtubules (two types with 2 or 5 microtubules, respectively), in their association with fibrous roots of the system I-type (two-stranded roots), in total length (two roots with an average of 4.5 μm and two roots with and average of 7.5 μm), and in length of individual root microtubules. Certain of the root microtubules and most of the SCMT's extend to the posterior end of the cell where they converge, terminate and are interconnected by a fibrous cap-like structure, the rhizosyndesmos. This novel structure consists of a network of 2 nm filaments that presumably lacks centrin as indicated by double immunofluorescence (anti-α-tubulin and anti-centrin) of isolated cytoskeletons. Two-dimensional gel electrophoresis of isolated, purified basal apparatuses of S. similis identifies among other proteins two isoforms of centrin and α- and β-tubulin as intrinsic components.
    Additional Material: 13 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970140412
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    Are there eukaryotic organisms other than yeast where specific genes can be targeted and thereby disrupted or replaced with high efficiency? What advantages are afforded by microorganisms as model systems? (1989)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 14 (1989), S. 40-41 
    Details
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970140109
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    A mammary-derived growth inhibitor (MDGI) related 70 kDa antigen identified in nuclei of mammary epithelial cells (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 138 (1989), S. 415-423 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The aim of the present study was to investigate the expression of the mammary derived growth inhibitor (MDGI) and the subcellular localization of MDGI related antigens in bovine mammary glands. Cell-free translation of poly (A+) = RNA, immunoprecipitation with rabbit anti-MDGI-antibodies, and estimation of the relative contents of MDGI by a radioimmunoassay in mammary tissue of different functional statess revealed that the 13 kDa MDGI was dramatically increased in terminally differentiated mammary tissue compared with the proliferating tissue from pregnant animals. To address the question of tissue localizationl, polyclonal anti-MDGI antibodies and antibodies directed aganist a sythetic peptide corresponding ot residues 69 to 78 of MDGI were used. Western blotting of tissue fractions revealed the cytosolic and microsomal localization of MDGI. Additionally, both types of antibodies a 70-kDa antigeninthe unclear fractionof differentiated mammary glands. Salt extraction and DNase I digestion of isolated unclei, as well as chromatin purification, indicated an association of the 70-kDa antigen with the chromatin. By means of the immunogold technique, MDGI-related antigens were localized within euchromatic unclear regions of epithelial cells in the intact differentiated mammary gland. The immunostaining was markedly diminished in the proliferating tissue. This finding raises the possibility that MDGI and the 70-kDa antigen influence cell proliferation by acting on geneexpression within the unclei of mammary glands.
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    URL: http://dx.doi.org/10.1002/jcp.1041380225
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    Metabolism of small RNAs in cultured human cells (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 138 (1989), S. 433-438 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: There are gaps in what is known about the metabolism of some mammalian small RNA species. Our present observations can be summarized as follows. The level of radiolabeled mature U1 RNA doubled between 2 and 24 hr of label chase, while that of all other small RNA species tested did not change. These results are compatible with the possibility that the nucleotide precursor pool for U1 RNA transcription may be partly segregated, or that there may be a second pathway of U1 RNA formation. Precursors of nucleolar U3 RNA were detected whose electrophoretic mobilities are equivalent to those of transcripts ∼ 14 and ∼ 8 nucleotides longer than the mature species, and which are apparently cytoplasmic. The ladder of U2 RNA precursors showed a gap, suggesting that some of the cleavages during U2 RNA processing are endonucleolytic. We detected an apparent U5 RNA precursor whose electrophoretic mobility is equivalent to that of a species ∼ 1 nucleotide longer than mature U5 RNA. There was a predominant band in the middle of the ladder of U4 RNA precursors (apparently ∼ 3 nucleotides longer than mature U4 RNA) which suggests that U4 RNA maturation may pause briefly at that intermediate. There are apparently two additional species of mature hY3 RNA, which are less abundant and are about 1 and 2 bases longer than the major hY3 RNA species. An apparent hY3 RNA precursor was detected, which may be ∼ 2-3 nucleotides longer than the main mature hY3 RNA species.
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    URL: http://dx.doi.org/10.1002/jcp.1041380227
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    Masthead (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 138 (1989) 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcp.1041380301
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    Continuous maintenance of transformed fibroblasts under reduced serum conditions: Utility as a model system for investigating growth factor-specific effects in nonquiescent cells (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 138 (1989), S. 450-458 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We report the continuous growth maintenance of untransformed and chemically transformed fibroblasts (AKR-2B, AKR-MCA cells) in low concentrations of serum (0.1% FBS). The cell lines established (AKR-0.1F, MCA-0.1F) proliferated at rates comparable to cells maintained under high serum conditions (10% FBS). Complete removal of serum from the cells did not induce quiescence. The MCA-0.1F cells were more similar to the untransformed AKR-2B fibroblasts in their morphology, saturation density, inability to form colonies under anchorage-independent conditions, steady-state level of c-myc expression, and kinetics of induction of c-myc in response to specific growth factors. This report demonstrates the utility of this cell line as anonquiescent model system for investigating growth factor-specific effects in serum-free, cycling cells. Addition of transforming growth factor-β (TGF-β) (5 ng/ml) to proliferating MCA-0.IF cells, in the absence of any serum, induced a multilayered growth pattern at confluency, similar to that of AKR-MCA cells maintained in 10% FBS. Other growth factors tested did not elicit this effect. The induction of this growth pattern by TGF-β was associated with a sustained induction of the c-myc proto-oncogene at con-fluency, but not with a restoration of anchorage-independent growth. The data suggest that TGF-β may play a role in the up-regulation of c-myc at confluency previously described for AKR-MCA cells maintained in 10% serum.
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    Effects of vanadate on tyrosine phosphorylation and the pattern of glycosaminoglycan synthesis in rabbit chondrocytes in culture (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 138 (1989), S. 484-492 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The present study examined the effects of high doses of vanadate on glycosami-noglycan (GAG) synthesis and tyrosine phosphorylation in rabbit chondrocytes in confluent cultures. Although 6 μM vanadate increased the incorporation of [3H] glucosamine into chondroitin sulfate proteoglycans twofold, 40-60 μM vanadate suppressed this incorporation fourfold. Although 6 μM vanadate had little effect on [3H] glucosamine incorporation into hyaluronate, 40-60 μM vanadate increased this incorporation threefold. Chemical analyses confirmed that the increase in ∥3H∥glucosamine incorporation into hyaluronate and the decrease in the incorporation into chondroitin sulfate proteoglycan correlated with increased hyaluronate content and decreased chondroitin sulfate content in the cell layers of vanadate-transformed cells. Chondrocytes exposed to 40-60 μM vanadaje became typically transformed spindlelike cells. Furthermore, vanadate, at 6 and 60 μM, increased the overall level of phosphotyrosine by 8- and 31-fold, respectively, and 60 μM vanadate enhanced phosphorylation of many phosphotyrosine-containing proteins. These observations suggest that vanadate induces transformation-associated changes in the pattern of GAG synthesis when it induces excess phosphorylation on tyrosine in chondrocyte proteins.
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    URL: http://dx.doi.org/10.1002/jcp.1041380307
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    Effects of temperature on the degradation and biliary secretion of asialoorosomucoid by the perfused rat liver: Evidence for two intracellular pathways (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 138 (1989), S. 555-560 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We have utilized the in situ perfused rat liver under nonrecirculating conditions to examine the effect of temperature on the metabolism and biliary secretion of [125I]-asialoorosomucid (ASOR). In this manner we were able to follow the fate of a single round of internalized ligand. In control livers perfused at 37°C, approximately 50% of [125I]-ASOR injected into the portal vein was extracted on first pass. Five minutes after the injection, radioactivity, which had been extracted initially, began to appear in the hepatic venous effluent. Within 25 min, 50% of the initially extracted radioactivity was released into the perfusion medium; the bulk of this radioactivity (〉95%) was soluble in trichloroacetic acid. In livers perfused at temperatures slightly less than 37°C (30-35°C), first-pass extraction of [125I]-ASOR was similar to that observed at 37°C. However, a severalfold decrease in the rate of release of radioactivity from the liver into the perfusion medium was noted at the lower perfusion temperatures; whereas greater than 50% of the initially extracted radioactivity was released within 30 min from livers perfused at 37°C, only 5% was released at 30°C. At the lower perfusion temperature, a larger proportion of the released radioactivity was acid precipit-able (24% vs. 5%). Some radioactivity also was recovered in the bile; of the total amount of radioactivity released from the liver in 30 min at 37°C, approximately 5% was directed into the bile. At lower temperatures of perfusion, a greater fraction of the radioactivity that was released from the liver was directed into the bile (20% at 30°C vs. 5% at 37°C). The data imply that the endosomal pathway to the lysosome is highly sensitive to slight reductions in temperature while the transcytotic route into bile is less sensitive. Lower temperatures might prolong the residence time of ASOR in the prelysosomal endosomal compartments, and thereby increase the likelihood that undegraded ligand will be returned to the blood or be missorted into bile.
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    URL: http://dx.doi.org/10.1002/jcp.1041380316
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    Effect of macrophages on the translocation of protein kinase C in concanavalin a-stimulated lymphocytes (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 138 (1989), S. 561-567 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The concanavalin A (Con A)-induced proliferation of lymph node lymphocytes is dependent on the presence of macrophages. When lymphocytes are depleted of macrophages, Con A is no longer mitogenic. Either 12-0-tetradecanoylphorbol-13-acetae (TPA), interleukin 1 (IL1), or macrophages in combination with Con A can restore proliferation. To establish where the proliferation process is blocked in the absence of macrophages, an early step in the signalling pathway, the activation of protein kinase C, was examined. It was found that although Con A caused translocation of protein kinase C from the cytosol to the membrane of lymph node cells, when the lymph node cells were depleted of macrophages and exposed to Con A, this translocation of protein kinase C did not occur. Instead, protein kinase C activity decreased in the membrane fraction and increased in the cytosol. On the other hand, TPA caused translocation of protein kinase C (PKC) from the cytosol to the membrane regardless of the presence of macrophages. However, the macrophage product, IL1, alone or in combination with Con A did not cause translocation of protein kinase C. In a reconstitution experiment, in which lymph node cells were depleted of macrophages and then macrophages were added back, the addition of Con A again lead to translocation of protein kinase C from the cytosol to the membrane. This combination also restored cell proliferation. Therefore, the Con A induced PKC translocation in T lymphocytes is macrophage mediated. TPA overcomes the macrophage requirement by directly activaing PKC, while IL1 appears to act at a different step in proliferation.
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    URL: http://dx.doi.org/10.1002/jcp.1041380317
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    Protein synthesis during induction of DNA replication in thyroid epithelial cells: Evidence for late markers of distinct mitogenic pathways (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 138 (1989), S. 568-578 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The synthesis of specific proteins has been investigated in primary cultures of dog thyroid epithelial cells, which can be induced to progress into G1 phase, in the presence of insulin, by different types of mitogens: thyrotropin (TSH) acting through cyclic adenosine monophosphate (cAMP), epidermal growth factor (EGF), 12-O-tetradecanoyl-phorbol-13-acetate (TPA), or 10% serum. EGF, TPA, or serum specifically induce [35S] methionine labeling of protein 1 (Mr ≈ 80,000). The effect of EGF on protein 1 labeling and DNA replication is dependent on insulin. The level of protein 1 labeling as well as that of DNA synthesis is higher when TSH or TSH + serum are added together with EGF. It peaks in mid-G1. TSH alone, in the presence of insulin, stimulates DNA replication without inducing protein 1 synthesis, which thus represents a cell-cycle-dependent event that is not obligatory in mitogenic activation through cyclic AMP. Among the eight proteins whose synthesis is stimulated by TSH, only the labeling of protein 7, molecular weight ratio (Mr ≈ 38,000), correlates with the DNA synthetic activity of the cells. The present authors identified protein 7 as cyclin/proliferating cell nuclear antigen (PCNA), the auxiliary protein of DNA polymerase-δ. The effect of TSH on cyclin synthesis is already detectable when most of the cells are in late G1, but its stimulation by EGF or EGF + serum is delayed and detected only after extending the labeling period to the S-phase. These data support the view that the cAMP-mediated mitogenic pathway remains partly distinct from the better known pathways induced by growth factors and tumor promoters, even at late stages of the G1-phase.
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    Ionic dependence of glycylsarcosine uptake by isolated chicken enterocytes (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 138 (1989), S. 579-585 
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    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Dipeptide transport was studied in chicken enterocytes and its properties compared with those of Na+-dependent sugar transport. Results showed that 1) isolated cells were capable of accumulating glycylsarcosine (Gly-Sar) against a concentration gradient (2.5- to 3.0-fold accumulation). This uptake was maximal at pH 6.0, and it was inhibited by Na+-free medium and by ouabaine; 2) uptake of Gly-Sar was not affected by methionine and was competitively inhibited by carnosine, with a Ki of 12 mM; 3) the protonophore FCCP inhibited both Gly-Sar and 3-oxy-methyl-D-glucose (3-OMG) uptake by the cells; 4) amiloride, a well-known inhibitor of the Na+/H+ exchanger system stimulated 3-OMG uptake and inhibited Gly-Sar uptake, its effects being greater at pH 7.4; 5) and monensine prevents the effects of amiloride on both sugar and dipeptide uptake. In summary, Gly-Sar uptake depends on extracellular Na+ in an indirect manner via its effect on H+ efflux, and it appears to be dependent on an inward H+ gradient.
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    Ultraviolet light-induced inhibition of small nuclear RNA synthesis (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 138 (1989), S. 586-592 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Two apparently distinct types of inhibition of the synthesis of U1, U2, U3, U4, and U5 small nuclear RNA, induced by ultraviolet (UV) radiation, have been described before: immediate and delayed. Our present observations can be summarized as follows: a) neither the immediate nor the delayed inhibition appear to be mediated by the formation of cyclobutane pyrimidine dimers, since they were not prevented by photoreactivating light, in ICR 2A frog cells; b) the inhibition of U1 RNA synthesis, monitored in HeLa cells within the first few minutes after irradiation, extrapolated to a substantial suppression at time zero of postirradiation cell incubation, providing further support for the proposal that the immediate inhibition is a reaction separate from the delayed UV light-induced inhibition of U1 RNA synthesis; c) the transition from the pattern of the immediate inhibition to that of the delayed inhibition (disappearance of the UV-resistant fraction of U1 RNA synthesis and increased rate of inhibition) occurred gradually, without an apparent threshold, within the first 2 hr of incubation after irradiation; and d) the incident UV dose that resulted in a 37% level of residual U1 RNA synthesis (D37) during the delayed inhibition was about 7 J/m2, with an apparent UV dose threshold, and was about 60 J/m2 for the immediate inhibition.
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    Alteration of microtubule physiology in hepatocytes by insulin (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 138 (1989), S. 603-610 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Incubation of primary cultures of rat hepatocytes with insulin caused an alteration in several parameters of microtubule physiology. There was a transient decrease in total cellular tubulin levels and, at the same time, an apparent stabilization of microtubule polymers which was also transient. The level of microtubule polymer, however, was not altered, which indicated that an insulin-inducible decrease in the level of nonpolymerized tubulin was responsible for the decrease in total cellular tubulin. These changes were followed by an increase in tubulin mRNA levels and, shortly thereafter, by an increase in tubulin protein synthesis. This study demonstrates that microtubule physiology in hepatocytes is modulated by insulin and, further, suggests a model by which insulin-induced changes in microtubule physiology may play a role in regulating other insulin responses.
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    URL: http://dx.doi.org/10.1002/jcp.1041380322
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    Interleukin 1 stimulates prostaglandin synthesis and cyclic AMP accumulation in Swiss 3T3 fibroblasts: Interactions between two second messenger systems (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 139 (1989), S. 29-33 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Biochemical events elicited by interleukin 1 (IL-1) were studied in Swiss 3T3 fibroblasts. One hour after its addition, IL-1 stimulated synthesis of prostaglandin E2 (PGE2), which continued to accumulate for 4 days. IL-1 also stimulated cAMP accumulation. Indomethacin blocked cAMP accumulation in response to IL-1, suggesting that PG2 was responsible for the increase. Addition of exogneous PGE2 to indomethacin-treated cells restored cAMP accumulation. IL-1 enhanced thymidine incorporation, and indomethacin attenuated responses to lower concentrations. Thus, PGE2 appeared to play a role in the ability of low concentrations of IL-1 to stimulate thymidine incorporation. PGE2 augmented thymidine incorporation by increasing cAMP accumulation because in the presence of indomethacin addition of exogenous cAMP enhanced thymidine incorporation in response to low concentrations of IL-1. Elevated cAMP further stimulated PGE2 synthesis. Thus, PGE2 and cAMP interacted to potentiate their mutual accumulation. In summary, IL-1 stimulates PGE2 synthesis. PGE2, in turn, stimulates cAMP accumulation which potentiates IL-1-stimulated PGE2 synthesis and thymidine incorporation.
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    URL: http://dx.doi.org/10.1002/jcp.1041390106
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    Relationship between changes in ploidy and stable cellular resistance to hydrogen peroxide (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 139 (1989), S. 592-598 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Stable hydrogen peroxide (H2O2)-resistant variants of the Chinese hamster ovary HA-1 line have been isolated by culturing cells in progressively increasing concentrations of H2O2 (〉200 days, in 50-800 μM H2O2). Increases in catalase activity in these variant cell lines were shown to correlate with increased H2O2 resistance. Stable (〉240 days) H2O2-resistant cell lines, seven quasidiploid (21-22 chromosomes/cell) and six quasitetraploid (40-44 chromosomes/cell) were clonally isolated from the 800 μM adapted H2O2-resistant variants which were heterogeneous with respect to ploidy. The H2O2 dose-modifying factors (DMFs) were 3, 5, 8, 13, 15, 26, and 27 for the seven quasidiploid cell lines, and 21, 32, 38, 40, 42, and 49 for the six quasitetraploid cell lines. The mean DMF was 14±10 for the former and 37±10 for the latter. Our data show that on the average the quasitetraploid cell lines were significantly more resistant to H2O2-mediated cell killing than the quasidiploid cell lines derived from the same mixed population of 800 μM H2O2-adapted cells. When catalase activities (k units/cell) of the HA-1 cells and three of the clonally derived cell lines (two quasidiploid and one quasitetraploid) were determined and plotted vs. H2O2-DMF, a positive linear correlation was obtained (correlation coefficient = 0.99). This result was further confirmed when immunoreactive catalase protein/cell was detected by Western blots. Our data show that chronic exposure of cells to H2O2 stress (800 μM) was accompanied by increases in quasitetraploid cells within the population. Quasitetraploid cell lines derived from this population demonstrated increased stable H2O2-resistance which may be related to stable increases in the expression of catalase.
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    URL: http://dx.doi.org/10.1002/jcp.1041390320
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    Regulation of levels of IL-1 mRNA in human fibroblasts (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 139 (1989), S. 610-616 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Interleukin-1 (IL-1) has a crucial role in host defenses, inflammatory processes, and tissue homeostasis. A wide variety of cells produce this protein in response to a number of extracellular stimuli including microorganisms, antigenic stimuli, and products from other cells. Regulation of IL-1 production at the molecular level is poorly understood. We studied expression, intracellular signals, and posttranscriptional regulation of IL-1 mRNA in human mesenchymal cells by using Northern blot analysis. Tumor necrosis factor alpha (TNFα) and activators of protein kinase C including 12-O-tetradecanoylphorbol-13-acetate (TPA) and teleocidin induced the accumulation of IL-1β mRNA in human fibroblasts (WI-38). Effect of TNFα was not blocked by inhibitors of either protein synthesis (cycloheximide) or protein kinase C activity. Accumulation of IL-1β mRNA was also increased by a calcium ionophore (A23187) and an inhibitor of the Na+/K+ pump (ouabain); both compounds are known to increase cytoplasmic levels of Ca++. Stability of IL-1β mRNA in fibroblasts exposed to TPA was more than fourfold greater than after fibroblasts were exposed to either TNFα or cycloheximide. This suggests that posttranscriptional stabilization of IL-1β mRNA is a major mechanism leading to accumulation of IL-1β mRNA after activation of PKC in fibroblasts. Fibroblasts did not express IL-1α mRNA after exposure to stimuli which induced the accumulation of IL-1β mRNA. In summary, several different pathways regulate levels of IL-1β mRNA in human mesenchymal cells.
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    URL: http://dx.doi.org/10.1002/jcp.1041390322
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    EGF and TGF-alpha are potent chemoattractants for endothelial cells and EGF-like peptides are present at sites of tissue regeneration (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 139 (1989), S. 617-623 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We report here that epidermal growth factor (EGF) isolated from male mouse salivary glands is active as a potent chemoattractant for a rat heart vascular endothelial cell line (RHEC). Human EGF and transforming growth factor-alpha (TGF-alpha) produced in Escherichia coli are also active as chemoattractants for these cells. The chemotactic response of the cells is induced by concentrations of murine EGF that ranged from 0.01 to 1.0 nM with similar specific activities for both the human EGF and TGF-alpha. Other growth factors such as fibroblast growth factor (FGF), TGF-beta, platelet-derived growth factor (PDGF), insulin, or IGF were not active as chemoattractants for these cells. The chemotactic response exhibited similar kinetics to those reported for connective tissue cells responding to PDGF (2-6 h) and required both RNA and protein synthesis. However, in contrast to NIH/3T3 cells responding to PDGF, the proliferating cultures of RHEC respond as well as growth-arrested cultures in the chemotaxis assay. In in vivo studies of connective tissue regeneration it appears that EGF-like factors are present in wound fluid collected from rats. Acid extracts of wound fluid contained a RHEC chemotactic activity that was neutralized with anti-EGF antisera. These studies indicate that EGF-like factors may function in vivo to control in part the angiogenic events that occur during tissue repair.
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    URL: http://dx.doi.org/10.1002/jcp.1041390323
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    Fura 2 analysis of cytosolic calcium regulation in elutriated rat gastric parietal cells (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 139 (1989), S. 632-640 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The calcium probe, Fura 2, is used to establish and partially characterize histamine-, carbachol- and forskolin-induced calcium transients in enriched parietal cell populations prepared by centrifugal elutriation of dispersed rat fundic mucosa cell isolates. The magnitude of the maximal carbachol response, which is blocked by atropine but not cimetidine, is nearly five times that of histamine or forskolin. Time to peak responses for carbachol, forskolin, and histamine are approximately 7, 17, and 28 sec, respectively. Carbachol-, histamine-, and forskolin-induced increases in Fura 2 fluorescence appear dependent upon extracellular calcium, since these responses are attentuated in low calcium media and blocked by EGTA in low-calcium media or by lanthanum in high- or low-calcium medium. Trifluoperazine and fenoctimine, at concentrations that inhibit secretion, have no effect on either carbachol- or histamine-induced increases in cytosolic calcium. Seven major calcium/EGTA-sensitive phosphopro-teins are identified by SDS-PAGE electrophoresis of ATP 32P-labeled cell sonicates. We conclude that cytosolic calcium in enriched rat gastric parietal cell populations is regulated by secretagogue receptor-controlled calcium channels. We postulate that these channels may be controlled by cyclic AMP-dependent phosphorylation, since neither changes in cyclic AMP nor calcium alone mediate the effects of secretagogues entirely, but the interplay between these two second-messenger systems potentiates the actions of these agents. The role of cytosolic calcium as a second messenger in secretagogue action appears similar to that of cyclic AMP in that a specific cellular concentration must be reached to initiate acid secretion.
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    URL: http://dx.doi.org/10.1002/jcp.1041390325
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    Evidence that alterations in small molecule permeability are involved in the Clostridium perfringens type a enterotoxin-lnduced inhibition of macromolecular synthesis in vero cells (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 140 (1989), S. 498-504 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The mechanism by which Clostridium perfringens enterotoxin (CPE) simultaneously inhibits RNA, DNA, and protein synthesis is unknown. In the current study the possible involvement of small molecule permeability alterations in CPE-induced inhibition of macromolecular synthesis was examined. Vero cells CPE-treated in minimal essential medium (MEM) completely ceased net precursor incorporation into RNA and protein within 15 minutes of CPE treatment. However, RNA and protein synthesis continued for at least 30 minutes in Vero cells CPE-treated in buffer (ICIB) approximating intracellular concentrations of most ions. Addition of intracellular concentrations of amino acids to ICIB (ICIB-AA) caused a further small but detectable increase in protein synthesis in CPE-treated cells. ICIB did not affect CPE-specific binding levels or rates. Similar small molecule permeability changes (i.e., 86Rb-release) were observed in cells CPE-treated in either ICIB or in Hanks' balanced salt solution. Collectively these findings suggest that CPE-treatment of cells in ICIB-AA ameliorates CPE-induced changes in intracellular concentrations of ions and amino acids and permits the continuation of RNA and protein synthesis. These results are consistent with and support the hypothesis that permeability alterations for small molecules are involved in the CPE-induced inhibition of precursor incorporation into macromolecules in Vero cells.
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    Oxygen gradients in CHO cells: Measurement and characterization by electron spin resonance (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 140 (1989), S. 505-511 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The concentration of oxygen within cells is important in many physiological and pathological processes, but such oxygen-dependent processes are generally studied as a function of the concentration of extracellular oxygen, due to a lack of suitable methods. Using a newly developed technique based on ESR spectroscopy, we show that respiration stimulation of a cell suspension can result in a significant difference between average intracellular and extracellular concentrations of oxygen. These results indicate that studies of oxygen-dependent phenomena in cells may require measurement of intracellular oxygen concentrations and imply that there are mechanisms in cells that restrict the free diffusion of oxygen.
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    Elastin repeat peptides as chemoattractants for bovine aortic endothelial cells (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 140 (1989), S. 512-518 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Cultured bovine aortic endothelial cells migrate toward a concentration gradient of repeating elastin peptides, specifically the repeating nonamers Gly-Phe-Gly-Val-Gly-Ala-Gly-Val-Pro and Gly-Leu-Gly-Val-Gly-Ala-Gly-Val-Pro and the repeating hexamer Val-Gly-Val-Ala-Pro-Gly. Dose-response experiments demonstrate that the peak of activity occurs at 8 × 10-8 M for the nonapeptides and 1 × 10-8 M for the hexapeptide. Checkerboard assays establish that the movement is chemotaxis and not chemokinesis. Because of the concentration difference in the responsiveness between the nonapeptide and the hexapeptide, the cells can differentiate between the two types of repeats. The positive control for the chemo-taxis studies was fibronectin.
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    Sequential expression of cell surface C3bi receptors during neutrophil locomotion (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 140 (1989), S. 519-523 
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    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Fluorescence microscopy has been used to study the cell surface distribution of the complement receptor for C3bi (CR3) on human neutrophils during locomotion. CR3 is an integral membrane protein that participates in cell attachment phenomena including chemotaxis. Fluorescein- and rhodamine-conjugated monoclonal IgG or Fab fragments were used to label CR3. We have previously shown that CR3 is uniformly distributed on unstimulated cells. During cell locomotion the fluorescent labels redistribute to the uropod and retraction fibers. To better understand the role of CR3 in chemotaxis, we have performed sequential two-color labeling experiments in conjunction with fluorescence microscopy. Double-labeling experiments were conducted by labeling adherent neutrophils with fluorescein-conjugated anti-CR3 followed by chemotaxis in a gradient of FMLP (10-7 M). The cells were then labeled again with rhodamine-conjugated anti-CR3. The uropod and distal training filopodia were labeled with fluorescein, whereas the cell body and occasionally proximal filopodia near the uropod were labeled with rhodamine. When neutrophils were fixed and permeabilized prior to the second CR3 labeling, the second fluorescent label was localized to a granule-like compartment(s), often near the lamellipodium. The results suggest a flow of CR3 from intracellular granules → lamellipodia and cell body → uropod → trailing filopodia during chemotaxis.
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    ATP-resistant variants of transformed mouse fibroblasts (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 140 (1989), S. 524-529 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Addition of ATP to cultures of transformed mouse fibroblasts, 3T6 cells, resulted in cell growth inhibition, whereas the growth of the non-transformed counterparts, 3T3 cells, was only slightly affected. The inhibition was found to be specific for adenine nucleotides, and concentration dependent. At relatively low concentrations (e.g., 0.1 mM) the effect of ATP was cytostatic, whereas at higher concentrations (e.g., 1.0 mM) a cytotoxic effect was exerted. ATP-resistant variants of 3T6 cells were selected by exposure of cultures to gradually elevated concentrations of ATP. The variants were found to resemble the non-transformed counterparts, 3T3 cells, more than the 3T6 parent cells, by the following criteria: ATP-induced alte rations in the membrane potential, changes in membrane permeability, cell growth inhibition, and colony formation on soft agar. The data indicate that long exposure of the transformed cells to external ATP results in redifferentiation and reduction in their tumorigenicity.
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    URL: http://dx.doi.org/10.1002/jcp.1041400318
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    Effects of platelet-derived growth factor on bone formation in vitro (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 140 (1989), S. 530-537 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Platelet-derived growth factor (PDGF) is a polypeptide found in a variety of tissues, including bone, where it could act as an autologous regulator of skeletal remodeling. Therefore, a recombinant B chain homodimer of human PDGF was studied for its effects on bone formation in cultured rat calvariae. PDGF at 10-100 ng/ml stimulated [3H]thymidine incorporation into DNA by up to sixfold and increased the DNA content and the number of colcemid-induced metaphase arrested cells. This effect was observed in the fibroblast and precursor cell-rich periosteum. As a result of its mitogenic actions, PDGF enhanced [3H]proline incorporation into collagen, an effect that was observed primarily in the osteoblast-rich central bone. The effect of PDGF was not specific for collagen since it also increased noncollagen protein synthesis. In addition, PDGF increased bone collagen degradation. PDGF and insulin-like growth factor (IGF) I had additive effects on calvarial DNA synthesis, but PDGF opposed the stimulatory effect of IGF I on collagen synthesis and IGF I prevented the PDGF effect on collagen degradation.In conclusion, PDGF stimulates calvarial DNA synthesis which causes an increased number of collagen-synthesizing cells, but PDGF also enhances bone collagen degradation.
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    URL: http://dx.doi.org/10.1002/jcp.1041400319
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    Heparin-derived oligosaccharides: Affinity for acidic fibroblast growth factor and effect on its growth-promoting activity for human endothelial cells (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 140 (1989), S. 538-548 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The minimal structural requirements for the interaction of heparin with acidic fibroblast growth factor (aFGF) were investigated. Oligosaccharides (tetra- to decasaccharides) obtained by nitrous acid depolymerisation of standard heparin were separated by affinity chromatography on Sepharose-immobilised aFGF. The shortest fragment retained by the affinity column at 0.2 M NaCl and eluted at 1 M NaCl was a “regular” hexasaccharide, a trimer of the most abundant disaccharide sequence in heparin. More complex octa- and decasaccharides were also retained by the column. The Oligosaccharides eluted by 1 M NaCI from the affinity column (“high-affinity” Oligosaccharides) and those washed from the column at 0.2 M NaCI (“low-affinity” Oligosaccharides) were compared for their capacity to protect aFGF from proteolysis and to potentiate its mitogenic activity. At a low ionic strength, all Oligosaccharides tested, except the “regular” disaccharide, protected aFGF againsttrypsin and collagenase digestion. At higher ionic strength (〉 0.2 M NaCI), only high-affinity Oligosaccharides showed a protective effect. The high-affinity oligosaccharides (hexa- to decasaccharides) potentiated the mitogenic activity of aFGF, as measured by [3H]thymidine incorporation into DNA of human fibroblasts. The effect of the oligosaccharides on human endothelial cell proliferation was more complex: inhibition of proliferation was observed in the presence of serum and low concentrations of aFGF (1-5 ng/ml) and potentiation in the presence of higher concentrations of aFGF. The potentiating effect increased as a function of molecular size of the heparin fragments and, for a given size, as a function of the anionic charge of the oligosaccharide. Our results suggest that inhibition of cell proliferation by heparin may result from interference with an autocrine basic FGF-like activity.
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    Rapid deformation of “passive” polymorphonuclear leukocytes: The effects of pentoxifylline (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 140 (1989), S. 549-557 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Entry times for spherical (no pseudopods) polymorphonuclear leukocytes (PMNs) into a 4 μm micropipet have been measured as a function of pipet suction pressure (2,500-20,000 dyn/cm2) and concentration of the drug pentoxifylline (PTX, 0.1-10.0 mM). For control cells (0 mM PTX), entry rates (reciprocal entry times) increased almost linearly with increasing suction pressure, indicating a Newtonian-like behavior. With incubation in PTX solutions, entry rate vs. suction pressure became increasingly non-linear, suggesting a shear-thinning effect for the dissipative structure. At a given suction pressure the rate of entry showed a dose-dependent increase with increasing PTX concentration, the effect being most pronounced at high suction pressures (20,000 dyn/cm2). Also, with increasing PTX concentration two other effects were observed: (i) there was a decreased incidence of cells that displayed pseudopodia, and (ii) there was an increased incidence of cells forming hernias and an increased streaming of cell cytoplasm during aspiration. The first observation points to a down-regulation of the cell's functional ability to “activate” in response to surface/chemical stimuli, and the second indicates that both the cortical and cytoskeletal networks are weakened either by disruption and/or reduction in density of the protein polymers. These observations are in line with other recently published experiments which suggest that the rheological effects of pentoxifylline on PMNs may be associated with the state of actin.
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    Both homodimeric isoforms of PDGF (AA and BB) have mitogenic and chemotactic activity and stimulate phosphoinositol turnover (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 140 (1989), S. 558-564 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Platelet-derived growth factor (PDGF) occurs as three dimeric isoforms, AA, BB, and AB, which were previously shown to bind to two receptors with different isoform-specificity, the A/B-type (binds all three isoforms) and the B-type (binds only PDGF-BB). Results from competition binding experiments with Swiss 3T3 cells suggest the existence of a third receptor type, which recognizes PDGF-AB and PDGF-BB. Furthermore, Swiss 3T3 cells and human dermal fibroblasts express different relative and absolute levels of these receptor types. In particular, Swiss 3T3 cells express 90,000 PDGF-AA binding sites (A/B-receptors) per cell, whereas human fibroblasts express only 20,000 A/B-receptors per cell. All three PDGF isoforms were tested in either cell type for their effect on DNA synthesis. PDGF-BB and PDGF-AA were also tested in Swiss 3T3 cells for their effect on inositol phospholipid metabolism and chemotaxis. Each isoform promoted all three processes dose-dependently, but there were differences in the maximum cellular responses elicited. These responses reflect the capacity of the cells to bind the individual isoforms. These results demonstrate that the previous distinctions in responsiveness to the different PDGF isoforms are primarily a consequence of the differences in the levels of surface expression of the various isoform-specific receptor types, rather than of the differences in the intrinsic activity of these isoforms. Furthermore, these results suggest that all types of PDGF receptors are capable of responding to their respective ligands by mediating phosphoinositide breakdown, chemotactic responses, and DNA synthesis. Whether they exhibit other functional differences remains to be seen.
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    Serum-free culture of normal human melanocytes: Growth kinetics and growth factor requirements (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 140 (1989), S. 565-576 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Normal human epidermal melanocytes were selectively propagated from mixed (keratinocyte-melanocyte) cultures and primary epidermal cell suspensions in serum-free medium, MCDB 153 containing insulin, bovine pituitary extract (BPE), phorbol-12-myristate-13-acetate (PMA), ethanolamine, phosphoethanolamine, and hydrocortisone. Neonatal foreskin melanocytes (NFMs) replicated more readily than adult melanocytes in culture. Early passage NFMs grown in serum-free medium exhibited a population generation time of 24-48 hours. NFMs assumed a less dendritic appearance and were less pigmented than adult melanocytes. PMA or other protein kinase C-activating phorbol esters significantly enhanced mitogenesis of NFMs; however, cAMP-elevating agents were not required for efficient replication of NFMs. Basic fibroblast growth factor (bFGF) was a potent mitogen for NFMs and replaced the requirement for BPE in the culture medium. NFMs expressed a single class of specific, high-affinity receptors for bFGF, exhibiting a Kd = 3 × 10-11 M and approximately 76,500 receptors/cell. Neither EGF nor TGF-α were mitogenic for NFMs, and TGF-β reversibly inhibited NFM growth. Rapidly growing, early passage NFMs were shown to have cell cycle times of 19.5, 7.5, and 9 hours for G1, S, and G2 /M phases of the cell cycle, respectively. Culture of NFMs to confluence or depletion of growth factors from the culture medium caused reversible, G1 phase-specific, cell cycle growth arrest. Senescence of NFMs was associated with irreversible growth arrest in the G1 phase after 40-45 population doublings in culture. Our data demonstrate that basal medium MCDB 153 can be supplemented with defined factors to cultivate selectively two major constituent cell types of the epidermis, the melanocyte and the keratinocyte.
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    Fibronectin and fibrinolysis are not required for fibrin gel contraction by human skin fibroblasts (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 140 (1989), S. 577-583 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Human skin fibroblasts contracted fibrin gels in a time- and cell-dependent manner. Under optimal conditions, gel contraction amounted to more than 50% in 2 hr. Fibronectin did not promote contraction, and fibrinolysis was not required for contraction, although gels contracted without serum or aprotinin were lysed. Before contraction, fibrin was present in loosely packed, randomly organized fibrils. After contraction, the fibrils were more densely packed and aligned in the plane of cell spreading. Cycloheximide treatment of fibroblasts inhibited gel contraction in serum-free medium but not in serum-containing medium. Fibronectin could not substitute for serum in overcoming the cycloheximide effect. Binding sites for fibrin were distributed randomly over the cells' surfaces based on electron microscopic observations. Often small groups of fibrils were localized in indentations at the cell surface. Finally, peptides containing the arg-gly-asp-ser sequence inhibited gel contraction.
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    Temperature-dependent oligomerization of hsp85 in vitro (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 140 (1989), S. 601-607 
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    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The failure of conventional subcellular fractionation methods to identify interactions between the bulk of hsp85 and other cellular structures suggested that critical stress protein interactions might be detectable only at elevated temperatures. This was confirmed by showing that incorporation of hsp85 and grp95 into sedimentanble complexes in Triton X-100 extracts of L929 cells increased progressively over the 30°C-43°C temperature range. Whereas several other proteins, including hsp 110 and hsp69, became sedimentable under these conditions, this effect required temperatures of ∼43°C and was only partially detergent-dependent. In contrast, hsp85 became sedimentable at temperatures as low as 33°C, and this effect was highly detergent-dependent. Temperature-dependent conversion of purified hsp85 to a sedimentable form was shown to result from limited oligomerization of the protein, which occurred in the presence of detergent. Since the detergent requirement could be met by a variety of compounds, including sphingosine, these findings suggest that hsp85 oligomerization may occur when intact cells are exposed to elevated temperature.
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    Masthead (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 141 (1989) 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcp.1041410101
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    Adenosine triphosphate, bradykinin, and thyrotropin-releasing hormone regulate the intracellular Ca2+ concentration and the 45Ca2+ efflux of human thyrocytes in primary culture (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 140 (1989), S. 608-614 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The hormonal stimulation of phospholipase C and the consequent activation of the Ca2+-phosphatidylinositol cascade in eukaryotic cells is associated with modifications of the [Ca2+] (intracellular Ca2+ concentration) which modulates cellular functions. In this study, these modifications were investigated in primary cultures of human thyroid cells.The mean apparent basal [Ca2+] of human thyrocytes measured using the intracellularly trapped fluorescent indicator Quin-2 was found to be 89°C 16 nM (n = 49). ATP and, to a lesser extent, ADP, but not AMP or adenosine, elicited a concentration-dependent biphasic rise in human thyrocytes [Ca2+] and increased their 45Ca2+ efflux. The first transient phase of the [Ca2+] rise induced by ATP was resistant to extracellular Ca2+ depletion, whereas the second sustained phase was abolished in these conditions. This suggests that although the first phase of this response involves a release of Ca2+ from intracellular stores, the second phase requires extracellular Ca2+ influx. The response of human thyro-cytes to analogs of ATP is compatible with a P2-purinergic effect of ATP on these cells. Bradykinin and TRH affected the human thyrocyte [Ca2+] and 45Ca2+ efflux similarly to ATP. The human thyrocyte [Ca2+] and the 45 Ca2+ efflux were not modified by carbachol, a nonhydrolyzable analog of acetylcholine.The present results suggest the presence of P2-purinergic receptors to ATP and of receptors to TRH and bradykinin on human follicular thyroid cells. They also confirm that the Ca2+-phosphatidylinositol cascade is present in these cells and suggest that this cascade is modulated by ATP, TRH, and bradykinin. As this cascade is involved in the regulation of protein iodination, and therefore of thyroid hormones synthesis, these agents might have an important role in the regulation of the thyroid function.
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    URL: http://dx.doi.org/10.1002/jcp.1041400328
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    RNA synthesis and stability in UV-irradiated and nonirradiated mouse L cells (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 141 (1989), S. 1-7 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: In mouse L cells, relatively low doses of UV light (e.g., about 35 J/m2) induced the rapid breakdown of the molecules of many RNA species transcribed shortly before irradiation. This included 28S, 18S, 5.8S, and 5S rRNA, U1, U2, U3, U4, and U5 small nuclear RNA, but not the main band of transfer RNAs or 7SL RNA. At higher UV doses, an RNA band that contains tRNAleu was also degraded rapidly after UV irradiation. RNA molecules synthesized long before irradiation (e.g., 22 h for small RNAs, 4 h for large rRNAs) were not affected. Our results suggest that the maturation and/or assembly into fully mature ribonucleoprotein particles of several small RNA species is not completed 4 h after transcription. The effect of UV radiation occurred in mouse L cells, but not in human HeLa or KB cells. In a previous report, L cells were transformed by DNA transfection with two mouse U1b RNA genes, named U1.1 and U1.2. We observed now that, in L cells transformed with the U1.2 gene, the ratio of radioactivity in the apparent U1b and U1a RNA precursors after 5 min of labeling was about 20 times higher than (a) this ratio in briefly labeled L cells that had been transformed with the U1.1 gene, and (b) the ratio of radioactive mature U1b and U1a RNA after 20 h of chase in L cells transformed with the U1.2 gene. These results suggest that very high levels of U1b RNA are transcribed from the exogenous U1.2 gene copies, followed by the rapid degradation of most of these transcripts.
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    URL: http://dx.doi.org/10.1002/jcp.1041410102
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    Transforming growth factor-beta and fibroblast growth factor act synergistically to inhibit collagen II synthesis through a mechanism involving regulatory DNA sequences (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 141 (1989), S. 8-15 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Transforming growth factor-beta (TGF-β) and fibroblast growth factor (FGF) are two growth factors that will modulate chondrocyte growth and matrix synthesis. Here we report that these two growth factors act in a synergistic fashion to suppress the synthesis of type II collagen by embryonic chicken sternal chondrocytes. Treatment of chondrocytes with 20 ng/ml TGF-β or 100 ng/ml FGF (acidic or basic) results in a 60-70% suppression of expression of the pro α1 chain of type II collagen. By comparison, when chondrocytes are exposed to a combination of 1 ng/ml TGF-β and 10 ng/ml FGF, a complete suppression of type II collagen synthesis was observed. Epidermal growth factor (EGF), platelet-derived growth factor (PDGF), or insulin-like growth factor-1 (IGF-1) produce no suppression of synthesis either individually or in combination with TGF-β. The decreased expression of the protein results from a decrease in the steady-state level of the mRNA transcript coding for type II procollagen, as indicated by a northern analysis. Finally, chondrocytes transfected with a plasmid carrying the CAT gene driven by the collagen II promoter/enhancer sequence displayed high levels of CAT activity when cultured in control media, but treatment of the cells with a combination of the two growth factors resulted in a dramatic reduction of CAT activity, indicating diminished promoter activity. These results suggest that both TGF-β and FGF can down-regulate transcription of the collagen II gene through regulatory DNA sequences in the promoter and/or enhancer region. In addition, the finding of synergy suggests that these two growth factors may act through different pathways.
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    URL: http://dx.doi.org/10.1002/jcp.1041410103
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    Modulation of growth of human carcinoma SW-13 cells by heparin and growth factors (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 141 (1989), S. 16-23 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: This study reports on the effects of heparin, basic and acidic fibroblast growth factors (bFGF and aFGF, respectively), and transforming growth factor type-e (TGFe) on the growth of a human adrenocortical carcinoma cell line, SW-13. Heparin has previously been shown to inhibit growth in several cell types, including smooth muscle cells, certain fibroblasts, and epithelial cells, and to modulate the effects of fibroblast growth factors. Whereas bFGF and aFGF bind tightly to heparin and elute from a heparin-Sepharose column with 2 M NaCl and 1.6 M NaCI, respectively, TGFe binds to heparin with lower affinity and can be eluted from heparin-Sepharose column with 0.5 M NaCI. TGFe is a polypeptide unrelated to FGF, is present in neoplastic and nonneoplastic tissues, and stimulates the growth of certain epithelial cells and fibroblasts in soft agar and monolayer. Since the growth of SW-13 cells is stimulated by TGFe and by bFGF, we hypothesized that heparin would inhibit the growth of SW-13 cells by binding to these growth factors and that the effects of heparin could be overcome with the addition of either growth factor. Our experiments confirmed that heparin inhibits the growth of SW-13 cells. A dose-dependent growth inhibition was observed in both monolayer and soft agar. The inhibition in monolayer was partially reversed upon heparin withdrawal. The effects of heparin in both monolayer and soft agar were at least partially overcome by TGFe and by basic or acidic FGF. Overall protein synthesis does not appear to be affected by heparin as measured by [35S]methionine uptake. In contrast, epidermal growth factor (EGF) and insulin-like growth factor I (IGF-I) were unable to overcome heparin-induced inhibition both in monolayer and in soft agar. Heparin also inhibited [3H]thymidine incorporation in AKR-2B and partially inhibited AKR-2B cell stimulation by TGFe; however, it further potentiated the already potent stimulation by bFGF. We propose that heparin, TGFe, bFGF, and aFGF modulate the growth of SW-13 cells and possibly of other epithelial cells in complex ways and that heparin-like substances present in the extracellular matrix play an important role in the control of epithelial growth.
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    Retinoic acid modulates dome formation by MDCK cells in defined medium (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 141 (1989), S. 24-32 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Retinoic acid dramatically increases the size of domes in confluent MDCK monolayers in a hormonally defined medium (medium K-1). After 4-5 days of retinoic acid treatment, enlarged domes began to appear in confluent MDCK monolayers. After 7days with 3 × 10-7 M retinoic acid, the majority of the domes in the monolayers were between 27 and 80 × 10-3 μ M2 in area, whereas in control medium the majority of the domes were between 0 and 9 × 10-3 μm2 in area. The dependence of the retinoic acid effect on prostaglandin E1 (PGE1) was examined. In normal MDCK cells, the effects of retinoic acid on dome size were observed only in medium K-1 supplemented with PGE1. This observation indicated that retinoic acid did not elicit its effects simply by stimulating PGE production. In contrast, in monolayers of PGE1-independent MDCK cells, retinoic acid treatment resulted in an increase in dome frequency even in medium K-1 lacking PGE1 This observation can be explained by the elevated cyclic adenosine monophosphate (cAMP) levels in these PGE1-independent MDCK cells. Dibutyryl cAMP-resistant MDCK cells, which normally do not form domes in medium K-1, were also studied. Remarkably, the dibutyryl cAMP-resistant MDCK cells were observed to form domes at a significant frequency when medium K-1 was supplemented with retinoic acid. However in medium K-1 lacking PGE1,an effect of retinoic acid on dome formation by dibutyryl cAMP-resistant MDCK monolayers was not observed. The inability of dibutyryl cAMP-resistant MDCK cells to form domes in medium K-1 has previously been attributed to their decreased cAMP-dependent protein kinase activity. The stimulatory effects of retinoic acid on dome formation may possibly be due to an increase in the activity of a particular cAMP-dependent protein kinase or activation of a separate pathway.
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    URL: http://dx.doi.org/10.1002/jcp.1041410105
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    Diacylglycerol and calcium induce rapid enhancement of A-system amino acid transport by independent mechanisms in human T-lymphocytes (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 141 (1989), S. 33-39 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Sn-1,2-diacylglycerols (DAG) and ionized-free calcium can act as intracellular second messengers for cell activation. Traditionally, T-lymphocyte activation is assessed by measurements of DNA synthesis or lymphokine production, but these responses require several days to occur and involve multiple intermediary regulatory steps. In contrast, we have found that T-lymphocytes demonstrate rapid enhancement of A-(alanine-favoring) system amino acid uptake when treated with DAG or ionomycin. A 30-40% increase in the initial velocity of uptake (vi) of the synthetic A-system specific amino acid, methylamino-isobutyric acid (MeAIB), was measured following 5 min of exposure to DAG or ionomycin. The vi was enhanced 60% from 12 to 19 μmol/liter cell water per min after 30 min exposure of T-cells to optimal concentrations of dioctanoylglycerol (30 μM), oleoylacetylglycerol (30 μM), or ionomycin (5 μM) (P 〈 .01 for each agent). A 50-fold excess of non-radioactive MeAIB inhibited 80% of [14C]MeAIB uptake in both unstimulated and stimulated cells, indicating that uptake remained largely carrier-mediated on treatment with these agents. Cycloheximide, 100 μg/ml, inhibited protein synthesis but did not block the A-system amino acid transport enhancement induced by DAG or ionomycin. The DAG-induced increase in the vi was blocked 40% with 100 μM H-7, an inhibitor of protein kinase C. H-7 treatment did not inhibit the ionomycin-induced A-system enhancement. A marked increase in cytoplasmic free calcium was measured when T-lymphocytes were exposed to ionomycin but not on DAG exposure, and the A-system effect of ionomycin but not DAG was blocked by extracellular EGTA. These data are compatible with two pathways for rapid enhancement of A-system amino acid uptake in T-lymphocytes. DAG stimulation is mediated via protein kinase C whereas ionomycin produces an A-system effect of similar magnitude independent of protein kinase C by an increase in cytoplasmic calcium.
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    Stimulation of cartilage-matrix proteoglycan synthesis by morphologically transformed chondrocytes grown in the presence of fibroblast growth factor and transforming growth factor-beta (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 138 (1989), S. 329-337 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The effects of transforming growth factor-beta (TGF-beta) on the synthesis of cartilage-matrix proteoglycan by cultured rabbit chondrocytes were examined. Rabbit chondrocytes were seeded at low density and exposed to a 1:1 mixture of Dulbecco's modified Eagle's medium and Ham's F-12 medium supplemented with 0.5% fetal bovine serum, 1% bovine serum albumin, 50μg/ml ascorbic acid, and 2 × 10-7 M hydrocortisone (Medium A). Various combinations of TGF-beta, insulin-like growth factor-l (IGF-I), and fibroblast growth factor (FGF) were also added to Medium A, and the chondrocytes were grown to confluency. Chondrocytes grown with TGF-beta or FGF alone became flat or fibroblastic, those grown with FGF and TGF-beta became very elongated and formed distinct foci, and those grown with FGF and IGF-I showed the spherical configuration characteristic of overtly differentiated chondrocytes. Nevertheless, the incorporation of 3H With glucosamine into the large, chondroitin sulfate proteoglycan synthesized by cultures with FGF and TGF-beta was similar to that in cells grown with FGF and IGF-I and five times that in cells cultured with FGF alone. The increases in incorporation of 3H reflected real increases in proteoglycan synthesis, because chemical analyses showed an increase in the accumulation of macromolecules containing uronic acid in cultures with FGF and TGF-beta or with FGF and IGF-I. However, FGF in combination with either TGF-beta or IGF-I had little effect on the incorporation of 3H into small proteoglycans or hyaluronic acid. These results indicate that chondrocytes morphologically transformed with TGF-beta and FGF fully express the differentiated proteoglycan phenotype rather than the transformed glycosaminoglycan phenotype.
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    URL: http://dx.doi.org/10.1002/jcp.1041380216
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    Analysis of the multiple 5′ and 3′ termini of poly(A) + and poly(A)- deficient thymidylate synthase mRNA in growth-stimulated mouse fibroblasts (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 138 (1989), S. 358-366 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Thymidylate synthase (TS) mRNA content increases about 20-fold when growth-stimulated mouse cells progress from the GO/G1 phase into the S phase of the cell cycle. Previous studies, using a cell line in which the TS gene is amplified (LU3-7), indicated that transcriptional initiation as well as polyadenylation of the mRNA occur at several locations in unsynchronized cells. In the present study, we have used S1 nuclease protection assays to analyze the possible significance of the multiple transcriptional initiation and polyadenylation sites. We found that the same pattern of 5′ and 3′ termini were detected with RNA isolated from the overproducing cells as with RNA isolated from the parental mouse 3T6 cell line, demonstrating that the heterogeneous termini are not a consequence of gene amplification. There was no change in the pattern of 5′ or 3′ termini with either cell line during the progression from G1 phase through S phase in serum-stimulated cells. Therefore, the increase in TS mRNA content is not the result of differential utilization of the various transcriptional initiation or polyadenylation sites. Analyses of poly(A)- deficient cytoplasmic TS RNA showed that the 5′ termini were the same as those found in poly(A)+ mRNA. However, the 3′ termini were extremely heterogeneous in length. Although some of the poly(A)- deficient RNA extended beyond the normal site of polyadenylation, most of it was shorter than full-length TS mRNA.
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    URL: http://dx.doi.org/10.1002/jcp.1041380219
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    Differences of Ca2+ regulation in skin fibroblasts from blacks and whites (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 138 (1989), S. 367-374 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Black people have a higher propensity than caucasions toward essential hypertension. To explore the possibility that this racial difference relates to cellular Ca2+ metabolism, we measured 45Ca2+ washout and uptake and cytosolic free concentration of Ca2+ [Ca2+], in serially passed skin fibroblasts from normotensive black and white males. Depending on the experimental conditions, 45Ca2+ washout in these cells was described by either two or three exponential functions, whereas 45Ca2+ uptake was described only by a two-exponent function. There were no racial differences in 45Ca2+ uptake and washout of unstimulated fibroblasts. However, stimulation by human serum resulted in an increase in the 45Ca2+ washout that was higher in fibroblasts from blacks than from whites. The racial differences were expressed primarily by higher values of the apparent washout rate constant (k1) of 45Ca2+ from the largest and most rapidly exchangeable cellular pool. The effect of human serum was not related to its origin (blacks vs. whites). In 2 mM Ca2+ medium and 10% serum from blacks, the respective k1 (mean ± SEM; × 10-2/min) values for fibroblasts from blacks and whites were 89.68 ± 5.23 and 73.29 ± 4.0; in the presence of 10% serum from whites, the k1 values for cells from blacks and whites were 84.14 ± 2.80 and 76.36 ± 3.23 (overall significance of P .01). In Ca2+-deficient medium in the presence of 10% human serum, the k1 for fibroblasts from blacks and whites were 115.57 ± 3.76 and 102.15 ± 3.30 (P 〈 .05). Serum substantially increased the 45Ca2+ uptake in fibroblasts from both blacks and whites; however, racial differences were not observed. Basal levels of [Ca2+], were not different in fibroblasts of blacks vs. whites (46.8 ± 6.8 and 43.2 ± 7.1 nM for blacks and whites, respectively). However, the peak response of Ca2+ transients for cell stimulated by 5% human serum was significantly higher in blacks than whites (blacks = 963 ± 213, whites = 481 ± 162 nM; P = .0286). We conclude that Ca2+ regulation is different in serum-stimulated fibroblasts from blacks and whites and that, at least in part, this difference may relate to a greater agonist-induced mobilization of Ca2+ in fibroblasts from blacks.
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    Identification of a 15,000-molecular-weight form of immunoreactive transforming growth factor α in extracts of porcine pituitary (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 138 (1989), S. 393-404 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Two different mitogenic activities were identified from extracts of porcine pituitary by using COMMA-D mouse mammary epithelial cells in a serum-free 3H-thymidine incorporation assay. Porcine pituitaries were extracted in phosphate-buffered saline (pH 7.4) and 25-80% (NH4)2SO4 pellets were dialyzed and chromatographed by using DEAE-Sepharose Chromatography (pH 8.0), resulting in two peaks (I and II) of mitogenic activity. Peak I represented a recovery of 73% of the units of mitogenic activity present in crude extract of pituitary while only 1.25% of the activity was recovered in peak I was further purified by using CM-Sephadex and heparin-Sepharose chromatographies and yieled a mitogen that was able to elicit one-half-maximal stimulation of 3H-thymidine incorporation by COMM-D cells at 48 pg/ml. As expected with pituitary as the tissue source, peak I was confirmed to be basic fibroblast growth factor (bFGF) by using specific antibodies in enzyme-linked immunosorbent assay and Western immunoblotting pocedures. Peak II was futher purified by using chromatorofocusing (pH 7.3-5.0), reverse-phase, and action-exchange HPLCs. The mitogenic activity eluted at pH 6.3 from chromatofocusing, migrated as a 13-kDa molecule on gel filtration HPLC, and did not bind to heparin-Sepharose under conditions which bound fibroblast growth factors. The material purified from peak II and rat synthetic transforming growth factor α (TGFα) competed in a parallel fashion with 125I-epidermal growth factor for receptor binding with A431 human epidermal carcinoma cells. In addition, the mitogen purified from peak II showed a single immunoreactive band migrating at 15 kDa when specific antiserum against TGfα was used in a Western immunoblotting procedure. The data suggest that in addition to the well-documented presence of bFGF, normal adult porcine pituitaries contain a 15-kDa form of immunoreactive TGFα that binds to EGF receptors and is mitogenic for mammary epithelial cells.
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    URL: http://dx.doi.org/10.1002/jcp.1041380223
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    Effects of five recombinant hematopoietic growth factors on enriched human erythroid progenitors in serum-replaced cultures (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 138 (1989), S. 617-623 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Erythroid progenitors from normal human marrow were purified by a two-step immune panning method permitting both the enrichment of erythroid progenitors (plating efficency up to 10%) and the separation of CFU-E from BFU-E. The purified erythroid progenitors were grown in serum-replaced conditions; in some experiments at an average of one cell per well. Human recombinant granulocytemacrophage colony stimulating factor (GM-CSF), interleukin 3 (IL3), erythroid potentiating activity (EPA), and human erythropoietin (Epo) either recombinant or homogenous native were tested for their effect on CFU-E growth. Epo was an absolute requirement for CFU-E growth and was sufficient to obtain colony formation at the unicellular level whereas GM-CSF and IL3 did not further increase the plating efficiency. EPA potentiated the effect of Epo on this progenitor only in experiments performed at unicellular level. Human recombinant GM-CSF, IL3, Interleukin 1 α (IL 1α), and Epo were subsequently tested for their ability to promote BFU-E growth. GM-CSF and IL3 supported the growth of erythroid bursts in the presence of Epo, even at the unicellular level. However, IL3 promoted a higher number of bursts than GM-CSF under all conditions tested. These two growth factors have no or very small additive effects when tested in combination. IL1α added to Epo alone had no effect on the growth of BFU-E whereas it potentiated the combined action of IL3 and GM-CSF on the primitive BFU-E. In conclusion, this study confirms at the unicellular level and under serum-free conditions that erythroid progenitors are regulated by multipotential growth factors in early phases of erythropoiesis and become sensitive only to Epo in later phases of differentiation.
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    Effects of biaxial deformation on pulmonary artery endothelial cells (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 139 (1989), S. 492-500 
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    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: An apparatus has been designed to subject vascular cells grown on a compliant substrate in vitro to uniform, quantifiable levels of biaxial deformation. The system described can be controlled with respect to strain level, rate, and frequency to mimic the pulsatile force to which vascular cells are exposed in vivo under both physiologic and pathologic conditions. In the experiments presented here, bovine pulmonary artery endothelial cells were grown on a substrate of segmented polyurethane urea (MitrathaneTM). Cell growth and morphology on this substrate were compared with those of cells grown on standard tissue culture polystyrene with no difference noted between the two substrates. Primary cultures of pulmonary artery endothelial cells were seeded onto Mitrathane, which was then subjected to cyclic biaxial deformation-producing strains of 0.78%, 1.76%, 4.9%, or 12.5% at a frequency of 1 sec-1 and a duty cycle of 0.5 sec-1 for 7 h. Cells subjected to deformations generating strains of either 4.9% or 12.5% secreted significantly less fibronectin than nondeformed cells. Similar results were obtained in experiments using cloned pulmonary artery endothelial cells on Mitrathane subjected to the 4.9% strain; however, total protein synthesis was increased. Cell viability and DNA synthesis were not affected by cyclic biaxial deformation in these experiments.
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    URL: http://dx.doi.org/10.1002/jcp.1041390307
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    Effects of interleukin-1 on fibroblast extracellular matrix, using a 3-dimensional culture system (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 139 (1989), S. 501-508 
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    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: This study describes the alterations induced by Interleukin-1α and -β (IL-1α and IL-1β) on fibroblast-synthesized extracellular matrix. Fibroblasts were grown between pieces of dentin or in collagen-coated Terasaki wells for 3 or 6-9 weeks to create 3-dimensional cell-containing matrices constituted primarily of proteoglycans and collagens, respectively. Following incubation with IL-1α or IL-1β (10-9 M) at 37°C for 24 or 72 hr, samples were prepared for light and electron microscopy. Both IL-1α and IL-1β induced collapse of the extracellular matrix by 72 hr, as manifested by a decrease of the cross-sectional area and an increased density of the matrices. Three-week matrices were reduced 26% and 45% by using IL-1α and IL-1β, respectively. Comparable values obtained by using 6-week matrices were 14% and 30%. Cells within the matrix, normally stellate in shape with numerous extended processes, attained a more rounded or spindle shape with few and reduced processes and showed apparent alterations at cell matrix attachment sites and rearrangement of the cytoskeleton. Elongated cells at the top of the matrix appeared more compressed. The alterations were more pronounced in cultures incubated with IL-β than with IL-1α. Immunocytochemistry of extracellular matrix components revealed a decrease in staining intensity of chondroitin and dermatan sulfate in the 3-week matrix following IL-1β incubation. There was also a decrease in collagen type I staining of 9-week matrices treated with IL-1α or IL-1β. These studies show that IL-1 has an effect on fibroblast-synthesized extracellular matrix and indicate that the effects of IL-1α and IL-1β may differ. The resulting collapse of the matrix appears at least in part to be due to changes in proteoglycans and collagens.
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    URL: http://dx.doi.org/10.1002/jcp.1041390308
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    Differential inhibitory effects of TGF-β on EGF-, PDGF-, and HBGF-1-stimulated MG63 human osteosarcoma cell growth: Possible involvement of growth factor interactions at the receptor and postreceptor levels (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 139 (1989), S. 509-516 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The growth of MG63 human osteosarcoma cell line in 5% serum is stimulated by epidermal growth factor (EGF), platelet-derived growth factor (PDGF), or heparin-binding growth factor-1 (HBGF-1). The mitogenic effect of EGF and PDGF is completely blocked by TFG-β at 1 ng per ml and the effect of HBGF-1 is attenuated by 75-80%. Treatment of MG63 cells with TGF-β reduces HBGF-1 receptor binding affinity from 1.24 × 10-11 M to 3.51 × 10-11 M with no change on the receptor number (1.1. × 103 per cell). The receptor-binding affinity of EGF and PDGF is not altered by TGF-β treatment; however, the number of EGF receptor is increased by 25%. Both EGF and PDGF stimulate MG63 cellular tyrosine kinase activity, and such stimulation is inhibited by TGF-β pretreatment. No change in the cellular protein tyrosine phosphorylation pattern can be detected in HBGF-1-stimulated cells with and without TGF-β pretreatment. These data suggest that TGF-β inhibits EGF and PDGF mitogenicity by blocking EGF- and PDGF-stimulated tyrosine kinase activity and attenuates HBGF-1 mitogenicity by decreasing its receptor affinity.
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    Modulation of endothelial fibronectin synthesisby polymorphonuclear granulocytes (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 139 (1989), S. 517-523 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The attachment of polymorphonuclear granulocytes (PMNs) to vascular endothe-lial cells occurs continually in normal tissues; however, knowledge of the factors that control leukocyte margination is incomplete. In the present study, we used cell cultures of pulmonary artery endothelium to study their interaction with PMNs. Endothelial cells were seeded in Costar 24-well plates following which PMNs were inoculated onto the endothelial monolayers and incubated for 2 to 20 hours. During this period, fibronectin synthesis by endothelial cells was estimated by ELISA. In wells to which PMNs had been added, supernatant fibronectin concentration was increased at all time points during the 20 hour incubation. At 20 hours, supernatants from wells to which PMNs had been added contained approximately 2 1/2 times the control level of fibronectin. Since the amount of fibronectin, as determined by ELISA, adsorbed onto the added PMNs was negligible, these data suggest that PMNs can modulate the synthesis of fibronectin by pulmonary artery cells. Pulse labeling experiments and measurements of endothelial intracellular fibronectin also suggest this possibility. The endothelial response does not appear to be owing to nonspecific physical interaction since similarly sized polystyrene beads did not cause any change in supernatant fibronectin levels while glutaraldehyde-fixed PMNs caused only a 20-25% increase in fibronectin levels.
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    Epidermal growth factor stimulation of prostacyclin production by cultured aortic smooth muscle cells: Requirement for increased cellular calcium levels (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 139 (1989), S. 524-530 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We have examined the ability of epidermal growth factor (EGF) to regulate prostacyclin production by cultured A10 smooth muscle cells. EGF by itself had no effect on prostacyclin production, but it augmented the response to arg8-vasopressin. An EGF stimulation of prostacyclin production was also observed in the presence of the calcium ionophore A23187; it therefore seemed likely that the key event required for EGF to stimulate prostacyclin production might be an increase in the available cellular Ca2+. Studies with 45Ca2+ showed that vasopressin both mobilised Ca2+ from intracellular stores and increased the influx of extracellular Ca2+ into A10 cells. The increase in prostacyclin production caused by vasopressin and the augmentation by EGF were both abolished by TMB-8, an antagonist of Ca2+ mobilisation, by EGTA, a chelator of Ca2+ ions, or by incubating cultures in the absence of added Ca2+. These results were consistent with a central role for Ca2+ in the responses and showed that both intracellular and extracellular sources of Ca2+ were important for the triggering of prostacyclin production. The increases in prostacyclin production were only marginally affected by nifedipine, and no responses were seen (either in the absence or presence of EGF) when KCL was used to depolarise the cell membrane. These data indicated that uptake of Ca2+ ions via voltage-dependent channels was unlikely to be a major factor in the stimulation of prostanoid production. We conclude that the ability of EGF to stimulate prostacyclin production in A10 smooth muscle cells depends upon a concurrent stimulus that will increase available intracellular Ca2+ levels.
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    Interaction of serum and colony-stimulating factor for survival of a factor-dependent hemopoietic progenitor cell line (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 139 (1989), S. 531-537 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The growth, in vitro of the murine myeloid cell line FDC-P1 depends on the presenc of serum and a murine hemopoietic growth factor (either granulocyte/ macrophage colony-stimulating factor (GM-CSF) or multipotential colony-stimu-lating factor (multi-CSF, IL3)). To determine the differential roles of serum and colony-stimulating factor (CSF) during the growth of FDC-P1 cultures, we investigated the kinetics of proliferation and death after withdrawal of serum or CSF, using flow cytometry to quantitate the numbers of vital and dead cells. After withdrawal of CSF, the cells died without entering a quiescent state. The life span of cultures lacking CSF increased with increasing concentrations of serum (〉 50 h at 30% serum), and the cells kept dividing until they died. During the period of population death caused by the absence of CSF, the re-addition of CSF immediately prevented further cells from dying. After the withdrawal of serum in the presence of CSF, the cells continued to live and proliferate for weeks, but required high cell densities (〉〉 105/ml), which suggests that the cells produced an active substance that can substitute for serum. Serum as well as serum-free conditioned medium from dense cultures made the survival and growth of FDC-P1 cultures independent of cell density. Without sufficient quantities of this activity, all cells of the population died within an interval that was much shorter than one cell cycle, which indicates that the factor acts throughout most of the cell cycle. The results suggest that both the CSF and the serum factor act together to permit cell survival, rather than to drive proliferation.
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    Role of mevalonic acid in the regulation of natural killer cell cytotoxicity (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 139 (1989), S. 550-557 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Considerable evidence has accumulated for a role of a nonsteroidal mevalonate product in the regulation of DNA replication and cell division. We report here a similar requirement for mevalonate in a nonreplicative function, that of natural killer (NK) cell cytotoxicity. Treatment of NK cells with 10 μM compactin for 48 hr results in a significant inhibition of cytotoxicity which can be completely reversed by treatment with 1 mM mevalonate, but not cholesterol, dolichol, or isopentenyl adenine. Protein and RNA synthesis appear to be involved in this reversal. Treatment with compactin and reversal with mevalonate do not affect the phenotypic distribution of the effector cell population, and the cell type involved in the inhibition and reversal of cytotoxicity is a CD16 (Leu 11)-, Leu 19-positive, large granular lymphocyte. The conjugation of the target and effector cell early in the lytic pathway is inhibited by compactin treatment of the effector cell population, and this inhibition is reversed by mevalonate.
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    URL: http://dx.doi.org/10.1002/jcp.1041390314
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    Growth, enzyme activity, sugar transport, and hormone supplement responses in cells cloned from a pig kidney cell line LLC-PK1 (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 139 (1989), S. 538-549 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Three clones of the pig kidney cell line LLC-PK1 were isolated and characterized with regard to morphology, growth, proximal tubule enzyme activity, sugar uptake capacity, and hormone and drug responsiveness in a defined medium. Clone N4 was similar in morphology to the wild type (WT), whereas clone F8 showed loose attachment to the substrate, formed large, sweeping domes, and had an elongated desmosome junction between cells. The third clone, F2, did not form domes and showed a marked reduction in growth rate. Cultures of WT, N4, and F8 had higher specific activities of the enzymes alkaline phosphatase and γ-glutamyl transpeptidase at confluence relative to growing cells; however, there was no evidence of an increase in activity of either enzyme at confluence in F2. Phlorizin-sensitive α-methyl-D-glucoside uptake and cytochalasin B-sensitive 2-deoxy-D-glucose uptake were measured in confluent cultures grown on porous filter supports. None of the clones lacked either of the hexose transport systems, although quantitative differences were evident. N4 cells grown in a defined medium in 96-well culture plates were tested in situ for their enzyme responses to differentiation inducers, tumor promoters, and hormones. Alkaline phosphatase activity was significantly increased at confluence by serum, parathyroid hormone (PTH), and vasopressin (AVP), and was decreased by tetradecanoylphorbol acetate (TPA) and epinephrine (EPI). Glutamyl transpeptidase activity was decreased at confluence by serum, TPA, and EPI. Similar tests on α-methyl-D-glucoside uptake showed that serum, TPA, PTH, and AVP had no significant effect on phlorizin-sensitive uptake; however, calcitonin increased uptake by 84% (n = 18). It was concluded that LLC-PK1 clones maintained in a defined medium are useful models for studying renal cell function.
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    Second messenger function of phosphatidic acid in platelet activation (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 139 (1989), S. 558-564 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Phosphatidic acid (PA) is synthesized as the result of the receptor-mediated response of platelets to physiologic agonists. The role of PA in platelet signal transduction, however, is largely unknown. We have examined the responses of platelets to 1-stearoyl-2-arachidonoyl phosphatidic acid (SAPA), the predominant molecular species of human platelet PA. SAPA alone causes platelet aggregation, and pretreatment of platelets with SAPA markedly enhances thrombin-induced aggregation and secretion. Addition of SAPA to intact human platelets causes rapid breakdown of phosphatidylinositol-4,5-bisphosphate (PIP2) and the generation of diacylglycerol and endogenous PA. These reactions are associated with mobilization of intracellular calcium and activation of protein kinase C. SAPA also stimulates the release of endogenous arachidonic acid and its conversion to thromboxane A2. Furthermore, platelet activation by SAPA is blocked by indomethacin, indicating that the actions of SAPA are mediated by cyclooxygenase products. These findings suggest that SAPA may play an important role as an endogenous positive feedback signal to amplify receptor-mediated activation of PIP2-specific phospholipase C in human platelets.
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    URL: http://dx.doi.org/10.1002/jcp.1041390315
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    Effect of scatter factor on motility of epithelial cells and fibroblasts (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 139 (1989), S. 565-569 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The scatter factor is a protein released by fibroblasts that causes dispersal of epithelial cell colonies and disruption of intercellular junctions, as well as an alteration of morphology with ruffling and rapid extension and movement of pseudopodia. To find out if the scatter factor has a direct effect on cell migration, the Boyden chamber assay was used to determine the effect of partially purified factor on the migration of cells through 8 μm pore size filters. The results showed that the mobility of Madin-Darby canine kidney (MDCK) cells was stimulated, and usually maximal at 100 ng per ml, which is equivalent to 100 to 200 units of activity in the standard assay based on the morphology and arrangement of cells. The migration was due to chemotaxis and chemokinesis. A keratinocyte cell line was also sensitive as were, to a lesser extent, BSCI monkey kidney cells. The motility of freshly isolated fibroblasts and fibroblast cell lines, however, was not significantly affected. The results confirm the cell specificity and paracrine role of the scatter factor and show that this fibroblast-derived molecule can directly stimulate the movement of epithelial cells.
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    Electrophysiological properties of isolated rat liver cells (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 139 (1989), S. 580-585 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The electrophysiological properties of isolated rat liver cells were studied using the patch clamp method in whole-cell configuration. The membrane potential in isolated hepatocytes was -42 ± 17 mV (n = 20). The input resistance (Rin) and the time constant (τm) were 51 ± 17 M (the range of 34 to 180 MΩ) (n = 20) and 4.2 ± 1.0 msec (the range of 3 to 16.5 ms) (n = 20). Assuming that the specific membrane capacitance is 1 μF/cm2, the membrane resistance and membrane capacitance were 42. ± 9.0 KΩ cm2 and 87 ± 27 pF. These values indicate that isolated rat hepatocytes are not abnormally permeable or leaky. The current-voltage relationship was linear with no rectification. The depolarizing pulse from the resting potential did not induce fast or slow inward currents even when norepinephrine or high Ca2 (3.6 mM) were applied. This indicates that there is no voltage-sensitive Ca2+ channel in the isolated hepatocytes.
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    URL: http://dx.doi.org/10.1002/jcp.1041390318
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    Injury-induced release of basic fibroblast growth factor from bovine aortic endothelium (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 139 (1989), S. 570-579 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Although the basic fibroblast growth factor (bFGF) gene lacks a traditional consensus signal peptide domain indicative for secretion, many cell types have receptors for bFGF. Since endothelium is a rich source of cell-associated bFGF, we asked under what conditions could bFGF be released or secreted from confluent cultures of bovine aortic endothelial (BAE) cells. The level of bFGF in BAE cell lysates was compared with the level of heparin-releasable bFGF in intact BAE cell monolayers, intact cells with exposed extracellular matrix (nonlytic matrices), and extracellular matrices prepared by cell lysis (lytic matrices). Less than 10% of total cell-associated bFGF was released from intact cell monolayers and nonlytic matrices. In contrast, the levels of bFGF released from lytic matrices depended upon the conditions used to prepare the matrices. Cell lysis at neutral pH generated matrices that released the highest bFGF levels (approximately 50% of total cell-associated bFGF). These matrices were heavily contaminated by histones, indicating the cellular release and adsorption of intracellular proteins to the matrix. Matrices prepared by BAE cell exposure to basic pH (100 mM NH4OH) contained low bFGF content and minor histone contamination. These latter matrices were chosen to study bFGF sequestration, under physiological conditions, into the extracellular matrix of confluent BAE cell cultures. Incubation with endotoxin, an agent acutely toxic to BAE cells, resulted in cellular release and adsorption of endogenous bFGF to cells and matrices, accompanied by histone deposition in the matrices. These results suggested that one mechanism for bFGF release from BAE cell monolayers was passive release induced by severe cell injury and/or cell lysis with secondary adsorption to the matrix.
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    Effect of Na+ flux inhibitors on induction of c-fos, c-myc, and ODC genes during cell cycle (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 140 (1989), S. 161-168 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The role of Na + transport systems in the mitogenic signal induced by growth factors was studied, and it was shown that two Na + transport systems contribute to the early increase in cytoplasmic Na + in response to serum growth factors, namely the amiloride-sensitive Na+/H + antiport and the bumetanide-sensitive Na + /K + /CI- cotransport. Bumetanide or amiloride, when added separately, inhibited part of the increase in cytoplasmic Na +, as a response to the addition of serum to quiescent BALB/c mouse 3T3 fibroblasts. Each drug also suppressed part of the stimulation of the ouabain-sensitive Rb + influx, which was controlled by intracellular Na +. However, when both drugs were added together with serum growth factors, a complete inhibition of the early increase in [Na +], and subsequently a complete blockage of Na + /K + pump stimulation was obtained.Amiloride or bumetanide, when added separately, only partially inhibited DNA synthesis induced by serum, 24% and 8% respectively. However, when both drugs were added together, at the time of serum addition to the quiescent cells, cell entry into S-phase was completely inhibited. To investigate the mode of cell-cycle inhibition, analysis was done of the possible role of early Na + fluxes in the mitogenic signal transduced from cell membrane receptors to the nucleus. The effects of the two drugs amiloride and bumetanide on induction of three genes-c-fos, c-myc, and ornithin decarboxylase (ODC)-was measured during cell transition through the G1-phase. Amiloride and bumetanide, when added separately or in combination, did not inhibit the induction of c-fos, c-myc, and ODC mRNAs. These results suggest that stimulation of Na+ fluxes by serum growth factors is essential for cell transition into the S-phase of cell cycle, but it plays no apparent role in the growth factor signal transduced from the cell surface to the interior of the cell, as manifested by c-fos, c-myc, and ODC genes induction.
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    Nonesterified fatty acid accumulation and release during heart muscle-cell (myocyte) injury: Modulation by extracellular “acceptor” (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 140 (1989), S. 150-160 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Long-chain nonesterified fatty acid (NEFA) accumulation in the heart muscle cell (myocyte) and NEFA release to the extracellular milieu are considered contributors to the pathogenesis of myocardial injury in a number of cardiovascular disease states. Reported here is a study of the factors which influence and control the interactions among NEFA formation, intracellular NEFA accumulation, and NEFA release to the extracellular compartment by the irreversibly injured myocyte. Under conditions of metabolic inhibition, neonatal rat myocytes in primary monolayer culture became virtually depleted of ATP within 8 h. The metabolically inhibited myocytes evidenced membrane phospholipid degradation and a resultant net accumulation of NEFA produced thereby in the extracellular medium. However, under conditions of nutrient deprivation, the injured myocytes retained the NEFA produced from phospholipid catabolism intracellularly and did not release it to the culture medium, although the extent of myocyte ATP depletion was the same as it had been from metabolic inhibition. Serum could elicit, in a concentration-dependent fashion, the quantitative release of NEFA from metabolically inhibited myocytes to the culture medium but did not influence the net production of NEFA by the injured cells. Similarly, NEFA release from nutrient-deprived myocytes incubated in serum-free, substrate-free medium or in physiological buffer could be induced by supplementing the medium or buffer with bovine serum albumin (BSA), and the extent of NEFA release, but not NEFA formation, was dependent upon the extracellular BSA concentration. No manipulations to media other than changing their serum content or supplementing them with BSA were found to influence the disposition of NEFA produced during phospholipid catabolism in the irreversibly injured, ATP-depleted myocyte. Therefore, although progressive metabolic compromise in the myocyte was correlated with increasing, net NEFA formation, the distribution of the NEFA between the intracellular and the extracellular compartments was not determined by the magnitude of ATP loss or by the nature or duration of at least two injury stimuli, metabolic inhibition and nutrient deprivation. Rather, the net release of NEFA from the ATP-depleted myocyte to the culture medium and the consequent reduction of intracellular myocyte NEFA overload were critically and causally dependent upon the presence and concentration of extracellular NEFA “acceptor.” The influence of acceptor on the mobilization of NEFA from the injured myocyte has implications regarding the use of NEFA release as an index of myocyte pathology and could serve to modify the progression and extent of myocardial injury in vivo.
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    Masthead (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 140 (1989) 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcp.1041400201
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    Extracellular matrix heparan sulfate proteoglycans modulate the mitogenic capacity of acidic fibroblast growth factor (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 140 (1989), S. 584-592 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Confluent cultures of human endothelial cells deposit into extracellular matrix (ECM) distinct heparan sulfate proteoglycans (HSPG) which modulate acidic fibroblast growth factor's (aFGF) ability to stimulate human endothelial cell mitogenic capacity. Extracellular matrix 35S-HSPG were isolated from cultures metabolically labelled with Na235SO4 by DEAE-Sepharose, Sepharose CL-4B, and aFGF-Affi-Gel 15 column chromatography and identified by resistance to chon-droitinase ABC and sensitivity to nitrous acid. Fifty to sixty percent of the 35S-HSPG deposited into ECM do not bind aFGF. The bound 35 S-HSGP (40-50% of the total counts applied) eluted from the aFGF-Affi-Gel column after the addition of buffer containing 2 M NaCI. aFGF-binding and aFGF-nonbinding 35S-HSPG were individually pooled and further purified by Sepharose CL-4B column chromatography. 35S-HSPG which bind aFGF, designated HSPGp, were 100-fold superior to heparin in augmenting the mitogenic efficacy of aFGF in sparse proliferating cultures. In contrast, however, 35S-HSPG, which did not bind aFGF, designated HSPG1, inhibited aFGF-stimulated proliferation in both sparse and subconfluent endothelial cell cultures. The majority of the biological activity of both aFGF-potentiating HSPGP and aFGF-inhibitory HSPG1 was contained in the glycosaminoglycan chains released by alkaline borohydride treatment of intact HSPGP or HSPG1, respectively. 3H-Core protein derived from HSPGP or HSPG1 contained only minor biological activity. The ability of heparitinase or hepnrinase (Flavobacterium heparinum) to abolish biological activity differed, depending upon the HSPG tested, also suggested that these are two distinct HSPGs.
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    Protein kinase C activation and down-regulation in relation to phorbol ester-induced differentiation of SH-SY5Y human neuroblastoma cells (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 140 (1989), S. 593-600 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The role of protein kinase C activation in changes in muscarinic receptor functions and in the appearance of biochemical properties characteristic of neuronal cells was studied in SH-SY5Y human neuroblastoma cells induced to differentiate with the phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TPA). A decrease in muscarinic receptor sensitivity with respect to agonist induced Ca2+ mobilization and receptor number parallelled the increase in membrane-associated protein kinase C (PK-C) activity. These changes occurred during the first 6 h of culture, and they were associated with rounding-up of cells. A subsequent decrease in particulate PK-C activity was followed by an increase in noradrenaline content, the appearance of an electrically excitable membrane, and an increase in the level of neuron-specific enolase. These changes were accompanied by a pronounced neurite outgrowth. 1-(5-lsoquinolinesulphonyl)-2-methylpiperazine (H-7), an inhibitor of PK-C and cyclic nucleotide-dependent protein kinases, enhanced the morphological differentiation induced by TPA, whereas N-(2-guanidinoethyl)-5-isoquinolinesulphonamide (HA-1004), which primarily inhibits cyclic nucleotide-dependent protein kinases, had no effect on the TPA-induced phenotypic differentiation. H-7 inhibited the decrease in muscarinic receptor sensitivity and receptor number, but had no effect on the appearance of the electrically excitable membrane or on the increase in the neuron-specific enolase level. Both H-7 and HA-1004 inhibited the TPA-induced increase in noradrenaline content.
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    URL: http://dx.doi.org/10.1002/jcp.1041400326
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    Differentiation-inducing and cytotoxic effects of tumor necrosis factor and interferon-gamma in myeloblastic ML-1 cells (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 141 (1989), S. 46-52 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The effects of the tumor necrosis factor (TNF), and a second pleiotropic cytokine interferon-gamma (IFN), were examined in a line of human myeloblastic leukemia cells (ML-1). By itself, TNF causes ML-1 to differentiate along the monocytic pathway. The cells exhibit an increase in Fc receptors and acquire the morphological characteristics of maturing phenotype. They remain viable and continue to proliferate (at ≥ 50% of the control growth rate) even with 102-104 units/ml TNF. IFN alone has similar effects, causing an increase in Fc receptors but little cytotoxicity. In contrast to either cytokine alone, the combination of TNF plus IFN causes a cessation of proliferation and extensive cell death. Cytotoxicity occurs in a synergistic fashion; it requires the simultaneous presence of both cytokines, occurring with concurrent but not sequential exposure. These different responses, differentiation (TNF alone) and cytotoxicity (TNF + IFN), occur with a similar range of doses (∼ 102-104 units/ml) and in a similar time frame (beginning on day 2). In other cell types, IFN can augment either the differentiation-inducing or the cytotoxic effect of TNF. In ML-1, the combined application of TNF plus IFN results in a shift from differentiation to cytotoxicity.
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    URL: http://dx.doi.org/10.1002/jcp.1041410108
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    ATP hydrolysis by ischemic Mitochondria (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 141 (1989), S. 53-59 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Cellular ATP levels are determined by the rates of ATP production and ATP hydrolysis. Both phenomena are affected by ischemia. Mitochondrial enzymes are damaged, inhibiting this organelle's ability to make ATP. Mitochondria are also uncoupled by ischemia and have the ability to hydrolyze ATP. We designed a series of experiments to determine whether decreased production or increased hydrolysis of ATP was the primary effect of mitochondrial damage. Rat hearts were subjected to 45 min of warm ischemia in order to induce irreversible cell damage. ATP or ADP was injected into cuvettes containing mitochondria isolated from normal myocardium or myocardium damaged by ischemia. Luciferin-luciferase, which fluoresces in the presence of ATP, was also added to the tubes as an indicator of ATP levels. Mixtures of uncoupled and coupled mitochondria were made and compared with the mitochondria damaged by ischemia. The results showed that mitochondria damaged by prolonged ischemia hydrolyze ATP more rapidly than normal mitochondria; however, normal mitochondria can easily compensate for increased ATP hydrolysis when in mixture with equal amounts of uncoupled mitochondria. These data suggests that the low cellular levels of ATP following irreversible ischemia are primarily due to decreased ATP synthesis and not to increased hydrolysis.
    Additional Material: 7 Ill.
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    URL: http://dx.doi.org/10.1002/jcp.1041410109
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    Functional receptors for nerve growth factor on Ewing's sarcoma and Wilm's tumor cells (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 141 (1989), S. 60-64 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Quantification of changes in levels of c-fos RNA was used as an indicator of the presence of functional responses to nerve growth factor in several human nonneuronal cell lines which have previously been shown to express high levels of NGF receptors. Four Ewing's sarcomas, one Wilm's tumor, and one melanoma were examined. Of these cell lines, the Ewing's sarcoma IARC-EW1 showed greatly increased levels (10-20-fold) of c-fos RNA after 1 hour of exposure to NGF. Except for the melanoma line, the other tumor lines exhibited small, but reproducible, elevation of c-fos RNA expression. In IARC-EW1 cells, this induction was analyzed for kinetics, dose-response, and suppression by selective inhibitors of NGF action. The results indicate that these cells bear high-affinity receptors for NGF, which utilize signal pathways similar to NGF receptors on PC12 cells. Thus, we report new types of cells with functional responses to NGF and indicate that these may constitute a new model which will usefully complement those presently used for studying the mechanism of action of NGF.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/jcp.1041410110
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    Tumor necrosis factor causes amplification of arachidonic acid metabolism in response to interleukin 1, bradykinin, and other agonists (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 141 (1989), S. 85-89 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Tumor necrosis factor stimulated prostaglandin E2 synthesis in Swiss 3T3 fibroblasts. Interleukin 1 also stimulated prostaglandin synthesis. Simultaneous addition of tumor necrosis factor and interleukin 1 synergistically stimulated prostaglandin synthesis, even when both growth factors were added at what would be supramaximal concentrations by themselves. Several small peptides and nonpeptides rapidly stimulate prostaglandin synthesis in these cells. Pretreatment with tumor necrosis factor synergistically enhanced prostaglandin synthesis in response to bradykinin, bombesin, thrombin, norepinephrine, and platelet-activating factor. Thus, tumor necrosis factor stimulates prostaglandin synthesis and greatly amplifies prostaglandin synthesis in response to other agonists. This finding may have significance in chronic inflammatory diseases such as rheumatoid arthritis in which several hormones and growth factors may synergistically augment eicosanoid synthesis.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/jcp.1041410113
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    Ultrastructure of spermiogenesis in the gastropod Calliotropis glyptus Watson (Prosobranchia: Trochidae)with special reference to the embedded acrosome (1989)
    New York, NY : Wiley-Blackwell
    Gamete Research 24 (1989), S. 9-19 
    Details
    ISSN: 0148-7280
    Keywords: Mollusca ; centrioles ; spermatid nucleus ; Trochoidea ; systemtics ; Archaeogastropoda ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Testicular spermatozoa and sperm development in the archaeogastropod Calliotropis glyptus Watson (Trochoidae: Trochidae) are examined using transmission electron microscopy and formalin-fixed tissues. During spermiogenesis, the acrosome, formed evidently through fusion of Golgi-derived proacrosomal vesicles, becomes deeply embedded in the condensing spermatid nucleus. Two centrioles (proximal and distal), both showing triplet microtubular substructure, are present in spermatids - the distal centriole giving rise to the sperm tail and its associated rootlet. During formation of the basal invagination in the spermatid nucleus, centrioles, and rootlet move towards the nucleus and come to lie totally within the basal invagination. Mitochondria are initially positioned near the base of the nucleus but subsequently become laterally displaced. Morphology of the mature spermatozoon is modified from that of the classic primitive or ect-aquasperm type by having 1) the acrosome embedded in the nucleus (the only known example within the Mollusca), 2) a deep basai invagination in the nucleus containing proximal and distal centrioles and an enveloping matrix (derived from the rootlet), 3) laterally displaced periaxonemal mitochondria, and 4) a tail extending from the basal invagination of the nucleus. Implantation of the acrosomal complex and centrioles within imaginations of the nucleus and lateral displacement of mitochondria effectively minimize the length of the sperm head and midpiece. Such modifications may be associated with motility demands, but this remains to be established. The unusual features of C. glyptus spermatozoa, though easily derivable from ‘typical’ trochoid sperm architecture, may prove useful in delineating the genus Calliotropis or tracing its relationship to other genera within the trochid subfamily Margaritinae.
    Additional Material: 20 Ill.
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    URL: http://dx.doi.org/10.1002/mrd.1120240104
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    Ultrastructural and histochemical changes in the murine zona pellucida during the final stages of oocyte maturation prior to ovulation (1989)
    New York, NY : Wiley-Blackwell
    Gamete Research 24 (1989), S. 35-48 
    Details
    ISSN: 0148-7280
    Keywords: ultrastructure ; zona pellucida ; preovulatory oocyte ; proteoglycans ; mouse ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The ultrastructural morphology of the mouse zona pellucida was studied in preovulatory follicles from the ovaries of immature mice treated with exogenous gonadotrophins. The ovaries were fixed in the presence of cetylpyridinium chloride, which precipitates carbohydrates, so that their loss during fixation and processing is substantially reduced. The semi-thin araldite sections obtained from osmicated material were viewed by conventional light microscopy, while the ultra-thin sections were examined by transmission electron microscopy. A parallel series of semi-thin sections of non-osmicated ovaries was deresined and subsequently stained with periodic acid Schiff (PAS). The morphological appearance of the zona pellucida in preovulatory oocytes changed during the final stages of oocyte maturation. A close correlation was observed between the ultrastructural appearance of the zona pellucida and that observed following PAS staining during the period studied. Real differences were observed in the location, density, and distribution of glycoconjugates within the zona pellucida during the final stages of oocyte maturation prior to and immediately following germinal vesicle breakdown. Similar changes in the zona were observed in adult females autopsied during proestrus and oestrus. The changes in the density and distribution of glycoconjugates are likely to have important consequences for fertilization by affecting sperm-zona binding and sperm-egg interactions.
    Additional Material: 21 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1120240107
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    Octaploid mouse embryos produced by electrofusion polarize and cavitate at the same time as normal embryos (1989)
    New York, NY : Wiley-Blackwell
    Gamete Research 24 (1989), S. 93-107 
    Details
    ISSN: 0148-7280
    Keywords: mouse embryo ; polarization ; octaploid ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: We created enlarged octaploid mouse blastomeres by subjecting four-cell embryos to a large (〉2.000 V/cm) dc field of brief duration (10 μsec). This electrofusion pulse caused three to four of the blastomcres to fuse in 60% of the embryos tested. Modifications of fusion chamber and medium enabled fusion of up to 20 embryos per pulse, greatly increasing the yield for this fusion method. The effectiveness of the electrofusion pulse depended upon such parameters as embryonic cell cycle time and the pH and temperature of the electrofusion medium. There was no discernable lag in the onset of the third cleavage division or the time of cavitation in fused blastomeres. These fused blastomeres also underwent polarization of their apical surfaces at the same time as controls in spite of their increased cell size. These results suggest that octaploid mouse blastomeres created via electrofusion divide normally through the blastocyst stage and polarize at the same time and in the same sequence as smaller control blastomeres. This suggests that the mechanisms underlying cell division, cavitation, and cortical polarization are not affected by changes in cellular size or ploidy.
    Additional Material: 7 Ill.
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    URL: http://dx.doi.org/10.1002/mrd.1120240112
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    Growth and development of rat oocytes in vitro (1989)
    New York, NY : Wiley-Blackwell
    Gamete Research 24 (1989), S. 109-121 
    Details
    ISSN: 0148-7280
    Keywords: oocyte ; meiosis ; preantral follicle ; growth ; rat ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Rat oocytes from preantral follicles have been shown to grow and acquire meiotic competence in vitro. Follicles were isolated by enzymatic digestion of ovaries from infant (10- or 11-day-old) Wistar rats. Follicles were cultured for up to 20 days in Minimum Essential Medium (MEM) supplemented with 2 mM hypoxanthine to maintain meiotic arrest. When cultures were begun, oocytes were in midgrowth phase (40-45 μm diameter), and were incapable of undergoing meiotic maturation when placed in hypoxanthine-free MEM. Oocytes grew and acquired meiotic competence during culture for 20 days attaining mean diameters of 62. 6 ± 0.6 μm and 61.1 ± 0.6 μm in two experiments. Germinal vesicle breakdown (GVB) occurred in 60-70% of oocytes when transferred to MEM without hypoxanthine. Concomitant with oocyte growth and maturation were spontaneous increases in follicular production of progestins, androgens and estrogens. When oocytes grown and matured in this system were inseminated in vitro with epididymal sperm, 36.1% and 25.8% were penetrated by one or more sperm in two experiments. However, fertilization was not generally normal with multiple penetrations and abnormal numbers of pronuclei (one or three) being common, suggesting that in these oocytes cytoplasmic maturation was incomplete or abnormal. In the two experiments, normal fertilization (two pronuclei and one sperm tail in the vitellus) occurred in 34.6% and 47 1% of penetrated oocytes with development of these apparently normal zygotes to two-cell embryos being 66.7% and 62.5%, respectively.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/mrd.1120240113
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    Reproductive endocrinology, 2nd Edition, by S. S. C. Yen and R. B. Jaffe; W. B. Saunders Company, Philadelphia, PA, 1985, 832 pp., $85 (1989)
    New York, NY : Wiley-Blackwell
    Gamete Research 24 (1989), S. 123-124 
    Details
    ISSN: 0148-7280
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1120240117
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    Reproduction in mammals, edited by C. R. Austin and R. V. Short; Cambridge university Press, London, 1982. Vol. 1: Germ Cells and Fertilization, 177 pp., $12.95, 1982; Vol. 2: Embryonic and Fetal Development, 190 pp., $12.95, 1982; Vol. 3: Hormonal Control of Reproduction, 244 pp., $16.95, 1984; Vol. 4: Reproductive Fitness, 241 pp., $14.95, 1985; Vol. 5: Manipulating Reproduction, 235 pp., $15.95, 1986 (1989)
    New York, NY : Wiley-Blackwell
    Gamete Research 24 (1989), S. 123-124 
    Details
    ISSN: 0148-7280
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1120240115
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    Masthead (1989)
    New York, NY : Wiley-Blackwell
    Gamete Research 24 (1989) 
    Details
    ISSN: 0148-7280
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1120240201
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    Progress in infertility, 3rd Edition, edited by S. J. Behrman, R. W. Kistner, and G. W. Patton; Little, Brown and Company, Boston, MA, 1987, 852 pp., $85 (1989)
    New York, NY : Wiley-Blackwell
    Gamete Research 24 (1989), S. 123-124 
    Details
    ISSN: 0148-7280
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1120240116
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  • 199
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    Effects of protein kinase C stimulation and free Ca2+ rise in mammalian egg activation (1989)
    New York, NY : Wiley-Blackwell
    Gamete Research 24 (1989), S. 171-183 
    Details
    ISSN: 0148-7280
    Keywords: PKC ; protein phosphorylation ; calcium, partenogenesis ; egg ; mammals ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Protein phosphorylation activity, chromosome segregation, and cortical granule exocytosis (CGE) have been studied in mouse eggs activated parthenogeneticaliy by specific PKC stimulators such as 4β-phorbol 12-myristate 13-acetate (PMA) and l-oleyl-2-acetylglycerol (OAG), or by agents inducing an immediate increase in cytosolic calcium concentration ([Ca2+]i) such as ethanol and Ca-ionophore A23187. When protein phosphorylation activity of mouse eggs was analyzed 10 min after different activation treatments, the phosphorylation of a 32 kDa polypeptide was a feature common to all different parthenogenetic agents used. The appearance of such labeling was independent of an increasing [Ca2+]i, as indicated by direct measurements of i) cytosolic Ca2+ concentration with fura-2 and 2) exogenous Ca2+ entrance into activated eggs. Emission of the second polar body was blocked in PMA-elicited partheno-genones, whereas it was apparently normal in OAG-treated eggs, unless the eggs were continuously exposed to OAG. CGE was almost immediate in ethanol-activated eggs, but in PMA-treated cells, it occurred significantly later, with a timing corresponding to that found for the appearance of sustained Ca2+ oscillations in this system. Here, we propose that in mammalian eggs 1) PKC stimulation represents an early regulatory step in egg activation; 2) this kinase activity is turned off before the second meiotic cleavage; and 3) cytosolic free Ca2+ rise is essential for CGE occurrence.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/mrd.1120240205
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    Parthenogenetic activation of unfertilized mouse oocytes by exposure to 1,2-propanediol is influenced by temperature, oocyte age, and cumulus removal (1989)
    New York, NY : Wiley-Blackwell
    Gamete Research 24 (1989), S. 269-279 
    Details
    ISSN: 0148-7280
    Keywords: propanediol ; dimethylsulfoxide ; ethanol ; hyaluronidase ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Cumulus-intact and -denuded unfertilized oocytes from two mouse strains were exposed to 1.5 m ethanol (EtOH) or two cryoproteclant solutions, 1.5 M propanediol (PROH) or 1.5 M dimethylsulfoxide (DMSO), for 4.5 min at 27°C, and the proportion of activating or degenerating oocytes studied. Exposure to DMSO did not significantly increase activation above that of oocytes not exposed to DMSO. Treatment of oocytes in PROH resulted in the activation of up to 87% of viable oocytes. This was significantly higher (P 〈01) than in control oocytes and comparable to the rate of activation after treatment with EtOH (59-96% activation). In solutions at 1°C, 47% of control oocytes were activated, which was not significantly different from the rate of activation in EtOH (36%) or PROH (50%) at 1°C. Following treatment with PROH, up to 87% of oocytes degenerated within a period of 6 h in vitro. The age of the oocytes (h post hCG) and the time of cumulus removal with the enzyme hyaluronidase, relative to the time of exposure to the chemicals, influenced the level of degeneration in most groups. Significantly fewer oocytes degenerated when cumulus cells were removed before treatment (0-31%) than when the cumulus was left intact throughout the treatment and 6 h culture period (10-87%). Exposure to PROH at 1°C reduced oocyte degeneration to 5%. We conclude that PROH causes significantly greater losses of oocytes as a result of parthenogenetic activation and degeneration than of exposure to DMSO.
    Additional Material: 5 Tab.
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    URL: http://dx.doi.org/10.1002/mrd.1120240304
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