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  • 1
    Electronic Resource
    Electronic Resource
    Transport enhancement and reversal: Glucose and 3-O-methyl glucose (1977)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 91 (1977), S. 155-168 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: In chick embryo fibroblast cultures the 15- to 30-fold enhancement of D-glucose uptake observed when cells are starved of glucose for 24 hours is not duplicated for derivatives of glucose that compete effectively for uptake and have generally been considered to use the same carrier. 2-deoxy-D-glucose, D-mannose, D-galactose and D-glucosamine are derepressed progressively less sharply in that order with glucosamine uptake never more than doubled by starvation. D-glucose at a concentration of 5.5 mM in the 24-hour conditioning medium is a strong “repressor” resulting in low “transport” behavior for each of the five sugars cited. D-glucosamine is equally effective at the same concentration. A 10-fold reduction in the concentration of glucosamine (0.55 mM) allows for the escape from repression of mannose, glucose, and deoxyglucose uptake while the others remain repressed. Mannose uptake escapes as well when the glucose concentration in the “conditioning” medium is similarly reduced.Under certain conditions of starvation and cell density dramatic effects of supplemental stimulation by insulin can be achieved. Insulin withdrawal interrupts the supplemental stimulation process. Cycloheximide, actinomycin D and cordycepin block both non-insulin and insulin-induced derepression. Short exposure (15-30 minutes) of 24-hour starved cells to glucose (5.5 mM) reduces glucose sharply but does not affect 3-O-methyl glucose uptake. If the exposure is to 2-deoxyglucose (5.5 mM) further derepression of glucose uptake results.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcp.1040910202
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  • 2
    Electronic Resource
    Electronic Resource
    Characterization of protein kinase C activity in interferon gamma treated murine peritoneal macrophages (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 125 (1985), S. 485-491 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Macrophage activation for tumoricidal and microbicidal functions can be achieved in part by treatment with recombinant interferon gamma (IFNγ) in vitro. We have previously demonstrated that IFNγ treatment of murine peritoneal macrophages results in a two- to five-fold increase in the activity of Ca++, phospholipid dependent protein kinase C (Hamilton et al., J. Biol. Chem., 260: 1378, 1985). We now report that this effect was not dependent upon continuing protein synthesis since treatment with cycloheximide under conditions where normal protein synthesis was inhibited by greater than 95% had no effect upon the development of increased enzyme activity. Examination of Ca++ and phospholipid requirements revealed no differences between enzyme isolated from control or IFNγ-treated cells could not be distinguished in terms of the diacyglycerol (DG) or phorbol diester (PMA) concentration required for stimulation of activity. Kinetic analysis of the ATP (as substrate)concentration dependence revealed that both control and treated enzyme preparations (either basal or stimulated) had comparable Km values. Maximum velocity (Vmax) was increased both by IFNγ treatment and also by stimulation with DG or PMA. The major difference which could be discerned between protein kinase C derived from control versus IFNγ-treated macro-phages was the magnitude of the response to DG or PMA; IFNγ treatment increased the stimulation index (i.e., ratio of basal to stimulated activity) by a factor of two to four fold. These results suggest that IFNγ treatment leads to reversible modulation of existing protein kinase C resulting in increased catalytic efficiency when exposed to an appropriate stimulant.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcp.1041250318
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  • 3
    Electronic Resource
    Electronic Resource
    Homologous and heterologous desensitization of proto-oncogene cfos expression in murine peritoneal macrophages (1987)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 131 (1987), S. 36-42 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Treatment of murine peritoneal macrophages for 30 min with lipopolysaccharide (LPS) resulted in a transient increase in c-fos proto-oncogene mRNA levels (Introna et al., 1986). After 2 h from the initial treatment, c-fos mRNA could no longer be detected and its expression could not be restimulated either by LPS or by other signals including colony stimulating factor-1 (CSF-1) and phorbol myristate acetate (PMA), both of which are able to induce expression of the c-fos gene in unstimulated macrophages. When LPS was removed after an initial 30 min incubation, responsiveness to a second exposure to LPS began to reappear after 3 h and was completely restored by 20 h. The same pattern of desensitization of c-fos induction was observed when CSF-1 stimulated macrophages were subsequently exposed to LPS. The loss of sensitivity to PMA following pretreatment with LPS was selective for c-fos expression as LPS treated macrophages remained responsive to PMA with respect to the ability to stimulate secretion of H2O2. The mechanism of desensitization was localized, at least in part, at the level of transcription as demonstrated by analysis of c-fos transcripts in nuclei isolated from macrophages pretreated and restimulated with LPS.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcp.1041310107
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  • 4
    Electronic Resource
    Electronic Resource
    Human skeletal growth factor stimulates collagen synthesis and inhibits proliferation in a clonal osteoblast cell line (MC3T3-E1) (1986)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 128 (1986), S. 307-312 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Human skeletal growth factor (hSGF), an 11-kD polypeptide purified from human bone, has been proposed to be a local regulator of bone formation. To investigate the underlying cellular mechanisms in an in vitro model system, we examined the effects of hSGF on proliferation and collagen synthesis in cells of the clonal osteoblast cell line MC3T3-E1. This line was isolated from newborn mouse calvarial cells and retains many characteristics of mature osteoblasts (Sudo, H., et al., (1984) J. Cell Biol. 96:191). A 14-hr treatment with hSGF increased noncollagenous protein synthesis to 215% of unstimulated controls and increased collagen synthesis to 630% of controls as determined by [3H]proline incorporation and high-pressure liquid chromatographic separation of [3H]proline and [3H]hydroxyproline in acid hydrolysates of trichloroacetic acid-insoluble protein. HSGF did not increase cell number over a 48-hr period and caused a reversible inhibition of DNA synthesis. Half-maximal hSGF concentration for stimulation of [3H]proline incorporation and inhibition of [3H]thymidine incorporation was 100 ng/ml. HSGF also inhibited DNA synthesis in cells stimulated by serum. In contrast, hSGF stimulated both collagen synthesis and DNA synthesis in primary cultures of chick embryo bone cells, which may be developmentally less mature than MC3T3-E1 cells. The results suggest that hSGF directly stimulated mature osteoblast matrix synthetic activity and that hSGF has differential effects on proliferation of osteoblast progenitor cells and mature osteoblasts.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcp.1041280224
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  • 5
    Electronic Resource
    Electronic Resource
    Effects of bacterial lipopolysaccharide on protein synthesis in murine peritoneal macrophages: Relationship to activation for macrophage tumoricidal function (1986)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 128 (1986), S. 9-17 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Early biochemical events in the response of murine peritoneal macrophages to bacterial lipopolysaccharide (LPS) have been examined (i.e., 0-4 hr after initiation of treatment). At concentrations of 10 ng/ml or less, LPS stimulated the new or enhanced synthesis of a series of at least six polypeptides of 85, 80, 75, 65, 57, and 38 kD. This effect was dependent upon the lipid A moiety of LPS as lipid A itself could induce the changes and the effect of LPS could be blocked by inclusion of polymixin B sulfate in the culture medium. The effect was specific for LPS in that other endotoxin-free agents known to alter macrophage physiology could not produce the same changes. The time course of LPS stimulation of macrophage protein synthesis was remarkable in that the synthesis of all six proteins was transient even in the continued presence of LPS, being first detected approximately 1 hr after exposure and no longer apparent by 8-10 hr after treatment was initiated. Furthermore, both pulse-chase and cumulative radiolabeling studies indicated that at least two of the proteins (85 and 38 kD) were short-lived and did not accumulate in LPS-treated cells, suggesting the possibility that they participate in a regulatory rather than a functional role. Macrophage tumoricidal activation involves cooperation in response to two independent signals; interferon gamma and LPS. Pretreatment of macrophages with interferon gamma increased the sensitivity of macrophages to LPS-stimulated protein synthesis by one to two orders of magnitude documenting such cooperativity in molecular terms. The LPS-induced stimulation of specific protein synthesis could be reproduced by treatment of macrophages with heat killed Listeria monocytogenes, a gram-positive, endotoxin-negative bacterial stain which has been shown to substitute effectively for LPS in macrophage tumoricidal activation. Furthermore, reversible inhibition (i.e., treatment with cycloheximide) of protein synthesis during LPS treatment abrogated the acquisition of tumoricidal function. These results identify an early biochemical response to LPS which may be a necessary component of the intracellular transduction of signals which regulate macrophage functional development.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcp.1041280103
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  • 6
    Electronic Resource
    Electronic Resource
    Comparison of the biological actions of TGF beta-1 and TGF beta-2: Differential activity in endothelial cells (1988)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 137 (1988), S. 167-172 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Beta transforming growth factor (TGF beta) has multiple in vitro biological effects including stimulation or inhibition of proliferation of specific cell types. A second major form of TGF beta, TGF beta-2, has recently been isolated from porcine platelets, from bovine bone matrix, and from several other sources. The two forms of TGF beta are biologically equipotent with the exception that TGF beta-2 was much less active than TGF beta-1 for inhibition of proliferation of a rat pleuripotent hematopoietic stem cell line. During the purification of beta TGF from bone, we obtained two fraction pools that differed in their ability to inhibit 3H-thymidine incorporation into aortic endothelial cells (AEC). We therefore compared highly purified TGF beta-1 and TGF beta-2 isolated from porcine platelets for inhibition of DNA synthesis in mink lung epithelial cells (MvlLu), and in AEC, and for stimulation of 3H-thymidine incorporation in calvarial bone cells (CBC) in 3 experiments. TGF beta-1 and TGF beta-2 inhibited cell proliferation in MvlLu with no significant differences in the ED50 (31± 8pg/ml vs 23± 7). TGF beta-2 was much less potent than TGF beta-1 in inhibiting DNA synthesis in AEC (6310 ± 985 pg/ml vs 101 ± 34). The reduced specific activity of TGF beta-2 was also observed in adrenal capillary endothelial cells. Both beta-1 and beta-2 stimulated proliferation of CBC (ED50 26 ± 2 pg/ml vs 10 ± 4). We also examined the specificity of the MvlLu and AEC inhibition assays. Epidermal growth factor (EGF), platelet derived growth factor (PDGF), acidic and basic fibroblast growth factor (FGF), skeletal growth factor (SGF)/insulin-like growth factor-II (IGF-II), and insulin-like growth factor-I (IGF-I) did not inhibit DNA synthesis in either assay system. However, when the growth factors were added to maximal inhibiting concentrations of TGF beta-1, both acidic and basic FGF significantly reduced TGF beta-1 inhibition in AEC. We conclude that (1) inhibition of DNA synthesis in endothelial cells is relatively specific for TGF beta-1, (2) inhibition of DNA synthesis in MvlLu is a sensitive and specific assay for generic TGF beta activity but does not distinguish beta-1 from beta-2, (3) the relative inhibition of DNA synthesis in MvlLu and AEC may provide a means to quantitatively estimate TGF beta-1 and TGF beta-2, and (4) both TGF beta-1 ad TGF beta-2 are potent mitogens for chicken embryonic calvarial bone cells.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcp.1041370120
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  • 7
    Electronic Resource
    Electronic Resource
    Observations on the development of the human atrioventricular node and bundleSupported by N.I.H. Grant HL07047. (1978)
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 192 (1978), S. 337-350 
    Details
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: This light microscopic study of the cardiac junctional tissues was based on 27 human embryos, fetuses and postnatal hearts. Evidence was presented that superficial and deep portions of the postnatal AV node were derived from two cellular primordia in the posterior wall of the common atrium at the 6-mm stage. The small right primordia was associated with the right venous valve and gave rise to the loosely organized superficial AV node that extended posteriorly to the coronary sinus ostium. A larger left primordia formed the more compact deep subdivision of the AV node located against the anulus fibrosus. In most postnatal hearts the two subdivisions are partially or completely fused to form the adult AV node. Failure of the nodal primordia to fuse during cardiogenesis may result in two separate nodal cell aggregates above the anulus. The present observations provide a rational explanation for the two AV nodal masses described in the literature and an additional specimen that is illustrated in this communication.An AV bundle was first identified in a 13-mm embryo and appeared to be derived from large clear cells of the posterior AV canal. At 25 mm the bundle formed a broad band across the top of the IV septum and continued into both ventricles. At this stage multiple cell strands penetrated the endocardial cushion to connect the AV bundle to the two nodal primordia. Failure of normal fusion between the AV node primordia and AV bundle can result in a variety of junctional anomalies including congenital heart block.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ar.1091920302
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  • 8
    Electronic Resource
    Electronic Resource
    Reversibility of the structural effects of pressure overload hypertrophy of cat right ventricular myocardium (1986)
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 214 (1986), S. 141-147 
    Details
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The purpose of the present quantitative structural study was to determine whether the histological alterations seen in pressure overloaded myocardium return to normal, as in vitro contractile function does, upon removal of the pressure overload stimulus. Three experimental groups of four cats each were studied: a group with pulmonary artery banding to create a pressure overload, a group that had been subjected to an equivalent duration of pressure overload and then had that pressure overload removed, and a group of sham-operated controls. Seven to 10 weeks after each operative procedure, the right ventricular pressure was elevated only in the pulmonary artery-banded group. The right ventricle/body weight ratio was significantly increased in the pressure overloaded group only. The body weight at sacrifice, the left ventricle/body weight ratio, and the right ventricular end-diastolic pressure did not differ significantly in the three groups. The striking histological changes in the right ventricular myocardium hypertrophying in response to a pressure overload were the decrease in the volume density of cardiocytes and the increase in connective tissue in papillary muscles. These were reversed when the pressure overload was removed. This study demonstrates that when a pressure overload is removed, myocardial structure returns to normal as the function returns to normal. Given the critical importance of the proportion of cardiocytes and connective tissue components to both systolic and diastolic cardiac function, these data support the hypothesis that the abnormal proportions of these structures provide a potential morphological basis for at least some of the functional abnormalities observed in pressure overload hypertrophy of the cat right ventricle.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ar.1092140206
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  • 9
    Electronic Resource
    Electronic Resource
    The development of the atrioventricular node and bundle in the ferret heartThis work is supported by N.I.H. Grant HL07047. (1979)
    New York, NY [u.a.] : Wiley-Blackwell
    American Journal of Anatomy 154 (1979), S. 135-150 
    Details
    ISSN: 0002-9106
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The development of the atrioventricular (AV) node and bundle in the ferret heart was examined at the light microscopic level. The AV node develops from two primordia which were first observed in the posterior wall of the common atrium during the stage when the single heart tube convolutes. During septation of the heart, the AV nodal primordia eventually fuse and come to lie at the base of the interatrial septum. The right AV nodal primordium is located below the attachment of the right venous valve to the interatrial septum. The left AV nodal primordium maintains a position anterior to the prospective ostium of the coronary sinus. At 16 days of gestation, large pale cells were seen in the dorsal AV canal. By 21 days of gestation these AV canal cells have been replaced by AV bundle cells. At this time the bundle is continuous with both nodal primordia. At birth the AV bundle is continuous mainly with the component of the AV node that is derived from the right AV node primordium. The anulus fibrosus begins to undergo the greatest developmental change after the AV node and bundle attain their final position in the AV junction. However, the anulus does not completely separate the atria from the ventricles during the later stages of development nor at birth, so that accessory AV pathways are present in the newborn ferret heart. Both the AV node and the AV bundle also demonstrated continuity with the myocardial cells of the interventricular septum in the neonatal heart. During development there was no evidence that rings of specialized tissues at the junctions of the cardiac chambers give rise to any component of the cardiac conduction system.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aja.1001540202
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  • 10
    Electronic Resource
    Electronic Resource
    The atrioventricular node and bundle in the ferret heart: A light and quantitative electron microscopic studyThis work was supported in part by N.I.H. grants HL07047, HL19425, HL19606, CA08231. (1979)
    New York, NY [u.a.] : Wiley-Blackwell
    American Journal of Anatomy 154 (1979), S. 365-391 
    Details
    ISSN: 0002-9106
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The cells of the atrioventricular (AV) junction in the ferret heart were examined using light microscopy, a wax-model reconstruction and quantitative electron microscopy to determine their organization and characteristics. A series of subdivisions of the specialized tissues of the AV junction was apparent at both the light and electron microscopic levels. A transitional zone was observed interposed between the atrial muscle cells and the AV node. The AV node consisted of a coronary sinus portion, a superficial portion and a deep portion. The AV bundle had a segment above the anulus fibrosus, a segment which penetrated the right fibrous trigone, a non-branching segment below the anulus fibrosus and a branched segment. At the ultrastructural level the AV junctional conduction tissues had fewer irregularly oriented myofibrils than did working atrial myocardial cells. T-tubules, present in atrial muscle cells, were not observed in the modified muscle cells of the AV node and bundle. Conventional intercalated discs also were not observed between the cells of the AV node or the AV bundle.Atrial myocardial cells had the highest percentage of the plasma membrane occupied by desmosomes, fasciae adherentes and gap junctions. The AV bundle cells had the highest percentage of appositional surface membrane and a relatively large fraction of plasma membrane occupied by gap junctions. Cells of the superficial portion of the AV node had the smallest percentage of the plasma membrane composed of gap junctions, desmosomes or fasciae adherentes, as well as the smallest fraction of the cell membrane apposed to adjacent cells. The stereological data indicate that the most useful distinguishing characteristic between atrial muscle cells and conduction cells was that a smaller percentage of the conduction cell sarcoplasm was occupied by mitochondria and myofibrils. The most useful characteristics that could be used to differentiate between the regions of the AV junctional conduction tissues were the amounts and types of surface membrane specializations in the respective cell types.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aja.1001540305
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