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  • 1995-1999  (6)
  • Cell & Developmental Biology  (4)
  • BLOOD COAGULATION  (2)
  • Analytical Chemistry and Spectroscopy
Material
Years
Year
Keywords
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Digestive diseases and sciences 44 (1999), S. 1349-1355 
    ISSN: 1573-2568
    Keywords: ANTITHROMBIN III ; THROMBIN ; HEPARIN ; BLOOD COAGULATION ; ACETALDEHYDE ; ALCOHOL ; ALCOHOLISM
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Acetaldehyde (AcH) at preincubationconcentrations of 447, 89.4, and 17.9 mM potentiates theeffects of heparin on the clotting time of plasma. Whilecontrol plasma clotted in the range of 12.6 ± 0.1 to 13.8 ± 0.1 sec, and heparin-treatedplasma clotted in a range from 131.5 ± 2.5 to168.2 ± 1.2 sec, heparin that was preincubated atroom temperature for 30 min with 89.4 or 447 mM AcH didnot clot plasma in 300 sec. Heparin exposed to 17.9 mMAcH clotted plasma in 193 ± 1.1 sec. Ethanol ata 404 mM concentration also prolonged the clotting timeof heparin-treated plasma 〉300 sec, while 202 mM ethanol prolonged the clotting time ofheparin-treated plasma from 149.0 ± 2.0 sec to219.5 ± 1.7 sec. It is suggested that AcH altersthe tertiary structure of heparin by adduct formation,possibly by formation of cyclic acetals with iduronicand glucuronic acids, thereby more readily affectingbinding of the glycosaminoglycan to antithrombin IIIand/or thrombin, prolonging clotting time. Ethanol, which does not react covalently with heparin,might affect its conformation as a consequence of anorganic solvent effect. Protamine sulfate prolonged theclotting time of plasma from 13.6 ± 0.1 sec to 17.9 ± 0.2 sec. Protaminesulfate-treated heparin clotted plasma in 21.0 ±0.4 sec relative to heparin-treated plasma (160.4± 1.7 sec). In subsequent experiments,AcH-treated protamine sulfate extended the clotting time of protamine sulfate from17.9 ± 0 sec to 33.7 ± 0.6 sec. Prioraddition of protamine sulfate to AcH- heparin mixturesor heparin to protamine sulfate-AcH mixtures beforeaddition to plasma resulted in clotting times of 22.0± 0.4 sec and 24.1 ± 0.5 sec,respectively, relative to control clotting times of162.3 ± 2.6 sec for plasma-heparin mixtures.These results confirm both the reduction in coagulation time ofheparin-treated plasma by protamine sulfate and theprolongation of clotting time of plasma by protaminesulfate. Furthermore, and importantly, they indicatethat acetaldehyde-treated protamine sulfate is a more effectiveanticoagulant than protamine sulfate. It is suggestedthat reversible adduct formation between acetaldehyde,heparin, and protamine sulfate may occur as a meansexplaining the essentially identical coagulation time ofthese mixtures when added to plasma regardless of theorder of premixing. Ethanol (404 mM) did not influenceprotamine sulfate effects. Lastly, the potentiation of the anticoagulant function of heparin byacetaldehyde suggests that a structural modification ofthe glycosaminoglycan may occur in alcoholics.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Digestive diseases and sciences 43 (1998), S. 1746-1751 
    ISSN: 1573-2568
    Keywords: ANTITHROMBIN III ; THROMBIN ; ACETALDEHYDE ; ALCOHOL ; ALCOHOLISM ; BLOOD COAGULATION
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The anticoagulant activity of antithrombin III(ATIII), as observed in a plasma-free system consistingof thrombin and fibrinogen, is readily reduced byacetaldehyde (AcH) at concentrations of 447, 89.4, and 17.9 mM. Whereas controlthrombin-fibrinogen mixtures clotted in 17.7 ±0.75 sec, ATIII prolonged clotting time to 55.0 ±1.75 sec on preincubation with thrombin for 30 min atroom temperature. On subsequent preincubation of ATIII with theAcH for 30 min at room temperature and passage of themixture through Sephadex G-25 minicolumns to removeexcess AcH, the eluates were tested for anticoagulant activity. Clotting times of 20.9 ± 1.0,32.3 ± 1.0, and 45.3 ± 1.6 sec wereobtained with 447, 89.4, and 17.9 mM AcH-ATIII mixtures,respectively. These data suggest that functional groupson ATIII, such as guanidiniums, aminos, and others aresusceptible to adduct formation with AcH, therebyaltering the shape and charge of the anticoagulant. Asa consequence of this type of reaction, an alteredmolecule of reduced biological activity may be produced.These experimental results may explain, in part, thereduction in ATIII levels reported by others in patientswith alcoholic liver disease.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 64 (1997), S. 390-402 
    ISSN: 0730-2312
    Keywords: carboxy-terminal repeat domain (CTD) ; RNA polymerase II ; cyclin-dependent kinases ; phosphorylation ; transcription ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Cdc2 kinase triggers the entry of mammalian cells into mitosis, the only cell cycle phase in which transcription is globally repressed. We show here that Cdc2 kinase phosphorylates components of the RNA polymerase II transcription machinery including the RNA polymerase II carboxy-terminal repeat domain (CTD). To test specifically the effect of CTD phosphorylation by Cdc2 kinase, we used a yeast in vitro transcription extract that is dependent on exogenous RNA polymerase II that contains a CTD. Phosphorylation was carried out using immobilized Cdc2 so that the kinase could be removed from the phosphorylated polymerase. ATPγS and Cdc2 kinase were used to produce an RNA polymerase 110 that was not detectably dephosphorylated in the transcription extract. RNA polymerase 110 produced in this way was defective in promoter-dependent transcription, suggesting that phosphorylation of the CTD by Cdc2 kinase can mediate transcription repression during mitosis. In addition, we show that phosphorylation of pol II with the human TFIIH-associated kinase Cdk7 also decreases transcription activity despite a different pattern of CTD phosphorylation by this kinase. These results extend previous findings that RNA polymerase 110 is defective in preinitiation complex formation. Here we demonstrate that phosphorylation of the CTD by cyclin-dependent kinases with different phosphoryl acceptor specificities can inhibit transcription in a CTD-dependent transcription system. J. Cell. Biochem. 64:390-402. © 1997 Wiley-Liss, Inc.
    Additional Material: 6 Ill.
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  • 4
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 165 (1995), S. 367-375 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The expression of the 72 kD inducible heat shock protein (hsp72) has been reported to be cell cycle associated in unheated, synchronized HeLa cells. In this study, flow cytomerty was used to investigate hsp72 levels through the cell cycle in HeLa cells by dual labeling with propidium iodide and antibodies against hsp72. The entire cell cycle distribution of hsp72 could be measured in a single sample of asynchronously growing cells. For unheated cells, the level of hsp72 increased about 30% from G1 to S phase, with about a 65% increase in G2/M, probably due to cell size differences. Neither mitotic selection nor serum stimulation induced a higher level of hsp72 than in the control cells. Western blot analysis of hsp72 from Hoechst-stained cells sorted from G1, mid-S, or G2/M showed that G1 cells had the lowest level of hsp72, with about a 30% increase in S phase and a 60% increase in G2/M, in good agreement with the flow cytometry results. These data conflict with previous reporty by other laboratories which showed a 3-fold higher level of hsp72 in S phase than in G1 or G2. In contrast, heat shock (both acute and chronic) led to a non-uniform increase in hsp72 through the cell cycle. Most cells in mid S phase had high levels of hsp72, and a larger range in the levels of hsp72 were found in G1 and late S/G2/M phase cells. © 1995 Wiley-Liss, Inc.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 164 (1995), S. 491-498 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: RNA blots of total cellular RNA isolated from quiescent and endothelin (ET-1)-stimulated normal rat kidney (NRK) cells demonstrated that ET-1 induced the expression of c-jun, jun B, and c-fos mRNA in a time-dependent manner with maximal expression of mRNA by 1 hr after the addition of ET-1. Five hundred picomolal ET-1 was sufficient to induce maximal mRNA expression. These data agreed with saturation experiments which demonstrated that maximal binding of [125I]ET-1 was achieved at concentrations greater than 100 pM. The Kd and Bmax values for [125I]ET-1 binding to NRK membranes were 20.5 pM and 22.2 fmol/mg protein, respectively. Competition experiments for the binding of [125I]ET-1 to NRK membranes demonstrated that ET-1 was a more potent inhibitor (Ki = 0.047 nM) than ET-3 (Ki = 10.8 nM). No specific binding of [125I]ET-3 (40 or 500 pM) to NRK membranes could be observed. The expression of c-jun, jun B, and c-fos mRNA was inhibited by the endothelin type A receptor (ET)-selective antagonist, BQ-123. Thus, these data demonstrate that ET-1 mediates the expression of immediate response gene mRNA in NRK cells via the ETA receptor. ET-1 stimulation of NRK cells also upregulated EGF receptors, providing a possible mechanism for ET-1 complementation of epidermal growth factor (EGF) mitogenicity in NRK cells. © 1995 Wiley-Liss, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    BioEssays 17 (1995), S. 129-138 
    ISSN: 0265-9247
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The plasma membrane of polarized epithelial cells is divided into apical and basolateral surfaces, with different compositions. Proteins can be sent directly from the trans-Golgi network (TGN) to either surface, or can be sent first to one surface and then transcytosed to the other. The glycosyl phosphatidylinositol anchor is a signal for apical targeting. Signals in the cytoplasmic domain containing a β-turn determine basolateral targeting and retrieval, and are related to other sorting signals. Transcytosed proteins, such as the polymeric immunoglobulin receptor (plgR), are endocytosed from the basolateral surface and then accumulate in a tubular compartment concentrated underneath the apical surface. This compartment, tentatively termed the apical recycling compartment, may be a central sorting station, as it apparently receives material from both surfaces and sorts them for delivery to the correct surface. Delivery to the apical surface from both the TGN and the apical recycling compartment appears to be regulated by protein kinases A and C, and endocytosis from the apical surface is also regulated by kinases. Transcytosis of the plgR is additionally regulated by phosphorylation of the plgR and by ligand binding to the plgR. Regulation of traffic in polarized epithelial cells plays a central role in cellular homeostasis, response to external signals and differentiation.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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