Добірка наукової літератури з теми "P-selectin ligand protein"
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Статті в журналах з теми "P-selectin ligand protein"
1
Lenter, M., A. Levinovitz, S. Isenmann, and D. Vestweber. "Monospecific and common glycoprotein ligands for E- and P-selectin on myeloid cells." Journal of Cell Biology 125, no. 2 (April 15, 1994): 471–81. http://dx.doi.org/10.1083/jcb.125.2.471.
Повний текст джерелаАнотація:
E- and P-selectin are inducible cell adhesion molecules on endothelial cells, which function as Ca(2+)-dependent lectins and mediate the binding of neutrophils and monocytes. We have recently identified a 150-kD glycoprotein ligand for E-selectin on mouse myeloid cells, using a recombinant antibody-like form of mouse E-selectin. Here, we report that this ligand does not bind to an analogous P-selectin fusion protein. Instead, the chimeric P-selectin-IgG protein recognizes a 160-kD glycoprotein on the mouse neutrophil progenitor 32D cl 3, on mature mouse neutrophils and on human HL60 cells. The binding is Ca(2+)-dependent and requires the presence of sialic acid on the ligand. This P-selectin-ligand is not recognized by E-selectin. Removal of N-linked carbohydrate side chains from the 150-kD and the 160-kD monospecific selectin ligands abolishes the binding of both ligands to the respective selectin. Treatment of HL60 cells with Peptide: N-glycosidase F inhibited cell binding to P- and E-selectin. In addition, glycoproteins of 230 and 130 kD were found on mature mouse neutrophils, which bound both to E- and P-selectin in a Ca(2+)-dependent fashion. The signals detected for these ligands were 15-20-fold weaker than those for the monospecific ligands. Both proteins were heavily sialylated and selectin-binding was blocked by removal of sialic acid, but not by removal of N-linked carbohydrates. Our data reveal that E- and P-selectin recognize two categories of glycoprotein ligands: one type requires N-linked carbohydrates for binding and is monospecific for each of the two selectins and the other type binds independent of N-linked carbohydrates and is common for both endothelial selectins.
2
Frenette, Paul S., Cécile V. Denis, Linnea Weiss, Kerstin Jurk, Sangeetha Subbarao, Beate Kehrel, John H. Hartwig, Dietmar Vestweber, and Denisa D. Wagner. "P-Selectin Glycoprotein Ligand 1 (Psgl-1) Is Expressed on Platelets and Can Mediate Platelet–Endothelial Interactions in Vivo." Journal of Experimental Medicine 191, no. 8 (April 17, 2000): 1413–22. http://dx.doi.org/10.1084/jem.191.8.1413.
Повний текст джерелаАнотація:
The platelet plays a pivotal role in maintaining vascular integrity. In a manner similar to leukocytes, platelets interact with selectins expressed on activated endothelium. P-selectin glycoprotein ligand 1 (PSGL-1) is the main P-selectin ligand expressed on leukocytes. Searching for platelet ligand(s), we used a P-selectin–immunoglobulin G (IgG) chimera to affinity purify surface-biotinylated proteins from platelet lysates. P-selectin–bound ligands were eluted with ethylenediaminetetraacetic acid. An ∼210-kD biotinylated protein was isolated from both human neutrophil and platelet preparations. A band of the same size was also immunopurified from human platelets using a monoclonal anti–human PSGL-1 antibody and could be blotted with P-selectin–IgG. Under reducing conditions, both the predicted PSGL-1 ∼210-kD dimer and the ∼120-kD monomer were isolated from platelets. Comparative immunoelectron microscopy and Western blotting experiments suggested that platelet PSGL-1 expression is 25–100-fold lower than that of leukocytes. However, patients with chronic idiopathic thrombocytopenic purpura who harbor predominantly young platelets displayed greater expression, indicating that PSGL-1 expression may be decreased during platelet aging. By flow cytometry, thrombin-activated platelets from normal individuals exhibited greater expression than those unstimulated. An inhibitory anti–PSGL-1 antibody significantly reduced platelet rolling in mesenteric venules, as observed by intravital microscopy. Our results indicate that functional PSGL-1 is expressed on platelets, and suggest an additional mechanism by which selectins and their ligands participate in inflammatory and/or hemostatic responses.
3
HARMS, Gesche, Regine KRAFT, Gerlinde GRELLE, Bärbel VOLZ, Jens DERNEDDE, and Rudolf TAUBER. "Identification of nucleolin as a new L-selectin ligand." Biochemical Journal 360, no. 3 (December 10, 2001): 531–38. http://dx.doi.org/10.1042/bj3600531.
Повний текст джерелаАнотація:
Apart from leucocyte–endothelial interactions, the adhesion molecule L-selectin mediates the homotypic adhesion of leucocytes during recruitment at sites of acute inflammation, as well as intercellular adhesion of haematopoietic progenitor cells during haematopoiesis. There is evidence that, in addition to P-selectin glycoprotein ligand-1, other as-yet-unidentified proteins function as L-selectin ligands on human leucocytes and haematopoietic progenitor cells. In the present study, we show: (i) by affinity chromatography on L-selectin–agarose; (ii) by protein identification using MS; and (iii) by covalent cell-surface labelling with sulphosuccinimidyl-2-(biotinamido)ethyl-1,3-dithiopropionate that the multifunctional nuclear protein nucleolin is partly exposed on the cell surface, and is a ligand of L-selectin in human leucocytes and haematopoietic progenitor cells.
4
Thomas, Susan N., Ronald L. Schnaar, and Konstantinos Konstantopoulos. "Podocalyxin-like protein is an E-/L-selectin ligand on colon carcinoma cells: comparative biochemical properties of selectin ligands in host and tumor cells." American Journal of Physiology-Cell Physiology 296, no. 3 (March 2009): C505—C513. http://dx.doi.org/10.1152/ajpcell.00472.2008.
Повний текст джерелаАнотація:
Selectins facilitate metastasis and tumor cell arrest in the microvasculature by mediating binding of selectin-expressing host cells to ligands on tumor cells. We recently identified CD44 variant isoforms as functional P-, but not E-/L-, selectin ligands on colon carcinoma cells. Furthermore, a ∼180-kDa sialofucosylated glycoprotein(s) mediated selectin binding in CD44-knockdown cells. Using immunoaffinity chromatography and tandem mass spectrometry, we identify podocalyxin-like protein (PCLP) as an alternative selectin ligand. Blot rolling and cell-free flow-based adhesion assays disclose that PCLP on LS174T colon carcinoma cells possesses E-/L-, but not P-, selectin binding activity. The selectin-binding determinants on LS174T PCLP are non-MECA-79-reactive sialofucosylated structures displayed on O-linked glycans, distinct from the MECA-79-reactive O-glycans on PCLP expressed by high endothelial venules, which is an L-selectin ligand. PCLP on CD44-knockdown LS174T cells exhibits higher HECA-452 immunoreactivity than PCLP on wild-type cells, suggesting that PCLP functions as an alternative acceptor for selectin-binding glycans. The enhanced expression of HECA-452 reactivity on PCLP from CD44-knockdown cells correlates with the increased avidity of PCLP for E- but not L-selectin. The novel finding that PCLP is an E-/L-selectin ligand on carcinoma cells offers a unifying perspective on the apparent enhanced metastatic potential associated with tumor cell PCLP overexpression and the role of selectins in metastasis.
5
Guyer, DA, KL Moore, EB Lynam, CM Schammel, S. Rogelj, RP McEver, and LA Sklar. "P-selectin glycoprotein ligand-1 (PSGL-1) is a ligand for L-selectin in neutrophil aggregation." Blood 88, no. 7 (October 1, 1996): 2415–21. http://dx.doi.org/10.1182/blood.v88.7.2415.bloodjournal8872415.
Повний текст джерелаАнотація:
In inflammation, activated neutrophils adhere to endothelial cells and aggregate with one another. While beta 2-integrin and L-selectin are essential for aggregation, their ligands remain to be identified. We have previously shown that L-selectin mediates a carbohydrate-dependent interaction in aggregation (Simon et al: J Immunol 149:2765, 1992; Rochon et al: J Immunol 152:1385, 1994). We have suggested that the L-selectin counter-structure is a mucinlike protein and proposed that aggregation occurs through a two-step process involving L-selectin, beta 2-integrin, and their distinct counter-structures (Bennett et al: J Leuk Biol 58:510, 1995). A candidate ligand for L-selectin is P-selectin glycoprotein ligand-1 (PSGL-1), a mucinlike protein on neutrophils that binds P-and E-selectin. Using flow cytometry we show that the number and size of neutrophil aggregates is reduced with Fab fragments of PL1, an anti-PSGL-1 monoclonal antibody that blocks the interaction between P-selectin and PSGL-1 (Moore et al: J Cell Biol 128:661, 1995). In addition, monoclonal antibodies to L-selectin and PSGL-1 were used simultaneously to modulate the availability of these adhesion molecules on individual cell populations. The inhibition of aggregation by these antibodies is consistent with L-selectin and PSGL-1 being counter-structures. We suggest that L-selectin and PSGL-1 support a collisional cell-cell interaction that represents the first step in neutrophil aggregation.
6
Moore, K. L., N. L. Stults, S. Diaz, D. F. Smith, R. D. Cummings, A. Varki, and R. P. McEver. "Identification of a specific glycoprotein ligand for P-selectin (CD62) on myeloid cells." Journal of Cell Biology 118, no. 2 (July 15, 1992): 445–56. http://dx.doi.org/10.1083/jcb.118.2.445.
Повний текст джерелаАнотація:
P-selectin (CD62, GMP-140, PADGEM), a Ca(2+)-dependent lectin on activated platelets and endothelium, functions as a receptor for myeloid cells by interacting with sialylated, fucosylated lactosaminoglycans. P-selectin binds to a limited number of protease-sensitive sites on myeloid cells, but the protein(s) that carry the glycans recognized by P-selectin are unknown. Blotting of neutrophil or HL-60 cell membrane extracts with [125I]P-selectin and affinity chromatography of [3H]glucosamine-labeled HL-60 cell extracts were used to identify P-selectin ligands. A major ligand was identified with an approximately 250,000 M(r) under nonreducing conditions and approximately 120,000 under reducing conditions. Binding of P-selectin to the ligand was Ca2+ dependent and was blocked by mAbs to P-selectin. Brief sialidase digestion of the ligand increased its apparent molecular weight; however, prolonged digestion abolished binding of P-selectin. Peptide:N-glycosidase F treatment reduced the apparent molecular weight of the ligand by approximately 3,000 but did not affect P-selectin binding. Western blot and immunodepletion experiments indicated that the ligand was not lamp-1, lamp-2, or L-selectin, which carry sialyl Le(x), nor was it leukosialin, a heavily sialylated glycoprotein of similar molecular weight. The preferential interaction of the ligand with P-selectin suggests that it may play a role in adhesion of myeloid cells to activated platelets and endothelial cells.
7
Zöllner, Olaf, Martin C. Lenter, James E. Blanks, Eric Borges, Martin Steegmaier, Hans-Günther Zerwes, and Dietmar Vestweber. "L-Selectin from Human, but Not from Mouse Neutrophils Binds Directly to E-Selectin." Journal of Cell Biology 136, no. 3 (February 10, 1997): 707–16. http://dx.doi.org/10.1083/jcb.136.3.707.
Повний текст джерелаАнотація:
L-Selectin on neutrophils as well as inducible E- and P-selectin on endothelium are involved in the recruitment of neutrophils into inflamed tissue. Based on cell attachment assays, L-selectin was suggested to function as a carbohydrate presenting ligand for E- and P-selectin. However, previous affinity isolation experiments with an E-selectin–Ig fusion protein had failed to detect L-selectin among the isolated E-selectin ligands from mouse neutrophils. We show here that L-selectin from human neutrophils, in contrast to mouse neutrophils, can be affinity-isolated as a major ligand from total cell extracts using E-selectin–Ig as affinity probe. Binding of human L-selectin to E-selectin was direct, since purified L-selectin could be reprecipitated with E-selectin–Ig. Recognition of L-selectin was abolished by sialidase-treatment, required Ca2+, and was resistant to treatment with endoglycosidase F. Binding of L-selectin to a P-selectin–Ig fusion protein was not observed. In agreement with the biochemical data, the anti–Lselectin mAb DREG56 inhibited rolling of human neutrophils on immobilized E-selectin–Ig but not on P-selectin–Ig. No such inhibitory effect was seen with the anti–mouse L-selectin mAb MEL14 on mouse neutrophils. Rolling of E-selectin transfectants on purified and immobilized human L-selectin was inhibited by mAb DREG56. We conclude that L-selectin on human neutrophils is a major glycoprotein ligand among very few glycoproteins that can be isolated by an E-selectin affinity matrix. The clear difference between human and mouse L-selectin suggests that E-selectin–binding carbohydrate moieties are attached to different protein scaffolds in different species.
8
Moore, K. L., K. D. Patel, R. E. Bruehl, F. Li, D. A. Johnson, H. S. Lichenstein, R. D. Cummings, D. F. Bainton, and R. P. McEver. "P-selectin glycoprotein ligand-1 mediates rolling of human neutrophils on P-selectin." Journal of Cell Biology 128, no. 4 (February 15, 1995): 661–71. http://dx.doi.org/10.1083/jcb.128.4.661.
Повний текст джерелаАнотація:
Neutrophils roll on P-selectin expressed by activated platelets or endothelial cells under the shear stresses in the microcirculation. P-selectin glycoprotein ligand-1 (PSGL-1) is a high affinity ligand for P-selectin on myeloid cells. However, it has not been demonstrated that PSGL-1 contributes to the rolling of neutrophils on P-selectin. We developed two IgG mAbs, PL1 and PL2, that appear to recognize protein-dependent epitopes on human PSGL-1. The mAbs bound to PSGL-1 on all leukocytes as well as on heterologous cells transfected with PSGL-1 cDNA. PL1, but not PL2, blocked binding of 125-I-PSGL-1 to immobilized P-selectin, binding of fluid-phase P-selectin to myeloid and lymphoid leukocytes, adhesion of neutrophils to immobilized P-selectin under static conditions, and rolling of neutrophils on P-selectin-expressing CHO cells under a range of shear stresses. PSGL-1 was localized to microvilli on neutrophils, a topography that may facilitate its adhesive function. These data indicate that (a) PSGL-1 accounts for the high affinity binding sites for P-selectin on leukocytes, and (b) PSGL-1 must interact with P-selectin in order for neutrophils to roll on P-selectin at physiological shear stresses.
9
Spertini, O., A. S. Cordey, N. Monai, L. Giuffrè, and M. Schapira. "P-selectin glycoprotein ligand 1 is a ligand for L-selectin on neutrophils, monocytes, and CD34+ hematopoietic progenitor cells." Journal of Cell Biology 135, no. 2 (October 15, 1996): 523–31. http://dx.doi.org/10.1083/jcb.135.2.523.
Повний текст джерелаАнотація:
Selectins play a critical role in initiating leukocyte binding to vascular endothelium. In addition, in vitro experiments have shown that neutrophils use L-selectin to roll on adherent neutrophils, suggesting that they express a nonvascular L-selectin ligand. Using a L-selectin/IgM heavy chain (mu) chimeric protein as an immunocytological probe, we show here that L-selectin can bind to neutrophils, monocytes, CD34+ hematopoietic progenitors, and HL-60 and KG-1 myeloid cells. The interaction between L-selectin and leukocytes was protease sensitive and calcium dependent, and abolished by cell treatment with neuraminidase, chlorate, or O-sialoglycoprotein endopeptidase. These results revealed common features between leukocyte L-selectin ligand and the mucin-like P-selectin glycoprotein ligand 1 (PSGL-1), which mediates neutrophil rolling on P- and E-selectin. The possibility that PSGL-1 could be a ligand for L-selectin was further supported by the ability of P-selectin/mu chimera to inhibit L-selectin/mu binding to leukocytes and by the complete inhibition of both selectin interactions with myeloid cells treated with mocarhagin, a cobra venom metalloproteinase that cleaves the amino terminus of PSGL-1 at Tyr-51. Finally, the abrogation of L- and P-selectin binding to myeloid cells treated with a polyclonal antibody, raised against a peptide corresponding to the amino acid residues 42-56 of PSGL-1, indicated that L- and P-selectin interact with a domain located at the amino-terminal end of PSGL-1. The ability of the anti-PSGL-1 mAb PL-1 to inhibit L- and P-selectin binding to KG-1 cells further supported that possibility. Thus, apart from being involved in neutrophil rolling on P- and E-selectin, PSGL-1 also plays a critical role in mediating neutrophil attachment to adherent neutrophils. Interaction between L-selectin and PSGL-1 may be of major importance for increasing leukocyte recruitment at inflammatory sites.
10
Evangelista, Virgilio, Stefano Manarini, Rita Sideri, Serenella Rotondo, Nicola Martelli, Antonio Piccoli, Licia Totani, et al. "Platelet/Polymorphonuclear Leukocyte Interaction: P-Selectin Triggers Protein-Tyrosine Phosphorylation–Dependent CD11b/CD18 Adhesion: Role of PSGL-1 as a Signaling Molecule." Blood 93, no. 3 (February 1, 1999): 876–85. http://dx.doi.org/10.1182/blood.v93.3.876.
Повний текст джерелаАнотація:
Abstract Polymorphonuclear leukocyte (PMN) adhesion to activated platelets is important for the recruitment of PMN at sites of vascular damage and thrombus formation. We have recently shown that binding of activated platelets to PMN in mixed cell suspensions under shear involves P-selectin and the activated β2-integrin CD11b/CD18. Integrin activation required signaling mechanisms that were sensitive to tyrosine kinase inhibitors.1 Here we show that mixing activated, paraformaldehyde (PFA)-fixed platelets with PMNs under shear conditions leads to rapid and fully reversible tyrosine phosphorylation of a prominent protein of 110 kD (P∼110). Phosphorylation was both Ca2+ and Mg2+ dependent and was blocked by antibodies against P-selectin or CD11b/CD18, suggesting that both adhesion molecules need to engage with their respective ligands to trigger phosphorylation of P∼110. The inhibition of P∼110 phosphorylation by tyrosine kinase inhibitors correlates with the inhibition of platelet/PMN aggregation. Similar effects were observed when platelets were substituted by P-selectin–transfected Chinese hamster ovary (CHO-P) cells or when PMN were stimulated with P-selectin–IgG fusion protein. CHO-P/PMN mixed-cell aggregation and P-selectin–IgG–triggered PMN/PMN aggregation as well as P∼110 phosphorylation were all blocked by antibodies against P-selectin or CD18. In each case PMN adhesion was sensitive to the tyrosine kinase inhibitor genistein. The antibody PL-1 against P-selectin glycoprotein ligand-1 (PSGL-1) blocked platelet/PMN aggregation, indicating that PSGL-1 was the major tethering ligand for P-selectin in this experimental system. Moreover, engagement of PSGL-1 with a nonadhesion blocking antibody triggered β2-integrin–dependent genistein-sensitive aggregation as well as tyrosine phosphorylation in PMN. This study shows that binding of P-selectin to PSGL-1 triggers tyrosine kinase–dependent mechanisms that lead to CD11b/CD18 activation in PMN. The availability of the β2-integrin to engage with its ligands on the neighboring cells is necessary for the tyrosine phosphorylation of P∼110.
Дисертації з теми "P-selectin ligand protein"
1
Troese, Matthew. "APPROACHES TO IDENTIFY SURFACE PROTEINS OF ANAPLASMA PHAGOCYTOPHILUM DENSE-CORED ORGANISMS AS ADHESINS TO HUMAN P-SELECTIN GLYCOPROTEIN LIGAND-1." VCU Scholars Compass, 2010. http://scholarscompass.vcu.edu/etd/162.
Повний текст джерелаАнотація:
Anaplasma phagocytophilum is an obligatory intracellular bacterium that infects neutrophils to cause human granulocytic anaplasmosis. Sialyl Lewis x (sLex)-modified P-selectin glycoprotein ligand-1 (PSGL-1) is the confirmed receptor utilized by A. phagocytophilum to bind and invade human neutrophils and myeloid cell lines. As an obligate intracellular pathogen, the binding of A. phagocytophilum to a host cell receptor is a prerequisite step for entry and replication, and thus its survival. However, the bacterial adhesins mediating this process have yet to be identified. In this study, we sought to identify surface proteins of A. phagocytophilum as putative adhesins. A. phagocytophilum undergoes a biphasic developmental cycle, transitioning between a smaller electron dense-cored cell (DC), which has a dense nucleoid, and a larger, pleomorphic electron lucent reticulate cell (RC), which has a dispersed nucleoid. We determined that the respective roles of the A. phagocytophilum DCs and RCs are adherence/infection and vacuolar replication, respectively, which is a finding that is consistent with the life cycles of other obligate intravacuolar pathogens that undergo biphasic development. Most importantly, we demonstrated the A. phagocytophilum DC is responsible for recognizing human PSGL-1. To identify surface proteins as putative adhesins we tested a variety of approaches. Three different computer prediction programs were compared, resulting in identification of 16 to 130 potential membrane proteins. As a more direct means to identify A. phagocytophilum surface proteins as PSGL-1 adhesins, several affinity capture approaches were tested. We used commercially available recombinant human PSGL-1 (rhPSGL-1) to try and capture adhesins by crosslinking and affinity purification. We were unsuccessful, but nevertheless gained insight into the binding properties of A. phagocytophilum. We next chose to take a broader approach to identify outer membrane proteins of the adherent DC by biotinylation. In the process we developed new density-gradient centrifugation approaches which successfully purified an RC-enriched population as well as a mixed population of RC and DC organisms. Results from this work demonstrate that A. phagocytophilum DC organisms are responsible for binding PSGL-1. Additionally, the results obtained thus far of gradient-purified bacteria will serve as a foundation for future experiments in identifying surface and developmental form specific proteins.
2
Liu, Hsuan-Fu, and 劉軒甫. "Post-translational protein tyrosine sulfation of P-selectin glycoprotein ligand 1: tyrosylprotein sulfotransferase selection mechanism on the sulfation site." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/01170853773871948714.
Повний текст джерелаАнотація:
碩士國立交通大學
生物科技學系
105
Protein tyrosine sulfation (PTS) is a common post-translational modification frequently found in secreted and transmembrane proteins and a key modulator for extracellular protein-protein interactions. PTS mediates many physiological processes, including coagulation, leukocyte adhesion, virus infection, and chemokine signaling. One of the prominent examples is the sulfation of tyrosine residue on the N-terminal region of P-selectin glycoprotein ligand-1 (PSGL-1), which enforces its interaction with P-selectin and specific enterovirus. Using PSGL-1 as a model substrate, we investigate how tyrosylprotein sulfotransferase (TPST) recognizes one of the three potential tyrosine sulfation sites in the protein. On the contrary to what generally proposed in the literature, we determined that there are one major and one minor sulfation sites among the three tyrosines. In addition, we found that the second tyrosine is sulfated only after the first PTS near the C-terminal was completed. The selection of the tyrosine for sulfation is variously regulated by the two surrounding acidic amino acids, aspartic and glutamic acids. While surrounding acidic amino acids are critical for the tyrosine sulfation, two near-by glutamic acids prohibit one of the three PSGL-1 tyrosine for sulfation. In addition, mutation at the tyrosine sulfation site produced strong TPST inhibitors. We proposed that the location of tyrosine on the protein/peptide substrate was also an important factor to determine the priority of which tyrosine to get sulfated. Our proposed model and molecular modeling explained why mutant of PSGL-1 peptide become strong TPST inhibitors with the change of specific active site tyrosine.
Частини книг з теми "P-selectin ligand protein"
1
Conrad, Richard C., Sabine Bell, and Andrew D. Ellington. "In vitro selection of nucleic acid ligands." In RNA:Protein Interactions, 285–326. Oxford University PressOxford, 1998. http://dx.doi.org/10.1093/oso/9780199636518.003.0012.
Повний текст джерелаАнотація:
Abstract The molecular biology explosion of the last three decades has been capped by the finding that nucleic acids have extraordinary functionality. Once thought to be mere repositories or carriers of information, the discovery of structural complexity in tRNA and catalysis in group I self-splicing intrans and eubacte rial RNase P RNAs prompted the realization that nucleic acids may harbour biochemistries as complex as those of protein enzymes. The discovery that functional nucleic acids could be generated by natural selection led directly to the notion that researchers might themselves design or select nucleic acids with novel functions. For example, researchers have modified the functions of existing ribozymes, much as protein chemists engineered the physical and catalytic properties of known protein enzyme. In addition, researchers have selected binding or catalytic nucleic acid species de novo from pools of nucleic acid molecules that contained literally trillions of different sequences.
Тези доповідей конференцій з теми "P-selectin ligand protein"
1
Imai, Yohsuke, Hitoshi Kondo, Young Ho Kang, Takuji Ishikawa, Chwee Teck Lim, and Takami Yamaguchi. "A Numerical Model of Adhesion Property of Malaria Infected Red Blood Cells in Micro Scale Blood Flows." In ASME 2009 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2009. http://dx.doi.org/10.1115/sbc2009-206456.
Повний текст джерелаАнотація:
Infection by malaria parasite changes mechanical properties of red blood cells (RBCs). Infected red blood cells (IRBCs) lose the deformability but also develop the ability to cytoadhere and rosetting. These outcomes can lead to microvascular blockage [1]. The stiffness of IRBCs [2] and its effects on the flow in micro channels [3] were studied with recent experimental techniques. The cytoadherence and rosetting properties of IRBCs have also been studied experimentally. The cytoadherence is mediated by the interaction of the parasite protein PfEMP1 with several endothelial adhesion molecules, such as CD36, intercellular adhesion molecule-1 (ICAM-1), P-selectin, and vascular cell adhesion molecule-1 (VCAM-1) [4]. In particular, the ligand-receptor interaction between PfEMP1 and CD36 shows tight adhesion [5]. Microvascular blockage may be a hemodynamic problem, involving the interactions between IRBCs, healthy RBCs (HRBCs) and endothelial cells (ECs) in flowing blood, but however experimental techniques have several limitations to this topic. First, it is still difficult to observe the RBC behavior interacting with many other cells even with the recent confocal microscopy. Second, the three-dimensional information on flow field is hardly obtained. Third, capillaries in human body are circular channels with complex geometry, but such complex channels cannot be created in micro scale. Instead, numerical modeling can overcome these problems. We presented a two-dimensional hemodynamic model involving adhesive interactions [6]. In this paper, we propose a three-dimensional model of the adhesive interactions for micro scale hemodynamics in malaria infection.
2
Wachtfogel, Yanina T., Yizhar Floman, Meir Liebergall, Robert W. Colman, and Amiram Eldor. "PLATELET ALPHA2-ADRENERGIC RECEPTOR ABNORMALITIES IN PATIENTS WITH IDIOPATHK: SCOLIOSIS." In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1644567.
Повний текст джерелаАнотація:
Idiopathic scoliosis is a genetic multisystem disease involving skeletal, biochemical, central nervous svstem, muscle and blood platelet abnormalities. Platelets of patients with idiopathic scoliosis have been shown to have decreased adenosine diphosphate and epinephrine-induced aggregation. Similarities between the contractile protein system of platelets and muscle have made the platelet a popular model for certain aspects of muscle physiology. This study confirmed that 64% of the patient platelets tested exhibited a significantly decreased sensitivity to aggregation bv epinephrine. In seven of the eleven patients studied, epinephrine induced aggregation was markedly decreased, i.e., the threshold of agonist was markedly elevated ≥11 uM). The geometric mean concentration of epinephrine required to produce complete second-wave aggregation in idiopathic scoliosis patients was 8μM. as compared to a control concentration of luM. We therefore examined the platelet alpha2-adrenergic receptors of 17 patients with idiopathic scoliosis bv measuring ligand binding using the selective antagonist, methyl yohimbine. Platelets from healthv individuals had 185 ± 16 sites per platelet with a Kd of 1.90 ± 0.32 nM, while patients with idiopathic scoliosis had 54 ± 22 sites per platelet with a of 1.02 ± 0.03 nM. The number of binding sites per platelet in idiopathic scoliosis patients were significantly decreased (p < 0.05) as compared to controls , while the was not significantly different (p > 0.05) between the two groups. Seven of these patients exhibited a significant decrease (p < 0.05) in the number of alpha2-adrenergic receptors on their platelets while the binding in 7 additional patients was undetectable.Three patients exhibited normal receptor number and affinity as compared to normal individuals. This study indicates a profound alteration in the number and function of the alpha2-adrenergic receptors in platelets of patients with idiopathic scoliosis and indicates the functional heterogeneity of the receptor disorder. Further investigation of platelet abnormalities may give insight into the putative muscle defects.