The Experts below are selected from a list of 225 Experts worldwide ranked by ideXlab platform
Toshihiko Terao - One of the best experts on this subject based on the ideXlab platform.
-
Plasma P selectin (GMP-140) and Glycocalicin are elevated in preeclampsia and eclampsia: Their significances ☆ ☆☆ ★
American Journal of Obstetrics and Gynecology, 2005Co-Authors: Abdul Halim, Emad El Maradny, Akira Nakashima, A.b. Bhuiyanb, Selina Khatun, Naohiro Kanayama, Toshihiko TeraoAbstract:Abstract OBJECTIVE: We measured the concentrations of plasma P selectin (or GMP-140) and Glycocalicin in preeclamptic and eclamptic women. Correlations between these two parameters and blood pressures, platelet counts, or plasma thrombin-antithrombin complex values were evaluated. STUDY DESIGN: By use of enzyme-linked immunosorbent assays we measured the plasma GMP-140 and Glycocalicin levels in normal pregnancies ( n = 10) and preeclamptic ( n = 10) and eclamptic ( n = 20) pregnancies. The Glycocalicin index was calculated as follows: (Glycocalicin × [250 × 10 6 /ml])/(Individual platelet counts). Correlations between plasma GMP-140, Glycocalicin, Glycocalicin index values, blood pressures, platelet counts, and plasma thrombin-antithrombin complex values were analyzed. RESULTS: Plasma GMP-140 levels were found to be significantly elevated in preeclamptic ( p p p = 0.01, 0.007) and Glycocalicin index ( p = 0.005, 0.002) values were also markedly elevated in preeclamptic and eclamptic patients compared with normal pregnant patients. Significant correlations between platelet counts or plasma thrombin-antithrombin complex levels and their corresponding plasma GMP-140 and Glycocalicin and Glycocalicin index values have been found in preeclamptic and eclamptic cases. However, blood pressures had correlations with GMP-140, Glycocalicin, and Glycocalicin index values in eclamptic cases. CONCLUSIONS: We demonstrated an elevation of plasma GMP-140 and platelet Glycocalicin in preeclampsia and eclampsia. This study also reflects the usefulness of Glycocalicin as a marker of platelet activation or turnover and endothelial dysfunction in these diseases. (AM J OBSTET GYNECOL 1996;174:272-7.)
-
Plasma P selectin (GMP-140) and Glycocalicin are elevated in preeclampsia and eclampsia: their significances.
American journal of obstetrics and gynecology, 1996Co-Authors: Abdul Halim, Emad El Maradny, Akira Nakashima, Selina Khatun, A B Bhuiyan, Naohiro Kanayama, Toshihiko TeraoAbstract:We measured the concentrations of plasma P selectin (or GMP-140) and Glycocalicin in preeclamptic and eclamptic women. Correlations between these two parameters and blood pressures, platelet counts, or plasma thrombin-antithrombin complex values were evaluated. By use of enzyme-linked immunosorbent assays we measured the plasma GMP-140 and Glycocalicin levels in normal pregnancies (n = 10) and preeclamptic (n = 10) and eclamptic (n = 20) pregnancies. The Glycocalicin index was calculated as follows: (Glycocalicin x [250 x 10(6)/ml])/(Individual platelet counts). Correlations between plasma GMP-140, Glycocalicin, Glycocalicin index values, blood pressures, platelet counts, and plasma thrombin-antithrombin complex values were analyzed. Plasma GMP-140 levels were found to be significantly elevated in preeclamptic (p < 0.0005) and eclamptic cases (p < 0.0001) compared with normotensive controls. Plasma Glycocalicin (p = 0.01, 0.007) and Glycocalicin index (p = 0.005, 0.002) values were also markedly elevated in preeclamptic and eclamptic patients compared with normal pregnant patients. Significant correlations between platelet counts or plasma thrombin-antithrombin complex levels and their corresponding plasma GMP-140 and Glycocalicin and Glycocalicin index values have been found in preeclamptic and eclamptic cases. However, blood pressures had correlations with GMP-140, Glycocalicin, and Glycocalicin index values in eclamptic cases. We demonstrated an elevation of plasma GMP-140 and platelet Glycocalicin in preeclampsia and eclampsia. This study also reflects the usefulness of Glycocalicin as a marker of platelet activation or turnover and endothelial dysfunction in these diseases.
-
plasma p selectin gmp 140 and Glycocalicin are elevated in preeclampsia and eclampsia their significances
American Journal of Obstetrics and Gynecology, 1996Co-Authors: Abdul Halim, Emad El Maradny, Akira Nakashima, A.b. Bhuiyanb, Selina Khatun, Naohiro Kanayama, Toshihiko TeraoAbstract:Abstract OBJECTIVE: We measured the concentrations of plasma P selectin (or GMP-140) and Glycocalicin in preeclamptic and eclamptic women. Correlations between these two parameters and blood pressures, platelet counts, or plasma thrombin-antithrombin complex values were evaluated. STUDY DESIGN: By use of enzyme-linked immunosorbent assays we measured the plasma GMP-140 and Glycocalicin levels in normal pregnancies ( n = 10) and preeclamptic ( n = 10) and eclamptic ( n = 20) pregnancies. The Glycocalicin index was calculated as follows: (Glycocalicin × [250 × 10 6 /ml])/(Individual platelet counts). Correlations between plasma GMP-140, Glycocalicin, Glycocalicin index values, blood pressures, platelet counts, and plasma thrombin-antithrombin complex values were analyzed. RESULTS: Plasma GMP-140 levels were found to be significantly elevated in preeclamptic ( p p p = 0.01, 0.007) and Glycocalicin index ( p = 0.005, 0.002) values were also markedly elevated in preeclamptic and eclamptic patients compared with normal pregnant patients. Significant correlations between platelet counts or plasma thrombin-antithrombin complex levels and their corresponding plasma GMP-140 and Glycocalicin and Glycocalicin index values have been found in preeclamptic and eclamptic cases. However, blood pressures had correlations with GMP-140, Glycocalicin, and Glycocalicin index values in eclamptic cases. CONCLUSIONS: We demonstrated an elevation of plasma GMP-140 and platelet Glycocalicin in preeclampsia and eclampsia. This study also reflects the usefulness of Glycocalicin as a marker of platelet activation or turnover and endothelial dysfunction in these diseases. (AM J OBSTET GYNECOL 1996;174:272-7.)
Peter N Walsh - One of the best experts on this subject based on the ideXlab platform.
-
Factor XI Interacts with the Leucine-rich Repeats of Glycoprotein Ibα on the Activated Platelet
The Journal of biological chemistry, 2004Co-Authors: Frank A Baglia, Jose A Lopez, Zaverio M. Ruggeri, Corie N. Shrimpton, Jonas Emsley, Kouki Kitagawa, Peter N WalshAbstract:Abstract Factor XI (FXI) binds specifically and reversibly to high affinity sites on the surface of stimulated platelets (Kd app of ∼10 nm; Bmax of ∼1,500 sites/platelet) utilizing residues exposed on the Apple 3 domain in the presence of high molecular weight kininogen and Zn2+ or prothrombin and Ca2+. Because the FXI receptor in the platelet membrane is contained within the glycoprotein Ibα subunit of the glycoprotein Ib-IX-V complex (Baglia, F. A., Badellino, K. O., Li, C. Q., Lopez, J. A., and Walsh, P. N. (2002) J. Biol. Chem. 277, 1662–1668), we utilized mocarhagin, a cobra venom metalloproteinase, to generate a fragment (His1–Glu282) of glycoprotein Ibα that contains the leucine-rich repeats of the NH2-terminal globular domain and excludes the macroglycopeptide portion of Glycocalicin, the soluble extracytoplasmic portion of glycoprotein Ibα. This fragment was able to compete with FXI for binding to activated platelets (Ki of 3.125 ± 0.25 nm) with a potency similar to that of intact Glycocalicin (Ki of 3.72 ± 0.30 nm). However, a synthetic glycoprotein Ibα peptide, Asp269–Asp287, containing a thrombin binding site had no effect on the binding of FXI to activated platelets. Moreover, the binding of 125I-labeled thrombin to Glycocalicin was unaffected by the presence of FXI at concentrations up to 10-5 m. The von Willebrand factor A1 domain, which binds the leucine-rich repeats, inhibited the binding of FXI to activated platelets. Thus, we examined the effect of synthetic peptides of each of the seven leucine-rich repeats on the binding of 125I-FXI to activated platelets. All leucine-rich repeat (LRR) peptides derived from glycoprotein Ibα were able to inhibit FXI binding to activated platelets in the following order of decreasing potency: LRR7, LRR1, LRR4, LRR5, LRR6, LRR3, and LRR2. However, the leucine-rich repeat synthetic peptides derived from glycoprotein Ibβ and Toll protein had no effect. We conclude that FXI binds to glycoprotein Ibα at sites comprising the leucine-rich repeat sequences within the NH2-terminal globular domain that are separate and distinct from the thrombin-binding site.
-
Identification of a binding site for glycoprotein Ibα in the apple 3 domain of factor XI
The Journal of biological chemistry, 2004Co-Authors: Frank A Baglia, Jose A Lopez, David Gailani, Peter N WalshAbstract:Abstract Factor XI (FXI) is a homodimeric plasma zymogen that is cleaved at two internal Arg369–Ile370 bonds by thrombin, factor XIIa, or factor XIa. FXI circulates as a complex with the glycoprotein high molecular weight kininogen (HK). FXI binds to specific sites (Kd = ∼10 nm, Bmax = ∼1,500/platelet) on the surface of stimulated platelets, where it is efficiently activated by thrombin. The FXI Apple 3 (A3) domain mediates binding to platelets in the presence of HK and zinc ions (Zn2+) or prothrombin and calcium ions. The platelet glycoprotein (GP) Ib-IX-V complex is the receptor for FXI (Baglia, F. A., Badellino, K. O., Li, C. Q., Lopez, J. A., and Walsh, P. N. (2002) J. Biol. Chem. 277, 1662–1668). Using surface plasmon resonance, we determined that FXI binds specifically to Glycocalicin, the extracellular domain of GPIbα, in a Zn2+-dependent fashion (Kd = ∼52 nm). We now show that recombinant FXI A3 domain inhibits FXI inbinding to Glycocalicin in the presence of Zn2+, whereas the recombinant FXI A1, A2, or A4 domains have no effect. Experiments with full-length recombinant FXI mutants show that, in the presence of Zn2+, Glycocalicin binds FXI at a heparin-binding site in A3 (Lys252 and Lys253) and not by amino acids previously shown to be required for platelet binding (Ser248, Arg250, Lys255, Phe260, and Gln263). However, binding in the presence of HK and Zn2+ requires Ser248, Arg250, Lys255, Phe260, and GLn263 and not Lys252 and Lys253. Thus, binding of FXI to GPIbα is mediated by amino acids in the A3 domain in the presence or absence of HK. This interaction is important for the initiation of the consolidation phase of blood coagulation and the generation of thrombin at sites of platelet thrombus formation.
-
factor xi binding to the platelet glycoprotein ib ix v complex promotes factor xi activation by thrombin
Journal of Biological Chemistry, 2002Co-Authors: Frank A Baglia, Karen O Badellino, Jose A Lopez, Peter N WalshAbstract:Abstract Factor XI binds to high affinity sites on the surface of stimulated platelets where it is efficiently activated by thrombin. Here, we provide evidence that the factor XI binding site on platelets is in the glycoprotein (GP) Ibα subunit of the GP Ib-IX-V complex as follows. 1) Bernard-Soulier platelets, lacking the complex, are deficient in factor XI binding; 2) two GP Ibα ligands, SZ-2 (a monoclonal antibody) and bovine von Willebrand factor, inhibit factor XI binding to platelets; 3) by surface plasmon resonance, factor XI bound specifically to Glycocalicin (the extracellular domain of GP Ibα) in Zn2+-dependent fashion (K d app ∼ 52 nm). We then investigated whether Glycocalicin could promote factor XI activation by thrombin, another GP Ibα ligand. In the presence of high molecular weight kininogen (45 nm), Zn2+and Ca2+ ions, thrombin activated factor XI in the presence of Glycocalicin at rates comparable with those seen in the presence of dextran sulfate (1 μg/ml). With higher high molecular weight kininogen concentrations (360 nm), the rate of thrombin-catalyzed factor XI activation in the presence of Glycocalicin was comparable with that on activated platelets. Thus, factor XI binds to the GP Ib-IX-V complex, promoting its activation by thrombin.
Hans Deckmyn - One of the best experts on this subject based on the ideXlab platform.
-
Plasma Glycocalicin as a source of GPIbα in the von Willebrand factor ristocetin cofactor ELISA
Thrombosis and haemostasis, 2005Co-Authors: Karen Vanhoorelbeke, Inge Pareyn, Ágota Schlammadinger, S Vauterin, Marc Hoylaerts, Jef Arnout, Hans DeckmynAbstract:We have previously demonstrated that the von Willebrand factor ristocetin cofactor activity (VWF:RCo),used in the diagnosis of vonWillebrand disease (VWD),can be accurately determined via ELISA by measuring the ristocetin-induced binding ofVWF to a captured recombinant fragment of GPIbα (rfGPIbα ,AA 1n289) (Vanhoorelbeke et al., Thromb Haemost 2000; 83: 107-13). This ELISA is more reliable than the currently used platelet agglutination test. Normal plasma contains relatively high concentrations of Glycocalicin, a proteolytic fragment of GPIbα . We therefore studied whether non-purified plasma Glycocalicin can replace rfGPIbα in our ELISA. Of 42 anti-GPIbα monoclonal antibodies (MAbs) capable of binding plasma Glycocalicin, only one MAb captured Glycocalicin in a spatial orientation exposing theVWF-binding site in Glycocalicin,allowing a specific and dose-dependent ristocetin-mediated VWF-binding. Intra- and interassay variability were comparable with those for the rfGPIbα basedVWF:RCo ELISA.TheVWF:RCo activity of plasma from 33 normal individuals, 19 type 1, 16 type 2A, 9 type 2B, 8 type 2M and 7 type 3VWD patients was determined with this ELISA and allowed a clear identification ofVWD patients.Furthermore,determination of the VWF:RCo/VWF:Ag ratio resulted in the discrimination between type 1 and type 2 VWD patients. Results for the Glycocalicin based and the rfGPIb a basedVWF:RCo ELISAs were in good agreement (r = 0.943).There was also a good correlation between the Glycocalicin based ELISA and the standard platelet agglutination test (r = 0.963).In conclusion,to diagnose VWD, a VWF:RCo ELISA based on antibody immobilized plasma Glycocalicin can be performed reliably.
Jose A Lopez - One of the best experts on this subject based on the ideXlab platform.
-
Factor XI Interacts with the Leucine-rich Repeats of Glycoprotein Ibα on the Activated Platelet
The Journal of biological chemistry, 2004Co-Authors: Frank A Baglia, Jose A Lopez, Zaverio M. Ruggeri, Corie N. Shrimpton, Jonas Emsley, Kouki Kitagawa, Peter N WalshAbstract:Abstract Factor XI (FXI) binds specifically and reversibly to high affinity sites on the surface of stimulated platelets (Kd app of ∼10 nm; Bmax of ∼1,500 sites/platelet) utilizing residues exposed on the Apple 3 domain in the presence of high molecular weight kininogen and Zn2+ or prothrombin and Ca2+. Because the FXI receptor in the platelet membrane is contained within the glycoprotein Ibα subunit of the glycoprotein Ib-IX-V complex (Baglia, F. A., Badellino, K. O., Li, C. Q., Lopez, J. A., and Walsh, P. N. (2002) J. Biol. Chem. 277, 1662–1668), we utilized mocarhagin, a cobra venom metalloproteinase, to generate a fragment (His1–Glu282) of glycoprotein Ibα that contains the leucine-rich repeats of the NH2-terminal globular domain and excludes the macroglycopeptide portion of Glycocalicin, the soluble extracytoplasmic portion of glycoprotein Ibα. This fragment was able to compete with FXI for binding to activated platelets (Ki of 3.125 ± 0.25 nm) with a potency similar to that of intact Glycocalicin (Ki of 3.72 ± 0.30 nm). However, a synthetic glycoprotein Ibα peptide, Asp269–Asp287, containing a thrombin binding site had no effect on the binding of FXI to activated platelets. Moreover, the binding of 125I-labeled thrombin to Glycocalicin was unaffected by the presence of FXI at concentrations up to 10-5 m. The von Willebrand factor A1 domain, which binds the leucine-rich repeats, inhibited the binding of FXI to activated platelets. Thus, we examined the effect of synthetic peptides of each of the seven leucine-rich repeats on the binding of 125I-FXI to activated platelets. All leucine-rich repeat (LRR) peptides derived from glycoprotein Ibα were able to inhibit FXI binding to activated platelets in the following order of decreasing potency: LRR7, LRR1, LRR4, LRR5, LRR6, LRR3, and LRR2. However, the leucine-rich repeat synthetic peptides derived from glycoprotein Ibβ and Toll protein had no effect. We conclude that FXI binds to glycoprotein Ibα at sites comprising the leucine-rich repeat sequences within the NH2-terminal globular domain that are separate and distinct from the thrombin-binding site.
-
Identification of a binding site for glycoprotein Ibα in the apple 3 domain of factor XI
The Journal of biological chemistry, 2004Co-Authors: Frank A Baglia, Jose A Lopez, David Gailani, Peter N WalshAbstract:Abstract Factor XI (FXI) is a homodimeric plasma zymogen that is cleaved at two internal Arg369–Ile370 bonds by thrombin, factor XIIa, or factor XIa. FXI circulates as a complex with the glycoprotein high molecular weight kininogen (HK). FXI binds to specific sites (Kd = ∼10 nm, Bmax = ∼1,500/platelet) on the surface of stimulated platelets, where it is efficiently activated by thrombin. The FXI Apple 3 (A3) domain mediates binding to platelets in the presence of HK and zinc ions (Zn2+) or prothrombin and calcium ions. The platelet glycoprotein (GP) Ib-IX-V complex is the receptor for FXI (Baglia, F. A., Badellino, K. O., Li, C. Q., Lopez, J. A., and Walsh, P. N. (2002) J. Biol. Chem. 277, 1662–1668). Using surface plasmon resonance, we determined that FXI binds specifically to Glycocalicin, the extracellular domain of GPIbα, in a Zn2+-dependent fashion (Kd = ∼52 nm). We now show that recombinant FXI A3 domain inhibits FXI inbinding to Glycocalicin in the presence of Zn2+, whereas the recombinant FXI A1, A2, or A4 domains have no effect. Experiments with full-length recombinant FXI mutants show that, in the presence of Zn2+, Glycocalicin binds FXI at a heparin-binding site in A3 (Lys252 and Lys253) and not by amino acids previously shown to be required for platelet binding (Ser248, Arg250, Lys255, Phe260, and Gln263). However, binding in the presence of HK and Zn2+ requires Ser248, Arg250, Lys255, Phe260, and GLn263 and not Lys252 and Lys253. Thus, binding of FXI to GPIbα is mediated by amino acids in the A3 domain in the presence or absence of HK. This interaction is important for the initiation of the consolidation phase of blood coagulation and the generation of thrombin at sites of platelet thrombus formation.
-
Shear Stress-Induced Binding of Large and Unusually Large von Willebrand Factor to Human Platelet Glycoprotein Ibα
Annals of Biomedical Engineering, 2004Co-Authors: Joel L. Moake, Jose A Lopez, Larry V. McintireAbstract:Platelet membrane glycoprotein (GP) Ibα, a component of the GP Ib-IX-V complex, is a receptor for von Willebrand factor (VWF). A small quantity of large VWF multimers binds to platelets under high shear stress, and induces aggregation. We studied the shear-induced attachment of large and unusually large VWF multimers to the GPIbα extracellular domain (Glycocalicin), human platelets, and GPIbα gxpressing Chinese hamster ovary (CHO) cells. Compared to binding in the presence of botrocetin and ristocetin, shear stress only induced low-level NVWF (normal plasma VWF multimers) binding. This shear stress induced interaction is also dependent on VWF multimeric size. Elevated binding levels of endothelial cell VWF (enriched in unusually large VWF multimers) to Glycocalicin-coated beads were observed under low shear conditions, which did not result in the attachment of normal plasma VWF.
-
factor xi binding to the platelet glycoprotein ib ix v complex promotes factor xi activation by thrombin
Journal of Biological Chemistry, 2002Co-Authors: Frank A Baglia, Karen O Badellino, Jose A Lopez, Peter N WalshAbstract:Abstract Factor XI binds to high affinity sites on the surface of stimulated platelets where it is efficiently activated by thrombin. Here, we provide evidence that the factor XI binding site on platelets is in the glycoprotein (GP) Ibα subunit of the GP Ib-IX-V complex as follows. 1) Bernard-Soulier platelets, lacking the complex, are deficient in factor XI binding; 2) two GP Ibα ligands, SZ-2 (a monoclonal antibody) and bovine von Willebrand factor, inhibit factor XI binding to platelets; 3) by surface plasmon resonance, factor XI bound specifically to Glycocalicin (the extracellular domain of GP Ibα) in Zn2+-dependent fashion (K d app ∼ 52 nm). We then investigated whether Glycocalicin could promote factor XI activation by thrombin, another GP Ibα ligand. In the presence of high molecular weight kininogen (45 nm), Zn2+and Ca2+ ions, thrombin activated factor XI in the presence of Glycocalicin at rates comparable with those seen in the presence of dextran sulfate (1 μg/ml). With higher high molecular weight kininogen concentrations (360 nm), the rate of thrombin-catalyzed factor XI activation in the presence of Glycocalicin was comparable with that on activated platelets. Thus, factor XI binds to the GP Ib-IX-V complex, promoting its activation by thrombin.
Tomoki Naoe - One of the best experts on this subject based on the ideXlab platform.
-
Serum thrombopoietin and plasma Glycocalicin concentrations as useful diagnostic markers in thrombocytopenic disorders.
European journal of haematology, 2009Co-Authors: S. Kunishima, Sentaro Kobayashi, T. Tahara, Takashi Kato, Hiroshi Saito, Tomoki NaoeAbstract:Using enzyme-linked immunosorbent assays, we measured the concentrations of serum thrombopoietin (TPO) and plasma Glycocalicin, a proteolytic fragment of platelet glycoprotien Ib alpha, in 13 patients with myelodysplastic syndrome (MDS), aplastic anaemia (AA) or idiopathic thrombocytopenic purpura (ITP). In the patients with AA or MDS, the TPO concentrations were remarkably increased, and their Glycocalicin concentrations were decreased compared with the normal control individuals. In the patients with ITP, however, the TPO and Glycocalicin levels were not changed as much as in the AA/MDS patients in spite of the same degree of thrombocytopenia. During immunosuppressive treatment of ITP patients, there was an inverse relationship between the level of TPO and the platelet count. Thus, measurements of TPO and Glycocalicin levels are useful for the diagnosis of thrombocytopenia, and our results from ITP patients did not support the model which suggested the simple feedback regulation of TPO in thrombocytopenia.
-
increased but highly dispersed levels of plasma Glycocalicin in patients with disseminated intravascular coagulation
European Journal of Haematology, 2009Co-Authors: Shinji Kunishima, Sentaro Kobayashi, Tomoki NaoeAbstract:: Thrombocytopenia is one of the most common laboratory manifestations of disseminated intravascular coagulation (DIC). To investigate whether thrombocytopenia in DIC is indeed due to platelet consumption, we measured the plasma levels of Glycocalicin, a proteolytic fragment of the platelet membrane glycoprotein (GP) Ibα, a component of the GPIb/IX complex, in patients with solid tumors either with DIC (n = 18) or without DIC (n = 18). Patients with DIC had significantly elevated levels of Glycocalicin (2.53 ± 1.59 mg/l; n = 18, p<0.05) compared to those without DIC (1.50 ± 0.41 mg/l; n = 18), indicating enhanced platelet consumption, or destruction, in patients with DIC. However, Glycocalicin concentrations had a wide range (0.18–5.74 mg/l), and 3 DIC patients had levels lower than the normal lower limit. These findings suggest that, in patients with DIC, thrombocytopenia is not always due to increased platelet consumption, but it may be due to decreased production of platelets. Determination of plasma Glycocalicin concentrations is an easy way to identify thrombocytopenia, due to bone marrow insufficiency in these patients.
-
Increased but highly dispersed levels of plasma Glycocalicin in patients with disseminated intravascular coagulation.
European journal of haematology, 2009Co-Authors: Shinji Kunishima, Sentaro Kobayashi, Tomoki NaoeAbstract:: Thrombocytopenia is one of the most common laboratory manifestations of disseminated intravascular coagulation (DIC). To investigate whether thrombocytopenia in DIC is indeed due to platelet consumption, we measured the plasma levels of Glycocalicin, a proteolytic fragment of the platelet membrane glycoprotein (GP) Ibα, a component of the GPIb/IX complex, in patients with solid tumors either with DIC (n = 18) or without DIC (n = 18). Patients with DIC had significantly elevated levels of Glycocalicin (2.53 ± 1.59 mg/l; n = 18, p
-
Interaction of von Willebrand factor with the extracellular matrix and Glycocalicin under static conditions.
Journal of biochemistry, 1997Co-Authors: Taei Matsui, Tomoki Naoe, Yoshihiro Fujimura, Jiharu Hamako, Yasuhiro Ozeki, Masahiko Katayama, Shinji Kunishima, Tadashi Kamiya, Koiti TitaniAbstract:The binding of human von Willebrand factor (vWF) to a variety of extracellular matrix components immobilized on plates and the binding of vWF to platelet glycoprotein Ib (GPIb) after interacting with these matrix components were examined by means of an enzyme-linked immunosorbent assay. vWF preferably bound to type III collagen, whereas it did not significantly bind to type I, IV, V, or VI collagen, fibronectin, laminin, elastin, or proteoglycans. Soluble type III collagen did not bind to vWF coated on plates and showed a little effect on the vWF binding to the immobilized collagen, suggesting that solid-phase collagen is important for the interaction with vWF. When Glycocalicin, the N-terminal carbohydrate-rich extracellular domain of GPIb alpha exhibiting the vWF-binding activity, was added to vWF bound to collagen type III, no significant binding of Glycocalicin was observed, but it bound to vWF in the presence of botrocetin, a vWF modulator protein isolated from Bothrops jararaca snake venom. These results indicate that vWF immobilized on collagen can interact with GPIb but that binding of vWF to the collagen matrix alone is insufficient for modulating vWF so that it interacts with GPIb under static conditions. Another unknown physiological modulator functionally mimicking botrocetin or high-shear stress may be involved in the platelet adhesion to extracellular matrix in the early stage of hemostasis.
-
Rapid Detection of Plasma Glycocalicin by a Latex Agglutination Test: A Useful Adjunct in the Differential Diagnosis of Thrombocytopenia
American journal of clinical pathology, 1993Co-Authors: Shinji Kunishima, Tomoki Naoe, Sentaro Kobayashi, Akira Takagi, Ryuzo OhnoAbstract:To aid in the rapid differential diagnosis of thrombocytopenia, the authors developed a latex agglutination test for Glycocalicin, a proteolytic fragment of platelet membrane glycoprotein Ib. Plasma Glycocalicin determinations were performed for 34 patients with thrombocytopenia. Plasma samples from four patients with aplastic anemia and ten patients with myelodysplastic syndromes, all with Glycocalicin levels less than 0.6 mg/L by an enzyme-linked immunosorbent assay, all had negative results by the latex test. In contrast, positive latex agglutination titers were obtained for all 12 patients with idiopathic thrombocytopenic purpura. Eight patients with liver cirrhosis and splenomegaly had elevated levels of plasma Glycocalicin, and all of their plasma samples produced agglutination. This latex agglutination test for Glycocalicin allows a rapid discrimination of thrombocytopenia caused by impaired platelet production from that caused by increased platelet destruction; thus, it is suitable for use as a screening test in a routine clinical laboratory.