Blood Platelets ; Humans ; Platelet Membrane Glycoproteins ; Thrombosis

No abstract available.
Blood Platelets* ; Electrophoresis, Polyacrylamide Gel* ; Membrane Glycoproteins* ; Membranes* ; Thrombasthenia*

BACKGROUND: A previous history of transfusion has been known to be associated with production of anti-HLA class I antibodies. However, platelet glycoproteins are the main target of idiopathic thrombocytopenic purpura (ITP). The mechanism of antibody production is known to differ significantly between glycoproteins and anti-HLA class I. The aim of this study was to evaluate the clinical significance of anti-HLA class I antibodies in childhood ITP. METHODS: Enrollment for the normal control group targeted 48 people who visited Gyeongsang National University Hospital from 1990 to 2010, and 48 young children with ITP. Anti-glycoproteins and anti-HLA class I antibodies were tested using the Modified Antigen Capture Enzyme-linked immunosorbent assay (MACE) kit. RESULTS: The positive rate of anti-HLA antibodies was significantly different [36/39 (92.3%) vs 29/46 (63%)] [ITP group vs normal control group] (P=0.002). The mean positive S/C ratio of anti-HLA antibodies was also significantly different (3.55 vs 1.51) [ITP group vs normal control group] (P=0.0000). The positive rate of anti-HLA did not differ significantly between the transfused group and the non-transfused group [12/12 (100%) vs 24/27 (88%)] [transfused ITP vs non-transfused ITP]. The mean positive S/C ratio of anti-HLA antibodies did not differ significantly between the transfused ITP group and the non-transfused ITP group (4.30 vs 3.25) [transfused ITP vs non-transfused ITP]. Consecutive testing showed that positive rate and positive S/C ratio of anti-HLA antibodies did not change significantly between sampling times in both groups [transfused ITP vs non-transfused ITP] (P=1.00 and P=0.15). CONCLUSION: Anti-HLA class I antibodies may be involved in childhood ITP. Transfusion did not affect the course of childhood ITP.
Antibodies* ; Antibody Formation ; Blood Platelets* ; Child* ; Enzyme-Linked Immunosorbent Assay ; Glycoproteins ; Humans ; Platelet Membrane Glycoproteins ; Purpura, Thrombocytopenic, Idiopathic*

Glanzmann's thrombasthenia is a rare autosomal recessive hemorrhagic disorder characterized by prolonged bleeding time, ad deficient or absent clot retraction in the presence of normal platelet count. The major underlying abnormality in this disease is grossly defective first-phase aggregation of platelet, which are unresponsive to ADP or other platelet agonists such as epinephrine, collagen, thrombin in any concentration. This disability is caused by a decrease or absence of the platelet membrans glycoprotein IIb-IIIa complex, a member of the integrin family of adhesive receptors involved in cell-cell and cell-matrix fibronectin, and vitronectin On the development of surface labeling technique, a variety of biochemical techniques such as radioimmunoassay, crossed immunoelectrophoresis and SDS-PAGE have been used to study the structure and the function of platelet membrane glycoproteins, and to detect the platelet functional defect. But all of these techniques demand a relatively large amount of homogeneous paletelet population that requires manipulation through isolation and washing procedures before analysis. In order to eliminaste such an intricate procedure, we have applied method for analyzing platelet surface components in whole blood using monoclonal antibody and flow cytometry to recognize the absence of severe reduction of platelet membrane glycoprotien llb-llla complex. Platelet analysis by flow cytometry is a successful alternative rapid diagnostic technique for Glanzmann's thrombasthenia patients as well as well as for carriers of this disease. Fow cytometry technique provides a sensitive tool for investigating platelet functional defects caused by altered expression or deficiency of platelet surface proteins.
Adenosine Diphosphate ; Adhesives ; Bleeding Time ; Blood Platelets* ; Clot Retraction ; Collagen ; Electrophoresis, Polyacrylamide Gel ; Epinephrine ; Fibronectins ; Flow Cytometry* ; Glycoproteins ; Hemorrhagic Disorders ; Humans ; Immunoelectrophoresis, Two-Dimensional ; Membrane Glycoproteins* ; Membrane Proteins ; Membranes* ; Platelet Count ; Platelet Membrane Glycoproteins ; Radioimmunoassay ; Thrombasthenia* ; Thrombin ; Vitronectin

The binding of microorganisms to platelets is a critical step in the development of infective endocarditis. In Streptococcus gordonii, this binding is mediated in part by serine-rich repeat proteins, which interact directly with sialic acid residues located on GPIIb receptors in the platelet membrane. In this study, we found that S. gordonii DL1 strain binds to platelets through bridging between sialic acid residue of fibronectin and serine-rich repeat protein (Hsa). Pretreatment of fibronectin with sialidases specific for alpha(2-3)-linked sialic acids was shown to significantly inhibit binding of the DL1 strain and the binding region(BR) of Hsa protein. Similarly, pre-incubation of bacteria or BR of Hsa with alpha(2-3)-sialyl-N-acetyllactosamine blocked fibronectin binding in the DL1 strain, but not the M99 strain. Together, these data show that the alpha(2-3)-sialic acid residues of fibronectin play an important role in the binding of S. gordonii DL1 to fibronectin through interactions with the Hsa receptor. This interaction is thought to play an important role in the development of pathogenic endocarditis, and may represent an important therapeutic target for the treatment of infective endocarditis.
Bacteria ; Blood Platelets ; Endocarditis ; Etorphine ; Fibronectins* ; Membrane Glycoproteins* ; Membranes ; N-Acetylneuraminic Acid* ; Sialic Acids ; Streptococcus gordonii*

Immune thrombocytopenia (ITP) is an autoimmune hemorrhagic disease. It is considered that production of platelet auto-antibodies was one of the pathogenesis of ITP, first-line therapy including corticosteroid and immunoglobulin could reduce destruction of platelets by inhibiting production of auto-antibodies and blocking Fc-receptor of reticuloendothelial system, but some of the patients were refractory to first-line therapy and have persistent duration of the disease, having worse prognosis and developing into chronic/refractory ITP(C/RITP) . Platelet membrane glycoprotein like GPIIb/IIIa and GPIbα are the most common antigen targets, but first-line therapy was less effective to patients whose anti-GPIbα antibodies are positive. Further studies revealed that the way causing platelet destruction by anti-GPIIb/IIIa antibodies and anti-GPIbα antibodies are different: the former is mainly dependent to Fc-pathway, and the latter mainly cleared platelet by Fc-independent way. Results above indicated that detection of type of platelet auto-antibodies maybe potential to treatment and prognosis of ITP. This article summarizes relationship between platelet specific antibodies and the onset, clinical manifestation, treatment and prognosis of ITP.
Antibodies ; immunology ; Autoimmune Diseases ; Blood Platelets ; immunology ; Humans ; Platelet Membrane Glycoproteins ; Prognosis ; Thrombocytopenia ; immunology ; therapy

OBJECTIVETo investigate the protective effect of ulinastatin against the activation of tourniquet-induced platelet mitochondria apoptotic signaling.

METHOD44 patients with unilateral lower limb operation and tourniquet application were randomly divided into normal saline group and ulinastatin group, and were treated with normal saline and ulinastatin respectively. 12 patents with unilateral lower limb operation but without tourniquet application were enrolled in control group. Lipid hydroperoxide (LPO) in serum was detected by LPO assay kit, the content of ATP was examined by fluorescein-luciferase assay kit; the change of mitochondrial membrane potential (Δ ψm) was detected by JC-1 mitochondrial membrane potential kit; the content of cytoplasmic cytochrome C was examined by Cytochrome C ELISA kit; Caspase-3 activity was detected by Caspase-3 fluorometric assay kit.

RESULTSAs compared with control group, the patients in normal saline group exhibited significant platelet mitochondrial dysfunction which characterized by low ATP level and low mitochondrial membrane potential (Δ ψm) (P < 0.05). Tourniquet application resulted in the activation of the mitochondria apoptotic signaling in platelet, displaying increase in the serum LPO level, release of mitochondrial cytochrome C into the cytoplasm, and activation of caspase-3 (P < 0.05). These alterations above-mentioned were obviously improved by ulinastatin treatment (P < 0.05).

CONCLUSIONTourniquet induces platelet mitochondrial dysfunction and mitochondria-dependent apoptotic signaling activation, which can be improved by ulinastatin treatment.

Apoptosis ; Blood Platelets ; Caspase 3 ; Cytochromes c ; Glycoproteins ; Humans ; Membrane Potential, Mitochondrial ; Mitochondria ; Signal Transduction ; Tourniquets

No abstract available.
Blood Platelets* ; Electrophoresis, Polyacrylamide Gel* ; Flow Cytometry* ; Membrane Glycoproteins* ; Membranes* ; Thrombasthenia*

Glanzmann's thrombasthenia (GT) is a rare inherited platelet disorder, which is characterized by a complete lack of platelet aggregation due to a deficiency or abnormality of the membrane glycoprotein IIb/IIIa complex. Anti-GPIIb/IIIa antibodies have also been identified to cause platelet dysfunction in patients with a normal platelet count, but this has only been rarely encountered. The condition is also known as acquired GT. Herein, we describe a patient with acquired GT and a history of Evans' syndrome, who presented with severe bleeding and platelet dysfunction, but with a normal platelet count and GP IIb/IIIa expression.
Antibodies ; Blood Platelets ; Hemorrhage ; Humans ; Membrane Glycoproteins ; Platelet Aggregation ; Platelet Count ; Thrombasthenia*

OBJECTIVE: To analysis the specific protein markers of essential thrombocythemia (ET) based on proteomics technology, to explore and verify the differential protein related to platelet activation. METHODS: Blood samples were obtained from ET patients and healthy people and a certain protein mass spectrometry was detected using label-free quantitative technology. The proteins relative abundance increased or down-regulated by 1.3 times in the disease group compared with the control group, and the protein abundance in the two groups t test P＜0.05 were defined as differential proteins. Bioinformatics analysis of the differential proteins was performed using GO and KEGG. The difference in the average protein abundance between the two groups was analyzed by t test and P＜0.05 was considered statistically significant. Differential proteins were selected for verification by parallel reaction monitoring (PRM) technology. RESULTS: A total of 140 differential proteins were found, of which 72 were up-regulated and 68 were down-regulated. KEGG enrichment showed that the differential protein expression was related to the platelet activation pathway. The differential proteins related to platelet activation were GPV, COL1A2, GP1bα, COL1A1 and GPVI. Among them, the expressions of GPV, GP1bα and GPVI were up-regulated, and the expressions of COL1A2 and COL1A1 were down-regulated. PRM verification of COL1A1, GP1bα, GPVI and GPV was consistent with LFP proteomics testing. CONCLUSION Differential proteins in ET patients are related to platelet activation pathway activation.Differential proteins such as GPV, GPVI, COL1A1 and GP1bα can be used as new targets related to ET platelet activation.
Blood Platelets/metabolism* ; Humans ; Platelet Activation ; Platelet Membrane Glycoproteins/metabolism* ; Technology ; Thrombocythemia, Essential