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Platelets in hemostasis and thrombosis:Novel mechanisms of fibrinogen-independent platelet aggregation and fibronectin-mediated protein wave of hemostasis 被引量:24
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作者 Yan Hou Naadiya Carrim +3 位作者 Yiming Wang Reid C.Gallant Alexandra Marshall Heyu Ni 《The Journal of Biomedical Research》 CAS CSCD 2015年第6期437-444,共8页
Platelets are small anucleate cells generated from megakaryocytes in the bone marrow. Although platelet genera- tion, maturation, and clearance are still not fully understood, significant progress has been made in the... Platelets are small anucleate cells generated from megakaryocytes in the bone marrow. Although platelet genera- tion, maturation, and clearance are still not fully understood, significant progress has been made in the last 1-2 dec- ades. In blood circulation, platelets can quickly adhere and aggregate at sites of vascular injury, forming the platelet plug (i.e. the first wave of hemostasis). Activated platelets can also provide negatively charged phosphatidylserine- rich membrane surface that enhances cell-based thrombin generation, which facilitates blood coagulation (i.e. the second wave of hemostasis). Platelets therefore play central roles in hemostasis. However, the same process of hemostasis may also cause thrombosis and vessel occlusion, which are the most common mechanisms leading to heart attack and stroke following ruptured atherosclerotic lesions. In this review, we will introduce the classical mechanisms and newly discovered pathways of platelets in hemostasis and thrombosis, including fibrinogen-inde- pendent platelet aggregation and thrombosis, and the plasma fibronectin-mediated "protein wave" of hemostasis that precedes the classical first wave of hemostasis. Furthermore, we briefly discuss the roles of platelets in inflam- marion and atherosclerosis and the potential strategies to control atherothrombosis. 展开更多
关键词 platelets thrombosis and hemostasis integrin αIIbβ3 FIBRINOGEN FIBRONECTIN
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Human platelets inhibit liver fibrosis in severe combined immunodeficiency mice 被引量:17
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作者 Kazuhiro Takahashi Soichiro Murata +1 位作者 Kiyoshi Fukunaga Nobuhiro Ohkohchi 《World Journal of Gastroenterology》 SCIE CAS 2013年第32期5250-5260,共11页
AIM:To investigate the role of human platelets in liver fibrosis.METHODS:Severe combined immunodeficiency(SCID)mice were administered CCl4and either phosphate-buffered saline(PBS group)or human platelet transfusions(h... AIM:To investigate the role of human platelets in liver fibrosis.METHODS:Severe combined immunodeficiency(SCID)mice were administered CCl4and either phosphate-buffered saline(PBS group)or human platelet transfusions(hPLT group).Concentrations of hepatocyte growth factor(HGF),matrix metallopeptidases(MMP)-9,and transforming growth factor-β(TGF-β)in the liver tissue were compared between the PBS and the hPLT groups by enzyme-linked immunosorbent assay(ELISA)and Western blotting.The effects of a human platelet transfusion on liver fibrosis included the fibrotic area,hydroxyproline content,and-smooth muscle actin(α-SMA)expression,which were evaluated by picrosirius red staining,ELISA,and immunohistochemical staining using an anti-mouse-SMA antibody,respectively.Phosphorylations of mesenchymal-epithelial transition factor(Met)and SMAD3,downstream signals of HGF and TGF-β,were compared between the two groups by Western blotting and were quantified using densitometry.Hepatocyte apoptosis was evaluated by terminal deoxynucleotidyl transferase dUTP nick end labeling.Furthermore,the accumulation of human platelets in the liver 2 h after platelet transfusion was compared between normal and fibrotic livers by immunohistochemical staining using an anti-human CD41 antibody.RESULTS:The fibrotic area and hydroxyproline content in the liver were both significantly lower in the hPLT group when compared to the PBS group(fibrotic area,1.7%±0.6%vs 2.5%±0.6%,P=0.03;hydroxyproline content,121±26 ng/g liver vs 156±47 ng/g liver,P=0.04).There was less α-smooth muscle actin staining in the hPLT group than in the PBS group(0.5%±0.1%vs 0.8%±0.3%,P=0.02).Hepatic expression levels of mouse HGF and MMP-9were significantly higher in the hPLT group than in the PBS group(HGF,109±13 ng/g liver vs 88±22 ng/g liver,P=0.03;MMP-9,113%±7%/GAPDH vs 92%±11%/GAPDH,P=0.04).In contrast,the concentration of mouse TGF-β in the liver tissue was significantly lower in the hPLT group than in the PBS group(22±5ng/g liver vs 39±6 ng/g liver,P=0.02).Phosphorylation of Met was more prevalent in the hPLT group than in the PBS group(37%±4%/GAPDH vs 20%±8%/GAPDH,P=0.03).Phosphorylation of SMAD3was weaker in the hPLT group than in the PBS group(60%±12%/GAPDH vs 84%±12%/GAPDH,P=0.1),although this difference was not significant.Furthermore,a lower rate of hepatocyte apoptosis was observed in the hPLT group than in the PBS group(5.9%±1.7%vs 2.9%±2.1%,P=0.02).Significant human platelet accumulation was observed in the fibrotic liver tissues,whereas few platelets accumulated in the normal liver.CONCLUSION:Human platelets inhibit liver fibrosis in SCID mice.Increased concentration of HGF in the liver suppresses hepatic stellate cell activation,induces MMPs,and inhibits hepatocyte apoptosis. 展开更多
关键词 Human platelet Liver fibrosis HEPATOCYTE apoptosis HEPATOCYTE GROWTH FACTOR TRANSFORMING GROWTH factor-β Matrix metallopeptidases
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Multipotent role of platelets in inflammatory bowel diseases:A clinical approach 被引量:31
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作者 Evangelos Voudoukis Konstantinos Karmiris Ioannis E Koutroubakis 《World Journal of Gastroenterology》 SCIE CAS 2014年第12期3180-3190,共11页
There is evidence that inflammatory bowel diseases (IBD) combine both inflammation and coagulation in their pathogenesis and clinical manifestations. Although platelets (PLT) are well known for their role in hemostasi... There is evidence that inflammatory bowel diseases (IBD) combine both inflammation and coagulation in their pathogenesis and clinical manifestations. Although platelets (PLT) are well known for their role in hemostasis, there are a rising number of studies supporting their considerable role as inflammatory amplifiers in chronic inflammatory conditions. IBD are associated with several alterations of PLT, including number, shape, and function, and these abnormalities are mainly attributed to the highly activated state of circulating PLT in IBD patients. When PLT activate, they increase in size, release a great variety of bio-active inflammatory and procoagulant molecules/particles, and express a variety of inflammatory receptors. These inflammatory products may represent a part of the missing link between coagulation and inflammation, and can be considered as possible IBD pathogenesis instigators. In clinical practice, thrombocytosis is associated both with disease activity and iron deficiency anemia. Controlling inflammation and iron replacement in anemic patients usually leads to a normalization of PLT count. The aim of this review is to update the role of PLT in IBD and present recent data revealing the possible therapeutic implications of anti-PLT agents in future IBD remedies. 展开更多
关键词 Anemia Crohn’ s disease platelets Thrombocytosis Ulcerative colitis
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Influence of Kupffer cells and platelets on ischemia-reperfusion injury in mild steatotic liver 被引量:6
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作者 Koichi Ogawa Tadashi Kondo +4 位作者 Takafumi Tamura Hideki Matsumura Kiyoshi Fukunaga Tatsuya Oda Nobuhiro Ohkohchi 《World Journal of Gastroenterology》 SCIE CAS 2013年第9期1396-1404,共9页
AIM: To investigate the effect of mild steatotic liver on ischemia-reperfusion injury by focusing on Kupffer cells (KCs) and platelets. METHODS: Wistar rats were divided into a normal liver group (N group) and a mild ... AIM: To investigate the effect of mild steatotic liver on ischemia-reperfusion injury by focusing on Kupffer cells (KCs) and platelets. METHODS: Wistar rats were divided into a normal liver group (N group) and a mild steatotic liver group (S group) induced by feeding a choline-deficient diet for 2 wk. Both groups were subjected to 20 min of warm ischemia followed by 120 min of reperfusion. The number of labeled KCs and platelets in sinusoids and the blood perfusion in sinusoids were observed by intravital microscopy (IVM), which was performed at 30, 60 and 120 min after reperfusion. To evaluate serum alanine aminotransferase as a marker of liver deterioration, blood samples were taken at the same time as IVM.RESULTS: In the S group, the number of platelets adhering to KCs decreased significantly compared with the N group (120 after reperfusion; 2.9±1.1 cells/acinus vs 4.8±1.2 cells/acinus, P<0.01). The number of KCs in sinusoids was significantly less in the S group than in the N group throughout the observation periods (before ischemia, 19.6±3.3 cells/acinus vs 28.2±4.1 cells/acinus, P<0.01 and 120 min after reperfusion, 29.0±4.3 cells/acinus vs 40.2±3.3 cells/acinus, P<0.01). The blood perfusion of sinusoids 120 min after reperfusion was maintained in the S group more than in the N group. Furthermore, elevation of serum alanine aminotransferase was lower in the S group than in the N group 120 min after reperfusion (99.7±19.8 IU/L vs 166.3±61.1 IU/L, P=0.041), and histological impairment of hepatocyte structure was prevented in the S group. CONCLUSION: Ischemia-reperfusion injury in mild steatotic liver was attenuated compared with normal liver due to the decreased number of KCs and the reduction of the KC-platelet interaction. 展开更多
关键词 Steatotic LIVER MILD steatotic LIVER KUPFFER cell platelet ISCHEMIA-REPERFUSION Intravital microscopy
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Platelets and depression in cardiovascular disease:A brief review of the current literature 被引量:23
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作者 Marlene S Williams 《World Journal of Psychiatry》 SCIE 2012年第6期114-123,共10页
Major depression is an independent risk factor for cardiovascular mortality and morbidity. The exact mechanisms linking depression and increased cardiovascular risk remain poorly understood. Several mechanisms have be... Major depression is an independent risk factor for cardiovascular mortality and morbidity. The exact mechanisms linking depression and increased cardiovascular risk remain poorly understood. Several mechanisms have been proposed including increased platelet reactivity. This review focuses on the current literature that examines the platelet hypothesis of depression. To date studies show increased serotonin response, increased platelet serotonin receptor density, decreased serotonin transporter binding, and decreased platelet serotonin levels in individuals with depression. However other studies have shown no change in serotonin uptake. In addition to platelet serotonin specific pathways, other platelet pathways that have shown significant changes in depressed individuals include blunting of the platelet adenosine response, increased platelet thrombin response, increased glycoprotein Ⅰb expression, increased P-selectin, β thromboglobulin, and platelet factor four, as well as decreased platelet brain derived neurotrophic factor. However there are other studies that show conflicting evidence of increased platelet activation as measured by integrin receptor α2b β3. Other conflictingdata include α adrenergic density and platelet response to augmented serotonin. The direction of future research in platelet functional changes in depression and coronary artery disease should continue to focus on serotonin specific pathways with emphasis on potential mechanisms of specific pathway changes. 展开更多
关键词 platelets DEPRESSION Coronary artery disease SEROTONIN Polymorphism Selective SEROTONIN REUPTAKE inhibitor THROMBIN Brain derived NEUROTROPHIC factor
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Platelets in liver disease, cancer and regeneration 被引量:29
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作者 Tomohiro Kurokawa Nobuhiro Ohkohchi 《World Journal of Gastroenterology》 SCIE CAS 2017年第18期3228-3239,共12页
Although viral hepatitis treatments have evolved over the years, the resultant liver cirrhosis still does not completely heal. Platelets contain proteins required for hemostasis, as well as many growth factors require... Although viral hepatitis treatments have evolved over the years, the resultant liver cirrhosis still does not completely heal. Platelets contain proteins required for hemostasis, as well as many growth factors required for organ development, tissue regeneration and repair. Thrombocytopenia, which is frequently observed in patients with chronic liver disease(CLD) and cirrhosis, can manifest from decreased thrombopoietin production and accelerated platelet destruction caused by hypersplenism; however, the relationship between thrombocytopenia and hepatic pathogenesis, as well as the role of platelets in CLD, is poorly understood. In this paper, experimental evidence of platelets improving liver fibrosis and accelerating liver regeneration is summarized and addressed based on studies conducted in our laboratory and current progress reports from other investigators. In addition, we describe our current perspective based on the results of these studies. Platelets improve liver fibrosis by inactivating hepatic stellate cells, which decreases collagen production. The regenerative effect of platelets in the liver involves a direct effect on hepatocytes, a cooperative effect with liver sinusoidal endothelial cells, and a collaborative effect with Kupffer cells. Based on these observations, we ascertained the direct effect of platelet transfusion on improving several indicators of liver function in patients with CLD and liver cirrhosis. However, unlike the results of our previous clinical study, the smaller incremental changes in liver function in patients with CLD who received eltrombopag for 6 mo were due to patient selection from a heterogeneous population. We highlight the current knowledge concerning the role of platelets in CLD and cancer and anticipate a novel application of platelet-based clinical therapies to treat liver disease. 展开更多
关键词 platelet Liver cirrhosis Liver regeneration CANCER THROMBOPOIETIN Thrombopoietin agonist ELTROMBOPAG
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Platelets:A possible glance into brain biological processes in schizophrenia 被引量:3
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作者 Eyal Asor Dorit Ben-Shachar 《World Journal of Psychiatry》 SCIE 2012年第6期124-133,共10页
Schizophrenia is a severe mental disorder, characterized by behavioral, emotional and cognitive disturbances,which commonly follows a chronic course. Diagnostic accuracy, management plans, treatment evaluation and pro... Schizophrenia is a severe mental disorder, characterized by behavioral, emotional and cognitive disturbances,which commonly follows a chronic course. Diagnostic accuracy, management plans, treatment evaluation and prognosis are dependent on relatively subjective assessments. Despite extensive research and improvement in imaging technology, as well as modern genetic and molecular methodologies, the biological basis of this disease is still unclear. Therefore, there is a need for objective and valid biological markers. Platelets have often been used as a model in neurobiological research. The accessibility of platelets and their similarities with neurons turns them into an attractive candidate to search for biological markers for diagnosis and for unraveling pathophysiological processes relevant to the etiology of brain disorders, including schizophrenia.The present review addresses the main changes in platelet physiology observed in schizophrenia and its response to antipsychotic medication. We summarize numerous studies demonstrating impaired metabolism,uptake and receptor kinetics of schizophrenia-relevantneurotransmitters, abnormalities in membrane derived phospholipids and polyunsaturated fatty acids, as well as dysfunctions in the mitochondria. These changes fit with the various hypotheses raised for the etiology of schizophrenia, including the dopamine-glutamate hypothesis, the autoimmune hypothesis, the polyunsaturated fatty acid hypothesis and the impaired energy metabolism hypothesis. Despite extensive research in platelets, no conclusive reliable biomarker has been identified yet. This review suggests that the clinical heterogeneity and the biological complexity of schizophrenia lead to the inevitable conclusion that biomarkers will be identified only for subgroups characterized according to the different diagnostic criteria. Moreover, any biomarker would have to be an array of interrelated factors or even a set of several such arrays. 展开更多
关键词 platelets SCHIZOPHRENIA Biomarkers
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Tumor-infiltrating platelets predict postoperative recurrence and survival in resectable pancreatic neuroendocrine tumor 被引量:1
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作者 Shuai-Shuai Xu Hua-Xiang Xu +6 位作者 Wen-Quan Wang Shuo Li Hao Li Tian-Jiao Li Wu-Hu Zhang Liang Liu Xian-Jun Yu 《World Journal of Gastroenterology》 SCIE CAS 2019年第41期6248-6257,共10页
BACKGROUND Platelets have been reported to participate in tumor cell growth,extravasation,epithelial–mesenchymal transition,metastasis,and drug resistance.However,the importance of platelets in pancreatic neuroendocr... BACKGROUND Platelets have been reported to participate in tumor cell growth,extravasation,epithelial–mesenchymal transition,metastasis,and drug resistance.However,the importance of platelets in pancreatic neuroendocrine tumor(pNET)lacks adequate literature support.The predictive value of tumor-infiltrating platelets(TIPs)in pNET remains unclear.AIM To investigate the relationship between TIPs and the prognosis of patients with pNET following radical resection.METHODS In total,113 patients who had undergone radical surgical resection with a pathologic diagnosis of pNET were enrolled in this study.Immunohistochemical analysis of cluster of differentiation 42b(CD42b)expression in the tumor specimens was performed to determine the presence of TIPs.Univariate and multivariate analyses were used to analyze the prognostic value of TIPs.RESULTS TIPs were observed in intratumoral areas in 54 patients.Neither basic characteristics nor preoperative platelet-associated indicators showed a significant relationship with the presence of TIPs(all P>0.05).Patients with positive intratumoral CD42b expression had worse overall survival(P=0.005)and recurrence-free survival(P<0.001)than those with negative intratumoral CD42b expression.Multivariate analysis demonstrated that TIPs were independent prognostic factors for overall survival(P=0.049)and recurrencefree survival(P=0.003).Nevertheless,platelet count,mean platelet volume,and platelet-to-lymphocyte ratio were not associated with postoperative survival or recurrence in pNET patients(all P>0.05).CONCLUSION TIPs are a useful prognostic biomarker for patients with resectable pNET,and their detection represents a promising tool for pNET treatment strategy decisions. 展开更多
关键词 Tumor-infiltrating platelets Pancreatic NEUROENDOCRINE TUMOR SURVIVAL Recurrence platelet count Mean platelet volume platelet-to-lymphocyte ratio
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Interaction between circulating cancer cells and platelets:clinical implication 被引量:3
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作者 Xiao-Liang Lou Jian Sun +3 位作者 Shu-Qi Gong Xue-Feng Yu Rui Gong Huan Deng 《Chinese Journal of Cancer Research》 SCIE CAS CSCD 2015年第5期450-460,共11页
Metastasis is the main cause of cancer-associated mortality. During this complicated process, some cancer cells, also called circulating tumor cells (CTCs), detach from primary sites, enter bloodstream and extravasa... Metastasis is the main cause of cancer-associated mortality. During this complicated process, some cancer cells, also called circulating tumor cells (CTCs), detach from primary sites, enter bloodstream and extravasate at metastatic site. Thrombocytosis is frequently observed in patients with metastatic cancers suggesting the important role of platelets in metastasis. Therefore this review focuses on how platelets facilitate the generation of CTCs, protect them from various host attacks, such as immune assaults, apoptosis and shear stress, and regulate CTCs intravasation/extravasation. Platelet-derived cytokines and receptors are involved in this cascade. Identification the mechanisms underlie platelet-CTCs interactions could lead to the development of new platelet-targeted therapeutic strategy to reduce metastasis. 展开更多
关键词 Circulating tumor cells (CTCs) platelet epithelial-mesenchymal transition (EMT) immunesurveillance METASTASIS
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Preparation of sol-gel derived microcrystalline corundum abrasives with hexagonal platelets 被引量:2
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作者 Na Li Yu-Mei Zhu +1 位作者 Kai Gao Zhi-Hong Li 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2013年第1期71-75,共5页
The effects of different additives on the mechanical properties, microstructures, and wear behavior of corundum abra- sives were investigated. When the number of additive phases increases, the sintering temperature an... The effects of different additives on the mechanical properties, microstructures, and wear behavior of corundum abra- sives were investigated. When the number of additive phases increases, the sintering temperature and wear rate decrease, while the densification and mechanical properties increase. The additive SiO2 is responsible for the development of equiaxed grains, whereas both CaO and MgO promote the development of platelike grains. By controlling the molar ratio of additives, it is pos- sible to obtain different microstructures. With SiO2-MgO-CaO (molar ratio, 2:1:1) as the additives and nano a-Al203 powders as the seed, microcrystalline corundum abrasives with hexagonal platelets were obtained using sol-gel process by sintering at 1300℃ for 0.5 h. The average diameter and thickness of hexagonal platelets are 1.38 μm and 360 nm respectively, the sin- gle-particle compressive strength is 26.44 N, and the wear rate is (3.06±=0.21)× 10^-7 mm^3/(N.m). 展开更多
关键词 additives CORUNDUM MICROCRYSTALS sol-gel process platelets compressive strength wear
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Protective Effect of Heparin-coated Circuits on the Platelets during Cardiopulmonary Bypass 被引量:2
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作者 张凯伦 胡志伟 +3 位作者 杨运海 黄如清 范慧敏 孙宗全 《Journal of Huazhong University of Science and Technology(Medical Sciences)》 SCIE CAS 2003年第4期403-406,共4页
To observe the protective effect of heparin coated circuits (HCC) on the platelet function during cardiopulmonary bypass (CPB). 23 patients with heart valve replacement were studied. The system heparin dose was 3 mg... To observe the protective effect of heparin coated circuits (HCC) on the platelet function during cardiopulmonary bypass (CPB). 23 patients with heart valve replacement were studied. The system heparin dose was 3 mg/kg in the control group ( n =15) and heparin coated circuits in the HCC group ( n =8). Platelet count, α granule membrane protein 140 (GMP 140) concentrations were determined before CPB, at 60 min of CPB, 30 and 60 min after protamine administration, first 12 h after CPB, respectively. At end of CPB the arterial filters in the circuits were observed by electron microscopy. The amount of first 12 h postoperative blood loss was measured. There was significant reduction in platelet loss during and after CPB in the HCC group in contrast to the control group during CPB ( P <0.05). During the first 12 h, postoperative blood loss was reduced in the HCC group as compared with that in the control group (218±61 ml, vs. 332±118 ml, P <0.05). Electron microscopy showed that in the HCC group the filter meshes and their fringes were clear and fragments of floccules were occasionally seen, without adherent cells or only few adherent cells on their surfaces, whereas several cellular and fibrous components were found to adhere to the surfaces of the filter meshes in the control group. This study indicates that heparin coated circuits might reduce the platelet loss and activation during CPB and improve hemocompatibility of cardiopulmonary bypass equipment. 展开更多
关键词 cardiopulmonary bypass heparin coated circuits platelet
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Serotonin uptake rates in platelets from angiotensin II-induced hypertensive mice 被引量:2
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作者 Preeti Singh Terry W. Fletcher +2 位作者 Yicong Li Nancy J. Rusch Fusun Kilic 《Health》 2013年第4期31-39,共9页
Angiotensin II (Ang II) is a critical component of the reninangiotensin system that contributes to hypertension. Although platelets in blood from hypertensive subjects have an abnormal biological profile, it is unclea... Angiotensin II (Ang II) is a critical component of the reninangiotensin system that contributes to hypertension. Although platelets in blood from hypertensive subjects have an abnormal biological profile, it is unclear if circulating Ang II influences platelet aggregation or thrombus formation. One of the abnormalities presented to the platelets during hypertension is an elevated plasma concentration of serotonin (5-HT) caused by reduced 5-HT uptake secondary to loss of the 5-HT transporter (SERT) on the platelet plasma membrane. In the current study, we evaluated in vivo platelet function after 7 days of subcutaneous Ang II infusion to establish hypertension in mice and additionally assessed the biology of isolated platelets exposed to Ang II in vitro. The administration of Ang II elevated systolic blood pressure, but markers of platelet activation including P-selectin and PEJon/A staining were not changed. However, the aggregation response to collagen was reduced in isolated platelets from Ang II-infused mice, which also showed reduced 5-HT uptake by SERT. In vitro exposure of isolated platelets to Ang II also resulted in a loss of surface SERT associated with a reduced aggregation response to collagen. These abnormalities were reversed by increasing concentra tions of the Ang II receptor antagonist, valsartan. Interestingly, SERT KO mice failed to fully develop hypertension in response to Ang II infusion and isolated platelets from these animals were insensitive to the anti-aggregatory influence of Ang II. Thus, Ang II blunts the aggregation responses of platelets and the mechanism underlying this action may involve a loss of SERT on the platelet plasma membrane. The latter event depletes intracellular 5-HT in platelets, an event that is associated with reduced aggregation. The widespread use of antihypertensive drugs that target the renin-angiotensin system suggest the potential clinical utility of our findings and emphasize the importance of understanding the impact of Ang II on platelet function. 展开更多
关键词 SEROTONIN ANGIOTENSIN platelet HYPERTENSION
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Platelets and Alzheimer's disease:Potential of APP as a biomarker 被引量:4
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作者 Geneviève Evin Qiao-Xin Li 《World Journal of Psychiatry》 SCIE 2012年第6期102-113,共12页
Platelets are the first peripheral source of amyloid precursor protein(APP). They possess the proteolytic machinery to produce Aβ and fragments similar to those produced in neurons, and thus offer an ex-vivo model to... Platelets are the first peripheral source of amyloid precursor protein(APP). They possess the proteolytic machinery to produce Aβ and fragments similar to those produced in neurons, and thus offer an ex-vivo model to study APP processing and changes associated with Alzheimer's disease(AD). Platelet process APP mostly through the α-secretase pathway to release soluble APP(s APP). They produce small amounts of Aβ, predominantly Aβ40 over Aβ42. s APP and Aβ are stored inα-granules and are released upon platelet activation by thrombin and collagen, and agents inducing platelet degranulation. A small proportion of full-length APP is present at the platelet surface and this increases by 3-fold upon platelet activation. Immunoblotting of platelet lysates detects APP as isoforms of 130 kD a and106-110 kD a. The ratio of these of APP isoforms is significantly lower in patients with AD and mild cognitive impairment(MCI) than in healthy controls. This ratio follows a decrease that parallels cognitive decline andcan predict conversion from MCI to AD. Alterations in the levels of α-secretase ADAM10 and in the enzymatic activities of α- and β-secretase observed in platelets of patients with AD are consistent with increased processing through the amyloidogenic pathway. β-APP cleaving enzyme activity is increased by 24% in platelet membranes of patients with MCI and by 17% in those with AD. Reports of changes in platelet APP expression with MCI and AD have been promising so far and merit further investigation as the search for blood biomarkers in AD, in particular at the prodromal stage, remains a priority and a challenge. 展开更多
关键词 Alzheimer’s disease platelet BIOMARKER AMYLOID PRECURSOR PROTEIN Aβamyloid Β-AMYLOID PRECURSOR PROTEIN cleaving enzyme SECRETASE Proteasenexin 2
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Effects of Total Flavone of Abelmoschl Manihot L.Medic on the Function of Platelets and Its Mechanism 被引量:4
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作者 郭岩 范丽 +1 位作者 董六一 陈志武 《Chinese Journal of Integrated Traditional and Western Medicine》 2005年第1期57-59,共3页
Objective: To study the effects of total flavone of Abelmoschl Manihot L.Medic (TFA) on the function of platelets and to explore its mechanism. Methods: Rat models of artery-veins bypassing thrombus formation were use... Objective: To study the effects of total flavone of Abelmoschl Manihot L.Medic (TFA) on the function of platelets and to explore its mechanism. Methods: Rat models of artery-veins bypassing thrombus formation were used. The platelets of rabbits were collected. Platelet aggregation was induced by collagen and intracellular calcium ion concentration ([Ca 2+ ]i) was assayed by Fura-2 method. Results: TFA (25, 50, 100 mg/kg) significantly and dose-dependently reduced the weight of thrombus. TFA (0.025, 0.05, 0.1 mg/ml) possessed dose-dependant inhibitory effects on rabbits' platelet aggregation induced by collagen. TFA significantly reduced the resting and CaCl 2-induced increase of free intracellular calcium concentration ([Ca 2+ ]i) in rabbit platelet in vitro . Conclusion: TFA has an antiplatelet effect via the inhibition on the influx of Ca 2+ . 展开更多
关键词 total flavone of Abelmoschl Manihot L. Medic thrombosis platelet aggregation CALCIUM FURA-2
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<i>In Vitro</i>Effect of Soy Isoflavone and Equol on Soluble CD40L Release Stimulated by Ristocetin in Platelets from Postmenopause Women 被引量:2
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作者 Natalia Gonzalez Argelia Garrido +1 位作者 Ingrid Acevedo Luis Valladares 《Journal of Biomedical Science and Engineering》 2015年第1期24-30,共7页
The inhibition of specific flavonoid on the in vitro platelet aggregation induced by collagen, arachidonic acid and thromboxane A2 (TxA2) agonist, seems to be related mostly to their ability to compete for binding to ... The inhibition of specific flavonoid on the in vitro platelet aggregation induced by collagen, arachidonic acid and thromboxane A2 (TxA2) agonist, seems to be related mostly to their ability to compete for binding to the TxA2 receptor (TP). The aim of this study was to analyze the effect of soy isoflavone and equol in terms of inhibiting the platelet aggregation and sCD40L release stimulated by ristocetin, an in vitro-activator of glycoprotein Ib/IX/V, in platelets from postmenopausal women. When platelets were stimulated by 0.75 mg/ml ristocetin, equol (10 μM) exhibited a greater inhibitory activity on platelet aggregation (~68%) than genistein or daidzein. The effect of equol was dependent on the concentration of platelet aggregation agonist. In the presence of ristocetin (0.75 mg/ml, 1.125 mg/ml and 1.5 mg/ml), the inhibitory effect of 10 μM equol was 68% ± 5%, 54% ± 4% and 31% ± 5%, respectively. Equol (10 μM) was a potent inhibitor (~35%) of sCD40L release when stimulated with 1.5 mg/ml ristocetin. However, no significant differences were noted in platelets incubated in the presence of genistein or daidzein and stimulated by ristocetin. On the other hand, SQ29548, a high TP antagonist, also inhibited the sCD40L release stimulated by ristocetin. Finally, 10 μM of genistein, daidzein or equol did not significantly affect the thromboxane B2 production when platelets were incubated with 1.5 mg/ml ristocetin. The relevance of this study was to find that equol exhibits a potent activity by inhibiting ristocetin-induced sCD40L release, suggesting that soy isoflavone has important biological effects on the hemostatic system. However, clinical trials will be necessary to assess the effect of equol on platelet and their impact on inflammatory markers. 展开更多
关键词 platelet sCD40L Phyoestrogen ISOFLAVONE EQUOL
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Effect of Lithium Nitrate on the Structure and Property of α-Al2O3 Platelets Prepared via Solid-state Reaction 被引量:1
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作者 Miao Zhuang Shi Jiangong +3 位作者 Miao Qingyuan Hao Jianwei Zhang Yi Zhang Wenping 《China Petroleum Processing & Petrochemical Technology》 SCIE CAS 2017年第2期8-13,共6页
The α-Al_2O_3 platelets were prepared via solid-state reactions and the effect of the amount of lithium nitrate additive on the property of the platelets was investigated. The ICP results indicated that the high temp... The α-Al_2O_3 platelets were prepared via solid-state reactions and the effect of the amount of lithium nitrate additive on the property of the platelets was investigated. The ICP results indicated that the high temperature calcination process resulted in a large loss of lithium species because of volatilization, but there was still a small amount of residual lithium species in the α-Al_2O_3 platelets. The SEM micrographs showed that lithium nitrate led to decrease in the thickness of α-Al_2O_3 platelets and irregular morphology of aggregates. Pore structures results exhibited that addition of lithium nitrate led to decrease in the pore size and increase in the specific surface area of aggregates of α-Al_2O_3 platelets. The XRD and IR patterns suggested that the residual lithium and aluminum oxide formed LiAl_5O_8. The existence of LiAl_5O_8 was the basic reason for the changed performance of α-Al_2O_3 platelets. 展开更多
关键词 SOLID-STATE REACTION Α-AL2O3 platelets LiNO3 PROPERTY
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Platelets Levels before and after Surgical Intervention in Patients with Oral and Maxillofacial Tumors at MNH, Tanzania 被引量:1
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作者 Jeremiah Moshy Karpal Singh Sohal +1 位作者 Sira Stanslaus Owibingire Arnold Augustino 《Surgical Science》 2015年第1期7-11,共5页
Background: There are documented effects of platelets on the solid tumors which need further study. The elevated platelet counts have been described for majority of cancers. There is inadequate information of effect o... Background: There are documented effects of platelets on the solid tumors which need further study. The elevated platelet counts have been described for majority of cancers. There is inadequate information of effect of benign and malignant oral and maxillofacial tumors on the regulation of platelets. The aim of this study was to investigate the changes in platelet counts among patients with oral and maxillofacial benign and malignant tumors following surgical interventions. Methods: A descriptive postoperative study was done whereby patients with benign and malignant oral and maxillofacial tumors who met the inclusion criteria were included. The included patients were those who had no history of blood transfusion prior, during or after surgery, not on haemoglobin-boosting or bone marrow suppressing medications, not seropositive to human immunodeficiency virus also without clinical findings suggestive of lymphadenopathy, splenomegaly, ecchymosis and petechiae. Demographic data, Platelet counts and haemoglobin levels before and after surgery were documented and analysed by chi-square test and values were considered to be significant if p < 0.05. Results: A total of 61 patients were included in the study. The mean age of participants was 37.03 ± 16.6 years with range of 7 to 77 years. Majority 82.5% (n = 52) had benign tumors with a leading diagnosis of ameloblastoma followed by ossifying fibroma. In general there was an increase of platelet counts following surgery from the mean of 276.38 ± 109.40 K/uL to 308.51 ± 117.24 K/uL. Looking at benign and malignant separately, following surgery there was an increase of platelet counts for benign tumors (278.87 ± 106.37 to 305.96 ± 123.12) but a decrease for malignant tumors group (282.33 ± 147.03 to 232 ± 78.48). The haemoglobin level changed from the mean of 12.60 ± 1.71 g/dl before surgery to 11.69 ± 1.70 g/dl after surgery. Conclusion: The mean postoperative increase in platelet counts in benign and malignant tumors was due to healing process of the wound following surgery while the postoperative decrease in platelets counts in malignant tumors was due to effect of tumor removal which diminished the production of platelets activating factors. Malignant tumors produce platelets activating factors which are necessary for them to grow. Also, the difference in postoperative platelets counts in benign and malignant oral and maxillofacial tumors could be attributed by different biological behavior of benign and malignant tumors and hence different interactions of platelets to these tumors. 展开更多
关键词 Oral MAXILLOFACIAL TUMORS PRE-OPERATIVE platelets LEVELS POST-OPERATIVE platelets LEVELS
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Preparation and Characterization of Bi_4Ti_3O_(12) Platelets by a Novel Low-temperature Molten Salt System 被引量:1
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作者 隋万美 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2009年第2期241-244,共4页
Bismuth titanate (Bi4Ti3O12) platelets were prepared by molten salt method in a new salt system of CaCl2·NaCl at 650-750℃, using bismuth nitrate pentahydrate (Bi (NO3)3·H2O) and titanium butoxide (Ti... Bismuth titanate (Bi4Ti3O12) platelets were prepared by molten salt method in a new salt system of CaCl2·NaCl at 650-750℃, using bismuth nitrate pentahydrate (Bi (NO3)3·H2O) and titanium butoxide (Ti (OC4H9)4) as raw materials. The synthesis temperature of Bi4Ti3O12 platelets was decreased to 650℃ from 900-1100℃. The phase compositions and crystalline morphology of Bi4Ti3O12 platelets were investigated by XRD and SEM. The experimental results indicate that Bi4Ti3O12 platelets containing tetragonal and orthorhombic phase with the size of 1-3μm can be synthesized at 650℃ for 2 h, and the orthorhombic phase becomes the dominant phase at 750℃ for 5 h. The size and proportion of Bi4Ti3O12 platelets increase with the increment of the calcining temperature and holding time. The proportion of platelets increases to about ninety percent, and the platelets grow up to about 3-10μm at 750℃ for 5 h from 1-2μm at 650℃ for 2 h. This technical route provides a new low-temperature molten salt system for preparing platelets by molten salt methods. 展开更多
关键词 CaCl2-NaC1 molten salt Bi4Ti3O12 platelets
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Thermal vibration of functionally graded porous nanocomposite beams reinforced by graphene platelets 被引量:5
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作者 M.H.YAS S.RAHIMI 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2020年第8期1209-1226,共18页
The thermal vibration of functionally graded(FG)porous nanocomposite beams reinforced by graphene platelets(GPLs)is studied.The beams are exposed to the thermal gradient with a multilayer structure.The temperature var... The thermal vibration of functionally graded(FG)porous nanocomposite beams reinforced by graphene platelets(GPLs)is studied.The beams are exposed to the thermal gradient with a multilayer structure.The temperature varies linearly across the thickness direction.Three different types of dispersion patterns of GPLs as well as porosity distributions are presented.The material properties vary along the thickness direction.By using the mechanical parameters of closed-cell cellular solid,the variation of Poisson’s ratio and the relation between the porosity coefficient and the mass density under the Gaussian random field(GRF)model are obtained.By using the Halpin-Tsai micromechanics model,the elastic modulus of the nanocomposite is achieved.The equations of motion based on the Timoshenko beam theory are obtained by using Hamilton’s principle.These equations are discretized and solved by using the generalized differential quadrature method(GDQM)to obtain the fundamental frequencies.The effects of the weight fraction,the dispersion model,the geometry,and the size of GPLs,as well as the porosity distribution,the porosity coefficient,the boundary condition,the metal matrix,the slenderness ratio,and the thermal gradient are presented. 展开更多
关键词 thermal vibration functionally graded(FG) porous material graphene platelet(GPL) Timoshenko beam
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Hexagonal hematite platelets synthesized from pyrite cinders by hydrothermal process 被引量:3
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作者 刘昭成 郑雅杰 《Journal of Central South University》 SCIE EI CAS 2011年第5期1377-1382,共6页
Well-crystallized hexagonal hematite (α-Fe2O3) platelets were synthesized by hydrothermal process, using a highly concentrated ferric hydroxide as precursor. The precursor was prepared by adding ammonia to the ferr... Well-crystallized hexagonal hematite (α-Fe2O3) platelets were synthesized by hydrothermal process, using a highly concentrated ferric hydroxide as precursor. The precursor was prepared by adding ammonia to the ferric sulfate solution which was obtained by leaching pyrite cinders with sulfuric acid. Structure and morphology of the synthesized products were investigated by X-ray diffraction, scanning electron microscope, transmission electron microscope and selected area electron diffraction. The results reveal that the reaction temperature has significant effects on the structure, size and shape of the synthesized hematite particles. Typical hexagonal hematite platelets, about 0.4-0.6 μm in diameter and 0.1 μm in thickness, were prepared at 230 ℃ for 0.5 h. Al^3+, contained in the sulfuric acid leaching solution as an impurity, plays an extremely important role in the formation of hexagonal hematite. In addition, a possible mechanism about the formation of hexagonal hematite platelets was proposed. 展开更多
关键词 HEMATITE Α-FE2O3 pyrite cinders hydrothermal process hexagonal platelets
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