Journal•ISSN: 0953-7104
Platelets
Informa
About: Platelets is an academic journal published by Informa. The journal publishes majorly in the area(s): Platelet & Platelet activation. It has an ISSN identifier of 0953-7104. Over the lifetime, 2856 publications have been published receiving 54142 citations.
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TL;DR: Although anucleated, blood platelets are highly organized cells rich in different types of organelles, some of which are at high concentrations, and transport some specific compounds through the whole body.
Abstract: Although anucleated, blood platelets are highly organized cells rich in different types of organelles. Three specific granule populations store different types of constituents, some of which are at high concentrations. Platelets thus transport some specific compounds through the whole body. During circulation, platelets are reactive to various stimuli and release the materials stored in the specific granules. This 'release reaction' is an important step of primary haemostasis. Energy and messengers required for platelet reactivity are provided by mitochondria and the dense tubular system. Each granule population has specific properties concerning both the structure and the role played by the released constituents. Dense granules contain small non-protein molecules that are secreted to recruit other platelets. alpha-Granules contain large adhesive and healing proteins. Lysosomes contain hydrolases able to eliminate the circulating platelet aggregate. The extrusion of storage granules' content to the platelet's environment occurs according to regulated secretion events: movements of granules, apposition and fusion of granule and plasma membranes. Typical platelet disorders resulting from a storage granule abnormality are referred to as a storage pool defect and are characterized by a prolonged bleeding time.
568 citations
TL;DR: It is suggested that MPV response to low-dose collagen may be a useful indicator of platelet propensity to activation, and further studies are warranted to correlate MPV with classical platelet aggregation tests and with the use of Platelet-active drugs.
Abstract: Background: Mean platelet volume (MPV) is increased in patients at high risk for athero-thrombotic diseases. Thus, an elevated MPV may be a risk marker for platelet activation. Methods: Healthy subjects with normal triglyceride (TG) levels (90 - 6 mg/dl; n = 40) or mild hypertriglyceridemia (161 - 79 mg/dl; n = 32) were studied. MPV was measured in fasting blood samples before and after stimulation with collagen (10 w g/ml), and exposure to 4 or 37°C. Samples from the normotriglyceridemic subjects were tested again 4 h after consuming a high-fat drink. Results: Collagen and exposure to 4°C increased MPV, whereas incubation at 37°C lowered MPV regardless of TG level. There was no significant difference in unstimulated MPV between the fasting and the fed states in the normotriglyceridemic subjects (both 7.2 - 0.1 fl; mean - SEM), nor between the latter group and hypertriglyceridemic subjects (7.0 - 0.1 fl). There was a significant negative relation between MPV and fasting TG level. Conclusions: This study s...
421 citations
TL;DR: In this paper, the mean platelet volume as an indicator of platelet activation was used as a criterion for detecting the activation of platelets, and the authors proposed methodological issues.
Abstract: (2003). Mean platelet volume as an indicator of platelet activation: methodological issues. Platelets: Vol. 14, No. 5, pp. 335-336.
343 citations
TL;DR: Among type 2 diabetic patients, MPV is higher in those who have microvascular complications (retinopathy or microalbuminuria), and among non-diabetic patients, it is lower in people who have retinopathy and micro Albuminuria.
Abstract: Aim of the study: To evaluate mean platelet volume (MPV) in type 2 diabetic versus non-diabetic patients, as well as to investigate the associations between MPV and diabetic complications.Materials and methods: This study included 416 patients divided into two groups. Group A comprised 265 type 2 diabetic patients (131 men) with a mean age of 67.4 ± 9.5 years and a mean diabetes duration of 14.5 ± 5.7 years. Group B comprised 151 non-diabetic patients (74 men) with a mean age of 68.6 ± 9.1 years. MPV (blood samples anticoagulated with sodium citrate) was measured in two blood cell counters (Sysmex SF 3000 and Cell-Dyn 3700).Results: MPV was significantly higher (P = 0.01) in group A (14.2 ± 2.2 fl) than in group B (7.1 ± 1.2 fl). In group A MPV was significantly higher (P = 0.043) in patients with retinopathy (15.8 ± 1.3 fl) than in patients without retinopathy (10.9 ± 1.1 fl) and also significantly higher (P = 0.044) in patients with microalbuminuria (15.6 ± 1.2 fl) than in patients without microalbuminu...
322 citations
TL;DR: The expression level of CD40L was shown to be upregulated by phorbol myristate acetate (PMA) in the promegakaryocytic cell line MEG-01 and this study compares the subcellular localization and the regulation of expression of the platelet activation markers CD62P and CD63 with CD40 ligand on the surface of washed human platelets.
Abstract: This study compares the subcellular localization and the regulation of expression of the platelet activation markers CD62P and CD63 with CD40 ligand (CD40L) on the surface of washed human platelets CD40L was expressed upon stimulation with a wide range of platelet activators However, quantitative flow cytometry demonstrated that, as compared with CD62P and CD63, CD40L expression was low Upon stimulation with thrombin receptor-activating peptide (TRAP-6), all activation markers were expressed In contrast, upon stimulation with low concentrations of collagen (1-3 microg/ml), CD40L, but not the granule proteins (CD62P, CD63), were expressed Using immunofluorescence microscopy, a cytoplasmic staining was observed for CD40L, and cytoplasmic localization of CD40L was verified by Western blotting of subcellular platelet fractions The staining of CD40L was different from that of filamentous actin and only little association of CD40L with platelet cytoskeleton was found Surface expression of CD40L was dependent on internal Ca2+ stores and protein kinase C, while the mitogen-activated protein kinases (ERK, p38) or tyrosine kinases were not involved ADP (30 microM)-induced CD40L expression was not inhibited by aspirin In contrast, clopidogrel treatment completely abolished ADP-induced expression of CD40L Finally, the expression level of CD40L was shown to be upregulated by phorbol myristate acetate (PMA) in the promegakaryocytic cell line MEG-01
261 citations