The appearance of multivesicular structures during platelet activation as observed by scanning electron microscopy

Polasek, J.

doi:10.1016/0049-3848(82)90125-6

Cited by 24 publications

(9 citation statements)

References 7 publications

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“…Correlation of MP count with other parameters. 5 levels and MP count (rs = ,697, P < .Ol), specifically in the larger MP distribution (quadrant IV; r, = .748, P < .01) rather than the smaller (quadrant 111; r, = .04, P > .lo). In the samples centrifuged 7,500g-minute, the correlation between PF3 activity and MP count decreased to r, = .486 (P > .lo).…”

mentioning

confidence: 94%

Vesiculation of platelets during in vitro aging

Bode

Orton

Frye

et al. 1991

Blood

143

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Membranous microparticles (MP) appearing in the supernatant plasma of stored platelet concentrates (PC) were analyzed by flow cytometry. Two populations of MP were arbitrarily delineated by light scatter as larger or smaller than 0.5 micron fluorescent beads. An estimate of MP concentration was obtained by adding a known amount of fluorescent beads to each sample before analysis of a set number of counts on the flow cytometer. The addition of platelet activation inhibitors (prostaglandin E-1, theophylline, and aprotinin) to the anticoagulant during preparation of PC combined with a reduction in surface area of the storage container caused approximately a 40% reduction in the number of MP appearing during storage relative to donor-matched controls. In addition, the inhibited concentrates had 84% less platelet factor 3 (PF3) activity in the supernatant and 61% less released lactic dehydrogenase. A reduction in surface area of the container in the controls partially offset these differences. A significant correlation was found (rs = .748) between PF3 levels and the concentration of larger MP. The inhibitors did not reduce the small number of MP found in stored platelet-poor plasma. Surface antigen analysis showed that the majority of MP in PC were platelet-derived; most were positive for glycoprotein (GP) IIbIIIa (73%) and/or for GPIb (43% to 46%). We conclude that procoagulant MP are released from platelets during storage as a result of platelet activation augmented by interaction of platelets with the bag wall.

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mentioning

confidence: 94%

Vesiculation of platelets during in vitro aging

Bode

Orton

Frye

et al. 1991

Blood

143

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“…Wolf [6] described platelet microparticles (PMPs) first as platelet dust. Since this early description, the budding of vesicles from platelet on adhesion to the vessel wall has been demonstrated by electron microscopy [7]. George et al [8] further characterized PMPs and observed more than 10-fold greater concentrations of PMPs in serum than plasma.…”

mentioning

confidence: 95%

Platelet Microparticles in Immune Thrombocytopenic Purpura in Pediatrics

Tantawy

Matter

Hamed

et al. 2010

Pediatric Hematology and Oncology

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Immune thrombocytopenic purpura (ITP) is one of the most common hemorrhagic disorders in childhood. Platelet microparticles (PMPs) arise with platelet activation with procoagulant activity. Elevated PMP levels in adult ITP were reported to be thrombogenic in certain settings. However, their clinical significance in pediatric ITP was not studied. The aims of this study were to assess PMP levels in ITP in children and adolescents, and its correlation with clinical status and bleeding score. The study included 40 ITP patients (20 acute aged 9 +/- 2.19 years and 20 chronic aged 10.8 +/- 4.7 years) randomly selected from the Hematology Clinic, Children's Hospital, Ain Shams University, Cairo, Egypt, and 30 sex- and age-matched healthy controls aged 9 +/- 3.28 years. Patients were subjected to detailed history, assessment of bleeding score, complete hemogram, cytological bone marrow examination, and PMP quantification in peripheral blood by flow cytometry. Acute ITP patients had significant increase in PMPs, PMP/platelet count, and PMP percent compared to controls (P = .002, P < .0001, P < .0001, respectively) and compared to chronic ITP patients (P < .0001, P < .0001, P < .0001, respectively). PMPs were significantly decreased in chronic ITP patients compared to controls (P = .001), but PMP/platelet and PMP percent showed highly significant increase in chronic ITP (P < .0001). No correlation was evident between PMP levels and platelet count in either group (P > .05). Neither higher bleeding score nor thrombotic manifestations were observed in the studied ITP patients with high PMP levels. Elevated PMP levels may be protective against severe bleeding events in pediatric ITP. The role of PMP studies in deciding the management plan of childhood and adolescent ITP needs further evaluation.

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“…Certain histochemical similarities between discharging platelet secretory granules and pneumocyte type 11, lamellar bodies were pointed out earlier (133,181). Pneumocyte type I1 cells are cuboidal cells located in the alveolar wall of the lungs delivering pulmonary surfactant intraalveolary (182)(183)(184)(185).…”

Section: Platelet Multivesicular Bodies Versus Pneumocyte Type II Mumentioning

confidence: 79%

“…Own studies using only brief osmium exposures in SEM studies or ferrocyanide reduced osmium fixative in TEM studies along with chilling of the specimens traced the origin of platelet multivesicular structures or MVBs to platelet secretory granules (132)(133)(134)(135)(136).…”

Section: Multivesicular Bodies or Structures Of Plateletsmentioning

confidence: 99%

Lysosomal Consept of Platelet Secretion ‐ Revisited

Polasek

1989

European J of Haematology

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Certain morphological and biochemical aspects of platelet secretion are discussed. Based on own experiments and review of the literature a hypothesis is forwarded that platelet secretory granules or rather storage organelles can be viewed as secondary lysosomes participating in platelet endocytosis and exocytosis. Formation of the platelet thromboplastic activity, so called PF3, is linked to the platelet storage organelles disintegration and lypolysis during their exocytosis through the platelet plasma membrane.

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The appearance of multivesicular structures during platelet activation as observed by scanning electron microscopy

Cited by 24 publications

References 7 publications

Vesiculation of platelets during in vitro aging

Vesiculation of platelets during in vitro aging

Platelet Microparticles in Immune Thrombocytopenic Purpura in Pediatrics

Lysosomal Consept of Platelet Secretion ‐ Revisited

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