ABNORMALITIES OF CYTOPLASMIC [Ca++] IN PLATELETS FROM UREMIC PATIENTS STUDIED WITH AEQU0RIN AND INDO-1

1987 ◽  
Author(s):  
J A Ware ◽  
B A Clark ◽  
M Smith ◽  
E W Salzman
Keyword(s):  
Normal Donor ◽  
Ionophore A23187 ◽  
Platelet Surface ◽  
Surface Receptors ◽  
Prolonged Bleeding ◽  
Prolonged Bleeding Time ◽  
Hemorrhagic Tendency ◽  
Uremic Patients ◽  
Plasma Factors

Uremic patients have a hemorrhagic tendency, often with prolonged bleeding times and abnormalities of platelet function in vitro. Whether these defects result from plasma factors, abnormalities in platelet surface receptors, or intracellular mediators is unknown. Accordingly, blood was obtained from 16 patients with severe uremia (BUN >90), and platelets were washed, loaded with aequorin or indo-1, gel-filtered, and resuspended in either plasma or buffer. Of the 16 patients, 4 had template bleeding times greater than 12 minutes, but platelet aggregation in plasma was not consistently impaired. However, the rise in cytoplasmic [Ca++] in response to the Ca++-ionophore A23187 or ADP in aequorin-loaded platelets from the 4 patients with long bleeding times was much lower than in uremic patients with normal bleejljLng times or in normal volunteers. The reduced [Ca++] response was associated with decreased aggregation of gel-filtered platelets in buffer. Prolonged bleeding time was less consistently correlated with decreased responses to epinephrine or arachidonate. Suspending washed aequorin-loaded uremic platelets in normal plasma for 10-20 min did not reverse the decreased agonist-induced rise in [Ca++]; platelets from a normal donor resuspended in uremic pla^iya responded normally. The agonist-induced rise in [Ca++] shown by indo-1 was not abnormal in patients with prolonged bleeding times; however, uremic patients generally had higher indo-l-indicated basal platelet cytoplasmic [Ca++] than normal. We conclude that the hemorrhagic tendency in some patients with uremia (|s associated with abnormal intracellular platelet [Ca++] regulation marked by elevated resting [Ca++] and a decreased rise in cytoplasmic [Ca++] in response to certain agonists; this latter abnormality appears to be correlated with prolonged bleeding times.

scholarly journals Abnormalities of cytoplasmic Ca2+ in platelets from patients with uremia

Blood ◽  
1989 ◽  
Vol 73 (1) ◽  
pp. 172-176 ◽  
Author(s):  
JA Ware ◽  
BA Clark ◽  
M Smith ◽  
EW Salzman
Keyword(s):  
Platelet Function ◽  
Adenosine Diphosphate ◽  
Normal Donor ◽  
Ionophore A23187 ◽  
Platelet Activity ◽  
Platelet Surface ◽  
Factors Affecting ◽  
Prolonged Bleeding ◽  
Uremic Patients

Abstract Uremic patients have a hemorrhagic tendency, often associated with prolonged bleeding times and decreased platelet function in vitro. Whether these defects result from abnormalities in plasma factors affecting platelet activity, platelet surface receptors, intracellular platelet mediators, or other aspects of platelet behavior is unknown. To examine the possibility that the abnormality in platelet function may result from aberrations in Ca2+ homeostasis, blood was obtained from 29 patients with severe uremia. The platelets were washed, loaded with the Ca2+ -sensitive probes indo-1 and aequorin, gel-filtered, and resuspended in either plasma or buffer. Of the 29 patients, seven had template bleeding times prolonged to 11 minutes or more, but platelet aggregation in plasma was not consistently impaired in these patients. However, in aequorin-loaded platelets from the patients with long bleeding times, the highest elevation of cytoplasmic calcium [( Ca2+]i) in response to the Ca2+ ionophore A23187, arachidonate, adenosine diphosphate (ADP), or epinephrine was lower than that seen in platelets from both uremic patients with less prolonged bleeding times and normal volunteers. The reduced [Ca2+]i response was associated with decreased aggregation of gel-filtered platelets suspended in buffer. Suspending washed aequorin-loaded uremic platelets in normal plasma for 20 minutes did not reverse the decreased agonist-induced rise in [Ca2+]i; platelets from a normal donor resuspended in uremic plasma aggregated and produced a normal increase in [Ca2+]i in response to agonists. We conclude that the platelet defect seen in some patients with uremia is associated with a decreased rise in platelet [Ca2+]i after stimulation and that this is a manifestation of an intrinsic platelet defect.

scholarly journals Abnormalities of cytoplasmic Ca2+ in platelets from patients with uremia

Blood ◽  
1989 ◽  
Vol 73 (1) ◽  
pp. 172-176
Author(s):  
JA Ware ◽  
BA Clark ◽  
M Smith ◽  
EW Salzman
Keyword(s):  
Platelet Function ◽  
Adenosine Diphosphate ◽  
Normal Donor ◽  
Ionophore A23187 ◽  
Platelet Activity ◽  
Platelet Surface ◽  
Factors Affecting ◽  
Prolonged Bleeding ◽  
Uremic Patients

Uremic patients have a hemorrhagic tendency, often associated with prolonged bleeding times and decreased platelet function in vitro. Whether these defects result from abnormalities in plasma factors affecting platelet activity, platelet surface receptors, intracellular platelet mediators, or other aspects of platelet behavior is unknown. To examine the possibility that the abnormality in platelet function may result from aberrations in Ca2+ homeostasis, blood was obtained from 29 patients with severe uremia. The platelets were washed, loaded with the Ca2+ -sensitive probes indo-1 and aequorin, gel-filtered, and resuspended in either plasma or buffer. Of the 29 patients, seven had template bleeding times prolonged to 11 minutes or more, but platelet aggregation in plasma was not consistently impaired in these patients. However, in aequorin-loaded platelets from the patients with long bleeding times, the highest elevation of cytoplasmic calcium [( Ca2+]i) in response to the Ca2+ ionophore A23187, arachidonate, adenosine diphosphate (ADP), or epinephrine was lower than that seen in platelets from both uremic patients with less prolonged bleeding times and normal volunteers. The reduced [Ca2+]i response was associated with decreased aggregation of gel-filtered platelets suspended in buffer. Suspending washed aequorin-loaded uremic platelets in normal plasma for 20 minutes did not reverse the decreased agonist-induced rise in [Ca2+]i; platelets from a normal donor resuspended in uremic plasma aggregated and produced a normal increase in [Ca2+]i in response to agonists. We conclude that the platelet defect seen in some patients with uremia is associated with a decreased rise in platelet [Ca2+]i after stimulation and that this is a manifestation of an intrinsic platelet defect.

scholarly journals Congenital Vascular Defect Associated with Platelet Abnormality and Antihemophilic Factor Deficiency

Blood ◽  
1960 ◽  
Vol 15 (6) ◽  
pp. 807-829 ◽  
Author(s):  
GIOVANNI RACCUGLIA ◽  
JAMES V. NEEL ◽  
Ruth T. Davidson ◽  
Mary Jane Ussery
Keyword(s):  
Bleeding Time ◽  
A Priori ◽  
Dominant Gene ◽  
Hemorrhagic Diathesis ◽  
Prolonged Bleeding ◽  
Prolonged Bleeding Time ◽  
Factor Deficiency ◽  
Hemorrhagic Tendency ◽  
Vascular Defect ◽  
Antihemophilic Factor

Abstract 1. A kindred of 311 individuals, many members of which are affected by a hemorrhagic diathesis, has been described. 2. The variability in the manifestations of this diathesis is extreme. In its fullest expression the disease is characterized by a prolonged bleeding time with evidence of a morphologic defect in the platelets, and a deficiency in antihemophilic globulin. Some possibly affected individuals exhibit only a prolonged bleeding time, while, on the other hand, the clinically most severely affected individual, with AHF levels on several occasions of 5 to 10 per cent, has not been observed by us to have a prolonged bleeding time, although his platelets are morphologically abnormal. 3. Genetic analysis suggests that the hemorrhagic tendency is determined by a single dominant gene of variable penetrance and expressivity. 4. No satisfactory explanation can be developed on the basis of these studies for the association between platelet abnormality and AHF deficiency. More specifically, it is impossible to conclude whether the platelet defect is precursor to the AHF deficiency, or whether—as on a priori grounds seems less likely—this is an example of true genetic pleiotropy. 5. The terminologic chaos which afflicts the literature on hemorrhagic diatheses characterized by a prolonged bleeding time is discussed in the light of the findings in this one large kindred, and suggestions are advanced for minimizing confusion based on terminology alone.

scholarly journals "Impotent" Platelets in Albinos With Prolonged Bleeding Times

Blood ◽  
1972 ◽  
Vol 39 (4) ◽  
pp. 490-499 ◽  
Author(s):  
Harold M. Maurer ◽  
James A. Wolff ◽  
Sue Buckingham ◽  
Arthur R. Spielvogel
Keyword(s):  
Platelet Aggregation ◽  
Adenosine Diphosphate ◽  
Bleeding Tendency ◽  
Prolonged Bleeding ◽  
Prolonged Bleeding Time ◽  
Normal Platelet ◽  
Tryptophan Metabolites ◽  
History Of

Abstract Functional, biochemical, and morphologic platelet abnormalities are reported in four children with the syndrome of albinism, mild bleeding tendency, prolonged bleeding time, and normal platelet count. In these children, primary platelet aggregation with adenosine diphosphate occurred normally, but secondary aggregation was impaired. Collagen and norepinephrine produced almost no platelet aggregation. Platelet content of serotonin (5-HT) was markedly reduced, and uptake and retention of 5-HT by the platelets in vivo and in vitro was poor. In one child who was given a tryptophan load, urinary tryptophan metabolites were normal, suggesting that there was no evidence of a block in the 5-HT synthetic pathway in the gastrointestinal tract. Electron microscopy revealed an absence of densely osmophilic granules in 5-HT poor platelets. Platelets from other albinos with no history of bleeding contained normal amounts of 5-HT and densely osmophilic granules.

scholarly journals Patients with a prolonged bleeding time and normal aggregation tests may have storage pool deficiency: studies on one hundred six patients

Blood ◽  
1987 ◽  
Vol 70 (3) ◽  
pp. 620-623 ◽  
Author(s):  
HK Nieuwenhuis ◽  
JW Akkerman ◽  
JJ Sixma
Keyword(s):  
Platelet Count ◽  
Bleeding Time ◽  
Bleeding Tendency ◽  
Von Willebrand's Disease ◽  
Common Disorder ◽  
Storage Pool ◽  
Prolonged Bleeding ◽  
Prolonged Bleeding Time ◽  
Platelet Serotonin

Abstract One hundred six patients with storage pool deficiency (SPD) were studied with respect to platelet count, bleeding time, total platelet ATP and ADP, platelet serotonin, and in vitro aggregation. The diagnosis of SPD was made on basis of a prolonged bleeding time, a decreased total platelet ADP, and a diminished level of serotonin. Fifty-one patients from 34 unrelated families had congenital SPD, and 55 patients had acquired SPD. Congenital SPD was a common disorder in patients with a lifelong bleeding tendency and a prolonged bleeding time. The frequency in this group of patients was 18%, about one-half the frequency of von Willebrand's disease (vWd). Twenty-three percent of all patients had normal aggregation responses to ADP, epinephrine, and collagen; 33% had aggregation tracings typical for a secretion defect; and 44% had miscellaneous aggregation abnormalities. These findings indicate that SPD is common, heterogeneous, and not necessarily associated with in vitro aggregation abnormalities.

Sustained Bleeding after a leech Bite in the Apparent Absence of Hirudin

1989 ◽  
Vol 61 (03) ◽  
pp. 366-369 ◽  
Author(s):  
R Munro ◽  
F O P Hechtel ◽  
R T Sawyer
Keyword(s):  
Platelet Aggregation ◽  
Bleeding Time ◽  
Medicinal Leech ◽  
Bite Wound ◽  
Apparent Absence ◽  
Coagulation Parameters ◽  
Prolonged Bleeding ◽  
Prolonged Bleeding Time ◽  
Human Volunteers

SummaryThe bite of the medicinal leech bleeds for many hours. For decades it has been assumed that the remarkably prolonged bleeding time of a leech bite wound is due to hirudin, a specific anti-thrombin secreted by the leech during feeding. By measuring haematological parameters of blood oozing from a leech bite wound on 15 different occasions in 7 human volunteers, we demonstrate that the hirudin-sensitive coagulation parameters, including thrombin-induced platelet aggregation, are prolonged for only 15 min, after which they return to normal. This suggests that excess hirudin secreted by the leech is washed out during this period. However, bleeding from the leech bite wound persists for a mean of 10 h. Platelets in smears of exuding blood show no evidence of spontaneous aggregation, but in vitro platelet aggregation can be induced by exogenous collagen at any time. In view of sustained bleeding in the apparent absence of hirudin, attention is focussed onto an unsuspected factor or factors which may better explain the prolonged bleeding phenomenon.

UREMIC PLASMA, AFTER INFUSION OF DESMOPRESSIN, IMPROVES THE INTERACTION OF NORMAL PLATELETS WITH VESSEL SUBENDOTHELIUM

1987 ◽  
Author(s):  
R Castillo ◽  
G Escolar ◽  
J Monteagudo ◽  
A Cases ◽  
M Garrido ◽  
...  
Keyword(s):  
Bleeding Time ◽  
Surface Coverage ◽  
Glass Beads ◽  
Aggregate Formation ◽  
Perfusion System ◽  
Prolonged Bleeding Time ◽  
Perfusion Studies ◽  
Platelet Aggregate ◽  
Uremic Patients

Desmopressin (DDAVP) shortened the bleeding time and increased the platelet retention on glass beads and the platelet interaction on subendothelium measured by the Baumgartner perfusion system in 11 uremic patients in whom the three tests were abnormal previous to the treatment (1).Patients were chosen at random out of a group of 30 with prolonged bleeding time and decreased platelet retention on glass beads. All tests were performed on blood drawn before and one and six hours after a single dose of DDAVP (0.4 μg/kg body weight). Perfusion experiments were carried out at a shear rate of 800 sec-1.Levels of VIII:C, VIIIR:Ag and RiCof were at the upper limit of normality before DDAVP and significantly increased one hour after treatment. The multimeric structure of vWF in pretreatment plasma was normal ; one hour after DDAVP larger multimers appeared.After injection of DDAVP, the perfusion studies using reconstituted blood with uremic PPP in presence of isolated normal platelets and washed red cells, showed a statistically increased surface coverage and platelet aggregate formation on subendothelium (p < 0.05 respectively when compared to the pretreatment values). In the same perfusion assays, the in vitro addition to pretreatment plasmas of 1 u/ml of purified vWF with normal multimeric structure, or purified VIII:C and vWF (1 u/ml each) did not modify the decreased platelet interaction on subendothelium.These results confirm the shortening of bleeding time by DDAVP in uremic patients and reveal an increase of platelet interaction on vessel subendothelium mediated by a factor present in PPP. Besides, they show that the effect of DDAVP in these patients is not due to the quantitative increase of the plasmatic vWF and FVIII.(1) Blood, 68, 2:337-342, 1986.

scholarly journals Platelet Apoptosis Can Be Triggered Bypassing the Death Receptors

2019 ◽  
Vol 25 ◽  
pp. 107602961985364
Author(s):  
Valery Leytin ◽  
Armen V. Gyulkhandanyan ◽  
John Freedman
Keyword(s):  
Surface Membrane ◽  
Calcium Ionophore ◽  
Death Receptors ◽  
Calcium Ionophore A23187 ◽  
Ionophore A23187 ◽  
Extrinsic Pathway ◽  
Platelet Surface ◽  
Surface Receptors ◽  
Platelet Apoptosis ◽  
Von Willebrand

In nucleated cells, the extrinsic pathway of the programmed cell death (apoptosis) is triggered by interaction of death ligands of the tumor necrosis factor superfamily with the death receptors on external cell surface membrane. In this review, we present evidence that, in contrast to nucleated cells, apoptosis in anucleate platelets can be induced through bypassing the death receptors, using instead specific receptors on the platelet surface mediating platelet activation, aggregation, and blood coagulation. These platelet surface receptors include the protease-activated receptor 1 of thrombin and glycoproteins IIbIIIa and Ibα, receptors of fibrinogen, and von Willebrand factor. The pro-apoptotic BH3 mimetic ABT-737 and calcium ionophore A23187 also trigger platelet apoptosis without using death receptors. These agents induce the intrinsic pathway of platelet apoptosis by direct targeting mitochondrial and extra-mitochondrial apoptotic responses.

scholarly journals The Hemostatic Defect of Uremia

Blood ◽  
1956 ◽  
Vol 11 (12) ◽  
pp. 1059-1066 ◽  
Author(s):  
CAMILO LARRAIN ◽  
EDWARD ADELSON
Keyword(s):  
Renal Insufficiency ◽  
Bleeding Time ◽  
Anticoagulant Effect ◽  
Clotting Time ◽  
Prolonged Bleeding ◽  
Prolonged Bleeding Time ◽  
Acute Renal Insufficiency ◽  
Plasma Factors

Abstract The abnormalities of the hemostatic mechanism in three consecutive patients with acute renal insufficiency have been studied. In every case a prolonged clotting time in silicone and a prolonged bleeding time were found. In two cases defective prothrombin consumption was also present. Coagulation studies revealed no significant deficiency of plasma factors, no serious deficiency of platelet numbers or function and no well-defined anticoagulant effect to explain the changes. All three cases developed significant clinical bleeding at some time during the course of the renal insufficiency.

Surface Sialic Acid Prevents Loss of GPIbα during Platelet Storage and Rescues In Vivo Survival of Murine Platelets.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 138-138 ◽  
Author(s):  
Gerard Jansen ◽  
Emma C. Josefsson ◽  
John H. Hartwig ◽  
Karin M. Hoffmeister
Keyword(s):  
Flow Cytometry ◽  
Sialic Acid ◽  
Shape Change ◽  
Platelet Surface ◽  
Integrin Αiibβ3 ◽  
Surface Receptors ◽  
Platelet Survival ◽  
Platelet Receptor

Abstract Platelet processing and storage are associated with platelet lesion, e.g. shape change, activation, release reaction and apoptosis, which is partially due to loss of surface receptors. Surface sialic acid is considered to be a key determinant for the survival of circulating blood cells and glycoproteins. However, its role in platelet receptor loss and platelet survival is unclear. In this study, the relationship between surface sialic acid and platelet receptor loss was investigated in vitro and in vivo. Murine platelets stored at room temperature for 6 hours lost surface sialic acid, as evidenced by flow cytometry using FITC conjugated RCA I lectin, which recognizes exposed galactose residues. This loss correlated with a 30–60% loss of surface receptors GPIbα and GPV, but not GPIX and integrin αIIbβ3, as measured by flow cytometry. Treatment of murine platelets with the neuraminidase (NA) substrate fetuin partially decreases the loss of GPIbα and GPV to 10–20%. In vitro, sialic acid was cleaved from the platelet surface by adding NA (α2-3,6,8-NA (V. cholerae) or α2-3,6,-NA (C. perfringens)) to murine platelets. Removal of sialic acid correlated with the removal of 50–60% of surface GPIbα and GPV, but not GPIX and integrin αIIbβ3. Addition of fetuin, or the more specific NA inhibitor 2,3-dehydro-2-deoxy-, sodium salt (DANA), completely prevented this loss, as determined by both flow cytometry and Western blot analysis. Murine platelets treated with α2-3,6,8-NA (V. cholerae) ± the addition of DANA were labeled with the green dye CMFDA and transfused into age-, strain- and sex-matched C57BL/6 mice to measure platelet survival. NA-treated platelets were cleared within minutes after transfusion, whereas the addition of DANA rescued platelet survival to control-count increments. Our study shows that inhibiting the loss of surface sialic acid prevents platelet surface GPIbα and GPV loss during storage in vitro and rescues platelet survival in vivo.

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