In Vivo Quantification and Platelet Survival Studies: What is the Best Approach?

1985 ◽  
pp. 135-153 ◽  
Author(s):  
A. P. du Heyns
Keyword(s):  
Platelet Survival ◽  
Survival Studies

INDIUM-111 PLATELET SURVIVAL STUDIES ON PLATELET CONCENTRATES (PCVSTORED FOR UP TO 14 DAYS

1987 ◽  
Author(s):  
S Holme ◽  
W A Heaton ◽  
P Hartman
Keyword(s):  
Survival Data ◽  
In Vitro Assays ◽  
Coefficient Of Determination ◽  
Gamma Model ◽  
Storage Duration ◽  
Platelet Survival ◽  
Indium 111 ◽  
Survival Studies

The effect of extended storage on platelet in vitro and in vivo viability was investigated to determine the reliability and efficacy of Indium-111-oxine radiolabeling of long-term stored platelets. The fitness of various mathematical models for measurement of platelet survival and recovery was also evaluated.33 CPDA-1 PC were prepared and stored for various periods of time (see below) according to standard blood bank methods. The volume of the PC was adjusted to 65-75 mL to prevent pH fall with extended storage. After storage, samples were taken for in vitro assays and for radiolabeling witn Indium-111-oxine using standardized methods. None of the PC had pH<6.3. Afxer reinfusion of the labeled platelets, samples for measurement of radioactivity were taken at three hours and daily for seven days.The uptake {%) of Indium-111 and loss of platelets during the labeling showed no correlation with storage time; the means of the 33 studies were 71±8% and 35±6%, respectively. There was no significant correlation between the parameters and recovery or survival which suggests reliable labeling of nonviable platelets. Excellent fit of the survival data to the multiple hit gamma model was found forpall studies as determined by the coefficient of determination, r 2. The survival curves of platelets stored for one and five days were quite linear as shown by r2 ; with longer storage periods they became more exponential as shown by an increasingly better fit (r2 ) to the log model.Using the gamma model, both in vivo recovery and survival showed a progressive loss with increasing storage duration. This was less evident with the linear model. The loss of in vivo viability paralleled closely a decrease in the in vitro , parameters of platelet quality (discoid shape, hypotonic shock response, ATP content, and oxygen consumption) during storage.In conclusion, this study indicates that extended storage not only yields platelets with reduced recovery, but also platelets with shortened survival.

scholarly journals Simultaneous 51CR AND 14C-Serotonin Platelet Survival Measurements

1977 ◽  
Author(s):  
S. Hanson ◽  
L.A. Harker
Keyword(s):  
Arachidonic Acid ◽  
Factor Viii ◽  
Air Bubbles ◽  
Platelet Destruction ◽  
Platelet Survival ◽  
Platelet Release ◽  
Survival Studies ◽  
Bovine Factor

In vivo platelet reactions resulting in platelet utilization or release of constituents without platelet destruction have been studied in baboons by measuring isotopic disappearance of doubly labeled platelets using 51Cr as the cytoplasmic label to detect destruction and 14C-serotonin as a granular |abel to detect release. In 25 normal animals, the 14C-serotonin platelet survival (14C-SPS) was 6.0 days ± 0.2 compared with a Cr platelet survival (51Cr-PS) of 5.5 days ± 0.2, suggesting about 10% reutilization of the 14C label. Platelet labeling in vivo with 51C-serotonin showed that only 13% ± 2% of the injected activity became platelet bound; the remainder was cleared from the plasma within three hours. The platelets labeled in vivo survived normally (6.0 days ± 0.4). These results indicale that in vivo reutilization of serotonin is not extensive and that the process of labeling platelets with Cr in vitro does not appreciably shorten their survival in vivo. In other studies, animals with doubly labeled platelets received intravenous infusions of thrombin, ionophore R02-2985, arachidonic acid, ADP, collagen, plasmin, streptokinase, endotoxin, bovine factor VIII, and air bubbles. Thrombin or collagen infusions produced rapid, equivalent disappearance of both labels that correlated closely with decreases in platelet counts indicating that platelet destruction is not associated with reuptake of released C-serotonin by ambient circulating platelets. In contrast the infusions of R1I2-2985, plasmin or some studies with endotoxin induced selective disappearance of 51C-serotonin while 51Cr-PS was normal, reflecting platelet release in vivo without platelet destruction. With ADP, arachidonic acid, streptokinase and air bubbles platelets disappeared from the circulation transiently without loss of either label indicating transient platelet sequestration. We conclude that doubly labeled platelet survival studies are useful in characterizing platelet reactions and their pharmacologic alterations in vivo.

The Influence of Ascorbic Acid on Platelet Structure and Function

1975 ◽  
Vol 34 (01) ◽  
pp. 050-062
Author(s):  
Dale H Cowan ◽  
Richard C Graham ◽  
Patricia Shook ◽  
Ronda Griffin
Keyword(s):  
Ascorbic Acid ◽  
Open Channel ◽  
Channel System ◽  
Short Intervals ◽  
Platelet Survival ◽  
Artifactual Changes ◽  
Survival Studies ◽  
And Function ◽  
Induced Aggregation ◽  
Platelet Structure

SummaryTo determine the effect on platelet behavior of transient exposure of platelets to ascorbic acid, studies of platelet function and ultrastructure were done before exposure to ascorbic acid at pH 6.5, during exposure to pH 6.5, and after restoration of pH to pre-acidifìcation levels. The effect of ascorbic acid (A. A.) was compared to that of HCl and citric acid (C. A.). ADP- and collagen-induced aggregation of normal platelets were significantly impaired by both A. A. and C. A. but were less affected by HCl. The release of 14C-serotonin was significantly reduced by each agent. The ultra-structure of normal platelets brought to pH 6.5 by A.A. was normal. After neutralization, there was marked dilatation of the open channel system and loss of the disc shape. When platelets were brought to pH 6.5 by A. A., then neutralized, the aggregates which formed after stimulation by ADP or collagen were smaller than normal, the platelets were less closely approximated, and degranulation was less complete. The data show that exposure of platelets to ascorbic acid for short intervals impairs their function when measured after restoration of pH to levels compatible with maximal responses. Platelet survival studies using autologous platelets labelled with 51Cr in the presence or absence of ascorbic acid showed that the recovery of normal platelets was unaffected by ascorbic acid, whereas recovery of platelets from patients with idiopathic thrombocytopenic purpura, idiopathic thrombocythemia, and alcohol-related thrombocytopenia was markedly reduced. The injury resulting from the use of ascorbic acid in preparing platelets for studies of platelet survival in patients with disorders affecting platelets may impair the recovery of the cells, resulting in artifactual changes in the survival studies.

Partially desulfated heparin modulates the interaction between anti-protamine/heparin antibodies and platelets

2016 ◽  
Vol 115 (02) ◽  
pp. 324-332 ◽  
Author(s):  
Rabie Jouni ◽  
Heike Zöllner ◽  
Ahmad Khadour ◽  
Jan Wesche ◽  
Anne Grotevendt ◽  
...  
Keyword(s):  
Platelet Activation ◽  
Platelet Factor ◽  
Standard Drug ◽  
Platelet Surface ◽  
Minimal Impact ◽  
Platelet Survival ◽  
Heparin Complexes ◽  
The Impact

SummaryProtamine (PRT) is the standard drug to neutralise heparin. PRT/heparin complexes induce an immune response similar to that observed in heparin-induced thrombocytopenia (HIT). Partially desulfated heparin (ODSH) was shown to interfere with anti-platelet factor 4/heparin antibodies (Abs), which are responsible for HIT. In this study, we analyse the impact of ODSH on the interaction between anti-PRT/heparin Abs and platelets. The ability of ODSH to prevent anti-PRT/heparin Ab-induced platelet destruction in vivo was investigated using the NOD/ SCID mouse model. ODSH improved platelet survival in the presence of PRT, heparin and anti-PRT/heparin Abs (median platelet survival after 300 minutes (min) with 20 μg/ml ODSH: 75 %, range 70–81 % vs without ODSH: 49%, range 44–59%, p=0.006). Furthermore, when ODSH was applied 60 min after Ab injection platelet survival was improved (median platelet survival after 300 min with ODSH: 83 %, range 77–93 % vs without ODSH: 59 %, range 29–61 %, p=0.02). In in vitro experiments ODSH inhibited platelet activation at concentrations > 16 μg/mL (p< 0.001), as well as PRT/heparin complex binding to platelets (mean fluorescence intensity [MFI] without ODSH: 85 ± 14 vs with ODSH: 15 ± 0.6, p=0.013). ODSH also displaced pre-bound complexes from the platelet surface (MFI without ODSH: 324 ± 43 vs with 32 μg/ml ODSH: 53 ± 9, p< 0.001). While interfering with platelet activation by anti-PRT/heparin Abs, up to a concentration of 16 μg/ml, ODSH had only minimal impact on neutralisation of heparin by PRT. In conclusion, our study shows that ODSH is able to inhibit platelet activation and destruction suggesting a potential clinical use to reduce anti-PRT/heparin Ab-mediated adverse effects.

scholarly journals Thrombocytopenia in septicemia: the role of disseminated intravascular coagulation

Blood ◽  
1980 ◽  
Vol 56 (1) ◽  
pp. 88-92 ◽  
Author(s):  
PB Neame ◽  
JG Kelton ◽  
IR Walker ◽  
IO Stewart ◽  
HL Nossel ◽  
...  
Keyword(s):  
Disseminated Intravascular Coagulation ◽  
Gel Chromatography ◽  
Severe Thrombocytopenia ◽  
Intravascular Coagulation ◽  
Platelet Counts ◽  
Normal Platelet ◽  
Platelet Survival ◽  
Possible Cause

Abstract The mechanism of isolated thrombocytopenia in septicemia is unknown, but compensated disseminated intravascular coagulation (DIC) has been suggested as a possible cause. To investigate this possibility, platelet counts and sensitive assays for in vivo thrombin and plasmin generation, including fibrinogen gel chromatography and fibrinopeptide A (FPA) assays, were obtained on 31 septicemic patients. Fifteen of 17 patients with gram-negative septicemia and 8 of 14 patients with gram- positive septicemia had thrombocytopenia. Platelet survival studied demonstrated a decreased platelet survival. In 11 of 12 patients with severe thrombocytopenia (platelet count less than 50,000mul), there was laboratory evidence of intravascular coagulation. In contrast, there was little evidence of intravascular coagulation in 8 of 11 patients with moderate thrombocytopenia (platelet counts 50,000 to less than 150,000/mul) or in 7 of 8 patients with normal platelet counts. This report indicates that while DIC accompanies thrombocytopenia in many patients with severe thrombocytopenia, there is frequently little evidence for intravascular coagulation in patients with moderate thrombocytopenia. It is apparent that factors other than intravascular thrombin must play a role in producing the thrombocytopenia of septicemia.

scholarly journals In vivo survival studies of 51Cr-labeled methyl acetimidate treated erythrocytes in patients with sickle cell disease

Blood ◽  
1980 ◽  
Vol 56 (6) ◽  
pp. 1041-1047 ◽  
Author(s):  
TG Gabuzda ◽  
TL Chao ◽  
MR Berenfeld ◽  
T Gelbart
Keyword(s):  
Sickle Cell Disease ◽  
Survival Time ◽  
Sickle Cell ◽  
Clinical Testing ◽  
Cell Disease ◽  
Show Evidence ◽  
Survival Studies ◽  
Circulating Antibody

Abstract Studies of the survival time of 51Cr labeled erythrocytes treated in vitro with methyl acetimidate (MAI) were conducted in 13 patients with sickle cell disease in order to assess the suitability of this antisickling agent for more extensive clinical testing. In comparison with previously measured control values (average t1/2 8.4 +/- 1.1 days a), the survival time of the treated erythrocytes in 10 of the patients who were not transfused was initially prolonged (average t1/2 24.4 +/- 4.6 days). However, 5 of the 13 patients studied developed circulating antibody against the MAI treated erythrocytes, markedly reducing the survival time of MAI treated erythrocytes in subsequent studies. Two patients, each challenged 3 times with infused MAI treated erythrocytes, failed to show evidence of antibody production, suggesting that not all subjects become immunized even after repeated exposure. In spite of many other promising properties of MAI as an antisickling agent of potential value, consideration of its use in further clinical testing must depend on successful avoidance of immunization in patients receiving infusions of treated erythrocytes.

IN VIVO STUDIES ON RED CELLS AND PLATELETS STORED IN HALFSTRENGTH CITRATE

1987 ◽  
Author(s):  
C Prewse ◽  
K Bell ◽  
B Griffin
Keyword(s):  
Factor Viii ◽  
Coagulation Factor ◽  
Red Cells ◽  
In Vivo Studies ◽  
Dramatic Improvement ◽  
Half Strength ◽  
Survival Studies ◽  
Cellular Components

We have previously shown that donation of blood into anticoagulants containing half the normal amount of citrate results in a dramatic improvement in the stability of coagulation factor VIII and has no adverse effect on the in vitro qualities of red cells or platelets during storage. To confirm the viability of stored cellular components we are now performing autologous survival studies in healthy volunteers using radiolabelled cells from red cells and platelets stored for 35 and 5 days respectively. Results to date indicate a 24 hour survival of 80% for red cells stored at a haematocrit of 0.70 for 35 days. Infusion of Ill-In oxine labelled platelets after storage for 5 days in full or half-strength citrate gave recoveries of 40% and survivals of 7 days. These encouraging results suggest use of halfstrength citrate may be a route to increasing factor VIII supply without any additional donor recruitment. Further in vitro studies have also been performed on cellular components and reveal adequate in vitro quality for half-strength citrate blood held at room temperature for 20 hours prior to component preparation.

Quantitation of Platelet Adherence to Rabbit Aortae and Platelet Survival After two Injuries with a Balloon Catheter

1979 ◽  
Author(s):  
R.L. Kinlough-Rathbone ◽  
H.M. Groves ◽  
S. Maric ◽  
M.A. Packham ◽  
J.F. Mustard
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Cell ◽  
Muscle Cell ◽  
Balloon Catheter ◽  
Rabbit Aorta ◽  
Platelet Adherence ◽  
Platelet Survival ◽  
Single Balloon

Following a single balloon catheter injury to a rabbit aorta (INJ 1) a monolayer of platelets covers the subendothelium within 10 min, the surface becomes relatively non-reactive to further platelet accumulation and platelet survival is not altered. We have now studied whether a second similar injury (INJ 2) of the non-reactive, smooth muscle cell-rich neointima 7 days after INJ 1 makes the surface of the neointima reactive to platelets or alters platelet survival. 51Cr-platelet adherence to the neointima of aortae subjected to INJ 2 in vitro 7 days after an initial in vivo injury was not significantly different from the adherence following a single in vitro injury (16,600 ± 3100 platelets/mm2 and 27,600 ± 4000 respectively, ρ > 0.2). In vivo adherence of 51Cr-platelets to the surface of rabbit aortae was similar following INJ 1 (0.084 ± 0.009% of the circulate, platelets) and INJ 2 (0.130 ± 0.03%, p > 0.2). Platelet survival after injury to the neointima was not significantly different in animals with an undamaged aortic endothelium (74.6 ± 5.9 hr and 80.2 ± 4.3 hr respectively, ρ > 0.5). Thus, a second injury involving the smooth’ muscle cell-rich neointima that forms after removal of the endothelium with a balloon catheter does not cause more platelets to accumulate than the initial injury, nor shorten platelet survival.

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