Platelet Mobilization Induced by PAF and Its Role in the Thrombocytosis Triggered by Adrenaline in Rats

1989 ◽  
Vol 62 (04) ◽  
pp. 1107-1111 ◽  
Author(s):  
Hugo C Castro-Faria-Neto ◽  
Patricia T Bozza ◽  
Marco A Martins ◽  
Paulo M F L Dias ◽  
Patricia M R Silva ◽  
...  
Keyword(s):  
Receptor Antagonists ◽  
Blood Samples ◽  
Platelet Counts ◽  
Platelet Number ◽  
Edta Solution ◽  
Web 2086 ◽  
Dependent Mechanism

SummaryThe injection of PAP (6 μg/kg, i. v.) induced, in rats, haemoconcentration accompanied by an increase in the platelet number, as attested by the counts of platelets in blood samples diluted in formalin-free EDTA solution. This increase was significant at 15 min, peaked from 1 to 4 h and returned to basal levels 24 h after the lipid administration. The release of platelets induced by PAP was inhibited dose-dependently by specific PAP receptor antagonists such as WEB 2086 (0.5-2 mg/kg), BN 52021 and 48740 RP (5-25 mg/kg). Furthermore, platelet mobilization was clearly impaired in splenectomized animals stimulated by PAP, whereas thrombocytopenia and haemoconcentration by the same stimulus were intact. It was also noted that a second injection of PAP, 24 h after the initial stimulation with the lipid, failed to induce an increase in platelet counts, indicating autodesensitization. Desensitization to PAP or pretreatment with PAP antagonists clearly prevented the increase in the platelet counts after stimulation by adrenaline (15 μg/kg). These findings suggest that, in rats, PAP can induce release of platelets by a spleen-dependent mechanism and that this lipid may be relevant to the thrombocytosis triggered by adrenaline.

The Effect of Venous Occlusion on the Sequestration of Blood Platelets

1972 ◽  
Vol 28 (03) ◽  
pp. 383-392 ◽  
Author(s):  
J Hladovec ◽  
Z Koleilat ◽  
I Přerovský
Keyword(s):  
Blood Platelets ◽  
Venous Blood ◽  
Venous Occlusion ◽  
Blood Samples ◽  
Pronounced Decrease ◽  
Platelet Counts ◽  
Human Volunteers ◽  
Opposite Change

SummaryThe venous occlusion of all four legs in rats caused a highly significant decrease of platelet counts in venous blood especially after the correction for an opposite change in haematocrit. A very pronounced decrease in platelets was observed in human volunteers after a venostasis in one arm in the blood drawn from the occluded limb just before the release of occlusion. Similar decreases were found after a venostasis of both legs in postocclusion blood samples. The decrease in blood platelets results from temporary sequestration in the occluded limbs. The decreases of platelets after a 10 min occlusion of both legs are more pronounced in patients with post thrombotic states.

A Novel Approach to the Assessment of Variations in the Human Platelet Count

2000 ◽  
Vol 83 (03) ◽  
pp. 480-484 ◽  
Author(s):  
John James ◽  
Dianne Brown ◽  
Gordon Whyte ◽  
Mark Dean ◽  
Colin Chesterman ◽  
...  
Keyword(s):  
Platelet Count ◽  
Seasonal Variation ◽  
Individual Variation ◽  
Human Platelet ◽  
First Report ◽  
Platelet Counts ◽  
Novel Approach ◽  
Platelet Number ◽  
Genetically Determined

SummaryThis is the first report of a method to assess the significance of numerical changes in the platelet count based upon a result exceeding the normal intra-individual variation in platelet numbers. Serial platelet counts from 3,789 subjects were analysed to determine the intra-individual variation in platelet numbers. A platelet count difference of 98 × 109/L in males was found to represent a change that would occur by chance in less than 1 in 1,000 platelet count determinations. Tables to determine the significance of platelet number variations, given N previous observations, are provided at two probability levels. The repeatability of the platelet count was calculated as 0.871 (males) and 0.849 (females) indicating that the heritability of platelet count is high and that the platelet count is predominantly genetically determined. A seasonal variation in platelet count was found with a ‘winter’ versus ‘summer’ difference of 5.10 × 109/L (males) and 5.82 × 109/L (females).

scholarly journals Point-of-care microvolume cytometer measures platelet counts with high accuracy from capillary blood

PLoS ONE ◽  
2021 ◽  
Vol 16 (8) ◽  
pp. e0256423
Author(s):  
William M. Dickerson ◽  
Rebecca Yu ◽  
Helena U. Westergren ◽  
Jonathan Paraskos ◽  
Philipp Schatz ◽  
...  
Keyword(s):  
Point Of Care ◽  
Venous Blood ◽  
Reference Method ◽  
Time Data ◽  
Platelet Recovery ◽  
Blood Samples ◽  
Impedance Analyzer ◽  
Platelet Counts ◽  
Platelet Antibodies ◽  
Care Assessment

Background Point-of-care (PoC) testing of platelet count (PLT) provides real-time data for rapid decision making. The goal of this study is to evaluate the accuracy and precision of platelet counting using a new microvolume (8 μL), absolute counting, 1.5 kg cytometry-based blood analyzer, the rHEALTH ONE (rHEALTH) in comparison with the International Society of Laboratory Hematology (ISLH) platelet method, which uses a cytometer and an impedance analyzer. Methods Inclusion eligibility were healthy adults (M/F) ages 18–80 for donation of fingerprick and venous blood samples. Samples were from a random N = 31 volunteers from a single U.S. site. Samples were serially diluted to test thrombocytopenic ranges. Interfering substances and conditions were tested, including RBC fragments, platelet fragments, cholesterol, triglycerides, lipids, anti-platelet antibodies, and temperature. Results The concordance between the rHEALTH and ISLH methods had a slope = 1.030 and R2 = 0.9684. The rHEALTH method showed a correlation between capillary and venous blood samples (slope = 0.9514 and R2 = 0.9684). Certain interferents changed platelet recovery: RBC fragments and anti-platelet antibodies with the ISLH method; platelet fragments and anti-platelet antibodies on the rHEALTH; and RBC fragments, platelets fragments, triglycerides and LDL on the clinical impedance analyzer. The rHEALTH’s precision ranged from 3.1–8.0%, and the ISLH from 1.0–10.5%. Conclusions The rHEALTH method provides similar results with the reference method and good correlation between adult capillary and venous blood samples. This demonstrates the ability of the rHEALTH to provide point-of-care assessment of normal and thrombocytopenic platelet counts from fingerprick blood with high precision and limited interferences.

Comparative Evaluation of Hematologic Analyzers Advia® 120, Advia® 2120 and Pentra® 120DX for Platelet Counts below 40 X 109/L.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 1256-1256
Author(s):  
Josep M. Jou ◽  
Fulgencio Navalon ◽  
Ester Jiménez ◽  
Maribel Diaz-Ricart ◽  
Rosa Brugues ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Linear Regression ◽  
Reference Method ◽  
Cell Counting ◽  
Average Difference ◽  
Double Labeling ◽  
Blood Samples ◽  
Platelet Counts ◽  
Flow Cytometric Method ◽  
Advia 120

Abstract More aggressive therapies used for treatment of oncohematological malignancies or control of immune responses are resulting in an increased frequency of platelet counts below the 50 x 109/L limit. The recommended reference method for platelet counts was tedious and showed low reproducibility until now. In the last 2 years, flow cytometry based techniques combined with specific monoclonal antibodies (MoAbs) have been accepted as reference method. We have evaluated the accuracy for low platelet counts of several hematologic analyzers currently used in our laboratories. The new reference method approved by ISLH, ICSH y NCCLS is based on double labeling of platelets using MoAbs directed to CD41 and CD61 followed by flow cytometry analysis. Absolute platelet counts are calculated using a ratio with red blod cell (RBC) counts provided by the hematological analyzers. In our studies, 50 blood samples with platelet counts ranging from 1.5 to 39.4 x109/L were processed in duplicate through 1 Advia 2120 (Bayer Diagnostics), 2 Advia 120 (Bayer Diagnostics) and 2 Pentra 120 DX (Horiba-ABX Diagnostics). Advia analyzers use laser-based technology while Pentra analyzers use impedance one for cell counting. All samples were also processed through the reference flow cytometric method, being platelets identified by their double labeling for CD41 and CD61. The minimal number of platelets acquired in the platelet region was established at 1000. Absolute platelet counts were calculated using RBC counts provided by the respective analyzers. All blood samples were processed within 6 hours from phlebotomy. Statistical methods applied included: coefficient of variation (%CV), coefficient of correlation (r ), linear regression, Passing-Bablock (P-B) regression and Bland-Altman test. Precision of each analyzer was obtained by processing in 10 times different blood samples with counts from 4 to 39 x 109/L. Global results were evaluated, though special attention was paid to subgroups of results below or above 20 x 109/L. Correlation between reference values and counts provided by the Advia 2120 was 0.945 with a linear regression of 0.987x+2.9. P-B correlation was good and the average difference was 2.7 x 109/L. In the subgroup of samples with counts below 20 x 109/L correlation was 0.874 with 1.00x+2.7. P-B was correct and the average difference was 2.8 x 109/L. Results with Advia 120 were always similar to those calculated with the Advia 2120, though the average difference was slightly lower with a value of 1.7 x 109/L. Precision (CV) was 16% for platelet count levels at 4 x 109/L, 12% for those at 13 x 109/L and 4% for those at 39 x 109/L. Correlation with Pentra 120 Dx was 0.937 with a linear regression of 0.894x+2.7, the P-B was acceptable with an average difference of 1.2 x 109/L. Correlation index was 0.824 with a linear regression of 0.88x+2.8 for platelet counts below 20 x 109/L, average difference was of 1.4 x 109/L and a correct P-B. Precision (CV) ranged from 26% at 4 x 109/L and 8% at 20 x 109/L platelet counts. Our data demonstrate that hematological analyzers evaluated provided very reliable results at low platelet counts. Advia and Pentra analyzers investigated tend to over calculate the number of platelets (2.5 and 1.4 x109/L respectively). Correlation scattering was slightly superior with the Pentra analyzer. Overall reproducibility for low platelet counts was excellent for both laser and impedance technologies tested.

Dual effects of erdosteine on hemostasis via its different metabolites in young rats

2011 ◽  
Vol 30 (10) ◽  
pp. 1644-1648 ◽  
Author(s):  
Vefik Arica ◽  
Murat Tutanc ◽  
Oktay Hasan Ozturk ◽  
Secil Arica ◽  
Fatmagul Basarslan ◽  
...  
Keyword(s):  
Peripheral Blood ◽  
Peripheral Blood Smear ◽  
International Normalized Ratio ◽  
Saline Group ◽  
Oral Gavage ◽  
Blood Samples ◽  
Platelet Counts ◽  
Group 3 ◽  
Group 2 ◽  
Group 1

Aim: In the study, we examined erdosteine’s effects on platelet functions and coagulation. Materials and methods: A total 29 young albino Wistar rats were divided into four groups. Control rats ( n = 6) were given saline; Group 1 rats ( n = 7) were given 3 mg/kg erdosteine by oral gavage for 3 days; Group 2 rats ( n = 7) were given 10 mg/kg erdosteine by oral gavage for 3 days; and Group 3 rats ( n = 9) were given 30 mg/kg erdosteine for 3 days. Twenty-four hours after the final dose, blood samples were drawn from a portal vein. Prothrombin time (PT), activated partial thromboplastin time (aPTT) and international normalized ratio (INR) were measured, and platelet counts were examined in a peripheral blood smear by light microscopy. Results: PT and INR values of Group 1 increased compared to the controls but did not change in Group 3. Hemostatic parameters were not measured in Group 2 because the blood samples in Group 2’s tubes clotted rapidly. Platelet counts of the peripheral blood from Group 2 were low but were normal in other groups. Conclusion: We have concluded erdosteine may disrupt hemostasis parameters by its different metabolites in patients. Erdosteine has dual effects on hemostasis via its different metabolites, which occur in different doses.

Platelet Factor 3 Activity in Washed Platelets

1973 ◽  
Vol 30 (03) ◽  
pp. 557-566 ◽  
Author(s):  
S Renaud ◽  
P Gautheron ◽  
H Rosenstein
Keyword(s):  
Thin Layer ◽  
Thin Layer Chromatography ◽  
Platelet Rich Plasma ◽  
The Other ◽  
Slow Speed ◽  
Platelet Factor ◽  
Platelet Poor Plasma ◽  
Platelet Counts ◽  
Edta Solution ◽  
Layer Chromatography

SummaryPlatelets collected with an EDTA solution and simply washed in an incomplete Tyrode’s presented clotting times in the recalcification (man and rat) and the Stypven (rat) tests that were practically identical to those of the PRP when slow speed centrifugation was used (800 G in man, 1000 G in rat). This was demonstrated, in 6 pools of 5 rats each and in 6 men, by comparing the clotting activity of the citrated platelet-rich plasma to that of the platelets washed and resuspended in the citrated platelet-poor plasma, for platelet counts ranging from 1 × 105 to 10 × 105/mm3. In contrast, centrifugation of platelets at 3000 G markedly affected these clotting activities, as was shown in an additional study comprising 6 pools of 3 rats.Finally, the clotting activity of platelets totally disrupted by sonication appears to be identical quantitatively in both man and rats to that of the total phospholipids extracted from these platelets and separated from the other lipids by thin-layer chromatography and resuspended in plasma by sonication.

scholarly journals Automated Optical Counting of Blood Platelets

Blood ◽  
1971 ◽  
Vol 38 (4) ◽  
pp. 422-430 ◽  
Author(s):  
GEOFFREY M. BRITTIN ◽  
SHIRLEY A. DEW ◽  
ELVI K. FEWELL
Keyword(s):  
Whole Blood ◽  
Blood Platelets ◽  
Venous Blood ◽  
Human Platelets ◽  
Blood Samples ◽  
Platelet Counts ◽  
Large Numbers ◽  
Significant Difference ◽  
Electronic Method ◽  
Electronic Counting

Abstract We have evaluated the use of an optical particle counter to perform automated platelet counts on whole blood. The erythrocytes were lysed by dilution of whole blood with 2 M urea and the remaining platelets and leukocytes were enumerated by a darkfield microscope optical system that detects light diffracted by them. A suspension of fixed human platelets available commercially was highly satisfactory for standardization. The method gave accurate and reproducible platelet counts, comparable with those of electronic particle counting on venous blood and substantially more reliable platelet counts on thrombocytopenic and finger-puncture blood samples. We believe that errors resulting from the electronic method were caused by technical difficulties of sample handling and not to an intrinsic error in electronic counting. By using the automated optical method we found no significant difference between the platelet counts of capillary and venous blood, although capillary platelet counts had twice the variability of venous counts. The optical technique has important advantages over electronic platelet counting, and its superiority appears to be due to the ability to count platelets in diluted whole blood rather than in plasma. It should prove especially useful in performing the large numbers of platelet counts on thrombocytopenic and finger-puncture blood samples that are increasingly important for management of patients receiving chemotherapy.

scholarly journals Assessment of platelet biology in equine patients with systemic inflammatory response syndrome

2020 ◽  
pp. 104063872098379
Author(s):  
Carolin Ehrmann ◽  
Julia Engel ◽  
Andreas Moritz ◽  
Katja Roscher
Keyword(s):  
Platelet Count ◽  
Platelet Aggregation ◽  
Systemic Inflammatory Response Syndrome ◽  
Inflammatory Response ◽  
Systemic Inflammatory Response ◽  
Controlled Study ◽  
Blood Samples ◽  
Platelet Counts ◽  
Impedance Aggregometry ◽  
Edta Blood

In addition to maintaining hemostasis, platelets have an important role in modulating innate and adaptive immune responses. A low platelet count has been found to be a negative prognostic factor for survival in humans and horses with critical illnesses, such as sepsis or systemic inflammatory response syndrome (SIRS). Decreased platelet aggregation, caused by in vivo activation, has been found in human patients with severe sepsis. In our prospective controlled study, we assessed platelet biology in blood samples from 20 equine SIRS cases and 120 healthy control horses. Platelet variables such as platelet count, large platelet count, clumps, plateletcrit, mean platelet volume, and mean platelet component concentration were analyzed by laser flow cytometry (Advia 2120) from K3EDTA blood and from citrate blood. Hirudin blood samples were analyzed by impedance aggregometry (Multiplate analyzer; Roche) for platelet aggregation, including spontaneous aggregation and aggregation by 4 different agonists: adenosine diphosphate (ADPtest), ADP + prostaglandin E1 (ADPtestHS), arachidonic acid (ASPItest), and collagen (COLtest). SIRS cases had significantly lower platelet counts in K3EDTA blood ( p < 0.0001) compared to control horses. There were no significant differences in aggregation values between SIRS cases and controls. Non-surviving SIRS horses did not have statistically significant lower platelet counts or lower aggregation values for COLtest, ADPtest, or ADPtestHS compared to surviving SIRS horses, although 5 non-survivors were thrombocytopenic.

Exclusion of Thrombocytopenia as a Contraindication for Invasive Radiofrequency Ablation in a Patient with Paroxysmal Atrial Fibrillation by Using Magnesium Anticoagulation Instead of EDTA: Another Case of Anticoagulant-Induced Pseudo-Thrombocytopenia

2015 ◽  
Vol 18 (3) ◽  
pp. 090 ◽  
Author(s):  
Peter Kohlschein ◽  
Dietmar Bänsch ◽  
Katrin Dreißiger ◽  
Peter Schuff-Werner
Keyword(s):  
Atrial Fibrillation ◽  
Magnesium Sulphate ◽  
Exclusion Criterion ◽  
Laboratory Findings ◽  
Blood Samples ◽  
Platelet Counts ◽  
Normal Ranges ◽  
Conventional Drug ◽  
Recurrent Atrial Fibrillation

<p class="p1"><span class="s1">Thrombocytopenia might be an exclusion criterion for invasive radiofrequency catheter ablation; therefore it is necessary to differentiate between pseudo-thrombocytopenia and a low platelet count due to other etiologies.</span></p><p class="p1"><span class="s2">A 69-year-old female presented to the cardiology department with recurrent atrial fibrillation that was resistant to conventional drug treatment. The initial laboratory findings were within the normal ranges, except for low platelet counts that occurred without a specific bleeding history. The reason for thrombocytopenia was anticoagulant-induced in vitro aggregation of platelets in the presence of EDTA as well as in citrated blood samples. As recently communicated, magnesium anticoagulated blood samples prevent platelet aggregation in individuals with anticoagulant-associated pseudo-thrombocytopenia. Although its aggregation-inhibiting effect is known from previous clinical observations, magnesium sulphate has not been introduced as an anticoagulant in analytical medicine.</span></p><p class="p1"><span class="s1">Based on our observations, blood anticoagulated with magnesium sulphate is recommended to verify low routine platelet counts before final clinical decisions are made. </span></p>

The Effect of Sample Storage on Impedance and Optical Platelet Counts

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 4063-4063
Author(s):  
Roger C Munro ◽  
Jeremy Tranter ◽  
Laura Hart ◽  
Ruth Jones ◽  
Ann Benton ◽  
...  
Keyword(s):  
Blood Count ◽  
Clinical Laboratory ◽  
Data Extraction ◽  
Full Blood Count ◽  
Sample Storage ◽  
Blood Samples ◽  
Platelet Counts ◽  
Potential Impact ◽  
Underlying Pathology ◽  
Platelet Structure

Abstract Introduction: Processing blood samples for full blood count may be delayed for a multitude of reasons. There is little published information on the effect of sample storage on platelet count. This study compares the effect of storing normal samples at room temperature (RT) and at 4°C prior to processing using different analysers with different technologies. Sysmex SF 3000 and XE2100 analysers are capable of providing impedance (IMP) platelet counts and the latter can also perform fluorescence based optical (OPT) platelet counts. The Coulter LH750 and the ABX Pentra DX120 use IMP technology with enhanced data extraction techniques and algorithms to eliminate interference. Method: Intravenous blood samples for routine blood counts were taken into 4ml K2 EDTA Greiner Vacuette containers from 20 out-patients and the platelet counts measured at 0, 6 and 24 hrs on Coulter LH750 (IMP), ABX Pentra DX120 (IMP), Sysmex SF3000 (IMP) and Sysmex XE2100 (both IMP and OPT) blood count analysers. Samples were stored at RT. Samples were also processed on the XE2100 following storage at 4°C. Results: Mean changes in platelet counts (n = 20) expressed as percentages of the original value at 0 hrs and paired t-test values of significance are shown in the Table. The most significant changes occurred with the XE2100 where the IMP value increased by 7% over 24 hrs but the OPT value fell by 5%. No significant changes occurred with the Coulter or the ABX analysers at 0 and 24 hrs or with the SF3000 at 6 hrs. 6 hr v 0 hr 24 hr v 0 hr % change p % change p Coulter RT + 0.19 0.873 −0.12 0.908 ABX Pentra DX120 RT + 0.02 0.985 + 0.57 0.380 SF 3000 RT + 1.25 0.281 + 2.52 &lt;0.05 XE 2100 Imp RT + 5.26 &lt;.05 + 7.06 &lt;0.05 XE 2100 Imp 4°C + 3.31 &lt;0.05 + 5.06 &lt;0.05 XE 2100 Opt RT −2.20 &lt;0.0 −5.32 &lt;0.05 XE 2100 Opt 4°C + 2.30 &lt;0.05 −0.40 0.750 EDTA exposure and the formation of membrane lesions during sample storage leads to changes in platelet structure, volume, function and shape due to decreased optical density and the beginning of degranulation. All these have a potential impact on the accurate assessment of platelet numbers. If these numbers are to be used accurately as thresholds for platelet transfusion or for monitoring progressive loss or increases of platelets associated with underlying pathology, it is vital that the pre-analytical limitations of current analysers are fully understood. The way in which discriminators are used on various analysers to make distinction between the characteristics of platelets and other blood cells in individual, stored samples will vary in their effectiveness. Conclusions: Our data indicate that various combinations of pre-analytical sample storage and analyser technology should be considered as potential influences on the outcome of platelet counting in the clinical laboratory.

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