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Sample records for platelet analyzer cpa

  1. Monitoring aspirin therapy with the Platelet Function Analyzer-100

    DEFF Research Database (Denmark)

    Mortensen, Jette; Poulsen, Tina Svenstrup; Grove, Erik Lerkevang

    2008-01-01

    OBJECTIVE: Low platelet response to aspirin has been reported to be associated with a high incidence of vascular events. The reported prevalence of aspirin low-responsiveness varies, which may be explained by poor reproducibility of the methods used to evaluate aspirin response and low compliance....... The Platelet Function Analyzer-100 (PFA-100) is a commonly used platelet function test. We aimed to assess the reproducibility of the PFA-100 and the agreement with optical platelet aggregometry (OPA) in healthy volunteers and in patients with coronary artery disease (CAD) treated with low-dose aspirin....... MATERIAL AND METHODS: Twenty-one healthy volunteers and 43 patients with CAD took part in the study. During treatment with aspirin 75 mg daily, all participants had platelet function assessed in duplicate with the PFA-100 and OPA on 4 consecutive days. Additionally, platelet function was assessed before...

  2. Platelet Function Analyzed by Light Transmission Aggregometry

    DEFF Research Database (Denmark)

    Hvas, Anne-Mette; Favaloro, Emmanuel J

    2017-01-01

    function can also be assessed for hyper-aggregability, but this is less often evaluated. Light transmission aggregometry (LTA) was introduced in the early 1960s and has since been considered the gold standard. This optical detection system is based on changes in turbidity measured as a change in light...... transmission, which is proportional to the extent of platelet aggregation induced by addition of an agonist. LTA is a flexible method, as different agonists can be used in varying concentrations, but performance of the test requires large blood volumes and experienced laboratory technicians as well...

  3. Using the Platelet Function Analyzer-100 for monitoring aspirin therapy

    DEFF Research Database (Denmark)

    Poulsen, Tina Svenstrup; Mickley, Hans; Korsholm, Lars

    2007-01-01

    INTRODUCTION: The aim of the study was to evaluate the test characteristics of the Platelet Function Analyzer-100 (PFA-100) in patients treated with aspirin. METHODS AND RESULTS: The study consisted of two sub-studies. In study 1, 10 patients with ischemic heart disease (IHD) and 10 controls had...... platelet function assessed by optical platelet aggregation and the PFA-100 method in two 5-week periods. Patients with IHD were treated with aspirin 150 mg/day (first 5-week period), and 300 mg/day (second 5-week period), whereas the controls only received aspirin (150 mg/day) during the second 5-week...... period. From the results of study 1, we found that a cut-off value for the PFA-100 collagen/epinephrine cartridge PFA-100 method and optical platelet aggregation was found. Within...

  4. Comparative evaluation of Plateletworks, Multiplate analyzer and Platelet function analyzer-200 in cardiology patients.

    Science.gov (United States)

    Kim, Jeeyong; Cho, Chi Hyun; Jung, Bo Kyeung; Nam, Jeonghun; Seo, Hong Seog; Shin, Sehyun; Lim, Chae Seung

    2018-04-14

    The objective of this study was to comparatively evaluate three commercial whole-blood platelet function analyzer systems: Platelet Function Analyzer-200 (PFA; Siemens Canada, Mississauga, Ontario, Canada), Multiplate analyzer (MP; Roche Diagnostics International Ltd., Rotkreuz, Switzerland), and Plateletworks Combo-25 kit (PLW; Helena Laboratories, Beaumont, TX, USA). Venipuncture was performed on 160 patients who visited a department of cardiology. Pairwise agreement among the three platelet function assays was assessed using Cohen's kappa coefficient and percent agreement within the reference limit. Kappa values with the same agonists were poor between PFA-collagen (COL; agonist)/adenosine diphosphate (ADP) and MP-ADP (-0.147), PFA-COL/ADP and PLW-ADP (0.089), MP-ADP and PLW-ADP (0.039), PFA-COL/ADP and MP-COL (-0.039), and between PFA-COL/ADP and PLW-COL (-0.067). Nonetheless, kappa values for the same assay principle with a different agonist were slightly higher between PFA-COL/ADP and PFA-COL/EPI (0.352), MP-ADP and MP-COL (0.235), and between PLW-ADP and PLW-COL (0.247). The range of percent agreement values was 38.7% to 73.8%. Therefore, various measurements of platelet function by more than one method were needed to obtain a reliable interpretation of platelet function considering low kappa coefficient and modest percent agreement rates among 3 different platelet function tests.

  5. Thromboelastography platelet mapping in healthy dogs using 1 analyzer versus 2 analyzers.

    Science.gov (United States)

    Blois, Shauna L; Banerjee, Amrita; Wood, R Darren; Park, Fiona M

    2013-07-01

    The objective of this study was to describe the results of thromboelastography platelet mapping (TEG-PM) carried out using 2 techniques in 20 healthy dogs. Maximum amplitudes (MA) generated by thrombin (MAthrombin), fibrin (MAfibrin), adenosine diphosphate (ADP) receptor activity (MAADP), and thromboxane A2 (TxA2) receptor activity (stimulated by arachidonic acid, MAAA) were recorded. Thromboelastography platelet mapping was carried out according to the manufacturer's guidelines (2-analyzer technique) and using a variation of this method employing only 1 analyzer (1-analyzer technique) on 2 separate blood samples obtained from each dog. Mean [± standard deviation (SD)] MA values for the 1-analyzer/2-analyzer techniques were: MAthrombin = 51.9 mm (± 7.1)/52.5 mm (± 8.0); MAfibrin = 20.7 mm (± 21.8)/23.0 mm (± 26.1); MAADP = 44.5 mm (± 15.6)/45.6 mm (± 17.0); and MAAA = 45.7 mm (± 11.6)/45.0 mm (± 15.4). Mean (± SD) percentage aggregation due to ADP receptor activity was 70.4% (± 32.8)/67.6% (± 33.7). Mean percentage aggregation due to TxA2 receptor activity was 77.3% (± 31.6)/78.1% (± 50.2). Results of TEG-PM were not significantly different for the 1-analyzer and 2-analyzer methods. High correlation was found between the 2 methods for MAfibrin [concordance correlation coefficient (r) = 0.930]; moderate correlation was found for MAthrombin (r = 0.70) and MAADP (r = 0.57); correlation between the 2 methods for MAAA was lower (r = 0.32). Thromboelastography platelet mapping (TEG-PM) should be further investigated to determine if it is a suitable method for measuring platelet dysfunction in dogs with thrombopathy.

  6. Reference range determination for whole-blood platelet aggregation using the Multiplate analyzer

    NARCIS (Netherlands)

    Peerschke, Ellinor I. B.; Castellone, Donna D.; Stroobants, A. K.; Francis, John

    2014-01-01

    To develop reference ranges for platelet aggregation using the Multiplate analyzer (Roche Diagnostics, Mannheim, Germany) in blood anticoagulated with sodium citrate (Na-citrate), lithium heparin (Li-heparin), or hirudin. The study was performed at three sites on consented, healthy adults (n = 193)

  7. Capital Projects Application (CPA)

    Data.gov (United States)

    General Services Administration — Capital Projects application (CPA) provides users with the ability to maintain project related financial data for Budget Activity (BA) 51, 55, 64, 01, 02, 03, 04....

  8. The use of regression analysis in determining reference intervals for low hematocrit and thrombocyte count in multiple electrode aggregometry and platelet function analyzer 100 testing of platelet function.

    Science.gov (United States)

    Kuiper, Gerhardus J A J M; Houben, Rik; Wetzels, Rick J H; Verhezen, Paul W M; Oerle, Rene van; Ten Cate, Hugo; Henskens, Yvonne M C; Lancé, Marcus D

    2017-11-01

    Low platelet counts and hematocrit levels hinder whole blood point-of-care testing of platelet function. Thus far, no reference ranges for MEA (multiple electrode aggregometry) and PFA-100 (platelet function analyzer 100) devices exist for low ranges. Through dilution methods of volunteer whole blood, platelet function at low ranges of platelet count and hematocrit levels was assessed on MEA for four agonists and for PFA-100 in two cartridges. Using (multiple) regression analysis, 95% reference intervals were computed for these low ranges. Low platelet counts affected MEA in a positive correlation (all agonists showed r 2 ≥ 0.75) and PFA-100 in an inverse correlation (closure times were prolonged with lower platelet counts). Lowered hematocrit did not affect MEA testing, except for arachidonic acid activation (ASPI), which showed a weak positive correlation (r 2 = 0.14). Closure time on PFA-100 testing was inversely correlated with hematocrit for both cartridges. Regression analysis revealed different 95% reference intervals in comparison with originally established intervals for both MEA and PFA-100 in low platelet or hematocrit conditions. Multiple regression analysis of ASPI and both tests on the PFA-100 for combined low platelet and hematocrit conditions revealed that only PFA-100 testing should be adjusted for both thrombocytopenia and anemia. 95% reference intervals were calculated using multiple regression analysis. However, coefficients of determination of PFA-100 were poor, and some variance remained unexplained. Thus, in this pilot study using (multiple) regression analysis, we could establish reference intervals of platelet function in anemia and thrombocytopenia conditions on PFA-100 and in thrombocytopenia conditions on MEA.

  9. Reference intervals for mean platelet volume and immature platelet fraction determined on a sysmex XE5000 hematology analyzer

    DEFF Research Database (Denmark)

    Jørgensen, Mikala Klok; Bathum, L.

    2016-01-01

    Background New parameters describing the platelet population of the blood are mean platelet volume (MPV), which is a crude estimate of thrombocyte reactivity, and immature platelet fraction (IPF), which reflects megakaryopoietic activity. This study aimed to define reference intervals for MPV...... and IPF and to investigate whether separate reference intervals according to smoking status, age or sex are necessary.Methods Blood samples were obtained from subjects participating in The Danish General Suburban Population Study. MPV and IPF measurements were performed by the use of the Sysmex XE-5000...

  10. Biological variation of platelet parameters determined by the Sysmex XN hematology analyzer.

    Science.gov (United States)

    Buoro, Sabrina; Seghezzi, Michela; Manenti, Barbara; Pacioni, Aurelio; Carobene, Anna; Ceriotti, Ferruccio; Ottomano, Cosimo; Lippi, Giuseppe

    2017-07-01

    This study was aimed to define the short- and medium-term biological variation (BV) estimates, the index of individuality and the reference change value (RCV) of platelet count, platelet distribution width, mean platelet volume, platelet larger cell ratio, plateletcrit and immature platelet fraction. The study population consisted of 43 health subjects, who participated to the assessment of medium-term (21 subjects; blood sampling once a week for 5 consecutive weeks) and short-term (22 subjects; blood sampling once a day for 5 consecutive days) BV study, using Sysmex XN-module. Eight subjects were also scheduled to participate to both phases. The data were subject to outlier analysis prior to CV-ANOVA, to determine the BV estimates with the relative confidence intervals. The medium-term and short-term within-subject BV (CV I ) was comprised between 2.3 and 7.0% and 1.1-8.6%, whereas the medium-term and short-term between-subjects BV (CV G ) was comprised between 7.1 and 20.7% and 6.8-48.6%. The index of individuality and index of heterogeneity were always respectively 0.63 for all the parameters, in both arms of the study. The RCVs were similar for all parameters, in both arms of the study. This study allowed to define the BV estimates of many platelet parameters, some of them unavailable in literature. The kinetics of platelet turnover suggests the use of short-term BV data for calculating analytical goals and RCV. The correct clinical interpretation of platelet parameters also necessitates that each laboratory estimates local RCV values. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Platelet Function Analyzer 100 and Brain Natriuretic Peptide as Biomarkers in Obstructive Hypertrophic Cardiomyopathy.

    Science.gov (United States)

    Blackshear, Joseph L; Safford, Robert E; Thomas, Colleen S; Bos, J Martijn; Ackerman, Michael J; Geske, Jeffrey B; Ommen, Steve R; Shapiro, Brian P; Johns, Gretchen S

    2018-03-15

    To test dual blood biomarkers compared with electrocardiogram (ECG) for hypertrophic cardiomyopathy (HC) screening, we performed 3 analyses and cut-point assessments. First, we measured platelet function analyzer (PFA)-100 (n = 99) and normalized B-type natriuretic peptide (BNP) or NT-proBNP (BNP/upper limit of normal [ULN], n = 92) in 64 patients with HC and 29 normal controls (NCs). Second, from the regression equation between PFA and gradient (r = 0.77), we derived estimated PFA in a population of 189 patients with functional class I HC in whom measured BNP/ULN and ECG were available, and calculated single and dual biomarker sensitivity and specificity compared with ECG. Finally, we compared BNP/ULN in class I patients based on mutation and familial history status. In 42 patients with obstructive HC versus NCs, there was a slight overlap of PFA and BNP/ULN, but for the product of PFA × BNP/ULN, there was near-complete separation of values. Among patients with class I obstructive HC, estimated PFA × BNP/ULN had a sensitivity of 93% and a specificity of 100%; in latent and nonobstructive HC, sensitivity dropped to 61% and 72%; for ECG in obstructive, latent, and nonobstructive HC, sensitivity was 71%, 34%, and 67%. Functional class I patients with positive (n = 28) and negative (n = 36) sarcomere mutations and a positive (n = 71) or a negative (n = 109) family history had significant elevations of BNP/ULN versus NC, with no between-group differences. In conclusion, PFA and BNP were highly associated with obstructive HC and could potentially be used for screening; BNP was not uniquely elevated in patients with familial versus nonfamilial or mutation-positive versus mutation-negative HC. Copyright © 2017 Elsevier Inc. All rights reserved.

  12. Pre-experiment testing of the Multi Channel Systems 16-channel preamplifier CPA16

    International Nuclear Information System (INIS)

    Patin, J B; Stoyer, M A; Moody, K J; Friensehner, A V

    2003-01-01

    The 16-channel preamplifier model CPA16 from Multi Channel Systems was studied. The CPA16 preamplifier/amplifier module is a candidate to be used as the preamplifiers and amplifiers for the focal plane detectors of the Mass Analyzer of Super Heavy Atoms (MASHA). The equipment used to test the CPA16, the results of testing the CPA16 with a pulser, a mixed 229 Th/ 148 Gd source and a 252 Cf source, and a summary of the results will be presented

  13. CPA beats oo-CFA

    OpenAIRE

    Besson , Frédéric

    2009-01-01

    International audience; Context-sensitive points-to analysis is the current most scalable technology for constructing a precise control-flow graph for large object-oriented programs. One appealing feature of this framework is that it is parametric thus allowing to trade time for precision. Typical instances of this framework are k-CFAs and Agesen's Cartesian Product Algorithm (CPA). It is common sense that k-CFAs (for increasing ks) form a hierarchy. Yet, what is the relative precision of k-C...

  14. DMSO inhibits human platelet activation through cyclooxygenase-1 inhibition. A novel agent for drug eluting stents?

    International Nuclear Information System (INIS)

    Asmis, Lars; Tanner, Felix C.; Sudano, Isabella; Luescher, Thomas F.; Camici, Giovanni G.

    2010-01-01

    Background: DMSO is routinely infused together with hematopoietic cells in patients undergoing myeloablative therapy and was recently found to inhibit smooth muscle cells proliferation and arterial thrombus formation in the mouse by preventing tissue factor (TF), a key activator of the coagulation cascade. This study was designed to investigate whether DMSO prevents platelet activation and thus, whether it may represent an interesting agent to be used on drug eluting stents. Methods and results: Human venous blood from healthy volunteers was collected in citrated tubes and platelet activation was studied by cone and platelet analyzer (CPA) and rapid-platelet-function-assay (RPFA). CPA analysis showed that DMSO-treated platelets exhibit a lower adherence in response to shear stress (-15.54 ± 0.9427%, n = 5, P < 0.0001 versus control). Additionally, aggregometry studies revealed that DMSO-treated, arachidonate-stimulated platelets had an increased lag phase (18.0% ± 4.031, n = 9, P = 0.0004 versus control) as well as a decreased maximal aggregation (-6.388 ± 2.212%, n = 6, P = 0.0162 versus control). Inhibitory action of DMSO could be rescued by exogenous thromboxane A2 and was mediated, at least in part, by COX-1 inhibition. Conclusions: Clinically relevant concentrations of DMSO impair platelet activation by a thromboxane A2-dependent, COX-1-mediated effect. This finding may be crucial for the previously reported anti-thrombotic property displayed by DMSO. Our findings support a role for DMSO as a novel drug to prevent not only proliferation, but also thrombotic complications of drug eluting stents.

  15. CPA ups storage at Lavera site

    International Nuclear Information System (INIS)

    Back, R.

    1992-01-01

    Compagnie Parisienne des Asphaltes (CPA; Paris) and its subsidiary Pacsud -owned 65% by CPA and 35% by Shell Chimie (Paris) - have inaugurated their new chemicals storage site at Lavera, France, in the Europort South complex near Marseilles. The facilities, with 60,000-m.t./year capacity, also include a barreling plant that will have output of up to 250 bbl/hour when it comes onstream next spring. Total investment for these facilities amount to F122 million ($22.5 million), including F22 million for the barreling unit. CPA, France's number two storage specialist, after LB Chimie (Paris), is jointly owned by investment company Union Normandie (60%), Elf Aquitaine (Paris; 20%), and Total (Paris; 20%). Adding to its existing French storage sites at Dunkirk and Rouen, CPA says it decided to build on the Pacsud venture because it considered it attractive to invest in the petroleum and petrochemical complex of Fos-Berre-Lavera, particularly since the present trend in the oil and chemical industries is to subcontract all ancillary functions, especially logistics. CPA general manager Rafic Charles Rathle says that customer requirements and the role of the service provider are changing. With that in mid, CPA, in addition to providing storage terminals, converts its depots into distribution and packing centers. At Lavera the company has taken over storage, blending, and barreling operations for Pacsud and its direct customers. For example, Pacsud has a long-term contract with Shell Chimie for the latter's additive production at a 10,000-m.t./year rate. Another long-term contract is being negotiated, but the identity of the customer was not revealed

  16. Comprehension-Driven Program Analysis (CPA) for Malware Detection in Android Phones

    Science.gov (United States)

    2015-07-01

    Android source . 3.1.2.2 Analyzers An analyzer conforms to specifications defined by the Security Toolbox. Specifically an analyzer encapsulates a...COMPREHENSION-DRIVEN PROGRAM ANALYSIS (CPA) FOR MALWARE DETECTION IN ANDROID PHONES IOWA STATE UNIVERSITY JULY 2015 FINAL...average 1 hour per response, including the time for reviewing instructions, searching existing data sources , gathering and maintaining the data needed

  17. Dose- and time-related platelet response with apheresis platelet concentrates and pooled platelets

    Directory of Open Access Journals (Sweden)

    Mohammad Mizanur Rahman

    2017-02-01

    Full Text Available This study was carried out to compare the post-transfusion platelet increment between the apheresis platelet concentrate (n=74 and pooled platelets (n=54. Pre- and post-transfusion platelet count of the recipient were carried out by automated hematology analyzer. In apheresis platelet concentrate group, the mean 24 hours post-transfusion platelet increment was 47 x 109/L which was statistically significant (p<0.001. On the other hand, in pooled platelets group, the mean 24 hours post–transfusions platelet count increment was 11.0 x 109/L which was also statistically significant (p<0.001. This study concluded that the transfusion of apheresis platelet concentrate was more useful than the transfusion of pooled platelets in terms of platelet count increment and requirement of donor.

  18. Radiolabeled platelets

    International Nuclear Information System (INIS)

    Datz, F.L.; Taylor, A.T.

    1986-01-01

    Initial interest in developing techniques to radiolabel platelets was spurred by the lack of an accurate method for measuring platelet life span in both normals and in thrombocytopenic patients. Early investigators could obtain only rough estimates of platelet life spans by monitoring the platelet counts of thrombocytopenic patients undergoing platelet transfusions. Labels were also sought that would allow imaging of platelets in vivo in order to better understand the pathophysiology of atherosclerosis, thrombophlebitis, and clotting disorders, and to improve the clinical diagnosis of these diseases. Two types of platelet labels were investigated: cohort (pulse) labels and random labels. Cohort labels are taken up by megakaryocytes in the bone marrow and incorporated in the DNA and other components of the forming platelet. In theory, only freshly released platelets of a uniform age are labeled. Random labels, on the other hand, tag platelets in the peripheral blood, labeling platelets of all ages

  19. A Note of Caution: The International CPA Designation

    Science.gov (United States)

    Kerr, Stephen G.

    2011-01-01

    The National Association of State Boards of Accountancy (NASBA) is pursuing initiatives to make the U.S. Uniform CPA Examination more accessible to candidates outside of the United States. At the heart of their plan is a desire to ensure that the U.S.-CPA retains its position as a gold standard in the world of professional accountancy. Over the…

  20. Platelet function in dogs

    DEFF Research Database (Denmark)

    Nielsen, Line A.; Zois, Nora Elisabeth; Pedersen, Henrik D.

    2007-01-01

    Background: Clinical studies investigating platelet function in dogs have had conflicting results that may be caused by normal physiologic variation in platelet response to agonists. Objectives: The objective of this study was to investigate platelet function in clinically healthy dogs of 4...... different breeds by whole-blood aggregometry and with a point-of-care platelet function analyzer (PFA-100), and to evaluate the effect of acetylsalicylic acid (ASA) administration on the results from both methods. Methods: Forty-five clinically healthy dogs (12 Cavalier King Charles Spaniels [CKCS], 12...... applied. However, the importance of these breed differences remains to be investigated. The PFA-100 method with Col + Epi as agonists, and ADP-induced platelet aggregation appear to be sensitive to ASA in dogs....

  1. Reproducibility of Manual Platelet Estimation Following Automated Low Platelet Counts

    Directory of Open Access Journals (Sweden)

    Zainab S Al-Hosni

    2016-11-01

    Full Text Available Objectives: Manual platelet estimation is one of the methods used when automated platelet estimates are very low. However, the reproducibility of manual platelet estimation has not been adequately studied. We sought to assess the reproducibility of manual platelet estimation following automated low platelet counts and to evaluate the impact of the level of experience of the person counting on the reproducibility of manual platelet estimates. Methods: In this cross-sectional study, peripheral blood films of patients with platelet counts less than 100 × 109/L were retrieved and given to four raters to perform manual platelet estimation independently using a predefined method (average of platelet counts in 10 fields using 100× objective multiplied by 20. Data were analyzed using intraclass correlation coefficient (ICC as a method of reproducibility assessment. Results: The ICC across the four raters was 0.840, indicating excellent agreement. The median difference of the two most experienced raters was 0 (range: -64 to 78. The level of platelet estimate by the least-experienced rater predicted the disagreement (p = 0.037. When assessing the difference between pairs of raters, there was no significant difference in the ICC (p = 0.420. Conclusions: The agreement between different raters using manual platelet estimation was excellent. Further confirmation is necessary, with a prospective study using a gold standard method of platelet counts.

  2. Platelet mimicry

    DEFF Research Database (Denmark)

    Moghimi, Seyed Moein; Hunter, Alan Christy; Peer, Dan

    2016-01-01

    Here we critically examine whether coating of nanoparticles with platelet membranes can truly disguise them against recognition by elements of the innate immune system. We further assess whether the "cloaking technology" can sufficiently equip nanoparticles with platelet-mimicking functionalities...

  3. Using Critical Path Analysis (CPA) in Place Marketing process

    OpenAIRE

    Metaxas, Theodore; Deffner, Alex

    2013-01-01

    The article awards the use of CPA as a methodological tool in Place Marketing implementation. Taking into account that Place Marketing is a strategic process based on ‘project’ meaning with particular actions in specific time horizon, the article proposed that CPΑ has the capacity to satisfy this hypothesis. For this reason, the article creates a hypothetical scenario of CPA in four phases, planning, programming, implementation and feedback, taking as a case study the city of Rostock in Germa...

  4. Platelet count

    Science.gov (United States)

    The normal number of platelets in the blood is 150,000 to 400,000 platelets per microliter (mcL) or 150 to 400 × 10 9 /L. Normal value ranges may vary slightly. Some lab use different measurements or ...

  5. Modeling of phase equilibria with CPA using the homomorph approach

    DEFF Research Database (Denmark)

    Breil, Martin Peter; Tsivintzelis, Ioannis; Kontogeorgis, Georgios

    2011-01-01

    For association models, like CPA and SAFT, a classical approach is often used for estimating pure-compound and mixture parameters. According to this approach, the pure-compound parameters are estimated from vapor pressure and liquid density data. Then, the binary interaction parameters, kij, are ...

  6. 7 CFR 1773.5 - Qualifications of CPA.

    Science.gov (United States)

    2010-01-01

    ... the accounting and audit practice conducted by an approved peer review program under paragraph (c)(4... must undergo a peer review of the accounting and audit practice within 36 months of the issuance of the... AICPA; (C) Submit to peer reviews of the CPA's accounting and audit practice every 36 months or at such...

  7. The CPA Exam as a Postcurriculum Accreditation Assessment

    Science.gov (United States)

    Barilla, Anthony G.; Jackson, Robert E.; Mooney, J. Lowell

    2008-01-01

    Business schools often attain accreditation to demonstrate program efficacy. J. A. Marts, J. D. Baker, and J. M. Garris (1988) hypothesized that candidates from Association to Advance Collegiate Schools of Business International (AACSB)-accredited accounting programs perform better on the CPA exam than do candidates from non-AACSB-accredited…

  8. A CPA study of the phonon structure of disordered superlattices

    International Nuclear Information System (INIS)

    Shijie Xiong; Gendi Pang; Chienhua Tsai.

    1985-08-01

    The phonon structure of superlattices or modulated alloys with substitutional disorder is studied in the Coherent Phase Approximation (CPA). We consider first the case with diagonal disorder only, by adopting a virtual crystal approximation for the force constants. Then we treat the more complicated case with inclusion of off-diagonal disorder. Numerical examples are also studied in both cases. (author)

  9. Uncertainty analysis of the CPA and a quadrupolar CPA equation of state - With emphasis on CO2

    DEFF Research Database (Denmark)

    Bjørner, Martin G.; Sin, Gürkan; Kontogeorgis, Georgios M.

    2016-01-01

    The parameters of thermodynamic models, such as the cubic plus association (CPA) equation of state, are subject to uncertainties due to measurement errors in the experimental data that the models are correlated to. More importantly as the number of adjustable parameters increase, the parameter...

  10. Platelet Donation

    Science.gov (United States)

    ... During your donation you can relax, watch a movie, listen to music…in a few hours you’ ... requirements may become eligible to donate platelets. Please review our eligibility requirements as some states require parental ...

  11. Modeling derivative properties and binary mixtures with CO2 using the CPA and the quadrupolar CPA equations of state

    DEFF Research Database (Denmark)

    Bjørner, Martin Gamel; Kontogeorgis, Georgios

    2016-01-01

    The cubic plus association (CPA) equation of state (EoS) is extended to include quadrupolar interactions. The quadrupolar term is based on a modification of the perturbation terms by Larsen et al. (1977) [5] for a hard sphere fluid with a symmetric point quadrupole moment. The new quadrupolar CPA......CPA can accurately correlate both the phase behaviour of CO2+hydrocarbon mixtures as well as mixtures of CO2+a self-associating compound....

  12. Heterogeneity of rabbit platelets

    International Nuclear Information System (INIS)

    Karpatkin, S.

    1978-01-01

    Rabbits were injected intravenously with a cohort platelet label, 75 Se-selenomethionine. Platelet-rich plasma was separated into five different platelet density fractions on each of seven days by repetitively centrifuging the same sample of platelet-rich plasma at increasing gravitational force. The heaviest platelet sediment fraction was enriched with larger platelets. The lightest platelet sediment fraction was enriched with smaller platelets. Incorporation of isotope into the heaviest platelet fraction was considerably greater than incorporation into the lightest platelet fraction. The mean platelet survival of the lightest two fractions was significantly shorter than that of the heaviest three fractions. SDS-polyacrylamide gel electrophoresis of the platelet cell sap generally revealed 10 prominent protein bands for the heaviest platelet fractions. The lightest platelet fraction had six absent to markedly diminished platelet proteins. The data are compatible with two models, (1) heavy-large platelets are, on average, young platelets which become lighter-smaller platelets while losing platelet membranes and cell sap components with time. (2) Heavy-large platelets and light-small platelets are produced independently by specific megakarocytes. The heavy-large platelets incorporate more isotope that lighter-smaller platelets (possibly because of their megakarocyte precursor). However, they are released earlier into the circulation than lighter-smaller platelets and are therefore younger platelets. The light-smaller platelets which are released later into the circulation have a shorter survival. (author)

  13. Platelet Function Tests

    Science.gov (United States)

    ... Patient Resources For Health Professionals Subscribe Search Platelet Function Tests Send Us Your Feedback Choose Topic At ... Also Known As Platelet Aggregation Studies PFT Platelet Function Assay PFA Formal Name Platelet Function Tests This ...

  14. Platelet antibodies blood test

    Science.gov (United States)

    This blood test shows if you have antibodies against platelets in your blood. Platelets are a part of the blood ... Chernecky CC, Berger BJ. Platelet antibody - blood. In: Chernecky ... caused by platelet destruction, hypersplenism, or hemodilution. ...

  15. 100 TW CPA Nd: Glass laser for fast ignition research

    International Nuclear Information System (INIS)

    Fujita, H.; Daido, H.; Jitsuno, T.

    2001-01-01

    A 100 TW chirped pulse amplification (CPA) Nd:glass laser has been developed to investigate the fast ignition concept. The ultrashort-pulse (60 TW, 42 J, 0.7 ps) was focused on plane targets, plane targets with preformed plasma, and high density compressed plasmas produced by the GEKKO-XII (12 beam, 20 kJ) laser. Focus intensity of >10 19 W/cm 2 has been achieved. (author)

  16. Platelet Donation

    Science.gov (United States)

    ... time’ to unwind from the daily stresses of life while helping save lives. What are the benefits to donating platelets? Knowing you’re helping cancer ... of your arm. That pinch is similar to what you will feel when the needle is ... compared to a traditional whole blood donation so some donors find it to ...

  17. Comparison of point-of-care methods for preparation of platelet concentrate (platelet-rich plasma).

    Science.gov (United States)

    Weibrich, Gernot; Kleis, Wilfried K G; Streckbein, Philipp; Moergel, Maximilian; Hitzler, Walter E; Hafner, Gerd

    2012-01-01

    This study analyzed the concentrations of platelets and growth factors in platelet-rich plasma (PRP), which are likely to depend on the method used for its production. The cellular composition and growth factor content of platelet concentrates (platelet-rich plasma) produced by six different procedures were quantitatively analyzed and compared. Platelet and leukocyte counts were determined on an automatic cell counter, and analysis of growth factors was performed using enzyme-linked immunosorbent assay. The principal differences between the analyzed PRP production methods (blood bank method of intermittent flow centrifuge system/platelet apheresis and by the five point-of-care methods) and the resulting platelet concentrates were evaluated with regard to resulting platelet, leukocyte, and growth factor levels. The platelet counts in both whole blood and PRP were generally higher in women than in men; no differences were observed with regard to age. Statistical analysis of platelet-derived growth factor AB (PDGF-AB) and transforming growth factor β1 (TGF-β1) showed no differences with regard to age or gender. Platelet counts and TGF-β1 concentration correlated closely, as did platelet counts and PDGF-AB levels. There were only rare correlations between leukocyte counts and PDGF-AB levels, but comparison of leukocyte counts and PDGF-AB levels demonstrated certain parallel tendencies. TGF-β1 levels derive in substantial part from platelets and emphasize the role of leukocytes, in addition to that of platelets, as a source of growth factors in PRP. All methods of producing PRP showed high variability in platelet counts and growth factor levels. The highest growth factor levels were found in the PRP prepared using the Platelet Concentrate Collection System manufactured by Biomet 3i.

  18. Hybridization effect on generation capability of an embedded CPA

    Directory of Open Access Journals (Sweden)

    M. Klach

    2016-03-01

    Full Text Available The purpose of this paper is to compare performances of two configurations of an embedded Claw Pole Alternator (CPA where the excitation winding is transferred to the stator side. These configurations are: the Simple Excited Automotive Alternator (SE2A and the Hybrid Excited Automotive Alternator (HE2A. Performed study is based on test at no-load and under load operation regimes, using Magnetic Equivalent Circuit (MEC models validated experimentally. It has been found that the hybrid Excited claw pole alternator provides higher performances, due to the increase of leakage flux through the integration of permanent magnets between adjacent rotor claws.

  19. Inhibition of platelet aggregation by tartrazine and a pyrazolone analogue in normal and allergic individuals.

    Science.gov (United States)

    Gallagher, J S; Splansky, G L; Bernstein, I L

    1980-11-01

    The effect of tartrazine (T) (yellow dye No. 5) and one of its metabolites an aminopyrazolone analogue (1-sulphophenyl-3-carboxy-5-hydroxypyrazole, SCHP) upon collagen-induced platelet aggregation (C-PA) was investigated in fourteen atopic patients and fourteen normal subjects. Both T and SCHP inhibited C-PA in atopic patients at significantly lower doses than in normal volunteers. The mean inhibitory concentrations of SCHP were similar to aspirin in both atopic and normal individuals. Although the precise mechanism by which these chemicals block C-PA has not been elucidated, this in vitro system may be a useful method of assessing non-immune mechanisms involved in reactions to tartrazine.

  20. Congenital platelet function defects

    Science.gov (United States)

    ... pool disorder; Glanzmann's thrombasthenia; Bernard-Soulier syndrome; Platelet function defects - congenital ... Congenital platelet function defects are bleeding disorders that cause reduced platelet function. Most of the time, people with these disorders have ...

  1. Blood platelet kinetics and platelet transfusion.

    Science.gov (United States)

    Aster, Richard H

    2013-11-01

    The discovery of citrate anticoagulant in the 1920s and the development of plastic packs for blood collection in the 1960s laid the groundwork for platelet transfusion therapy on a scale not previously possible. A major limitation, however, was the finding that platelet concentrates prepared from blood anticoagulated with citrate were unsuitable for transfusion because of platelet clumping. We found that this could be prevented by simply reducing the pH of platelet-rich plasma to about 6.5 prior to centrifugation. We used this approach to characterize platelet kinetics and sites of platelet sequestration in normal and pathologic states and to define the influence of variables such as anticoagulant and ABO incompatibility on post-transfusion platelet recovery. The "acidification" approach enabled much wider use of platelet transfusion therapy until alternative means of producing concentrates suitable for transfusion became available.

  2. Application of the CPA equation of state to glycol/hydrocarbons liquid-liquid equilibria

    DEFF Research Database (Denmark)

    Derawi, Samer; Michelsen, Michael Locht; Kontogeorgis, Georgios

    2003-01-01

    The Cubic Plus Association (CPA) equation of state is a thermodynamic model, which combines the well-known cubic SRK (Soave-Redlich-Kwong) equation of state and the association term proposed by Wertheim, typically employed in models like SAFT (statistical associating fluid theory). CPA has been...

  3. Automated simultaneous assembly of multi-stage testing for the uniform CPA examination

    NARCIS (Netherlands)

    Breithaupt, Krista; Ariel, A.; Veldkamp, Bernard P.

    2004-01-01

    Some solutions used in the assembly of the computerized Uniform Certified Public Accountancy (CPA) licensing examination are offered as practical alternatives for operational programs producing large numbers of forms. The Uniform CPA examination will be offered as an adaptive multi-stage test (MST)

  4. The 150 Credit-Hour Requirement and CPA Examination Pass Rates--A Four Year Study

    Science.gov (United States)

    Briggs, Gary P.; He, Lerong

    2012-01-01

    Debate concerning the minimum educational requirements of certified public accountant (CPA) candidates in the USA has been taking place for decades. This paper compares the sectional pass rates of CPA candidates from jurisdictions requiring 150 credit hours of college study with the pass rates of candidates from jurisdictions not requiring 150…

  5. THE CPA QUALIFICATION METHOD BASED ON THE GAUSSIAN CURVE FITTING

    Directory of Open Access Journals (Sweden)

    M.T. Adithia

    2015-01-01

    Full Text Available The Correlation Power Analysis (CPA attack is an attack on cryptographic devices, especially smart cards. The results of the attack are correlation traces. Based on the correlation traces, an evaluation is done to observe whether significant peaks appear in the traces or not. The evaluation is done manually, by experts. If significant peaks appear then the smart card is not considered secure since it is assumed that the secret key is revealed. We develop a method that objectively detects peaks and decides which peak is significant. We conclude that using the Gaussian curve fitting method, the subjective qualification of the peak significance can be objectified. Thus, better decisions can be taken by security experts. We also conclude that the Gaussian curve fitting method is able to show the influence of peak sizes, especially the width and height, to a significance of a particular peak.

  6. Platelet production, clearance and distribution in patients with idiopathic thrombocytopenic purpura

    International Nuclear Information System (INIS)

    Isaka, Yoshinari; Kambayashi, Junichi; Kimura, Kazufumi

    1990-01-01

    We have studied 8 normal subjects, and 12 patients with idiopathic thrombocytopenic purpura whose platelet counts ranged from 9x10 9 /L to 40x10 9 /L. Autologous platelets labeled with 111 In-tropolone were used for evaluation of mean platelet survival, platelet turnover, platelet sequestration sites, and platelet production (turnover) to clearance (sum of platelet uptake in the liver and the spleen) ratio. Platelet survival correlated directly with platelet counts. There was no significant correlation between the platelet sequestration pattern and platelet count, survival, or turnover. Sum of platelet uptake in the liver and the spleen showed a significant inverse correlation with platelet survival. No significant correlation was found between platelet turnover and platelet count. There was a significant correlation between the platelet production and clearance index when all subjects were analyzed. The distribution of platelet turnover showed considerable individual variation; eight of twelve patients showed platelet turnover less than mean minus 2SD of the control value, but others showed normal range. We conclude that although platelet destruction mechanism in RES shows a primary role of thrombocytopenia, impaired rate of effective thrombopoiesis may also contribute to disease severity in ITP. (author)

  7. Flow cytometric analysis of platelet cyclooxygenase-1 and -2 and surface glycoproteins in patients with immune thrombocytopenia and healthy individuals.

    Science.gov (United States)

    Rubak, Peter; Kristensen, Steen D; Hvas, Anne-Mette

    2017-06-01

    Immature platelets may contain more platelet enzymes such as cyclooxygenase (COX)-1 and COX-2 than mature platelets. Patients with immune thrombocytopenia (ITP) have a higher fraction of immature platelets and can therefore be utilized as a biological model for investigating COX-1 and COX-2 platelet expression. The aims were to develop flow cytometric assays for platelet COX-1 and COX-2 and to investigate the COX-1 and COX-2 platelet expression, platelet turnover, and platelet glycoproteins in ITP patients (n = 10) compared with healthy individuals (n = 30). Platelet count and platelet turnover parameters (mean platelet volume (MPV), immature platelet fraction (IPF), and immature platelet count (IPC)) were measured by flow cytometry (Sysmex XE-5000). Platelet COX-1, COX-2, and the glycoproteins (GP)IIb, IX, Ib, Ia, and IIIa were all analyzed by flow cytometry (Navios) and expressed as median fluorescence intensity. COX analyses were performed in both whole blood and platelet rich plasma (PRP), whereas platelet glycoproteins were analyzed in whole blood only. ITP patients had significantly lower platelet count (55 × 10 9 /L) than healthy individuals (240 × 10 9 /L, p platelet count and IPC (both p-values Platelet COX-1 expression was higher in ITP patients than healthy individuals using whole blood (p COX-1 platelet turnover and COX-1 expression (all p-values platelet turnover and COX-1 and COX-2 expressions (all p-values platelet turnover in ITP patients (all p-values 0.14, rho = 0.11-0.28). In conclusion, ITP patients expressed higher COX-1 and platelet glycoprotein levels than healthy individuals. COX-1 and platelet glycoproteins demonstrated positive correlations with platelet turnover in ITP patients. In healthy individuals, COX-1 and COX-2 expression correlated positively with platelet turnover. PRP was more sensitive compared with whole blood as regards determination of COX. Therefore, PRP is the recommended matrix for investigating COX-1 and COX-2 in

  8. Endospore production allows using spray-drying as a possible formulation system of the biocontrol agent Bacillus subtilis CPA-8.

    Science.gov (United States)

    Yánez-Mendizabal, V; Viñas, I; Usall, J; Cañamás, T; Teixidó, N

    2012-04-01

    The role of endospore production by Bacillus subtilis CPA-8 on survival during spray-drying was investigated by comparison with a non-spore-forming biocontrol agent Pantoea agglomerans CPA-2. Endospore formation promoted heat resistance in CPA-8 depending on growth time (72 h cultures were more resistant than 24 h ones). The survival of CPA-8 and CPA-2 after spray-drying was determined after being grown in optimised media for 24 and 72 h. Spray-dried 72 h CPA-8 had the best survival (32%), while CPA-2 viability was less than 2%. CPA-8 survival directly related with its ability to produce endospores. Spray-dried CPA-8 reduced Monilinia fructicola conidia germination similarly to fresh cells, demonstrating that spray-drying did not adversely affect biocontrol efficacy. Endospore production thus improves CPA-8 resistance to spray-drying. These results can provide a reliable basis for optimising of the spray-drying formulation process for CPA-8 and other microorganisms.

  9. Assessment of ASTEC-CPA pool scrubbing models against POSEIDON-II and SGTR-ARTIST data

    International Nuclear Information System (INIS)

    Herranz, Luis E.; Fontanet, Joan

    2009-01-01

    Aerosol scrubbing in pools mitigates the potential source term in key severe accident scenarios in PWRs and BWRs. Even though models were extensively validated in the past, a thorough and systematic validation under key challenging conditions is missing. Some of those conditions are high injection velocity, high pool temperature and/or presence of submerged structures. In particular, in-code models have been neither updated nor validated based on the most recent experimental data. The POSEIDON-II and the SGTR-ARTIST projects produced sets of data under conditions of utmost interest for pool scrubbing validation: high temperature and submerged structures. This paper investigates the response of models encapsulated in the CPA module of the ASTEC code in the simulation of those experimental set-ups. The influence of key pool scrubbing variables like steam fraction, water depth, gas flow-rate and particle size has been analyzed. Additionally, comparisons to stand-alone code (i.e., SPARC90) responses have also been obtained, so that prediction-to-data deviations can be discussed and attributed to either model grounds and/or model implementation in integral accident codes. This work has demonstrated that ASTEC-CPA limitations to capture fundamental trends of aerosol pool scrubbing are substantial (although the SGTR scenarios should not be properly considered within the CPA scope) and they stem from both original models (i.e., SPARC90) and model implementation. This work has been carried out within the European SARNET project of the VI Framework Program of EURATOM. (author)

  10. Comparative evaluation of platelet count and antimicrobial efficacy of injectable platelet-rich fibrin with other platelet concentrates: An in vitro study

    Directory of Open Access Journals (Sweden)

    Prerna Ashok Karde

    2017-01-01

    Full Text Available Background: Platelet concentrates are used in various medical procedures to promote soft- and hard-tissue regeneration. In recent times, their antimicrobial efficacy is also explored. However, various platelet concentrates have evolved which differ in the centrifugation protocols. One such recently introduced platelet concentrate is injectable platelet-rich fibrin (i-PRF concentrate. Hence, the aim was to evaluate the antimicrobial property, and platelet count of i-PRF in comparison to other platelet concentrates, i.e., PRF, platelet-rich plasma (PRP, and control (whole blood. Materials and Methods: Blood samples were obtained from 10 chronic generalized marginal gingivitis patients. Platelet concentrates were prepared using standardized centrifugation protocol. Platelet count was evaluated by manual counting method using smear preparation of each sample. Subsequently, antimicrobial activity against oral bacteria was examined on blood agar using disc diffusion method to quantify the inhibitory effects. Results: Statistical significance was analyzed by one-way analysis of variance (ANOVA. P 0.05. i-PRF showed statistically significant difference (P < 0.001 in platelet count when compared to control. It was also significant when compared to PRP (P < 0.01, PRF (P < 0.001. Conclusion: i-PRF has maximum antimicrobial efficacy and higher platelet count in comparison to other platelet concentrates, thereby indicating to have a better regenerative potential then others.

  11. In vitro effect of sodium nitrite on platelet aggregation in human platelet rich plasma--preliminary report.

    Science.gov (United States)

    Kadan, M; Doğanci, S; Yildirim, V; Özgür, G; Erol, G; Karabacak, K; Avcu, F

    2015-10-01

    The role of nitrates and nitric oxide on platelet functions has obtained an increasing attention with respect to their potential effects on cardiovascular disorders. In this study we aimed to analyze the effect of sodium nitrite on platelet functions in human platelets. This in vitro study was designed to show the effect of sodium nitrite on platelet functions in seven healthy volunteers. Blood samples were centrifuged to prepare platelet rich plasma and platelet poor plasma. Platelet rich plasma was diluted with the platelet poor plasma to have a final count of 300,000 ± 25,000 platelets. Platelet rich plasma was incubated with six different increasing doses (from 10 μM to 5 mM) of sodium nitrite for 1 hour at 37°C. Then stimulating agents including collagen (3 μg ml-1), adenosine diphosphate (10 μM), and epinephrine (10 μM) were added to the cuvette. Changes in light transmission were observed for 10 minutes. In addition spontaneous aggregation were performed in control group with all aggregating agents separately. Effect of sodium nitrite on agonist-induced platelet aggregation depends on the concentration of sodium nitrite. Compared with control group, agonist-induced platelet aggregations were significantly suppressed by sodium nitrite at the concentration of 5, 1.0 and 0.5 mM. Our results suggested that sodium nitrite has inhibitory effects in vitro on platelet aggregation in a dose-dependent manner.

  12. Blood platelet kinetics and platelet transfusion

    OpenAIRE

    Aster, Richard H.

    2013-01-01

    The discovery of citrate anticoagulant in the 1920s and the development of plastic packs for blood collection in the 1960s laid the groundwork for platelet transfusion therapy on a scale not previously possible. A major limitation, however, was the finding that platelet concentrates prepared from blood anticoagulated with citrate were unsuitable for transfusion because of platelet clumping. We found that this could be prevented by simply reducing the pH of platelet-rich plasma to about 6.5 pr...

  13. Isolation and sequence analysis of pCS36-4CPA, a small plasmid from Citrobacter sp. 36-4CPA.

    Science.gov (United States)

    Zharikova, Natalia V; Iasakov, Timur R; Bumazhkin, Boris K; Patutina, Ekaterina O; Zhurenko, Evgeniia I; Korobov, Vladislav V; Sagitova, Alina I; Kuznetsov, Boris B; Markusheva, Tatiana V

    2018-05-01

    A small plasmid designated pCS36-4CPA with a size of 5217 base pairs and G-C content of 50.74% was isolated from Citrobacter sp. 36-4CPA. The origin of replication ( ori ) of the plasmid was identified as a region of about 800 bp in length with an identity of 67.1% to the ColE1 plasmid at the nucleotide level. The replication region contained typical elements of ColE1-like plasmids: RNA I and RNA II with their corresponding -10 and -35 boxes, a single-strand initiation site ( ssi ), and a lagging-strand termination site ( terH ). As seen in other ColE1-like plasmids, pCS36-4CPA carried mobilisation machinery that include mobABCD genes but it did not possess the rom gene. Analysis of the multimer resolution site ( mrs ) was performed and XerC and XerD binding sites were identified. Also, the 70-nt transcript Rcd of pCS36-4CPA was predicted and similarity of the transcript's secondary structure with those of the ColE1-family was shown. The cargo module of pCS36-4CPA contained three open reading frames (ORFs). Two of them (ORF5 and ORF6) showed no significant homology to any known gene sequences but contained putative THAP DNA-binding (DBD) and type II restriction endonuclease Eco O109I domains. The seventh open reading frame (ORF7) encodes YhdJ-like DNA modification methylase. The region highly homologous to pCS36-4CPA was found in the Salmonella phage SE2 genome.

  14. Fast numerical solution of KKR-CPA equations: Testing new algorithms

    Energy Technology Data Exchange (ETDEWEB)

    Bruno, E.; Florio, G.M.; Ginatempo, B.; Giuliano, E.S. (Universita di Messina (Italy))

    1994-04-01

    Some numerical methods for the solution of KKR-CPA equations are discussed and tested. New, efficient, computational algorithms are proposed, allowing a remarkable reduction of computing time and a good reliability in evaluating spectral quantities. 16 refs., 7 figs.

  15. Development of an Electrolyte CPA Equation of state for Applications in the Petroleum and Chemical Industries

    DEFF Research Database (Denmark)

    Maribo-Mogensen, Bjørn

    to the CPA EoS in the absence of electrolytes, making it possible to extend the applicability of the CPA EoS while retaining backwards compatibility and resuing the parameters for non-electrolyte systems . There are many challenges related to thermodynamic modeling of mixtures containing electrolytes......This thesis extends the Cubic Plus Association (CPA) equation of state (EoS) to handle mixtures containing ions from fully dissociated salts. The CPA EoS has during the past 18 years been applied to thermodynamic modeling of a wide range of industrially important chemicals, mainly in relation...... rarely been applied to all types of thermodynamic equilibrium calculations relevant to electrolyte solutions. This project has aimed to determine the best recipe to deliver a complete thermodynamic model capable of handling electrolytes in mixed solvents and at a wide range of temperature and pressure...

  16. Assessment of platelet function in healthy sedated cats using three whole blood platelet function tests.

    Science.gov (United States)

    Ho, Kimberly K; Abrams-Ogg, Anthony C G; Wood, R Darren; O'Sullivan, M Lynne; Kirby, Gordon M; Blois, Shauna L

    2015-05-01

    The objectives of this study were to establish feline references intervals for 3 commercial whole blood platelet function test analyzer systems: Multiplate analyzer (MP; Roche Diagnostics International Ltd., Rotkreuz, Switzerland), Platelet Function Analyzer-100 (PF: Siemens Canada, Mississauga, Ontario, Canada), and Plateletworks Combo-25 kit (PW; Helena Laboratories, Beaumont, TX). Venipuncture was performed on 55 healthy sedated cats, and platelet aggregation in response to adenosine diphosphate (ADP), collagen (COL), and arachidonic acid (AA; MP only) was assessed using citrated blood. For the MP analyzer, median (95% confidence intervals [CIs]) area under curve (Units) for ADP, COL, and AA agonists were 87 (11-176), 81 (32-129), and 91 (59-129), respectively. For the PF analyzer, median (95% CIs) closure time, using COL-ADP cartridges, was 69 (46-89) sec. For the PW assay, median (95% CIs) percent aggregations for ADP and COL agonists were 71 (18-92) and 49 (9-96), respectively, using impedance hematology analyzer platelet counts, and 94 (25-98) and 68 (14-119), respectively, using flow cytometry hematology analyzer platelet counts. There were low correlations between the PF analyzer (COL-ADP cartridge) and MP analyzer (COL agonist; ρ = 0.11), and between the PF analyzer (COL-ADP cartridge) and PW assay (COL agonist using impedance platelet counts; ρ = 0.14). The PW assay percent aggregations using impedance and flow cytometric platelet counts were correlated for both ADP (ρ = 0.64) and COL (ρ = 0.64) agonists. Platelet function testing using these tests are feasible in cats, but 95% CIs are wide, so single results may be difficult to interpret. Platelet counting by impedance or flow cytometry may be used for the PW assay but are not interchangeable. © 2015 The Author(s).

  17. A methodology for automated CPA extraction using liver biopsy image analysis and machine learning techniques.

    Science.gov (United States)

    Tsipouras, Markos G; Giannakeas, Nikolaos; Tzallas, Alexandros T; Tsianou, Zoe E; Manousou, Pinelopi; Hall, Andrew; Tsoulos, Ioannis; Tsianos, Epameinondas

    2017-03-01

    Collagen proportional area (CPA) extraction in liver biopsy images provides the degree of fibrosis expansion in liver tissue, which is the most characteristic histological alteration in hepatitis C virus (HCV). Assessment of the fibrotic tissue is currently based on semiquantitative staging scores such as Ishak and Metavir. Since its introduction as a fibrotic tissue assessment technique, CPA calculation based on image analysis techniques has proven to be more accurate than semiquantitative scores. However, CPA has yet to reach everyday clinical practice, since the lack of standardized and robust methods for computerized image analysis for CPA assessment have proven to be a major limitation. The current work introduces a three-stage fully automated methodology for CPA extraction based on machine learning techniques. Specifically, clustering algorithms have been employed for background-tissue separation, as well as for fibrosis detection in liver tissue regions, in the first and the third stage of the methodology, respectively. Due to the existence of several types of tissue regions in the image (such as blood clots, muscle tissue, structural collagen, etc.), classification algorithms have been employed to identify liver tissue regions and exclude all other non-liver tissue regions from CPA computation. For the evaluation of the methodology, 79 liver biopsy images have been employed, obtaining 1.31% mean absolute CPA error, with 0.923 concordance correlation coefficient. The proposed methodology is designed to (i) avoid manual threshold-based and region selection processes, widely used in similar approaches presented in the literature, and (ii) minimize CPA calculation time. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  18. Hypothermia and Platelet Dysfunction

    National Research Council Canada - National Science Library

    Michelson, Alan

    1993-01-01

    ... (the OPlib-Illa complex).3 Circulating platelets are normally in a resting state and, despite the presence of platelet surface GPTh-IX and OPlib-Illa complexes, they bind neither plasma von Willebrand factor nor plasma fibrinogen...

  19. Hypothermia and Platelet Dysfunction

    National Research Council Canada - National Science Library

    Michelson, A

    1994-01-01

    ... (the GPIIb-IIIa complex). Circulating platelets are normally in a resting state and, despite the presence of platelet surface GPIb-IX and GPIIb-IIIa complexes, they bind neither plasma von Willebrand factor nor plasma fibrinogen...

  20. Platelet cyclooxygenase expression in normal dogs.

    Science.gov (United States)

    Thomason, J; Lunsford, K; Mullins, K; Stokes, J; Pinchuk, L; Wills, R; McLaughlin, R; Langston, C; Pruett, S; Mackin, A

    2011-01-01

    Human platelets express both cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2). Variation in COX-2 expression could be a mechanism for variable response to aspirin. The hypotheses were that circulating canine platelets express COX-1 and COX-2, and that aspirin alters COX expression. The objective was to identify changes in platelet COX expression and in platelet function caused by aspirin administration to dogs. Eight female, intact hounds. A single population, repeated measures design was used to evaluate platelet COX-1 and COX-2 expression by flow cytometry before and after aspirin (10 mg/kg Q12h for 10 days). Platelet function was analyzed via PFA-100(®) (collagen/epinephrine), and urine 11-dehydro-thromboxane B(2) (11-dTXB(2)) was measured and normalized to urinary creatinine. Differences in COX expression, PFA-100(®) closure times, and urine 11-dTXB(2 ): creatinine ratio were analyzed before and after aspirin administration. Both COX-1 and COX-2 were expressed in canine platelets. COX-1 mean fluorescent intensity (MFI) increased in all dogs, by 250% (range 63-476%), while COX-2 expression did not change significantly (P = 0.124) after aspirin exposure, with large interindividual variation. PFA-100(®) closure times were prolonged and urine 11-dTXB(2) concentration decreased in all dogs after aspirin administration. Canine platelets express both COX isoforms. After aspirin exposure, COX-1 expression increased despite impairment of platelet function, while COX-2 expression varied markedly among dogs. Variability in platelet COX-2 expression should be explored as a potential mechanism for, or marker of, variable aspirin responsiveness. Copyright © 2011 by the American College of Veterinary Internal Medicine.

  1. Platelet Count and Plateletcrit

    African Journals Online (AJOL)

    strated that neonates with late onset sepsis (bacteremia after 3 days of age) had a dramatic increase in MPV and. PDW18. We hypothesize that as the MPV and PDW increase and platelet count and PCT decrease in sick children, intui- tively, the ratio of MPV to PCT; MPV to Platelet count,. PDW to PCT, PDW to platelet ...

  2. Circular polarization analyzer with polarization tunable focusing of surface plasmon polaritons

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Sen; Zhang, Yan, E-mail: yzhang@mail.cnu.edu.cn [Department of Physics, Harbin Institute of Technology, Harbin 150001 (China); Beijing Key Laboratory for Metamaterials and Devices, and Key Laboratory of Terahertz Optoelectronics, Ministry of Education, Department of Physics, Capital Normal University, Beijing 100048 (China); Wang, Xinke [Beijing Key Laboratory for Metamaterials and Devices, and Key Laboratory of Terahertz Optoelectronics, Ministry of Education, Department of Physics, Capital Normal University, Beijing 100048 (China); Kan, Qiang [State Key Laboratory for Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083 (China); Qu, Shiliang [Optoelectronics Department, Harbin Institute of Technology at Weihai, Weihai 264209 (China)

    2015-12-14

    A practical circular polarization analyzer (CPA) that can selectively focus surface plasmon polaritons (SPPs) at two separate locations, according to the helicity of the circularly polarized light, is designed and experimentally verified in the terahertz frequency range. The CPA consists of fishbone-slit units and is designed using the simulated annealing algorithm. By differentially detecting the intensities of the two SPPs focuses, the helicity of the incident circularly polarized light can be obtained and the CPA is less vulnerable to the noise of incident light. The proposed device may also have wide potential applications in chiral SPPs photonics and the analysis of chiral molecules in biology.

  3. Nattokinase improves blood flow by inhibiting platelet aggregation and thrombus formation

    OpenAIRE

    Jang, Ja-Young; Kim, Tae-Su; Cai, Jingmei; Kim, Jihyun; Kim, Youngeun; Shin, Kyungha; Kim, Kwang Sei; Park, Sung Kyeong; Lee, Sung-Pyo; Choi, Ehn-Kyoung; Rhee, Man Hee; Kim, Yun-Bae

    2013-01-01

    The effects of nattokinase on the in vitro platelet aggregation and in vivo thrombosis were investigated in comparison with aspirin. Rabbit platelet-rich plasma was incubated with nattokinase and aggregation inducers collagen and thrombin, and the platelet aggregation rate was analyzed. Nattokinase significantly inhibited both the collagen- and thrombin-induced platelet aggregations. Nattokinase also reduced thromboxane B2 formation from collagen-activated platelets in a concentration-depende...

  4. Effects of Platelets on Platelet Concentrate Product on the Activation of Human Peripheral Blood Monocyte Cells

    Directory of Open Access Journals (Sweden)

    N Sadat Razavi Hoseini

    2016-02-01

    Full Text Available Introduction: Monocytes can interact with platelets due to their surface molecules such as P-selectin glycoprotein ligand-1 (PSGL-1, and form monocyte-platelet complex. In the present study, the effects of platelets interaction of platelet concentrates (PCs and peripheral blood monocytes were investigated in vitro as a model to predict the probable interactions of these cells and consequently activation of monocytes. Methods: In this experimental study, units of whole blood and PCs were prepared from Tehran Blood Transfusion Center. After isolation of monocytes from the whole blood, these cells were treated with PC- derived platelets. The activation of monocytes was assessed before and after treatment by the analysis of the respiratory burst of monocytes using dihydrorhodamine 123 (DHR-123. The study data were analyzed using the non-parametric test of Wilcoxon. Results: The purity of monocytes was determined as 86.1±2 using NycoPrep method. The respiratory burst of monocytes was increased after exposure with platelets. In fact, the difference was significant when platelets were used on the 5th day of storage (P=0.001. Conclusions: The study findings revealed that platelets have an efficient capacity to stimulate and activate monocytes. The possible involvement of molecules in the interaction of platelet-monocyte demand to be further studied in future.

  5. Extended shelf life of random donor platelets stored for 7 days in platelet additive solution at different temperatures

    Directory of Open Access Journals (Sweden)

    Tulika Chandra

    2014-08-01

    Full Text Available Background: Platelets are routinely stored in plasma for 5 days at an average temperature of 22°C. In the present study, the shelf life of random donor platelets was extended by storing for 7 days with and without additive solution at temperatures of 22°C, 18°C, and 16°C. Methods: Random donor platelets were stored in 100% plasma and 20%/80% platelet additive solution. The data were compared using paired "t"- test. The confidence limit was kept at 95%, hence a "p" < 0.05 was considered to be statistically significant. Results: Out of total 150 samples, 148 samples were analyzed and 2 were discarded due to the bacterial contamination on day 7 at 22°C without platelet additive solution. A significant difference in platelet count, platelet factor 3 (PF 3, glucose, lactate dehydrogenase (LDH, and platelet aggregation was observed on day 7 (p < 0.001 at 16°C in without platelet additive solution. In platelet additive solution, the mean values of platelet count, platelet distribution width (PDW, LDH, and pH showed no significant difference on day 7 at 22°C, 18°C, and 16°C. Only significant differences were observed in the levels of mean platelet volume (MPV, PF 3, glucose, and platelet aggregation on day 7 (p < 0.001 at 16°C of the storage period. Conclusion: Random donor platelets functions are better maintained in platelet additive solution as compared to plasma at a lower temperature of 18°C but not at 16°C, on the 7 th day.

  6. Study on platelet kinetics

    International Nuclear Information System (INIS)

    Yui, Tokuo

    1981-01-01

    Fundamental study: Factors influencing the labeling on human platelets were evaluated and optimal labeling conditions were chosen. Then, platelet survival times were measured and organ distribution of labeled platelets was observed in rat by four different methods. These results were compared with each other. Based on the findings of those studies, the protocol of human platelet labeling with 111 In-oxine for clinical use was established. Clinical study: In normal cases, a platelet survival time and a platelet turnover rate were quite similar to the results from 51 Cr method. In gamma camera imaging, a radioactivity on the heart decreased with the lapse of time, while that on the spleen and liver gradually increased. In patients with idiopathic thrombocytopenic purpura, platelet survival time was markedly shortened and both a platelet turnover rate and an effective production increased. In patient with congestive splenomegaly, a platelet survival time was normal, whereas a platelet pooling on the spleen markedly increased. In patients who were implanted dacron-graft for abdominal aortic aneurysm, a radioactivity accumulated to the graft and a platelet survival time shortened. In a patient with myocardial infarction, the camera imaging clearly showed the thrombus in the left ventricular aneurysm. In three patients with mitral stenosis, thrombi in left atrium were observed at the camera images. Imaging of a platelet distribution and measurement of platelet survival time using 111 In-oxine labeled platelets are considered to be an excellent method for the diagnosis and decision of treatment on various disorders with thrombocytopenia and thrombosis. (J.P.N.)

  7. Simulation of experiment on aerosol behaviour at severe accident conditions in the LACE experimental facility with the ASTEC CPA code

    International Nuclear Information System (INIS)

    Kljenak, I.; Mavko, B.

    2007-01-01

    The experiment LACE LA4 on thermal-hydraulics and aerosol behavior in a nuclear power plant containment, which was performed in the LACE experimental facility, was simulated with the ASTEC CPA module of the severe accident computer code ASTEC V1.2. The specific purpose of the work was to assess the capability of the module (code) to simulate thermal-hydraulic conditions and aerosol behavior in the containment of a light-water-reactor nuclear power plant at severe accident conditions. The test was simulated with boundary conditions, described in the experiment report. Results of thermal-hydraulic conditions in the test vessel, as well as dry aerosol concentrations in the test vessel atmosphere, are compared to experimental results and analyzed. (author)

  8. Formulation development of the biocontrol agent Bacillus subtilis strain CPA-8 by spray-drying.

    Science.gov (United States)

    Yánez-Mendizábal, V; Viñas, I; Usall, J; Torres, R; Solsona, C; Abadias, M; Teixidó, N

    2012-05-01

    To prepare commercially acceptable formulations of Bacillus subtilis CPA-8 by spray-drying with long storage life and retained efficacy to control peach and nectarine brown rot caused by Monilinia spp. CPA-8 24-h- and 72-h-old cultures were spray dried using 10% skimmed milk, 10% skimmed milk plus 10% MgSO(4) , 10% MgSO(4) and 20% MgSO(4) as carriers/protectants. All carriers/protectants gave good percentages of powder recovery (28-38%) and moisture content (7-13%). CPA-8 survival varied considerably among spray-dried 24-h- and 72-h-old cultures. Seventy-two hours culture spray dried formulations showed the highest survival (28-32%) with final concentration products of 1·6-3·3 × 10(9) CFU g(-1) , while viability of 24-h-old formulations was lower than 1%. Spray-dried 72-h-old formulations were selected to subsequent evaluation. Rehydration of cells with water provided a good recovery of CPA-8 dried cells, similar to other complex rehydration media tested. Spray-dried formulations stored at 4 ± 1 and 20 ± 1°C showed good shelf life during 6 months, and viability was maintained or slightly decreased by 0·2-0·3-log. CPA-8 formulations after 4- and 6 months storage were effective in controlling brown rot caused by Monilinia spp. on nectarines and peaches resulting in a 90-100% reduction in disease incidence. Stable and effective formulations of biocontrol agent B. subtilis CPA-8 could be obtained by spray-drying. New shelf-stable and effective formulations of a biocontrol agent have been obtained by spray-drying to control brown rot on peach. © 2012 The Authors. Journal of Applied Microbiology © 2012 The Society for Applied Microbiology.

  9. Comparison of the SRK and CPA equations of state for physical properties of water and methanol

    DEFF Research Database (Denmark)

    Lundstrøm, Carsten; Michelsen, Michael Locht; Kontogeorgis, Georgios

    2006-01-01

    produced together with water, properties of water and additives like methanol and glycol is another target area. Being more polar than hydrocarbons, water, alcohols and glycols may require more advanced models for example an association model like CPA (CubicPlus-Association). This type of model has...... previously been found to be well suited for phase equilibrium calculations on mixtures of hydrocarbons and polar compounds. In this work, SRK (with and without Peneloux volume correction) and CPA are compared for pure water, pure methanol and water-methanol binary mixtures with the purpose of evaluating...

  10. Quality assessment of platelet concentrates prepared by platelet rich plasma-platelet concentrate, buffy coat poor-platelet concentrate (BC-PC and apheresis-PC methods

    Directory of Open Access Journals (Sweden)

    Singh Ravindra

    2009-01-01

    Full Text Available Background: Platelet rich plasma-platelet concentrate (PRP-PC, buffy coat poor-platelet concentrate (BC-PC, and apheresis-PC were prepared and their quality parameters were assessed. Study Design: In this study, the following platelet products were prepared: from random donor platelets (i platelet rich plasma - platelet concentrate (PRP-PC, and (ii buffy coat poor- platelet concentrate (BC-PC and (iii single donor platelets (apheresis-PC by different methods. Their quality was assessed using the following parameters: swirling, volume of the platelet concentrate, platelet count, WBC count and pH. Results: A total of 146 platelet concentrates (64 of PRP-PC, 62 of BC-PC and 20 of apheresis-PC were enrolled in this study. The mean volume of PRP-PC, BC-PC and apheresis-PC was 62.30±22.68 ml, 68.81±22.95 ml and 214.05±9.91 ml and ranged from 22-135 ml, 32-133 ml and 200-251 ml respectively. The mean platelet count of PRP-PC, BC-PC and apheresis-PC was 7.6±2.97 x 1010/unit, 7.3±2.98 x 1010/unit and 4.13±1.32 x 1011/unit and ranged from 3.2-16.2 x 1010/unit, 0.6-16.4 x 1010/unit and 1.22-8.9 x 1011/unit respectively. The mean WBC count in PRP-PC (n = 10, BC-PC (n = 10 and apheresis-PC (n = 6 units was 4.05±0.48 x 107/unit, 2.08±0.39 x 107/unit and 4.8±0.8 x 106/unit and ranged from 3.4 -4.77 x 107/unit, 1.6-2.7 x 107/unit and 3.2 - 5.2 x 106/unit respectively. A total of 26 units were analyzed for pH changes. Out of these units, 10 each were PRP-PC and BC-PC and 6 units were apheresis-PC. Their mean pH was 6.7±0.26 (mean±SD and ranged from 6.5 - 7.0 and no difference was observed among all three types of platelet concentrate. Conclusion: PRP-PC and BC-PC units were comparable in terms of swirling, platelet count per unit and pH. As expected, we found WBC contamination to be less in BC-PC than PRP-PC units. Variation in volume was more in BC-PC than PRP-PC units and this suggests that further standardization is required for preparation of BC

  11. Process Design of Industrial Triethylene Glycol Processes Using the Cubic-Plus-Association (CPA) Equation of State

    DEFF Research Database (Denmark)

    Arya, Alay; Maribo-Mogensen, Bjørn; Tsivintzelis, Ioannis

    2014-01-01

    The Cubic-Plus-Association (CPA) equation of state (EoS) has already been proven to be a successful model for phase equilibrium calculations for systems containing glycols. In the present work, we interface a thermodynamic property package (Thermo System), based on CPA, with Aspen HYSYS through...

  12. Environmental fate and behaviour of the biocontrol agent Bacillus amyloliquefaciens CPA-8 after preharvest application to stone fruit.

    Science.gov (United States)

    Vilanova, Laura; Teixidó, Neus; Usall, Josep; Balsells-Llauradó, Marta; Gotor-Vila, Amparo; Torres, Rosario

    2018-02-01

    Bacillus amyloliquefaciens strain CPA-8 has been described as an effective biocontrol agent to control brown rot in stone fruit for both preharvest and postharvest applications. However, no information about the environmental fate and behaviour of this strain under field conditions is available. The dispersion of the CPA-8 application was evaluated using water-sensitive papers, and complete coverage was observed on the leaves of treated trees, while treatment. On non-treated trees, CPA-8 was detected on leaves until 180 days after treatment, and on weeds, the CPA-8 population was dependent on the distance from the treated trees. A high persistence of CPA-8 was detected on inert materials, such as clothes and gloves worn by handlers and plastic harvesting boxes. More than 99% of the samples with a CPA-8 phenotype were confirmed as CPA-8 using polymerase chain reaction (PCR). This work demonstrated a good distribution, persistence and adaptation of the CPA-8 strain to field and postharvest conditions. Monitoring of dispersion and persistence is an excellent tool to determine the time of application and provides valuable information for registering issues. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  13. 7 CFR 1773.20 - CPA's submission of the auditor's report, report on compliance, report on compliance and on...

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 12 2010-01-01 2010-01-01 false CPA's submission of the auditor's report, report on... for the Submission and Review of the Auditor's Report, Report on Compliance and on Internal Control Over Financial Reporting, and Management Letter § 1773.20 CPA's submission of the auditor's report...

  14. Platelet size and age determine platelet function independently

    International Nuclear Information System (INIS)

    Thompson, C.B.; Jakubowski, J.A.; Quinn, P.G.; Deykin, D.; Valeri, C.R.

    1984-01-01

    A study was undertaken to examine the interaction of platelet size and age in determining in vitro platelet function. Baboon megakaryocytes were labeled in vivo by the injection of 75Se-methionine. Blood was collected when the label was predominantly associated with younger platelets (day 2) and with older platelets (day 9). Size-dependent platelet subpopulations were prepared on both days by counterflow centrifugation. The reactivity of each platelet subpopulation was determined on both days by measuring thrombin-induced aggregation. Platelets were fixed after partial aggregation had occurred by the addition of EDTA/formalin. After removal of the aggregated platelets by differential centrifugation, the supernatant medium was assayed for remaining platelets and 75Se radioactivity. Comparing day 2 and day 9, no significant difference was seen in the rate of aggregation of a given subpopulation. However, aggregation was more rapid in the larger platelet fractions than in the smaller ones on both days. A greater percentage of the 75Se radioactivity appeared in the platelet aggregates on day 2 than on day 9. This effect was independent of platelet size, as it occurred to a similar extent in the unfractionated platelets and in each of the size-dependent platelet subpopulations. The data indicate that young platelets are more active than older platelets. This study demonstrates that size and age are both determinants of platelet function, but by independent mechanisms

  15. Flavanols and Platelet Reactivity

    Directory of Open Access Journals (Sweden)

    Debra A. Pearson

    2005-01-01

    Full Text Available Platelet activity and platelet-endothelial cell interactions are important in the acute development of thrombosis, as well as in the pathogenesis of cardiovascular disease. An increasing number of foods have been reported to have platelet-inhibitory actions, and research with a number of flavanol-rich foods, including, grape juice, cocoa and chocolate, suggests that these foods may provide some protection against thrombosis. In the present report, we review a series of in vivo studies on the effects of flavanol-rich cocoa and chocolate on platelet activation and platelet-dependent primary hemostasis. Consumption of flavanol-rich cocoa inhibited several measures of platelet activity including, epinephrine- and ADP-induced glycoprotein (GP IIb/IIIa and P-Selectin expression, platelet microparticle formation, and epinephrine-collagen and ADP-collagen induced primary hemostasis. The epinephrine-induced inhibitory effects on GP IIb/IIIa and primary hemostasis were similar to, though less robust than those associated with the use of low dose (81 mg aspirin. These data, coupled with information from other studies, support the concept that flavanols present in cocoa and chocolate can modulate platelet function through a multitude of pathways.

  16. Platelet activation and aggregation

    DEFF Research Database (Denmark)

    Jensen, Maria Sander; Larsen, O H; Christiansen, Kirsten

    2013-01-01

    This study introduces a new laboratory model of whole blood platelet aggregation stimulated by endogenously generated thrombin, and explores this aspect in haemophilia A in which impaired thrombin generation is a major hallmark. The method was established to measure platelet aggregation initiated...

  17. Platelet alloimmunization after transfusion

    DEFF Research Database (Denmark)

    Taaning, E; Simonsen, A C; Hjelms, E

    1997-01-01

    BACKGROUND AND OBJECTIVES: The frequency of platelet-specific antibodies after one series of blood transfusions has not been reported, and in multiply transfused patients is controversial. MATERIALS AND METHODS: We studied the frequency of alloimmunization against platelet antigens in 117 patient...

  18. Modeling systems relevant to the biodiesel production using the CPA equation of state

    DEFF Research Database (Denmark)

    Tsivintzelis, Ioannis; Ali, Shahid; Kontogeorgis, Georgios

    2016-01-01

    In this study, CPA parameters for heavy esters, glycerides, organic acids, and glycerol are presented, together with trends of these parameters against the van der Waals volume. Such trends allow the prediction of parameters for compounds for which data are not available. Pure fluid parameters we...

  19. Implementing Assessment Engineering in the Uniform Certified Public Accountant (CPA) Examination

    Science.gov (United States)

    Burke, Matthew; Devore, Richard; Stopek, Josh

    2013-01-01

    This paper describes efforts to bring principled assessment design to a large-scale, high-stakes licensure examination by employing the frameworks of Assessment Engineering (AE), the Revised Bloom's Taxonomy (RBT), and Cognitive Task Analysis (CTA). The Uniform CPA Examination is practice-oriented and focuses on the skills of accounting. In…

  20. Educational Competencies That Mid-Sized CPA Firms Value in Their Professional Accounting Staff

    Science.gov (United States)

    Margheim, Loren; Hora, Judith A.; Pattison, Diane

    2010-01-01

    This study examined the educational competencies mid-sized accounting firm partners value in their professional staff when making promotion decisions to senior, manager, and partner. Mid-sized firms were defined in this study to include all of the non-Big 4 national firms, the large regional CPA firms, and several large local firms. Over 1,380…

  1. An Analysis of CPA Firm Recruiters' Perceptions of Online Masters of Accounting Degrees

    Science.gov (United States)

    Metrejean, Eddie; Noland, Thomas G.

    2011-01-01

    Online education continues to grow at a rapid pace. Assessment of the effectiveness of online programs is needed to differentiate legitimate programs from diploma mills. The authors examined the perceptions of CPA firm recruiters on whether an online Master of Accounting (MACC) matters in the hiring decision. Results show that recruiters do not…

  2. Candidate Performance on the Business Environment and Concepts Section of the CPA Exam

    Science.gov (United States)

    Lindsay, D. H.; Tan, K. B.; Campbell, Annhenrie

    2009-01-01

    This paper examines how differences in curricular design of undergraduate accounting programs influence pass rates on the Business Environment and Concepts Section of the CPA Exam. The association of the pass rate of a school's accounting graduates to the design of the schools accounting program and to other school characteristics was examined…

  3. Extension of the cubic-plus-association (CPA) equation of state to amines

    DEFF Research Database (Denmark)

    Kaarsholm, Mads Kristian; Derawi, Samer; Michelsen, Michael Locht

    2005-01-01

    The cubic-plus-association (CPA) equation of state has been extended to modeling mixtures containing amines. Special focus was given to primary and secondary amines, which are known to self-associate, thus forming hydrogen bonds in mixtures with alkanes. Pure-compound parameters have been determi...

  4. Binding of Thrombin-Activated Platelets to a Fibrin Scaffold through ?IIb?3 Evokes Phosphatidylserine Exposure on Their Cell Surface

    OpenAIRE

    Brzoska, Tomasz; Suzuki, Yuko; Mogami, Hideo; Sano, Hideto; Urano, Tetsumei

    2013-01-01

    Recently, by employing intra-vital confocal microscopy, we demonstrated that platelets expose phosphatidylserine (PS) and fibrin accumulate only in the center of the thrombus but not in its periphery. To address the question how exposure of platelet anionic phospholipids is regulated within the thrombus, an in-vitro experiment using diluted platelet-rich plasma was employed, in which the fibrin network was formed in the presence of platelets, and PS exposure on the platelet surface was analyz...

  5. Defective bone repair in mast cell-deficient Cpa3Cre/+ mice.

    Directory of Open Access Journals (Sweden)

    Jose Luis Ramirez-GarciaLuna

    Full Text Available In the adult skeleton, cells of the immune system interact with those of the skeleton during all phases of bone repair to influence the outcome. Mast cells are immune cells best known for their pathologic role in allergy, and may be involved in chronic inflammatory and fibrotic disorders. Potential roles for mast cells in tissue homeostasis, vascularization and repair remain enigmatic. Previous studies in combined mast cell- and Kit-deficient KitW-sh/W-sh mice (KitW-sh implicated mast cells in bone repair but KitW-sh mice suffer from additional Kit-dependent hematopoietic and non- hematopoietic deficiencies that could have confounded the outcome. The goal of the current study was to compare bone repair in normal wild type (WT and Cpa3Cre/+ mice, which lack mast cells in the absence of any other hematopoietic or non- hematopoietic deficiencies. Repair of a femoral window defect was characterized using micro CT imaging and histological analyses from the early inflammatory phase, through soft and hard callus formation, and finally the remodeling phase. The data indicate 1 mast cells appear in healing bone of WT mice but not Cpa3Cre/+ mice, beginning 14 days after surgery; 2 re-vascularization of repair tissue and deposition of mineralized bone was delayed and dis-organised in Cpa3Cre/+ mice compared with WT mice; 3 the defects in Cpa3Cre/+ mice were associated with little change in anabolic activity and biphasic alterations in osteoclast and macrophage activity. The outcome at 56 days postoperative was complete bridging of the defect in most WT mice and fibrous mal-union in most Cpa3Cre/+ mice. The results indicate that mast cells promote bone healing, possibly by recruiting vascular endothelial cells during the inflammatory phase and coordinating anabolic and catabolic activity during tissue remodeling. Taken together the data indicate that mast cells have a positive impact on bone repair.

  6. Defective bone repair in mast cell-deficient Cpa3Cre/+ mice.

    Science.gov (United States)

    Ramirez-GarciaLuna, Jose Luis; Chan, Daniel; Samberg, Robert; Abou-Rjeili, Mira; Wong, Timothy H; Li, Ailian; Feyerabend, Thorsten B; Rodewald, Hans-Reimer; Henderson, Janet E; Martineau, Paul A

    2017-01-01

    In the adult skeleton, cells of the immune system interact with those of the skeleton during all phases of bone repair to influence the outcome. Mast cells are immune cells best known for their pathologic role in allergy, and may be involved in chronic inflammatory and fibrotic disorders. Potential roles for mast cells in tissue homeostasis, vascularization and repair remain enigmatic. Previous studies in combined mast cell- and Kit-deficient KitW-sh/W-sh mice (KitW-sh) implicated mast cells in bone repair but KitW-sh mice suffer from additional Kit-dependent hematopoietic and non- hematopoietic deficiencies that could have confounded the outcome. The goal of the current study was to compare bone repair in normal wild type (WT) and Cpa3Cre/+ mice, which lack mast cells in the absence of any other hematopoietic or non- hematopoietic deficiencies. Repair of a femoral window defect was characterized using micro CT imaging and histological analyses from the early inflammatory phase, through soft and hard callus formation, and finally the remodeling phase. The data indicate 1) mast cells appear in healing bone of WT mice but not Cpa3Cre/+ mice, beginning 14 days after surgery; 2) re-vascularization of repair tissue and deposition of mineralized bone was delayed and dis-organised in Cpa3Cre/+ mice compared with WT mice; 3) the defects in Cpa3Cre/+ mice were associated with little change in anabolic activity and biphasic alterations in osteoclast and macrophage activity. The outcome at 56 days postoperative was complete bridging of the defect in most WT mice and fibrous mal-union in most Cpa3Cre/+ mice. The results indicate that mast cells promote bone healing, possibly by recruiting vascular endothelial cells during the inflammatory phase and coordinating anabolic and catabolic activity during tissue remodeling. Taken together the data indicate that mast cells have a positive impact on bone repair.

  7. Measurement of platelet aggregation, independently of patient platelet count

    DEFF Research Database (Denmark)

    Vinholt, P J; Frederiksen, H; Hvas, A-M

    2017-01-01

    with collagen-related peptide). Platelet aggregation had a negative predictive value of 100% for a bleeding tendency among patients. Conclusion The established platelet aggregation assay was applicable for thrombocytopenic patients, and improved the identification of bleeding risk.......Essentials •Platelet function may influence bleeding risk in thrombocytopenia, but useful tests are needed. •A flow cytometric platelet aggregation test independent of the patient platelet count was made. •Platelet aggregation was reduced in thrombocytopenic patients with hematological cancer....... •High platelet aggregation ruled out bleeding tendency in thrombocytopenic patients. Summary Background Methods for testing platelet aggregation in thrombocytopenia are lacking. Objective To establish a flow-cytometric test of in vitro platelet aggregation independently of the patient's platelet count...

  8. Platelet-collagen adhesion enhances platelet aggregation induced by binding of VWF to platelets

    International Nuclear Information System (INIS)

    Laduca, F.M.; Bell, W.R.; Bettigole, R.E.

    1987-01-01

    Ristocetin-induced platelet aggregation (RIPA) was evaluated in the presence of platelet-collagen adhesion. RIPA of normal donor platelet-rich plasma (PRP) demonstrated a primary wave of aggregation mediated by the binding of von Willebrand factor (VWF) to platelets and a secondary aggregation wave, due to a platelet-release reaction, initiated by VWF-platelet binding and inhibitable by acetylsalicylic acid (ASA). An enhanced RIPA was observed in PRP samples to which collagen had been previously added. These subthreshold concentrations of collagen, which by themselves were insufficient to induce aggregation, caused measurable platelet-collagen adhesion. Subthreshold collagen did not cause microplatelet aggregation, platelet release of [ 3 H]serotonin, or alter the dose-responsive binding of 125 I-labeled VWF to platelets, which occurred with increasing ristocetin concentrations. However, ASA inhibition of the platelet release reaction prevented collagen-enhanced RIPA. These results demonstrate that platelet-collagen adhesion altered the platelet-release reaction induced by the binding of VWF to platelets causing a platelet-release reaction at a level of VWF-platelet binding not normally initiating a secondary aggregation. These findings suggest that platelet-collagen adhesion enhances platelet function mediated by VWF

  9. Taurine and platelet aggregation

    International Nuclear Information System (INIS)

    Nauss-Karol, C.; VanderWende, C.; Gaut, Z.N.

    1986-01-01

    Taurine is a putative neurotransmitter or neuromodulator. The endogenous taurine concentration in human platelets, determined by amino acid analysis, is 15 μM/g. In spite of this high level, taurine is actively accumulated. Uptake is saturable, Na + and temperature dependent, and suppressed by metabolic inhibitors, structural analogues, and several classes of centrally active substances. High, medium and low affinity transport processes have been characterized, and the platelet may represent a model system for taurine transport in the CNS. When platelets were incubated with 14 C-taurine for 30 minutes, then resuspended in fresh medium and reincubated for one hour, essentially all of the taurine was retained within the cells. Taurine, at concentrations ranging from 10-1000 μM, had no effect on platelet aggregation induced by ADP or epinephrine. However, taurine may have a role in platelet aggregation since 35-39% of the taurine taken up by human platelets appears to be secreted during the release reaction induced by low concentrations of either epinephrine or ADP, respectively. This release phenomenon would imply that part of the taurine taken up is stored directly in the dense bodies of the platelet

  10. Platelet concentration in platelet concentrates and periodontal regeneration-unscrambling the ambiguity

    Directory of Open Access Journals (Sweden)

    A Suchetha

    2015-01-01

    Full Text Available Context: Platelet-rich-plasma (PRP and Platelet-rich-fibrin (PRF are extensively used autologous platelet concentrates in periodontal regeneration, and PRF has a better efficacy as compared to PRP. The rationale for this difference has often been attributed to the difference in the structure of the fibrin matrix. However, the effect of concentration of platelets on the regenerative potential of these concentrates is obscure. Aims: The study was conducted to evaluate and compare, clinically and radiographically, the efficacy of PRF and PRP in the treatment of periodontal endosseous defects and to assess the effect of platelet concentration on periodontal regeneration. Materials and Methods: Twenty intrabony defects were selected and divided into two groups randomly by the coin toss method. Group I received PRP and Group II subjects were treated with PRF. The platelet counts in PRP and PRF were analyzed. Clinical and radiological parameters were assessed at baseline and 3, 6, and 9 months postoperatively. Statistical Analysis: Kruskal–Wallis Chi-square test, Wilcoxon signed rank test, t-test, and Spearman's rank correlation were used for statistical analysis of data. Results: There was statistically significant improvement in all the parameters in the two groups except in relation to gingival recession. There was a statistically significant difference between the platelet count in Group I and Group II (P = 0.002. Conclusion: PRP and PRF appear to have nearly comparable effects in terms of periodontal regeneration. The concentration of platelets appears to play a paradoxical role in regeneration. The regenerative potential of platelets appears to be optimal within a limited range.

  11. Platelet kinetics with indium-111 platelets: comparison with chromium-51 platelets

    International Nuclear Information System (INIS)

    Peters, A.M.; Lavender, J.P.

    1983-01-01

    The application of 111In-oxine to platelet labeling has contributed to the understanding of platelet kinetics along three lines: 1. It allows the measurement of new parameters of splenic function, such as the intrasplenic platelet transit time, which has shed new light on the physiology of splenic blood cell handling. 2. It facilitates the measurement of platelet life span in conditions, such as ITP, in which 51Cr may undergo undesirable elution from the platelet as a result of platelet-antibody interaction. 3. It allows the determination of the fate of platelets, that is, the site of platelet destruction in conditions in which reduced platelet life span is associated with abnormal platelet consumption, as a result of either premature destruction of ''abnormal'' platelets by the RE system, or the consumption (or destruction) of normal platelets after their interaction with an abnormal vasculature. Future research using 111In platelets may yield further valuable information on the control as well as the significance of intrasplenic platelet pooling, on the role of platelets in the development of chronic vascular lesions, and on the sites of platelet destruction in ITP. With regard to the latter, methods will have to be developed for harvesting sufficient platelets representative of the total circulating platelet population from severely thrombocytopenic patients for autologous platelet labeling. This would avoid the use of homologous platelets, which is likely to be responsible for some of the contradictory data relating to the use of radiolabeled platelet studies for the prediction of the response of patients with ITP to splenectomy

  12. Thermo-mechanical stress analysis in platelet reinforced composites with bonded and debonded platelet end

    International Nuclear Information System (INIS)

    Fattahi, A. M.; Moaddab, E.; Bibishahrbanoei, N.

    2015-01-01

    An analytical model has been performed to analyze the stress transfer in platelet reinforced composite subjected to both tensile loading and residual thermal stresses. Two sets of the matrix/platelet displacement solutions, which were called respectively as the far-field solution and the transient solution, were exactly derived based on the theory of elasticity. These two sets of the displacement solutions were then superposed to obtain simplified analytical expressions for the matrix/platelet stress field components. The main difference with the previous works here were that the thermal residual stresses were considered in this article. The analytical results obtained here are then validated by the FEM modeling. Interestingly, good agreements are found between the analytical and numerical predictions. Another superiority of the proposed analytical model was in its capability of solving problems with platelet/matrix debonding defect.

  13. Radioimmunoassay of platelet proteins

    International Nuclear Information System (INIS)

    Pepper, D.S.

    1987-01-01

    The radioimmunoassay of platelet-specific proteins has proven to be an excellent way of monitoring platelet activation in vivo. In contrast to earlier methods such as aggregometry, which has been the major tool used in the evaluation of antiplatelet drugs, the RIAs are capable of working with samples which have been subjected to physiological conditions such as haematocrit, oxygen tension, shear rate and ionized calcium concentration. Also, in contrast to aggregometry, no choice of agonist is necessary. Thus, for the first time it has been possible to monitor the effects of therapeutic intervention with drugs upon the platelet release reaction in vivo. It seems reasonable to equate the release reaction in vivo with activation in vivo, though the stimuli necessarily remain unknown. Nevertheless, the fact that a significant number of the compounds mentioned in Table 3 are indeed capable of reducing platelet activation in vivo and that this effect can be measured objectively is a major step forward in our understanding of platelet pharmacology. Two important goals remain to be achieved, however, the establishment of nonhuman animal models for the evaluation of newer compounds in vivo and longer-term goal of proving in the clinical setting the relevance or otherwise of platelet activation per se to the clinical outcome of a particular disease. In this respect, the availability of accurate, reliable and specific radioimmunoassays has a central role

  14. Comparative performance of Aspergillus galactomannan ELISA and PCR in sputum from patients with ABPA and CPA.

    Science.gov (United States)

    Fayemiwo, Samuel; Moore, Caroline B; Foden, Philip; Denning, David W; Richardson, Malcolm D

    2017-09-01

    Galactomannan (GM) and Aspergillus DNA detection are useful tools for the diagnosis of invasive pulmonary aspergillosis (IPA), primarily in blood and bronchoscopy samples. This study aimed to evaluate the utility of both markers for detection of Aspergillus in sputum from patients with allergic bronchopulmonary aspergillosis (ABPA) and chronic pulmonary aspergillosis (CPA). ABPA or CPA demographic patient data were retrieved. This retrospective observational audit included 159 patients with at least one sputum pair. 223 sputum sample pairs were analysed, as well as six control samples for GM only. Real time PCR was performed following sputum DNA extraction using the MycAssay™ Aspergillus kit and cycle thresholds were subtracted from 38 to give positive values (transformed Ct, TCt). The mean age of the patients was 61.81years (SD: ±11.06; range 29-100). One hundred and twenty-six (79.2%) had CPA. Cultures were positive for fungi in 13.1% of the samples, and A. fumigatus was the commonest (11.9%) fungus isolated. Receiver operating characteristic (ROC curve) analysis of sputum GM comparing TCt of >0.0, and >2.0 to derive GMI cut-off values showed a cut-off of 6.5. About 50% of sputa with strongly positive PCR values had GM values>6.5. Two of six (33%) control samples had GM indices>6.5. It is not clear that GM determinations in sputum are useful for diagnosis of either CPA or ABPA, or following therapy. Crown Copyright © 2017. Published by Elsevier B.V. All rights reserved.

  15. Genetics Home Reference: gray platelet syndrome

    Science.gov (United States)

    ... disorder, platelet-type, 4 deficient alpha granule syndrome GPS grey platelet syndrome platelet alpha-granule deficiency platelet ... on PubMed Central Kahr WH, Hinckley J, Li L, Schwertz H, Christensen H, Rowley JW, Pluthero FG, ...

  16. Comparison of 11-C-Palmitic Acid (CPA), and 123-I-heptadecanoic acid (IHA) turnover in human heart

    International Nuclear Information System (INIS)

    Notohamiprodjo, G.; Schmid, A.; Spohr, G.; Vyska, K.; Feinendegen, L.E.

    1985-01-01

    This study was designed to compare the results obtained with IHA in the investigation of myocardial fatty acid metabolism (MFAM) with those obtained by the use of CPA.- 8 patients (pts) without clinical signs of heart or metabolic disease were investigated under rest and fasting condition by dynamic PET following i.v. injection of 3 mCi CPA and by conventional scintigraphy following i.v. injection of 3 mCi IHA. Data were collected over a period of 90 min (frame rate was 1/min) and corrected for blood activity and catabolically released 123-I.-In 6 pts a good agreement between CPA and IHA data was observed. The activity release from the myocardium in these cases was biexponential. The ratio Q ranged between 0.7 and 6.7. -In the remaining 2 pts significant discrepancies between CPA and IHA data were observed. Since these pts were known to have cardiac neurosis and the first measurement was carried out with CPA, the authors assumed that the anxiety of the pt during CPA examination is responsible for the changing of the MFAM. This was confirmed by examination of these pts with IHA under mental stress. In both vases the data obtained by the use of CPA agree closely with those obtained by the use of IHA under mental stress. These data indicate that both CPA and IHa are applicable for studying MFAM and that in external assessment of MFAM, not only the dietary status, but also the mental state of the pts should be considered

  17. Comparison of 11-C-Palmitic Acid (CPA), and 123-I-heptadecanoic acid (IHA) turnover in human heart

    Energy Technology Data Exchange (ETDEWEB)

    Notohamiprodjo, G.; Schmid, A.; Spohr, G.; Vyska, K.; Feinendegen, L.E.

    1985-05-01

    This study was designed to compare the results obtained with IHA in the investigation of myocardial fatty acid metabolism (MFAM) with those obtained by the use of CPA.- 8 patients (pts) without clinical signs of heart or metabolic disease were investigated under rest and fasting condition by dynamic PET following i.v. injection of 3 mCi CPA and by conventional scintigraphy following i.v. injection of 3 mCi IHA. Data were collected over a period of 90 min (frame rate was 1/min) and corrected for blood activity and catabolically released 123-I.-In 6 pts a good agreement between CPA and IHA data was observed. The activity release from the myocardium in these cases was biexponential. The ratio Q ranged between 0.7 and 6.7. -In the remaining 2 pts significant discrepancies between CPA and IHA data were observed. Since these pts were known to have cardiac neurosis and the first measurement was carried out with CPA, the authors assumed that the anxiety of the pt during CPA examination is responsible for the changing of the MFAM. This was confirmed by examination of these pts with IHA under mental stress. In both vases the data obtained by the use of CPA agree closely with those obtained by the use of IHA under mental stress. These data indicate that both CPA and IHa are applicable for studying MFAM and that in external assessment of MFAM, not only the dietary status, but also the mental state of the pts should be considered.

  18. Platelet size does not correlate with platelet age.

    Science.gov (United States)

    Thompson, C B; Love, D G; Quinn, P G; Valeri, C R

    1983-08-01

    The relationship between platelet size and in vivo aging was investigated in the baboon using size-dependent platelet subpopulations separated by counterflow centrifugation. The separation characteristics, size, lactate dehydrogenase (LDH) activity, and dense-body content of the baboon platelet subpopulations were similar to those previously observed in studies of human platelets. Three independent labeling techniques were used: (1) in vivo labeling with 75Se-methionine, (2) in vitro labeling with 51Cr, and (3) in vivo labeling with 14C-serotonin. Maximal incorporation of all three labels showed a close correlation between the mean platelet volume (MPV) of each fraction and the platelet radioactivity. The onset of incorporation and rate of accumulation of 75Se-methionine were comparable in all fractions when corrected for differences in volume, suggesting that platelet size heterogeneity was present from the time of release of the platelets from the bone marrow. Survival studies using 51Cr and 14C-serotonin showed no translocation of the label from one fraction to another in the circulation over time. In vivo survival values for the three radionuclides showed a slight but significant correlation between the lifespan and the MPV of the fractions. The data suggest that large platelets were not younger platelets, but rather platelets with a longer life-span. Platelet size heterogeneity is the result of production factors in the bone marrow and not maturation in the circulation.

  19. Platelet size does not correlate with platelet age

    International Nuclear Information System (INIS)

    Thompson, C.B.; Love, D.G.; Quinn, P.G.; Valeri, C.R.

    1983-01-01

    The relationship between platelet size and in vivo aging was investigated in the baboon using size-dependent platelet subpopulations separated by counterflow centrifugation. The separation characteristics, size, lactate dehydrogenase (LDH) activity, and dense-body content of the baboon platelet subpopulations were similar to those previously observed in studies of human platelets. Three independent labeling techniques were used: (1) in vivo labeling with 75 Se-methionine, (2) in vitro labeling with 51 Cr, and (3) in vivo labeling with 14C-serotonin. Maximal incorporation of all three labels showed a close correlation between the mean platelet volume (MPV) of each fraction and the platelet radioactivity. The onset of incorporation and rate of accumulation of 75 Se-methionine were comparable in all fractions when corrected for differences in volume, suggesting that platelet size heterogeneity was present from the time of release of the platelets from the bone marrow. Survival studies using 51 Cr and 14 C-serotonin showed no translocation of the label from one fraction to another in the circulation over time. In vivo survival values for the three radionuclides showed a slight but significant correlation between the lifespan and the MPV of the fractions. The data suggest that large platelets were not younger platelets, but rather platelets with a longer life-span. Platelet size heterogeneity is the result of production factors in the bone marrow and not maturation in the circulation

  20. Establishment of A Novel Chinese Human Lung Adenocarcinoma Cell Line CPA-Yang3 and Its Real Bone Metastasis Clone CPA-Yang3BM in Immunodeficient Mice

    Directory of Open Access Journals (Sweden)

    Shunfang YANG

    2011-02-01

    Full Text Available Background and objective The recurrence and metastasis of lung cancer is a tough problem worldwide. The aim of this study is to establish a novel Chinese lung adenocarcinoma cell line and its real bone-seeking clone sub-line for exploring the molecular mechanism of lung cancer metastasis. Methods The cells came from the pleural effusion of a sixtyfive years old female patient with lung adenocarcinoma and supraclavicular lymph node metastases. The gene expression was detected by real-time quantitative PCR. Intracardiac injection of the cells into nude mice was performed and in vivo imaging was obtained by bone scintigraphy and conventional radiography. Bone metastases were determined on bone scintigraphy and then the lesions were resected under deep anesthesia for bone metastasis cancer cell culture. The process was repeated for four cycles to obtain a real bone-seeking clone. Results The tumorigenesis rate started at 4th passage in immunodeficient mice via subcutaneously and as well as later passages. Approximately 1×106 cancer cells were injected into left cardiac ventricle of immunodeficient mice resulted bone metastasis sites were successfully revealed by bone scintigraphy and pathological diagnosis, the mandible (100%, scapula (33%, humerus (50%, vertebral column (50%, femur (66.7% and accompanied invasion with other organs, the adrenal gland (17%, pulmonary (33%, liver (50%, submaxillary gland (33% in the mice after inoculation two-three weeks. The chromosome karyotype analysis of the cells was subdiploid. Quantitative real-time PCR was used to examined and compared with SPC-A-1 lung adenocarcinoma, ESM1, VEGF-C, IL-6, IL-8, AR, SVIL, FN1 genes were overexpress. The novel cell was named CPA-Yang3. The femur metastasis cell was repeated in vivo-in vitro-in vivo with three cycles and harvested a real bone metastasis clone. It was named CPA-Yang3BM. Conclusion Tne characteristics of novel strain CPAYang3 is a highly metastasis cell line of

  1. Platelet function in brown bear (Ursus arctos compared to man

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    Särndahl Eva

    2010-06-01

    Full Text Available Abstract Background Information on hemostasis and platelet function in brown bear (Ursus arctos is of importance for understanding the physiological, protective changes during hibernation. Objective The study objective was to document platelet activity values in brown bears shortly after leaving the den and compare them to platelet function in healthy humans. Methods Blood was drawn from immobilized wild brown bears 7-10 days after leaving the den in mid April. Blood samples from healthy human adults before and after clopidogrel and acetylsalicylic acid administration served as control. We analyzed blood samples by standard blood testing and platelet aggregation was quantified after stimulation with various agonists using multiple electrode aggregometry within 3 hours of sampling. Results Blood samples were collected from 6 bears (3 females between 1 and 16 years old and from 10 healthy humans. Results of adenosine diphosphate, aspirin, and thrombin receptor activating peptide tests in bears were all half or less of those in humans. Platelet and white blood cell counts did not differ between species but brown bears had more and smaller red blood cells compared with humans. Conclusion Using three different tests, we conclude that platelet function is lower in brown bears compared to humans. Our findings represent the first descriptive study on platelet function in brown bears and may contribute to explain how bears can endure denning without obvious thrombus building. However, the possibility that our findings reflect test-dependent and not true biological variations in platelet reactivity needs further studies.

  2. Generation of Platelet Microparticles after Cryopreservation of Apheresis Platelet Concentrates Contributes to Hemostatic Activity

    Directory of Open Access Journals (Sweden)

    İbrahim Eker

    2017-03-01

    Full Text Available Objective: In the last decade, substantial evidence has accumulated about the use of cryopreserved platelet concentrates, especially in trauma. However, little reference has been made in these studies to the morphological and functional changes of platelets. Recently platelets have been shown to be activated by cryopreservation processes and to undergo procoagulant membrane changes resulting in the generation of platelet-derived microparticles (PMPs, platelet degranulation, and release of platelet-derived growth factors (PDGFs. We assessed the viabilities and the PMP and PDGF levels of cryopreserved platelets, and their relation with thrombin generation. Materials and Methods: Apheresis platelet concentrates (APCs from 20 donors were stored for 1 day and cryopreserved with 6% dimethyl sulfoxide. Cryopreserved APCs were kept at -80 °C for 1 day. Thawed APCs (100 mL were diluted with 20 mL of autologous plasma and specimens were analyzed for viabilities and PMPs by flow cytometry, for thrombin generation by calibrated automated thrombogram, and for PDGFs by enzyme-linked immunosorbent assay testing. Results: The mean PMP and PDGF levels in freeze-thawed APCs were significantly higher (2763±399.4/μL vs. 319.9±80.5/μL, p<0.001 and 550.9±73.6 pg/mL vs. 96.5±49 pg/mL, p<0.001, respectively, but the viability rates were significantly lower (68.2±13.7% vs. 94±7.5%, p<0.001 than those of fresh APCs. The mean endogenous thrombin potential (ETP of freeze-thawed APCs was significantly higher than that of the fresh APCs (3406.1±430.4 nM.min vs. 2757.6±485.7 nM.min, p<0.001. Moreover, there was a significant positive poor correlation between ETP levels and PMP levels (r=0.192, p=0.014. Conclusion: Our results showed that, after cryopreservation, while levels of PMPs were increasing, significantly higher and earlier thrombin formation was occurring in the samples analyzed despite the significant decrease in viability. Considering the damage caused

  3. Platelet aggregation following trauma

    DEFF Research Database (Denmark)

    Windeløv, Nis A; Sørensen, Anne M; Perner, Anders

    2014-01-01

    We aimed to elucidate platelet function in trauma patients, as it is pivotal for hemostasis yet remains scarcely investigated in this population. We conducted a prospective observational study of platelet aggregation capacity in 213 adult trauma patients on admission to an emergency department (ED...... severity score (ISS) was 17; 14 (7%) patients received 10 or more units of red blood cells in the ED (massive transfusion); 24 (11%) patients died within 28 days of trauma: 17 due to cerebral injuries, four due to exsanguination, and three from other causes. No significant association was found between...... aggregation response and ISS. Higher TRAP values were associated with death due to cerebral injuries (P 

  4. Kinetics of platelets in dogs with thrombocytopenia induced by antiglycoprotein IIb/IIIa receptor monoclonal antibody

    International Nuclear Information System (INIS)

    Hosono, Makoto; Sone, Naoaki; Endo, Keigo; Saga, Tsuneo; Kobayashi, Hisataka; Hosono, Masako N.; Sakahara, Harumi; Yasunaga, Kojiro; Konishi, Junji

    1995-01-01

    To experimentally assess the kinetics of platelets in thrombocytopenia, we constructed a canine model using 111 In-oxine labeled autologous platelets and an intact antiplatelet monoclonal antibody (MAb) NNKY2-11 (IgG2a). With the infusion of radiolabeled autologous platelets into dogs, the peripheral platelet count and blood radioactivity level were examined, and the radioactivity in the liver, spleen and heart was determined with scintigraphic analysis. Thereafter, i.v. injection of 100 μg/kg of NNKY2-11 had no effect on platelet counts or the biodistribution of radiolabeled platelets. However, 200 and 300 μg/kg of MAb reduced the platelets, and the radioactivity of the liver and spleen augmented clearly after injection of MAb. Platelet radioactivity in serum, which had decreased after MAb infusion, did not recover, even when peripheral platelet counts returned to the normal levels, indicating that these new platelets might be derived from the platelet-storage pool or new thrombocytogenesis. This model of antiplatelet MAb induced thrombocytopenia seems to be useful for analyzing the kinetics of platelets in thrombocytopenia

  5. Assessment of platelet function in healthy cats in response to commonly prescribed antiplatelet drugs using three point-of-care platelet function tests.

    Science.gov (United States)

    Ho, Kimberly K; Abrams-Ogg, Anthony Cg; Wood, R Darren; O'Sullivan, M Lynne; Kirby, Gordon M; Blois, Shauna L

    2017-06-01

    Objectives The objective was to determine if decreased platelet function could be detected after treatment with aspirin and/or clopidogrel in healthy cats using three point-of-care platelet function tests that evaluate platelet function by different methods: Multiplate (by impedance), Platelet Function Analyzer 100 (by mechanical aperture closure) and Plateletworks (by platelet counting). Methods Thirty-six healthy cats were randomly assigned to receive one of three oral treatments over an 8 day period: (1) aspirin 5 mg q72h; (2) aspirin 20.25 mg q72h; or (3) clopidogrel 18.75 mg q24h. Cats treated with 5 and 20.25 mg aspirin also received clopidogrel on days 4-8. Platelet aggregation in response to adenosine diphosphate and collagen ± arachidonic acid was assessed on days 1 (baseline), 4 and 8. Aspirin and clopidogrel metabolites were measured by high-performance liquid chromatography. Platelet function in response to treatment was analyzed by ANCOVA, linear regression and Spearman correlation. Results The only solitary aspirin effect was detected using Plateletworks with collagen in cats treated with 20.25 mg. The only effect detected by Multiplate was using arachidonic acid in cats treated with both aspirin 20.25 mg and clopidogrel. All clopidogrel treatment effects were detected by Platelet Function Analyzer 100, Plateletworks (adenosine diphosphate) and Plateletworks (collagen). Drug metabolites were present in all cats, but concentrations were minimally correlated to platelet function test results. Conclusions and relevance Platelet Function Analyzer 100 and Plateletworks using adenosine diphosphate ± collagen agonists may be used to detect decreased platelet function in response to clopidogrel treatment. Either aspirin is not as effective an antiplatelet drug as clopidogrel, or the tests used were not optimal to measure aspirin effect. Cats with heart disease are commonly prescribed antiplatelet drugs to decrease the risk of aortic thromboembolism

  6. Protection of neuroblastoma Neuro2A cells from hypoxia-induced apoptosis by cyclic phosphatidic acid (cPA.

    Directory of Open Access Journals (Sweden)

    Mari Gotoh

    Full Text Available Cyclic phosphatidic acid (cPA is a naturally occurring phospholipid mediator with a unique cyclic phosphate ring at the sn-2 and sn-3 positions of its glycerol backbone. We have previously shown that cPA significantly suppresses ischemia-induced delayed neuronal death and the accumulation of glial fibrillary acidic protein in the CA1 region of the rat hippocampus. These results indicated that the systemic administration of cPA can protect hippocampal neurons against ischemia-induced delayed neuronal cell death. In the current study, we investigated the effects of cPA on neuronal cell death caused by hypoxia in vitro and the molecular mechanisms underlying these effects. We used cobalt chloride (CoCl(2 to expose cells to hypoxic conditions in vitro. Treating mouse neuroblastoma (Neuro2A cells with CoCl(2 induced nuclear DNA condensation and phosphatidylserine exposure. However, adding cPA led to the suppression of CoCl(2-induced apoptosis in a cPA dose-dependent manner and attenuated the increase in the Bax/Bcl-2 ratio caused by CoCl(2. Quantitative PCR analysis showed that Neuro2A cells strongly express the LPA(1, LPA(2, and LPA(6, which are G-protein coupled receptors that can be activated by cPA. To date, LPA(1 and LPA(2 have been reported to exhibit antiapoptotic activity. Therefore, to assess the roles of LPA(1 and LPA(2 on cPA-induced neuroprotective functions, Ki16425, a selective LPA(1 and LPA(3 antagonist, was adopted to know the LPA(1 function and siRNA was used to knockdown the expression of LPA(2. On the basis of our results, we propose that cPA-induced protection of Neuro2A cells from CoCl(2-induced hypoxia damage is mediated via LPA(2.

  7. Blood platelet inventory management

    NARCIS (Netherlands)

    Haijema, R.; van Dijk, N. M.; van der Wal, J.; Boucherie, Richard J.; van Dijk, Nico M.

    2017-01-01

    This paper illustrates how MDP or Stochastic Dynamic Programming (SDP) can be used in practice for blood management at blood banks; both to set regular production quantities for perishable blood products (platelets) and how to do so in irregular periods (as holidays). The state space is too large to

  8. Modelling the phase equilibria of multicomponent mixtures containing CO2, alkanes, water, and/or alcohols using the quadrupolar CPA equation of state

    DEFF Research Database (Denmark)

    Bjørner, Martin Gamel; Kontogeorgis, Georgios

    2016-01-01

    In this work, a quadrupolar cubic plus association (qCPA) equation of state is evaluated for its ability to predict the phase equilibria of multicomponent mixtures containing CO2 and alkanes, alcohols, and/or water. A single binary interaction parameter is employed in qCPA for all binary combinat...... CPA yields the best results of all the models for the prediction of dew point pressures....

  9. Effects of delayed laboratory processing on platelet serotonin levels.

    Science.gov (United States)

    Sanner, Jennifer E; Frazier, Lorraine; Udtha, Malini

    2013-01-01

    Despite the availability of established guidelines for measuring platelet serotonin, these guidelines may be difficult to follow in a hospital setting where time to processing may vary from sample to sample. The purpose of this study was to evaluate the effect of the time to processing of human blood samples on the stability of the enzyme-linked immunosorbent assay (ELISA) for the determination of platelet serotonin levels in human plasma. Human blood samples collected from a convenience sample of eight healthy volunteers were analyzed to determine platelet serotonin levels from plasma collected in ethylene diamine tetra acetic acid (EDTA) tubes and stored at 4°C for 3 hr, 5 hr, 8 hr, and 12 hr. Refrigeration storage at 4°C for 3 hr, 5 hr, 8 hr, and 12 hr altered the platelet serotonin measurement when compared to immediate processing. The bias for the samples stored at 4°C for 3 hr was 102.3 (±217.39 ng/10(9) platelets), for 5 hr was 200.1 (±132.76 ng/10(9) platelets), for 8 hr was 146.9 (±221.41 ng/10(9) platelets), and for 12 hr was -67.6 (±349.60 ng/10(9) platelets). Results from this study show that accurate measurement of platelet serotonin levels is dependent on time to processing. Researchers should therefore follow a standardized laboratory guideline for obtaining immediate platelet serotonin levels after blood sample collection.

  10. Alternatives to allogeneic platelet transfusion.

    Science.gov (United States)

    Desborough, Michael J R; Smethurst, Peter A; Estcourt, Lise J; Stanworth, Simon J

    2016-11-01

    Allogeneic platelet transfusions are widely used for the prevention and treatment of bleeding in thrombocytopenia. Recent evidence suggests platelet transfusions have limited efficacy and are associated with uncertain immunomodulatory risks and concerns about viral or bacterial transmission. Alternatives to transfusion are a well-recognised tenet of Patient Blood Management, but there has been less focus on different strategies to reduce bleeding risk by comparison to platelet transfusion. Direct alternatives to platelet transfusion include agents to stimulate endogenous platelet production (thrombopoietin mimetics), optimising platelet adhesion to endothelium by treating anaemia or increasing von Willebrand factor levels (desmopressin), increasing formation of cross-linked fibrinogen (activated recombinant factor VII, fibrinogen concentrate or recombinant factor XIII), decreasing fibrinolysis (tranexamic acid or epsilon aminocaproic acid) or using artificial or modified platelets (cryopreserved platelets, lyophilised platelets, haemostatic particles, liposomes, engineered nanoparticles or infusible platelet membranes). The evidence base to support the use of these alternatives is variable, but an area of active research. Much of the current randomised controlled trial focus is on evaluation of the use of thrombopoietin mimetics and anti-fibrinolytics. It is also recognised that one alternative strategy to platelet transfusion is choosing not to transfuse at all. © 2016 John Wiley & Sons Ltd.

  11. Recent applications of the cubic-plus-association (CPA) equation of state to industrially important systems

    DEFF Research Database (Denmark)

    Folas, Georgios; Derawi, Samer; Michelsen, Michael Locht

    2005-01-01

    . Very satisfactory VLE and SLE prediction is achieved for alcohol-hydrocarbon systems, while the sensitivity of the LLE to the interaction parameter is demonstrated. It has been shown that CPA can perform VLE/LLE/SLE calculations in the case of alcohol-hydrocarbon binary systems with a single...... interaction parameter. Satisfactory SLE correlation of alcohol/glycol-water systems is achieved using a single interaction parameter over an extended temperature range. Moreover, satisfactory prediction was achieved for the multiphase equilibria of the mixture acetic acid-water-hexane based solely on binary...

  12. Distribution of MEG and methanol in well-defined hydrocarbon and water systems: Experimental measurement and modeling using the CPA EoS

    DEFF Research Database (Denmark)

    Riaz, Muhammad; Yussuf, Mustafe A.; Kontogeorgis, Georgios

    2013-01-01

    + water. These data are satisfactorily correlated (binaries) and predicted (ternaries) using Cubic Plus Association (CPA) equation of state (EoS). CPA is also applied to binary LLE of aromatic hydrocarbon + water and VLE of methane + methanol. Finally the distribution of water and inhibitors (methanol...... and MEG) in various phases is modeled using CPA. The hydrocarbon phase consists of mixture-1 (methane, ethane, n-butane) or mixture-2 (methane, ethane, propane, n-butane, n-heptane, toluene and n-decane). CPA can satisfactorily predict the water content in the gas phase of the multicomponent systems...

  13. Insomnia, platelet serotonin and platelet monoamine oxidase in chronic alcoholism.

    Science.gov (United States)

    Nenadic Sviglin, Korona; Nedic, Gordana; Nikolac, Matea; Mustapic, Maja; Muck-Seler, Dorotea; Borovecki, Fran; Pivac, Nela

    2011-08-18

    Insomnia is a common sleep disorder frequently occurring in chronic alcoholic patients. Neurobiological basis of insomnia, as well as of alcoholism, is associated with disrupted functions of the main neurotransmitter systems, including the serotonin (5-hydroxytryptamine, 5-HT) system. Blood platelets are considered a limited peripheral model for the central 5-HT neurons, since both platelets and central 5-HT synaptosomes have similar dynamics of 5-HT. Platelet 5-HT concentration and platelet monoamine oxidase type B (MAO-B) are assumed to represent biomarkers for particular symptoms and behaviors in psychiatric disorders. The hypothesis of this study was that platelet 5-HT concentration and platelet MAO-B activity will be altered in chronic alcoholic patients with insomnia compared to comparable values in patients without insomnia. The study included 498 subjects: 395 male and 103 female medication-free patients with alcohol dependence and 502 healthy control subjects: 325 men and 177 women. The effects of early, middle and late insomnia (evaluated using the Hamilton Depression Rating Scale), as well as sex, age and smoking on platelet 5-HT concentration and platelet MAO-B activity were evaluated using one-way ANOVA and multiple regression analysis by the stepwise method. Platelet 5-HT concentration, but not platelet MAO-B activity, was significantly reduced in alcoholic patients with insomnia compared to patients without insomnia. Multiple regression analysis revealed that platelet 5-HT concentration was affected by middle insomnia, smoking and sex, while platelet MAO activity was affected only by sex and age. The present and previous data suggest that platelet 5-HT concentration might be used, after controlling for sex and smoking, as a biomarker for insomnia in alcoholism, PTSD and in rotating shift workers. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  14. Storage of platelets: effects associated with high platelet content in platelet storage containers.

    Science.gov (United States)

    Gulliksson, Hans; Sandgren, Per; Sjödin, Agneta; Hultenby, Kjell

    2012-04-01

    A major problem associated with platelet storage containers is that some platelet units show a dramatic fall in pH, especially above certain platelet contents. The aim of this study was a detailed investigation of the different in vitro effects occurring when the maximum storage capacity of a platelet container is exceeded as compared to normal storage. Buffy coats were combined in large-volume containers to create primary pools to be split into two equal aliquots for the preparation of platelets (450-520×10(9) platelets/unit) in SSP+ for 7-day storage in two containers (test and reference) with different platelet storage capacity (n=8). Exceeding the maximum storage capacity of the test platelet storage container resulted in immediate negative effects on platelet metabolism and energy supply, but also delayed effects on platelet function, activation and disintegration. Our study gives a very clear indication of the effects in different phases associated with exceeding the maximum storage capacity of platelet containers but throw little additional light on the mechanism initiating those negative effects. The problem appears to be complex and further studies in different media using different storage containers will be needed to understand the mechanisms involved.

  15. Nanodiamonds activate blood platelets and induce thromboembolism.

    Science.gov (United States)

    Kumari, Sharda; Singh, Manoj K; Singh, Sunil K; Grácio, José J A; Dash, Debabrata

    2014-03-01

    Nanodiamonds (NDs) have been evaluated for a wide range of biomedical applications. Thus, thorough investigation of the biocompatibility of NDs has become a research priority. Platelets are highly sensitive and are one of the most abundant cell types found in blood. They have a central role in hemostasis and arterial thrombosis. In this study, we aim to investigate the direct and acute effects of carboxylated NDs on platelet function. In this study, pro-coagulant parameters such as platelet aggregability, intracellular Ca(2+) flux, mitochondrial transmembrane potential (ΔΨm), generation of reactive oxygen species, surface exposure of phosphatidylserine, electron microscopy, cell viability assay and in vivo thromboembolism were analyzed in great detail. Carboxylated NDs evoked significant activation of human platelets. When administered intravenously in mice, NDs were found to induce widespread pulmonary thromboembolism, indicating the remarkable thrombogenic potential of this nanomaterial. Our findings raise concerns regarding the putative biomedical applications of NDs pertaining to diagnostics and therapeutics, and their toxicity and prothrombotic properties should be critically evaluated.

  16. Platelet proteome reveals novel pathways of platelet activation and platelet-mediated immunoregulation in dengue.

    Directory of Open Access Journals (Sweden)

    Monique Ramos de Oliveira Trugilho

    2017-05-01

    Full Text Available Dengue is the most prevalent human arbovirus disease worldwide. Dengue virus (DENV infection causes syndromes varying from self-limiting febrile illness to severe dengue. Although dengue pathophysiology is not completely understood, it is widely accepted that increased inflammation plays important roles in dengue pathogenesis. Platelets are blood cells classically known as effectors of hemostasis which have been increasingly recognized to have major immune and inflammatory activities. Nevertheless, the phenotype and effector functions of platelets in dengue pathogenesis are not completely understood. Here we used quantitative proteomics to investigate the protein content of platelets in clinical samples from patients with dengue compared to platelets from healthy donors. Our assays revealed a set of 252 differentially abundant proteins. In silico analyses associated these proteins with key molecular events including platelet activation and inflammatory responses, and with events not previously attributed to platelets during dengue infection including antigen processing and presentation, proteasome activity, and expression of histones. From these results, we conducted functional assays using samples from a larger cohort of patients and demonstrated evidence for platelet activation indicated by P-selectin (CD62P translocation and secretion of granule-stored chemokines by platelets. In addition, we found evidence that DENV infection triggers HLA class I synthesis and surface expression by a mechanism depending on functional proteasome activity. Furthermore, we demonstrate that cell-free histone H2A released during dengue infection binds to platelets, increasing platelet activation. These findings are consistent with functional importance of HLA class I, proteasome subunits, and histones that we found exclusively in proteome analysis of platelets in samples from dengue patients. Our study provides the first in-depth characterization of the platelet

  17. Effects of hormones on platelet aggregation.

    Science.gov (United States)

    Farré, Antonio López; Modrego, Javier; Zamorano-León, José J

    2014-04-01

    Platelets and their activation/inhibition mechanisms play a central role in haemostasis. It is well known agonists and antagonists of platelet activation; however, during the last years novel evidences of hormone effects on platelet activation have been reported. Platelet functionality may be modulated by the interaction between different hormones and their platelet receptors, contributing to sex differences in platelet function and even in platelet-mediated vascular damage. It has suggested aspects that apparently are well established should be reviewed. Hormones effects on platelet activity are included among them. This article tries to review knowledge about the involvement of hormones in platelet biology and activity.

  18. Metal organic framework Cu9Cl2(cpa)6 as tunable molecular magnet

    Science.gov (United States)

    Hamilton, Heather S. C.; Farmer, William M.; Skinner, Samuel F.; ter Haar, Leonard W.

    2018-05-01

    Chemical modifications of the magnetic metal organic framework (MOF) Cu9X2(cpa)6.42H2O (X = F, Cl, Br; cpa = anion of 2-carboxypentonicacid) have been investigated as a means of modifying, in a tunable manner, the magnetism of this 2-D material best described as a triangles-in-triangles (TIT) or triangulated-Kagomé-latttice (TKL). Since numerous theoretical studies have already attempted to describe the enigmatic ground state of this Heisenberg lattice, tunable chemical modifications should provide an excellent opportunity to expand this class of materials for studies concerning fundamental physics of frustrated spins, and applications such as adiabatic demagnetization refrigeration (ADR) that depend on the magnetocaloric effect (MCE). The chemical modification investigated is the intercalation of d- and f-orbital ions into the voids of the framework (channels of nearly 20 Å diameter). Magnetic measurements in the temperature range 1.8 - 300 K confirm signature features of TKL magnetism in intercalated samples persist, specifically: i) large negative Weiss constant (θCW); ii) absence of a phase transition down to 1.8 K; iii) minimum in χMT; iv) low temperature χMT values increasingly divergent at low fields indicating net ferromagnetic correlations; and, v) increasing field dependence of magnetization at low temperatures suggestive of intermediate plateaus, or ferrimagnetism, not saturation.

  19. The CpAL quorum sensing system regulates production of hemolysins CPA and PFO to build Clostridium perfringens biofilms.

    Science.gov (United States)

    Vidal, Jorge E; Shak, Joshua R; Canizalez-Roman, Adrian

    2015-06-01

    Clostridium perfringens strains produce severe diseases, including myonecrosis and enteritis necroticans, in humans and animals. Diseases are mediated by the production of potent toxins that often damage the site of infection, e.g., skin epithelium during myonecrosis. In planktonic cultures, the regulation of important toxins, such as CPA, CPB, and PFO, is controlled by the C. perfringens Agr-like (CpAL) quorum sensing (QS) system. Strains also encode a functional LuxS/AI-2 system. Although C. perfringens strains form biofilm-like structures, the regulation of biofilm formation is poorly understood. Therefore, our studies investigated the role of CpAL and LuxS/AI-2 QS systems and of QS-regulated factors in controlling the formation of biofilms. We first demonstrate that biofilm production by reference strains differs depending on the culture medium. Increased biomass correlated with the presence of extracellular DNA in the supernatant, which was released by lysis of a fraction of the biofilm population and planktonic cells. Whereas ΔagrB mutant strains were not able to produce biofilms, a ΔluxS mutant produced wild-type levels. The transcript levels of CpAL-regulated cpa and pfoA genes, but not cpb, were upregulated in biofilms compared to planktonic cultures. Accordingly, Δcpa and ΔpfoA mutants, in type A (S13) or type C (CN3685) backgrounds, were unable to produce biofilms, whereas CN3685Δcpb made wild-type levels. Biofilm formation was restored in complemented Δcpa/cpa and ΔpfoA/pfoA strains. Confocal microscopy studies further detected CPA partially colocalizing with eDNA on the biofilm structure. Thus, CpAL regulates biofilm formation in C. perfringens by increasing levels of certain toxins required to build biofilms. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  20. The CpAL Quorum Sensing System Regulates Production of Hemolysins CPA and PFO To Build Clostridium perfringens Biofilms

    Science.gov (United States)

    Shak, Joshua R.; Canizalez-Roman, Adrian

    2015-01-01

    Clostridium perfringens strains produce severe diseases, including myonecrosis and enteritis necroticans, in humans and animals. Diseases are mediated by the production of potent toxins that often damage the site of infection, e.g., skin epithelium during myonecrosis. In planktonic cultures, the regulation of important toxins, such as CPA, CPB, and PFO, is controlled by the C. perfringens Agr-like (CpAL) quorum sensing (QS) system. Strains also encode a functional LuxS/AI-2 system. Although C. perfringens strains form biofilm-like structures, the regulation of biofilm formation is poorly understood. Therefore, our studies investigated the role of CpAL and LuxS/AI-2 QS systems and of QS-regulated factors in controlling the formation of biofilms. We first demonstrate that biofilm production by reference strains differs depending on the culture medium. Increased biomass correlated with the presence of extracellular DNA in the supernatant, which was released by lysis of a fraction of the biofilm population and planktonic cells. Whereas ΔagrB mutant strains were not able to produce biofilms, a ΔluxS mutant produced wild-type levels. The transcript levels of CpAL-regulated cpa and pfoA genes, but not cpb, were upregulated in biofilms compared to planktonic cultures. Accordingly, Δcpa and ΔpfoA mutants, in type A (S13) or type C (CN3685) backgrounds, were unable to produce biofilms, whereas CN3685Δcpb made wild-type levels. Biofilm formation was restored in complemented Δcpa/cpa and ΔpfoA/pfoA strains. Confocal microscopy studies further detected CPA partially colocalizing with eDNA on the biofilm structure. Thus, CpAL regulates biofilm formation in C. perfringens by increasing levels of certain toxins required to build biofilms. PMID:25824838

  1. Granulocyte-platelet interactions and platelet fibrinogen receptor exposure

    International Nuclear Information System (INIS)

    Kornecki, E.; Ehrlich, Y.H.; Egbring, R.; Gramse, M.; Seitz, R.; Eckardt, A.; Lukasiewicz, H.; Niewiarowski, S.

    1988-01-01

    The authors have examined the interaction of human granulocyte elastase with human platelets. Incubation of human platelets with human granulocyte elastase exposed active fibrinogen-binding sites as evidenced by 125 I-labeled fibrinogen binding and spontaneous fibrinogen-induced platelet aggregation. The aggregation of platelets by fibrinogen occurred at low concentrations of human granulocyte elastase. Platelets pretreated with human granulocyte elastase exposed an average of 10,500 fibrinogen-binding sites per platelet, i.e., about one-third the number of binding sites exposed by optimal concentrations of ADP. With the use of a polyclonal antiplatelet membrane antibody, the glycoproteins IIb (GPIIb), IIIa (GPIIIa), and a 60,000-Da (60 kDa) protein (66 kDa in a reduced system) derived from GPIIIa were immunoprecipitated from the surface of detergent extracts of human 125 I-radiolabeled platelets pretreated with increasing concentrations of human granulocyte elastase. They conclude that (1) the proteolytic action of human granulocyte elastase on platelet GPIIIa results in the formation of two major hydrolytic products, and (2) human granulocyte elastase exposes active fibrongen-binding sites associated with the GPIIb/GPIIIa complex, resulting in direct platelet aggregation by fibrinogen

  2. Human Platelet Senescence Study.

    Science.gov (United States)

    1980-03-01

    ability to measure certain enzymes to their oxidation-reduc other enzymes which can be measured by o phosphatase , acid phosphatase , chymotryp...alkaline sin, trypsin, esterases (17)); M use of n A or wheat germ agglutinin in the second etect specific carbohydrate constituents. We have...Von Willebrand factor. Nurden and Caen also demonstrated that GPI was rich in sialic acid (5) and probably responsible for the platelets’ surface

  3. Platelet function and activation in Cavalier King Charles Spaniels with subclinical chronic valvular heart disease.

    Science.gov (United States)

    Tong, Linda J; Hosgood, Giselle L; French, Anne T; Irwin, Peter J; Shiel, Robert E

    2016-08-01

    OBJECTIVE To assess platelet closure time (CT), mean platelet component (MPC) concentration, and platelet component distribution width (PCDW) in dogs with subclinical chronic valvular heart disease. ANIMALS 89 Cavalier King Charles Spaniels (CKCSs) and 39 control dogs (not CKCSs). PROCEDURES Platelet count, MPC concentration, PCDW, and Hct were measured by use of a hematology analyzer, and CT was measured by use of a platelet function analyzer. Murmur grade and echocardiographic variables (mitral valve regurgitant jet size relative to left atrial area, left atrial-to-aortic diameter ratio, and left ventricular internal dimensions) were recorded. Associations between explanatory variables (sex, age, murmur grade, echocardiographic variables, platelet count, and Hct) and outcomes (CT, MPC concentration, and PCDW) were examined by use of multivariate regression models. RESULTS A model with 5 variables best explained variation in CT (R(2), 0.74), with > 60% of the variance of CT explained by mitral valve regurgitant jet size. The model of best fit to explain variation in MPC concentration included only platelet count (R(2), 0.24). The model of best fit to explain variation in PCDW included platelet count and sex (R(2), 0.25). CONCLUSIONS AND CLINICAL RELEVANCE In this study, a significant effect of mitral valve regurgitant jet size on CT was consistent with platelet dysfunction. However, platelet activation, as assessed on the basis of the MPC concentration and PCDW, was not a feature of subclinical chronic valvular heart disease in CKCSs.

  4. Thrombocytopenia in leptospirosis and role of platelet transfusion

    Directory of Open Access Journals (Sweden)

    Sharma Jayashree

    2007-01-01

    Full Text Available Aim : The study was designed to find out the incidence of thrombocytopenia in leptospirosis and to correlate thrombocytopenia with other parameters like renal failure, hepatic failure and bleeding manifestation like adult respiratory distress syndrome and to assess the role of platelet transfusion. Materials and Methods : 50 cases of leptospirosis during the month of July and August 2005 were retrospectively analyzed. Criteria for selection were Lepto Tek Dri - dot test positive cases of the clinically suspected cases of Leptospirosis. Degree of thrombocytopenia was categorized as severe, moderate and mild. Presence of thrombocytopenia was clinically correlated with parameters like renal dysfunction, hepatic dysfunction and hemorrhagic manifestations (mainly ARDS. Role of platelet transfusion was assessed with reference to presence and degree of thrombcytopenia and hemorrhagic manifestations. Results : Out of total 50 patients 26 were male and 24 were females. Major bleeding manifestation in the form of ARDS was seen in 15 (30% of patients. 28 (56% patients had thrombocytopenia and 22 (44% patients had normal platelet counts. Total number of patients with renal dysfunction was 24 (48%. Only four (18.18% patients with normal platelet counts had renal dysfunction while 20 (71.42% patients with thrombocytopenia had renal dysfunction. Only two (9.09% patients with normal platelet counts and 48 (46.42% patients with thrombocytopenia had hepatorenal dysfunction. Total number of patients with ARDS was 15 (30%. Of these two (13.33% had normal platelet count while 13 (86.6% patients were thrombocytopenic. Total 47 units of platelets were transfused to 12 patients in our study. Of these seven patients with severe thrombocytopenia required total 28 units, two patients with moderate thrombocytopenia required total seven units and patients with mild thrombocytopenia were transfused total 12 units of platelets. Conclusion : It is important to anticipate and

  5. Superoxide dismutase of human platelets

    International Nuclear Information System (INIS)

    Kimura, Akiro; Fujimura, Kingo; Kuramoto, Atsushi

    1979-01-01

    Superoxide dismutase (S.O.D.) is the enzyme to protect from destructive effect of superoxide (O 2 -) produced in many metabolic pathways related to oxygen. The purpose of this study was to investigate the possibility that S.O.D. may play an important role in the platelet function. The cytoplasmic and mitochondrial S.O.D. has been investigated spectrophotometrically and gel electrophoretically in human platelets from eleven patients of chronic myelogenous leukemia (CML) and three patients of primary thrombocythemia (P.Th.). Neither deficiency nor abnormality of cytoplasmic and mitochondrial S.O.D. has been found electrophoretically in any case compared to normal platelets. However, the total activity from three of the CML patients and one of the P.Th. patients were above 3 unit/mg platelet protein (normal subject: 2.11 - 2.70 unit/mg protein), suggesting the possibility either that more O 2 -production occurs in the platelets or that rather little O 2 -production due to much O 2 -deprivation by the increased S.O.D. The S.O.D. activity of human platelets has been also investigated in several conditions, where much O 2 -generation might occur in platelets. Sodium fluoride (2 mM), which increases platelet O 2 -production about 3 fold, had no effect on platelet S.O.D. The aggregated platelets induced by ADP (10 -5 M), epinephrin (50 μg/ml), ristocetin (1.5 mg/ml) or collagen (1 - 20 μg/ml) had no increase of S.O.D. activity compared to that from non aggregated platelets. X-ray irradiation (1,000 - 20,000R) had not induced its activity increase or decrease. These findings indicated the induction of platelet S.O.D. was not brought about under these conditions. (author)

  6. Overview of platelet physiology and laboratory evaluation of platelet function.

    Science.gov (United States)

    Rodgers, G M

    1999-06-01

    Appropriate laboratory testing for the platelet-type bleeding disorders hinges on an adequate assessment in the history and physical examination. Patients with histories and screening laboratory results consistent with coagulation disorders (hemophilia, disseminated intravascular coagulation) are not appropriate candidates for platelet function testing. In contrast, patients with a lifelong history of platelet-type bleeding symptoms and perhaps a positive family history of bleeding would be appropriate for testing. Figure 6 depicts one strategy to evaluate these patients. Platelet morphology can easily be evaluated to screen for two uncommon qualitative platelet disorders: Bernard-Soulier syndrome (associated with giant platelets) and gray platelet syndrome, a subtype of storage pool disorder in which platelet granulation is morphologically abnormal by light microscopy. If the bleeding disorder occurred later in life (no bleeding with surgery or trauma early in life), the focus should be on acquired disorders of platelet function. For those patients thought to have an inherited disorder, testing for vWD should be done initially because approximately 1% of the population has vWD. The complete vWD panel (factor VIII coagulant activity, vWf antigen, ristocetin cofactor activity) should be performed because many patients will have abnormalities of only one particular panel component. Patients diagnosed with vWD should be classified using multimeric analysis to identify the type 1 vWD patients likely to respond to DDAVP. If vWD studies are normal, platelet aggregation testing should be performed, ensuring that no antiplatelet medications have been ingested at least 1 week before testing. If platelet aggregation tests are normal and if suspicion for an inherited disorder remains high, vWD testing should be repeated. The evaluation of thrombocytopenia may require bone marrow examination to exclude primary hematologic disorders. If future studies with thrombopoietin assays

  7. Subpopulations in purified platelets adhering on glass.

    Science.gov (United States)

    Donati, Alessia; Gupta, Swati; Reviakine, Ilya

    2016-06-22

    Understanding how platelet activation is regulated is important in the context of cardiovascular disorders and their management with antiplatelet therapy. Recent evidence points to different platelet subpopulations performing different functions. In particular, procoagulant and aggregating subpopulations have been reported in the literature in platelets treated with the GPVI agonists. How the formation of platelet subpopulations upon activation is regulated remains unclear. Here, it is shown that procoagulant and aggregating platelet subpopulations arise spontaneously upon adhesion of purified platelets on clean glass surfaces. Calcium ionophore treatment of the adhering platelets resulted in one platelet population expressing both the procoagulant and the adherent population markers phosphatidylserine and the activated form of GPIIb/IIIa, while all of the platelets expressed CD62P independently of the ionophore treatment. Therefore, all platelets have the capacity to express all three activation markers. It is concluded that platelet subpopulations observed in various studies reflect the dynamics of the platelet activation process.

  8. Association of Adiposity Indices with Platelet Distribution Width and Mean Platelet Volume in Chinese Adults.

    Directory of Open Access Journals (Sweden)

    Jian Hou

    Full Text Available Hypoxia is a prominent characteristic of inflammatory tissue lesions. It can affect platelet function. While mean platelet volume (MPV and platelet distribution width (PDW are sample platelet indices, they may reflect subcinical platelet activation. To investigated associations between adiposity indices and platelet indices, 17327 eligible individuals (7677 males and 9650 females from the Dongfeng-Tongji Cohort Study (DFTJ-Cohort Study, n=27009 were included in this study, except for 9682 individuals with missing data on demographical, lifestyle, physical indicators and diseases relative to PDW and MPV. Associations between adiposity indices including waist circumstance (WC, waist-to-height ratio (WHtR, body mass index (BMI, and MPV or PDW in the participants were analyzed using multiple logistic regressions. There were significantly negative associations between abnormal PDW and WC or WHtR for both sexes (ptrend<0.001 for all, as well as abnormal MPV and WC or WHtR among female participants (ptrend<0.05 for all. In the highest BMI groups, only females with low MPV or PDW were at greater risk for having low MPV (OR=1.33, 95% CI=1.10, 1.62 ptrend<0.001 or PDW (OR=1.34, 95% CI=1.14, 1.58, ptrend<0.001 than those who had low MPV or PDW in the corresponding lowest BMI group. The change of PDW seems more sensitive than MPV to oxidative stress and hypoxia. Associations between reduced PDW and MPV values and WC, WHtR and BMI values in Chinese female adults may help us to further investigate early changes in human body.

  9. Influence of Oxidative Stress on Stored Platelets

    OpenAIRE

    K. Manasa; R. Vani

    2016-01-01

    Platelet storage and its availability for transfusion are limited to 5-6 days. Oxidative stress (OS) is one of the causes for reduced efficacy and shelf-life of platelets. The studies on platelet storage have focused on improving the storage conditions by altering platelet storage solutions, temperature, and materials. Nevertheless, the role of OS on platelet survival during storage is still unclear. Hence, this study was conducted to investigate the influence of storage on platelets. Platele...

  10. Platelet Concentrates: Past, Present and Future

    OpenAIRE

    Prakash, Shobha; Thakur, Aditi

    2011-01-01

    Platelets play a crucial role in hemostasis and wound healing, platelet growth factors are well known source of healing cytokines. Numerous techniques of autologous platelet concentrates have been developed and applied in oral and maxillofacial surgery. This review describes the evolution of the first and second generation of platelet concentrates (platelet rich plasma and platelet rich fibrin respectively) from their fore runner-fibrin sealants.

  11. Assessment of Platelet Profile of Healthy Volunteers in the ...

    African Journals Online (AJOL)

    ADOWIE PERE

    A similar pattern was observed for Mean Platelet Volume (MPV). However, Platelet ... Keywords: Platelet Count, Plateletcrit, Mean Platelet Volume, Platelet Distribution Width, Trimesters, ... bleeding disorders, diabetes and drugs capable of.

  12. Transient analyzer

    International Nuclear Information System (INIS)

    Muir, M.D.

    1975-01-01

    The design and design philosophy of a high performance, extremely versatile transient analyzer is described. This sub-system was designed to be controlled through the data acquisition computer system which allows hands off operation. Thus it may be placed on the experiment side of the high voltage safety break between the experimental device and the control room. This analyzer provides control features which are extremely useful for data acquisition from PPPL diagnostics. These include dynamic sample rate changing, which may be intermixed with multiple post trigger operations with variable length blocks using normal, peak to peak or integrate modes. Included in the discussion are general remarks on the advantages of adding intelligence to transient analyzers, a detailed description of the characteristics of the PPPL transient analyzer, a description of the hardware, firmware, control language and operation of the PPPL transient analyzer, and general remarks on future trends in this type of instrumentation both at PPPL and in general

  13. Simultaneous Description of Activity Coefficients and Solubility with eCPA

    DEFF Research Database (Denmark)

    Schlaikjer, Anders; Thomsen, Kaj; Kontogeorgis, Georgios

    2017-01-01

    with salt specific parameters. The focus is on accurate description of the salt solubility, and low deviation correlations are obtained for all salts investigated. The inclusion of the solubility data in the parametrization has, compared to parameters only parametrized to osmotic coefficients and activity...... coefficients, not significantly affected the deviations of the osmotic coefficients and activity coefficients. The average deviations of the activity coefficient does increase slightly and it was found that the increase in deviations was almost entirely due to reduced accuracy at high temperature and high...... molality. The model is, furthermore, compared to the activity coefficient model, Extended UNIQUAC. It is shown that the eCPA provides more accurate solubility description at higher temperatures than Extended UNIQUAC but also that Extended UNIQUAC is slightly better at describing the activity coefficients...

  14. Phase equilibria modeling of methanol-containing systems with the CPA and sPC-SAFT equations of state

    DEFF Research Database (Denmark)

    Tybjerg, Peter Chr. V.; Kontogeorgis, Georgios; Michelsen, Michael Locht

    2010-01-01

    Proper representation at various conditions of phase equilibria of methanol-containing mixtures (with hydrocarbons, water, etc.) is Important for oil flow assurance purposes In this work two association equations of state. CPA and sPC-SAFT, are applied to methanol-containing mixtures The purpose ...

  15. Modeling phase equilibria for acid gas mixtures using the CPA equation of state. Part II: Binary mixtures with CO2

    DEFF Research Database (Denmark)

    Tsivintzelis, Ioannis; Kontogeorgis, Georgios; Michelsen, Michael Locht

    2011-01-01

    In Part I of this series of articles, the study of H2S mixtures has been presented with CPA. In this study the phase behavior of CO2 containing mixtures is modeled. Binary mixtures with water, alcohols, glycols and hydrocarbons are investigated. Both phase equilibria (vapor–liquid and liquid–liqu...

  16. Ten years with the CPA (Cubic-Plus-Association) equation of state. Part 2. Cross-associating and multicomponent systems

    DEFF Research Database (Denmark)

    Kontogeorgis, Georgios; Michelsen, Michael Locht; Folas, Georgios

    2006-01-01

    In this second article of the review on the applications of the CPA (Cubic-Plus-Association) equation of state, the focus is placed on cross-associating systems. Various such mixtures are investigated, including (i) systems with two self-associating compounds ( e. g., water-alcohol systems...

  17. Modeling vapor-liquid interfaces with the gradient theory in combination with the CPA equation of state

    DEFF Research Database (Denmark)

    Queimada, Antonio; Miqueu, C; Marrucho, IM

    2005-01-01

    and the correct phase equilibrium of water + hydrocarbon systems already obtained from CPA. In this work, preliminary studies involving the vapor-liquid interfacial tensions of some selected associating and non-associating pure components (water, ethanol, n-butane, n-pentane, n-hexane, n-heptane) are presented...

  18. Online versus Face-to-Face Accounting Education: A Comparison of CPA Exam Outcomes across Matched Institutions

    Science.gov (United States)

    Morgan, John Daniel

    2015-01-01

    Programmatic-level comparisons are made between the certified public accountant (CPA) exam outcomes of two types of accounting programs: online or distance accounting programs and face-to-face or classroom accounting programs. After matching programs from each group on student selectivity at admission, the two types of programs are compared on CPA…

  19. 78 FR 9731 - Gulf of Mexico, Outer Continental Shelf (OCS), Central Planning Area (CPA) Oil and Gas Lease Sale...

    Science.gov (United States)

    2013-02-11

    ... Environmental Impact Statement (Multisale FEIS). Authority: This NOA is published pursuant to the regulations... the NEPA process. The Multisale FEIS evaluated the environmental and socioeconomic impacts for CPA... DEPARTMENT OF THE INTERIOR Bureau of Ocean Energy Management Gulf of Mexico, Outer Continental...

  20. Evaluation of amotosalem treated platelets over 7 days of storage with an automated cytometry assay panel.

    Science.gov (United States)

    Diquattro, M; De Francisci, G; Bonaccorso, R; Tagliavia, A M; Marcatti, M; Palma, B; Agliastro, R

    2013-12-01

    Pathogen Inactivation allows to overcome microbial contamination and growth related to storage of platelets concentrates (PC) at room temperature. The aim of our study was to evaluate the platelet storage lesion extending the storage period of pathogen inactivated platelet concentrates over 7 days using an automated cytometry assay panel. We analyzed 43 concentrates subjected to pathogen inactivation (CPPI) at 3, 5 and 7 days evaluating: platelet count, mean platelet volume, platelets at low optical density, platelets at high density, GPIIb-IIIa glycoprotein, platelet microparticles, lactate dehydrogenase. The collection bags (Fenwal) and the IBS kit made in PL2410/PL2411 are approved for the conservation of PC up to 7 days. Data analysis was performed with anova test. All the parameters except small platelets and PMP were statistically different among day 7 vs. 3 and day 7 vs. 5. Our study showed a progressive modification of pathogen inactivated platelet concentrates observed up to 7 days. The persistence of the secretory pool and the presence of the platelet membrane fibrinogen receptor suggest the persistence of a potential hemostatic efficacy. Clinical studies are necessary to directly correlate this type of analysis to 24 h recovery or survival of transfused platelets in humans. © 2013 John Wiley & Sons Ltd.

  1. The role of platelet and endothelial GARP in thrombosis and hemostasis.

    Science.gov (United States)

    Vermeersch, Elien; Denorme, Frederik; Maes, Wim; De Meyer, Simon F; Vanhoorelbeke, Karen; Edwards, Justin; Shevach, Ethan M; Unutmaz, Derya; Fujii, Hodaka; Deckmyn, Hans; Tersteeg, Claudia

    2017-01-01

    Glycoprotein-A Repetitions Predominant protein (GARP or LRRC32) is present on among others human platelets and endothelial cells. Evidence for its involvement in thrombus formation was suggested by full knockout of GARP in zebrafish. To evaluate the role of GARP in platelet physiology and in thrombus formation using platelet and endothelial conditional GARP knock out mice. Platelet and endothelial specific GARP knockout mice were generated using the Cre-loxP recombination system. The function of platelets without GARP was measured by flow cytometry, spreading analysis and aggregometry using PAR4-activating peptide and collagen related peptide. Additionally, clot retraction and collagen-induced platelet adhesion and aggregation under flow were analyzed. Finally, in vivo tail bleeding time, occlusion time of the mesenteric and carotid artery after FeCl3-induced thrombosis were determined in platelet and endothelial specific GARP knock out mice. Platelet specific GARP knockout mice had normal surface GPIb, GPVI and integrin αIIb glycoprotein expression. Although GARP expression was increased upon platelet activation, platelets without GARP displayed normal agonist induced activation, spreading on fibrinogen and aggregation responses. Furthermore, absence of GARP on platelets did not influence clot retraction and had no impact on thrombus formation on collagen-coated surfaces under flow. In line with this, neither the tail bleeding time nor the occlusion time in the carotid- and mesenteric artery after FeCl3-induced thrombus formation in platelet or endothelial specific GARP knock out mice were affected. Evidence is provided that platelet and endothelial GARP are not important in hemostasis and thrombosis in mice.

  2. The role of platelet and endothelial GARP in thrombosis and hemostasis.

    Directory of Open Access Journals (Sweden)

    Elien Vermeersch

    Full Text Available Glycoprotein-A Repetitions Predominant protein (GARP or LRRC32 is present on among others human platelets and endothelial cells. Evidence for its involvement in thrombus formation was suggested by full knockout of GARP in zebrafish.To evaluate the role of GARP in platelet physiology and in thrombus formation using platelet and endothelial conditional GARP knock out mice.Platelet and endothelial specific GARP knockout mice were generated using the Cre-loxP recombination system. The function of platelets without GARP was measured by flow cytometry, spreading analysis and aggregometry using PAR4-activating peptide and collagen related peptide. Additionally, clot retraction and collagen-induced platelet adhesion and aggregation under flow were analyzed. Finally, in vivo tail bleeding time, occlusion time of the mesenteric and carotid artery after FeCl3-induced thrombosis were determined in platelet and endothelial specific GARP knock out mice.Platelet specific GARP knockout mice had normal surface GPIb, GPVI and integrin αIIb glycoprotein expression. Although GARP expression was increased upon platelet activation, platelets without GARP displayed normal agonist induced activation, spreading on fibrinogen and aggregation responses. Furthermore, absence of GARP on platelets did not influence clot retraction and had no impact on thrombus formation on collagen-coated surfaces under flow. In line with this, neither the tail bleeding time nor the occlusion time in the carotid- and mesenteric artery after FeCl3-induced thrombus formation in platelet or endothelial specific GARP knock out mice were affected.Evidence is provided that platelet and endothelial GARP are not important in hemostasis and thrombosis in mice.

  3. Platelet activation during preparation of platelet concentrates: a comparison of the platelet-rich plasma and the buffy coat methods

    NARCIS (Netherlands)

    Fijnheer, R.; Pietersz, R. N.; de Korte, D.; Gouwerok, C. W.; Dekker, W. J.; Reesink, H. W.; Roos, D.

    1990-01-01

    The activation of platelets during the preparation of platelet concentrates (PCs) by two methods was compared. To eliminate interdonor differences, 2 units of whole blood were pooled and subsequently divided into two batches. From one batch, the platelets were harvested as pelleted platelets from

  4. Mean platelet volume and mean platelet volume/platelet count ratio

    African Journals Online (AJOL)

    Amira M. Elsayed

    2016-03-30

    Mar 30, 2016 ... The aim of this study was to compare the MPV and mean platelet volume/platelet count ... brain stroke, both in the acute phase and long after disease.17 ... males, while the healthy controls comprised 12 females and 8.

  5. Platelet biomechanics, platelet bioenergetics, and applications to clinical practice and translational research.

    Science.gov (United States)

    George, Mitchell J; Bynum, James; Nair, Prajeeda; Cap, Andrew P; Wade, Charles E; Cox, Charles S; Gill, Brijesh S

    2018-07-01

    The purpose of this review is to explore the relationship between platelet bioenergetics and biomechanics and how this relationship affects the clinical interpretation of platelet function devices. Recent experimental and technological advances highlight platelet bioenergetics and biomechanics as alternative avenues for collecting clinically relevant data. Platelet bioenergetics drive energy production for key biomechanical processes like adhesion, spreading, aggregation, and contraction. Platelet function devices like thromboelastography, thromboelastometry, and aggregometry measure these biomechanical processes. Platelet storage, stroke, sepsis, trauma, or the activity of antiplatelet drugs alters measures of platelet function. However, the specific mechanisms governing these alterations in platelet function and how they relate to platelet bioenergetics are still under investigation.

  6. Effects of platelet-poor plasma, platelet-rich plasma, and platelet-rich fibrin on healing of extraction sockets with buccal dehiscence in dogs.

    Science.gov (United States)

    Hatakeyama, Ichiro; Marukawa, Eriko; Takahashi, Yukinobu; Omura, Ken

    2014-02-01

    Alveolar bone resorption generally occurs during healing after tooth extraction. This study aimed to evaluate the effects of platelet-poor plasma (PPP), platelet-rich plasma (PRP), and platelet-rich fibrin (PRF) on healing in a ridge-augmentation model of the canine socket with dehiscence of the buccal wall. The third mandibular premolars of 12 beagle dogs were extracted and a 3 mm buccal dehiscence from the alveolar crest to the buccal wall of the extraction socket was created. These sockets were then divided into four groups on the basis of the material used to fill the sockets: PPP, PRP, PRF, and control (no graft material) groups. Results were evaluated at 4 and 8 weeks after surgery. The ultrastructural morphology and constructs of each blood product were studied by a scanning electron microscope (SEM) or calculating concentrations of platelets, fibrinogen, platelet-derived growth factor, and transforming growth factor-β. A total of five microcomputed tomography images of specimens were selected for measurement, and the area occupied by the newly formed bone as well as the horizontal bone width were measured. Moreover, decalcified tissue specimens from each defect were analyzed histologically. The median area of new bone at 4 and 8 weeks and median horizontal bone width at 8 weeks were the highest in the PPP group. However, bone maturation in the PRF and the PRP groups was more progressed than that in the PPP and control groups. By SEM findings, the PRF group showed a more highly condensed fibrin fiber network that was regularly arranged when compared with the PPP and PRP groups. The growth factors released from platelets in PRP indicated higher concentrations than that in PRF. Under more severe conditions for bone formation, as in this experiment, the growth factors released from platelets had a negative effect on bone formation. This study showed that PPP is an effective material for the preservation of sockets with buccal dehiscence.

  7. Quality of harvested autologous platelets compared with stored donor platelets for use after cardiopulmonary bypass procedures.

    Science.gov (United States)

    Crowther, M; Ford, I; Jeffrey, R R; Urbaniak, S J; Greaves, M

    2000-10-01

    Platelet dysfunction has a major contribution in bleeding after cardiopulmonary bypass (CPB) and transfusion of platelets is frequently used to secure haemostasis. Allogeneic platelets prepared for transfusion are functionally impaired. Autologous platelets harvested preoperatively require a shorter storage time before transfusion and their use also avoids the risks associated with transfusion of allogeneic blood products. For the first time, we have compared the functional quality of autologous platelets with allogeneic platelets prepared by two methods, immediately before infusion. Platelet activation was assessed by P-selectin expression and fibrinogen binding using flow cytometry. We also monitored the effects of CPB surgery and re-infusion of autologous platelets on platelet function. Autologous platelet-rich plasma (PRP) contained a significantly lower (P platelets compared with allogeneic platelet preparations, and also contained a significantly higher (P platelets. Allogeneic platelets prepared by donor apheresis were more activated and less responsive than those produced by centrifugation of whole blood. In patients' blood, the percentage of platelets expressing P-selectin or binding fibrinogen increased significantly after CPB (P platelets responsive to in vitro agonists was decreased (P platelet activation during the procedure. The percentage of activated platelets decreased (statistically not significant) after re-infusion of autologous PRP. P-selectin expression had returned to pre-CPB levels 24 h post-operatively. Autologous platelet preparations display minimal activation, but remain responsive. Conservation of platelet function may contribute to the potential clinical benefits of autologous transfusion in cardiopulmonary bypass.

  8. Radioimmune assay of human platelet prostaglandin synthetase

    International Nuclear Information System (INIS)

    Roth, G.J.; Machuga, E.T.

    1982-01-01

    Normal platelet function depends, in part, on platelet PG synthesis. PG synthetase (cyclo-oxygenase) catalyzes the first step in PG synthesis, the formation of PGH 2 from arachidonic acid. Inhibition of the enzyme by ASA results in an abnormality in the platelet release reaction. Patients with pparent congenital abnormalities in the enzyme have been described, and the effects have been referred to as ''aspirin-like'' defects of the platelet function. These patients lack platelet PG synthetase activity, but the actual content of PG synthetase protein in these individuals' platelets is unknown. Therefore an RIA for human platelet PG synthetase would provide new information, useful in assessing the aspirin-like defects of platelet function. An RIA for human platelet PG synthetase is described. The assay utilizes a rabbit antibody directed against the enzyme and [ 125 I]-labelled sheep PG synthetase as antigen. The human platelet enzyme is assayed by its ability to inhibit precipitation of the [ 125 I]antigen. The assay is sensitive to 1 ng of enzyme. By the immune assay, human platelets contain approximately 1200 ng of PG synethetase protein per 1.5 mg of platelet protein (approximately 10 9 platelets). This content corresponds to 10,000 enzyme molecules per platelet. The assay provides a rapid and convenient assay for the human platelet enzyme, and it can be applied to the assessment of patients with apparent platelet PG synthetase (cyclo-oxygenase) deficiency

  9. Platelet Glycoprotein Ib-IX and Malignancy

    Science.gov (United States)

    2010-09-01

    provide a unique microenvironment supporting the accumulation of more platelets and the elaboration of a fibrin - rich network produced by coagulation...process and can initiate the formation of a platelet - rich thrombus by tethering the platelet to a thrombogenic surface. Several ligands binding to GP Ib... Platelet Glycoprotein Ib-IX and Malignancy PRINCIPAL INVESTIGATOR: Jerry Ware, Ph.D

  10. Platelet-derived-growth-factor-induced signalling in human platelets: phosphoinositide-3-kinase-dependent inhibition of platelet activation.

    Science.gov (United States)

    Selheim, F; Fukami, M H; Holmsen, H; Vassbotn, F S

    2000-09-01

    Human platelets release platelet-derived growth factor (PDGF) from alpha-granules during platelet activation. We have previously shown that platelets have PDGF alpha-receptors, a transmembrane tyrosine kinase that takes part in negative feedback regulation during platelet activation. Here we have described a study of PDGF-induced tyrosine phosphorylation of platelet substrates and phosphoinositide 3-kinase (PI-3K) activity in collagen-stimulated platelets. By immunoblotting with phosphotyrosine antibodies of collagen-activated platelets we found that PDGF increased the phosphorylation of several platelet substrates, e.g. pp140, pp120 and pp85. PDGF inhibited collagen-induced platelet activation in the presence of inhibitors of autocrine stimulation, thus blocking the pure collagen-induced signal transduction. PDGF enhanced the collagen-induced formation of PtdIns(3,4)P(2) and PtdIns(3,4,5)P(3) as measured by HPLC. Wortmannin and LY294002, two unrelated inhibitors of PI-3K, were used to investigate the role of PI-3K in PDGF-induced platelet signalling. Incubation of platelets with wortmannin and LY294002 blocked the formation of three phosphorylated inositides as well as the inhibitory effect of PDGF on collagen-induced platelet activation. We conclude that the inhibitory effect of PDGF on platelet activation is PI-3K dependent. This is the first demonstration of a negative regulatory function of 3-phosphorylated inositides in platelets.

  11. Radiometric analyzer

    International Nuclear Information System (INIS)

    Arima, S.; Oda, M.; Miyashita, K.; Takada, M.

    1977-01-01

    A radiometric analyzer for measuring the characteristic values of a sample by radiation includes a humer of radiation measuring subsystems having different ratios of sensitivities to the elements of the sample and linearizing circuits having inverse function characteristics of calibration functions which correspond to the radiation measuring subsystems. A weighing adder operates a desirable linear combination of the outputs of the linearizing circuits. Operators for operating between two or more different linear combinations are included

  12. Prophylactic platelets in dengue

    DEFF Research Database (Denmark)

    Whitehorn, James; Rodriguez Roche, Rosmari; Guzman, Maria G

    2012-01-01

    Dengue is the most important arboviral infection of humans. Thrombocytopenia is frequently observed in the course of infection and haemorrhage may occur in severe disease. The degree of thrombocytopenia correlates with the severity of infection, and may contribute to the risk of haemorrhage...... of platelets in dengue. Respondents were all physicians involved with the treatment of patients with dengue. Respondents were asked that their answers reflected what they would do if they were the treating physician. We received responses from 306 physicians from 20 different countries. The heterogeneity...... of the responses highlights the variation in clinical practice and lack of an evidence base in this area and underscores the importance of prospective clinical trials to address this key question in the clinical management of patients with dengue....

  13. Electrolyte CPA equation of state for very high temperature and pressure reservoir and basin applications

    Science.gov (United States)

    Courtial, Xavier; Ferrando, Nicolas; de Hemptinne, Jean-Charles; Mougin, Pascal

    2014-10-01

    In this work, an electrolyte version of the Cubic Plus Association (eCPA) equation of state has been adapted to systems containing CH4, CO2, H2O and NaCl (up to 5 molal) at pressures up to 200 MPa and temperatures up to 773 K for salt-free systems and 573 K for salt-containing systems. Its purpose is to represent the phase behavior (including salting-out effect and critical point) and the phase densities in a range of temperature and pressure encountered in deep reservoirs and basins. The goal of the parameterization proposed is not to reach a very high accuracy for phase equilibrium and volumetric properties, but rather to develop a semi-predictive approach to model the phase and volumetric behavior of this system while allowing an easy extension to other compounds. Without salt, predictions for pure component vapor pressures and liquid molar volumes present an average absolute deviation (AAD) lower than 3% compared to experimental reference values. The pure component molar volumes out of saturation show an AAD lower than 4%. The highest deviations in densities are observed as expected in the vicinity of the critical coordinates of pure water and this effect increases when gases or salts are added to the system. For each binary system, CH4 + CO2, CH4 + H2O and CO2 + H2O, binary interaction parameters have been fitted to correctly represent the shape of the fluid phase envelopes (including all critical points) in the entire temperature and pressure range considered (219 K to 633 K and up to 250 MPa). The methane concentration in both phases of the CH4 + CO2 binary system is represented with an AAD lower than 9%. The methane solubility in water is represented within 16% and 8% for the methane content of the vapor. The CO2 solubility in water is within 26%, while the CO2 in the vapor phase shows an average deviation of 12%. All molar volumes are represented with an AAD lower than 3%. The few VLE experimental data for the CH4 + CO2 + H2O ternary system are fairly well

  14. First comparative analysis concerning the plasma platelet contamination during MNC collection.

    Science.gov (United States)

    Pfeiffer, Hella; Achenbach, Susanne; Strobel, Julian; Zimmermann, Robert; Eckstein, Reinhold; Strasser, Erwin F

    2017-08-01

    Monocytes can be cultured into dendritic cells with addition of autologous plasma, which is highly prone to platelet contamination due to the apheresis process. Since platelets affect the maturation process of monocytes into dendritic cells and might even lead to a diminished harvest of dendritic cells, it is very important to reduce the platelet contamination. A new collection device (Spectra Optia) was analyzed, compared to two established devices (COM.TEC, Cobe Spectra) and evaluated regarding the potential generation of source plasma. Concurrent plasma collected during leukapheresis was analyzed for residual cell contamination in a prospective study with the new Spectra Optia apheresis device (n=24) and was compared with COM.TEC and Cobe Spectra data (retrospective analysis, n=72). Donor pre-donation counts of platelets were analyzed for their predictive value of contaminating PLTs in plasma harvests. The newest apheresis device showed the lowest residual platelet count of the collected concurrent plasma (median 3.50×10 9 /l) independent of pre-donation counts. The other two devices and sets had a higher platelet contamination. The contamination of the plasma with leukocytes was very low (only 2.0% were higher than 0.5×10 9 /l). This study showed a significant reduction of platelet contamination of the concurrent plasma collected with the new Spectra Optia device. This plasma product with low residual platelets and leukocytes might also be used as plasma for fractionation. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Influence of caffeine on blood pressure and platelet aggregation

    Directory of Open Access Journals (Sweden)

    José Wilson S. Cavalcante

    2000-08-01

    Full Text Available OBJECTIVE: Studies have demonstrated that methylxanthines, such as caffeine, are A1 and A2 adenosine receptor antagonists found in the brain, heart, lungs, peripheral vessels, and platelets. Considering the high consumption of products with caffeine in their composition, in Brazil and throughout the rest of the world, the authors proposed to observe the effects of this substance on blood pressure and platelet aggregation. METHODS: Thirteen young adults, ranging from 21 to 27 years of age, participated in this study. Each individual took 750mg/day of caffeine (250mg tid, over a period of seven days. The effects on blood pressure were analyzed through the pressor test with handgrip, and platelet aggregation was analyzed using adenosine diphosphate, collagen, and adrenaline. RESULTS: Diastolic pressure showed a significant increase 24 hours after the first intake (p<0.05. This effect, however, disappeared in the subsequent days. The platelet aggregation tests did not reveal statistically significant alterations, at any time during the study. CONCLUSION: The data suggest that caffeine increases diastolic blood pressure at the beginning of caffeine intake. This hypertensive effect disappears with chronic use. The absence of alterations in platelet aggregation indicates the need for larger randomized studies.

  16. Apheresis platelet concentrates contain platelet-derived and endothelial cell-derived microparticles

    NARCIS (Netherlands)

    Rank, A.; Nieuwland, R.; Liebhardt, S.; Iberer, M.; Grützner, S.; Toth, B.; Pihusch, R.

    2011-01-01

    Background and Objectives Microparticles (MP) are membrane vesicles with thrombogenic and immunomodulatory properties. We determined MP subgroups from resting platelets, activated platelets and endothelial cells in donors and apheresis platelet concentrates (PC). Material and Methods MP were double

  17. Contamination Analyzer

    Science.gov (United States)

    1994-01-01

    Measurement of the total organic carbon content in water is important in assessing contamination levels in high purity water for power generation, pharmaceutical production and electronics manufacture. Even trace levels of organic compounds can cause defects in manufactured products. The Sievers Model 800 Total Organic Carbon (TOC) Analyzer, based on technology developed for the Space Station, uses a strong chemical oxidizing agent and ultraviolet light to convert organic compounds in water to carbon dioxide. After ionizing the carbon dioxide, the amount of ions is determined by measuring the conductivity of the deionized water. The new technique is highly sensitive, does not require compressed gas, and maintenance is minimal.

  18. Characterization of platelet adhesion under flow using microscopic image sequence analysis.

    Science.gov (United States)

    Machin, M; Santomaso, A; Cozzi, M R; Battiston, M; Mazzuccato, M; De Marco, L; Canu, P

    2005-07-01

    A method for quantitative analysis of platelet deposition under flow is discussed here. The model system is based upon perfusion of blood platelets over an adhesive substrate immobilized on a glass coverslip acting as the lower surface of a rectangular flow chamber. The perfusion apparatus is mounted onto an inverted microscope equipped with epifluorescent illumination and intensified CCD video camera. Characterization is based on information obtained from a specific image analysis method applied to continuous sequences of microscopical images. Platelet recognition across the sequence of images is based on a time-dependent, bidimensional, gaussian-like pdf. Once a platelet is located,the variation of its position and shape as a function of time (i.e., the platelet history) can be determined. Analyzing the history we can establish if the platelet is moving on the surface, the frequency of this movement and the distance traveled before its resumes the velocity of a non-interacting cell. Therefore, we can determine how long the adhesion would last which is correlated to the resistance of the platelet-substrate bond. This algorithm enables the dynamic quantification of trajectories, as well as residence times, arrest and release frequencies for a high numbers of platelets at the same time. Statistically significant conclusions on platelet-surface interactions can then be obtained. An image analysis tool of this kind can dramatically help the investigation and characterization of the thrombogenic properties of artificial surfaces such as those used in artificial organs and biomedical devices.

  19. Evaluation of single and double centrifugation tube methods for concentrating equine platelets.

    Science.gov (United States)

    Argüelles, D; Carmona, J U; Pastor, J; Iborra, A; Viñals, L; Martínez, P; Bach, E; Prades, M

    2006-10-01

    The aim of this study was to evaluate single and double centrifugation tube methods for concentrating equine platelets. Whole blood samples were collected from clinically normal horses and processed by use of single and double centrifugation tube methods to obtain four platelet concentrates (PCs): PC-A, PC-B, PC-C, and PC-D, which were analyzed using a flow cytometry hematology system for hemogram and additional platelet parameters (mean platelet volume, platelet distribution width, mean platelet component concentration, mean platelet component distribution width). Concentrations of transforming growth factor beta 1 (TGF-beta(1)) were determined in all the samples. Platelet concentrations for PC-A, PC-B, PC-C, and PC-D were 45%, 44%, 71%, and 21% higher, respectively, compared to the same values for citrated whole blood samples. TGF-beta(1) concentrations for PC-A, PC-B, PC-C, and PC-D were 38%, 44%, 44%, and 37% higher, respectively, compared to citrated whole blood sample values. In conclusion, the single and double centrifugation tube methods are reliable methods for concentrating equine platelets and for obtaining potentially therapeutic TGF-beta(1) levels.

  20. Accurate measurement of volume and shape of resting and activated blood platelets from light scattering.

    Science.gov (United States)

    Moskalensky, Alexander E; Yurkin, Maxim A; Konokhova, Anastasiya I; Strokotov, Dmitry I; Nekrasov, Vyacheslav M; Chernyshev, Andrei V; Tsvetovskaya, Galina A; Chikova, Elena D; Maltsev, Valeri P

    2013-01-01

    We introduce a novel approach for determination of volume and shape of individual blood platelets modeled as an oblate spheroid from angle-resolved light scattering with flow-cytometric technique. The light-scattering profiles (LSPs) of individual platelets were measured with the scanning flow cytometer and the platelet characteristics were determined from the solution of the inverse light-scattering problem using the precomputed database of theoretical LSPs. We revealed a phenomenon of parameter compensation, which is partly explained in the framework of anomalous diffraction approximation. To overcome this problem, additional a priori information on the platelet refractive index was used. It allowed us to determine the size of each platelet with subdiffraction precision and independent of the particular value of the platelet aspect ratio. The shape (spheroidal aspect ratio) distributions of platelets showed substantial differences between native and activated by 10 μM adenosine diphosphate samples. We expect that the new approach may find use in hematological analyzers for accurate measurement of platelet volume distribution and for determination of the platelet activation efficiency.

  1. Platelet lysate obtained via plateletpheresis performed in standing and awake equine donors.

    Science.gov (United States)

    Sumner, Scarlett M; Naskou, Maria C; Thoresen, Merrilee; Copland, Ian; Peroni, John F

    2017-07-01

    Platelet preparations containing growth factors, attachment factors, and enzymes are appealing to enhance healing of injured tissues and as an alternative to xenogenic serum in cell culture media. Plateletpheresis is commonly used to collect platelets in human medicine but has not been validated in horses. Plateletpheresis to collect platelet concentrate was performed on six female, mixed breed, chemically restrained horses using commercially available apheresis equipment. Before and immediately after plateletpheresis, we performed physical examinations and collected blood for chemistry and coagulation panels and then again at 8, 16, 24, and 48 hours after the procedure. To produce platelet lysate, the platelet concentrate underwent two freeze-thaw cycles followed by centrifugation and filtration processing. The platelet lysate was then analyzed for cellular debris, fibrinogen, and growth factors. The collected platelet concentration contained a mean platelet yield of 390 × 10 3 /μL. Donor platelet count decreased from a mean of 193 × 10 3 /μL to 138 × 10 3 /μL after plateletpheresis, but no individual was at risk for hemorrhage. Pooled platelet lysate had minimal cellular residue and contained growth factor concentrations at 6.1 ng/mL for transforming growth factor-β1, at 3.5 ng/mL for platelet-derived growth factor-BB, and at 13.8 ng/mL for vascular endothelial growth factor-A. Plateletpheresis using commercially available apheresis equipment is a feasible option for collecting platelet concentrate from equine donors. The lysate generated from the apheresis product contains growth factors and has potential to be used as a fetal bovine serum substitute for cell culture. © 2017 AABB.

  2. Application of the cubic-plus-association (CPA) equation of state to complex mixtures with aromatic hydrocarbons

    DEFF Research Database (Denmark)

    Folas, Georgios; Kontogeorgis, Georgios; Michelsen, Michael Locht

    2006-01-01

    The cubic-plus-association (CPA) equation of state is applied to phase equilibria of mixtures containing alcohols, glycols, water, and aromatic or olefinic hydrocarbons. Previously, CPA has been successfully used for mixtures containing various associating compounds (alcohols, glycols, amines......, organic acids, and water) and aliphatic hydrocarbons. We show in this work that the model can be satisfactorily extended to complex vapor-liquid-liquid equilibria with aromatic or olefinic hydrocarbons. The solvation between aromatics/olefinics and polar compounds is accounted for. This is particularly...... important for mixtures containing water and glycols, but less so for mixtures with alcohols. For water/hydrocarbons, a single binary interaction parameter which accounts for the solvation is fitted to the experimental liquid-liquid equilibria (LLE) data. The interaction parameter of the physical term...

  3. Equation of state modelling of systems with ionic liquids: Literature review and application with the Cubic Plus Association (CPA) model

    DEFF Research Database (Denmark)

    Maia, Filipa Meireles; Tsivintzelis, Ioannis; Rodriguez, Oscar

    2012-01-01

    For the last decade ionic liquids have been regarded as compounds of interest by the academic and industrial communities. These compounds present several advantages when compared to other typical solvents. However, because of their novelty, a deep understanding of their phase behaviour and their ......For the last decade ionic liquids have been regarded as compounds of interest by the academic and industrial communities. These compounds present several advantages when compared to other typical solvents. However, because of their novelty, a deep understanding of their phase behaviour...... and their interactions with other components is still needed. In this work, we made a review of literature studies on modelling systems with ionic liquids using equation of state models. Furthermore, we applied the Cubic Plus Association (CPA) equation of state to describe the phase behaviour of two ionic liquids, 1...... is in progress for improving the modelling of LLE with the CPA equation of state....

  4. In vitro function of random donor platelets stored for 7 days in composol platelet additive solution

    Directory of Open Access Journals (Sweden)

    Gupta Ashish

    2011-01-01

    Full Text Available Background and Aim: Platelets are routinely isolated from whole blood and stored in plasma for 5 days. The present study was done to assess the in vitro function of random donor platelets stored for 7 days in composol platelet additive solution at 22°C. Materials and Methods: The study sample included 30 blood donors of both sex in State Blood Bank, CSM Medical University, Lucknow. Random donor platelets were prepared by platelet rich plasma method. Whole blood (350 ml was collected in anticoagulant Citrate Phosphate Dextrose Adenine triple blood bags. Random donor platelets were stored for 7 days at 22°C in platelet incubators and agitators, with and without additive solution. Results: Platelet swirling was present in all the units at 22°C on day 7, with no evidence of bacterial contamination. Comparison of the mean values of platelet count, platelet factor 3, lactate dehydrogenase, pH, glucose and platelet aggregation showed no significant difference in additive solution, whereas platelet factor 3, glucose and platelet aggregation showed significant difference (P < 0.001 on day 7 without additive solution at 22°C. Conclusion: Our study infers that platelet viability and aggregation were best maintained within normal levels on day 7 of storage in platelet additive solution at 22°C. Thus, we may conclude that in vitro storage of random donor platelets with an extended shelf life of 7 days using platelet additive solution may be advocated to improve the inventory of platelets.

  5. Platelet-derived growth factor inhibits platelet activation in heparinized whole blood.

    Science.gov (United States)

    Selheim, F; Holmsen, H; Vassbotn, F S

    1999-08-15

    We previously have demonstrated that human platelets have functionally active platelet-derived growth factor alpha-receptors. Studies with gel-filtered platelets showed that an autocrine inhibition pathway is transduced through this tyrosine kinase receptor during platelet activation. The physiological significance of this inhibitory effect of platelet-derived growth factor on gel-filtered platelets activation is, however, not known. In the present study, we investigated whether platelet-derived growth factor inhibits platelet activation under more physiological conditions in heparinized whole blood, which represents a more physiological condition than gel-filtered platelets. Using flow cytometric assays, we demonstrate here that platelet-derived growth factor inhibits thrombin-, thrombin receptor agonist peptide SFLLRN-, and collagen-induced platelet aggregation and shedding of platelet-derived microparticles from the platelet plasma membrane during platelet aggregation in stirred heparinized whole blood. The inhibitory effect of platelet-derived growth factor was dose dependent. However, under nonaggregating conditions (no stirring), we could not demonstrate any significant effect of platelet-derived growth factor on thrombin- and thrombin receptor agonist peptide-induced platelet surface expression of P-selectin. Our results demonstrate that platelet-derived growth factor appears to be a true antithrombotic agent only under aggregating conditions in heparinized whole blood.

  6. Platelet adhesiveness: the effect of centrifugation on the measurement of adhesiveness in platelet-rich plasma

    Science.gov (United States)

    McBride, J. A.

    1968-01-01

    Platelet adhesiveness has been measured in citrated whole blood and in platelet-rich plasma obtained from normal subjects, splenectomized patients, and from patients in whom the diagnosis of recurrent venous thrombosis had been made. The duration of centrifugation used in the preparation of platelet-rich plasma was found to have a profound effect on the measurement of platelet adhesiveness because the figure for platelet adhesiveness measured in platelet-rich plasma obtained by centrifugation was considerably lower than that found in citrated whole blood. This effect was particularly marked when platelet-rich plasma was obtained from subjects in whom platelet adhesiveness measured in whole blood was increased. PMID:5699080

  7. CPA theory of the magnetization in rare earth transition metal alloys

    International Nuclear Information System (INIS)

    Szpunar, B.; Lindgaard, P.A.

    1976-11-01

    Calculations were made of the magnetic moment per atom of the transition metal and the rare earth metal in the intermetallic compounds, Gdsub(1-x)Nisub(x), Gdsub(1-x)Fesub(x), Gdsub(1-x)Cosub(x), and Ysub(1-x)Cosub(x). A simple model of the disordered alloy consisting of spins localized on the rare earth atoms and interacting with a narrow d-band is considered. The magnetic moment of the alloy at zero temperature is calculated within the molecular field and Hartree-Fock approximations. Disorder is treated in the coherent potential approximation. Results are in good agreement with the experimental data obtained for the crystalline and amorphous intermetallic compounds. It is shown that the temperature dependence of the magnetic moments and Curie and ferrimagnetic compensation temperatures can be accounted for by a simple model assuming a RKKY interaction between the rare-earth moments and the transition metal pseudo spin. The interaction is mediated by an effective alloy medium calculated using the CPA theory and elliptic densities of states. (Auth.)

  8. Solid–liquid equilibria for binary and ternary systems with the Cubic-Plus-Association (CPA) equation of state

    DEFF Research Database (Denmark)

    Fettouhi, André; Thomsen, Kaj

    2010-01-01

    A systematic investigation of the CPA model's performance within solid-liquid equilibria (SLE) in binary mixtures (methane + ethane, methane + heptane, methane + benzene, methane + CO2, ethane + heptane, ethane + CO2, 1-propanol + 1,4-dioxane, ethanol + water, 2-propanol + water) is presented. Th....... The results from the binary mixtures are used to predict SLE behaviour in ternary mixtures (methane + ethane + heptane, methane + ethane + CO2). Our results are compared with experimental data found in the literature....

  9. Modelling phase equilibria for acid gas mixtures using the CPA equation of state. Part V: Multicomponent mixtures containing CO2 and alcohols

    DEFF Research Database (Denmark)

    Tsivintzelis, Ioannis; Kontogeorgis, Georgios M.

    2015-01-01

    of CPA for ternary and multicomponent CO2 mixtures containing alcohols (methanol, ethanol or propanol) water and hydrocarbons. This work belongs to a series of studies aiming to arrive in a single "engineering approach" for applying CPA to acid gas mixtures, without introducing significant changes...... to the model. In this direction, CPA results were obtained using various approaches, i.e. different association schemes for pure CO2 (assuming that it is a non-associating compound, or that it is a self-associating fluid with two, three or four association sites) and different possibilities for modelling...... mixtures of CO2 with water and alcohols (only use of one interaction parameter kij or assuming cross-association interactions and obtaining the relevant parameters either via a combining rule or using an experimental value for the cross-association energy). It is concluded that CPA is a powerful model...

  10. Blood clotting and platelets: a delicate balance

    International Nuclear Information System (INIS)

    Heyns, A. du P.; Loetter, M.G.; Badenhorst, P.N.

    1988-01-01

    The Medical Research Council Blood Platelet Research Unit has studied many of the facets of platelets. The research highlights of the Unit include the following: the identification of ADPase, an enzyme found in the blood vessel wall, which breaks down adenosine diphospate (ADP) to adenosine, and which inhibits platelet aggregation; the determination of the relationship between the biochemical activity of the vessel wall with the development of atherosclerosis; the development of a method to label platelets with the compound In-111-oxine; the use of labelled platelets to study platelets in the spleen: an investigation of the life-span of platelets, which revealed how aged platelets are removed from circulation, and recently a study of methods to demonstrate in vivo activation of platelets. 1 fig

  11. Application of artificial neural networks for the determination of proteins with CPA-pI by rayleigh light scattering technique

    Energy Technology Data Exchange (ETDEWEB)

    Dong Lijun [Department of Chemistry, Lanzhou University, Lanzhou 730000 (China); Chen Xingguo [Department of Chemistry, Lanzhou University, Lanzhou 730000 (China)]. E-mail: chenxg@lzu.edu.cn; Hu Zhide [Department of Chemistry, Lanzhou University, Lanzhou 730000 (China)

    2007-05-15

    The determination of proteins with 2-(4-chloro-2-phosphonophenylazo)-7-(4-iodophenylazo) -1,8-dihydroxynaphthalene-3,6-disulfonic acid (CPA-pI) by Rayleigh light scattering (RLS) was studied in this paper. The weak RLS of CPA-pI and BSA can be enhanced greatly by the addition of Al{sup 3+} at the pH 5.6 and an enhanced RLS signal was produced at 365-385 nm. Based on the reaction of CPA-pI, Al{sup 3+} and proteins, a new quantitative determination method for proteins has been developed. The effect of three variables for the determination of proteins was optimized by means of artificial neural networks (ANNs) using extended delta-bar-delta (EDBD) algorithms with the optimal network structure of 3-5-1. This method is very sensitive (2.5-35.4 {mu}g/ml for bovine serum albumin (BSA)), rapid (<2 min), simple (one step) and tolerance of most interfering substances. Six samples of protein in human serum were determined and the maximum relative error is no more than 2% and the recovery is between 95% and 105%.

  12. Extended Storage of Pathogen-Reduced Platelet Concentrates (PRECON)

    Science.gov (United States)

    2017-12-01

    transfusion. Our project proposes to determine the efficacy of using a pathogen inactivation technique (Mirasol) coupled with a platelet additive solution (PAS...technology, platelet additive solution, platelet recovery and survival, platelet storage, platelet storage solution, platelets, thrombocytopenia, transfusion...Platelets Report to 2017 Military Health System Research Symposium ……………………………………………………………….. 29 Extended Storage of Pathogen-Reduced Platelet Concentrates

  13. Effect of losartan on human platelet activation.

    Science.gov (United States)

    Guerra-Cuesta, J I; Montón, M; Rodríguez-Feo, J A; Jiménez, A M; González-Fernández, F; Rico, L A; García, R; Gómez, J; Farré, J; Casado, S; López-Farré, A

    1999-03-01

    Previous studies have demonstrated that losartan can block the thromboxane A2 receptor on the vascular wall. The aim of the present study was to assess the effect of losartan on human platelet activation. Platelets were obtained from 15 healthy men, aged 26-40 years. Platelet activation was measured by changes in the light transmission of platelet-rich plasma stimulated by the thromboxane A2 analog U46619 (5 x 10(-6) mol/l) or ADP (10(-5) mol/l). U46619-stimulated platelet aggregation was significantly inhibited by losartan in a dose-dependent manner. Only a high dose of EXP 3174 (5 x 10(-5) mol/l), the in vivo active metabolite of losartan, was able to attenuate U46619-induced platelet activation. Captopril, an angiotensin I converting inhibitor, failed to modify U46619-induced platelet aggregation. Furthermore, the binding of [3H]-U46619 to platelets was competitively inhibited by losartan, whereas only a high dose of EXP 3174 reduced the binding of [3H]-U46619. Captopril failed to modify the binding of [3H]-U46619 to platelets. Losartan also reduced the platelet activation induced by ADP (10(-5) mol/l), a platelet agonist partially dependent on thromboxane A2. In addition, when thromboxane A2 generation was blocked by aspirin, ADP-induced platelet aggregation was inhibited to a similar degree to the inhibition induced by losartan. Exogenous angiotensin II did not elicit any modification of either U46619- or ADP-stimulated platelet aggregation. Losartan decreased platelet aggregation by a thromboxane A2-dependent mechanism. EXP 3174 was less potent than losartan in reducing thromboxane A2-dependent platelet activation. Captopril and exogenous angiotensin II had no effect on human platelet activation. These results suggest that losartan reduced thromboxane A2-dependent platelet activation independently of its effect on angiotensin II.

  14. Peroxiredoxin II is an antioxidant enzyme that negatively regulates collagen-stimulated platelet function.

    Science.gov (United States)

    Jang, Ji Yong; Wang, Su Bin; Min, Ji Hyun; Chae, Yun Hee; Baek, Jin Young; Yu, Dae-Yeul; Chang, Tong-Shin

    2015-05-01

    Collagen-induced platelet signaling is mediated by binding to the primary receptor glycoprotein VI (GPVI). Reactive oxygen species produced in response to collagen have been found to be responsible for the propagation of GPVI signaling pathways in platelets. Therefore, it has been suggested that antioxidant enzymes could down-regulate GPVI-stimulated platelet activation. Although the antioxidant enzyme peroxiredoxin II (PrxII) has emerged as having a role in negatively regulating signaling through various receptors by eliminating H2O2 generated upon receptor stimulation, the function of PrxII in collagen-stimulated platelets is not known. We tested the hypothesis that PrxII negatively regulates collagen-stimulated platelet activation. We analyzed PrxII-deficient murine platelets. PrxII deficiency enhanced GPVI-mediated platelet activation through the defective elimination of H2O2 and the impaired protection of SH2 domain-containing tyrosine phosphatase 2 (SHP-2) against oxidative inactivation, which resulted in increased tyrosine phosphorylation of key components for the GPVI signaling cascade, including Syk, Btk, and phospholipase Cγ2. Interestingly, PrxII-mediated antioxidative protection of SHP-2 appeared to occur in the lipid rafts. PrxII-deficient platelets exhibited increased adhesion and aggregation upon collagen stimulation. Furthermore, in vivo experiments demonstrated that PrxII deficiency facilitated platelet-dependent thrombus formation in injured carotid arteries. This study reveals that PrxII functions as a protective antioxidant enzyme against collagen-stimulated platelet activation and platelet-dependent thrombosis. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  15. Independent control of arbitrary orders of dispersion at the high power end of CPA lasers

    International Nuclear Information System (INIS)

    Goerbe, M.; Jojart, P.; Szeged University, Szeged; Kovacs, M.; Osvay, K.

    2010-01-01

    Complete text of publication follows. One of the most crucial issues in chirped pulse amplification (CPA) systems is the precise temporal recompression of the pulses hitting the target. In case of few cycle high intensity lasers, the stabilization of the carrier-envelope phase (CEP) of the pulses is also required. An acousto-optical programmable dispersion filter can satisfy both aims, providing dispersion (pre)compensation up to the fourth order of dispersion and make the CEP shift stable. Its use is, however, limited to a pulse intensity of 100 MW/cm 2 , hence its application is restricted to the front end of the (OP)CPA laser systems. A simple optical arrangement consisting of wedges with different materials and different apex angles was proposed recently for isochronic control of CEP of a pulse train. In this paper we show that assembly of wedges can be specifically designed to tune only one of the dispersion coefficients, while all the others, including CEP, remain practically unchanged. Wedge pairs changing solely the zeroth (CEP) and second order (group delay) dispersion (GDD) are experimentally presented along with a triplet of wedges tuning the third order dispersion (TOD) only. The experiment was carried out with the use of spectrally resolved interferometry (SRI). A Michelson-interferometer was illuminated by 100 nm bandwidth laser pulses of a Ti:Sapphire oscillator. The sample arm of the interferometer contained the wedge assembly, set to near Brewster-angle incidence at each surfaces, designed for tuning the required order of dispersion. At the output of the interferometer the spectral interference between the pulses from the sample and reference arms was resolved with a spectrograph. The dispersion was tuned by perpendicular shift of the entire wedge assembly to the laser beam. In the measurements spectral interferograms were recorded and evaluated at each spatial position of the assembly. Three different wedge combinations, two doublets and a triplet

  16. Platelet-rich plasma and chronic wounds: remaining fibronectin may influence matrix remodeling and regeneration success.

    Science.gov (United States)

    Moroz, Andrei; Deffune, Elenice

    2013-11-01

    Platelet-rich plasma has been largely used as a therapeutic option for the treatment of chronic wounds of different etiologies. The enhanced regeneration observed after the use of platelet-rich plasma has been systematically attributed to the growth factors that are present inside platelets' granules. We hypothesize that the remaining plasma and platelet-bound fibronectin may act as a further bioactive protein in platelet-rich plasma preparations. Recent reports were analyzed and presented as direct evidences of this hypotheses. Fibronectin may directly influence the extracellular matrix remodeling during wound repair. This effect is probably through matrix metalloproteinase expression, thus exerting an extra effect on chronic wound regeneration. Physicians should be well aware of the possible fibronectin-induced effects in their future endeavors with PRP in chronic wound treatment. Copyright © 2013 International Society for Cellular Therapy. Published by Elsevier Inc. All rights reserved.

  17. Evaluation of platelet aggregation in platelet concentrates: storage implications

    Directory of Open Access Journals (Sweden)

    Neiva Teresinha J.C.

    2003-01-01

    Full Text Available The use of hemo-derivatives is nowadays a fundamentally important therapeutic modality in the exercise of medicine. Among the various hemo-components employed, we have the platelet concentrate (PC, indicated in cases of hemorrhagic disturbances. We previously showed that platelet function in blood donors is reduced in their screening phase and after the separation process of PCs. Currently, we are providing evidence for the existence of biochemical and functional changes in PC preparations stored for three days at temperatures of 20 ± 2 ºC. Platelet concentrates from 40 healthy donors, collected in CPD anticoagulant and PL-146 polyvinylchloride containers, were examined in order to determine the pH value, pCO2 ,pO2 and lactate concentrations. In addition, the aggregation of platelets with thrombin and collagen were examined to evaluate platelet function. A pH increase from 7.07 ± 0.04 to 7.36 ± 0.07 (p < 0.01 was observed. The pCO2 concentration decreased progressively from 69.2 ± 7.7 mmHg to 28.8 ± 6.2 mmHg (p < 0.001 during the storage period. In contrast, pO2 value increase from 103.4 ± 30.6 to 152.3 ± 24.6 mmHg (p < 0.001 was evidenced during the 48 hours of storage. The lactate concentration increased from 17.97 ± 5.2 to 57.21 ± 5.7 mg/dl (p < 0.001. Platelet aggregation using 0.25 U/ml-thrombin and 2.0 µg/ml-collagen showed significant hypofunction from 61.8 ± 2.7% to 24.8 ± 9.8% and 62.7±5.0 to 33.4± 6.2 (p < 0.001, respectively. We concluded that the evaluated biochemical parameters and the platelet function changed significantly when the platelets were kept under routine storage conditions.

  18. Multiple alterations of platelet functions dominated by increased secretion in mice lacking Cdc42 in platelets

    DEFF Research Database (Denmark)

    Pleines, Irina; Eckly, Anita; Elvers, Margitta

    2010-01-01

    formation and exocytosis in various cell types, but its exact function in platelets is not established. Here, we show that the megakaryocyte/platelet-specific loss of Cdc42 leads to mild thrombocytopenia and a small increase in platelet size in mice. Unexpectedly, Cdc42-deficient platelets were able to form...

  19. Encapsulation of Clay Platelets inside Latex Particles

    NARCIS (Netherlands)

    Voorn, D.J.; Ming, W.; Herk, van A.M.; Fernando, R.H.; Sung, Li-Piin

    2009-01-01

    We present our recent attempts in encapsulating clay platelets inside latex particles by emulsion polymerization. Face modification of clay platelets by cationic exchange has been shown to be insufficient for clay encapsulation, leading to armored latex particles. Successful encapsulation of

  20. Prolonged platelet preservation by transient metabolic suppression

    NARCIS (Netherlands)

    Badlou, Bahram Alamdary

    2006-01-01

    Introduction: Different clinical studies have shown that transfusion of stored platelets results in better haemostasis in patients with thrombocytopenia with and without a platelet function defect. Objectives: Current preservation procedures aim to optimally preserve the metabolic status of

  1. Aspirin Inhibits Platelet-Derived Sphingosine-1-Phosphate Induced Endothelial Cell Migration.

    Science.gov (United States)

    Polzin, Amin; Knoop, Betül; Böhm, Andreas; Dannenberg, Lisa; Zurek, Mark; Zeus, Tobias; Kelm, Malte; Levkau, Bodo; Rauch, Bernhard H

    2018-01-01

    Aspirin plays a crucial role in the prevention of cardiovascular diseases. We previously described that aspirin has effects beyond inhibition of platelet aggregation, as it inhibited thrombin-mediated release of sphingosine-1-phosphate (S1P) from human platelets. S1P is a bioactive lipid with important functions on inflammation and apoptosis. In endothelial cells (EC), S1P is a key regulator of cell migration. In this study, we aimed to analyze the effects of aspirin on platelet-induced EC migration. Human umbilical EC migration was measured by Boyden chamber assay. EC migration was induced by platelet supernatants of thrombin receptor-activating peptide-1 (AP1) stimulated platelets. To investigate the S1P receptor subtype that promotes EC migration, specific inhibitors of S1P receptor subtypes were applied. S1P induced EC migration in a concentration-dependent manner. EC migration induced by AP1-stimulated platelet supernatants was reduced by aspirin. S1P1 receptor inhibition almost completely abolished EC migration induced by activated platelets. The inhibition of S1P2 or S1P3 receptor had no effect. Aspirin inhibits EC migration induced by activated platelets that is in part due to S1P and mediated by the endothelial S1P1 receptor. The clinical significance of this novel mechanism of aspirin action has to be investigated in future studies. © 2017 S. Karger AG, Basel.

  2. Toward the Relevance of Platelet Subpopulations for Transfusion Medicine

    Directory of Open Access Journals (Sweden)

    Stefan Handtke

    2018-02-01

    Full Text Available Circulating platelets consist of subpopulations with different age, maturation state and size. In this review, we address the association between platelet size and platelet function and summarize the current knowledge on platelet subpopulations including reticulated platelets, procoagulant platelets and platelets exposing signals to mediate their clearance. Thereby, we emphasize the impact of platelet turnover as an important condition for platelet production in vivo. Understanding of the features that characterize platelet subpopulations is very relevant for the methods of platelet concentrate production, which may enrich or deplete particular platelet subpopulations. Moreover, the concept of platelet size being associated with platelet function may be attractive for transfusion medicine as it holds the perspective to separate platelet subpopulations with specific functional capabilities.

  3. Potential fluid mechanic pathways of platelet activation

    OpenAIRE

    Shadden, Shawn C.; Hendabadi, Sahar

    2012-01-01

    Platelet activation is a precursor for blood clotting, which plays leading roles in many vascular complications and causes of death. Platelets can be activated by chemical or mechanical stimuli. Mechanically, platelet activation has been shown to be a function of elevated shear stress and exposure time. These contributions can be combined by considering the cumulative stress or strain on a platelet as it is transported. Here we develop a framework for computing a hemodynamic-based activation ...

  4. Platelet activation in outpatients undergoing esophagogastroduodenoscopy

    International Nuclear Information System (INIS)

    Sagripanti, A.; Polloni, A.; Materazzi, F.; Ferdeghini, M.; Pinori, E.; Bianchi, R.

    1989-01-01

    To evaluate the influence of emotional stress on platelet function mesured by radioimmunoassay in plasma two platelet factor 4, in a series of outpatients undergoing esophagogastroduodenoscopy for upper digestive complaints has been measured. The plasma levels of β-thromboglobulin and platelet factor 4, determined just before the instrumental examination, were significantly more elevated as compared to basal values, checked a week later. These results provide evidence of enhanced in vivo platelet release reaction during emotional stress

  5. Further studies on the relationship between platelet buoyant density and platelet age

    International Nuclear Information System (INIS)

    Boneu, B.; Vigoni, F.; Boneu, A.; Caranobe, C.; Sie, P.

    1982-01-01

    The relationship between platelet buoyant density and platelet age was investigated in eight human subjects submitted to an autologous chromium labeled platelet survival study. Platelets were isolated after isopycnic centrifugation using eight discontinuous isoosmotic stractan gradients (five subjects), or various continuous and linear isoosmolar gradients (three subjects). A paradoxical radioactivity enrichment of the dense platelets and a premature loss of radioactivity in the light platelets were observed. These results are explained by a shift of the radioactivity distribution curve toward higher densities during the 3-4 days after platelet injection, while the standard deviation of the distribution was conserved throughout the platelet life span. These results suggest that young platelets are heterogeneous and slightly less dense than the total platelet population

  6. Selection of donor platelets for alloimmunized patients using a platelet-associated IgG assay

    International Nuclear Information System (INIS)

    Myers, T.J.; Kim, B.K.; Steiner, M.; Baldini, M.G.

    1981-01-01

    A quantitative immunofluorescence platelet-associated immunoglobulin-G (PA-IgG) assay was used to detect alloimmunity to platelets in 8/12 multitransfused patients and to perform platelet crossmatching in the 8 alloimmunized patients. The correct separation of multitransfused patients into alloimmune and nonalloimmune groups was substantiated with chromium-51-labeled platelet survival studies. For 5 alloimmunized patients, compatible and incompatible donor platelets were demonstrated by PA-IgG crossmatching and were confirmed by platelet survival studies. With the other 3 alloimmunized patients, only Pa-IgG incompatible donor platelets were found. Survival studies with 5 of these incompatible donor platelets showed markedly reduced survival times on 4 occasions. Pa-IgG compatible donor platelets survived 3.5 to 8.7 days, while Pa-IgG incompatible platelets showed survival times of 0.1 to 2.4 days

  7. Platelet function testing in pediatric patients

    DEFF Research Database (Denmark)

    Hvas, Anne-Mette; Favaloro, Emmanuel J

    2017-01-01

    Introduction: Platelets play a key role in primary hemostasis and are also intricately linked to secondary hemostasis. Investigation of platelet function in children, especially in neonates, is seriously challenged by the volumes required to perform the majority of platelet function tests and due...

  8. Platelet counting using the Coulter electronic counter.

    Science.gov (United States)

    Eggleton, M J; Sharp, A A

    1963-03-01

    A method for counting platelets in dilutions of platelet-rich plasm using the Coulter electronic counter is described.(1) The results obtained show that such platelet counts are at least as accurate as the best methods of visual counting. The various technical difficulties encountered are discussed.

  9. Platelets Inhibit Migration of Canine Osteosarcoma Cells.

    Science.gov (United States)

    Bulla, S C; Badial, P R; Silva, R C; Lunsford, K; Bulla, C

    2017-01-01

    The interaction between platelets and tumour cells is important for tumour growth and metastasis. Thrombocytopenia or antiplatelet treatment negatively impact on cancer metastasis, demonstrating potentially important roles for platelets in tumour progression. To our knowledge, there is no information regarding the role of platelets in cancer progression in dogs. This study was designed to test whether canine platelets affected the migratory behaviour of three canine osteosarcoma cell lines and to give insights of molecular mechanisms. Intact platelets, platelet lysate and platelet releasate inhibited the migration of canine osteosarcoma cell lines. Addition of blood leucocytes to the platelet samples did not alter the inhibitory effect on migration. Platelet treatment also significantly downregulated the transcriptional levels of SNAI2 and TWIST1 genes. The interaction between canine platelets or molecules released during platelet activation and these tumour cell lines inhibits their migration, which suggests that canine platelets might antagonize metastasis of canine osteosarcoma. This effect is probably due to, at least in part, downregulation of genes related to epithelial-mesenchymal transition. Copyright © 2016. Published by Elsevier Ltd.

  10. Platelet kinetics: the state of the art

    International Nuclear Information System (INIS)

    Heyns, A. duP

    1984-01-01

    In this paper an overview of the state of the art of platelet kinetics 1982 is presented. The subjects considered include a discussion of the advantages and disadvantages of some of the many radionuclide platelet labels, viz 51 Cr, 111 In, focussing briefly on models for analysis of platelets survival. (Auth.)

  11. Determination of enterotoxigenic Clostridium perfringens by detecting of the cpa and cpe genes in stool samples of human origin, associated to gastrointestinal disease

    International Nuclear Information System (INIS)

    Oropeza Barrios, Gletty

    2014-01-01

    A molecular methodology is provided to the Centro Nacional de Referencia de Bacteriologia (CNRB) of the Instituto Costarricense de Investigacion y Ensenanza en Nutricion y Salud. An opportune diagnosis is realized of enterotoxigenic Clostridium perfringens in stool samples of sporadic cases and cases associated to foodborne disease outbreaks. DNA extraction of the white microorganism was performed through the methodology implemented in the CNRB. The technique of polymerase chain reaction (PCR) were adapted and standardized to establish the identification of C. perfringens to species level and detection of cpe gene coding for enterotoxin. The sensitivity of the method was determined in a selective culture medium for C. perfringens (Tryptose sulfite cycloserine Agar). A detection limit of about 2,3 x 10 4 CFU/ml was reached for the cpe gene and at least 2,8 x 10 2 CFU/ml for the cpa gene. Retrospective analysis of 61 samples of diarrheal stool suspicious by C. perfringens is performed to evaluate the efficacy of the technique. Three outbreaks caused by C. perfringens were identified and a 10% of positivity in the samples were obtained analyzed during the period between July 2012-March 2014 [es

  12. Critical off-target effects of the widely used Rac1 inhibitors NSC23766 and EHT1864 in mouse platelets

    DEFF Research Database (Denmark)

    Dütting, Sebastian; Heidenreich, Julius; Cherpokova, Deya

    2015-01-01

    BACKGROUND: Platelet aggregation at sites of vascular injury is essential for normal hemostasis, but may also cause pathological vessel occlusion. Rho GTPases are molecular switches that regulate essential cellular processes and they have pivotal functions in the cardiovascular system. Rac1......, have been characterized in different cell types, demonstrating high specificity for Rac1 or Rac, respectively. OBJECTIVES: We sought to analyze the specificity of NSC23766 and EHT1864. METHODS: Platelet function was assessed in mouse wild-type and Rac1-deficient platelets by using flow cytometric...... function tests. Both inhibitors induced a Rac1-specific inhibition of platelet spreading, but also markedly impaired agonist-induced activation of Rac1(-/-) platelets. Furthermore, GPIb-mediated signaling was dramatically inhibited by NSC23766 in both wild-type and Rac1-deficient platelets. Importantly...

  13. Platelets retain high levels of active plasminogen activator inhibitor 1.

    Directory of Open Access Journals (Sweden)

    Helén Brogren

    Full Text Available The vascular fibrinolytic system is crucial for spontaneous lysis of blood clots. Plasminogen activator inhibitor 1 (PAI-1, the principal inhibitor of the key fibrinolytic enzyme tissue-type plasminogen activator (tPA, is present in platelets at high concentrations. However, the majority of PAI-1 stored in platelets has been considered to be inactive. Our recent finding (Brogren H, et al. Blood 2004 that PAI-1 de novo synthesized in platelets remained active for over 24 h, suggested that PAI-1 stored in the α-granules might be active to a larger extent than previously reported. To re-evaluate this issue, we performed experiments where the fraction of active PAI-1 was estimated by analyzing the tPA-PAI-1 complex formation. In these experiments platelets were lysed with Triton X-100 in the presence of serial dilutions of tPA and subsequently the tPA-PAI-1 complex was evaluated by Western blot. Also, using a non-immunologic assay, tPA was labeled with (125I, and (125I-tPA and (125I-tPA-PAI-1 was quantified by scintigraphy. Interestingly, both methods demonstrated that the majority (>50% of platelet PAI-1 is active. Further analyses suggested that pre-analytical procedures used in previous studies (sonication or freezing/thawing may have substantially reduced the activity of platelet PAI-1, which has lead to an underestimation of the proportion of active PAI-1. Our in vitro results are more compatible with the role of PAI-1 in clot stabilization as demonstrated in physiological and pathophysiological studies.

  14. Effect of ionizing radiation on platelet function in vitro

    International Nuclear Information System (INIS)

    Kalovidouris, A.E.; Papayannis, A.G.

    1981-01-01

    The effect of ionizing radiation on platelet function was investigated in vitro. Platelet-rich plasma (300x10 9 /l) was irradiated with doses of 1, 4, 10, 20 and 50 Gy. Platelet function tests were performed on both irradiated and control (non-irradiated) platelet samples. The platelet function tests were (1) platelet aggregation by ADP (1, 2, 4 μmol final concentration), adrenaline and collagen, (2) ADP-release from platelets, (3) clot retraction and (4) platelet factor-3 availability. It was found that roentgen irradiation of platelets in vitro did not affect these platelet function tests. (Auth.)

  15. Platelet count and platelet indices in women with preeclampsia.

    Science.gov (United States)

    AlSheeha, Muneera A; Alaboudi, Rafi S; Alghasham, Mohammad A; Iqbal, Javed; Adam, Ishag

    2016-01-01

    Although the exact pathophysiology of preeclampsia is not completely understood, the utility of different platelets indices can be utilized to predict preeclampsia. To compare platelet indices, namely platelet count (PC), mean platelet volume (MPV), platelet distribution width (PDW), and PC to MPV ratio in women with preeclampsia compared with healthy controls. Qassim Hospital, Kingdom of Saudi Arabia. A case-control study. Sixty preeclamptic women were the cases and an equal number of healthy pregnant women were the controls. There was no significant difference in age, parity, and body mass index between the study groups. Sixteen and 44 of the cases were severe and mild preeclampsia, respectively. There was no significant difference in PDW and MPV between the preeclamptic and control women. Both PC and PC to MPV ratios were significantly lower in the women with preeclampsia compared with the controls. There was no significant difference in the PC, PDW, MPV, and PC to MPV ratio when women with mild and severe preeclampsia were compared. Using receiver operating characteristic (ROC) curves, the PC cutoff was 248.0×10 3 /µL for diagnosis of pre-eclampsia ( P =0.019; the area under the ROC curve was 62.4%). Binary regression suggests that women with PC preeclampsia (odds ratio =2.2, 95% confidence interval =1.08-4.6, P =0.03). The PC/MPV cutoff was 31.2 for diagnosis of preeclampsia ( P =0.035, the area under the ROC curve was 62.2%). PC preeclampsia.

  16. A Community-Engaged Approach to Developing a Mobile Cancer Prevention App: The mCPA Study Protocol

    Science.gov (United States)

    2016-01-01

    Background Rapid growth of mobile technologies has resulted in a proliferation of lifestyle-oriented mobile phone apps. However, most do not have a theoretical framework and few have been developed using a community-based participatory research approach. A community academic team will develop a theory-based, culturally tailored, mobile-enabled, Web-based app—the Mobile Cancer Prevention App (mCPA)—to promote adherence to dietary and physical activity guidelines. Objective The aim of this study is to develop mCPA content with input from breast cancer survivors. Methods Members of SISTAAH (Survivors Involving Supporters to Take Action in Advancing Health) Talk (N=12), treated for Stages I-IIIc breast cancer for less than 1 year, 75 years of age or younger, and English-speaking and writing, will be recruited to participate in the study. To develop the app content, breast cancer survivors will engage with researchers in videotaped and audiotaped sessions, including (1) didactic instructions with goals for, benefits of, and strategies to enhance dietary intake and physical activity, (2) guided discussions for setting individualized goals, monitoring progress, and providing or receiving feedback, (3) experiential nutrition education through cooking demonstrations, and (4) interactive physical activity focused on walking, yoga, and strength training. Qualitative (focus group discussions and key informant interviews) and quantitative (sensory evaluation) methods will be used to evaluate the participatory process and outcomes. Results Investigators and participants anticipate development of an acceptable (frequency and duration of usage) feasible (structure, ease of use, features), and accessible mobile app available for intervention testing in early 2017. Conclusions Depending on the availability of research funding, mCPA testing, which will be initiated in Miami, will be extended to Chicago, Houston, Philadelphia, and Los Angeles. PMID:26935995

  17. A Community-Engaged Approach to Developing a Mobile Cancer Prevention App: The mCPA Study Protocol.

    Science.gov (United States)

    Smith, Selina Ann; Whitehead, Mary Smith; Sheats, Joyce; Mastromonico, Jeff; Yoo, Wonsuk; Coughlin, Steven Scott

    2016-03-02

    Rapid growth of mobile technologies has resulted in a proliferation of lifestyle-oriented mobile phone apps. However, most do not have a theoretical framework and few have been developed using a community-based participatory research approach. A community academic team will develop a theory-based, culturally tailored, mobile-enabled, Web-based app-the Mobile Cancer Prevention App (mCPA)-to promote adherence to dietary and physical activity guidelines. The aim of this study is to develop mCPA content with input from breast cancer survivors. Members of SISTAAH (Survivors Involving Supporters to Take Action in Advancing Health) Talk (N=12), treated for Stages I-IIIc breast cancer for less than 1 year, 75 years of age or younger, and English-speaking and writing, will be recruited to participate in the study. To develop the app content, breast cancer survivors will engage with researchers in videotaped and audiotaped sessions, including (1) didactic instructions with goals for, benefits of, and strategies to enhance dietary intake and physical activity, (2) guided discussions for setting individualized goals, monitoring progress, and providing or receiving feedback, (3) experiential nutrition education through cooking demonstrations, and (4) interactive physical activity focused on walking, yoga, and strength training. Qualitative (focus group discussions and key informant interviews) and quantitative (sensory evaluation) methods will be used to evaluate the participatory process and outcomes. Investigators and participants anticipate development of an acceptable (frequency and duration of usage) feasible (structure, ease of use, features), and accessible mobile app available for intervention testing in early 2017. Depending on the availability of research funding, mCPA testing, which will be initiated in Miami, will be extended to Chicago, Houston, Philadelphia, and Los Angeles.

  18. Solid-Liquid Equilibria for Many-component Mixtures Using Cubic-Plus-Association (CPA) equation of state

    DEFF Research Database (Denmark)

    Fettouhi, André; Thomsen, Kaj

    2010-01-01

    In the creation of liquefied natural gas the formation of solids play a substantial role, hence detailed knowledge is needed about solid-liquid equilibria (SLE). In this abstract we shortly summarize the work we have carried out at CERE over the past year with SLE for many-component mixtures usin...... the Cubic-Plus-Association (CPA) equation of state. Components used in this work are highly relevant to the oil and gas industry and include light and heavy hydrocarbons, alcohols, water and carbon dioxide....

  19. Mutual Solubility of MEG, Water and Reservoir Fluid: Experimental Measurements and Modeling using the CPA Equation of State

    DEFF Research Database (Denmark)

    Riaz, Muhammad; Kontogeorgis, Georgios; Stenby, Erling Halfdan

    2011-01-01

    This work presents new experimental phase equilibrium data of binary MEG-reservoir fluid and ternary MEG-water-reservoir fluid systems at temperatures 275-326 K and at atmospheric pressure. The reservoir fluid consists of a natural gas condensate from a Statoil operated gas field in the North Sea...... compounds. It has also been extended to reservoir fluids in presence of water and polar chemicals using a Pedersen like characterization method with modified correlations for critical temperature, pressure and acentric factor. In this work CPA is applied to the prediction of mutual solubility of reservoir...

  20. Modeling MEA with the CPA equation of state: A parameter estimation study adding local search to PSO algorithm

    DEFF Research Database (Denmark)

    Santos, Letícia Cotia dos; Tavares, Frederico Wanderley; Ahón, Victor Rolando Ruiz

    2015-01-01

    parameters for MEA. This work proposes adding LLE information systematically in the CPA parameter estimation procedure. At first, the parameter search space is defined by the results from the PSO sensitivity analysis for VLE considering the experimental error for vapor pressures and liquid densities...... (objective function cut off). Then, two possible methodologies are discussed: the first one uses all the possible parameter sets and check them against the LLE and VLE experimental data. The second method explicitly incorporates LLE information into the objective function and uses both PSO and PSO...

  1. Evidence that platelet buoyant density, but not size, correlates with platelet age in man

    International Nuclear Information System (INIS)

    Mezzano, D.; Hwang, K.; Catalano, P.; Aster, R.H.

    1981-01-01

    Following infusion of 51Cr-labeled autologous platelets into normal subjects, high-density (HD) and low-density (LD) platelet cohorts were isolated by prolonged centrifugation in isosmotic arabino-galactan (Stractan). Specific radio-activity of LD platelets declined rapidly post-infusion (T1/2 . 1.5 days), but specific radioactivity of HD platelets remained constant or increased over a 3--4-day period and gradually declined for 6--7 days thereafter. These differences were exaggerated when platelet cohorts enriched in LD or HD cells by slow centrifugation in high-density albumin were labeled and transfused. Mean survival of a platelet cohort enriched with HD cells was significantly (P less than 0.02) shorter (7.73 days) than that of a cohort enriched with LD cells (9.33) days). In normal subjects treated with aspirin, capacity for thromboxane synthesis was regained more rapidly (P less than 0.05) in LD than in HD platelets. HD and LD platelets differed only slightly in mean volume (HD platelets . 7.57 mu3, LD platelets . 6.87 mu3, 0.05 less than P less than 0.01). We believe the most logical interpretation of these findings is that under normal conditions in man, newly formed platelets are less dense on the average than total platelets and become more dense as they age in the circulation. Thus, specific radioactivity of LD platelets declines rapidly as these platelets move into a more dense compartment and are replaced by newly formed, unlabelled cells; specific radioactivity of HD platelets remains constant or increases as labelled platelets enter this compartment in numbers equal to or greater than the number leaving it at the end of their life span. The similarity in mean volumes of LD and HD platelets suggests that platelet size is unrelated to platelet age under normal conditions

  2. Methods for evaluation of platelet function.

    Science.gov (United States)

    Lindahl, Tomas L; Ramström, Sofia

    2009-10-01

    There are a multitude of platelet function tests available, reflecting the complex nature of the platelet in haemostasis. No simple single test will ever cover all aspects of platelet function. Some tests focus on the aggregation of platelets, for example aggregometry, other on the swelling in response to hypotonic solutions, i.e. the well-known hypotonic shock response, or adhesion or coagulation and clot retraction, for example thromboelastography. In general there is a lack of clinical studies showing a predictive value of analysis of platelet concentrates.

  3. Design and performance of a fast thermal response miniature Chromium Potassium Alum (CPA) salt pill for use in a millikelvin cryocooler

    Science.gov (United States)

    Bartlett, J.; Hardy, G.; Hepburn, I. D.

    2015-01-01

    The design and performance of a fast thermal response miniature (24 mm outer diameter by 30 mm long) Chromium Potassium Alum (CPA) salt pill is described. The need for a fast thermal response has been driven by the development of a continuously operating millikelvin cryocooler (mKCC) which uses 2 T superconducting magnets that can be ramped to full field in 30 s. The consequence of magnetising and demagnetising the CPA pill in such a short time is that thermal boundary resistance and eddy current heating have a significant impact on the performance of the pill, which was investigated in detail using modelling. The complete design of a prototype CPA pill is described in this paper, including the methods used to minimise thermal boundary resistance and eddy current heating as well as the manufacturing and assembly processes. The performance of the prototype CPA pill operated from a 3.6 K bath is presented, demonstrating that a complete CPA cycle (magnetising, cooling to bath and demagnetising) can be accomplished in under 2.5 min, with magnetisation and demagnetisation taking just 30 s each. The cold finger base temperature of the prototype varies with demagnetisation speed as a consequence of eddy current heating; for a 30 s demagnetisation, a base temperature of 161 mK is obtained, whilst for a 5 min demagnetisation, a base temperature of 149 mK was measured (both from a 3.6 K and 2 T starting position). The measured hold times of the CPA pill at 200 mK, 300 mK, and 1 K are given, proving that the hold time far exceeds the recycle time and demonstrating the potential for continuous operation when two ADRs are used in a tandem configuration. The ease and speed at which the CPA pill temperature can be changed and controlled when stepping between operating temperatures in the range of 200 mK to 4 K using a servo control program is also shown, once again highlighting the excellent thermal response of the pill. All of the test results are in good agreement with the

  4. Defining Platelet Function During Polytrauma

    Science.gov (United States)

    2014-04-01

    scaffold of the clot after its thrombin-induced polymerization to fibrin fibers. Formation of a stiff fibrin fiber network and its contraction by platelet...In another study (PROTEC T) Refused Participat ion (Yes=Y, No=N, W=Unqua lified , Refused further draws (agreed to keep previous data

  5. Structure Features and Anti-Gastric Ulcer Effects of Inulin-Type Fructan CP-A from the Roots of Codonopsis pilosula (Franch.) Nannf.

    Science.gov (United States)

    Li, Jiankuan; Wang, Tao; Zhu, Zhichuan; Yang, Fengrong; Cao, Lingya; Gao, Jianping

    2017-12-18

    Radix Codonopsis has been used in traditional Chinese medicine for strengthening the immune system, improving poor gastrointestinal function, treating gastric ulcers and chronic gastritis and so on. In the present study, an inulin-type fructan CP-A was obtained from the roots of Codonopsis pilosula (Franch.) Nannf. and its structure was confirmed by MS and NMR as (2 → 1) linked-β-d-fructofuranose. The protective effects of CP-A against ethanol-induced acute gastric ulcer in rats were intensively investigated. A Lacy assay demonstrated that CP-A-treated group (50 mg/kg) showed the gastric damage level 1, which was similar to the positive control group, while the model group exhibited the gastric damage level 3. The Guth assay demonstrated that the mucosa ulcer index for CP-A groups at the doses of 50 mg/kg and 25 mg/kg significantly decreased compared with that in the model group ( p CP-A significantly increased the activities of SOD and GSH-Px, and decreased the contents of MDA and NO, and the activity of MPO in gastric tissue in a dose-dependent manner ( p CP-A were likely the potential component in Radix Codonopsis for treatment of acute gastric ulcers.

  6. Indium-111-oxine labeled platelet kinetics in patients with diabetes mellitus

    International Nuclear Information System (INIS)

    Forstrom, L.A.; Luikens, B.; Johnson, T.

    1984-01-01

    The possible role of abnormal platelet function in the pathogenesis of vascular disease in patients with diabetes mellitus remains controversial. In vitro studies have shown variable alterations in platelet function in such patients. Studies of in vivo platelet kinetics in diabetic patients have been inconclusive, although decreased platelet survival has been observed in some cases. Earlier studies were carried out using chromium-51 or selenium-75 for platelet labeling. The authors have performed Indium-111-oxine labeled platelet kinetic and biodistribution studies in 4 patients with diabetes mellitus (ages 49-61 years), and in 4 control subjects (ages 46-60 years). All subjects were male. All diabetic patients were poorly controlled at the time of study, with blood glucose > 140 mg% and hemoglobin A-1c > 10%. Autologous platelets were labeled with Indium-111-oxine in ACD:plasma by previously reported methods, and reinjected in a dose of approximately 50 μCi (range 42-67μCi). Average recovery of the injected platelets was 67% (range 41-85%). Computer analyzed images at 24 hours showed no significant difference in liver uptake between diabetic and control subjects. Mildly increased splenic uptake in diabetic patients was of borderline significance (p=.07). Platelet survival was slightly decreased in diabetic subjects by 3 of 4 models utilized (linear, exponential, multiple hit and weighted mean), although the difference achieved significance only for the weighted man model (p=.05). These data support observations by earlier methods which suggest that platelet survival may be decreased in patients with diabetes mellitus

  7. VacA, the vacuolating cytotoxin of Helicobacter pylori, binds to multimerin 1 on human platelets

    OpenAIRE

    Satoh, Kaneo; Hirayama, Toshiya; Takano, Katsuhiro; Suzuki-Inoue, Katsue; Sato, Tadashi; Ohta, Masato; Nakagomi, Junko; Ozaki, Yukio

    2013-01-01

    Platelets were activated under the infection with H. pylori in human and mice. We investigated the role of VacA, an exotoxin released by H. pylori in this context. Acid-activated VacA, but not heated VacA, induced platelet CD62P expression. However, VacA reacted with none of the alleged VacA receptors present on platelet membranes. We therefore analyzed VacA associated proteins obtained through VacA affinity chromatography, using MALDI-TOF-MS. Multimerin1 was detected in two consecutive exper...

  8. Anti-platelet activity of water dispersible curcuminoids in rat platelets.

    Science.gov (United States)

    Maheswaraiah, Anikisetty; Rao, Lingamallu Jaganmohan; Naidu, Kamatham Akhilender

    2015-03-01

    Curcuminoids are active principle of turmeric with plethora of health beneficial properties. In this study, we have evaluated for the first time the effect of water dispersible curcuminoids on rat platelet aggregation. Curcuminoids (10-30 µg/mL) significantly inhibited platelet aggregation induced by agonists viz., collagen, ADP and arachidonic acid. Curcuminoids were found to be two-fold more potent than curcumin in inhibiting platelet aggregation. Intracellular curcuminoid concentration was relatively higher than curcumin in rat platelets. Curcuminoids significantly attenuated thromboxane A2 , serotonin levels in rat platelets which play an important role in platelet aggregation. Curcuminoid treatment increased nitric oxide (NO) levels in platelets treated with agonists. Curcuminoids inhibited free radicals such as superoxide anion released from activated platelets, which ultimately inhibits platelet aggregation. Further, curcuminoids inhibited 12-lipoxygenase activity and formation of 12-hydroperoxyeicosatetraenoic acid (12-HPETE) in activated rat platelets which regulates platelet aggregation. The results suggest that curcuminoids have remarkable anti-platelet activity by modulating multiple mechanisms involved in platelet aggregation. Thus curcuminoids may have a therapeutic potential to prevent platelet activation related disorders. Copyright © 2015 John Wiley & Sons, Ltd.

  9. In vitro function of random donor platelets stored for 7 days in composol platelet additive solution

    Directory of Open Access Journals (Sweden)

    Gupta Ashish

    2011-01-01

    Full Text Available Background and Aim: Platelets are routinely isolated from whole blood and stored in plasma for 5 days. This study was done to assess the in vitro function of random donor platelets stored for 7 days in composol platelet additive solution at 22°C. Materials and Methods: The study sample included 30 blood donors of both sex in State Blood Bank, C S M Medical University, Lucknow. Random donor platelets were prepared by the platelet-rich plasma method. Whole blood (350 ml was collected in anticoagulant Citrate Phosphate Dextrose Adenine triple blood bags. Random donor platelets were stored for 7 days at 22°C in platelet incubators and agitators with and without additive solution. Results: Platelet swirling was present in all the units at 22°C on day 7 with no evidence of bacterial contamination. Comparison of the mean values of platelet count, platelet factor 3, lactate dehydrogenase, pH, glucose and platelet aggregation showed no significant difference in additive solution while platelet factor 3, glucose and platelet aggregation showed significant difference (P < 0.001 on day 7 without additive solution at 22°C. Conclusion: Our study infers that the platelet viability and aggregation were the best maintained within normal levels on day 7 of storage in platelet additive solution at 22°C. Thus, we may conclude that in vitro storage of random donor platelets with an extended shelf life of 7 days using platelet additive solution may be advocated to improve the inventory of platelets.

  10. Comparative Effects of Platelet-Rich Plasma, Platelet Lysate, and Fetal Calf Serum on Mesenchymal Stem Cells.

    Science.gov (United States)

    Lykov, A P; Bondarenko, N A; Surovtseva, M A; Kim, I I; Poveshchenko, O V; Pokushalov, E A; Konenkov, V I

    2017-10-01

    We studied the effects of human platelet-rich plasma and platelet lysate on proliferation, migration, and colony-forming properties of rat mesenchymal stem cells. Platelet-rich plasma and platelet lysate stimulated the proliferation, migration, and colony formation of mesenchymal stem cells. A real-time study showed that platelet-rich plasma produces the most potent stimulatory effect, while both platelet-rich plasma and platelet lysate stimulated migration of cells.

  11. Expression, purification and preliminary X-ray characterization of dl-2-haloacid dehalogenase from Methylobacterium sp. CPA1

    Energy Technology Data Exchange (ETDEWEB)

    Omi, Rie [Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011 (Japan); Department of Chemistry, Graduate School of Science, Osaka City University, Sumiyoshi-ku, Osaka 558-8585 (Japan); Jitsumori, Keiji; Yamauchi, Takahiro; Ichiyama, Susumu; Kurihara, Tatsuo; Esaki, Nobuyoshi [Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011 (Japan); Kamiya, Nobuo; Hirotsu, Ken, E-mail: hirotsu@sci.osaka-cu.ac.jp; Miyahara, Ikuko [Department of Chemistry, Graduate School of Science, Osaka City University, Sumiyoshi-ku, Osaka 558-8585 (Japan); Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011 (Japan)

    2007-07-01

    A recombinant form of dl-2-haloacid dehalogenase from Methylobacterium sp. CPA1 has been expressed in E. coli, purified and crystallized. The crystal belongs to space group P6{sub 3}. Diffraction data have been collected to 1.75 Å resolution. dl-2-Haloacid dehalogenase from Methylobacterium sp. CPA1 (dl-DEX Mb) is a unique enzyme that catalyzes the dehalogenation reaction without the formation of an ester intermediate. A recombinant form of dl-DEX Mb has been expressed in Escherichia coli, purified and crystallized using the hanging-drop vapour-diffusion method. The crystal belongs to the hexagonal space group P6{sub 3}, with unit-cell parameters a = b = 186.2, c = 114.4 Å. The crystals are likely to contain between four and eight monomers in the asymmetric unit, with a V{sub M} value of 4.20–2.10 Å{sup 3} Da{sup −1}. A self-rotation function revealed peaks on the χ = 180° section. X-ray data have been collected to 1.75 Å resolution.

  12. Overcoming the bottleneck of platelet lysate supply in large-scale clinical expansion of adipose-derived stem cells: A comparison of fresh versus three types of platelet lysates from outdated buffy coat-derived platelet concentrates.

    Science.gov (United States)

    Glovinski, Peter V; Herly, Mikkel; Mathiasen, Anders B; Svalgaard, Jesper D; Borup, Rehannah; Talman, Maj-Lis M; Elberg, Jens J; Kølle, Stig-Frederik T; Drzewiecki, Krzysztof T; Fischer-Nielsen, Anne

    2017-02-01

    Platelet lysates (PL) represent a promising replacement for xenogenic growth supplement for adipose-derived stem cell (ASC) expansions. However, fresh platelets from human blood donors are not clinically feasible for large-scale cell expansion based on their limited supply. Therefore, we tested PLs prepared via three methods from outdated buffy coat-derived platelet concentrates (PCs) to establish an efficient and feasible expansion of ASCs for clinical use. PLs were prepared by the freeze-thaw method from freshly drawn platelets or from outdated buffy coat-derived PCs stored in the platelet additive solution, InterSol. Three types of PLs were prepared from outdated PCs with platelets suspended in either (1) InterSol (not manipulated), (2) InterSol + supplemented with plasma or (3) plasma alone (InterSol removed). Using these PLs, we compared ASC population doubling time, cell yield, differentiation potential and cell surface markers. Gene expression profiles were analyzed using microarray assays, and growth factor concentrations in the cell culture medium were measured using enzyme-linked immunosorbent assay (ELISA). Of the three PL compositions produced from outdated PCs, removal of Intersol and resuspension in plasma prior to the first freezing process was overall the best. This specific outdated PL induced ASC growth kinetics, surface markers, plastic adherence and differentiation potentials comparable with PL from fresh platelets. ASCs expanded in PL from fresh versus outdated PCs exhibited different expressions of 17 overlapping genes, of which 10 were involved in cellular proliferation, although not significantly reflected by cell growth. Only minor differences in growth factor turnover were observed. PLs from outdated platelets may be an efficient and reliable source of human growth supplement allowing for large-scale ASC expansion for clinical use. Copyright © 2017 International Society for Cellular Therapy. Published by Elsevier Inc. All rights

  13. Thrombokinetics with In-111-oxine labelled platelets

    International Nuclear Information System (INIS)

    Uchida, Tatsumi; Yui, Tokuo; Muroi, Shuichi; Matsuda, Shin; Kariyone, Shigeo

    1982-01-01

    Indium-111-oxine has been employed as a redioactive platelet label for thrombosis imaging and thrombokinetic studies in man. To evaluate it's suitability for platelet survival and turnover, thrombokinetic studies were carried out in hematological normal subjects, in patients with idiopathic thrombocytopenic purpura (ITP) and chronic congestive splenomegaly. For In-111-oxine labelled platelets, platelets were collected by differential centrifugation from 44 ml of whole blood drawn into 6 ml of acid citrate dextrose solution. Platelet suspension was incubated with In-111-oxine, which was extracted before use by the method of Thakur and co-workers. The survival, recovery and turnover of In-111-labeled platelets were 8.6 +- 0.5 days, 63.0 +- 5.4% and 3.9 +- 0.3 x 10 4 / μl/day, respectively, which were similar with those of Cr-51 method. Platelet disappearance curves labelled with In-111 and Cr-51 simultaneously were similar in one case. In patients with ITP, platelet survival shortened in the same degree with Cr-51 method. The two simultaneous labeling studies between In-111 and Cr-51 showed no differences. In the patients with congestive splenomegaly, the same results were obtained. Thrombokinetic studies with In-111-oxine labelled platelets offer the advantages of reduced blood requirements, and the ability to perform external imaging of platelet distribution. (author)

  14. Influence of Oxidative Stress on Stored Platelets

    Directory of Open Access Journals (Sweden)

    K. Manasa

    2016-01-01

    Full Text Available Platelet storage and its availability for transfusion are limited to 5-6 days. Oxidative stress (OS is one of the causes for reduced efficacy and shelf-life of platelets. The studies on platelet storage have focused on improving the storage conditions by altering platelet storage solutions, temperature, and materials. Nevertheless, the role of OS on platelet survival during storage is still unclear. Hence, this study was conducted to investigate the influence of storage on platelets. Platelets were stored for 12 days at 22°C. OS markers such as aggregation, superoxides, reactive oxygen species, glucose, pH, lipid peroxidation, protein oxidation, and antioxidant enzymes were assessed. OS increased during storage as indicated by increments in aggregation, superoxides, pH, conjugate dienes, and superoxide dismutase and decrements in glucose and catalase. Thus, platelets could endure OS till 6 days during storage, due to the antioxidant defense system. An evident increase in OS was observed from day 8 of storage, which can diminish the platelet efficacy. The present study provides an insight into the gradual changes occurring during platelet storage. This lays the foundation towards new possibilities of employing various antioxidants as additives in storage solutions.

  15. Detection of microbial contamination in platelets

    Science.gov (United States)

    Berg, Tracy L.; Leparc, German; Huffman, Debra E.; Gennaccaro, Angela L.; Garcia-Lopez, Alicia; Klungness, Greta; Stephans, Christie; Garcia-Rubio, Luis H.

    2005-03-01

    In the United States, approximately 100 patients develop fatal sepsis associated with platelet transfusions every year. Current culture methods take 24-48 hours to acquire results, which in turn decrease the shelf life of platelets. Many of the microorganisms that contaminate platelets can replicate easily at room temperature, which is the necessary storage temperature to keep platelets functional. Therefore, there is a need for in-situ quality control assessment of the platelet quality. For this purpose, a real time spectrophotometric technique has been developed. The Spectral Acquisition Processing Detection (SAPD) method, comprised of a UV-vis spectrophotometer and modeling algorithms, is a rapid method that can be performed prior to platelet transfusion to decrease the risk of bacterial infection to patients. The SAPD method has been used to determine changes in cell suspensions, based on size, shape, chemical composition and internal structure. Changes in these cell characteristics can in turn be used to determine microbial contamination, platelet aging and other physiologic changes. Detection limits of this method for platelet suspensions seeded with bacterial contaminants were identified to be less than 100 cfu/ml of sample. Bacterial counts below 1000 cfu/ml are not considered clinically significant. The SAPD method can provide real-time identification of bacterial contamination of platelets affording patients an increased level of safety without causing undue strain on laboratory budgets or personnel while increasing the time frame that platelets can be used by dramatically shortening contaminant detection time.

  16. The role of platelets during reproduction.

    Science.gov (United States)

    Isermann, Berend; Nawroth, Peter P

    2006-01-01

    The availability of mice with defined defects within the hemostatic system enabled researchers to identify a role the coagulation system for embryonic and placental development. However, the role of platelets during development has only recently been experimentally addressed, giving some insight into potential functions of platelets during development. Thus, a quantitative embryonic platelet defect (severe thrombopenia secondary to NF-E2 deficiency) is associated with an embryonic growth retardation and reduced vascularisation of the placenta. Maternal platelet deficiency is associated with placental hemorrhage, which, however, does not impair embryonic or maternal survival. In vitro studies established that platelets or platelet conditioned medium regulate the invasive properties of human extravillous trophoblast cells and induce a phenotypical switch of trophoblast cells. These data imply that platelets are of relevance during placentation. Conversely, platelets and the formation of platelet-fibrin aggregates are dispensable for the development of the embryo proper, establishing that the lethal phenotypes observed in some embryo slacking coagulation regulators does not result from an inability to form platelet-fibrin aggregates, but likely reflects altered protease dependent signaling during vascular development.

  17. Binding of Thrombin-Activated Platelets to a Fibrin Scaffold through αIIbβ3 Evokes Phosphatidylserine Exposure on Their Cell Surface

    Science.gov (United States)

    Brzoska, Tomasz; Suzuki, Yuko; Mogami, Hideo; Sano, Hideto; Urano, Tetsumei

    2013-01-01

    Recently, by employing intra-vital confocal microscopy, we demonstrated that platelets expose phosphatidylserine (PS) and fibrin accumulate only in the center of the thrombus but not in its periphery. To address the question how exposure of platelet anionic phospholipids is regulated within the thrombus, an in-vitro experiment using diluted platelet-rich plasma was employed, in which the fibrin network was formed in the presence of platelets, and PS exposure on the platelet surface was analyzed using Confocal Laser Scanning Microscopy. Almost all platelets exposed PS after treatment with tissue factor, thrombin or ionomycin. Argatroban abrogated fibrin network formation in all samples, however, platelet PS exposure was inhibited only in tissue factor- and thrombin-treated samples but not in ionomycin-treated samples. FK633, an αIIbβ3 antagonist, and cytochalasin B impaired platelet binding to the fibrin scaffold and significantly reduced PS exposure evoked by thrombin. Gly-Pro-Arg-Pro amide abrogated not only fibrin network formation, but also PS exposure on platelets without suppressing platelet binding to fibrin/fibrinogen. These results suggest that outside-in signals in platelets generated by their binding to the rigid fibrin network are essential for PS exposure after thrombin treatment. PMID:23383331

  18. Binding of thrombin-activated platelets to a fibrin scaffold through α(IIb)β₃ evokes phosphatidylserine exposure on their cell surface.

    Science.gov (United States)

    Brzoska, Tomasz; Suzuki, Yuko; Mogami, Hideo; Sano, Hideto; Urano, Tetsumei

    2013-01-01

    Recently, by employing intra-vital confocal microscopy, we demonstrated that platelets expose phosphatidylserine (PS) and fibrin accumulate only in the center of the thrombus but not in its periphery. To address the question how exposure of platelet anionic phospholipids is regulated within the thrombus, an in-vitro experiment using diluted platelet-rich plasma was employed, in which the fibrin network was formed in the presence of platelets, and PS exposure on the platelet surface was analyzed using Confocal Laser Scanning Microscopy. Almost all platelets exposed PS after treatment with tissue factor, thrombin or ionomycin. Argatroban abrogated fibrin network formation in all samples, however, platelet PS exposure was inhibited only in tissue factor- and thrombin-treated samples but not in ionomycin-treated samples. FK633, an α(IIb)β₃ antagonist, and cytochalasin B impaired platelet binding to the fibrin scaffold and significantly reduced PS exposure evoked by thrombin. Gly-Pro-Arg-Pro amide abrogated not only fibrin network formation, but also PS exposure on platelets without suppressing platelet binding to fibrin/fibrinogen. These results suggest that outside-in signals in platelets generated by their binding to the rigid fibrin network are essential for PS exposure after thrombin treatment.

  19. Binding of thrombin-activated platelets to a fibrin scaffold through α(IIbβ₃ evokes phosphatidylserine exposure on their cell surface.

    Directory of Open Access Journals (Sweden)

    Tomasz Brzoska

    Full Text Available Recently, by employing intra-vital confocal microscopy, we demonstrated that platelets expose phosphatidylserine (PS and fibrin accumulate only in the center of the thrombus but not in its periphery. To address the question how exposure of platelet anionic phospholipids is regulated within the thrombus, an in-vitro experiment using diluted platelet-rich plasma was employed, in which the fibrin network was formed in the presence of platelets, and PS exposure on the platelet surface was analyzed using Confocal Laser Scanning Microscopy. Almost all platelets exposed PS after treatment with tissue factor, thrombin or ionomycin. Argatroban abrogated fibrin network formation in all samples, however, platelet PS exposure was inhibited only in tissue factor- and thrombin-treated samples but not in ionomycin-treated samples. FK633, an α(IIbβ₃ antagonist, and cytochalasin B impaired platelet binding to the fibrin scaffold and significantly reduced PS exposure evoked by thrombin. Gly-Pro-Arg-Pro amide abrogated not only fibrin network formation, but also PS exposure on platelets without suppressing platelet binding to fibrin/fibrinogen. These results suggest that outside-in signals in platelets generated by their binding to the rigid fibrin network are essential for PS exposure after thrombin treatment.

  20. Platelet destruction in autoimmune thrombocytopenic purpura: kinetics and clearance of indium-111-labeled autologous platelets

    International Nuclear Information System (INIS)

    Stratton, J.R.; Ballem, P.J.; Gernsheimer, T.; Cerqueira, M.; Slichter, S.J.

    1989-01-01

    Using autologous 111 In-labeled platelets, platelet kinetics and the sites of platelet destruction were assessed in 16 normal subjects (13 with and three without spleens), in 17 studies of patients with primary autoimmune thrombocytopenic purpura (AITP), in six studies of patients with secondary AITP, in ten studies of patients with AITP following splenectomy, and in five thrombocytopenic patients with myelodysplastic syndromes. In normal subjects, the spleen accounted for 24 +/- 4% of platelet destruction and the liver for 15 +/- 2%. Untreated patients with primary AITP had increased splenic destruction (40 +/- 14%, p less than 0.001) but not hepatic destruction (13 +/- 5%). Compared with untreated patients, prednisone treated patients did not have significantly different spleen and liver platelet sequestration. Patients with secondary AITP had similar platelet counts, platelet survivals, and increases in splenic destruction of platelets as did patients with primary AITP. In contrast, patients with myelodysplastic syndromes had a normal pattern of platelet destruction. In AITP patients following splenectomy, the five nonresponders all had a marked increase (greater than 45%) in liver destruction compared to five responders (all less than 40%). Among all patients with primary or secondary AITP, there was an inverse relationship between the percent of platelets destroyed in the liver plus spleen and both the platelet count (r = 0.75, p less than 0.001) and the platelet survival (r = 0.86, p less than 0.001). In a stepwise multiple linear regression analysis, total liver plus spleen platelet destruction, the platelet survival and the platelet turnover were all significant independent predictors of the platelet count. Thus platelet destruction is shifted to the spleen in primary and secondary AITP. Failure of splenectomy is associated with a marked elevation in liver destruction

  1. Are the changes in the peripheral brain-derived neurotrophic factor levels due to platelet activation?

    Science.gov (United States)

    Serra-Millàs, Montserrat

    2016-01-01

    Brain-derived neurotrophic factor (BDNF) plays an important role in central nervous system development, neurogenesis and neuronal plasticity. BDNF is also expressed in several non-neuronal tissues, and it could play an important role in other processes, such as cancer, angiogenesis, etc. Platelets are the major source of peripheral BDNF. However, platelets also contain high amounts of serotonin; they express specific surface receptors during activation, and a multitude of pro-inflammatory and immunomodulatory bioactive compounds are secreted from the granules. Until recently, there was insufficient knowledge regarding the relationship between BDNF and platelets. Recent studies showed that BDNF is present in two distinct pools in platelets, in α-granules and in the cytoplasm, and only the BDNF in the granules is secreted following stimulation, representing 30% of the total BDNF in platelets. BDNF has an important role in the pathophysiology of depression. Low levels of serum BDNF have been described in patients with major depressive disorder, and BDNF levels increased with chronic antidepressant treatment. Interestingly, there is an association between depression and platelet function. This review analyzed studies that evaluated the relationship between BDNF and platelet activation and the effect of treatments on both parameters. Only a few studies consider this possible confounding factor, and it could be very important in diseases such as depression, which show changes in both parameters. PMID:27014600

  2. The use of platelet-rich plasma to treat chronic tendinopathies: A technical analysis.

    Science.gov (United States)

    Kaux, Jean-François; Emonds-Alt, Thibault

    2018-05-01

    Platelet-rich plasma (PRP) is blood plasma with a high concentration of autologous platelets which constitute an immense reservoir of growth factors. The clinical use of PRP is widespread in various medical applications. Although highly popular with athletes, the use of PRP for the treatment of tendinopathies remains scientifically controversial, particularly due to the diversity of products that go by the name of "PRP." To optimize its use, it is important to look at the various stages of obtaining PRP. In this literature review, we take a closer look at eight parameters which may influence the quality of PRP: 1) anticoagulants used to preserve the best platelet function, 2) the speed of centrifugation used to extract the platelets, 3) the platelet concentrations obtained, 4) the impact of the concentration of red and while blood cells on PRP actions, 5) platelet activators encouraging platelet degranulation and, hence, the release of growth factors, and 6) the use or nonuse of local anesthetics when carrying out infiltration. In addition to these parameters, it may be interesting to analyze other variables such as 7) the use of ultrasound guidance during the injection with a view to determining the influence they have on potential recovery.

  3. Glycoprotein Ib activation by thrombin stimulates the energy metabolism in human platelets

    Science.gov (United States)

    Corona de la Peña, Norma; Gutiérrez-Aguilar, Manuel; Hernández-Reséndiz, Ileana; Marín-Hernández, Álvaro

    2017-01-01

    Thrombin-induced platelet activation requires substantial amounts of ATP. However, the specific contribution of each ATP-generating pathway i.e., oxidative phosphorylation (OxPhos) versus glycolysis and the biochemical mechanisms involved in the thrombin-induced activation of energy metabolism remain unclear. Here we report an integral analysis on the role of both energy pathways in human platelets activated by several agonists, and the signal transducing mechanisms associated with such activation. We found that thrombin, Trap-6, arachidonic acid, collagen, A23187, epinephrine and ADP significantly increased glycolytic flux (3–38 times vs. non-activated platelets) whereas ristocetin was ineffective. OxPhos (33 times) and mitochondrial transmembrane potential (88%) were increased only by thrombin. OxPhos was the main source of ATP in thrombin-activated platelets, whereas in platelets activated by any of the other agonists, glycolysis was the principal ATP supplier. In order to establish the biochemical mechanisms involved in the thrombin-induced OxPhos activation in platelets, several signaling pathways associated with mitochondrial activation were analyzed. Wortmannin and LY294002 (PI3K/Akt pathway inhibitors), ristocetin and heparin (GPIb inhibitors) as well as resveratrol, ATP (calcium-release inhibitors) and PP1 (Tyr-phosphorylation inhibitor) prevented the thrombin-induced platelet activation. These results suggest that thrombin activates OxPhos and glycolysis through GPIb-dependent signaling involving PI3K and Akt activation, calcium mobilization and protein phosphorylation. PMID:28817667

  4. Indium-111 platelet imaging for detection of platelet deposition in abdominal aneurysms and prosthetic arterial grafts

    International Nuclear Information System (INIS)

    Ritchie, J.L.; Stratton, J.R.; Thiele, B.; Haminton, G.W.; Warrick, L.N.; Huang, T.W.; Harker, L.A.

    1981-01-01

    Thirty-four platelet imaging studies were performed in 23 patients to determine whether platelet deposition could be detected in patients with vascular aneurysms (18 patients) or in patients in whom Dacron prosthetic grafts had been placed (5 patients). In patients in whom abnormal platelet deposition was detected, the effect of administration of platelet-active drugs on platelet deposition was examined. Of the 18 patients with an aneurysm, 12 had equivocally positive studies on initial imaging and 2 had equivocally positive images. Of five patients with Dacron arterial grafts in place, four had diffuse platelet deposition in the grafts; the fifth patient had a platelet deposition only in a pseudoaneurysm. Eight patients with an abdominal aneurysm and positive or equivocally positive baseline images were restudied during platelet-active drug therapy either with aspirin plus dipyridamole (seven patients) or with sulfinpyrazone (four patients). No patient studied during treatment with aspirin plus dipyridamole had detectably decreased platelet deposition compared with baseline determinations. In contrast, two of four patients studied while receiving sulfinpyrazone showed decreased platelet deposition. Thus, platelet imaging may be of value for studying platelet physiology in vivo and for assessing platelet-active drugs and the thrombogenicity of prosthetic graft materials in human beings

  5. The role of 5-hydroxytryptophan (5-HTP) in the regulation of the sleep/wake cycle in parachlorophenylalanine (p-CPA) pretreated rat: a multiple approach study.

    Science.gov (United States)

    Touret, M; Sarda, N; Gharib, A; Geffard, M; Jouvet, M

    1991-01-01

    In the rat, the insomnia which follows the administration of parachlorophenylalanine (p-CPA), a serotonin synthesis inhibitor, is transiently reversed either by intra-cisternal injection of L-5-HTP or by an associated injection of 5-HTP and an L-aromatic-acid-decarboxylase inhibitor (benserazide). Histochemical, immunohistochemical and chemical investigations showed that 5-HTP administration does not lead to a detectable increase in cerebral 5-HT. These findings suggest that the restoration of sleep after p-CPA treatment could be mediated by the central action of 5-HTP.

  6. OP9 bone marrow stroma cells differentiate into megakaryocytes and platelets.

    Directory of Open Access Journals (Sweden)

    Yumiko Matsubara

    Full Text Available Platelets are essential for hemostatic plug formation and thrombosis. The mechanisms of megakaryocyte (MK differentiation and subsequent platelet production from stem cells remain only partially understood. The manufacture of megakaryocytes (MKs and platelets from cell sources including hematopoietic stem cells and pluripotent stem cells have been highlighted for studying the platelet production mechanisms as well as for the development of new strategies for platelet transfusion. The mouse bone marrow stroma cell line OP9 has been widely used as feeder cells for the differentiation of stem cells into MK lineages. OP9 cells are reported to be pre-adipocytes. We previously reported that 3T3-L1 pre-adipocytes differentiated into MKs and platelets. In the present study, we examined whether OP9 cells differentiate into MKs and platelets using MK lineage induction (MKLI medium previously established to generate MKs and platelets from hematopoietic stem cells, embryonic stem cells, and pre-adipocytes. OP9 cells cultured in MKLI medium had megakaryocytic features, i.e., positivity for surface markers CD41 and CD42b, polyploidy, and distinct morphology. The OP9-derived platelets had functional characteristics, providing the first evidence for the differentiation of OP9 cells into MKs and platelets. We then analyzed gene expressions of critical factors that regulate megakaryopoiesis and thrombopoiesis. The gene expressions of p45NF-E2, FOG, Fli1, GATA2, RUNX1, thrombopoietin, and c-mpl were observed during the MK differentiation. Among the observed transcription factors of MK lineages, p45NF-E2 expression was increased during differentiation. We further studied MK and platelet generation using p45NF-E2-overexpressing OP9 cells. OP9 cells transfected with p45NF-E2 had enhanced production of MKs and platelets. Our findings revealed that OP9 cells differentiated into MKs and platelets in vitro. OP9 cells have critical factors for megakaryopoiesis and

  7. Platelet-Released Growth Factors Induce Differentiation of Primary Keratinocytes

    OpenAIRE

    Bayer, Andreas; Tohidnezhad, Mersedeh; Lammel, Justus; Lippross, Sebastian; Behrendt, Peter; Klüter, Tim; Pufe, Thomas; Jahr, Holger; Cremer, Jochen; Rademacher, Franziska; Gläser, Regine; Harder, Jürgen

    2017-01-01

    Autologous thrombocyte concentrate lysates, for example, platelet-released growth factors, (PRGFs) or their clinically related formulations (e.g., Vivostat PRF?) came recently into the physicians' focus as they revealed promising effects in regenerative and reparative medicine such as the support of healing of chronic wounds. To elucidate the underlying mechanisms, we analyzed the influence of PRGF and Vivostat PRF on human keratinocyte differentiation in vitro and on epidermal differentiatio...

  8. Platelet indices and platelet-to-lymphocyte ratio predict coronary chronic total occlusion in patients with acute ST-elevation myocardial infarction

    Directory of Open Access Journals (Sweden)

    Hadadi Laszlo

    2015-12-01

    Full Text Available Coronary chronic total occlusion (CTO is caused by organized thrombi or atherosclerotic plaque progression. The presence of a CTO is an independent predictor of mortality in patients presenting with ST-segment elevation myocardial infarction (STEMI. Platelets have a crucial role in the pathophysiology of atherosclerosis. The aim of this retrospective study was to investigate platelet indices as predictors of CTO in patients with STEMI treated with primary percutaneous coronary intervention (pPCI. A total number of 334 patients admitted for STEMI between January 2011 and December 2013 were included and divided in two groups based on the presence of CTO (48 patients in CTO+ group, 286 patients in CTO-group. Platelet count, mean platelet volume (MPV, platelet distribution width (PDW, platelet-large cell ratio (P-LCR, lymphocyte and neutrophil count determined on admission were analyzed. MPV was larger in patients with CTO compared with patients without CTO (p=0.02, as were PDW (p=0.03 and P-LCR (p=0.01. Platelet-to-lymphocyte ratio (PLT/LYM was lower in patients with CTO: 105.2 (75.86-159.1 compared to 137 (97-188.1, p<0.01. Receiver-operator characteristic curve analysis identified an area under the curve of 0.61 (95%CI=0.57-0.67, p< 0.01 for PLT/LYM in predicting the presence of a CTO, with a cut-off value at 97.73. Lower values than this were independent predictors of a CTO in multivariate logistic regression analysis, with an Odds Ratio of 2.2 (95%CI=1.15-4.20, p=0.02. Our results support the use of platelet indices and PLT/LYM as predictors of CTO in patients presenting with STEMI.

  9. Therapeutic platelet reduction: Use in postsplenectomy thrombocytosis

    Directory of Open Access Journals (Sweden)

    Gita Negi

    2015-01-01

    Full Text Available Therapeutic platelet reduction is an effective modality for the reduction of platelet count in patients with treatment of extreme thrombocytosis resulting from a variety of primary and secondary causes of thrombocytosis, which may be associated with thrombotic or hemorrhagic complications of varying degrees. These cases when symptomatic fall into the ASFA Category II indication for therapeutic platelet apheresis procedure. Here, we report a case of postsplenectomy secondary thrombocytosis presenting with extremely high platelet counts and subsequent thrombosis in the shunt and successful treatment after therapeutic platelet reduction. The case is being presented to bring forth the fact that therapeutic platelet reduction is an easy procedure that gives quick and good results and also to bring to the attention of transfusion specialists an associated but as yet unreported procedural finding.

  10. A recently developed bifacial platelet-rich fibrin matrix

    Directory of Open Access Journals (Sweden)

    E Lucarelli

    2010-07-01

    Full Text Available Platelet-rich plasma (PRP is used clinically in liquid or gel form to promote tissue repair. Because of the poor mechanical properties, conventional PRP is often difficult to handle when used in clinical settings and requires secure implantation in a specific site, otherwise when released growth factors could be washed out during an operation. In this study, we analyzed the end product of a recently developed commercially available system (FIBRINET®, which is a dense pliable, platelet-rich fibrin matrix (PRFM. We characterized the mechanical properties of PRFM and tested whether PRFM releases growth factors and whether released factors induce the proliferation of mesenchymal stem cells (MSC. Mechanical properties as well as platelet distribution were evaluated in PRFM. PRFM demonstrated robust mechanical properties, with a tear elastic modulus of 937.3 + 314.6 kPa, stress at a break of 1476.0 + 526.3 kPa, and an elongation at break of 146.3 + 33.8 %. PRFM maintained its mechanical properties throughout the testing process. Microscopic observations showed that the platelets were localized on one side of the matrix. Elevated levels of PDGF-AA, PDGF-AB, EGF, VEGF, bFGF and TGF-β1 were measured in the day 1-conditioned media (CM of PRFM and growth factor levels decreased thereafter. BMP2 and BMP7 were not detectable. MSC culture media supplemented with 20% PRFM-CM stimulated MSC cell proliferation; at 24 and 48 hours the induction of the proliferation was significantly greater than the induction obtained with media supplemented with 20% foetal bovine serum. The present study shows that the production of a dense, physically robust PRFM made through high-speed centrifugation of intact platelets and fibrin in the absence of exogenous thrombin yields a potential tool for accelerating tissue repair.

  11. LDL oxidation by platelets propagates platelet activation via an oxidative stress-mediated mechanism.

    Science.gov (United States)

    Carnevale, Roberto; Bartimoccia, Simona; Nocella, Cristina; Di Santo, Serena; Loffredo, Lorenzo; Illuminati, Giulio; Lombardi, Elisabetta; Boz, Valentina; Del Ben, Maria; De Marco, Luigi; Pignatelli, Pasquale; Violi, Francesco

    2014-11-01

    Platelets generate oxidized LDL (ox-LDL) via NOX2-derived oxidative stress. We investigated if once generated by activated platelets ox-LDL can propagate platelet activation. Experiments were performed in platelets from healthy subjects (HS), hyper-cholesterolemic patients and patients with NOX2 hereditary deficiency. Agonist-stimulated platelets from HS added with LDL were associated with a dose-dependent increase of reactive oxidant species and ox-LDL. Agonist-stimulated platelets from HS added with a fixed dose of LDL (57.14 μmol/L) or added with homogenized human atherosclerotic plaque showed enhanced ox-LDL formation (approximately +50% and +30% respectively), which was lowered by a NOX2 inhibitor (approximately -35% and -25% respectively). Compared to HS, ox-LDL production was more pronounced in agonist-stimulated platelet rich plasma (PRP) from hyper-cholesterolemic patients but was almost absent in PRP from NOX2-deficient patients. Platelet aggregation and 8-iso-PGF2α-ΙΙΙ formation increased in LDL-treated washed platelets (+42% and +53% respectively) and PRP (+31% and +53% respectively). Also, LDL enhanced platelet-dependent thrombosis at arterial shear rate (+33%) but did not affect platelet activation in NOX2-deficient patients. Platelet activation by LDL was significantly inhibited by CD36 or LOX1 blocking peptides, two ox-LDL receptor antagonists, or by a NOX2 inhibitor. LDL-added platelets showed increased p38MAPK (+59%) and PKC (+51%) phosphorylation, p47(phox) translocation to platelet membrane (+34%) and NOX2 activation (+30%), which were inhibited by ox-LDL receptor antagonists. Platelets oxidize LDL, which in turn amplify platelet activation via specific ox-LDL receptors; both effects are mediated by NOX2 activation. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  12. Extending The Shelf Life Of Blood Platelets

    Science.gov (United States)

    Surgenor, Douglas M.

    1988-01-01

    New method of storing human blood platelets extends vitality for transfusions. Packaged as suspension in sterile liquid in plastic blood bags. Each bag placed between pair of plastic grids, and rubberbands placed around sandwich thus formed to hold together. Stored upright in open air or in container through which air pumped at rate of at least 45 L/min. Ensures that platelets receive ample oxygen and expiratory carbon dioxide form platelets removed before pH drops to harmful levels.

  13. Platelet Glycoprotein lb-1X and Malignancy

    Science.gov (United States)

    2011-09-01

    initiate coagulation, resulting in the formation of a fibrin - rich tumor cell- platelet emboli (Figure 1). Many of these coagulation factor-tumor cell...the tumor cell in a fibrin - rich web. (13;23;24) During this process, the platelet integrin receptor, aIIb 3, serves as a receptor linking fibrin ... platelets , and tumor cells into a fibrin rich clot normally associated with a thrombus. (25;25) Indeed, it can be speculated the fibrin - rich clot

  14. Platelet aggregation and quality control of platelet concentrates produced in the Amazon Blood Bank

    Directory of Open Access Journals (Sweden)

    Maria José Dantas Coêlho

    2011-01-01

    Full Text Available BACKGROUND: The study of platelet aggregation is essential to assess in vitro platelet function by different platelet activation pathways. OBJECTIVE: To assess aggregation and biochemical parameters of random platelet concentrates produced at the Fundação HEMOAM using the quality control tests defined by law. METHODS: Whole blood samples from 80 donors and the respective platelet concentrate units were tested. Platelet concentrates were tested (platelet count, aggregation and pH on days 1, 3 and 5 of storage. Additionally a leukocyte count was done only on day 1 and microbiological tests on day 5 of storage. Collagen and adenosine diphosphate were used as inducing agonists for platelet aggregation testing. RESULTS: Donor whole blood had normal aggregation (aggregation with adenosine diphosphate = 67% and with collagen = 78%. The median aggregation in platelet concentrates with adenosine diphosphate was low throughout storage (18% on day 1, 7% on day 3 and 6% on day 5 and the median aggregation with collagen was normal only on day 1 and low thereafter (54.4% on day 1, 20.5% on day 3 and 9% on day 5. CONCLUSION: Although the results were within the norms required by law, platelet concentrates had low aggregation rates. We suggest the inclusion of a functional assessment test for the quality control of platelet concentrates for a more effective response to platelet replacement therapy.

  15. Supporting the potential of quantitative ultrasonic techniques for the evaluation of platelet concentration

    Science.gov (United States)

    Villamarín, J. A.; Jiménez, Y. M.; Molano, L. Tatiana; Gutierrez, W. Edgar; Londoño, L. Fernando; Gutierrez, D. A.

    2017-11-01

    This article describes the results obtained by making use of a non-destructive, non-invasive ultrasonic system for the acoustic characterization of bovine plasma rich in platelets using digital signal processing techniques. This study includes computational methods based on acoustic spectrometry estimation and experimental measurements of the speed of sound in blood plasma from different samples analyzed, using an ultrasonic field with resonance frequency of 5 MHz. The results showed that the measurements on ultrasonic signals can contribute to the hematological predictions based on the linear regression model applied to the relationship between experimental ultrasonic parameters calculated and platelet concentration, indicating a growth rate of 1 m/s for each 0.90 x103 platelet per mm3. On the other hand, the attenuation coefficient presented changes of 20% in the platelet concentration using a resolution of 0.057 dB/cm MHz.

  16. Comparison platelet indices in diabetic patients with and without diabetic foot ulcer

    Science.gov (United States)

    Mardia, A. I.; Gatot, D.; Lindarto, D.

    2018-03-01

    Diabetes Mellitus is a group of metabolic disease which incidence increases every year. Some diabetic patients have diabetic foot ulcer as acomplication. The occurrence of ulcers in diabetic patients can be caused by the presence of thrombosis due to increased platelet function. Therefore, a cross-sectional study on 40 diabetic patients was performed at RSUP Adam Malik Medan to see whether there were differences in platelet indices between diabetic patients with and without diabetic foot ulcers. Platelets indices were examined and looked for differences in diabetic patients with and without diabetic foot ulcers. Data were analyzed using Chi-Square and Mann-Whitney U test with 95% CI. P-valuediabetic patients with diabetic foot ulcers indicating more reactive and aggregatable platelet function.

  17. Haplotype of platelet receptor P2RY12 gene is associated with residual clopidogrel on-treatment platelet reactivity.

    Science.gov (United States)

    Nie, Xiao-Yan; Li, Jun-Lei; Zhang, Yong; Xu, Yang; Yang, Xue-Li; Fu, Yu; Liang, Guang-Kai; Lu, Yun; Liu, Jian; Shi, Lu-Wen

    To investigate a possible association between common variations of the P2RY12 and the residual clopidogrel on-treatment platelet reactivity after adjusting for the influence of CYP2C19 tested by thromboelastography (TEG). One hundred and eighty patients with acute coronary syndrome (ACS) treated with clopidogrel and aspirin were included and platelet function was assessed by TEG. Five selected P2RY12 single nucleotide polymorphisms (SNPs; rs6798347, rs6787801, rs6801273, rs6785930, and rs2046934), which cover the common variations in the P2RY12 gene and its regulatory regions, and three CYP2C19 SNPs ( * 2, * 3, * 17) were genotyped and possible haplotypes were analyzed. The high on-treatment platelet reactivity (HTPR) prevalence defined by a platelet inhibition rate <30% by TEG in adenosine diphosphate (ADP)-channel was 69 (38.33%). Six common haplotypes were inferred from four of the selected P2RY12 SNPs (denoted H 0 to H 5 ) according to the linkage disequilibrium R square (except for rs2046934). Haplotype H 1 showed a significantly lower incidence of HTPR than the reference haplotype (H 0 ) in the total study population while haplotypes H 1 and H 2 showed significantly lower incidences of HTPR than H 0 in the nonsmoker subgroup after adjusting for CYP2C19 effects and demographic characteristics. rs2046934 (T744C) did not show any significant association with HTPR. The combination of common P2RY12 variations including regulatory regions rather than rs2046934 (T744C) that related to pharmacodynamics of clopidogrel in patients with ACS was independently associated with residual on-clopidogrel platelet reactivity. This is apart from the established association of the CYP2C19. This association seemed more important in the subgroup defined by smoking.

  18. Proteomics of apheresis platelet supernatants during routine storage: Gender-related differences.

    Science.gov (United States)

    Dzieciatkowska, Monika; D'Alessandro, Angelo; Burke, Timothy A; Kelher, Marguerite R; Moore, Ernest E; Banerjee, Anirban; Silliman, Christopher C; West, Bernadette F; Hansen, Kirk C

    2015-01-01

    Proteomics has identified potential pathways involved in platelet storage lesions, which correlate with untoward effects in the recipient, including febrile non-haemolytic reactions. We hypothesize that an additional pathway involves protein mediators that accumulate in the platelet supernatants during routine storage in a donor gender-specific fashion. Apheresis platelet concentrates were collected from 5 healthy males and 5 females and routinely stored. The 14 most abundant plasma proteins were removed and the supernatant proteins from days 1 and 5 were analyzed via 1D-SDS-PAGE/nanoLC-MS/MS, before label-free quantitative proteomics analyses. Findings from a subset of 18 proteins were validated via LC-SRM analyses against stable isotope labeled standards. A total of 503 distinct proteins were detected in the platelet supernatants from the 4 sample groups: female or male donor platelets, either at storage day 1 or 5. Proteomics suggested a storage and gender-dependent impairment of blood coagulation mediators, pro-inflammatory complement components and cytokines, energy and redox metabolic enzymes. The supernatants from female donors demonstrated increased deregulation of structural proteins, extracellular matrix proteins and focal adhesion proteins, possibly indicating storage-dependent platelet activation. Routine storage of platelet concentrates induces changes in the supernatant proteome, which may have effects on the transfused patient, some of which are related to donor gender. The rationale behind this study is that protein components in platelet releasates have been increasingly observed to play a key role in adverse events and impaired homeostasis in transfused recipients. In this view, proteomics has recently emerged as a functional tool to address the issue of protein composition of platelet releasates from buffy coat-derived platelet concentrates in the blood bank. Despite early encouraging studies on buffy coat-derived platelet concentrates, platelet

  19. Modeling Phase Equilibria for Acid Gas Mixtures Using the CPA Equation of State. I. Mixtures with H2S

    DEFF Research Database (Denmark)

    Tsivintzelis, Ioannis; Kontogeorgis, Georgios; Michelsen, Michael Locht

    2010-01-01

    (water, methanol, and glycols) are modeled assuming presence or not of cross-association interactions. Such interactions are accounted for using either a combining rule or a cross-solvation energy obtained from spectroscopic data. Using the parameters obtained from the binary systems, one ternary......The Cubic-Plus-Association (CPA) equation of state is applied to a large variety of mixtures containing H2S, which are of interest in the oil and gas industry. Binary H2S mixtures with alkanes, CO2, water, methanol, and glycols are first considered. The interactions of H2S with polar compounds...... and three quaternary mixtures are considered. It is shown that overall excellent correlation for binary, mixtures and satisfactory prediction results for multicomponent systems are obtained. There are significant differences between the various modeling approaches and the best results are obtained when...

  20. KKR-CPA calculations of density of states and soft X-ray emission from disordered Li-Mg alloys

    International Nuclear Information System (INIS)

    Rajput, S.S.; Singru, R.M.; Prasad, R.

    1994-01-01

    The density of states (DOS) and soft X-ray spectra from disordered Li 1-x Mg x alloys have been calculated by using the charge self-consistent KKR-CPA method. We find that the DOS at the Fermi energy (E F ) shows an interesting behaviour as a function of x; it first increases in the range x=0.0 to 0.14, then shows a flat behaviour in the range x approx. 0.14 to 0.20 and finally decreases smoothly from x=0.20 to 0.60. We show that this behaviour of the DOS is related to the development of a neck in the Fermi surface and its smearing due to disorder scattering. Theoretical results for the soft X-ray emission spectra are compared with experimental results and are found to be in good accord. (author). 14 refs, 4 figs, 1 tab

  1. Platelet Counts in Insoluble Platelet-Rich Fibrin Clots: A Direct Method for Accurate Determination

    Directory of Open Access Journals (Sweden)

    Yutaka Kitamura

    2018-02-01

    Full Text Available Platelet-rich fibrin (PRF clots have been used in regenerative dentistry most often, with the assumption that growth factor levels are concentrated in proportion to the platelet concentration. Platelet counts in PRF are generally determined indirectly by platelet counting in other liquid fractions. This study shows a method for direct estimation of platelet counts in PRF. To validate this method by determination of the recovery rate, whole-blood samples were obtained with an anticoagulant from healthy donors, and platelet-rich plasma (PRP fractions were clotted with CaCl2 by centrifugation and digested with tissue-plasminogen activator. Platelet counts were estimated before clotting and after digestion using an automatic hemocytometer. The method was then tested on PRF clots. The quality of platelets was examined by scanning electron microscopy and flow cytometry. In PRP-derived fibrin matrices, the recovery rate of platelets and white blood cells was 91.6 and 74.6%, respectively, after 24 h of digestion. In PRF clots associated with small and large red thrombi, platelet counts were 92.6 and 67.2% of the respective total platelet counts. These findings suggest that our direct method is sufficient for estimating the number of platelets trapped in an insoluble fibrin matrix and for determining that platelets are distributed in PRF clots and red thrombi roughly in proportion to their individual volumes. Therefore, we propose this direct digestion method for more accurate estimation of platelet counts in most types of platelet-enriched fibrin matrix.

  2. Application of the cubic-plus-association (CPA) equation of state to model the fluid phase behaviour of binary mixtures of water and tetrahydrofuran

    DEFF Research Database (Denmark)

    Herslund, Peter Jørgensen; Thomsen, Kaj; Abildskov, Jens

    2013-01-01

    The complex fluid phase behaviour, of the binary system comprised of water and tetrahydrofuran (THF) is modelled by use of the cubic-plus-association (CPA) equation of state. A total of seven modelling approaches are analysed, differing only in their way of describing THF and its interactions...

  3. Modeling of Asphaltene Onset Precipitation Conditions with Cubic Plus Association (CPA) and Perturbed Chain Statistical Associating Fluid Theory (PC-SAFT) Equations of State

    DEFF Research Database (Denmark)

    Arya, Alay; Liang, Xiaodong; von Solms, Nicolas

    2016-01-01

    using various equations of state and empirical models. In the past few years, association models based on CPA and SAFT equations of state have been found to be promising models for studies of asphaltene precipitation. In this work, we compare asphaltene precipitation results obtained from different...

  4. The Effects of the 150-Credit-Hour Requirement for the Certified Public Accountant (CPA) Exam On the Career Intentions of Women and Minorities

    Science.gov (United States)

    Bierstaker, James Lloyd; Howe, Martha A.; Seol, Inshik

    2005-01-01

    In most states, students who sit for the certified public accountant (CPA) examination are now required to have 150 credit hours of college education. In this article, the authors examined the effects of this requirement on the career intentions of women and minorities. The authors collected data from 600 accounting students and the results…

  5. Evaluation of the PC-SAFT, SAFT and CPA equations of state in predicting derivative properties of selected non-polar and hydrogen-bonding compounds

    DEFF Research Database (Denmark)

    de Villiers, A.J.; Schwarz, C.E.; Burger, A.J.

    2013-01-01

    -temperature derivative. For 1-alcohols, both CPA and PC-SAFT accurately predict the isobaric heat capacity when modelled with the 3B association scheme, while SAFT is unable to capture the singularities present in the property irrespective of the association scheme used. None of the models are able to predict the speed...

  6. Platelet-rich plasma preparation for regenerative medicine: optimization and quantification of cytokines and growth factors

    Science.gov (United States)

    2013-01-01

    Introduction Platelet-rich plasma (PRP) is nowadays widely applied in different clinical scenarios, such as orthopedics, ophthalmology and healing therapies, as a growth factor pool for improving tissue regeneration. Studies into its clinical efficiency are not conclusive and one of the main reasons for this is that different PRP preparations are used, eliciting different responses that cannot be compared. Platelet quantification and the growth factor content definition must be defined in order to understand molecular mechanisms behind PRP regenerative strength. Standardization of PRP preparations is thus urgently needed. Methods PRP was prepared by centrifugation varying the relative centrifugal force, temperature, and time. Having quantified platelet recovery and yield, the two-step procedure that rendered the highest output was chosen and further analyzed. Cytokine content was determined in different fractions obtained throughout the whole centrifugation procedure. Results Our method showed reproducibility when applied to different blood donors. We recovered 46.9 to 69.5% of total initial platelets and the procedure resulted in a 5.4-fold to 7.3-fold increase in platelet concentration (1.4 × 106 to 1.9 × 106 platelets/μl). Platelets were highly purified, because only blood cells and leukocytes was present in the final PRP preparation. We also quantified growth factors, cytokines and chemokines secreted by the concentrated platelets after activation with calcium and calcium/thrombin. High concentrations of platelet-derived growth factor, endothelial growth factor and transforming growth factor (TGF) were secreted, together with the anti-inflammatory and proinflammatory cytokines interleukin (IL)-4, IL-8, IL-13, IL-17, tumor necrosis factor (TNF)-α and interferon (IFN)-α. No cytokines were secreted before platelet activation. TGF-β3 and IFNγ were not detected in any studied fraction. Clots obtained after platelet coagulation retained a high concentration of

  7. Platelet-rich plasma preparation for regenerative medicine: optimization and quantification of cytokines and growth factors.

    Science.gov (United States)

    Amable, Paola Romina; Carias, Rosana Bizon Vieira; Teixeira, Marcus Vinicius Telles; da Cruz Pacheco, Italo; Corrêa do Amaral, Ronaldo José Farias; Granjeiro, José Mauro; Borojevic, Radovan

    2013-06-07

    Platelet-rich plasma (PRP) is nowadays widely applied in different clinical scenarios, such as orthopedics, ophthalmology and healing therapies, as a growth factor pool for improving tissue regeneration. Studies into its clinical efficiency are not conclusive and one of the main reasons for this is that different PRP preparations are used, eliciting different responses that cannot be compared. Platelet quantification and the growth factor content definition must be defined in order to understand molecular mechanisms behind PRP regenerative strength. Standardization of PRP preparations is thus urgently needed. PRP was prepared by centrifugation varying the relative centrifugal force, temperature, and time. Having quantified platelet recovery and yield, the two-step procedure that rendered the highest output was chosen and further analyzed. Cytokine content was determined in different fractions obtained throughout the whole centrifugation procedure. Our method showed reproducibility when applied to different blood donors. We recovered 46.9 to 69.5% of total initial platelets and the procedure resulted in a 5.4-fold to 7.3-fold increase in platelet concentration (1.4 × 10(6) to 1.9 × 10(6) platelets/μl). Platelets were highly purified, because only platelets after activation with calcium and calcium/thrombin. High concentrations of platelet-derived growth factor, endothelial growth factor and transforming growth factor (TGF) were secreted, together with the anti-inflammatory and proinflammatory cytokines interleukin (IL)-4, IL-8, IL-13, IL-17, tumor necrosis factor (TNF)-α and interferon (IFN)-α. No cytokines were secreted before platelet activation. TGF-β3 and IFNγ were not detected in any studied fraction. Clots obtained after platelet coagulation retained a high concentration of several growth factors, including platelet-derived growth factor and TGF. Our study resulted in a consistent PRP preparation method that yielded a cytokine and growth factor pool

  8. Experimental measurement of phase equilibrium for gas hydrates of refrigerants, and thermodynamic modeling by SRK, VPT and CPA EOSs

    International Nuclear Information System (INIS)

    Karamoddin, Maryam; Varaminian, Farshad

    2013-01-01

    Highlights: • Three-phase equilibrium data, (VL W H), were measured for HCFC22 and HFC134a hydrates. • The pressures were evaluated by simple EoSs (modified mixing rule) and CPA EOS. • The Kihara potential parameters were obtained by optimizing scheme for refrigerants. -- Abstract: In this study, three-phase equilibrium conditions of hydrate-liquid–vapor, (VL W H), were experimentally determined for chlorodifluoromethane and 1,1,1,2-tetrafluoroethane gas hydrates at temperatures ranging from (278 to 290) K and (280 to 285) K respectively, at pressures ranging from (0.2 to 0.8) MPa. Then the different models were presented for estimating of the hydrate dissociation conditions of chlorodifluoromethane, 1,1,1,2-tetrafluoroethane and 1,1-difluoroethane refrigerants. The cubic simple equations of state (SRK and VPT) and the cubic plus association equation of state (CPA) were employed for modeling the vapor and liquid phases, also van der Waals–Platteeuw statistical model was used for the solid hydrate phase. In this paper, the binary interaction parameters of classic and modified mixing rules were optimized by using two-phase equilibrium data (VL W H). The Kihara potential parameters in each refrigerant were estimated using obtained experimental equilibrium data (VL W H) and based on the optimization scheme by the Nelder Mead optimization method. The agreement between the experimental and the predicted pressure is acceptable by using these models. The average deviation of models for chlorodifluoromethane, 1,1,1,2-tetrafluoroethane, and 1,1-difluoroethane hydrates is about 3%, 4.3%, and 3.6%, respectively

  9. Platelet function in the postprandial period

    Directory of Open Access Journals (Sweden)

    Sinzinger Helmut

    2012-09-01

    Full Text Available Abstract Background Postprandial hyperlipidemia and hyperglycemia have been related to cardiovascular events. Among different underlying mechanisms platelet activation seems to be responsible too. No comparable data between various tests in normo- vs. hyperlipidemics before and at different time intervals are available after a fat meal. We aimed to compare 9 of them within the same patients at several time points in postprandial hyperlipidemia. Results For some tests baseline values between the groups were significantly different (TXB2, platelet sensitivity, sedimentation and WU-test. However, hyperlipidemia revealed a variable influence on the tests examined. Some of the available tests apparently sensitive to show platelet activation reflect the increase in triglycerides (TG, such as the sedimentation index. ADP-induced platelet aggregatory activity in count adjusted washed isolated platelet samples during postprandial hyperlipidemia indicates mildly enhanced platelet activity, but does not seem to induce significant changes in aggregation. In patients with severe hypertriglyceridemia (> 400 mg/dl fasting changes in platelet function are more pronounced due to delayed decay and may last up to 16 hours paralleling TG reaching the prevalue. The overwhelming majority of platelet function tests do not significantly respond to postprandial hyperlipidemia. The correlation between the tests applied is poor. For standardization purpose, platelet aggregation tests, aimed to examine proaggregatory capacity in atherosclerosis, should only be performed at the same time of the day after a fasting period > 6 hours. The great variation in preanalytical work-up on comparison of various tests, large number of platelet tests available and their respective potential value are discussed. Conclusions At present, the suspicion that platelet function is significantly activated in the postprandial period cannot be supported by any of the tests used. The

  10. Platelet activation in pregnancy-induced hypertension.

    Science.gov (United States)

    Karalis, Ioannis; Nadar, Sunil K; Al Yemeni, Eman; Blann, Andrew D; Lip, Gregory Y H

    2005-01-01

    Although excess platelet activation, as indicated by increased plasma beta thromboglobulin (beta-TG), has been shown in pregnancy-induced hypertension (PIH), platelet adhesion, platelet morphology and a comparison of platelet and soluble (plasma) levels of the adhesion molecules P-selectin (pPsel and sPsel, respectively) have not been studied. We conducted a cross-sectional study of 35 consecutive women with PIH (age 31+/-6 years), 31 consecutive women with normotensive pregnancies (age 29+/-5 years) and 30 normotensive non pregnant women (age 30+/-5 years). Platelet adhesion was studied in vitro by binding to fibrinogen-coated microwells, platelet morphology [mass and volume by flow cytometry], whole-platelet P-selectin (pPsel) by ELISA of the lysate of 2 x 10(8) cells, and the plasma markers soluble P-selectin (sP-sel) and beta-TG, by ELISA. The women with PIH had significantly raised sPsel, pPsel and (as expected) beta-TG (all p<0.05), when compared to the normotensive pregnant women and controls. However, in PIH platelet adhesion was similar to that in the normotensive pregnancy, but still higher than the normal controls (p<0.001). There was no difference among the three groups with respect to platelet mass and volume. pPsel and platelet adhesion correlated with gestational age and with systolic and diastolic blood pressure (all p<0.05). Increased platelet activation and adhesion develop during normal pregnancy, with some indices being further altered in PIH.

  11. Reference intervals for platelet aggregation assessed by multiple electrode platelet aggregometry

    DEFF Research Database (Denmark)

    Rubak, Peter; Villadsen, Kirsten; Hvas, Anne-Mette

    2012-01-01

    Abstract Introduction Analyses of platelet aggregation in hirudin whole blood using Multiplate® was validated. Reference intervals for the most commonly used agonists were established, and the association between platelet aggregation, age, gender and haematological values was analysed. Material...... and methods We included 121 healthy individuals to establish reference intervals and six healthy individuals for evaluation of the day-to-day variation. Platelet aggregation was evaluated on hirudin whole blood employing Multiplate® induced by arachidonic acid, ADP, collagen and ristocetin (RISTOlow...... after adjusting for age and gender except for RISTOhigh. A positive significant association was found between platelet count and platelet aggregation (p

  12. Platelet-rich fibrin: Evolution of a second-generation platelet concentrate

    Directory of Open Access Journals (Sweden)

    Sunitha Raja V

    2008-01-01

    Full Text Available Platelet-rich plasma (PRP is a platelet concentrate that has been used widely to accelerate soft-tissue and hard-tissue healing. The preparation of PRP has been described by several authors. Platelet-rich fibrin (PRF was first described by Choukroun et al. in France. It has been referred to as a second-generation platelet concentrate, which has been shown to have several advantages over traditionally prepared PRP. Its chief advantages include ease of preparation and lack of biochemical handling of blood, which makes this preparation strictly autologous. This article describes the evolution of this novel platelet concentrate, referred to as PRF.

  13. Platelets promote osteosarcoma cell growth through activation of the platelet-derived growth factor receptor-Akt signaling axis

    OpenAIRE

    Takagi, Satoshi; Takemoto, Ai; Takami, Miho; Oh-hara, Tomoko; Fujita, Naoya

    2014-01-01

    The interactions of tumor cells with platelets contribute to the progression of tumor malignancy, and the expression levels of platelet aggregation-inducing factors positively correlate with the metastatic potential of osteosarcoma cells. However, it is unclear how tumor-platelet interaction contributes to the proliferation of osteosarcomas. We report here that osteosarcoma-platelet interactions induce the release of platelet-derived growth factor (PDGF) from platelets, which promotes the pro...

  14. Standardization of a Protocol for Obtaining Platelet Rich Plasma from blood Donors; a Tool for Tissue Regeneration Procedures.

    Science.gov (United States)

    Gómez, Lina Andrea; Escobar, Magally; Peñuela, Oscar

    2015-01-01

    To develop a protocol for obtaining autologous platelet rich plasma in healthy individuals and to determine the concentration of five major growth factors before platelet activation. This protocol could be integrated into the guidelines of good clinical practice and research in regenerative medicine. Platelet rich plasma was isolated by centrifugation from 38 healthy men and 42 women ranging from 18 to 59 years old. The platelet count and quantification of growth factors were analyzed in eighty samples, stratified for age and gender of the donor. Analyses were performed using parametric the t-test or Pearson's analysis for non-parametric distribution. P platelet counts from 1.6 to 4.9 times (mean = 2.8). There was no correlation between platelet concentration and the level of the following growth factors: VEGF-D (r = 0.009, p = 0.4105), VEGF-A (r = 0.0068, p = 0.953), PDGF subunit AA (p = 0.3618; r = 0.1047), PDGF-BB (p = 0.5936; r = 0.6095). In the same way, there was no correlation between donor gender and growth factor concentrations. Only TGF-β concentration was correlated to platelet concentration (r = 0.3163, p = 0.0175). The procedure used allowed us to make preparations rich in platelets, low in leukocytes and red blood cells, and sterile. Our results showed biological variations in content of growth factors in PRP. The factors influencing these results should be further studied.

  15. Platelets alter gene expression profile in human brain endothelial cells in an in vitro model of cerebral malaria.

    Directory of Open Access Journals (Sweden)

    Mathieu Barbier

    Full Text Available Platelet adhesion to the brain microvasculature has been associated with cerebral malaria (CM in humans, suggesting that platelets play a role in the pathogenesis of this syndrome. In vitro co-cultures have shown that platelets can act as a bridge between Plasmodium falciparum-infected red blood cells (pRBC and human brain microvascular endothelial cells (HBEC and potentiate HBEC apoptosis. Using cDNA microarray technology, we analyzed transcriptional changes of HBEC in response to platelets in the presence or the absence of tumor necrosis factor (TNF and pRBC, which have been reported to alter gene expression in endothelial cells. Using a rigorous statistical approach with multiple test corrections, we showed a significant effect of platelets on gene expression in HBEC. We also detected a strong effect of TNF, whereas there was no transcriptional change induced specifically by pRBC. Nevertheless, a global ANOVA and a two-way ANOVA suggested that pRBC acted in interaction with platelets and TNF to alter gene expression in HBEC. The expression of selected genes was validated by RT-qPCR. The analysis of gene functional annotation indicated that platelets induce the expression of genes involved in inflammation and apoptosis, such as genes involved in chemokine-, TREM1-, cytokine-, IL10-, TGFβ-, death-receptor-, and apoptosis-signaling. Overall, our results support the hypothesis that platelets play a pathogenic role in CM.

  16. Responsiveness of platelets during storage studied with flow cytometry - formation of platelet subpopulations and LAMP-1 as new markers for the platelet storage lesion

    OpenAIRE

    Södergren, Anna; Tynngård, Nahreen; Berlin, Gösta; Ramström, Sofia

    2016-01-01

    Background and ObjectivesStorage lesions may prevent transfused platelets to respond to agonists and arrest bleeding. The aim of this study was to evaluate and quantify the capacity of platelet activation during storage using flow cytometry and new markers of platelet activation. Materials and MethodsActivation responses of platelets prepared by apheresis were measured on days 1, 5, 7 and 12. In addition, comparisons were made for platelet concentrates stored until swirling was affected. Lyso...

  17. The effect of storage on platelet morphology

    NARCIS (Netherlands)

    Sturk, A.; Burt, L. M.; Hakvoort, T.; ten Cate, J. W.; Crawford, N.

    1982-01-01

    Platelet concentrates were stored for one, two or three days at 4 degrees C (unagitated) or at room temperature (unagitated and linearly agitated). After washing the concentrates twice at room temperature and then incubating them for 60 minutes at 37 degrees C, the platelet morphology was

  18. Novel agents for anti-platelet therapy

    Directory of Open Access Journals (Sweden)

    Ji Xuebin

    2011-11-01

    Full Text Available Abstract Anti-platelet therapy plays an important role in the treatment of patients with thrombotic diseases. The most commonly used anti-platelet drugs, namely, aspirin, ticlopidine, and clopidogrel, are effective in the prevention and treatment of cardio-cerebrovascular diseases. Glycoprotein IIb/IIIa antagonists (e.g., abciximab, eptifibatide and tirofiban have demonstrated good clinical benefits and safety profiles in decreasing ischemic events in acute coronary syndrome. However, adverse events related to thrombosis or bleeding have been reported in cases of therapy with glycoprotein IIb/IIIa antagonists. Cilostazol is an anti-platelet agent used in the treatment of patients with peripheral ischemia, such as intermittent claudication. Presently, platelet adenosine diphosphate P2Y(12 receptor antagonists (e.g., clopidogrel, prasugrel, cangrelor, and ticagrelor are being used in clinical settings for their pronounced protective effects. The new protease-activated receptor antagonists, vorapaxar and atopaxar, potentially decrease the risk of ischemic events without significantly increasing the rate of bleeding. Some other new anti-platelet drugs undergoing clinical trials have also been introduced. Indeed, the number of new anti-platelet drugs is increasing. Consequently, the efficacy of these anti-platelet agents in actual patients warrants scrutiny, especially in terms of the hemorrhagic risks. Hopefully, new selective platelet inhibitors with high anti-thrombotic efficiencies and low hemorrhagic side effects can be developed.

  19. The life cycle of platelet granules.

    Science.gov (United States)

    Sharda, Anish; Flaumenhaft, Robert

    2018-01-01

    Platelet granules are unique among secretory vesicles in both their content and their life cycle. Platelets contain three major granule types-dense granules, α-granules, and lysosomes-although other granule types have been reported. Dense granules and α-granules are the most well-studied and the most physiologically important. Platelet granules are formed in large, multilobulated cells, termed megakaryocytes, prior to transport into platelets. The biogenesis of dense granules and α-granules involves common but also distinct pathways. Both are formed from the trans -Golgi network and early endosomes and mature in multivesicular bodies, but the formation of dense granules requires trafficking machinery different from that of α-granules. Following formation in the megakaryocyte body, both granule types are transported through and mature in long proplatelet extensions prior to the release of nascent platelets into the bloodstream. Granules remain stored in circulating platelets until platelet activation triggers the exocytosis of their contents. Soluble N -ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins, located on both the granules and target membranes, provide the mechanical energy that enables membrane fusion during both granulogenesis and exocytosis. The function of these core fusion engines is controlled by SNARE regulators, which direct the site, timing, and extent to which these SNAREs interact and consequently the resulting membrane fusion. In this review, we assess new developments in the study of platelet granules, from their generation to their exocytosis.

  20. The origin and function of platelet glycosyltransferases

    DEFF Research Database (Denmark)

    Wandall, Hans H; Rumjantseva, Viktoria; Sørensen, Anne Louise Tølbøll

    2012-01-01

    Platelets are megakaryocyte subfragments that participate in hemostatic and host defense reactions and deliver pro- and anti-angiogenic factors throughout the vascular system. Platelets are anucleated cells and lack a complex secretory apparatus with distinct Golgi/endoplasmic reticulum compartme...

  1. The interplay between platelets and coagulation

    NARCIS (Netherlands)

    Weeterings, C.

    2009-01-01

    Platelet activation and blood coagulation are two processes often studied separately, but which cannot be seen independently from each other. Platelets play a pivotal role in coagulation, not only by providing negatively charged phospholipids, but also in localizing the coagulation process from a

  2. 21 CFR 864.6675 - Platelet aggregometer.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Platelet aggregometer. 864.6675 Section 864.6675 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Manual Hematology Devices § 864.6675 Platelet...

  3. Platelet transfusion therapy: from 1973 to 2005.

    NARCIS (Netherlands)

    Brand, A.; Novotny, V.M.J.; Tomson, B.

    2006-01-01

    Platelet transfusions are indispensable for supportive care of patients with hematological diseases. We describe the developments in platelet products for transfusion since the 1970s, when, in particular, support for patients with allo-antibodies against human leukocyte antigens was a laborious

  4. Platelet-Poor and Platelet-Rich Plasma Stimulate Bone Lineage Differentiation in Periodontal Ligament Stem Cells.

    Science.gov (United States)

    Martínez, Constanza E; González, Sergio A; Palma, Verónica; Smith, Patricio C

    2016-02-01

    Plasma-derived fractions have been used as an autologous source of growth factors; however, limited knowledge concerning their biologic effects has hampered their clinical application. In this study, the authors analyze the content and specific effect of both platelet-rich plasma (PRP) and platelet-poor plasma (PPP) on osteoblastic differentiation using primary cultures of human periodontal ligament stem cells (HPLSCs). The authors evaluated the growth factor content of PRP and PPP using a proteome profiler array and enzyme-linked immunosorbent assay. HPLSCs were characterized by flow cytometry and differentiation assays. The effect of PRP and PPP on HPLSC bone differentiation was analyzed by quantifying calcium deposition after 14 and 21 days of treatment. Albeit at different concentrations, the two fractions had similar profiles of growth factors, the most representative being platelet-derived growth factor (PDGF) isoforms (PDGF-AA, -BB, and -AB), insulin-like growth factor binding protein (IGFBP)-2, and IGFBP-6. Both formulations exerted a comparable stimulus on osteoblastic differentiation even at low doses (2.5%), increasing calcium deposits in HPLSCs. PRP and PPP showed a similar protein profile and exerted comparable effects on bone differentiation. Further studies are needed to characterize and compare the effects of PPP and PRP on bone healing in vivo.

  5. EXTENDED STORAGE OF BUFFY-COAT PLATELET CONCENTRATES IN PLASMA OR A PLATELET ADDITIVE SOLUTION

    Science.gov (United States)

    Slichter, Sherrill J.; Bolgiano, Doug; Corson, Jill; Jones, Mary Kay; Christoffel, Todd; Bailey, S. Lawrence; Pellham, Esther

    2014-01-01

    Background Platelet concentrates prepared from whole blood in the U.S. are made using the platelet-rich-plasma (PRP) method. The platelet concentrates must be made within 8 hours of blood collection and stored for only 5 days. In Europe and Canada, platelet concentrates are made using the buffy-coat (BC) method from whole blood held overnight at 22°C and storage times may be up to 7 days. Our studies were designed to determine how long BC platelets can be stored in plasma or Plasmalyte while meeting the FDA’s post-storage viability criteria. Study Design, Materials, And Methods Normal subjects donated whole blood that was stored at 22°C for 22 ± 2 hours prior to preparation of BC platelets. Platelets were stored for 5 to 8 days in either plasma or Plasmalyte concentrations of 65% or 80%. Radiolabeled autologous stored versus fresh platelet recoveries and survivals were assessed as well as post-storage in vitro assays. Results BC platelets stored in either plasma or 65% Plasmalyte met FDA post-storage platelet recovery criteria for 7 days but survivals for only 6 days, while storage in 80% Plasmalyte gave very poor results. Both stored platelet recoveries and survivals correlated with the same donor’s fresh results, but the correlation was much stronger between recoveries than survivals. In vitro measures of extent of shape change, morphology score, and pH best predicted post-storage platelet recoveries, while annexin V binding best predicted platelet survivals. Conclusion BC platelets stored in either plasma or 65% Plasmalyte meet FDA’s post-storage viability criteria for 6 days. PMID:24673482

  6. Influence of nitriding atmosphere on the modification of surface titanium with focus on the behavior of blood platelets adhesion

    International Nuclear Information System (INIS)

    Vitoriano, J.O.; Alves, C.; Braz, D.C.; Camara, R.B.G.; Rocha, H.A.O.

    2014-01-01

    The present study aimed to analyze the influence of surface modification of titanium on the adhesion of blood platelets, through techniques of adhesion and morphological analyzes. Discs of titanium grade II received different surface treatments with plasma of Ar + N_2 + H_2 and Ar + H_2, forming two experimental groups including only polished samples used as standard. Before and after treatment the samples were characterized according to topography, crystalline structure and wettability, using atomic force microscopy, X-ray diffraction, Raman spectroscopy and testing of sessile drop, respectively. Platelet rich plasma (PRP) was applied on the modified surfaces in a culture plates. Images obtained by electron microscopy of adhered platelets were analyzed to verify the behavior of platelets in the different experimental conditions. (author)

  7. Platelet mitochondrial function and dysfunction: physiological consequences

    International Nuclear Information System (INIS)

    Popov, D.

    2015-01-01

    There is a general trend in revisiting mitochondria using the up-to-date technologies that uncovered novel attributes of this organelle, such as the intracellular displacement to locations where an energy supply is needed, the dynamic shape changes and turnover, the initiation of signaling to the rest of the cell, and the ability to crosstalk with other cellular organelles. The in-depth scrutiny of platelet mitochondria role in health and pathology is included within this ongoing revisiting trend. The current article puts into a nutshell the most recent data on platelet mitochondria function and disease-related ion, focusing on generation of stress- and apoptosis-related signaling molecules, overproduction of reactive oxygen species during activation and disease, on the biomarker potential of platelets mitochondria, and their prospective exploitation in translational applications. These novel findings complete the physiological profile of platelets and could have potential therapeutic effectiveness in platelet-associated disorders.

  8. Does bipolar pacemaker current activate blood platelets?

    DEFF Research Database (Denmark)

    Gjesdal, Grunde; Hansen, Annebirthe Bo; Brandes, Axel

    2009-01-01

    OBJECTIVE: The aim of this study was to investigate whether bipolar pacemaker current lead can activate blood platelets. The null hypothesis was that 1 minute of electrical stimulation of platelets would not influence their subsequent reactivity to adenosine diphosphate (ADP). BACKGROUND: Both...... platelets and muscle cells contain actin and myosin filaments, and both cells are activated following calcium influx. Muscle cells open their calcium channels and contract when exposed to an electric current. Current through a bipolar pacemaker lead will expose a small volume of blood, including platelets......, to the depolarizing current. Platelet activation may ensue, resulting in aggregation, release reaction, and contraction. In contrast, a unipolar pacemaker system will not depolarize blood, but transmit current directly into the myocardium, and the current afterward passes through other tissues before returning...

  9. Of von Willebrand factor and platelets.

    Science.gov (United States)

    Bryckaert, Marijke; Rosa, Jean-Philippe; Denis, Cécile V; Lenting, Peter J

    2015-01-01

    Hemostasis and pathological thrombus formation are dynamic processes that require multiple adhesive receptor-ligand interactions, with blood platelets at the heart of such events. Many studies have contributed to shed light on the importance of von Willebrand factor (VWF) interaction with its platelet receptors, glycoprotein (GP) Ib-IX-V and αIIbβ3 integrin, in promoting primary platelet adhesion and aggregation following vessel injury. This review will recapitulate our current knowledge on the subject from the rheological aspect to the spatio-temporal development of thrombus formation. We will also discuss the signaling events generated by VWF/GPIb-IX-V interaction, leading to platelet activation. Additionally, we will review the growing body of evidence gathered from the recent development of pathological mouse models suggesting that VWF binding to GPIb-IX-V is a promising target in arterial and venous pathological thrombosis. Finally, the pathological aspects of VWF and its impact on platelets will be addressed.

  10. Platelet mitochondrial function and dysfunction: physiological consequences

    Energy Technology Data Exchange (ETDEWEB)

    Popov, D.

    2015-07-01

    There is a general trend in revisiting mitochondria using the up-to-date technologies that uncovered novel attributes of this organelle, such as the intracellular displacement to locations where an energy supply is needed, the dynamic shape changes and turnover, the initiation of signaling to the rest of the cell, and the ability to crosstalk with other cellular organelles. The in-depth scrutiny of platelet mitochondria role in health and pathology is included within this ongoing revisiting trend. The current article puts into a nutshell the most recent data on platelet mitochondria function and disease-related ion, focusing on generation of stress- and apoptosis-related signaling molecules, overproduction of reactive oxygen species during activation and disease, on the biomarker potential of platelets mitochondria, and their prospective exploitation in translational applications. These novel findings complete the physiological profile of platelets and could have potential therapeutic effectiveness in platelet-associated disorders.

  11. Platelet-rich plasma in otolaryngology.

    Science.gov (United States)

    Stavrakas, M; Karkos, P D; Markou, K; Grigoriadis, N

    2016-12-01

    Platelet-rich plasma is a novel material that is being used more frequently in many surgical specialties. A literature review on the current and potential uses of platelet-rich plasma in otolaryngology was performed. There is limited evidence on the use of platelet-rich plasma in otolaryngology compared with other specialties: only 11 studies on various subspecialties (otology, rhinology and laryngology) were included in the final review. Based on the limited number of studies, we cannot draw safe conclusions about the value of platelet-rich plasma in otolaryngology. Nevertheless, the available literature suggests that platelet-rich plasma holds promise for future research and may have a number of clinical applications.

  12. Evaluation of three methods of platelet labelling

    International Nuclear Information System (INIS)

    Mortelmans, L.; Verbruggen, A.; Roo, M. de; Vermylen, J.

    1986-01-01

    The study of the kinetics of labelled platelets makes sense only when the platelets preserve their viability after separation and labelling. The separation and labelling procedures described in the manual of two producers of 111 In-oxinate (Amersham, Mallinckrodt) have been evaluated by in vitro aggregation tests. The method of Mallinckrodt diminished the aggregation capacities of the thrombocytes. The labelled platelets with normal in vitro aggregation response (Amersham) were tested in vivo in 11 patients who underwent peripheral bypass surgery. The platelet half-life and the platelet accumulation on bypass grafts were checked one week post-operatively. Because of the poor in vivo response of both methods (exponential half-life curve and bad graft visualization), a third method based on that described by W.A. Heaton et al. 1979 was optimized in the authors' laboratory with good in vitro and in vivo results in 12 patients. (author)

  13. Evaluation of three methods of platelet labelling.

    Science.gov (United States)

    Mortelmans, L; Verbruggen, A; De Roo, M; Vermylen, J

    1986-07-01

    The study of the kinetics of labelled platelets makes sense only when the platelets preserve their viability after separation and labelling. The separation and labelling procedures described in the manual of two producers of 111In-oxinate (Amersham, Mallinckrodt) have been evaluated by in vitro aggregation tests. The method of Mallinckrodt diminished the aggregation capacities of the thrombocytes. The labelled platelets with normal in vitro aggregation response (Amersham) were tested in vivo in 11 patients who underwent peripheral bypass surgery. The platelet half-life and the platelet accumulation on bypass grafts were checked one week post-operatively. Because of the poor in vivo response of both methods (exponential half-life curve and bad graft visualization), a third method was optimized in our laboratory with good in vitro and in vivo results in 12 patients.

  14. Dietary flavanols and procyanidin oligomers from cocoa (Theobroma cacao) inhibit platelet function.

    Science.gov (United States)

    Murphy, Karen J; Chronopoulos, Andriana K; Singh, Indu; Francis, Maureen A; Moriarty, Helen; Pike, Marilyn J; Turner, Alan H; Mann, Neil J; Sinclair, Andrew J

    2003-06-01

    Flavonoids may be partly responsible for some health benefits, including antiinflammatory action and a decreased tendency for the blood to clot. An acute dose of flavanols and oligomeric procyanidins from cocoa powder inhibits platelet activation and function over 6 h in humans. This study sought to evaluate whether 28 d of supplementation with cocoa flavanols and related procyanidin oligomers would modulate human platelet reactivity and primary hemostasis and reduce oxidative markers in vivo. Thirty-two healthy subjects were assigned to consume active (234 mg cocoa flavanols and procyanidins/d) or placebo (cocoa flavanols and procyanidins/d) tablets in a blinded parallel-designed study. Platelet function was determined by measuring platelet aggregation, ATP release, and expression of activation-dependent platelet antigens by using flow cytometry. Plasma was analyzed for oxidation markers and antioxidant status. Plasma concentrations of epicatechin and catechin in the active group increased by 81% and 28%, respectively, during the intervention period. The active group had significantly lower P selectin expression and significantly lower ADP-induced aggregation and collagen-induced aggregation than did the placebo group. Plasma ascorbic acid concentrations were significantly higher in the active than in the placebo group (P antioxidant status did not change in either group. Cocoa flavanol and procyanidin supplementation for 28 d significantly increased plasma epicatechin and catechin concentrations and significantly decreased platelet function. These data support the results of acute studies that used higher doses of cocoa flavanols and procyanidins.

  15. Description of a double centrifugation tube method for concentrating canine platelets.

    Science.gov (United States)

    Perazzi, Anna; Busetto, Roberto; Martinello, Tiziana; Drigo, Michele; Pasotto, Daniela; Cian, Francesco; Patruno, Marco; Iacopetti, Ilaria

    2013-07-22

    To evaluate the efficiency of platelet-rich plasma preparations by means of a double centrifugation tube method to obtain platelet-rich canine plasma at a concentration at least 4 times higher than the baseline value and a concentration of white blood cells not exceeding twice the reference range. A complete blood count was carried out for each sample and each concentrate. Whole blood samples were collected from 12 clinically healthy dogs (consenting blood donors). Blood was processed by a double centrifugation tube method to obtain platelet concentrates, which were then analyzed by a flow cytometry haematology system for haemogram. Platelet concentration and white blood cell count were determined in all samples. Platelet concentration at least 4 times higher than the baseline value and a white blood cell count not exceeding twice the reference range were obtained respectively in 10 cases out of 12 (83.3%) and 11 cases out of 12 (91.6%). This double centrifugation tube method is a relatively simple and inexpensive method for obtaining platelet-rich canine plasma, potentially available for therapeutic use to improve the healing process.

  16. Nattokinase improves blood flow by inhibiting platelet aggregation and thrombus formation.

    Science.gov (United States)

    Jang, Ja-Young; Kim, Tae-Su; Cai, Jingmei; Kim, Jihyun; Kim, Youngeun; Shin, Kyungha; Kim, Kwang Sei; Park, Sung Kyeong; Lee, Sung-Pyo; Choi, Ehn-Kyoung; Rhee, Man Hee; Kim, Yun-Bae

    2013-12-01

    The effects of nattokinase on the in vitro platelet aggregation and in vivo thrombosis were investigated in comparison with aspirin. Rabbit platelet-rich plasma was incubated with nattokinase and aggregation inducers collagen and thrombin, and the platelet aggregation rate was analyzed. Nattokinase significantly inhibited both the collagen- and thrombin-induced platelet aggregations. Nattokinase also reduced thromboxane B2 formation from collagen-activated platelets in a concentration-dependent manner. Rats were orally administered with nattokinase for 1 week, and their carotid arteries were exposed. Arterial thrombosis was induced by applying 35% FeCl3-soaked filter paper for 10 min, and the blood flow was monitored with a laser Doppler probe. Nattokinase delayed the FeCl3-induced arterial occlusion in a dose-dependent manner, doubling the occlusion time at 160 mg/kg. In addition, a high dose (500 mg/kg) of nattokinase fully prevented the occlusion, as achieved with aspirin (30 mg/kg). The results indicate that nattokinase extracted from fermented soybean inhibit platelet aggregation by blocking thromboxane formation, and thereby delay thrombosis following oxidative arterial wall injury. Therefore, it is suggested that nattokinase could be a good candidate without adverse effects for the improvement of blood flow.

  17. Deposition of fibrinogen on the surface of in vitro thrombi prevents platelet adhesion.

    Science.gov (United States)

    Owaynat, Hadil; Yermolenko, Ivan S; Turaga, Ramya; Lishko, Valeryi K; Sheller, Michael R; Ugarova, Tatiana P

    2015-12-01

    The initial accumulation of platelets after vessel injury is followed by thrombin-mediated generation of fibrin which is deposited around the plug. While numerous in vitro studies have shown that fibrin is highly adhesive for platelets, the surface of experimental thrombi in vivo contains very few platelets suggesting the existence of natural anti-adhesive mechanisms protecting stabilized thrombi from platelet accumulation and continuous thrombus propagation. We previously showed that adsorption of fibrinogen on pure fibrin clots results in the formation of a nonadhesive matrix, highlighting a possible role of this process in surface-mediated control of thrombus growth. However, the deposition of fibrinogen on the surface of blood clots has not been examined. In this study, we investigated the presence of intact fibrinogen on the surface of fibrin-rich thrombi generated from flowing blood and determined whether deposited fibrinogen is nonadhesive for platelets. Stabilized fibrin-rich thrombi were generated using a flow chamber and the time that platelets spend on the surface of thrombi was determined by video recording. The presence of fibrinogen and fibrin on the surface of thrombi was analyzed by confocal microscopy using specific antibodies. Examination of the spatial distribution of two proteins revealed the presence of intact fibrinogen on the surface of stabilized thrombi. By manipulating the surface of thrombi to display either fibrin or intact fibrinogen, we found that platelets adhere to fibrin- but not to fibrinogen-coated thrombi. These results indicate that the fibrinogen matrix assembled on the outer layer of stabilized in vitro thrombi protects them from platelet adhesion. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. Clot formation and lysis in platelet rich plasma of healthy donors and patients with resistant hypertension

    Directory of Open Access Journals (Sweden)

    I. I. Patalakh

    2018-04-01

    Full Text Available Hemostatic balance in blood is affected by numerous factors, including coagulation and fibrinolytic proteins, the wide spectrum of their inhibitors, and blood cells. Since platelets can participate in contradictory processes, they significantly complicate the whole picture. Therefore, nowadays the development of global assays of hemostasis, which can reflect the physiological process of hemostasis and can be used for point-of-care diagnosis of thrombosis, is crucial. This paper outlines a new approach we used to analyze the capabilities of clot waveform analysis tools to distinguish the response of platelet-rich plasma from healthy donors and patients with arterial hypertension caused by stimulation of coagulation and lysis (with exogenous thrombin and recombinant tissue-type plasminogen activator, respectively. In donor plasma, when the clot degradation was accompanied by 40 IU/ml of recombinant tissue-type plasminogen activator, platelets potentiated fibrinolysis more than coagulation, which ultimately shifts the overall balance to a profibrinolytic state. At the same time, for patients with hypertension, platelets, embedded in clot obtained from platelet-rich plasma, showed a weaker ability to stimulate fibrinolysis. The obtained data gives the evidence that platelets can act not only as procoagulants but also as profibrinolytics. By simultaneously amplifying coagulation and fibrinolysis, making their rates comparable, platelets would control plasma procoagulant activity, thereby regulating local hemostatic balance, the size and lifetime of the clot. Moreover, clot waveform analysis may be used to distinguish the effects of platelet-rich plasma on clotting or lysis of fibrin clots in healthy donors and patients with essential hypertension.

  19. [Platelet function in acute myeloid leukemia. II. Aggregation of isolated platelets].

    Science.gov (United States)

    Zawilska, K; Komarnicki, M; Mańka, B

    1978-01-01

    In 22 patients with acute myeloid leukaemia (17 cases of myeloblastic leukaemia, 4 cases of myelomonocytic leukaemia and 1 case of undifferentiated-cell leukaemia) platelets were isolated from the plasma by the method of Nicholls and Hampton as modified by Levy-Toledano by centrifugation in albumin gradient. The aim of platelet isolation was their "concentration" in cases of thrombocytopenia to values making possible aggregation tests, and platelet separation from the influence of plasma factors. Then aggregation of isolated platelets caused by ADP was studied. In 16 out of 22 patients a fall of aggregation was observed, with the mean values of aggregation rate and intensity were significantly lower. Parallelly done determinations of aggregating activity released from the platelets by thrombin showed lower values as compared with platelets from healthy subjects. In might be thought, in this connection, that the demonstrated reduction of isolated platelets is associated with a diminution of the nucleotide pool or disturbances of the platelet release reaction. The disturbances of the platelet release reaction. The disturbances of aggregation of isolated platelets and reduction of the aggregating activity were most pronounced in acute myelomonocytic leukaemia.

  20. Freezing of Apheresis Platelet Concentrates in 6% Dimethyl Sulfoxide: The First Preliminary Study in Turkey

    Directory of Open Access Journals (Sweden)

    Soner Yılmaz

    2016-03-01

    Full Text Available Objective: Transfusion of platelet suspensions is an essential part of patient care for certain clinical indications. In this pioneering study in Turkey, we aimed to assess the in vitro hemostatic functions of platelets after cryopreservation. Materials and Methods: Seven units of platelet concentrates were obtained by apheresis. Each apheresis platelet concentrate (APC was divided into 2 equal volumes and frozen with 6% dimethyl sulfoxide (DMSO. The 14 frozen units of APCs were kept at -80 °C for 1 day. APCs were thawed at 37 °C and diluted either with autologous plasma or 0.9% NaCl. The volume and residual numbers of leukocytes and platelets were tested in both before-freezing and post-thawing periods. Aggregation and thrombin generation tests were used to analyze the in vitro hemostatic functions of platelets. Flow-cytometric analysis was used to assess the presence of frozen treated platelets and their viability. Results: The residual number of leukocytes in both dilution groups was <1x106. The mean platelet recovery rate in the plasma-diluted group (88.1±9.5% was higher than that in the 0.9% NaCl-diluted group (63±10%. These results were compatible with the European Directorate for the Quality of Medicines quality criteria. Expectedly, there was no aggregation response to platelet aggregation test. The mean thrombin generation potential of postthaw APCs was higher in the plasma-diluted group (2411 nmol/L per minute when compared to both the 0.9% NaCl-diluted group (1913 nmol/L per minute and the before-freezing period (1681 nmol/L per minute. The flowcytometric analysis results for the viability of APCs after cryopreservation were 94.9% and 96.6% in the plasma and 0.9% NaCl groups, respectively. Conclusion: Cryopreservation of platelets with 6% DMSO and storage at -80 °C increases their shelf life from 7 days to 2 years. Besides the increase in hemostatic functions of platelets, the cryopreservation process also does not affect their

  1. Platelet binding and biodistribution of [99mTc]rBitistatin in animal species and humans

    International Nuclear Information System (INIS)

    Knight, Linda C.; Romano, Jan E.; Bright, Lewis T.; Agelan, Alexis; Kantor, Steven; Maurer, Alan H.

    2007-01-01

    Introduction: 99m Tc recombinant bitistatin (rBitistatin) is a radioligand for α IIb β 3 (glycoproteins IIb/IIIa) receptor on platelets and is being developed as a diagnostic radiopharmaceutical for in vivo imaging of acute thrombi and emboli. Prior to the first administration of [ 99m Tc]rBitistatin to human subjects, its biodistribution and effects on platelets were evaluated in animals. This paper reports findings in animal studies in comparison with initial findings in normal human subjects. Methods: [ 99m Tc]rBitistatin was administered to mice, guinea pigs and dogs to assess time-dependent organ distribution, urinary excretion and blood disappearance rates. Blood samples were analyzed to determine radioligand binding to circulating platelets and the extent of plasma protein binding. The effect of [ 99m Tc]rBitistatin on circulating platelet count was determined. These factors were also determined in normal human subjects who received [ 99m Tc]rBitistatin as part of a Phase I clinical trial. Results: The main organs that accumulated [ 99m Tc]rBitistatin were kidneys, liver and spleen in all animal species and humans. The main organs seen on human images were the kidneys and spleen. Liver uptake was fainter, and soft-tissue background was low. [ 99m Tc]rBitistatin bound to circulating platelets in blood, with a higher percentage of binding to platelets in guinea pigs and dogs compared to that in humans. Plasma protein binding was low and of little consequence in view of platelet binding. The main route of excretion was through the urine. [ 99m Tc]rBitistatin did not affect platelet counts in humans or dogs. Conclusions: [ 99m Tc]rBitistatin, when administered at low doses for imaging, has no adverse effects on platelets and has the qualitative biodistribution predicted by animal studies. [ 99m Tc]rBitistatin was found to bind to circulating platelets in humans, suggesting that it will be able to bind to activated platelets in vivo in patients with acute

  2. Breaking the mold: transcription factors in the anucleate platelet and platelet-derived microparticles

    Directory of Open Access Journals (Sweden)

    Katie L Lannan

    2015-02-01

    Full Text Available Platelets are small anucleate blood cells derived from megakaryocytes. In addition to their pivotal roles in hemostasis, platelets are the smallest, yet most abundant, immune cell and regulate inflammation, immunity, and disease progression. Although platelets lack DNA, and thus no functional transcriptional activities, they are nonetheless rich sources of RNAs, possess an intact spliceosome, and are thus capable of synthesizing proteins. Previously, it was thought that platelet RNAs and translational machinery were remnants from the megakaryocyte. We now know that the initial description of platelets as cellular fragments is an antiquated notion, as mounting evidence suggests otherwise. Therefore, it is reasonable to hypothesize that platelet transcription factors are not vestigial remnants from megakaryoctes, but have important, if only partly understood functions. Proteins play multiple cellular roles to minimize energy expenditure for maximum cellular function; thus, the same can be expected for transcription factors. In fact, numerous transcription factors have non-genomic roles, both in platelets and in nucleated cells. Our lab and others have discovered the presence and nongenomic roles of transcription factors in platelets, such as the nuclear factor kappa β (NFκB family of proteins and peroxisome proliferator activated receptor gamma (PPARγ. In addition to numerous roles in regulating platelet activation, functional transcription factors can be transferred to vascular and immune cells through platelet microparticles. This method of transcellular delivery of key immune molecules may be a vital mechanism by which platelet transcription factors regulate inflammation and immunity. At the very least, platelets are an ideal model cell to dissect out the nongenomic roles of transcription factors in nucleated cells. There is abundant evidence to suggest that transcription factors in platelets play key roles in regulating inflammatory and

  3. Platelet lysates produced from expired platelet concentrates support growth and osteogenic differentiation of mesenchymal stem cells.

    Directory of Open Access Journals (Sweden)

    Sandra Mjoll Jonsdottir-Buch

    Full Text Available BACKGROUND: Mesenchymal stem cells are promising candidates in regenerative cell therapy. Conventional culture methods involve the use of animal substances, specifically fetal bovine serum as growth supplement. Since the use of animal-derived products is undesirable for human applications, platelet lysates produced from human platelets are an attractive alternative. This is especially true if platelet lysates from already approved transfusion units at blood banks can be utilized. The purpose of this study was to produce human platelet lysates from expired, blood bank-approved platelet concentrates and evaluate their use as growth supplement in the culture of mesenchymal stem cells. METHODOLOGY/PRINCIPAL FINDINGS: In this study, bone marrow-derived mesenchymal stem cells were cultured with one of three culture supplements; fetal bovine serum, lysates from freshly prepared human platelet concentrates, or lysates from expired human platelet concentrates. The effects of these platelet-derived culture supplements on basic mesenchymal stem cell characteristics were evaluated. All cultures maintained the typical mesenchymal stem cell surface marker expression, trilineage differentiation potential, and the ability to suppress in vitro immune responses. However, mesenchymal stem cells supplemented with platelet lysates proliferated faster than traditionally cultured cells and increased the expression of the osteogenic marker gene RUNX-2; yet no difference between the use of fresh and expired platelet concentrates was observed. CONCLUSION/SIGNIFICANCE: Our findings suggest that human platelet lysates produced from expired platelet concentrates can be used as an alternative to fetal bovine serum for mesenchymal stem cell culture to the same extent as lysates from fresh platelets.

  4. Platelets

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  5. Blood platelets in the progression of Alzheimer's disease.

    Directory of Open Access Journals (Sweden)

    Nina S Gowert

    Full Text Available Alzheimer's disease (AD is characterized by neurotoxic amyloid-ß plaque formation in brain parenchyma and cerebral blood vessels known as cerebral amyloid angiopathy (CAA. Besides CAA, AD is strongly related to vascular diseases such as stroke and atherosclerosis. Cerebrovascular dysfunction occurs in AD patients leading to alterations in blood flow that might play an important role in AD pathology with neuronal loss and memory deficits. Platelets are the major players in hemostasis and thrombosis, but are also involved in neuroinflammatory diseases like AD. For many years, platelets were accepted as peripheral model to study the pathophysiology of AD because platelets display the enzymatic activities to generate amyloid-ß (Aß peptides. In addition, platelets are considered to be a biomarker for early diagnosis of AD. Effects of Aß peptides on platelets and the impact of platelets in the progression of AD remained, however, ill-defined. The present study explored the cellular mechanisms triggered by Aß in platelets. Treatment of platelets with Aß led to platelet activation and enhanced generation of reactive oxygen species (ROS and membrane scrambling, suggesting enhanced platelet apoptosis. More important, platelets modulate soluble Aß into fibrillar structures that were absorbed by apoptotic but not vital platelets. This together with enhanced platelet adhesion under flow ex vivo and in vivo and platelet accumulation at amyloid deposits of cerebral vessels of AD transgenic mice suggested that platelets are major contributors of CAA inducing platelet thrombus formation at vascular amyloid plaques leading to vessel occlusion critical for cerebrovascular events like stroke.

  6. Depressed reticuloendothelial clearance of platelets in rats after trauma.

    Science.gov (United States)

    Kaplan, J E; Moon, D G; Minnear, F L; Saba, T M

    1984-02-01

    Platelet microembolization may contribute to microcirculatory and organ damage following trauma and shock. It is hypothesized that posttraumatic reticuloendothelial depression predisposes to such microembolization by failure to clear altered platelets from the circulation. The present study evaluated the short-term (1 h) clearance and organ localization of radiolabeled homologous damaged platelets in normal rats and in rats following sublethal Noble-Collip drum trauma. Platelets were collected in citrated platelet-rich plasma from normal rats and labeled with 51Cr in citrated saline. Platelets were altered by repeated centrifugation in protein-free medium. These platelets differed functionally and morphologically from normal platelets. Disappearance of iv injected damaged platelets conformed to a two-compartment exponential clearance. Velocity of clearance in the rapid compartment correlated with hepatic platelet localization, whereas velocity of clearance in the second compartment correlated with splenic platelet localization. Clearance rate of the rapid compartment was depressed at 1 h after trauma and elevated at 24 h. These changes were associated with a decrease in hepatic platelet localization at 1 h and an increase above normal at 24 h. Splenic platelet localization was decreased by 3 h following trauma. Pulmonary platelet localization was increased at all times following trauma. It is concluded that the posttrauma state is associated with a defect in the reticuloendothelial system clearance of altered platelets, which may augment embolization of platelets in the lung.

  7. Platelet RNA as a circulating biomarker trove for cancer diagnostics.

    Science.gov (United States)

    Best, M G; Vancura, A; Wurdinger, T

    2017-07-01

    Platelets are multifunctional cell fragments, circulating in blood in high abundance. Platelets assist in thrombus formation, sensing of pathogens entering the blood stream, signaling to immune cells, releasing vascular remodeling factors, and, negatively, enhancing cancer metastasis. Platelets are 'educated' by their environment, including in patients with cancer. Cancer cells appear to initiate intraplatelet signaling, resulting in splicing of platelet pre-mRNAs, and enhance secretion of cytokines. Platelets can induce leukocyte and endothelial cell modeling factors, for example, through adenine nucleotides (ATP), thereby facilitating extravasation of cancer cells. Besides releasing factors, platelets can also sequester RNAs and proteins released by cancer cells. Thus, platelets actively respond to queues from local and systemic conditions, thereby altering their transcriptome and molecular content. Platelets contain a rich repertoire of RNA species, including mRNAs, small non-coding RNAs and circular RNAs; although studies regarding the functionality of the various platelet RNA species require more attention. Recent advances in high-throughput characterization of platelet mRNAs revealed 10 to > 1000 altered mRNAs in platelets in the presence of disease. Hence, platelet RNA appears to be dynamically affected by pathological conditions, thus possibly providing opportunities to use platelet RNA as diagnostic, prognostic, predictive, or monitoring biomarkers. In this review, we cover the literature regarding the platelet RNA families, processing of platelet RNAs, and the potential application of platelet RNA as disease biomarkers. © 2017 International Society on Thrombosis and Haemostasis.

  8. Brief Report: Platelet-Poor Plasma Serotonin in Autism

    Science.gov (United States)

    Anderson, George M.; Hertzig, Margaret E.; McBride, P. A.

    2012-01-01

    Possible explanations for the well-replicated platelet hyperserotonemia of autism include an alteration in the platelet's handling of serotonin (5-hydroxyserotonin, 5-HT) or an increased exposure of the platelet to 5-HT. Measurement of platelet-poor plasma (PPP) levels of 5-HT appears to provide the best available index of in vivo exposure of the…

  9. Platelet thrombosis in cardiac-valve prostheses

    International Nuclear Information System (INIS)

    Dewanjee, M.K.

    1989-01-01

    The contribution of platelets and clotting factors in thrombosis on cardiovascular prostheses had been quantified with several tracers. Thrombus formation in vivo could be measured semiquantitatively in animal models and patients with indium-111, Technetium-99m labeled platelets, iodine-123, iodine-131 labeled fibrinogen, and In-111 and Tc-99m labeled antibody to the fibrinogen-receptor on the platelet- membrane, or fibrin. The early studies demonstrated that certain platelet-inhibitors, e.g. sulfinpyrazone, aspirin or aspirin- persantine increased platelet survival time with mechanical valves implanted in the baboon model and patients. Thrombus localization by imaging is possible for large thrombus on thrombogenic surface of prosthesis in the acute phase. The majority of thrombus was found in the sewing ring (Dacron) in the acute phase in both the mechanical and tissue valves. The amount of retained thrombus in both mechanical and tissue valves in our one-day study in the dog model was similar (< 1% if injected In-111 platelets = 5 billion platelets). As the fibrous ingrowth covered the sewing ring, the thrombus formation decreased significantly. Only a small amount of thrombus was found on the leaflets at one month in both the dog and calf models. 38 refs., 9 figs., 5 tabs

  10. Platelet thrombosis in cardiac-valve prostheses

    Energy Technology Data Exchange (ETDEWEB)

    Dewanjee, M.K.

    1989-01-01

    The contribution of platelets and clotting factors in thrombosis on cardiovascular prostheses had been quantified with several tracers. Thrombus formation in vivo could be measured semiquantitatively in animal models and patients with indium-111, Technetium-99m labeled platelets, iodine-123, iodine-131 labeled fibrinogen, and In-111 and Tc-99m labeled antibody to the fibrinogen-receptor on the platelet- membrane, or fibrin. The early studies demonstrated that certain platelet-inhibitors, e.g. sulfinpyrazone, aspirin or aspirin- persantine increased platelet survival time with mechanical valves implanted in the baboon model and patients. Thrombus localization by imaging is possible for large thrombus on thrombogenic surface of prosthesis in the acute phase. The majority of thrombus was found in the sewing ring (Dacron) in the acute phase in both the mechanical and tissue valves. The amount of retained thrombus in both mechanical and tissue valves in our one-day study in the dog model was similar (< 1% if injected In-111 platelets = 5 billion platelets). As the fibrous ingrowth covered the sewing ring, the thrombus formation decreased significantly. Only a small amount of thrombus was found on the leaflets at one month in both the dog and calf models. 38 refs., 9 figs., 5 tabs.

  11. Pharmacological modulation of human platelet leukotriene C4-synthase.

    Science.gov (United States)

    Sala, A; Folco, G; Henson, P M; Murphy, R C

    1997-03-21

    The aim of this study was to test if human platelet leukotriene C4-synthase (LTC4-S) is pharmacologically different from cloned and expressed LTC4-S and, in light of the significant homologies between 5-lipoxygenase activating protein (FLAP) and LTC4-S, if different potencies of leukotriene synthesis inhibitors acting through binding with FLAP (FLAP inhibitors) reflect in different potencies as LTC4-S inhibitors. Leukotriene C4 (LTC4) synthesis by washed human platelets supplemented with synthetic leukotriene A4 (LTA4) was studied in the absence and presence of two different, structurally unrelated FLAP inhibitors (MK-886 and BAY-X1005) as well as a direct 5-lipoxygenase inhibitor (zileuton). LTC4 production was analyzed by RP-HPLC coupled to diode array detection. We report that human platelet LTC4-S was inhibited by MK-886 and BAY-X1005 (IC50 of 4.7 microM and 91.2 microM, respectively), but not by zileuton (inactive up to 300 microM); all 3 compounds were able to inhibit 5-lipoxygenase metabolite biosynthesis in intact human polymorphonuclear leukocytes (IC50 of 0.044 microM, 0.85 microM, and 1.5 microM, respectively). Platelet LTC4-S does not appear pharmacologically different from expression cloned LTC4-S. LTC4-S inhibition by FLAP inhibitors is in agreement with the significant homology reported for expression-cloned LTC4-S with FLAP, Furthermore, functional homology of the binding sites for inhibitors on LTC4-S and FLAP is suggested by the conservation of the relative potencies of MK-886 and BAY-X1005 vs FLAP-dependent 5-lipoxygenase activity and LTC4-S inhibition: MK-886 was 19.3-fold more potent than BAY-X1005 as FLAP inhibitor and 19.6-fold more potent than BAY-X1005 as LTC4-S inhibitor.

  12. Identification of functional VEGF receptors on human platelets.

    Science.gov (United States)

    Selheim, Frode; Holmsen, Holm; Vassbotn, Flemming S

    2002-02-13

    Platelets secrete platelet-derived growth factor (PDGF) and vascular endothelial growth factor (VEGF) upon stimulation. We have demonstrated that platelets have functionally active PDGF alpha-receptors, a transmembrane tyrosine kinase involved in negative feedback regulation. Here we demonstrate the presence of the related VEGF receptors fms-like tyrosine kinase-1 and kinase-insert domain region on human platelets. VEGF itself did not cause platelet aggregation. However, addition of exogenous VEGF to SFRLLN or thrombin-stimulated platelets potentiated platelet aggregation. Moreover, thrombin-induced phosphoinositide 3-kinase and mitogen-activated protein kinase activity were enhanced in the presence of VEGF.

  13. Imipramine binding in subpopulations of normal human blood platelets

    International Nuclear Information System (INIS)

    Arora, R.C.; Meltzer, H.Y.

    1984-01-01

    Imipramine binding was studied in platelet membranes isolated with different proportions of heavy (young) and light (old) platelets. The B/sub max/, a measure of the number of binding sites, was greater in the heavier platelets than in the light platelets. However, the dissociation constant K/sub d/ (a reflection of the affinity of imipramine binding) was greater in the lighter platelets compared to the heavy platelets. These results indicate that differences in K/sub d/ and B/sub max/ in particular membrane preparation, could be due to the differences in the relative proportion of heavy and light platelets

  14. Covalent modification of platelet proteins by palmitate

    International Nuclear Information System (INIS)

    Muszbek, L.; Laposata, M.

    1989-01-01

    Covalent attachment of fatty acid to proteins plays an important role in association of certain proteins with hydrophobic membrane structures. In platelets, the structure of many membrane glycoproteins (GPs) has been examined in detail, but the question of fatty acid acylation of platelet proteins has not been addressed. In this study, we wished to determine (a) whether platelet proteins could be fatty acid acylated; and, if so, (b) whether these modified proteins were present in isolated platelet membranes and cytoskeletal fractions; and (c) if the pattern of fatty acid acylated proteins changed on stimulation of the platelets with the agonist thrombin. We observed that in platelets allowed to incorporate 3H-palmitate, a small percentage (1.37%) of radioactivity incorporated into the cells became covalently bound to protein. Selective cleavage of thioester, thioester plus O-ester, and amide-linked 3H-fatty acids from proteins, and their subsequent analysis by high-performance liquid chromatography (HPLC) indicated that the greatest part of 3H-fatty acid covalently bound to protein was thioester-linked 3H-palmitate. By sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and fluorography, at least ten major radiolabeled proteins were detected. Activation of platelets by thrombin greatly increased the quantity of 3H-palmitoylated proteins associated with the cytoskeleton. Nearly all radiolabeled proteins were recovered in the membrane fraction, indicating that these proteins are either integral or peripheral membrane proteins or proteins tightly associated to membrane constituents. Components of the GPIIb-IIIa complex were not palmitoylated. Thus, platelet proteins are significantly modified posttranslationally by 3H-palmitate, and incorporation of palmitoylated proteins into the cytoskeleton is a prominent component of the platelet response to thrombin stimulation

  15. Establishment and Characterization of a Novel Chinese Human Lung Adenocarcinoma Cell Line CPA-Yang2 in Immunodeficient Mice

    Directory of Open Access Journals (Sweden)

    Shunfang YANG

    2009-10-01

    Full Text Available Background and objective The recurrence, metastasis and multidrug resistance (MDR in lung cancer are the tough problems worldwide. This study was to establish a novel chinese lung adenocarcinoma cell line with high metastasis potential for exploring the mechanism of reccurrence, development and MDR in lung cancer. Methods The cell came from the abdominal dropsy of a fifty-six years old female patient with lung adenocarcinoma and the tumor markers CA125, CYFRA21-1, CEA, NSE were detected to be higher secretion by radioimmunoassay in the abdominal dropsy. Tumorigenicity of immunodeficient mice was confirmed in 8th passage. The cell growth curve was mapped. Analysis of chromosome karyotype was tested. The gene expression was measured by real-time quantitative PCR. Results The tumorigenesis rate started at 8th passage in 3/10 immunodeficient mice via subcutaneously and the fully tumorigenicity was at 11th passage as well as later passages. Under the microscope, the cell showed oval-shap and adherence. The chromosome karyotype analysis of the cells was sub-triploid. Approximately 1×106 and 1.5×106 cancerous cells were injected into left cardiac ventricle and tail vein of immunodeficient mice respectively. The results showed multiorgan metastasis in the mice after three-four weeks, including mandible, scapula, humerus, vertebral column, femur, rib and brain, liver, adrenal gland, pulmonary in the mice after inoculation. The bone metastasis rate was 100% in the tumor bearing mice by bone scintigraphy and pathology. Quantitative real-time PCR was used to examined and compared with SPC-A-1 lung adenocarcinoma, ESM1, VEGF-C, IL-6, IL-8, AR genes were overexpressed. The novel cell was named CPA-Yang2. Conclusion The characteristics of novel strain CPA-Yang2 is a highly metastasis cell line of Chinese lung adenocarcinoma. It has stable traits, highly metastasis ability and maybe is a MDR lung cancerous cell line. Of course, it’s a good experimental

  16. Decrease in platelet activating factor stimulated phosphoinositide turnover during storage of human platelets in plasma

    International Nuclear Information System (INIS)

    Carter, M.G.; Shukla, S.D.

    1987-01-01

    Human platelet concentrate from the American Red Cross Blood Center was stored at 24 degree C in a shaker and aliquots were taken out at time intervals aseptically. Platelet activating factor (PAF) stimulated turnover of phosphoinositide (PPI) was monitored by assaying 32 P incorporation into phosphoinositides using platelet rich plasma (PRP). Platelets in PRP were incubated with 1 x 10 -7 M PAF at 37 degree C with gentle shaking and after 5 min their lipids were extracted and analysed by TLC for 32 P-phosphoinositides. The percent stimulation of 32 P incorporation by PAF (over control) into PPI was approximately 250, 100, 60, 25 and 20 on days 1, 2, 3, 5 and 6, respectively. This indicated a dramatic decrease in PAF responsive turnover of platelet PPI during storage. These findings have important implications in relation to PAF receptor activity and viability of platelets at different periods of storage

  17. Oxidative alterations during human platelet storage

    OpenAIRE

    Göker, Bahar; Özsavcı, Derya; Şener, Azize; Aksoy, Halil; Bağışgil, Vedat; Yanıkkaya Demirel, Gülderen; Uras, Fikriye

    2014-01-01

    SUMMARY: During storage of platelet obtained by apheresis several changes occur. The aimof this study was to investigate the effect of storage on activation, apoptosis, protein pattern,lipid peroxidation, and the levels of nitric oxide (NO) and glutathione (GSH) of platelets. In thisstudy, platelets obtained from healty donors (n=7) by apheresis were kept in an agitator fornine days at 20-24°C. The samples were taken on the 1st, 3 rd, 5 th and 9 th days and plateletswere precipitated. Platele...

  18. Transcellular lipoxygenase metabolism between monocytes and platelets

    Energy Technology Data Exchange (ETDEWEB)

    Bigby, T.D.; Meslier, N. (Univ. of California, San Francisco (USA))

    1989-09-15

    We have examined the effects of co-culture and in vitro co-stimulation on lipoxygenase metabolism in monocytes and platelets. Monocytes were obtained from the peripheral blood of normal volunteers by discontinuous gradient centrifugation and adherence to tissue culture plastic. Platelets were obtained from the platelet-rich plasma of the same donor. When 10(9) platelets and 2.5 x 10(6) monocytes were co-stimulated with 1 microM A23187, these preparations released greater quantities of 12(S)-hydroxy-10-trans-5,8,14-cis-eicosatetraenoic acid, 5(S),12-(S)dihydroxy-6,10-trans-8,14-cis-eicosatetraenoic acid, and leukotriene C4, 5(S)-hydroxy-6(R)-S-glutathionyl-7,9-trans-11,14-cis-eicosatetraenoic (LTC4) when compared with monocytes alone. Release of arachidonic acid, 5-HETE, delta 6-trans-LTB4, and delta 6-trans-12-epi-LTB4 from monocytes was decreased in the presence of platelets. A dose-response curve was constructed and revealed that the above changes became evident when the platelet number exceeded 10(7). Dual radiolabeling experiments with 3H- and 14C-arachidonic acid revealed that monocytes provided arachidonic acid, 5-HETE, and LTA4 for further metabolism by the platelet. Monocytes did not metabolize platelet intermediates detectably. In addition, as much as 1.2 microM 12(S)-hydroxy-10-trans-5,8,14-cis-eicosatetraenoic acid and 12(S)-hydroperoxy-10-trans-5,8,14-cis-eicosatetraenoic acid had no effect on monocyte lipoxygenase metabolism. Platelets were capable of converting LTA4 to LTC4, but conversion of LTA4 to LTB4 was not detected. We conclude that the monocyte and platelet lipoxygenase pathways undergo a transcellular lipoxygenase interaction that differs from the interaction of the neutrophil and platelet lipoxygenase pathways. In this interaction monocytes provide intermediate substrates for further metabolic conversion by platelets in an unidirectional manner.

  19. Flow cytometric assessment of activation of peripheral blood platelets in dogs with normal platelet count and asymptomatic thrombocytopenia.

    Science.gov (United States)

    Żmigrodzka, M; Guzera, M; Winnicka, A

    2016-01-01

    Platelets play a crucial role in hemostasis. Their activation has not yet been evaluated in healthy dogs with a normal and low platelet count. The aim of this study was to determine the influence of activators on platelet activation in dogs with a normal platelet count and asymptomatic thrombocytopenia. 72 clinically healthy dogs were enrolled. Patients were allocated into three groups. Group 1 consisted of 30 dogs with a normal platelet count, group 2 included 22 dogs with a platelet count between 100 and 200×109/l and group 3 consisted of 20 dogs with a platelet count lower than 100×109/l. Platelet rich-plasma (PRP) was obtained from peripheral blood samples using tripotassium ethylenediaminetetraacetic acid (K3-EDTA) as anticoagulant. Next, platelets were stimulated using phorbol-12-myristate-13-acetate or thrombin, stabilized using procaine or left unstimulated. The expression of CD51 and CD41/CD61 was evaluated. Co-expression of CD41/CD61 and Annexin V served as a marker of platelet activation. The expression of CD41/CD61 and CD51 did not differ between the 3 groups. Thrombin-stimulated platelets had a significantly higher activity in dogs with a normal platelet count than in dogs with asymptomatic thrombocytopenia. Procaine inhibited platelet activity in all groups. In conclusion, activation of platelets of healthy dogs in vitro varied depending on the platelet count and platelet activator.

  20. UV-C irradiation disrupts platelet surface disulfide bonds and activates the platelet integrin alphaIIbbeta3

    NARCIS (Netherlands)

    Verhaar, Robin; Dekkers, David W. C.; de Cuyper, Iris M.; Ginsberg, Mark H.; de Korte, Dirk; Verhoeven, Arthur J.

    2008-01-01

    UV-C irradiation has been shown to be effective for pathogen reduction in platelet concentrates, but preliminary work indicated that UV-C irradiation of platelets can induce platelet aggregation. In this study, the mechanism underlying this phenomenon was investigated. Irradiation of platelets with

  1. Diagnostic Accuracy of Platelet Count and Platelet Indices in Noninvasive Assessment of Fibrosis in Nonalcoholic Fatty Liver Disease Patients

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    Tamara Milovanovic Alempijevic

    2017-01-01

    Full Text Available Objective. Keeping in mind the rising prevalence of nonalcoholic fatty liver disease (NAFLD and the need to establish noninvasive tests for its detection, the aim of our study was to investigate whether platelet count (PC, mean platelet volume (MPV, and platelet distribution width (PDW can predict the presence of liver fibrosis in this group of patients. Methods. In 98 patients with NAFLD and 60 healthy volunteers, complete blood counts with automated differential counts were performed and values of PC, PDW, MPV, and PCT were analyzed. Results. Patients with NAFLD had lower PC and higher MPV, PCT, and PDW compared to the controls (P < 0.05. When NAFLD group was stratified according to severity of liver fibrosis, there was a statistically significant difference in the average values of PDW and PC between the groups (P < 0.05. Conclusion. Patients with NAFLD have significantly higher values of PCT, PDW, and MPV when compared to the healthy controls. Further studies are needed to establish their potential use for prediction of the degree of liver steatosis and fibrosis in NAFLD patients.

  2. Platelet-rich fibrin matrix for facial plastic surgery.

    Science.gov (United States)

    Sclafani, Anthony P; Saman, Masoud

    2012-05-01

    Platelets are known primarily for their role in hemostasis, but there is increasing interest in the effect of platelets on wound healing. Platelet isolates such as platelet-rich plasma have been advocated to enhance and accelerate wound healing. This article describes the use of a novel preparation, platelet-rich fibrin matrix (PRFM), for facial plastic surgery applications such as volume augmentation, fat transfer supplementation, and as an adjunct to open surgical procedures. Copyright © 2012 Elsevier Inc. All rights reserved.

  3. Mean Platelet Volume as an Indicator of Platelet Rejuvenation Following Bone Marrow Transplantation.

    Science.gov (United States)

    1986-07-01

    diameter N I Estes, 1968 Mucopolysaccharidosis diameter N I Estes, 1968 Osteogenesis imperfecta diameter N N Estes, 1968 Montreal Platelet Syndrome...6. Inherited Disorders of Connective Tissue: Platelet size was evaluated in 31 families with the following disorders: Osteogenesis imperfecta ...controlled by factors regulating the passage of platelets in and out of the pool. The splenic pool is known to be mobilized following exercise or epinephrine

  4. Experience of buffy coat pooling of platelets as a supportive care in thrombocytopenic dengue patients: A prospective study

    Directory of Open Access Journals (Sweden)

    Kabita Chatterjee

    2014-01-01

    Full Text Available Random donor platelet (RDP is not sufficient to improve the platelet count in most thrombocytopenic patients. Single donor platelet (SDP or buffy coat pooled platelet (BCPP are the two choices to provide a full therapeutic dose of platelets. However, there are constraints in the preparation of SDP due to stringent donor selection procedure, time required for procedure, and need of special expensive equipments and kits. BCPP is widely practiced, especially in the European countries, since 1995. In India, we decided to adopt the procedure of buffy coat pooling of platelets, especially for economically backward patients and for emergencies. This study was prospectively conducted from September 2009 to September 2010. A total of 129 units of BCPP [tested prior for viral markers by enzyme-linked immunosorbent assay (ELISA and individual donor nucleic acid amplification test (ID-NAT] were issued to 129 patients suffering from dengue and were included in this study. For comparison between efficacy of SDP and BCCP, patients were divided into two groups of 50 each. The post-transfusion platelet counts of the patients were noted after 2 hours of transfusion for each type of component. The platelet yield varied from 2.5 to 4.4 Χ 10ΉΉ in BCPP samples. The samples analyzed were sterile without any contamination. The different biochemical parameters were analyzed in detail. The observed post-transfusion platelet recovery and corrected count increment (CCI at 1 hour and 24 hours after BCPP transfusion were similar to that after SDP transfusion. Hence, we concluded that BCPP can be a low cost alternative to SDP in the times of emergencies like dengue and non-affordability by the patient for SDP.

  5. Effects of aspirin, carprofen, deracoxib, and meloxicam on platelet function and systemic prostaglandin concentrations in healthy dogs.

    Science.gov (United States)

    Blois, Shauna L; Allen, Dana G; Wood, R Darren; Conlon, Peter D

    2010-03-01

    To determine effects of therapeutic dosages of aspirin, carprofen, deracoxib, and meloxicam on platelet function and systemic prostaglandin concentrations in healthy dogs. 10 hound-crossbred dogs. Aspirin (10 mg/kg, PO, q 12 h), carprofen (4.4 mg/kg, PO, q 24 h), deracoxib (2 mg/kg, PO, q 24 h), meloxicam (0.1 mg/kg, PO, q 24 h), and a placebo were administered for 7 days in a random order to each of 10 healthy dogs; there was a 21-day washout period between subsequent treatments. One-stage prothrombin time (PT), activated partial thromboplastin time (aPTT), fibrinogen concentration, and plasma concentrations of thromboxane (TX)B(2) and 6-keto prostaglandin (PG)F(1alpha) were measured before and after treatment administration. Platelet function was assessed by use of a platelet-function analyzer and aggregation. Aspirin, carprofen, and meloxicam did not significantly affect platelet function. Deracoxib caused a mild decrease in platelet aggregation induced by 50microM ADP. Platelet number, Hct, PT, aPTT, and plasma TXB(2) and 6-keto PGF(1alpha) concentrations were unchanged after NSAID administration. Meloxicam administration resulted in a significant decrease in fibrinogen concentration, but results remained within the laboratory reference interval. Oral administration of commonly used NSAIDs at therapeutic dosages in healthy dogs did not alter plasma TXB(2) and 6-keto PGF(1alpha) concentrations. Deracoxib administration resulted in a minor abnormality in platelet aggregation. Anti-inflammatory doses of aspirin did not affect platelet function as measured by use of optical aggregometry and a platelet-function analyzer. Further evaluation of the effects of aspirin and cyclooxygenase-2-selective inhibitors on hemostasis should be performed.

  6. Evaluation of platelet thromboxane radioimmunoassay method to measure platelet life-span: Comparison with /sup 111/indium-platelet method

    International Nuclear Information System (INIS)

    Vallabhajosula, S.; Machac, J.; Badimon, L.; Lipszyc, H.; Goldsmith, S.J.; Fuster, V.

    1985-01-01

    The platelet activation during radiolabeling in vitro with Cr-51 and In-111 may affect the platelet life-span (PLS) in vivo. A new RIA method to measure PLS is being evaluated. Aspirin inhibits platelet thromboxane (TxA/sub 2/) by acetylating cyclooxygenase. The time required for the TxA/sub 2/ levels to return towards control values depends on the rate of new platelets entering circulation and is a measure of PLS. A single dose of aspirin (150mg) was given to 5 normal human subjects. Blood samples were collected for 2 days before aspirin and daily for 10 days. TxA/sub 2/ production in response to endogenous thrombin was studied by allowing 1 ml blood sample to clot at 37 0 C for 90 min. Serum TxB/sub 2/ (stable breakdown product of Tx-A/sub 2/) levels determined by RIA technique. The plot of TxB/sub 2/ levels (% control) against time showed a gradual increase. The PLS calculated by linear regression analysis assuming a 2-day lag period before cyclooxygenase recovery is 9.7 +- 2.37. In the same 5 subjects, platelets from a 50ml blood sample were labeled with /sup 111/In-tropolone in 2 ml autologous plasma. Starting at 1 hr after injection of labeled platelets, 10 blood samples were obtained over a 8 day period. The PLS calculated based on a linear regression analysis is 10.2 +. 1.4. The PLS measured from the rate of platelet disappearance from circulation and the rate of platelet regeneration into circulation are quite comparable in normal subjects. TxA/sub 2/ regeneration RIA may provide a method to measure PLS without administering radioactivity to patient

  7. Secreted Immunomodulatory Proteins of Staphylococcus aureus Activate Platelets and Induce Platelet Aggregation.

    Science.gov (United States)

    Binsker, Ulrike; Palankar, Raghavendra; Wesche, Jan; Kohler, Thomas P; Prucha, Josephine; Burchhardt, Gerhard; Rohde, Manfred; Schmidt, Frank; Bröker, Barbara M; Mamat, Uwe; Pané-Farré, Jan; Graf, Anica; Ebner, Patrick; Greinacher, Andreas; Hammerschmidt, Sven

    2018-04-01

    Staphylococcus aureus can cause bloodstream infections associated with infective endocarditis (IE) and disseminated intravascular coagulopathy (DIC). Both complications involve platelets. In view of an increasing number of antibiotic-resistant strains, new approaches to control systemic S. aureus infection are gaining importance. Using a repertoire of 52 recombinant S. aureus proteins in flow cytometry-based platelet activation and aggregation assays, we identified, in addition to the extracellular adherence protein Eap, three secreted staphylococcal proteins as novel platelet activating proteins. Eap and the chemotaxis inhibitory protein of S. aureus (CHIPS), the formyl peptide receptor-like 1 inhibitory protein (FLIPr) and the major autolysin Atl induced P-selectin expression in washed platelets and platelet-rich plasma. Similarly, AtlA, CHIPS and Eap induced platelet aggregation in whole blood. Fluorescence microscopy illustrated that P-selectin expression is associated with calcium mobilization and re-organization of the platelet actin cytoskeleton. Characterization of the functionally active domains of the major autolysin AtlA and Eap indicates that the amidase domain of Atl and the tandem repeats 3 and 4 of Eap are crucial for platelet activation. These results provide new insights in S. aureus protein interactions with platelets and identify secreted proteins as potential treatment targets in case of antibiotic-resistant S. aureus infection. Schattauer GmbH Stuttgart.

  8. Aspirin inhibition of platelet deposition at angioplasty sites: demonstration by platelet scintigraphy

    International Nuclear Information System (INIS)

    Cuningham, D.A.; Kumar, B.; Siegel, B.A.; Gilula, L.A.; Totty, W.G.; Welch, M.J.

    1984-01-01

    In-111 platelet scintigraphy was used to evaluate the effects of prior aspirin administration on the accumulation of In-111-labeled autologous platelets at sites of arterial injury resulting from iliac, femoral, or popliteal transluminal angioplasty in a nonrandomized study of 17 men. The degree of platelet localization at angioplasty sites was significantly less in nine men who had received aspirin in varying doses within the 4 days before angioplasty than in eight men who had not received aspirin for at least two weeks. The results suggest that aspirin treatment before angioplasty limits the early platelet deposition at the angioplasty site in men

  9. Platelet collection efficiencies of three different platelet-rich plasma preparation systems.

    Science.gov (United States)

    Aydin, Fatma; Pancar Yuksel, Esra; Albayrak, Davut

    2015-06-01

    Different systems have been used for the preparation of platelet-rich plasma (PRP), but platelet collection efficiencies of these systems are not clear. To evaluate the platelet collection efficiencies of three different PRP preparation systems. Blood samples were obtained from the same 16 volunteers for each system. The samples were centrifuged and PRP was prepared by three systems. The ratio of the total number of platelets in PRP to the total number of platelets of the venous blood sample of the patient expressed in percentage was named as platelet collection efficiency and calculated for each system. Mean platelet collection efficiencies were 66.6 (min: 56.9, max: 76.9), 58.3 (min: 27.3, max: 102.8), 50.8 (min: 27.2, max: 73) for top and bottom bag system, system using citrated tube, and the system using tube with Ficoll and cell extraction kit, respectively. Statistically significant difference was found only between the platelet collection efficiencies of systems using the tube with ficoll and cell extraction kit and the top and bottom bag system (p = 0.002). All three systems could be used for PRP preparation, but top and bottom bag system offers a slight advantage over the system using Ficoll and cell extraction kit regarding the platelet collection efficiency.

  10. Platelets and the innate immune system: Mechanisms of bacterial-induced platelet activation.

    OpenAIRE

    Cox, Dermot; Kerrigan, Steven W; Watson, Steve

    2011-01-01

    It has become clear that platelets are not simply cell fragments that can plug the leak in a damaged blood vessel, they are in fact key components in the innate immune system which is supported by the presence of Toll-like receptors (TLRs) on platelets. As the first responding cell to a site of injury they are well placed to direct the immune response to deal with any resulting exposure to pathogens. The response is triggered by bacteria binding to platelets which usually triggers platelet ac...

  11. On the predictive capabilities of CPA for applications in the chemical industry: Mulficomponent mixtures containing methyl-methacrylate, dimethyl-ether or acetic acid

    DEFF Research Database (Denmark)

    Tsivintzelis, Ioannis; Kontogeorgis, Georgios

    2014-01-01

    mixtures exhibiting vapor-liquid (VLE) and/or liquid-liquid (LLE) equilibrium. The first two cases include mixtures of methyl-methacrylate with acetone or methanol and dimethyl-ether with ethanol, respectively. In these two cases, the classical form of CPA is used. The third case involves aqueous mixtures...... for the acetic acid-water system for which different parameter sets at different temperatures can be recommended. Even with the use of CPA-HV mixing rules, modeling of the acetic acid-water system with few interaction parameters remains a challenging task. Excellent simultaneous VLE and LLE correlation...... is obtained for complex systems such as aqueous mixtures with ethers and esters. The multicomponent results are, with a few exceptions, very satisfactory, especially for the vapor-liquid equilibrium cases. For the demanding aqueous acetic acid-water containing systems, one parameter set is recommended...

  12. The CPA Equation of State and an Activity Coefficient Model for Accurate Molar Enthalpy Calculations of Mixtures with Carbon Dioxide and Water/Brine

    Energy Technology Data Exchange (ETDEWEB)

    Myint, P. C. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Hao, Y. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Firoozabadi, A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-03-27

    Thermodynamic property calculations of mixtures containing carbon dioxide (CO2) and water, including brines, are essential in theoretical models of many natural and industrial processes. The properties of greatest practical interest are density, solubility, and enthalpy. Many models for density and solubility calculations have been presented in the literature, but there exists only one study, by Spycher and Pruess, that has compared theoretical molar enthalpy predictions with experimental data [1]. In this report, we recommend two different models for enthalpy calculations: the CPA equation of state by Li and Firoozabadi [2], and the CO2 activity coefficient model by Duan and Sun [3]. We show that the CPA equation of state, which has been demonstrated to provide good agreement with density and solubility data, also accurately calculates molar enthalpies of pure CO2, pure water, and both CO2-rich and aqueous (H2O-rich) mixtures of the two species. It is applicable to a wider range of conditions than the Spycher and Pruess model. In aqueous sodium chloride (NaCl) mixtures, we show that Duan and Sun’s model yields accurate results for the partial molar enthalpy of CO2. It can be combined with another model for the brine enthalpy to calculate the molar enthalpy of H2O-CO2-NaCl mixtures. We conclude by explaining how the CPA equation of state may be modified to further improve agreement with experiments. This generalized CPA is the basis of our future work on this topic.

  13. [An experimental study on the Chinese lung adenocarcinoma cell clone CPA-Yang1-BR with brain metastasis potency in nude mice and in vivo imaging research].

    Science.gov (United States)

    Lei, Bei; Cao, Jie; Shen, Jie; Zhao, Lanxiang; Liang, Sheng; Meng, Qinggang; Xie, Wenhui; Yang, Shunfang

    2013-08-20

    Lung cancer is the leading cause of cancer-related death in men and women. It is also the most common cause of brain metastases. A brain metastasis model is difficult to be established because of the presence of the blood-brain barrier (BBB) and the lack of optimal methods for detecting brain metastasis in nude mice. Thus, the establishment of a Chinese lung adenocarcinoma cell line and its animal model with brain metastasis potency and in vivo research is of great significance. CPA-Yang1 cells were obtained from a patient with human lung adenocarcinoma by lentiviral vector-mediated transfection of green fluorescence protein. Intracardiac inoculation of the cells was performed in nude mice, and brain metastatic lesions were detected using micro ¹⁸F FDG-PET/CT scanners, small animal in vivo imaging system for fluorescence, radionuclide and X ray fused imaging, magnetic resonance imaging (MRI) with sense body detection, and resection. The samples were divided into two parts for cell culture and histological diagnosis. The process was repeated in vivo and in vitro for four cycles to obtain a novel cell clone, CPA-Yang1-BR. A novel cell clone, CPA-Yang1-BR, was obtained with a brain metastatic rate of 50%. The use of MRI for the detection of brain metastases has obvious advantages. An experimental Chinese lung adenocarcinoma cell clone (CPA-Yang1-BR) and its animal model with brain metastasis potency in nude mice were established. MRI with sense body or micro MRI may be used as a sensitive, accurate, and noninvasive method to detect experimental brain metastases in intact live immunodeficient mice. The results of this study may serve as a technical platform for brain metastases from lung adenocarcinoma.

  14. Physiopathology of blood platelets and development of platelet substitutes. Progress report, August 1, 1975--July 31, 1976

    Energy Technology Data Exchange (ETDEWEB)

    Baldini, M G

    1976-04-28

    Progress is reported on studies on the physiology of blood platelets in thrombocytopenic patients and rabbits. Methods for the detection of platelet antibodies and the preservation of platelets in vitro were investigated. Studies on the effect of low doses of x irradiation (up to 1000 R) on platelet function indicate that platelets exposed to ionizing radiation have increased functional activity. A list is included of publications that report the results of the studies in detail.

  15. Physiopathology of blood platelets and development of platelet substitutes. Progress report, August 1, 1975--July 31, 1976

    International Nuclear Information System (INIS)

    Baldini, M.G.

    1976-01-01

    Progress is reported on studies on the physiology of blood platelets in thrombocytopenic patients and rabbits. Methods for the detection of platelet antibodies and the preservation of platelets in vitro were investigated. Studies on the effect of low doses of x irradiation (up to 1000 R) on platelet function indicate that platelets exposed to ionizing radiation have increased functional activity. A list is included of publications that report the results of the studies in detail

  16. Mapuche Herbal Medicine Inhibits Blood Platelet Aggregation

    Directory of Open Access Journals (Sweden)

    Susan Skanderup Falkenberg

    2012-01-01

    Full Text Available 12 plant species traditionally used by the Mapuche people in Chile to treat wounds and inflammations have been evaluated for their direct blood platelet inhibition. Seven of the 12 tested plant species showed platelet inhibitory effect in sheep blood, and four of these were also able to inhibit the ADP- (5.0 μM and collagen- (2.0 μg/mL induced aggregations in human blood. These four species in respective extracts (in brackets were Blechnum chilense (MeOH, Luma apiculata (H2O, Amomyrtus luma (DCM : MeOH 1 : 1 and Cestrum parqui (DCM : MeOH 1 : 1. The platelet aggregating inhibitory effects of A. luma (DCM : MeOH 1 : 1, and L. apiculata (H2O were substantial and confirmed by inhibition of platelet surface activation markers.

  17. Platelet-Rich Plasma Increases Pigmentation.

    Science.gov (United States)

    Uysal, Cagri A; Ertas, Nilgun Markal

    2017-11-01

    Platelet-rich plasma (PRP) is an autologous solution of plasma containing 4 to 7 times the baseline concentration of human platelets. Platelet-rich plasma has been widely popular in facial rejuvenation to attenuate wrinkles and has been practically used. The authors have been encountering various patients of increased hiperpigmentation following PRP applications that were performed to attenuate the postinflammatory hiperpigmentation especially after laser treatment. The authors have been using PRP for facial rejuvenation in selected patients and in 1 patient the authors have encountered increased pigmentation over the pigmented skin lesions that were present before the application. The authors recommend that the PRP might increase pigmentation especially in the face region and precautions might be taken before and after the application. Platelet-rich plasma should not be used for the treatment of post inflammatory hiperpigmentation.

  18. Storage of human platelets by freezing

    Energy Technology Data Exchange (ETDEWEB)

    Kim, B K; Tanoue, K; Baldini, M G

    1976-01-01

    Prolonged, probably indefinite storage of viable and functional human platelets is now possible by freezing with dimethylsulfoxide (DMSO). The platelets have a nearly normal survival upon reinfusion and are capable of sustained hemostatic effectiveness in thrombocytopenic patients. Adaptation of the freezing technique for large-scale usage has more recently been achieved. The method is mainly based on the following principles: (1) use of plasma for suspension of the platelet concentrate; (2) gradual addition (0.5% every 2 min) of DMSO to a final concentration of 5% and its gradual removal; (3) a slow cooling rate of about 1/sup 0/C per min and rapid thawing (in 1 min); (4) use of a polyolefin plastic bag for freezing; (5) a washing medium of 20% plasma in Hanks' balanced salt solution; (6) final resuspension of the platelets in 50% plasma in Hanks' solution.

  19. Effects of drugs on platelet function.

    Science.gov (United States)

    Morse, E E

    1977-01-01

    Numerous drugs and chemicals affect the function of human blood platelets. The mechanism of action of some medications is partly understood. Aspirin is the most frequently involved drug. It appears to interfere with the platelet release reaction by acetylation of a platelet membrane protein which may be involved in the synthesis of prostaglandins. Other anti-inflammatory drugs, including indomethacin, phenylbutazone, ibuprophen (Motrin) and clonixin, also interfere with the release reaction but have a shorter acting course than aspirin. Some drugs stimulate adenylcyclase (gliclazide) or block phosphodiesterase, (dipyridamole, caffeine) both of which actions lead to an increase in adenosine cyclic 3':5' monophosphate (cAMP) and decrease aggregation by adenosine diphosphate (ADP). These interactions should be known to clinical scientists since patients using these medicaments may manifest abnormal platelet function tests in the laboratory and mild hemorrhagic syndromes in the clinic.

  20. Mapuche herbal medicine inhibits blood platelet aggregation.

    Science.gov (United States)

    Falkenberg, Susan Skanderup; Tarnow, Inge; Guzman, Alfonso; Mølgaard, Per; Simonsen, Henrik Toft

    2012-01-01

    12 plant species traditionally used by the Mapuche people in Chile to treat wounds and inflammations have been evaluated for their direct blood platelet inhibition. Seven of the 12 tested plant species showed platelet inhibitory effect in sheep blood, and four of these were also able to inhibit the ADP- (5.0 μM) and collagen- (2.0 μg/mL) induced aggregations in human blood. These four species in respective extracts (in brackets) were Blechnum chilense (MeOH), Luma apiculata (H(2)O), Amomyrtus luma (DCM : MeOH 1 : 1) and Cestrum parqui (DCM : MeOH 1 : 1). The platelet aggregating inhibitory effects of A. luma (DCM : MeOH 1 : 1), and L. apiculata (H(2)O) were substantial and confirmed by inhibition of platelet surface activation markers.

  1. Platelet Disorders: MedlinePlus Health Topic

    Science.gov (United States)

    ... Thromobocytopenia - drug-induced (Medical Encyclopedia) Also in Spanish Topic Image MedlinePlus Email Updates Get Platelet Disorders updates ... Willebrand disease Show More Show Less Related Health Topics Bleeding Disorders Blood Clots Blood Count Tests Blood ...

  2. Differential effects of platelet rich plasma and washed platelets on the proliferation of mouse MSC cells.

    Science.gov (United States)

    Duan, Jianmin; Kuang, Wei; Tan, Jiali; Li, Hongtao; Zhang, Yi; Hirotaka, Kikuchi; Tadashi, Katayama

    2011-04-01

    Multipotent mesenchymal stem cell (MSC) therapies are being tested clinically for a variety of disorders. However, despite the remarkable clinical advancements in this field, most applications still use traditional culture media containing fetal bovine serum. Platelet-rich plasma (PRP) appears as a novel application for tissue engineering and its effect on bone healing is thought to be mainly dependent on the proliferation promoting function, with the molecular mechanisms largely unknown. In this study, mouse osteogenic progenitor mesenchymal stem cells (MSCs) were cultured in PRP or washed platelet (WPLT)-treated wells or in untreated wells, and analyzed on cycloxygenase 2 (COX2) expression (qRT-PCR), cell growth (MTT assay) and cell differentiation (alkaline phosphatase activity). The results showed that PRP and WPLT stimulated cell growth similarly in the first 6 days, together with the steady induction of COX2 and PGE2. 10 μmol/l celecoxib (an inhibitor of COX2) significantly inhibited the pro-proliferation effects. Interestingly, WPLT had stronger effects than PRP in proliferation at the later time points (6-9 days). ALP activity assay and collagen 1a expression revealed PRP had a mild but statistically significant pro-differentiation effect, while no obvious effects observed in WLPT group. In summary, PRP stimulates initial growth of MSCs in a COX2 partially dependent manner and the less obvious osteogenic differentiation promoting effects of WPLT strongly indicates WPLT rather than the PRP should be the optional choice for expanding MSCs in vitro for clinical use.

  3. Platelet-Poor Plasma as a Supplement for Fibroblasts Cultured in Platelet-Rich Fibrin

    Directory of Open Access Journals (Sweden)

    Luiz Alexandre Chisini

    2017-01-01

    Full Text Available The aim of this study was to evaluate the proliferation and adhesion of mesenchymal cells (3T3/NIH in Dulbecco’s Modified Eagle Medium (DMEM supplemented with Platelet-Poor Plasma (PPP in a Platelet-Rich Fibrin (PRF scaffold. Human blood was obtained and processed in a centrifuge considering the equation G=1.12xRx (RPM/1000² to obtain PRF and PPP. Cell adhesion and maintenance analyses were performed by MTT assays in a 96 well plate with supplemented DMEM: PPP (90:10 for 24 hours. Besides, the PRF was deposited in a 48 well plate and 10x104 cells were seeded above each PRF (n=3 with 800μl of DMEM: PPP (90:10 and cultured for 7 days. Histological analysis and the immunohistochemical staining for Vimentin were performed. Results were analyzed by one-way ANOVA in Stata12®. A significant decrease (p0.05. Fibroblasts culture for 7 days in PRF supplemented with PPP 10% was possible, showing positive staining for Vimentin. Therefore, PPP cell supplementation decreased the initial adhesion of cells but was able to maintain the proliferation of adhered cells and able to support their viability in PRF. It seems that this method has many clinical advantages since it provides an autologous and natural scaffold with their respective supplement for cell culture by only one process, without using xenogeneic compounds. This could improve the potential of clinical translational therapies based on the use of PRF cultured cells, promoting the regenerative potential for future use in medicine and dentistry.

  4. Stimulus-response coupling in platelets

    International Nuclear Information System (INIS)

    Huang, E.M.

    1986-01-01

    To understand the mechanism of stimulus-response coupling in platelets, the potentiating effect of succinate and lithium on platelet activation was examined. The action of succinate was immediate; preincubation with succinate did not lead to desensitization. Succinate was comparable to ADP in lowering cAMP levels previously elevated by PGl 2 . Since inhibition of cAMP is not a prerequisite for platelet activation, the mechanism of potentiation of succinate remains undefined. Lithium has also been shown to inhibit adenylate cyclase in PGl 2 -pretreated platelets. Lithium, however, can also inhibit inositol phosphate (InsP) phosphatase and lead to an accumulation of InsP. In human platelets, lithium also enhanced the thrombin-induced accumulation of [ 3 H]inositol-labelled inositol trisphosphate (InsP 3 ), and inositol bisphosphate (InsP 2 ). One hour after thrombin addition, all 3 inositol phosphates returned to near basal levels. In the presence of lithium, while labelled InsP 2 and InsP 3 returned to their respective basal levels, the InsP level remained elevated, consistent with the known inhibitory effect of lithium on InsP phosphatase. In thrombin-stimulated platelets prelabeled with [ 32 P]phosphate, lithium led to a decrease in labelled phosphatidylinositol 4-phosphate (PtdIns4P) as well as an enhanced production of labelled lysophosphatidylinositol, suggesting multiple effects of lithium on platelet phosphoinositide metabolism. These observed effects, however, occurred too slowly to be the mechanism by which lithium potentiated agonist-induced platelet activation. To study the agonist-receptor interaction, the effect of the specific, high affinity thrombin inhibitor, hirudin, on thrombin-induced accumulation of [ 3 H]inositol-labelled inositol phosphates was studied

  5. Effects of irradiation on platelet function

    International Nuclear Information System (INIS)

    Rock, G.; Adams, G.A.; Labow, R.S.

    1988-01-01

    Current medical practice involves the irradiation of blood components, including platelet concentrates, before their administration to patients with severe immunosuppression. The authors studied the effect of irradiation on in vitro platelet function and the leaching of plasticizers from the bag, both immediately and after 5 days of storage. The platelet count, white cell count, pH, glucose, lactate, platelet aggregation and release reaction, and serotonin uptake were not altered by the irradiation of random-donor or apheresis units with 2000 rads carried out at 0 and 24 hours and 5 days after collection. The leaching of di(2-ethylhexyl)phthalate from the plastic bags followed by the conversion to mono(2-ethylhexyl)phthalate was not increased by irradiation. Therefore, it is possible to irradiate platelet concentrates on the day of collection and subsequently store them for at least 5 days while maintaining in vitro function. This procedure could have considerable benefit for blood banks involved in the provision of many platelet products

  6. Glycoprotein biosynthesis by human normal platelets

    International Nuclear Information System (INIS)

    Rodriguez, P.; Bello, O.; Apitz-Castro, R.

    1987-01-01

    Incorporation of radioactive Man, Gal, Fuc, Glc-N, and NANA into washed human normal platelets and endogenous glycoproteins has been found. Both parameters were time dependent. Analysis of hydrolyzed labeled glycoproteins by paper chromatography revealed that the radioactive monosaccharide incubated with the platelets had not been converted into other sugars. Acid hydrolysis demonstrates the presence of a glycosidic linkage. All the effort directed to the demonstration of the existence of a lipid-sugar intermediate in intact human platelets yielded negative results for Man and Glc-N used as precursors. The incorporation of these sugars into glycoproteins is insensitive to bacitracin, suggesting no involvement of lipid-linked saccharides in the synthesis of glycoproteins in human blood platelets. The absence of inhibition of the glycosylation process in the presence of cycloheximide suggests that the sugars are added to proteins present in the intact platelets. These results support the contention that glycoprotein biosynthesis in human blood platelets observed under our experimental conditions is effected through direct sugar nucleotide glycosylation

  7. Assessment of quality of platelets preserved in plasma and platelet additive solution: A Malaysian experience

    Directory of Open Access Journals (Sweden)

    Munirah Binti Mokhtar

    2016-01-01

    Full Text Available Background: A use of platelet additives solution (PAS improves storage conditions so as to give increased shelf life to platelets and to maintain hemostatic function. Objective: The present study was aimed to compare in vitro quality of platelet rich plasma (PRP-derived platelet concentrate (PC during extended period of storage in plasma and in additive solution (Composol PS and Fresenius. Study Design: Randomized 19 PCs each were used in the study for plasma and PAS as the storage medium. The measurement parameters, including pH, total white blood cell (WBC count, total platelet count, and platelet activation rate, were studied on day 1, day 5, and day 8 of the storage period. The sterility test was carried out on the eighth day of storage. Results: pH of PC suspended in PAS was significantly lower as compared to that in plasma (P < 0.001 for all the three days of sampling. The WBC count, both in plasma and in PAS, showed an acceptable values of being <0.2 Χ 10 9 /unit during the storage period. Platelet count in PAS was higher as compared to that in plasma, though it was not statistically significant. While both the groups showed increased platelet activation rate during the storage, the PCs suspended in PAS showed significantly higher platelet activation rate (p0.001. Results from sterility test showed no bacterial growth in the PCs in both the groups. Conclusion: Most parameters studied on platelet storage in suspending medium of native plasma and PAS remained well within the acceptable limits. However, the pH values and platelet activation rate significantly differed in PAS as compared with plasma.

  8. Quantification of platelets obtained by different centrifugation protocols in SHR rats

    Directory of Open Access Journals (Sweden)

    João Alberto Yazigi Junior

    2015-12-01

    Full Text Available ABSTRACT OBJECTIVE: To quantify the platelet concentration in the blood of SHR rats, by means of different centrifugation protocols, and to evaluate what the most effective method for obtaining platelets is. METHODS: We used 40 male rats of the isogenic SHR lineage. The animals were divided into three groups: control, using whole blood without centrifugation; single centrifugation, using whole blood subjected to a single centrifugation at 200 × gand 400 × g; and double centrifugation, using whole blood subjected one centrifugation at different rotations, followed by collection of whole plasma subjected to another centrifugation at different rotations: 200 × g+ 200 ×g; 200 × g+ 400 × g; 200 × g+ 800 × g; 400 ×g+ 400 × g; 400 × g+ 800 × g. Samples of 3 ml of blood were drawn from each animal by means of cardiac puncture. The blood was stored in Vacutainer collection tubes containing 3.2% sodium citrate. The blood from the control group animals was analyzed without being subjected to centrifugation. After the blood from the other groups of animals had been subjected to centrifugation, the whole plasma was collected and subjected to platelet counting in the lower third of the sample. RESULTS: We obtained greatest platelet enrichment in the subgroup with two centrifugations comprising 400 × gfor 10 min + 400 ×gfor 10 min, in which the mean platelet concentration was 11.30 times higher than that of the control group. CONCLUSION: It was possible to obtain a high platelet concentration using viable simple techniques, by means of centrifugation of whole blood and use of commonly used materials. The most effective method for obtaining platelet concentrate was found in samples subjected to two centrifugations.

  9. Platelets Proteomic Profiles of Acute Ischemic Stroke Patients.

    Directory of Open Access Journals (Sweden)

    Ozge Cevik

    Full Text Available Platelets play a crucial role in the pathogenesis of stroke and antiplatelet agents exist for its treatment and prevention. Through the use of LC-MS based protein expression profiling, platelets from stroke patients were analyzed and then correlated with the proteomic analyses results in the context of this disease. This study was based on patients who post ischemic stroke were admitted to hospital and had venous blood drawn within 24 hrs of the incidence. Label-free protein expression analyses of the platelets' tryptic digest was performed in triplicate on a UPLC-ESI-qTOF-MS/MS system and ProteinLynx Global Server (v2.5, Waters was used for tandem mass data extraction. The peptide sequences were searched against the reviewed homo sapiens database (www.uniprot.org and the quantitation of protein variation was achieved through Progenesis LC-MS software (V4.0, Nonlinear Dynamics. These Label-free differential proteomics analysis of platelets ensured that 500 proteins were identified and 83 of these proteins were found to be statistically significant. The differentially expressed proteins are involved in various processes such as inflammatory response, cellular movement, immune cell trafficking, cell-to-cell signaling and interaction, hematological system development and function and nucleic acid metabolism. The expressions of myeloperoxidase, arachidonate 12-Lipoxygenase and histidine-rich glycoprotein are involved in cellular metabolic processes, crk-like protein and ras homolog gene family member A involved in cell signaling with vitronectin, thrombospondin 1, Integrin alpha 2b, and integrin beta 3 involved in cell adhesion. Apolipoprotein H, immunoglobulin heavy constant gamma 1 and immunoglobulin heavy constant gamma 3 are involved in structural, apolipoprotein A-I, and alpha-1-microglobulin/bikunin precursor is involved in transport, complement component 3 and clusterin is involved in immunity proteins as has been discussed. Our data provides

  10. Platelet inhibition by nitrite is dependent on erythrocytes and deoxygenation.

    Directory of Open Access Journals (Sweden)

    Sirada Srihirun

    Full Text Available Nitrite is a nitric oxide (NO metabolite in tissues and blood, which can be converted to NO under hypoxia to facilitate tissue perfusion. Although nitrite is known to cause vasodilation following its reduction to NO, the effect of nitrite on platelet activity remains unclear. In this study, the effect of nitrite and nitrite+erythrocytes, with and without deoxygenation, on platelet activity was investigated.Platelet aggregation was studied in platelet-rich plasma (PRP and PRP+erythrocytes by turbidimetric and impedance aggregometry, respectively. In PRP, DEANONOate inhibited platelet aggregation induced by ADP while nitrite had no effect on platelets. In PRP+erythrocytes, the inhibitory effect of DEANONOate on platelets decreased whereas nitrite at physiologic concentration (0.1 µM inhibited platelet aggregation and ATP release. The effect of nitrite+erythrocytes on platelets was abrogated by C-PTIO (a membrane-impermeable NO scavenger, suggesting an NO-mediated action. Furthermore, deoxygenation enhanced the effect of nitrite as observed from a decrease of P-selectin expression and increase of the cGMP levels in platelets. The ADP-induced platelet aggregation in whole blood showed inverse correlations with the nitrite levels in whole blood and erythrocytes.Nitrite alone at physiological levels has no effect on platelets in plasma. Nitrite in the presence of erythrocytes inhibits platelets through its reduction to NO, which is promoted by deoxygenation. Nitrite may have role in modulating platelet activity in the circulation, especially during hypoxia.

  11. Superoxide Dismutase 2 is dispensable for platelet function.

    Science.gov (United States)

    Fidler, Trevor P; Rowley, Jesse W; Araujo, Claudia; Boudreau, Luc H; Marti, Alex; Souvenir, Rhonda; Dale, Kali; Boilard, Eric; Weyrich, Andrew S; Abel, E Dale

    2017-10-05

    Increased intracellular reactive oxygen species (ROS) promote platelet activation. The sources of platelet-derived ROS are diverse and whether or not mitochondrial derived ROS, modulates platelet function is incompletely understood. Studies of platelets from patients with sickle cell disease, and diabetes suggest a correlation between mitochondrial ROS and platelet dysfunction. Therefore, we generated mice with a platelet specific knockout of superoxide dismutase 2 (SOD2-KO) to determine if increased mitochondrial ROS increases platelet activation. SOD2-KO platelets demonstrated decreased SOD2 activity and increased mitochondrial ROS, however total platelet ROS was unchanged. Mitochondrial function and content were maintained in non-stimulated platelets. However SOD2-KO platelets demonstrated decreased mitochondrial function following thrombin stimulation. In vitro platelet activation and spreading was normal and in vivo, deletion of SOD2 did not change tail-bleeding or arterial thrombosis indices. In pathophysiological models mediated by platelet-dependent immune mechanisms such as sepsis and autoimmune inflammatory arthritis, SOD2-KO mice were phenotypically identical to wildtype controls. These data demonstrate that increased mitochondrial ROS does not result in platelet dysfunction.

  12. Advances and controversies in neonatal ICU platelet transfusion practice.

    Science.gov (United States)

    Christensen, Robert D

    2008-01-01

    Some of the platelet transfusions currently given to NICU patients are unnecessary and convey no benefits. Although ordered with good intentions, unnecessary platelet transfusions carry known and unknown risks. Identifying and eliminating any unnecessary platelet transfusions in NICUs would be a step toward better care, lower costs, and more careful preservation of blood component resources. A renewed interest in platelet transfusion studies is needed, if essential data is to be gathered to improve NICU platelet transfusion practice. Retrospective studies can be of value: for instance, seeking associations between bleeding events and platelet counts can suggest the possibility of cause and effect relationships. Such studies might identify approximate platelet count levels that convey high hemorrhagic risk and might help focus future prospective trials. Prospective indirect studies also can be of value, for instance, measuring the template bleeding time and the PFA-100 closure time as a function of platelet count and perhaps as a function of circulating platelet mass, and would provide new information with relevance to platelet transfusion benefits. Such studies might give a better awareness of how low the platelet count can fall before platelet plug formation is impaired. It seems inescapable, however, that new, multicentered, randomized, prospective studies are needed, where NICU patients are assigned different platelet transfusion triggers and then carefully tracked for bleeding events and long-term neurodevelopmental outcomes. Only that type of study is likely to generate the evidence base needed for widespread implementation of improvements in NICU platelet transfusion practice.

  13. Collagen induced aggregation of platelets and release of 14C serotonin from platelets depending on temperature and pH during in vitro storage of platelets

    International Nuclear Information System (INIS)

    Krause, J.

    1978-01-01

    The paper investigates collagen-induced platelet aggregation and 14 C serotonin release in dependence of age, temperature, and pH value during the storage of the conserved platelets. The optimum pH (with adjusted CO 2 /air mixture) for platelet storage is found to be pH 6.9. The optimum temperature for platelet storage is 4-8 0 C. After 12, 24, or 48 hours of storage at pH 6.9 and 4-8 0 C and subsequent heating of the platelet-rich plasma to 37 0 C for 30 minutes, the values determined for collagen-induced platelet aggregation and 14 C serotonin release rarely differed from the initial values before storage. Cold-induced spontaneous platelet aggregation and serotonin release of the platelets stored at 4-8 0 C can be avoided by 30-60 minutes pre-incubation of the platelets at 37 0 C before transfusions. The in vitro findings for collagen-induced platelet aggregation and 14 C serotonin release indicate that platelet storage for 24-48 hours at pH 6.9 and 4-8 0 C may be permissible also for clinical purposes. The problem remains open whether the clinical effect of these platelets is still sufficient after 48 hours of storage, but literature findings suggest that this may well be the case. (orig.) [de

  14. Responsiveness of platelets during storage studied with flow cytometry--formation of platelet subpopulations and LAMP-1 as new markers for the platelet storage lesion.

    Science.gov (United States)

    Södergren, A L; Tynngård, N; Berlin, G; Ramström, S

    2016-02-01

    Storage lesions may prevent transfused platelets to respond to agonists and arrest bleeding. The aim of this study was to evaluate and quantify the capacity of platelet activation during storage using flow cytometry and new markers of platelet activation. Activation responses of platelets prepared by apheresis were measured on days 1, 5, 7 and 12. In addition, comparisons were made for platelet concentrates stored until swirling was affected. Lysosome-associated membrane protein-1 (LAMP-1), P-selectin and phosphatidylserine (PS) exposure were assessed by flow cytometry on platelets in different subpopulations in resting state or following stimulation with platelet agonists (cross-linked collagen-related peptide (CRP-XL), PAR1- and PAR4-activating peptides). The ability to form subpopulations upon activation was significantly decreased already at day 5 for some agonist combinations. The agonist-induced exposure of PS and LAMP-1 also gradually decreased with time. Spontaneous exposure of P-selectin and PS increased with time, while spontaneous LAMP-1 exposure was unchanged. In addition, agonist-induced LAMP-1 expression clearly discriminated platelet concentrates with reduced swirling from those with retained swirling. This suggests that LAMP-1 could be a good marker to capture changes in activation capacity in stored platelets. The platelet activation potential seen as LAMP-1 exposure and fragmentation into platelet subpopulations is potential sensitive markers for the platelet storage lesion. © 2015 International Society of Blood Transfusion.

  15. Redox Proteomics and Platelet Activation: Understanding the Redox Proteome to Improve Platelet Quality for Transfusion

    Science.gov (United States)

    Sonego, Giona; Abonnenc, Mélanie; Tissot, Jean-Daniel; Prudent, Michel; Lion, Niels

    2017-01-01

    Blood banks use pathogen inactivation (PI) technologies to increase the safety of platelet concentrates (PCs). The characteristics of PI-treated PCs slightly differ from those of untreated PCs, but the underlying reasons are not well understood. One possible cause is the generation of oxidative stress during the PI process. This is of great interest since reactive oxygen species (ROS) act as second messengers in platelet functions. Furthermore, there are links between protein oxidation and phosphorylation, another mechanism that is critical for cell regulation. Current research efforts focus on understanding the underlying mechanisms and identifying new target proteins. Proteomics technologies represent powerful tools for investigating signaling pathways involving ROS and post-translational modifications such as phosphorylation, while quantitative techniques enable the comparison of the platelet resting state versus the stimulated state. In particular, redox cysteine is a key player in platelet activation upon stimulation by different agonists. This review highlights the experiments that have provided insights into the roles of ROS in platelet function and the implications for platelet transfusion, and potentially in diseases such as inflammation and platelet hyperactivity. The review also describes the implication of redox mechanism in platelet storage considerations. PMID:28208668

  16. Nephropathy in type 1 diabetes is associated with increased circulating activated platelets and platelet hyperreactivity

    DEFF Research Database (Denmark)

    Tarnow, Inge; Michelson, Alan D.; Barnard, Marc R.

    2009-01-01

    Patients with diabetes mellitus (DM) have increased platelet activation compared to non-diabetic controls. Platelet hyperreactivity has been associated with adverse cardiovascular outcomes in Type 2 DM, and with diabetic nephropathy. We investigated the relationship between platelet activation...... and nephropathy in Type 1 DM. Patients with Type 1 DM and diabetic nephropathy (n = 35), age- and sex-matched Type 1 DM patients with persistent normoalbuminuria (n = 51), and healthy age- and sex-matched controls (n = 30) were studied. Platelet surface P-selectin, platelet surface activated GPIIb/IIIa, monocyte...... controls (P = 0.0075). There were no differences between groups in activated GPIIb/IIIa or in response to TRAP at any end-point. More patients with nephropathy received aspirin (71.4%) compared to normoalbuminuric patients (27.4%) (P Type 1 diabetic nephropathy, as compared with normoalbuminuria...

  17. Platelet-rich fibrin or platelet-rich plasma – which one is better? an opinion

    Directory of Open Access Journals (Sweden)

    Shweta Bansal

    2017-01-01

    Full Text Available The healing of hard and soft tissue in mediated by a wide range of intracellular and extracellular events that are regulated by signaling proteins. Platelets can play a crucial role in periodontal regeneration as they are the reservoirs of growth factors and cytokines which are the key factors for regeneration of bone and maturation of soft tissue. Platelet-rich plasma (PRP is first generation platelet concentrate. However, the short duration of cytokine release and its poor mechanical properties have resulted in search of new material. Platelet-rich fibrin (PRF is a natural fibrin-based biomaterial prepared from an anticoagulant-free blood harvest without any artificial biochemical modification (no bovine thrombin is required that allows obtaining fibrin membranes enriched with platelets and growth factors. The slow polymerization during centrifugation, fibrin-based structure, ease of preparation, minimal expense makes PRF somewhat superior in some aspect to PRP.

  18. Platelets promote osteosarcoma cell growth through activation of the platelet-derived growth factor receptor-Akt signaling axis.

    Science.gov (United States)

    Takagi, Satoshi; Takemoto, Ai; Takami, Miho; Oh-Hara, Tomoko; Fujita, Naoya

    2014-08-01

    The interactions of tumor cells with platelets contribute to the progression of tumor malignancy, and the expression levels of platelet aggregation-inducing factors positively correlate with the metastatic potential of osteosarcoma cells. However, it is unclear how tumor-platelet interaction contributes to the proliferation of osteosarcomas. We report here that osteosarcoma-platelet interactions induce the release of platelet-derived growth factor (PDGF) from platelets, which promotes the proliferation of osteosarcomas. Co-culture of platelets with MG63 or HOS osteosarcoma cells, which could induce platelet aggregation, enhanced the proliferation of each cell line in vitro. Analysis of phospho-antibody arrays revealed that co-culture of MG63 cells with platelets induced the phosphorylation of platelet derived growth factor receptor (PDGFR) and Akt. The addition of supernatants of osteosarcoma-platelet reactants also increased the growth of MG63 and HOS cells as well as the level of phosphorylated-PDGFR and -Akt. Sunitinib or LY294002, but not erlotinib, significantly inhibited the platelet-induced proliferation of osteosarcoma cells, indicating that PDGF released from platelets plays an important role in the proliferation of osteosarcomas by activating the PDGFR and then Akt. Our results suggest that inhibitors that specifically target osteosarcoma-platelet interactions may eradicate osteosarcomas. © 2014 The Authors. Cancer Science published by Wiley Publishing Asia Pty Ltd on behalf of Japanese Cancer Association.

  19. Aspirin resistance may be identified by miR-92a in plasma combined with platelet distribution width

    DEFF Research Database (Denmark)

    Binderup, Helle Glud; Houlind, Kim; Madsen, Jonna Skov

    2016-01-01

    OBJECTIVE: Aspirin is a widely used drug for prevention of thrombotic events in cardiovascular patients, but approximately 25% of patients experience insufficient platelet inhibition due to aspirin, and remain in risk of cardiovascular events. This study aimed to investigate the value...... of circulating miR-92a and platelet size as biomarkers of the individual response to aspirin therapy. METHODS: Blood samples were collected from 50 healthy blood donors without antithrombotic medication and 50 patients with intermittent claudication on daily aspirin therapy. Based on results from the arachidonic...... acid stimulated aggregation test on Multiplate®analyzer (ASPItest), patients were defined as aspirin resistant (n=10) or aspirin responders (n=40). Plasma levels of miR-92a were evaluated by RT-qPCR analysis and platelet distribution width (PDW) was used to assess platelet size variability. Receiver...

  20. Platelets of patients with chronic kidney disease demonstrate deficient platelet reactivity in vitro

    Directory of Open Access Journals (Sweden)

    van Bladel Esther R

    2012-09-01

    Full Text Available Abstract Background In patients with chronic kidney disease studies focusing on platelet function and properties often are non-conclusive whereas only few studies use functional platelet tests. In this study we evaluated a recently developed functional flow cytometry based assay for the analysis of platelet function in chronic kidney disease. Methods Platelet reactivity was measured using flow cytometric analysis. Platelets in whole blood were triggered with different concentrations of agonists (TRAP, ADP, CRP. Platelet activation was quantified with staining for P-selectin, measuring the mean fluorescence intensity. Area under the curve and the concentration of half-maximal response were determined. Results We studied 23 patients with chronic kidney disease (9 patients with cardiorenal failure and 14 patients with end stage renal disease and 19 healthy controls. Expression of P-selectin on the platelet surface measured as mean fluorescence intensity was significantly less in chronic kidney disease patients compared to controls after maximal stimulation with TRAP (9.7 (7.9-10.8 vs. 11.4 (9.2-12.2, P = 0.032, ADP (1.6 (1.2-2.1 vs. 2.6 (1.9-3.5, P = 0.002 and CRP (9.2 (8.5-10.8 vs. 11.5 (9.5-12.9, P = 0.004. Also the area under the curve was significantly different. There was no significant difference in half-maximal response between both groups. Conclusion In this study we found that patients with chronic kidney disease show reduced platelet reactivity in response of ADP, TRAP and CRP compared to controls. These results contribute to our understanding of the aberrant platelet function observed in patients with chronic kidney disease and emphasize the significance of using functional whole blood platelet activation assays.

  1. Platelet receptor polymorphisms do not influence Staphylococcus aureus–platelet interactions or infective endocarditis

    Science.gov (United States)

    Daga, Shruti; Shepherd, James G.; Callaghan, J. Garreth S.; Hung, Rachel K.Y.; Dawson, Dana K.; Padfield, Gareth J.; Hey, Shi Y.; Cartwright, Robyn A.; Newby, David E.; Fitzgerald, J. Ross

    2011-01-01

    Cardiac vegetations result from bacterium–platelet adherence, activation and aggregation, and are associated with increased morbidity and mortality in infective endocarditis. The GPIIb/IIIa and FcγRIIa platelet receptors play a central role in platelet adhesion, activation and aggregation induced by endocarditis pathogens such as Staphylococcus aureus, but the influence of known polymorphisms of these receptors on the pathogenesis of infective endocarditis is unknown. We determined the GPIIIa platelet antigen PlA1/A2 and FcγRIIa H131R genotype of healthy volunteers (n = 160) and patients with infective endocarditis (n = 40), and investigated the influence of these polymorphisms on clinical outcome in infective endocarditis and S. aureus–platelet interactions in vitro. Platelet receptor genotype did not correlate with development of infective endocarditis, vegetation characteristics on echocardiogram or the composite clinical end-point of embolism, heart failure, need for surgery or mortality (P > 0.05 for all), even though patients with the GPIIIa PlA1/A1 genotype had increased in vivo platelet activation (P = 0.001). Furthermore, neither GPIIIa PlA1/A2 nor FcγRIIa H131R genotype influenced S. aureus-induced platelet adhesion, activation or aggregation in vitro (P > 0.05). Taken together, our data suggest that the GPIIIa and FcγRIIa platelet receptor polymorphisms do not influence S. aureus–platelet interactions in vitro or the clinical course of infective endocarditis. PMID:21044892

  2. Apheresis platelet concentrates contain platelet-derived and endothelial cell-derived microparticles.

    Science.gov (United States)

    Rank, A; Nieuwland, R; Liebhardt, S; Iberer, M; Grützner, S; Toth, B; Pihusch, R

    2011-02-01

    Microparticles (MP) are membrane vesicles with thrombogenic and immunomodulatory properties. We determined MP subgroups from resting platelets, activated platelets and endothelial cells in donors and apheresis platelet concentrates (PC). MP were double stained with annexin V and CD61 (platelet-derived MP; PMP), P-selectin or CD63 (MP from activated platelets) and CD144 plus E-selectin (endothelial cell-derived MP; EMP) and detected by flow cytometry in platelet donors (n=36) and apheresis PC (n=11; Trima™). PC contained MP, mainly from resting platelets [93% (90-95)], and minor fractions of PMP from activated platelets [P-selectin(+) or CD63(+); 4·8% (3·2-7·7) and 2·6% (2·0-4·0)]. Compared to donors, levels of annexin V+ MP, PMP, P-selectin(+) and CD63(+) MP were 1·7-, 2·3-, 8·6- and 3·1-fold higher in PC (all P<0·05). During storage (1-5 days), levels of annexin V+ MP and PMP did not increase, although small increases in the fraction of P-selectin(+) or CD63(+) MP occurred (both P<0·05). PC also contained EMP, which were 2·6- to 3·7-fold enriched in PC compared to donors (P<0·05). Transfusion of apheresis PC also results in transfusion of HLA-carrying PMP and EMP. This might counteract the aim of reducing transfused HLA load by leucodepletion. The increases in PMP exposing P-selectin or CD63 reflect mild platelet activation during storage. We conclude that in leucodepleted platelet apheresis using fluidized particle bed technology, MP are harvested mainly from the donor by apheresis. Improvement in apheresis technology might reduce MP load. © 2010 The Author(s). Vox Sanguinis © 2010 International Society of Blood Transfusion.

  3. Role of Tumor Suppressor P53 in Megakaryopoiesis and Platelet Function

    Science.gov (United States)

    Apostolidis, Pani A.; Woulfe, Donna S.; Chavez, Massiel; Miller, William M.; Papoutsakis, Eleftherios T.

    2011-01-01

    The pathobiological role of p53 has been widely studied, however its role in normophysiology is relatively unexplored. We previously showed that p53 knock-down increased ploidy in megakaryocytic cultures. This study aims to examine the effect of p53 loss on in vivo megakaryopoiesis, platelet production and function, and to investigate the basis for greater ploidy in p53−/− megakaryocytic cultures. Here, we used flow cytometry to analyze ploidy, DNA synthesis and apoptosis in murine cultured and bone marrow megakaryocytes following thrombopoietin administration and to analyze fibrinogen binding to platelets in vitro. Culture of p53−/− marrow cells for 6 days with thrombopoietin gave rise to 1.7-fold more megakaryocytes, 26.1±3.6% of which reached ploidy classes ≥64N compared to 8.2±0.9% of p53+/+ megakaryocytes. This was due to 30% greater DNA synthesis in p53−/− megakaryocytes and 31% greater apoptosis in p53+/+ megakaryocytes by day 4 of culture. Although the bone marrow and spleen steady-state megakaryocytic content and ploidy were similar in p53+/+ and p53−/− mice, thrombopoietin administration resulted in increased megakaryocytic polyploidization in p53−/− mice. Although their platelet counts were normal, p53−/− mice exhibited significantly longer bleeding times and p53−/− platelets were less sensitive than p53+/+ platelets to agonist-induced fibrinogen binding and P-selectin secretion. In summary, our in vivo and ex-vivo studies indicate that p53 loss leads to increased polyploidization during megakaryopoiesis. Our findings also suggest for the first time a direct link between p53 loss and the development of fully functional platelets resulting in hemostatic deficiencies. PMID:22024107

  4. The kinetics of short-lived Indium-111 radiolabelled platelets

    International Nuclear Information System (INIS)

    Peters, A.M.; Saverymuttu, S.H.; Bell, R.N.; Lavender, J.P.

    1985-01-01

    We have studied the kinetics of autologous 111 In-labelled platelets in patients with reduced platelet life span ( 111 In-labelled platelets in patients with severe thrombocytopenia. Intrasplenic platelet transit time (t) was calculated by compartmental and deconvolution analysis. In patients with a mean platelet life span of less than a few h, compartmental analysis may not be valid and so only deconvolution analysis was applied. There was a close correlation between values of t given by the two approaches (r=0.88, n=18, P<0.001). In some patients with severely reduced mean platelet life span (MPLS), the deconvolved splenic platelet clearance curves appeared to approach an asymptote, the relative magnitude of which was indicative of the irreversible extraction fraction by the spleen of incoming platelets. In othe patients with severely reduced MPLS resulting from abnormal intra-hepatic platelet destruction, the deconvolved splenic curves resembled the normal. The intrasplenic platelet transit time showed no clear relationship with other parameters. It was concluded that platelet pooling within the spleen is normal in patients with reduced platelet life span,including idiopathic thrombocytopenic purpura, even when the predominant site of destruction is the spleen, and that platelets are not delayed in transit through the spleen in preparation of their removal from the circulation and ultimate destruction. (author)

  5. Peptide-Mediated Platelet Capture at Gold Micropore Arrays.

    Science.gov (United States)

    Adamson, Kellie; Spain, Elaine; Prendergast, Una; Moran, Niamh; Forster, Robert J; Keyes, Tia E

    2016-11-30

    Ordered spherical cap gold cavity arrays with 5.4, 1.6, and 0.98 μm diameter apertures were explored as capture surfaces for human blood platelets to investigate the impact of surface geometry and chemical modification on platelet capture efficiency and their potential as platforms for surface enhanced Raman spectroscopy of single platelets. The substrates were chemically modified with single-constituent self-assembled monolayers (SAM) or mixed SAMs comprised of thiol-functionalized arginine-glycine-aspartic acid (RGD, a platelet integrin target) with or without 1-octanethiol (adhesion inhibitor). As expected, platelet adhesion was promoted and inhibited at RGD and alkanethiol modified surfaces, respectively. Platelet adhesion was reversible, and binding efficiency at the peptide modified substrates correlated inversely with pore diameter. Captured platelets underwent morphological change on capture, the extent of which depended on the topology of the underlying substrate. Regioselective capture of the platelets enabled study for the first time of the surface enhanced Raman spectroscopy of single blood platelets, yielding high quality Raman spectroscopy of individual platelets at 1.6 μm diameter pore arrays. Given the medical importance of blood platelets across a range of diseases from cancer to psychiatric illness, such approaches to platelet capture may provide a useful route to Raman spectroscopy for platelet related diagnostics.

  6. Kinetics of short-lived Indium-111 radiolabelled platelets

    Energy Technology Data Exchange (ETDEWEB)

    Peters, A.M.; Saverymuttu, S.H.; Bell, R.N.; Lavender, J.P. (Hammersmith Hospital, London, U.K.)

    1985-01-01

    We have studied the kinetics of autologous /sup 111/In-labelled platelets in patients with reduced platelet life span (<4.5 d), most of whom were thrombocytopenic, and of homologous /sup 111/In-labelled platelets in patients with severe thrombocytopenia. Intrasplenic platelet transit time (t) was calculated by compartmental and deconvolution analysis. In patients with a mean platelet life span of less than a few h, compartmental analysis may not be valid and so only deconvolution analysis was applied. There was a close correlation between values of t given by the two approaches (r=0.88, n=18, P<0.001). In some patients with severely reduced mean platelet life span (MPLS), the deconvolved splenic platelet clearance curves appeared to approach an asymptote, the relative magnitude of which was indicative of the irreversible extraction fraction by the spleen of incoming platelets. In other patients with severely reduced MPLS resulting from abnormal intra-hepatic platelet destruction, the deconvolved splenic curves resembled the normal. The intrasplenic platelet transit time showed no clear relationship with other parameters. It was concluded that platelet pooling within the spleen is normal in patients with reduced platelet life span,including idiopathic thrombocytopenic purpura, even when the predominant site of destruction is the spleen, and that platelets are not delayed in transit through the spleen in preparation of their removal from the circulation and ultimate destruction.

  7. Hypersensitivity to thrombin of platelets from hypercholesterolemic rats

    International Nuclear Information System (INIS)

    Winocour, P.D.; Rand, M.L.; Kinlough-Rathbone, R.L.; Mustard, J.F.

    1986-01-01

    Hypersensitivity of platelets to thrombin has been associated with hypercholesterolemia. The authors have examined the mechanisms involved in this hypersensitivity. Rats were given diets rich in milk fat and containing added cholesterol and taurocholate to produce hypercholesterolemia (HC) (262 +/- 25 mg%) or added sitosterol as a normocholesterolemic control (NC) (89 +/- 6 mg%). Washed platelets were prelabelled with 14 C-serotonin. In the presence of acetylsalicyclic acid (ASA) (to inhibit thromboxane A 2 (TXA 2 ) formation) and creatine phosphate/creatine phosphokinase (CP/CPK) (to remove released ADP), HC platelets aggregated more (26 +/- 1%) and released more 14 C (9.1 +/- 2.0%) than NC platelets (aggregation: 0%, p 14 C release: 1.5 +/- 0.5%, p 2 formation is involved in the hypersensitivity of HC platelets to thrombin. Total binding of 125 I-thrombin to HC platelets was less than that to NC platelets but HC platelets were smaller and had less protein than NC platelets; the thrombin binding per mg platelet protein was the same for HC and NC platelets, indicating that hypersensitivity to thrombin of HC platelets does not result from increased thrombin binding. Thus, hypersensitivity of HC platelets to thrombin is not due to TXA 2 formation, the action of released ADP or increased thrombin binding

  8. Heparin-associated thrombocytopenia: antibody binding specificity to platelet antigens.

    Science.gov (United States)

    Lynch, D M; Howe, S E

    1985-11-01

    Sera from four patients with heparin-associated thrombocytopenia (HAT) were evaluated by a quantitative enzyme-linked immunosorbent assay (ELISA) to detect heparin-dependent serum platelet-bindable immunoglobulin (S-PBIg) and by Western blotting and immunoprecipitation to investigate the specificity of the antibody binding. All HAT sera showed mildly increased S-PBIg (mean, 7.8 fg per platelet; normal, less than 6.0 fg per platelet) to intact target platelets in the ELISA, which was markedly increased in the presence of heparin (mean, 20.9 fg per platelet). This increase was 20-fold greater than normal control sera, which showed a mean differential increase of only 0.5 fg per platelet. Immunoglobulin binding specificity to platelet antigens was investigated using sodium dodecyl sulfate-polyacrylamide gel electrophoresis of platelet lysate with transfer of the platelet fractions onto nitrocellulose strips (Western blotting) and subsequent immunoassay using HAT and normal sera. In the presence of heparin, the four HAT patients demonstrated increased binding of immunoglobulin to platelet antigens of apparent molecular weights of 180, 124, and 82 kd. Radiolabeled heparin when incubated with HAT sera, normal sera, or albumin blanks bound to platelet proteins of the same apparent molecular weights. These observations are consistent with current hypotheses suggesting that HAT antibody is directed to heparin-platelet complexes or, alternatively, that heparin induces conformational change of antigenic sites on the platelet membrane.

  9. Calidad del plasma rico en plaquetas: estudio de la activación plaquetaria Platelet-rich plasma quality: a study on platelet activation

    Directory of Open Access Journals (Sweden)

    C. Sáez-Torres Barroso

    2007-08-01

    Full Text Available Objetivo. El plasma rico en plaquetas (PRP es utilizado de forma cada vez más frecuente en técnicas quirúrgicas de regeneración tisular. No obstante, el procesamiento de la sangre hasta obtener PRP puede desencadenar la activación prematura de las plaquetas y la pérdida de los factores bioactivos. En este trabajo estudiamos la calidad de los concentrados de plaquetas obtenidos siguiendo la técnica de doble centrifugación en tubo. Método. Se someten 50 ml de sangre a una primera centrifugación a 200g 10 minutos, se recoge el sobrenadante y se centrifuga a 700g 15 minutos. Posteriormente, tras eliminar las 2/3 partes del plasma, se resuspenden las plaquetas y se analiza el grado de enriquecimiento, el estado de activación y la reserva funcional de las plaquetas. Resultados. El enriquecimiento en plaquetas del PRP fue de 364±177% (n=45 respecto de los niveles presentes en sangre total. Mediante el estudio de la expresión de CD62 por citometría de flujo se determinó el porcentaje de plaquetas activadas en las muestras de 8 donantes. Mientras que en la sangre no procesada se detectó un 2,7% de plaquetas activadas, tras la preparación del PRP éste era sólo de 3,6%, aumentando hasta el 16% en el concentrado almacenado toda la noche a 22º C. Tras la estimulación con trombina el porcentaje de plaquetas activadas fue de 96,2%. Conclusión. Este protocolo de preparación de PRP no produce una activación significativa de las plaquetas. La respuesta a la estimulación con trombina de los concentrados indica un buen estado de reserva plaquetaria.Objective. Platelet Rich Plasma (PRP is an autologous preparation currently used in oral and maxillofacial reconstructive surgery. Blood collection and preparation of platelet concentrates may lead to platelet activation and the premature loss of their granular load. In this study, we have analyzed the quality of the PRP obtained from a small volume of whole blood through a double centrifugation

  10. Equid herpesvirus type 1 activates platelets.

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    Tracy Stokol

    Full Text Available Equid herpesvirus type 1 (EHV-1 causes outbreaks of abortion and neurological disease in horses. One of the main causes of these clinical syndromes is thrombosis in placental and spinal cord vessels, however the mechanism for thrombus formation is unknown. Platelets form part of the thrombus and amplify and propagate thrombin generation. Here, we tested the hypothesis that EHV-1 activates platelets. We found that two EHV-1 strains, RacL11 and Ab4 at 0.5 or higher plaque forming unit/cell, activate platelets within 10 minutes, causing α-granule secretion (surface P-selectin expression and platelet microvesiculation (increased small events double positive for CD41 and Annexin V. Microvesiculation was more pronounced with the RacL11 strain. Virus-induced P-selectin expression required plasma and 1.0 mM exogenous calcium. P-selectin expression was abolished and microvesiculation was significantly reduced in factor VII- or X-deficient human plasma. Both P-selectin expression and microvesiculation were re-established in factor VII-deficient human plasma with added purified human factor VIIa (1 nM. A glycoprotein C-deficient mutant of the Ab4 strain activated platelets as effectively as non-mutated Ab4. P-selectin expression was abolished and microvesiculation was significantly reduced by preincubation of virus with a goat polyclonal anti-rabbit tissue factor antibody. Infectious virus could be retrieved from washed EHV-1-exposed platelets, suggesting a direct platelet-virus interaction. Our results indicate that EHV-1 activates equine platelets and that α-granule secretion is a consequence of virus-associated tissue factor triggering factor X activation and thrombin generation. Microvesiculation was only partly tissue factor and thrombin-dependent, suggesting the virus causes microvesiculation through other mechanisms, potentially through direct binding. These findings suggest that EHV-1-induced platelet activation could contribute to the thrombosis

  11. Decreased mean platelet volume in panic disorder

    Directory of Open Access Journals (Sweden)

    Göğçegöz Gül I

    2014-09-01

    Full Text Available Işil Göğçegöz Gül, Gül Eryilmaz, Eylem Özten, Gökben Hizli Sayar Neuropsychiatry Health, Practice, and Research Center, Uskudar University, Istanbul, Turkey Aim: The relationship between psychological stress and platelet activation has been widely studied. It is well known that platelets may reflect certain biochemical changes that occur in the brain when different mental conditions occur. Platelet 5-hydroxytryptamine (5-HT is also extensively studied in psychiatry. The mean platelet volume (MPV, the accurate measure of platelet size, has been considered a marker and determinant of platelet function. The aim of the present study was to search for any probable difference in the MPV of subjects with panic disorder (PD.Methods: A total of 37 drug-free subjects, aged 18 to 65 years, diagnosed with PD, with or without agoraphobia, according to the Diagnostic and Statistical Manual of Mental Disorders, Fourth edition (DSM-IV criteria and 45 healthy control subjects were included in the study. Platelet count and MPV were measured and recorded for each subject.Results: There were no statistically significant differences between groups in terms of female/male ratio, age, or body mass index between the PD group and control group (P=0.91, P=0.82, and P=0.93, respectively. The MPV was found to be significantly lower in the PD group compared with the control group (8.8±0.9 fL vs 9.2±0.8 fL; P=0.02. All the participants had MPV values in the standard range of 6.9–10.8 fL.Conclusion: We concluded that abnormalities of the 5-HT1A receptor function in the central nervous system of subjects with a diagnosis of PD are also mirrored in as an alteration in platelet activity. Measurements of platelet activity may be used as a tool for neuropsychiatric and psychopharmacological research and for studying how certain mental diseases and medications affect the central nervous system. Keywords: 5-HT, thrombocyte, anxiety 

  12. Platelet Lysate: The Better Choice for Jaw Periosteal Cell Mineralization

    Directory of Open Access Journals (Sweden)

    Yvonne Wanner

    2017-01-01

    Full Text Available Previously, we demonstrated a high quality of minerals formed by serum-free cultured jaw periosteal cells (JPCs by Raman spectroscopy but the mineralization extent was not satisfactory. In the present study, we analyzed the proliferation and mineralization potential of human platelet lysate- (hPL- cultured JPCs in comparison to that of FCS-cultured JPCs. By cell impedance measurements, we detected significantly higher population doubling times of PL-cultured JPCs in comparison to FCS-cultured JPCs. However, this result was not based on lower proliferation activities but on diminished cell sizes which JPCs develop under PL cultivation. The measurements of the metabolic activities clearly showed significantly higher cell proliferation rates under PL culturing. Equivalent levels of the mesenchymal cell markers CD29, CD45, CD73, CD90, and CD105 were detected, but there were significantly increased MSCA-1 levels under PL cultivation. While JPCs only occasionally mineralize under FCS culture conditions, the mineralization potential was significantly stronger under PL cultivation. Moreover, in 4 of 5 analyzed patient cells, the addition of dexamethasone was proved no longer necessary for strong mineralization of PL-cultured JPCs. We conclude that in vitro cultivation of JPCs with platelet lysate is a suitable alternative to FCS culture conditions and a powerful tool for the development of high-quality TE constructs using jaw periosteal cells.

  13. Platelet Lysate: The Better Choice for Jaw Periosteal Cell Mineralization.

    Science.gov (United States)

    Wanner, Yvonne; Umrath, Felix; Waidmann, Marc; Reinert, Siegmar; Alexander, Dorothea

    2017-01-01

    Previously, we demonstrated a high quality of minerals formed by serum-free cultured jaw periosteal cells (JPCs) by Raman spectroscopy but the mineralization extent was not satisfactory. In the present study, we analyzed the proliferation and mineralization potential of human platelet lysate- (hPL-) cultured JPCs in comparison to that of FCS-cultured JPCs. By cell impedance measurements, we detected significantly higher population doubling times of PL-cultured JPCs in comparison to FCS-cultured JPCs. However, this result was not based on lower proliferation activities but on diminished cell sizes which JPCs develop under PL cultivation. The measurements of the metabolic activities clearly showed significantly higher cell proliferation rates under PL culturing. Equivalent levels of the mesenchymal cell markers CD29, CD45, CD73, CD90, and CD105 were detected, but there were significantly increased MSCA-1 levels under PL cultivation. While JPCs only occasionally mineralize under FCS culture conditions, the mineralization potential was significantly stronger under PL cultivation. Moreover, in 4 of 5 analyzed patient cells, the addition of dexamethasone was proved no longer necessary for strong mineralization of PL-cultured JPCs. We conclude that in vitro cultivation of JPCs with platelet lysate is a suitable alternative to FCS culture conditions and a powerful tool for the development of high-quality TE constructs using jaw periosteal cells.

  14. Platelet transfusions reduce fibrinolysis but do not restore platelet function during trauma hemorrhage.

    Science.gov (United States)

    Vulliamy, Paul; Gillespie, Scarlett; Gall, Lewis S; Green, Laura; Brohi, Karim; Davenport, Ross A

    2017-09-01

    Platelets play a critical role in hemostasis with aberrant function implicated in trauma-induced coagulopathy. However, the impact of massive transfusion protocols on platelet function during trauma hemorrhage is unknown. The aim of this study was to characterize the effects of platelet transfusion on platelet aggregation and fibrinolytic markers during hemostatic resuscitation. Trauma patients enrolled into the prospective Activation of Coagulation and Inflammation in Trauma study between January 2008 and November 2015 who received at least four units of packed red blood cells (PRBCs) were included. Blood was drawn in the emergency department within 2 hours of injury and at intervals after every four units of PRBCs transfused. Platelet aggregation was assessed in whole blood with multiple electrode aggregometry. Plasma proteins were quantified by enzyme-linked immunosorbent assay. Of 161 patients who received four or more PRBCs as part of their initial resuscitation, 44 received 8 to 11 units and 28 received 12 units or more. At each timepoint during bleeding, platelet aggregation was similar in patients who had received a platelet transfusion compared with those who had only received other blood products (p > 0.05 for all timepoints). Platelet transfusion during the four PRBC intervals was associated with a decrease in maximum lysis on rotational thromboelastometry (start of interval, 6% [2-12] vs. end of interval, 2% [0-5]; p = 0.001), an increase in plasminogen activator inhibitor-1 (start of interval, 35.9 ± 14.9 vs. end of interval, 66.7 ± 22.0; p = 0.007) and a decrease in tissue plasminogen activator (start of interval, 26.2 ± 10.5 vs. end of interval, 19.0 +/- 5.1; p = 0.04). No statistically significant changes in these parameters occurred in intervals which did not contain platelets. Current hemostatic resuscitation strategies do not appear to restore platelet aggregation during active hemorrhage. However, stored platelets may attenuate fibrinolysis

  15. Potential fluid mechanic pathways of platelet activation.

    Science.gov (United States)

    Shadden, Shawn C; Hendabadi, Sahar

    2013-06-01

    Platelet activation is a precursor for blood clotting, which plays leading roles in many vascular complications and causes of death. Platelets can be activated by chemical or mechanical stimuli. Mechanically, platelet activation has been shown to be a function of elevated shear stress and exposure time. These contributions can be combined by considering the cumulative stress or strain on a platelet as it is transported. Here, we develop a framework for computing a hemodynamic-based activation potential that is derived from a Lagrangian integral of strain rate magnitude. We demonstrate that such a measure is generally maximized along, and near to, distinguished material surfaces in the flow. The connections between activation potential and these structures are illustrated through stenotic flow computations. We uncover two distinct structures that may explain observed thrombus formation at the apex and downstream of stenoses. More broadly, these findings suggest fundamental relationships may exist between potential fluid mechanic pathways for mechanical platelet activation and the mechanisms governing their transport.

  16. Platelet transfusions can induce transplantation tolerance

    International Nuclear Information System (INIS)

    Claas, F.H.J.; Blankert, J.J.; Ruigrok, R.; Moerel, L.

    1982-01-01

    Recently it was shown that the induction of antibodies against the H-2 antigens after multiple platelet transfusions is due to leukocyte contamination of the platelet suspensions. Pure platelets are not able to induce a primary antibody response. The present study shows that the platelets, however, can be recognized by the immune system but they induce a suppression of the response. Mice pretreated with donor platelets will not give a primary antibody response upon a subsequent injection of donor leukocytes and the survival of donor skin grafts will be prolonged. Similar results were obtained by pretreatment of the responder mice with heat-treated donor leukocytes. Furthermore, repeated injections of heat-treated leukocytes of the recipient strain to the donor before bone marrow grafting, will graft-versus-host mortality. The recipient mice were irradiated and received spleen cell injections. These data show that cells which have only class I antigens on their surface and no activating class II antigens, induce a suppression of the response against class I antigens. (Auth.)

  17. Lea blood group antigen on human platelets

    International Nuclear Information System (INIS)

    Dunstan, R.A.; Simpson, M.B.; Rosse, W.F.

    1985-01-01

    One- and two-stage radioligand assays were used to determine if human platelets possess the Lea antigen. Goat IgG anti-Lea antibody was purified by multiple adsorptions with Le(a-b-) human red blood cells, followed by affinity chromatography with synthetic Lea substance and labeling with 125 I. Human IgG anti-Lea antibody was used either in a two stage radioassay with 125 I-labeled mouse monoclonal IgG anti-human IgG as the second antibody or, alternatively, purified by Staph protein A chromatography, labeled with 125 I, and used in a one-stage radioassay. Platelets from donors of appropriate red blood cell phenotypes were incubated with the antisera, centrifuged through phthalate esters, and assayed in a gamma scintillation counter. Dose response and saturation curve analysis demonstrate the presence of Lewis a antigen on platelets from Lea+ donors. Furthermore, platelets from an Le(a-b-) donor incubated in Le (a+b-) plasma adsorb Lea antigen in a similar manner to red blood cells. The clinical significance of these antigens in platelet transfusion remains undefined

  18. Lymphocyte-platelet crosstalk in Graves' disease.

    Science.gov (United States)

    Kuznik, Boris I; Vitkovsky, Yuri A; Gvozdeva, Olga V; Solpov, Alexey V; Magen, Eli

    2014-03-01

    Platelets can modulate lymphocytes' role in the pathophysiology of thyroid autoimmune diseases. The present study was performed to clarify the status of platelet-lymphocyte subpopulations aggregation in circulating blood in patients with Graves' disease (GD). One hundred and fifty patients with GD (GD group) and 45 hyperthyroid patients with toxic multinodular goiter (TMG group) were recruited in the study. Control group consisted 150 healthy subjects. Immunophenotyping of lymphocytes was performed by flow cytometry. Detection of lymphocyte-platelet aggregates (LPAs) was done using light microscope after Ficoll-gradient centrifugation. The group of GD patients exhibited reduced CD8 lymphocyte and higher CD19 cell counts compared with TMG group and healthy controls. A greater number of activated CD3, HLA-DR+ lymphocytes were observed in GD than in TMG group and control group. GD group was characterized by lower blood platelet count (232 ± 89 × 10 cells/µL) than TMG group (251 ± 97 × 10 cells/µL; P TMG group (116 ± 67/µL, P < 0.005) and control group (104 ± 58 /µL; P < 0.001). GD is associated with higher levels of activated lymphocytes and lymphocyte-platelet aggregates.

  19. Polyphosphate nanoparticles on the platelet surface trigger contact system activation

    NARCIS (Netherlands)

    Verhoef, Johan J F; Barendrecht, Arjan D; Nickel, Katrin F; Dijkxhoorn, Kim; Kenne, Ellinor; Labberton, Linda; McCarty, Owen J T; Schiffelers, Raymond; Heijnen, Harry F G; Hendrickx, Antoni P A; Schellekens, Huub; Fens, Marcel H; de Maat, Steven; Renné, Thomas; Maas, Coen

    2017-01-01

    Polyphosphate is an inorganic polymer that can potentiate several interactions in the blood coagulation system. Blood platelets contain polyphosphate, and the secretion of platelet-derived polyphosphate has been associated with increased thrombus formation and activation of coagulation factor XII.

  20. The content of bone morphogenetic proteins in platelets varies greatly between different platelet donors

    International Nuclear Information System (INIS)

    Kalen, Anders; Wahlstroem, Ola; Linder, Cecilia Halling; Magnusson, Per

    2008-01-01

    Platelet derivates and platelet rich plasma have been used to stimulate bone formation and wound healing because of the rich content of potent growth factors. However, not all reports have been conclusive since some have not been able to demonstrate a positive effect. We investigated the interindividual variation of bone morphogenetic proteins (BMPs) in platelets from healthy donors, and the pH-dependent effect on the release of BMPs in preparations of lysed platelets in buffer (LPB). Platelet concentrates from 31 healthy donors were prepared in pH 4.3 and pH 7.4 buffers and investigated with respect to BMP-2, -4, -6, and -7. BMP-2 and BMP-4 were significantly more common in acidic LPBs in comparison with neutral preparations. We also observed a considerable variation among platelet donors with respect to the release of BMPs at pH 4.3 and 7.4. In conclusion, a considerable variation was found among platelet donors, which may be of importance considering the ambiguous results previously reported on osteoblast proliferation and differentiation

  1. Platelet-activating factor increases platelet-dependent glycoconjugate secretion from tracheal submucosal gland

    International Nuclear Information System (INIS)

    Sasaki, T.; Shimura, S.; Ikeda, K.; Sasaki, H.; Takishima, T.

    1989-01-01

    Using isolated glands from feline trachea, we examined the effect of platelet-activating factor (PAF) on radiolabeled glycoconjugate release and glandular contraction by measuring induced tension in the absence or presence of platelets. PAF alone did not produce any significant glandular contraction nor any significant change in glycoconjugate release from isolated glands. In the presence of purified platelets containing no plasma, PAF (10(-8) to 10(-5) M) produced significant glycoconjugate secretion in a dose-dependent fashion, but it produced no significant glandular contraction. PAF-evoked glycoconjugate secretion was time dependent, reaching a peak response of 277% of control 15-30 min after the exposure of isolated glands to 10(-5) M PAF in the presence of platelets and returning to 135% of controls at 2 h. Platelets alone did not produce any significant stimulation in glycoconjugate release. CV-3988, a known PAF antagonist, inhibited the secretory response to PAF. Methysergide, a known antagonist to receptors for 5-hydroxytryptamine, did not alter PAF-evoked glycoconjugate secretion. Both indomethacin and SQ 29,548, a thromboxane receptor antagonist, abolished the PAF-evoked glycoconjugate secretion from isolated submucosal glands. Epithiomethanothromboxane A2, a stable thromboxane A2 analogue, produced a significant increase in glycoconjugate secretion in a dose-dependent fashion. These findings indicate that PAF increases glycoconjugate release in the presence of platelets and that the increase is dependent on some aspect of platelet function, namely thromboxane generation

  2. Xanthohumol, a Prenylated Flavonoid from Hops (Humulus lupulus, Prevents Platelet Activation in Human Platelets

    Directory of Open Access Journals (Sweden)

    Ye-Ming Lee

    2012-01-01

    Full Text Available Xanthohumol is the principal prenylated flavonoid in the hop plant (Humulus lupulus L.. Xanthohumol was found to be a very potent cancer chemopreventive agent through regulation of diverse mechanisms. However, no data are available concerning the effects of xanthohumol on platelet activation. The aim of this paper was to examine the antiplatelet effect of xanthohumol in washed human platelets. In the present paper, xanthohumol exhibited more-potent activity in inhibiting platelet aggregation stimulated by collagen. Xanthohumol inhibited platelet activation accompanied by relative [Ca2+]i mobilization, thromboxane A2 formation, hydroxyl radical (OH● formation, and phospholipase C (PLCγ2, protein kinase C (PKC, mitogen-activated protein kinase (MAPK, and Akt phosphorylation. Neither SQ22536, an inhibitor of adenylate cyclase, nor ODQ, an inhibitor of guanylate cyclase, reversed the xanthohumol-mediated inhibitory effect on platelet aggregation. Furthermore, xanthohumol did not significantly increase nitrate formation in platelets. This study demonstrates for the first time that xanthohumol possesses potent antiplatelet activity which may initially inhibit the PI3-kinase/Akt, p38 MAPK, and PLCγ2-PKC cascades, followed by inhibition of the thromboxane A2 formation, thereby leading to inhibition of [Ca2+]i and finally inhibition of platelet aggregation. Therefore, this novel role of xanthohumol may represent a high therapeutic potential for treatment or prevention of cardiovascular diseases.

  3. [Assessment study on a set of platelet-rich plasma preparation].

    Science.gov (United States)

    Li, Ming; Zhang, Changqing; Yuan, Ting; Chen, Shengbao; Lü, Ruju

    2011-01-01

    To calculate the recovery rate and enrichment factor and to analyse the correlation by measuring the concentrations of platelets, leukocyte, and growth factors in platelet-rich plasma (PRP) so as to evaluate the feasibility and stability of a set of PRP preparation. The peripheral blood (40 mL) was collected from 30 volunteers accorded with the inclusion criteria, and then 4 mL PRP was prepared using the package produced by Shandong Weigao Group Medical Polymer Company Limited. Automatic hematology analyzer was used to count the concentrations of platelets and leukocyte in whole blood and PRP. The enrichment factor and recovery rate of platelets or leukocyte were calculated; the platelet and leukocyte concentrations of male and female volunteers were measured, respectively. The concentrations of platelet-derived growth factor (PDGF), transforming growth factor beta (TGF-beta), and vascular endothelial growth factor (VEGF) were assayed by ELISA. The platelet concentrations of whole blood and PRP were (131.40 +/- 29.44) x 10(9)/L and (819.47 +/- 136.32) x 10(9)/L, respectively, showing significant difference (t = 27.020, P = 0.000). The recovery rate of platelets was 60.85% +/- 8.97%, and the enrichment factor was 6.40 +/- 1.06. The leukocyte concentrations of whole blood and PRP were (5.57 +/- 1.91) x 10(12)/L and (32.20 +/- 10.42) x 10(12)/L, respectively, showing significant difference (t = 13.780, P = 0.000). The recovery rate of leukocyte was 58.30% +/- 19.24%, and the enrichment factor was 6.10 +/- 1.93. The concentrations of platelets and leukocyte in PRP were positively correlated with the platelet concentration (r = 0.652, P = 0.000) and leukocyte concentration (r = 0.460, P = 0.011) in whole blood. The concentrations of platelet and leukocyte in PRP between male and female were not significantly different (P > 0.05). The concentrations of PDGF, TGF-beta, and VEGF in PRP were (698.15 +/- 64.48), (681.36 +/- 65.90), and (1071.55 +/- 106.04) ng/mL, which were

  4. The binding of fibrinogen to platelets in diabetes mellitus

    International Nuclear Information System (INIS)

    Minno, G. di; Cerbone, A.M.; Iride, C.; Mancini, M.

    1986-01-01

    Platelets from diabetics are known to be more sensitive in vitro to a variety of aggregating agents, to produce more prostaglandin endoperoxides and thromboxane and to bind more 125 I-fibrinogen than platelets from normal controls. Fibrinogen binding to platelets is a pre-requisite for platelet aggregation. Previous studies suggested a role for prostaglandins and/or thrombaxane A 2 in the exposure of fibrinogen receptors on platelets. The present study compares fibrinogen binding to hyperaggregable platelets from diabetic patients and to normal platelets when prostaglandin/thromboxane formation is suppressed by aspirin. It was found that pre-treatment with aspirin reduced collagen or thrombin-induced binding to platelets from none-retinopathic diabetics to the values seen in controls. By contrast, aspirin did not normalize binding to platelets obtained from retinopathic diabetics. The combination of aspirin with apyrase (an ADP scavenger) almost completely inhibited binding and aggregation of platelets from normal controls or non-retinophatic diabetics exposed to collagen or thrombin, whereas it only partially affected binding and aggregation of platelets from retinopathics. By using a monoclonal antibody (B59.2) to the platelet receptor for fibrinogen, we determined that this receptor was quantitatively and qualitatively the same on platelets from normal controls and diabetics. We conclude that increased fibrinogen binding and hyperaggregability of platelets from none-retinopathic diabetics is related to their capacity to form more prostaglandin endoperoxides/thromboxane than normal platelets. In contrast, hyperaggregability and increased binding of platelets from retinopathics appear at least partly related to a mechanism independent of ADP release and thromboxane synthesis. (Author)

  5. Extended Storage of Pathogen Reduced Platelet Concentrates (PRECON)

    Science.gov (United States)

    2015-10-01

    PROCEDURES Protocol, Cold Apheresis Platelets in Isoplate (CAPI) 09/14/15 5 W81XWH-13-2-0089 Page 23 Screening An abbreviated version of blood donor ...2 mL sample for a complete blood count (CBC) to obtain the hematocrit and platelet count. Only criteria aimed at assuring donor safety will apply...platelets will be infused back into the subject. During each platelet infusion, the subject will be carefully monitored for adverse reactions ; i.e

  6. Calcium-binding proteins from human platelets

    International Nuclear Information System (INIS)

    Gogstad, G.O.; Krutnes, M.B.; Solum, N.O.

    1983-01-01

    Calcium-binding platelet proteins were examined by crossed immunoelectrophoresis of solubilized platelets against antibodies to whole platelets followed by incubation of the immunoplates with 45 Ca 2 + and autoradiography. When the immunoplates had been pretreated with EDTA at pH 9.0 in order to remove divalent cations, three immunoprecipitates were markedly labelled with 45 Ca 2 + . These corresponded to the glycoprotein IIb-IIIa complex, glycoprotein Ia and a presently unidentified antigen termed G18. These antigens were membrane-bound and surface-oriented. When an excess of EDTA was introduced in the incubation media the results revealed that the glycoprotein IIb-IIIa complex and antigen G18, but not glycoprotein Ia, contained sites with a stronger affinity for calcium than has EDTA at pH 7.4 Immunoprecipitates of the separate glycoproteins IIb and IIIa both bound calcium in the same manner as the glycoprotein IIb-IIIa complex. As another approach, platelet-rich plasma was incubated with 45 Ca 2 + prior to crossed immunoelectrophoresis of the solubilized platelets. A single immunoprecipitate was wekly labelled. This did not correspond to any of the immunoprecipitates which were visible after staining with Coomassie blue. The labelling of this antigen was markedly increased when the platelt-rich plasma had been preincubated with EDTA and in this case a weak labelling of the glycoprotein IIB-IIIa precipitate also became apparent. No increased incorporation of calcium occured in any of these immunoprecipitates when the platelets were aggregated with ADP in the presence of 45 Ca 2 + . (orig.)

  7. A Novel Platelet Concentrate: Titanium-Prepared Platelet-Rich Fibrin

    OpenAIRE

    Mustafa Tunalı; Hakan Özdemir; Zafer Küçükodacı; Serhan Akman; Emre Yaprak; Hülya Toker; Erhan Fıratlı

    2014-01-01

    We developed a new product called titanium-prepared platelet-rich fibrin (T-PRF). The T-PRF method is based on the hypothesis that titanium may be more effective in activating platelets than the silica activators used with glass tubes in Chouckroun's leukocyte- and platelet-rich fibrin (L-PRF) method. In this study, we aimed to define the structural characteristics of T-PRF and compare it with L-PRF. Blood samples were collected from 10 healthy male volunteers. The blood samples were drawn us...

  8. Determination of reference ranges for immature platelet and reticulocyte fractions and reticulocyte hemoglobin equivalent

    Directory of Open Access Journals (Sweden)

    Iuri Vicente Camargo Morkis

    Full Text Available ABSTRACT Introduction: The immature platelet and immature reticulocyte fractions represent the ratios of platelets and reticulocytes recently released into the circulation and thus with higher RNA content. They are considered early indicators of bone marrow recovery. Objective: The aim of this study was to determine the reference ranges for the immature platelet and reticulocyte fractions of hematologically normal individuals in a university hospital. Methods: Venous blood samples collected in ethylenediaminetetraacetic acid K3 were analyzed using a Sysmex XE-5000™ analyzer. Individuals with platelet and reticulocyte counts within the reference ranges, and a blood count within the laboratory's screening criteria were included. Individuals with clinical conditions that could affect hematological results were excluded. The immature platelet fraction, high, medium and low fluorescence reticulocyte fractions and reticulocyte hemoglobin equivalent were evaluated. The reference ranges were determined according to the recommendations of the International Federation of Clinical Chemistry. Results: One hundred and thirty-two outpatients were evaluated. The mean age was 44 years (range: 13-80 years, 72 (54.5% were women treated in a university hospital. The mean platelet count was 250.8 × 109/L and the mean reticulocyte count was 0.052 × 109/L. The following reference ranges were obtained: immature reticulocyte fraction 1.6-12.1%, the high, medium and low fluorescence reticulocyte fractions were 0.0-1.7%, 1.6-11.0% and 87.9-98.4%, respectively, the reticulocyte hemoglobin equivalent was 30.0-37.6% and immature platelet fraction was 0.8-5.6%. There was a statistically significant difference (p-value = 0.006 between genders in respect to the immature platelet fraction with 0.8-4.7% for females and 0.7-6.1% for males. The immature reticulocyte fraction was directly correlated with the reticulocyte count. Conclusion: Determining the reference range is

  9. The relationship between fractional flow reserve, platelet reactivity and platelet leukocyte complexes in stable coronary artery disease

    NARCIS (Netherlands)

    Sels, J.W.E.M.; Rutten, B.; Holten, van T.C.; Hillaert, M.A.K.; Waltenberger, J.; Pijls, N.H.J.; Pasterkamp, G.; Groot, de P.G.; Roest, M.

    2013-01-01

    Background: The presence of stenoses that significantly impair blood flow and cause myocardial ischemia negatively affects prognosis of patients with stable coronary artery disease. Altered platelet reactivity has been associated with impaired prognosis of stable coronary artery disease. Platelets

  10. MEAN PLATELET VOLUME AND RISK OF THROMBOTIC STROKE

    Directory of Open Access Journals (Sweden)

    Prasantha Kumar Thankappan

    2017-07-01

    Full Text Available BACKGROUND Stroke is a major cause of long term morbidity and mortality. Several factors are known to increase the liability to stroke. Platelets play a crucial role in the pathogenesis of atherosclerotic complications, contributing to thrombus formation. Platelet size (mean platelet volume, MPV is a marker and possible determinant of platelet function, large platelets being potentially more reactive. Hence an attempt has-been made to study the association if any between mean platelet volume and thrombotic stroke. The aim of this study was to determine whether an association exists between Mean Platelet Volume (MPV and thrombotic stroke. MATERIALS AND METHODS The study is a case control study and data was collected at Government Medical College Hospital, Kottayam, Kerala a tertiary care referral centre. The study was carried out among fifty patients diagnosed with thrombotic stroke and presenting to the hospital within forty eight hours of onset of symptoms. Fifty age group and sex matched controls were also recruited. Mean platelet volume was obtained using a SYSMEX automated analyser. RESULTS This study has shown a statistically significant relation between mean platelet volume and risk of thrombotic stroke but no statistically significant correlation between clinical severity of stroke and mean platelet volume. CONCLUSION This study has shown an elevation of MPV in acute phase of thrombotic stroke. Platelet mass was found to be more or less a constant. This study did not find a statistically significant correlation between clinical severity of stroke and mean platelet volume.

  11. Platelet function and HIV: a case-control study.

    LENUS (Irish Health Repository)

    Satchell, Claudette S

    2010-03-13

    Cardiovascular disease and myocardial infarction are of increasing concern in HIV-infected populations. Although platelets mediate arterial thrombosis, central to myocardial infarction, data on platelet function in HIV infection are lacking. We hypothesized that HIV-infected patients would have altered platelet reactivity.

  12. Glycoprotein Ibalpha signalling in platelet apoptosis and clearance

    NARCIS (Netherlands)

    van der Wal, E.

    2010-01-01

    Storage of platelets at low temperature reduces bacterial growth and might better preserve the haemostatic function of platelets than current procedures. Incubation at 0C is known to expose ?-N-acetyl-D-glucosamine-residues on glycoprotein (GP)Ibalpha inducing receptor-clustering and platelet

  13. Glycoprotein Ibα clustering in platelet storage and function

    NARCIS (Netherlands)

    Gitz, E.

    2013-01-01

    Platelets are anucleated, discoid-shaped cells that play an essential role in the formation of a hemostatic plug to prevent blood loss from injured vessels. Initial platelet arrest at the damaged arterial vessel wall is mediated through the interaction between the platelet receptor glycoprotein (GP)

  14. Platelet-vessel wall interaction in health and disease

    NARCIS (Netherlands)

    Löwenberg, E. C.; Meijers, J. C. M.; Levi, M. [=Marcel M.

    2010-01-01

    Upon vessel wall injury platelets rapidly adhere to the exposed subendothelial matrix which is mediated by several cellular receptors present on platelets or endothelial cells and various adhesive proteins such as von Willebrand factor, collagen and fibrinogen. Subsequent platelet activation results

  15. Biochemical and functional abnormalities in hypercholesterolemic rabbit platelets

    International Nuclear Information System (INIS)

    Dalal, K.B.; Ebbe, S.; Mazoyer, E.; Carpenter, D.; Yee, T.

    1990-01-01

    This study was designed to elucidate changes in rabbit platelet lipids induced by a cholesterol rich diet and to explore the possible correlation of these lipid changes with platelet abnormalities. Pronounced biochemical alterations were observed when serum cholesterol levels of 700-1000 mg% were reached. Hypercholesterolemic (HC) platelets contained 37% more neutral lipids and 16% less phospholipids than the controls. Lysolecithin, cholesterol esters and phosphatidylinositol (PI) levels were increased in HC platelets, and the levels of phosphatidylcholine (PC) were decreased. The cholesterol/phospholipid molar ratio of lipidemic platelets increased from 0.55 +/- 0.011 to 0.89 +/- 0.016 (P less than 0.01) in eight weeks. HC platelets had 90% more arachidonic acid (AA) in the PI than normal platelets. No significant changes in AA of PC were observed. Platelet function was monitored by the uptake and release of [14C]serotonin in platelet rich plasma (PRP), using varying concentrations of collagen as an aggregating agent. The uptake of [14C]serotonin in HC and normal platelets ranged from 78-94%. The percent of [14C]serotonin released from normal and HC platelets was proportional to the concentration of collagen. However, lipidemic platelets were hyperreactive to low concentrations of collagen. Incorporation of 50 microM acetylsalicylic acid into the aggregating medium suppressed the release of [14C]serotonin in normal PRP by more than 90%, but had only a partial effect on lipidemic PRP

  16. Letter to editor Platelet volume evaluation in patients with sepsis ...

    African Journals Online (AJOL)

    I have read the article published by Guclu et al. with a great interest.1 They examined platelet indices in patients with sepsis. Mean platelet volume (MPV) and platelet distribution width (PDW) were significantly higher in patients with sepsis than in controls. MPV and PDW were significantly higher in patients with severe ...

  17. The Role of Platelets in Liver Inflammation and Regeneration

    NARCIS (Netherlands)

    Lisman, Ton; Porte, Robert J.

    Platelets play a pivotal role in thrombosis and hemostasis, but an increasing variety of extra-hemostatic functions of platelets are being recognized. This review summarizes recent advances in the understanding of the role of platelets in various pathologies involving the liver. In

  18. Mapuche Herbal Medicine Inhibits Blood Platelet Aggregation

    OpenAIRE

    Falkenberg, Susan Skanderup; Tarnow, Inge; Guzman, Alfonso; Mølgaard, Per; Simonsen, Henrik Toft

    2012-01-01

    12 plant species traditionally used by the Mapuche people in Chile to treat wounds and inflammations have been evaluated for their direct blood platelet inhibition. Seven of the 12 tested plant species showed platelet inhibitory effect in sheep blood, and four of these were also able to inhibit the ADP- (5.0??M) and collagen- (2.0??g/mL) induced aggregations in human blood. These four species in respective extracts (in brackets) were Blechnum chilense (MeOH), Luma apiculata (H2O), Amomyrtus l...

  19. Synergistic effect of signaling from receptors of soluble platelet agonists and outside-in signaling in formation of a stable fibrinogen-integrin αIIbβ3-actin cytoskeleton complex.

    Science.gov (United States)

    Budnik, Ivan; Shenkman, Boris; Savion, Naphtali

    2015-01-01

    Thrombus formation in the injured vessel wall is a highly complex process involving various blood-born components that go through specific temporal and spatial changes as observed by intravital videomicroscopy. Platelets bind transiently to the developing thrombus and may either become stably incorporated into or disengage from the thrombus. The aim of the present study was to reveal the processes involved in the formation of a stable thrombus. Platelet-rich plasma and washed platelets were studied by the aggregometer. The aggregate stability was challenged by eptifibatide. Platelet Triton-insoluble fraction was prepared and the actin and αIIb content in the cytoskeleton was analyzed by western blot. Maximal actin polymerization is achieved 1min after platelet activation while maximal αIIbβ3-actin cytoskeleton association requires 5 to 10min of activation and fibrinogen-mediated platelet-to-platelet bridging. Thus, actin polymerization is dependent on platelet activation and requires neither αIIbβ3 integrin occupation nor platelet aggregation. Formation of a stable aggregate requires platelet activation for more than 1min, complete increase in actin cytoskeleton fraction and partial association of αIIbβ3 with the actin cytoskeleton. However, direct αIIbβ3 activation is not sufficient for cytoskeleton complex formation. Thus, stable αIIbβ3-fibrinogen interaction, representing stable aggregate, is achieved after more than 1min agonist activation, involving inside-out and outside-in signaling but not after direct integrin activation, involving only outside-in signaling. Formation of a stable fibrinogen-αIIbβ3-actin cytoskeleton complex is the result of the combined effect of platelet stimulation by soluble agonists, activation of αIIbβ3, fibrinogen binding and platelet-to-platelet bridging. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. Modeling phase equilibria for acid gas mixtures using the CPA equation of state. Part IV. Applications to mixtures of CO2 with alkanes

    DEFF Research Database (Denmark)

    Tsivintzelis, Ioannis; Ali, Shahid; Kontogeorgis, Georgios

    2015-01-01

    The thermodynamic properties of pure gaseous, liquid or supercritical CO2 and CO2 mixtures with hydrocarbons and other compounds such as water, alcohols, and glycols are very important in many processes in the oil and gas industry. Design of such processes requires use of accurate thermodynamic...... models, capable of predicting the complex phase behavior of multicomponent mixtures as well as their volumetric properties. In this direction, over the last several years, the cubic-plus-association (CPA) thermodynamic model has been successfully used for describing volumetric properties and phase...

  1. Platelet turnover and kinetics in immune thrombocytopenic purpura: results with autologous 111In-labeled platelets and homologous 51Cr-labeled platelets differ

    International Nuclear Information System (INIS)

    Heyns A du, P.; Badenhorst, P.N.; Loetter, M.G.P.; Pieters, H.; Wessels, P.; Kotze, H.F.

    1986-01-01

    Mean platelet survival and turnover were simultaneously determined with autologous 111In-labeled platelets (111In-AP) and homologous 51Cr-labeled platelets (51Cr-HP) in ten patients with chronic immune thrombocytopenic purpura (ITP). In vivo redistribution of the 111In-AP was quantitated with a scintillation camera and computer-assisted image analysis. The patients were divided into two groups: those with splenic platelet sequestration (spleen-liver 111In activity ratio greater than 1.4), and those with diffuse sequestration in the reticuloendothelial system. The latter patients had more severe ITP reflected by pronounced thrombocytopenia, decreased platelet turnover, and prominent early hepatic platelet sequestration. Mean platelet life span estimated with 51Cr-HP was consistently shorter than that of 111In-AP. Platelet turnover determined with 51Cr-HP was thus over-estimated. The difference in results with the two isotope labels was apparently due to greater in vivo elution of 51Cr. Although the limitations of the techniques should be taken into account, these findings indicate that platelet turnover is not always normal or increased in ITP, but is low in severe disease. We suggest that this may be ascribed to damage to megakaryocytes by antiplatelet antibody. The physical characteristics in 111In clearly make this radionuclide superior to 51Cr for the study of platelet kinetics in ITP

  2. Influence of platelet count, platelet mass index, and platelet function on the spontaneous closure of ductus arteriosus in the prematurity

    Directory of Open Access Journals (Sweden)

    Dilek Kahvecioglu

    2018-02-01

    Conclusion: This is the first study in the English literature providing evidence of the influence of platelet dysfunction on the spontaneous closure of ductus arteriosus in prematurity. Longer collagen-ADP duration is identified as a risk factor of ductal closure.

  3. Immunohistochemical Analysis of Platelet Extract Effects on Liver Injury Induced by CCl4 in Male Rats

    Directory of Open Access Journals (Sweden)

    Zahra Hesami

    2016-01-01

    Full Text Available Backgrounds & objectives: Liver damage results in a large accumulation of external cellular matrix that affects the function of this important body organ in a long term and finally stops its function completely. The growth factors existing in platelet extract are more cost-effective, available, and stable than recombinant ones. To determine whether the platelet extract effects on histological changes in liver injury induced by carbon tetrachloride (CCl4, we used immunohistochemical analysis in male rats. Methods: In this project the 28 male Wistar rats (250-300 g were randomly divided into 4 groups, each consisting of 7 animals. The rats were divided into four experimental groups as follows: the first group (sham intraperitoneally received only olive oil as the solvent of carbon tetrachloride; second group (CCl4 intraperitoneally received carbon tetrachloride dissolved in olive oil (ratio of about 1: 1 at a concentration of 1 ml/kg and a twice a week for eight weeks; third group subcutaneously received only platelet extract at a concentration of 0.5 ml/kg twice a week for three weeks; and fourth group received both CCl4 intraperitoneally for eight weeks and platelet extract subcutaneously for last three weeks. After 8 weeks of trial blood and liver sampling were done. Blood samples sent for enzymatic (AST, ALT tests and liver samples tested for histological and immunohistochemical studies. The data were analyzed using  one-way ANOVA followed by Tukey test by Graph pad Prism 5 software and data were considered significant at p≤ 0.05. Results: The results show that platelet extract causes a significant (p≤ 0.001 decrease in liver enzymes and albumin improves the function of liver. The level of alfa smooth muscle actin (α-SMA as an index of hepatic stellate cell activation was decreased by platelet extract administration which eventually reduced the necrosis and fibrosis induced by carbon tetrachloride in studied rats

  4. Efficacy of leukocyte- and platelet-rich fibrin in wound healing: a randomized controlled clinical trial.

    Science.gov (United States)

    Chignon-Sicard, Bérengère; Georgiou, Charalambos A; Fontas, Eric; David, Sylvain; Dumas, Pierre; Ihrai, Tarik; Lebreton, Elisabeth

    2012-12-01

    Application of platelet concentrates to wounds could speed healing. Leukocyte- and platelet-rich fibrin, a relatively recent development, stands out from the other preparations. This prospective, randomized, controlled clinical trial studied the rate of healing of postoperative hand wounds after a single application of leukocyte- and platelet-rich fibrin. Eligible patients were healthy individuals older than 18 years who had been scheduled for elective McCash (open palm) surgery for Dupuytren disease at the Plastic and Hand Surgery Department of Nice's University Hospital between August of 2007 and February of 2010. The control group received the reference care of petroleum jelly mesh (Vaselitulle), and test patients had leukocyte- and platelet-rich fibrin applied. The primary endpoint was healing delay measured in postoperative days. Secondary endpoints included pain, bleeding, and wound exudate. The trial was carried out as a single-blind trial. Among the 68 randomized patients, 33 patients in the leukocyte- and platelet-rich fibrin group and 31 in the Vaselitulle group were analyzed. Primary endpoint analysis showed a median healing delay of 24 days (interquartile range, 18 to 28 days) for the fibrin group and 29 days (interquartile range, 26 to 35 days) for the Vaselitulle group (p = 0.014, log-rank test). Postoperative pain assessment, bleeding, and exudate were always lower for the fibrin group, but not significantly so. The authors trial demonstrates that a single leukocyte- and platelet-rich fibrin application on fresh postoperative hand wounds shows a median improvement of 5 days in comparison with the standard treatment. Therapeutic, II.

  5. Platelet hyperaggregability in obesity: is there a role for nitric oxide impairment and oxidative stress?

    Science.gov (United States)

    Leite, Natália Rodrigues Pereira; Siqueira de Medeiros, Mariana; Mury, Wanda Vianna; Matsuura, Cristiane; Perszel, Monique Bandeira Moss; Noronha Filho, Gerson; Brunini, Tatiana Mc; Mendes-Ribeiro, Antônio Claúdio

    2016-08-01

    Epidemiological evidence has shown that platelet activation markers are consistently elevated in obesity, contributing to its prothrombotic state. In order to improve the understanding of the regulation of platelet function in obesity, the aim of this study was to investigate the l-arginine-nitric oxide (NO) pathway in obese adults without other cardiovascular risk factor. Seventeen obese (body mass index [BMI] 35.9±1.0 kg/m(2) ) and eighteen age-matched normal weight subjects (BMI 22.0±0.6 kg/m(2) ) were included in this study. l-arginine influx was measured with incubation of l-[(3) H]-arginine. NO synthase (NOS) and arginase activities were determined by the citrulline assay and the conversion of l-[(14) C]-arginine to [(14) C]-urea, respectively. Cyclic guanosine monophosphate (cGMP) content was evaluated by enzyme-linked immunosorbent assay. In addition, the study analyzed: platelet aggregation; intraplatelet antioxidant enzymes, via superoxide dismutase (SOD) and catalase activities; and systemic levels of l-arginine, fibrinogen, and C-reactive protein (CRP). Obese patients presented a significant decrease of platelet l-arginine influx, NOS activity, and cGMP levels, along with platelet hyperaggregability. On the presence of NO donor, platelet aggregation was similar between the groups. The fibrinogen and CRP systemic levels were significantly higher and SOD activity was reduced in obesity. No significant differences were observed in plasma levels of l-arginine and intraplatelet arginase and catalase activities between groups. The diminished NO bioavailability associated with inflammatory status and impaired enzymatic antioxidant defence may contribute to future cardiovascular complications in obesity. © 2016 John Wiley & Sons Australia, Ltd.

  6. Quantitative phase imaging of platelets in patients with chronic renal failure treated with hemodialysis

    Science.gov (United States)

    Vasilenko, Irina; Vlasova, Elizaveta; Metelin, Vladislav; Kardasheva, Ziver

    2018-02-01

    The development of robust non-invasive laboratory screening methods for early diagnosis on the out-patient basis seems quite relevant for practical medicine. It is known, that platelet is an original biosensor, a detector of early changes in hemostasis condition. The aim of this study was to assess a potential of the quantitative phase imaging (QPI) technique for real time evaluation the influence of low-molecular weight and unfractionated heparin on platelets in patients with the end-stage of chronic renal failure, who were treated with program hemodialysis (PHD). The main group consisted of 21 patients who were administered a low-molecular weight heparin for hypocoagulation during the procedure of hemodialysis. The control group (15 patients) received unfractionated heparin. Morphodensitometric state of living platelets we evaluated by QPI using computer phase-interference microscope MIM (Moscow, Russia). We analyzed the optical-geometrical parameters and the morphological features of living platelets which reflected the degree of their activation at the beginning of PHD (before administration of heparin), in 15 minutes after it and at the end of the procedure. The results allow us to conclude that the use of low-molecular weight heparin provides better ratio of efficacy/safety and causes a reduction of the platelet activation during the hemodialysis procedure. Practical implementation of QPI for clinical monitoring of platelets makes it possible to obtain important information on hemostasis cell. It opens new opportunities to assess the efficacy of treatment, as well as for early diagnosis of complications for disease.

  7. Evaluation of haematology analyzer CELL-DYN 3700 SL

    Directory of Open Access Journals (Sweden)

    Enver Suljević

    2003-05-01

    Full Text Available Research on the parameters of full blood count and differential white blood count is included in the program of all medical laboratories of primary, secondary and tertiary health care levels. Today, all haematological tests are exclusively performed on the haematology analyzers. Automation of haematology laboratories is a result of the huge requires for haematological test performing, timely issuing of the haematological findings, and possibility of the usage of modern techniques.This work is an evaluation of laser haematology analyzer Cell-Dyn 3700 SL. It investigates the reliability of test results throughout the following parameters: precision, accuracy, sensitivity and specificity of determination methods. It also explores the influence of sample transferring and correlation with haematology analyzer MAXM Retti. Haematology parameters that have been investigated are: white blood cell (WBC, neutrophils (NEU, lymphocytes (LXM, monocytes (MONO, eosinophils (EOS, basophils (BASO, red blood cells (RBC, haemoglobin (HGB, haematocrit (HCT, mean corpuscular volume (MCV, mean corpuscular haemoglobin (MCHC red cell distribution width (RDW, platelet (PLT, mean platelet volume (MPV, plateletocrit (PCT, and platelet distribution width (PDW.The results confirms that precision of analyzer fulfils the reproducibility of testing parameters: WBC, RBC, HGB, MCV, MCH, MCHC, and PLT. Correlation coefficient values (r gained throughout the statistical analysis, that is linear regression results obtained throughout the comparison of two analyzers are adequate except for MCHC (r = 0.64, what is in accordance with literature data.Accuracy is tested by haematology analyzer method and microscopic differentiating method. Correlation coefficient results for granulocytes, lymphocytes and monocytes point the accuracy of methods. Sensitivity and specificity parameters fulfil the analytical criteria.It is confirmed that haematology analyzer Cell-Dyn 3700 SL is reliable for

  8. Radioimmunoassay for platelet activation specific protein GMP-140 on the platelet surface and in plasma

    International Nuclear Information System (INIS)

    Wu Guoxin; Li Jianyong; Ruan Changgeng

    1991-08-01

    Using monoclonal antibody (McAb) SZ-51 which is specific for an alpha-granule membrane protein (GMP-140) on the surface of human activated platelets, the platelet GMP-140 expression in fixed whole blood was measured by direct radioimmunoassay and GMP-140 microparticles in plasma was measured by sandwich method. The GMP-140 molecules per platelet or milliliter (mL) were calculated for the following subjects; acute myocardial infarction; cerebro thrombosis; diabetic mellitus; asthma attack; epidemic hemorrhagic fever etc.. By comparing with the concentration of thromboxane B 2 (TXB 2 ) and von Willebrand factor (vWF) in plasma, it is confirmed that the measurement of GMP-140 molecules is better than that of TXB 2 and vWF. It is a sensitive and specific method for evaluating the platelet activation degree in vivo. The establishment of this method will be useful to diagnosing the thrombotic disorders and studying the pathogenesis of some other diseases

  9. Simple platelet markers: Mean platelet volume and congestive heart failure coexistent with periodontal disease. Pilot studies.

    Science.gov (United States)

    Czerniuk, Maciej R; Bartoszewicz, Zbigniew; Dudzik-Niewiadomska, Iwona; Pilecki, Tomasz; Górska, Renata; Filipiak, Krzysztof J

    2017-07-17

    Conducted pilot study concerning mean platelet volume parameter among patients suffering from congestive heart failure and periodontal disease. Examination of dynamic changes of platelet and periodontal markers in group of 50 patients before and an average of 6 months subsequent to professional periodontal treatment. Both platelet and periodontal parameters decreased after periodontal treatment, what is more, the decrease of mean platelet volume (MPV) value due to periodontal disease/mm improvement was shown to be statistically significant (p = 0.05). Improvement of periodontal status may influence decrease of MPV value andincrease of congestive heart failure treatment efficacy and effect patient comfort. It is a new, not frequently used pattern of chronic disease treatment optimalization.

  10. An Investigation of the Effects of the Mean Platelet Volume, Platelet ...

    African Journals Online (AJOL)

    2018-05-22

    May 22, 2018 ... ratio (PLR), and platelet values for predicting mortality in patients with sepsis. Materials and Methods: This .... Rheumatoid arthritis. Table 2: The .... et al. reported in their study conducted on hemodialysis patients that the PLR ...

  11. Namibia's transition from whole blood-derived pooled platelets to single-donor apheresis platelet collections

    NARCIS (Netherlands)

    Pitman, John P.; Basavaraju, Sridhar V.; Shiraishi, Ray W.; Wilkinson, Robert; von Finckenstein, Bjorn; Lowrance, David W.; Marfin, Anthony A.; Postma, Maarten; Mataranyika, Mary; Smit Sibinga, Cees Th.

    BACKGROUNDFew African countries separate blood donations into components; however, demand for platelets (PLTs) is increasing as regional capacity to treat causes of thrombocytopenia, including chemotherapy, increases. Namibia introduced single-donor apheresis PLT collections in 2007 to increase PLT

  12. Platelet binding and biodistribution of [{sup 99m}Tc]rBitistatin in animal species and humans

    Energy Technology Data Exchange (ETDEWEB)

    Knight, Linda C. [Department of Radiology, Temple University School of Medicine, Philadelphia, PA 19140 (United States)], E-mail: lknight@temple.edu; Romano, Jan E. [Department of Radiology, Temple University School of Medicine, Philadelphia, PA 19140 (United States); Bright, Lewis T.; Agelan, Alexis [University Laboratory Animal Resources, Temple University School of Medicine, Philadelphia, PA 19140 (United States); Kantor, Steven; Maurer, Alan H. [Department of Radiology, Temple University School of Medicine, Philadelphia, PA 19140 (United States)

    2007-10-15

    Introduction: {sup 99m}Tc recombinant bitistatin (rBitistatin) is a radioligand for {alpha}{sub IIb}{beta}{sub 3} (glycoproteins IIb/IIIa) receptor on platelets and is being developed as a diagnostic radiopharmaceutical for in vivo imaging of acute thrombi and emboli. Prior to the first administration of [{sup 99m}Tc]rBitistatin to human subjects, its biodistribution and effects on platelets were evaluated in animals. This paper reports findings in animal studies in comparison with initial findings in normal human subjects. Methods: [{sup 99m}Tc]rBitistatin was administered to mice, guinea pigs and dogs to assess time-dependent organ distribution, urinary excretion and blood disappearance rates. Blood samples were analyzed to determine radioligand binding to circulating platelets and the extent of plasma protein binding. The effect of [{sup 99m}Tc]rBitistatin on circulating platelet count was determined. These factors were also determined in normal human subjects who received [{sup 99m}Tc]rBitistatin as part of a Phase I clinical trial. Results: The main organs that accumulated [{sup 99m}Tc]rBitistatin were kidneys, liver and spleen in all animal species and humans. The main organs seen on human images were the kidneys and spleen. Liver uptake was fainter, and soft-tissue background was low. [{sup 99m}Tc]rBitistatin bound to circulating platelets in blood, with a higher percentage of binding to platelets in guinea pigs and dogs compared to that in humans. Plasma protein binding was low and of little consequence in view of platelet binding. The main route of excretion was through the urine. [{sup 99m}Tc]rBitistatin did not affect platelet counts in humans or dogs. Conclusions: [{sup 99m}Tc]rBitistatin, when administered at low doses for imaging, has no adverse effects on platelets and has the qualitative biodistribution predicted by animal studies. [{sup 99m}Tc]rBitistatin was found to bind to circulating platelets in humans, suggesting that it will be able to bind

  13. The role of platelets in hemostasis and the effects of snake venom toxins on platelet function.

    Science.gov (United States)

    de Queiroz, Mayara Ribeiro; de Sousa, Bruna Barbosa; da Cunha Pereira, Déborah Fernanda; Mamede, Carla Cristine Neves; Matias, Mariana Santos; de Morais, Nadia Cristina Gomes; de Oliveira Costa, Júnia; de Oliveira, Fábio

    2017-07-01

    The human body has a set of physiological processes, known as hemostasis, which keeps the blood fluid and free of clots in normal vessels; in the case of vascular injury, this process induces the local formation of a hemostatic plug, preventing hemorrhage. The hemostatic system in humans presents complex physiological interactions that involve platelets, plasma proteins, endothelial and subendothelial structures. Disequilibrium in the regulatory mechanisms that control the growth and the size of the thrombus is one of the factors that favors the development of diseases related to vascular disorders such as myocardial infarction and stroke, which are among the leading causes of death in the western world. Interfering with platelet function is a strategy for the treatment of thrombotic diseases. Antiplatelet drugs are used mainly in cases related to arterial thrombosis and interfere in the formation of the platelet plug by different mechanisms. Aspirin (acetylsalicylic acid) is the oldest and most widely used antithrombotic drug. Although highly effective in most cases, aspirin has limitations compared to other drugs used in the treatment of homeostatic disorders. For this reason, research related to molecules that interfere with platelet aggregation are of great relevance. In this regard, snake venoms are known to contain a number of molecules that interfere with hemostasis, including platelet function. The mechanisms by which snake venom components inhibit or activate platelet aggregation are varied and can be used as tools for the diagnosis and the treatment of several hemostatic disorders. The aim of this review is to present the role of platelets in hemostasis and the mechanisms by which snake venom toxins interfere with platelet function. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Radiation-induced volatile hydrocarbon production in platelets

    International Nuclear Information System (INIS)

    Radha, E.; Vaishnav, Y.N.; Kumar, K.S.; Weiss, J.F.

    1989-01-01

    Generation of volatile hydrocarbons (ethane, pentane) as a measure of lipid peroxidation was followed in preparations from platelet-rich plasma irradiated in vitro. The hydrocarbons in the headspace of sealed vials containing irradiated and nonirradiated washed platelets, platelet-rich plasma, or platelet-poor plasma increased with time. The major hydrocarbon, pentane, increased linearly and significantly with increasing log radiation dose, suggesting that reactive oxygen species induced by ionizing radiation result in lipid peroxidation. Measurements of lipid peroxidation products may give an indication of suboptimal quality of stored and/or irradiated platelets

  15. Platelet concentrates for transfusion-metabolic and storage aspects.

    Science.gov (United States)

    Farrugia, A

    1994-01-01

    Transfusion of platelets concentrated from donated blood is an established therapeutic modality in clinical medicine. Over the past 25 years much effort has gone into optimising the conditions for the collection, preparation and storage of platelets for transfusion. Despite significant advances, platelet production is still a costly process requiring a dedicated environment and the use of specially formulated plastic storage containers. A progressive lesion over storage limits the shelf life and the availability of donated platelets, while the need to store platelets in the donor's autologous plasma also results in a loss of valuable fresh plasma for fractionation. Recent studies have addressed the issues of platelet quality and plasma economy by examining the possibility of storing platelets in a synthetic medium. Platelets stored in a variety of crystalloid solutions have been shown to retain in vitro and in vivo properties equivalent or superior to platelets stored in autologous donor plasma. Some additional insight has been gained on the metabolic patterns of stored platelets. In particular, studies have shown that, under these conditions, platelets are unable to oxidise dextrose to any significant extent, and that dextrose is invariably broken down to lactate, irrespective of the oxygen tensions in the platelet's environment. This in turn leads to the metabolic lesion of platelet storage, whereby low pH results in loss of platelet viability. Platelets stored in synthetic dextrose-free media are capable of maintaining aerobic ATP generation, and acetate-a component of many media studied-has been shown to be metabolised by platelets. Similarly, platelets prepared from blood collected into a dextrose-free anticoagulant have satisfactory properties both when suspended in autologous plasma or in a dextrose-free synthetic medium. The requirements for storage in special, high gas-permeable, containers, and for constant agitation during storage, were both found to be

  16. Flavonoids and platelet aggregation: A brief review.

    Science.gov (United States)

    Faggio, Caterina; Sureda, Antoni; Morabito, Silvia; Sanches-Silva, Ana; Mocan, Andrei; Nabavi, Seyed Fazel; Nabavi, Seyed Mohammad

    2017-07-15

    Platelets are small anucleated fragments derived from a megakaryocyte precursor. Platelets play a key role in many physiological functions especially in hemostasis and wound healing processes in order to maintain the integrity of the circulatory system. In addition, activated platelets release cytokines and chemokines which modulate the immune response and, in some cases of hyperactivation, they could be associated to the pathogenesis of inflammatory diseases. Flavonoids are polyphenolic compounds ubiquosly found in plants known to be potent antioxidants with positive effects against diverse diseases such as cancer, neurodegenerative or cardiovascular disease. It has been reported that some flavonoids possess anti-platelet aggregation effects though different pathways, being the inhibition of the arachidonic acid-based pathway the most representative mechanism of action. In the present review, the main sources of flavonoids, as well as their bioavailability and metabolism are summarized. Moreover, the available data about the anti-aggregation effects of flavonoids and the different mechanisms of action that has been proposed until now are also discussed. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Sports medicine applications of platelet rich plasma.

    Science.gov (United States)

    Mishra, Allan; Harmon, Kimberly; Woodall, James; Vieira, Amy

    2012-06-01

    Platelet rich plasma (PRP) is a powerful new biologic tool in sports medicine. PRP is a fraction of autologous whole blood containing and increased number of platelets and a wide variety of cytokines such as platelet derived growth factor (PDGF), vascular endothelial growth factor (VEGF) and transforming growth factor beta-1 (TGF-B1), fibroblast growth factor (FGF), Insulin-like growth factor-1 (IGF-1) among many others. Worldwide interest in this biologic technology has recently risen sharply. Basic science and preclinical data support the use of PRP for a variety of sports related injuries and disorders. The published, peer reviewed, human data on PRP is limited. Although the scientific evaluation of clinical efficacy is in the early stages, elite and recreational athletes already use PRP in the treatment of sports related injuries. Many questions remain to be answered regarding the use of PRP including optimal formulation, including of leukocytes, dosage and rehabilitation protocols. In this review, a classification for platelet rich plasma is proposed and the in-vitro, preclinical and human investigations of PRP applications in sports medicine will be reviewed as well as a discussion of rehabilitation after a PRP procedure. The regulation of PRP by the World Anti-Doping Agency will also be discussed. PRP is a promising technology in sports medicine; however, it will require more vigorous study in order to better understand how to apply it most effectively.

  18. Platelet-rich fibrin: the benefits.

    Science.gov (United States)

    Kumar, Yuvika Raj; Mohanty, Sujata; Verma, Mahesh; Kaur, Raunaq Reet; Bhatia, Priyanka; Kumar, Varun Raj; Chaudhary, Zainab

    2016-01-01

    Current published data presents confusing results about the effects of platelet-rich fibrin on bone, and there is a need for studies that throw light on its effect. Our main objective therefore was to evaluate (by fractal analysis) osseous regeneration in extraction sockets with and without platelet-rich fibrin in a study with a substantial sample and a reliable technique to calibrate its effects on bone cells. We also assessed the soft tissue response. Thirty-four patients had their bilaterally impacted third molars (68 surgical sites) extracted in this split-mouth study, following which platelet-rich fibrin was placed in one of the sockets. Patients were followed up clinically and radiographically, and a pain score and fractal analysis were used to evaluate healing of soft tissue and bone, respectively. We conclude that platelet-rich fibrin improves healing of both soft and hard tissues. Although osseous healing did not differ significantly between the groups, healing of soft tissue as judged by the pain score was significantly better in the experimental group. Copyright © 2015 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

  19. BLOOD CHEMISTRY AND PLATELET SEROTONIN UPTAKE AS ...

    African Journals Online (AJOL)

    A cross sectional study was conducted to investigate the blood chemistry and platelet serotonin uptake as alternative method of determining HIV disease stage in HIV/AIDS patients. Whole blood was taken from subjects at the Human Virology of the Nigerian Institute of Medical Research. Subjects were judged suitable for ...

  20. Thermophoresis of Nano Platelets in Confined Space

    Science.gov (United States)

    Hardt, Steffen

    2007-11-01

    For several decades it has been known that a rigid body immersed in a gas of nonuniform temperature experiences a thermophoretic force aligned with the temperature gradient. If however, a body is placed in a narrow gap between two solid walls of uniform, but different temperature, a thermophoretic force perpendicular to the temperature gradient can be created. In this work an analytical expression is derived for the force experienced by a nano platelet between two walls of different temperature. It is assumed that the in-plane extension of the platelet is larger than the gap width and that the gas dynamics occurs in the free-molecular flow regime. For the case that the gas molecules are diffusively reflected from the walls, it can be shown that the wall collision rate is constant over the whole computational domain. Based on this insight, expressions for the force and the torque on a nano platelet in a narrow gap are derived. It is shown that the torque vanishes, whereas there is a net force perpendicular to the temperature gradient. When considering thermal fluctuations on top of the average force it becomes apparent that in such a way a thermophoretic motion of a platelet can be induced.

  1. Comparison of the effect of calcium gluconate and batroxobin on the release of transforming growth factor beta 1 in canine platelet concentrates

    Directory of Open Access Journals (Sweden)

    Silva Raul F

    2012-07-01

    Full Text Available Abstract Background The clinical use of autologous platelet concentrates (also known as platelet-rich plasma on the field of regenerative therapy, in the last decade has been the subject of several studies especially in equine medicine and surgery. The objectives of this study was: 1 to describe and compare the cellular population in whole blood, lower fraction (A and upper fraction (B of platelet concentrates, 2 to measure and compare the transforming growth factor beta 1 (TGF-β1 concentration in plasma and both platelet concentrates after be activated with calcium gluconate or batroxobin plus calcium gluconate and, 3 to determine correlations between cell counts in platelet concentrates and concentrations of TGF-β1. Blood samples were taken from 16 dogs for complete blood count, plasma collection and platelet concentrates preparation. The platelet concentrates (PC were arbitrarily divided into two fractions, specifically, PC-A (lower fraction and PC-B (upper fraction. The Platelet concentrates were analyzed by hemogram. After activated with calcium gluconate or batroxobin plus calcium gluconate, TGF-β1 concentration was determined in supernatants of platelet concentrates and plasma. Results There were differences statistically significant (P 1 concentration between whole blood, plasma and both platelet concentrates. A significant correlation was found between the number of platelets in both platelet concentrates and TGF-β1 concentration. Platelet collection efficiency was 46.34% and 28.16% for PC-A and PC-B, respectively. TGF-β1 concentration efficiency for PC activated with calcium gluconate was 47.75% and 31.77%, for PC-A and PC-B, respectively. PC activated with batroxobin plus CG showed 46.87% and 32.24% for PC-A and PC-B, respectively. Conclusions The methodology used in this study allows the concentration of a number of platelets and TGF-β1 that might be acceptable for a biological effect for clinical or experimental use as a

  2. The Signaling Role of CD40 Ligand in Platelet Biology and in Platelet Component Transfusion

    Science.gov (United States)

    Aoui, Chaker; Prigent, Antoine; Sut, Caroline; Tariket, Sofiane; Hamzeh-Cognasse, Hind; Pozzetto, Bruno; Richard, Yolande; Cognasse, Fabrice; Laradi, Sandrine; Garraud, Olivier

    2014-01-01

    The CD40 ligand (CD40L) is a transmembrane molecule of crucial interest in cell signaling in innate and adaptive immunity. It is expressed by a variety of cells, but mainly by activated T-lymphocytes and platelets. CD40L may be cleaved into a soluble form (sCD40L) that has a cytokine-like activity. Both forms bind to several receptors, including CD40. This interaction is necessary for the antigen specific immune response. Furthermore, CD40L and sCD40L are involved in inflammation and a panoply of immune related and vascular pathologies. Soluble CD40L is primarily produced by platelets after activation, degranulation and cleavage, which may present a problem for transfusion. Soluble CD40L is involved in adverse transfusion events including transfusion related acute lung injury (TRALI). Although platelet storage designed for transfusion occurs in sterile conditions, platelets are activated and release sCD40L without known agonists. Recently, proteomic studies identified signaling pathways activated in platelet concentrates. Soluble CD40L is a good candidate for platelet activation in an auto-amplification loop. In this review, we describe the immunomodulatory role of CD40L in physiological and pathological conditions. We will focus on the main signaling pathways activated by CD40L after binding to its different receptors. PMID:25479079

  3. Platelet indices as markers of platelet turnover and aggregation: pathophysiological interpretation, clinical impact, perspectives in research

    Directory of Open Access Journals (Sweden)

    Malinova L.I.

    2017-12-01

    Full Text Available The purpose of the review is to characterize existing in open access bibliographical databases such as eLibrary and PubMed evidence on clinical impact of morphometric platelet indices as markers of platelet aggregation ability and turnover as a methodology and theoretical framework of further investigation. Studies results were pooled from open access bibliographic databases (eLibrary, and PubMed according to modified PRISMA algorithm. Relevant studies were identified by systematic searches of the original studies published during the last 10 years in the Russian and English languages. Results of 96 original studies in accordance with inclusion criteria were published during the last 10 years in scientific journals indexed in eLibrary, and PubMed. The majority of publications (64.58% consist of evidence pro diagnostic and prognostic significance of platelet indices. Studies demonstrating the significance of platelet indices as possible risk markers of thrombotic events in cardiovascular patients were predominating among "pro" publications. In 15.63% published results contradict concept of platelet indices usefulness as diagnostic and prognostic markers in clinical practice. Morphometric platelet indices can be considered as useful diagnostic and prognostic markers of thrombotic events in cardiovascular patients. Existing gaps in evidence suggest the need of further investigations.

  4. Platelets and the innate immune system: mechanisms of bacterial-induced platelet activation.

    Science.gov (United States)

    Cox, D; Kerrigan, S W; Watson, S P

    2011-06-01

    It has become clear that platelets are not simply cell fragments that plug the leak in a damaged blood vessel; they are, in fact, also key components in the innate immune system, which is supported by the presence of Toll-like receptors (TLRs) on platelets. As the cells that respond first to a site of injury, they are well placed to direct the immune response to deal with any resulting exposure to pathogens. The response is triggered by bacteria binding to platelets, which usually triggers platelet activation and the secretion of antimicrobial peptides. The main platelet receptors that mediate these interactions are glycoprotein (GP)IIb-IIIa, GPIbα, FcγRIIa, complement receptors, and TLRs. This process may involve direct interactions between bacterial proteins and the receptors, or can be mediated by plasma proteins such as fibrinogen, von Willebrand factor, complement, and IgG. Here, we review the variety of interactions between platelets and bacteria, and look at the potential for inhibiting these interactions in diseases such as infective endocarditis and sepsis. © 2011 International Society on Thrombosis and Haemostasis.

  5. The important role of von Willebrand factor in platelet-derived FVIII gene therapy for murine hemophilia A in the presence of inhibitory antibodies.

    Science.gov (United States)

    Shi, Q; Schroeder, J A; Kuether, E L; Montgomery, R R

    2015-07-01

    Our previous studies have demonstrated that targeting FVIII expression to platelets results in FVIII storage together with von Willebrand factor (VWF) in platelet α-granules and that platelet-derived FVIII (2bF8) corrects the murine hemophilia A phenotype even in the presence of high-titer anti-FVIII inhibitory antibodies (inhibitors). To explore how VWF has an impact on platelet gene therapy for hemophilia A with inhibitors. 2bF8 transgenic mice in the FVIII(-/-) background (2bF8(tg+/-) F8(-/-) ) with varying VWF phenotypes were used in this study. Animals were analyzed by VWF ELISA, FVIII activity assay, Bethesda assay and tail clip survival test. Only 18% of 2bF8(tg+/-) F8(-/-) VWF(-/-) animals, in which VWF was deficient, survived the tail clip challenge with inhibitor titers of 3-8000 BU mL(-1) . In contrast, 82% of 2bF8(tg+/-) F8(-/-) VWF(+/+) mice, which had normal VWF levels, survived tail clipping with inhibitor titers of 10-50,000 BU mL(-1) . All 2bF8(tg+/-) F8(-/-) VWF(-/-) mice without inhibitors survived tail clipping and no VWF(-/-) F8(-/-) mice survived this challenge. Because VWF is synthesized by endothelial cells and megakaryocytes and is distributed in both plasma and platelets in peripheral blood, we further investigated the effect of each compartment of VWF on platelet-FVIII gene therapy for hemophilia A with inhibitors. In the presence of inhibitors, 42% of animals survived tail clipping in the group with plasma-VWF and 50% survived in the platelet-VWF group. VWF is essential for platelet gene therapy for hemophilia A with inhibitors. Both platelet-VWF and plasma-VWF are required for optimal platelet-derived FVIII gene therapy for hemophilia A in the presence of inhibitors. © 2015 International Society on Thrombosis and Haemostasis.

  6. Platelet "first responders" in wound response, cancer, and metastasis.

    Science.gov (United States)

    Menter, David G; Kopetz, Scott; Hawk, Ernest; Sood, Anil K; Loree, Jonathan M; Gresele, Paolo; Honn, Kenneth V

    2017-06-01

    Platelets serve as "first responders" during normal wounding and homeostasis. Arising from bone marrow stem cell lineage megakaryocytes, anucleate platelets can influence inflammation and immune regulation. Biophysically, platelets are optimized due to size and discoid morphology to distribute near vessel walls, monitor vascular integrity, and initiate quick responses to vascular lesions. Adhesion receptors linked to a highly reactive filopodia-generating cytoskeleton maximizes their vascular surface contact allowing rapid response capabilities. Functionally, platelets normally initiate rapid clotting, vasoconstriction, inflammation, and wound biology that leads to sterilization, tissue repair, and resolution. Platelets also are among the first to sense, phagocytize, decorate, or react to pathogens in the circulation. These platelet first responder properties are commandeered during chronic inflammation, cancer progression, and metastasis. Leaky or inflammatory reaction blood vessel genesis during carcinogenesis provides opportunities for platelet invasion into tumors. Cancer is thought of as a non-healing or chronic wound that can be actively aided by platelet mitogenic properties to stimulate tumor growth. This growth ultimately outstrips circulatory support leads to angiogenesis and intravasation of tumor cells into the blood stream. Circulating tumor cells reengage additional platelets, which facilitates tumor cell adhesion, arrest and extravasation, and metastasis. This process, along with the hypercoagulable states associated with malignancy, is amplified by IL6 production in tumors that stimulate liver thrombopoietin production and elevates circulating platelet numbers by thrombopoiesis in the bone marrow. These complex interactions and the "first responder" role of platelets during diverse physiologic stresses provide a useful therapeutic target that deserves further exploration.

  7. Platelet fibrinogen binding in Basset Hound Hereditary Thrombopathy

    International Nuclear Information System (INIS)

    Patterson, W.; Estry, D.; Schwartz, K.; Bell, T.

    1986-01-01

    Platelets from dogs with Basset Hound Hereditary Thrombopathy (BHT) display a thrombasthenia-like aggregation defect but have been shown to have normal amounts of platelet membrane glycoproteins IIb and IIIa (GP IIb-IIIa). In order to investigate the possibility of a functionally abnormal GPIIb-IIIa complex, which might be unable to bind fibrinogen after stimulation, fibrinogen binding in BHT was evaluated. Two canine fibrinogen preparations were used, one from BHT dogs and one from normal control dogs, as well as a human fibrinogen preparation. Platelets from BHT and normal dogs were activated with 1 x 10 -5 M ADP in the presence of 125 I-labeled fibrinogen and the surface bound radioactivity quantitated. For all fibrinogen preparations, the amount of fibrinogen bound by BHT platelets was not significantly different than that bound by normal dog platelets. BHT platelets bound 23,972 +/- 3612 and normal dog platelets bound 23,033 +/- 3971 molecules of fibrinogen per platelet. The BHT platelet aggregation defect does not seem to be caused by a functionally abnormal GP IIb-IIIa complex, since BHT platelets bind normal amounts of fibrinogen. The results suggest that fibrinogen binding is not sufficient for platelet aggregation, and other factors, perhaps receptor mobility and membrane phospholipid content should be investigated in BHT

  8. Modified expression of surface glyconjugates in stored human platelets

    International Nuclear Information System (INIS)

    Dhar, A.; Ganguly, P.

    1987-01-01

    Platelets are anucleated cells which play an important part in blood coagulation and thrombosis. These cells may be stored in the blood bank for only 4/5 days. In order to improve the storage of platelets, it is essential to first understand the changes in these cells due to storage. In this work, human platelets were stored in autologous plasma at 4 0 or 22 0 and their surface changes were monitored with three lectins - wheat germ afflutinin (WGA), concanavalin A (Con A) and lentil lectin (LL). Blood was drawn from healthy donors and platelet rich plasma (PRP) was collected by slow speed centrifugation. Platelets stored at either temperature for different times showed increased sensitivity to agglutination by WGA after 34-48 hrs. Lectins, Con A and LL, which were not agglutinating to fresh platelets readily caused agglutination after 48-72 hrs. The platelets stored for 25 hrs or longer period were insensitive to thrombin but showed enhanced aggregation with WGA. Labelling of surface glycoconjugates of stored platelets with 3 H-boro-hydride revealed progressive loss of a glycoprotein of Mr 150,000 (GPIb infinity) together with the appearance of components of Mr 69,000; Mr 60,000; Mr 25,000. New high molecular weight glycoproteins were also detected only in stored platelets. The author studies clearly indicate that modification or altered expression of platelets surface glycoproteins may be one factor of storage related dysfunction of platelets

  9. Modified expression of surface glyconjugates in stored human platelets

    Energy Technology Data Exchange (ETDEWEB)

    Dhar, A.; Ganguly, P.

    1987-05-01

    Platelets are anucleated cells which play an important part in blood coagulation and thrombosis. These cells may be stored in the blood bank for only 4/5 days. In order to improve the storage of platelets, it is essential to first understand the changes in these cells due to storage. In this work, human platelets were stored in autologous plasma at 4/sup 0/ or 22/sup 0/ and their surface changes were monitored with three lectins - wheat germ afflutinin (WGA), concanavalin A (Con A) and lentil lectin (LL). Blood was drawn from healthy donors and platelet rich plasma (PRP) was collected by slow speed centrifugation. Platelets stored at either temperature for different times showed increased sensitivity to agglutination by WGA after 34-48 hrs. Lectins, Con A and LL, which were not agglutinating to fresh platelets readily caused agglutination after 48-72 hrs. The platelets stored for 25 hrs or longer period were insensitive to thrombin but showed enhanced aggregation with WGA. Labelling of surface glycoconjugates of stored platelets with /sup 3/H-boro-hydride revealed progressive loss of a glycoprotein of Mr 150,000 (GPIb infinity) together with the appearance of components of Mr 69,000; Mr 60,000; Mr 25,000. New high molecular weight glycoproteins were also detected only in stored platelets. The author studies clearly indicate that modification or altered expression of platelets surface glycoproteins may be one factor of storage related dysfunction of platelets.

  10. Abnormal megakaryocyte development and platelet function in Nbeal2(-/-) mice.

    Science.gov (United States)

    Kahr, Walter H A; Lo, Richard W; Li, Ling; Pluthero, Fred G; Christensen, Hilary; Ni, Ran; Vaezzadeh, Nima; Hawkins, Cynthia E; Weyrich, Andrew S; Di Paola, Jorge; Landolt-Marticorena, Carolina; Gross, Peter L

    2013-11-07

    Gray platelet syndrome (GPS) is an inherited bleeding disorder associated with macrothrombocytopenia and α-granule-deficient platelets. GPS has been linked to loss of function mutations in NEABL2 (neurobeachin-like 2), and we describe here a murine GPS model, the Nbeal2(-/-) mouse. As in GPS, Nbeal2(-/-) mice exhibit splenomegaly, macrothrombocytopenia, and a deficiency of platelet α-granules and their cargo, including von Willebrand factor (VWF), thrombospondin-1, and platelet factor 4. The platelet α-granule membrane protein P-selectin is expressed at 48% of wild-type levels and externalized upon platelet activation. The presence of P-selectin and normal levels of VPS33B and VPS16B in Nbeal2(-/-) platelets suggests that NBEAL2 acts independently of VPS33B/VPS16B at a later stage of α-granule biogenesis. Impaired Nbeal2(-/-) platelet function was shown by flow cytometry, platelet aggregometry, bleeding assays, and intravital imaging of laser-induced arterial thrombus formation. Microscopic analysis detected marked abnormalities in Nbeal2(-/-) bone marrow megakaryocytes, which when cultured showed delayed maturation, decreased survival, decreased ploidy, and developmental abnormalities, including abnormal extracellular distribution of VWF. Our results confirm that α-granule secretion plays a significant role in platelet function, and they also indicate that abnormal α-granule formation in Nbeal2(-/-) mice has deleterious effects on megakaryocyte survival, development, and platelet production.

  11. Web server attack analyzer

    OpenAIRE

    Mižišin, Michal

    2013-01-01

    Web server attack analyzer - Abstract The goal of this work was to create prototype of analyzer of injection flaws attacks on web server. Proposed solution combines capabilities of web application firewall and web server log analyzer. Analysis is based on configurable signatures defined by regular expressions. This paper begins with summary of web attacks, followed by detection techniques analysis on web servers, description and justification of selected implementation. In the end are charact...

  12. Electron attachment analyzer

    International Nuclear Information System (INIS)

    Popp, P.; Grosse, H.J.; Leonhardt, J.; Mothes, S.; Oppermann, G.

    1984-01-01

    The invention concerns an electron attachment analyzer for detecting traces of electroaffine substances in electronegative gases, especially in air. The analyzer can be used for monitoring working places, e. g., in operating theatres. The analyzer consists of two electrodes inserted in a base frame of insulating material (quartz or ceramics) and a high-temperature resistant radiation source ( 85 Kr, 3 H, or 63 Ni)

  13. An Inherited Platelet Function Defect in Basset Hounds

    Science.gov (United States)

    Johnstone, I. B.; Lotz, F.

    1979-01-01

    An inherited platelet function defect occurring in a family of basset hounds has been described. The trait is transmitted as an autosomal characteristic and appears to be expressed clinically only in the homozygous state. The characteristics of this platelet defect include: 1) marked bleeding tendencies and prolonged skin bleeding times in either male or female dogs. 2) normal blood coagulation mechanism. 3) adequate numbers of circulating platelets which appear morphologically normal by light microscopy. 4) normal whole blood clot retraction. 5) deficient in vivo platelet consumption and in vitro platelet retention in glass bead columns. 6) defective ADP-induced platelet aggregation in homozygotes, apparently normal ADP response in heterozygotes, and defective collagen-induced platelet aggregation in both. PMID:509382

  14. The measurement of platelet activation by radioimmunoassay in asthma

    International Nuclear Information System (INIS)

    Wu Guoxin; Sun Jian; Li Jianyong; Ruan Changgeng

    1992-02-01

    Radioimmunoassay with specific monoclonal antibody was used to evaluate the platelet activation in 14 cases of acute bronchial asthma. The result showed that the number of molecules of alpha-granule membrane protein (GMP-140) which was exposed on the surface of platelet following secretion significantly increased on the surface of platelet and in plasma, while the number of molecules of glycoprotein (GP) I b and GPIII a did not change significantly; the concentration of thromboxane B 2 in plasma was raised, while the concentration of 6-keto-PGF 1a was within the normal limits; the concentrations of β-thromboglobulin (β-TG) and platelet factor 4(PF 4 ) in plasma increased significantly; the number of platelets decreased. These results strongly confirmed that the degree of platelet activation was enhanced during acute asthmatic attack. The significance of platelet activation in the pathogenesis of asthma should be further investigated

  15. Aspirin decreases platelet uptake on Dacron vascular grafts in baboons

    International Nuclear Information System (INIS)

    Mackey, W.C.; Connolly, R.J.; Callow, A.D.

    1984-01-01

    The influence of a single dose of aspirin (5.4-7.4 mg/kg) on platelet uptake on 4-mm Dacron interposition grafts was studied in a baboon model using gamma camera scanning for 111-Indium labeled platelets. In vitro assessment of platelet function after aspirin administration revealed that in the baboon, as in the human, aspirin abolished arachidonic acid-induced platelet aggregation, prolonged the lag time between exposure to collagen and aggregation, and decreased plasma thromboxane B2 levels. Aspirin also prolonged the template bleeding time. Scans for 111-Indium labeled platelets revealed that pretreatment with a single dose of aspirin decreased platelet uptake on 4-mm Dacron carotid interposition grafts. This decrease in platelet uptake was associated with a significant improvement in 2-hour graft patency and with a trend toward improved 2-week patency

  16. Effects of alcohol on platelet functions.

    Science.gov (United States)

    Renaud, S C; Ruf, J C

    1996-03-15

    Recent epidemiologic studies have consistently shown that moderate intake of alcoholic beverages protect against morbidity and mortality from coronary heart disease and ischemic stroke. By contrast, alcohol drinking may also predispose to cerebral hemorrhage. These observations suggest an effect of alcohol similar to that of aspirin. Several studies in humans and animals have shown that the immediate effect of alcohol, either added in vitro to platelets or 10 to 20 min after ingestion, is to decrease platelet aggregation in response to most agonists (thrombin, ADP, epinephrine, collagen). Several hours later, as, in free-living populations deprived of drinking since the previous day it is mostly secondary aggregation to ADP and epinephrine and aggregation to collagen that are still inhibited in alcohol drinkers. By contrast, in binge drinkers or in alcoholics after alcohol withdrawal, response to aggregation, especially that induced by thrombin, is markedly increased. This rebound phenomenon, easily reproduced in rats, may explain ischemic strokes or sudden death known to occur after episodes of drunkenness. The platelet rebound effect of alcohol drinking was not observed with moderate red wine consumption in man. The protection afforded by wine has been recently duplicated in rats by grape tannins added to alcohol. This protection was associated with a decrease in the level of conjugated dienes, the first step in lipid peroxidation. In other words, wine drinking does not seem to be associated with the increased peroxidation usually observed with spirit drinking. Although further studies are required, the platelet rebound effect of alcohol drinking could be associated with an excess of lipid peroxides known to increase platelet reactivity, especially to thrombin.

  17. Anomalous columnar order of charged colloidal platelets

    Science.gov (United States)

    Morales-Anda, L.; Wensink, H. H.; Galindo, A.; Gil-Villegas, A.

    2012-01-01

    Monte Carlo computer simulations are carried out for a model system of like-charged colloidal platelets in the isothermal-isobaric ensemble (NpT). The aim is to elucidate the role of electrostatic interactions on the structure of synthetic clay systems at high particle densities. Short-range repulsions between particles are described by a suitable hard-core model representing a discotic particle. This potential is supplemented with an electrostatic potential based on a Yukawa model for the screened Coulombic potential between infinitely thin disklike macro-ions. The particle aspect-ratio and electrostatic parameters were chosen to mimic an aqueous dispersion of thin, like-charged, rigid colloidal platelets at finite salt concentration. An examination of the fluid phase diagram reveals a marked shift in the isotropic-nematic transition compared to the hard cut-sphere reference system. Several statistical functions, such as the pair correlation function for the center-of-mass coordinates and structure factor, are obtained to characterize the structural organization of the platelets phases. At low salinity and high osmotic pressure we observe anomalous hexagonal columnar structures characterized by interpenetrating columns with a typical intercolumnar distance corresponding to about half of that of a regular columnar phase. Increasing the ionic strength leads to the formation of glassy, disordered structures consisting of compact clusters of platelets stacked into finite-sized columns. These so-called "nematic columnar" structures have been recently observed in systems of charge-stabilized gibbsite platelets. Our findings are corroborated by an analysis of the static structure factor from a simple density functional theory.

  18. Platelet associated IgG, platelet mean life span and treatment with intravenous immunoglobulin in idiopathic thrombocytopenic purpura

    International Nuclear Information System (INIS)

    Nieminen, U.; Syrjaelae, M.; Ikkala, E.; Myllylae, G.

    1988-01-01

    The clinical significance of platelet associated IgG in ITP detected by direct platelet suspension immunofluorescence test (PSIFT) was studied. The platelet mean life span (MLS) was measured with 111 In-labelled platelets in 17 adult patients. All the patients had shortened platelet MLS. The direct PSIFT was positive in 14 patients. Patients were initially treated with prednisone; 12 patients with poor response to the drug were splenectomised. 8 of these 12 patients were treated with intravenous immunoglobulin (IvIg) before splenectomy. The response to IvIg was as good or better in the 3 patients with negative PSIFT, than in the 5 patients with positive PSIFT. (author)

  19. Genetic Variants in CPA6 and PRPF31 are Associated with Variation in Response to Metformin in Individuals with Type 2 Diabetes.

    Science.gov (United States)

    Rotroff, Daniel M; Yee, Sook Wah; Zhou, Kaixin; Marvel, Skylar W; Shah, Hetal S; Jack, John R; Havener, Tammy M; Hedderson, Monique M; Kubo, Michiaki; Herman, Mark A; Gao, He; Mychaleckyi, Josyf C; McLeod, Howard L; Doria, Alessandro; Giacomini, Kathleen M; Pearson, Ewan R; Wagner, Michael J; Buse, John B; Motsinger-Reif, Alison A

    2018-04-12

    Metformin is the first line treatment for type 2 diabetes (T2D). Although widely prescribed, the glucose-lowering mechanism for metformin is incompletely understood. Here we used a genome-wide association approach in a diverse group of individuals with T2D from the Action to Control Cardiovascular Risk in Diabetes (ACCORD) clinical trial to identify common and rare variants associated with HbA1c response to metformin treatment, and followed up these findings in four replication cohorts. Common variants in PRPF31 and CPA6 , were associated with worse and better metformin response, respectively (p<5×10 -6 ), and meta-analysis in independent cohorts displayed similar associations with metformin response (p=1.2×10 -8 and p=0.005, respectively). Previous studies have shown that PRPF31 (+/-) knockout mice have increased total body fat (p=1.78×10 -6 ) and increased fasted circulating glucose (p=5.73×10 -6 ). Furthermore, rare variants in STAT3 associated with worse metformin response( q <0.1). STAT3 is a ubiquitously expressed pleiotropic transcriptional activator that participates in the regulation of metabolism and feeding behavior. Here we provide novel evidence for associations of common and rare variants in PRPF31, CPA6, and STAT3 with metformin response that may provide insight into mechanisms important for metformin efficacy in T2D. © 2018 by the American Diabetes Association.

  20. Thrombopoietin contributes to enhanced platelet activation in cigarette smokers.

    Science.gov (United States)

    Lupia, Enrico; Bosco, Ornella; Goffi, Alberto; Poletto, Cesare; Locatelli, Stefania; Spatola, Tiziana; Cuccurullo, Alessandra; Montrucchio, Giuseppe

    2010-05-01

    Thrombopoietin (TPO) is a humoral growth factor that primes platelet activation in response to several agonists. We recently showed that TPO enhances platelet activation in unstable angina and sepsis. Aim of this study was to investigate the role of TPO in platelet function abnormalities described in cigarette smokers. In a case-control study we enrolled 20 healthy cigarette smokers and 20 nonsmokers, and measured TPO and C-reactive protein (CRP), as well as platelet-leukocyte binding and P-selectin expression. In vitro we evaluated the priming activity of smoker or control plasma on platelet activation, and the role of TPO in this effect. We then studied the effects of acute smoking and smoking cessation on TPO levels and platelet activation indices. Chronic cigarette smokers had higher circulating TPO levels than nonsmoking controls, as well as increased platelet-leukocyte binding, P-selectin expression, and CRP levels. Serum cotinine concentrations correlated with TPO concentrations, platelet-monocyte aggregates and P-selectin expression. In addition, TPO levels significantly correlated with ex vivo platelet-monocyte aggregation and P-selectin expression. In vitro, the plasma from cigarette smokers, but not from nonsmoking controls, primed platelet-monocyte binding, which was reduced when an inhibitor of TPO was used. We also found that acute smoking slightly increased TPO levels, but did not affect platelet-leukocyte binding, whereas smoking cessation induced a significant decrease in both circulating TPO and platelet-leukocyte aggregation. Elevated TPO contributes to enhance platelet activation and platelet-monocyte cross-talk in cigarette smokers. Copyright 2009 Elsevier Ireland Ltd. All rights reserved.

  1. Differences in levels of platelet-derived microparticles in platelet components prepared using the platelet rich plasma, buffy coat, and apheresis procedures.

    Science.gov (United States)

    Noulsri, Egarit; Udomwinijsilp, Prapaporn; Lerdwana, Surada; Chongkolwatana, Viroje; Permpikul, Parichart

    2017-04-01

    There has been an increased interest in platelet-derived microparticles (PMPs) in transfusion medicine. Little is known about PMP status during the preparation of platelet concentrates for transfusion. The aim of this study is to compare the PMP levels in platelet components prepared using the buffy coat (BC), platelet-rich plasma platelet concentrate (PRP-PC), and apheresis (AP) processes. Platelet components were prepared using the PRP-PC and BC processes. Apheresis platelets were prepared using the Trima Accel and Amicus instruments. The samples were incubated with annexin A5-FITC, CD41-PE, and CD62P-APC. At day 1 after processing, the PMPs and activated platelets were determined using flow cytometry. Both the percentage and number of PMPs were higher in platelet components prepared using the Amicus instrument (2.6±1.8, 32802±19036 particles/μL) than in platelet components prepared using the Trima Accel instrument (0.5±0.4, 7568±5298 particles/μL), BC (1.2±0.6, 12,920±6426 particles/μL), and PRP-PC (0.9±0.6, 10731±5514 particles/μL). Both the percentage and number of activated platelets were higher in platelet components prepared using the Amicus instrument (33.2±13.9, 427553±196965 cells/μL) than in platelet components prepared using the Trima Accel instrument (16.2±6.1, 211209±87706 cells/μL), BC (12.9±3.2, 140624±41003 cells/μL), and PRP-PC (21.1±6.3, 265210±86257 cells/μL). The study suggests high variability of PMPs and activated platelets in platelet components prepared using different processes. This result may be important in validating the instruments involved in platelet blood collection and processing. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Nuclear power plant analyzer

    International Nuclear Information System (INIS)

    Stritar, A.

    1986-01-01

    The development of Nuclear Power Plant Analyzers in USA is described. There are two different types of Analyzers under development in USA, the forst in Idaho and Los Alamos national Lab, the second in brookhaven National lab. That one is described in detail. The computer hardware and the mathematical models of the reactor vessel thermalhydraulics are described. (author)

  3. Analyzing Peace Pedagogies

    Science.gov (United States)

    Haavelsrud, Magnus; Stenberg, Oddbjorn

    2012-01-01

    Eleven articles on peace education published in the first volume of the Journal of Peace Education are analyzed. This selection comprises peace education programs that have been planned or carried out in different contexts. In analyzing peace pedagogies as proposed in the 11 contributions, we have chosen network analysis as our method--enabling…

  4. Analyzing in the present

    DEFF Research Database (Denmark)

    Revsbæk, Line; Tanggaard, Lene

    2015-01-01

    The article presents a notion of “analyzing in the present” as a source of inspiration in analyzing qualitative research materials. The term emerged from extensive listening to interview recordings during everyday commuting to university campus. Paying attention to the way different parts of vari...

  5. Gearbox vibration diagnostic analyzer

    Science.gov (United States)

    1992-01-01

    This report describes the Gearbox Vibration Diagnostic Analyzer installed in the NASA Lewis Research Center's 500 HP Helicopter Transmission Test Stand to monitor gearbox testing. The vibration of the gearbox is analyzed using diagnostic algorithms to calculate a parameter indicating damaged components.

  6. Fruitone CPA para retardar la maduración en piña Ananas comosus (L. Merr., cv. Cayena Lisa, cosechada en primavera Fruitone CPA for delay the fruit maturity of pineapple Ananas comosus (L Merr. cv. Smooth Cayenne harvested in spring time

    Directory of Open Access Journals (Sweden)

    ANDRÉS REBOLLEDO-MARTÍNEZ

    2002-08-01

    Full Text Available El objetivo fue determinar el efecto de dosis y número de aplicaciones de Fruitone CPA (ácido 2-3 clorofenoxi-propiónico en el retraso de la maduración, rendimiento y calidad del fruto de piña en el periodo de primavera. El experimento se llevó al cabo en el Campo Experimental Papaloapan, del INIFAP, en Veracruz, México. Se estableció con el cv. Cayena Lisa de México, en un diseño de bloques al azar con cuatro repeticiones; los tratamientos fueron nueve, incluido el testigo sin aplicación, 300, 600, 900 y 1200 mL por hectárea en una aplicación y 600, 900, 1500 y 2100 mL por hectárea divididas en dos aplicaciones iguales, espaciadas ocho días, de Fruitone CPA; los tratamientos se establecieron a los 135 días después de la inducción floral, a 65 días antes de la cosecha del testigo. Los resultados muestran un alto y significativo efecto del Fruitone en el peso de la fruta, aunque no hubo diferencias entre el número de aplicaciones; el contenido de ácido cítrico y los sólidos solubles totales se incrementaron con la aplicación del Fruitone. No se presentaron frutos agrietados ni con Mancha Café interna en ningún tratamiento. El retraso de la cosecha con respecto al testigo varió desde los seis hasta los 21 días, en función de la dosis. Se concluye que el mejor tratamiento fue el de 900 mL de Fruitone CPA por hectárea, en una sola aplicación, el cual incrementó el peso del fruto en un 14% y retrasó la cosecha 19 días.The objective of this research was to evaluate the effect of rates and applications of Fruitone CPA (acid 2-3 clorofenoxi -propionic over maturity delay, yield and quality of the pineapple fruit in spring time. The experiment was carried out in the Campo Experimental Papaloapan (INIFAP, in Veracruz State, Mexico. It was established with the cv. Smooth Cayenne, in randomized blocks, design with four replicates; totalizing nine treatments including, the control: 300, 600, 900 and 1200 mL of Fruitone CPA

  7. Increased platelet reactivity is associated with circulating platelet-monocyte complexes and macrophages in human atherosclerotic plaques.

    Directory of Open Access Journals (Sweden)

    Bert Rutten

    Full Text Available Platelet reactivity, platelet binding to monocytes and monocyte infiltration play a detrimental role in atherosclerotic plaque progression. We investigated whether platelet reactivity was associated with levels of circulating platelet-monocyte complexes (PMCs and macrophages in human atherosclerotic carotid plaques.Platelet reactivity was determined by measuring platelet P-selectin expression after platelet stimulation with increasing concentrations of adenosine diphosphate (ADP, in two independent cohorts: the Circulating Cells cohort (n = 244 and the Athero-Express cohort (n = 91. Levels of PMCs were assessed by flow cytometry in blood samples of patients who were scheduled for percutaneous coronary intervention (Circulating Cells cohort. Monocyte infiltration was semi-quantitatively determined by histological examination of atherosclerotic carotid plaques collected during carotid endarterectomy (Athero-Express cohort.We found increased platelet reactivity in patients with high PMCs as compared to patients with low PMCs (median (interquartile range: 4153 (1585-11267 area under the curve (AUC vs. 9633 (3580-21565 AUC, P<0.001. Also, we observed increased platelet reactivity in patients with high macrophage levels in atherosclerotic plaques as compared to patients with low macrophage levels in atherosclerotic plaques (mean ± SD; 8969 ± 3485 AUC vs. 7020 ± 3442 AUC, P = 0.02. All associations remained significant after adjustment for age, sex and use of drugs against platelet activation.Platelet reactivity towards ADP is associated with levels of PMCs and macrophages in human atherosclerotic carotid plaques.

  8. Gallic Acid Attenuates Platelet Activation and Platelet-Leukocyte Aggregation: Involving Pathways of Akt and GSK3β

    Science.gov (United States)

    Chang, Shih-Sheng; Lee, Viola S. Y.; Tseng, Yu-Lun; Chang, Kuan-Cheng; Chen, Kuen-Bao; Chen, Yuh-Lien; Li, Chi-Yuan

    2012-01-01

    Platelet activation and its interaction with leukocytes play an important role in atherothrombosis. Cardiovascular diseases resulted from atherothrombosis remain the major causes of death worldwide. Gallic acid, a major constituent of red wine and tea, has been believed to have properties of cardiovascular protection, which is likely to be related to its antioxidant effects. Nonetheless, there were few and inconsistent data regarding the effects of gallic acid on platelet function. Therefore, we designed this in vitro study to determine whether gallic acid could inhibit platelet activation and the possible mechanisms. From our results, gallic acid could concentration-dependently inhibit platelet aggregation, P-selectin expression, and platelet-leukocyte aggregation. Gallic acid prevented the elevation of intracellular calcium and attenuated phosphorylation of PKCα/p38 MAPK and Akt/GSK3β on platelets stimulated by the stimulants ADP or U46619. This is the first mechanistic explanation for the inhibitory effects on platelets from gallic acid. PMID:22811749

  9. Gallic Acid Attenuates Platelet Activation and Platelet-Leukocyte Aggregation: Involving Pathways of Akt and GSK3β

    Directory of Open Access Journals (Sweden)

    Shih-Sheng Chang

    2012-01-01

    Full Text Available Platelet activation and its interaction with leukocytes play an important role in atherothrombosis. Cardiovascular diseases resulted from atherothrombosis remain the major causes of death worldwide. Gallic acid, a major constituent of red wine and tea, has been believed to have properties of cardiovascular protection, which is likely to be related to its antioxidant effects. Nonetheless, there were few and inconsistent data regarding the effects of gallic acid on platelet function. Therefore, we designed this in vitro study to determine whether gallic acid could inhibit platelet activation and the possible mechanisms. From our results, gallic acid could concentration-dependently inhibit platelet aggregation, P-selectin expression, and platelet-leukocyte aggregation. Gallic acid prevented the elevation of intracellular calcium and attenuated phosphorylation of PKCα/p38 MAPK and Akt/GSK3β on platelets stimulated by the stimulants ADP or U46619. This is the first mechanistic explanation for the inhibitory effects on platelets from gallic acid.

  10. Evaluation of performance of veterinary in-clinic hematology analyzers.

    Science.gov (United States)

    Rishniw, Mark; Pion, Paul D

    2016-12-01

    A previous study provided information regarding the quality of in-clinic veterinary biochemistry testing. However, no similar studies for in-clinic veterinary hematology testing have been conducted. The objective of this study was to assess the quality of hematology testing in veterinary in-clinic laboratories using results obtained from testing 3 levels of canine EDTA blood samples. Clinicians prepared blood samples to achieve measurand concentrations within, below, and above their RIs and evaluated the samples in triplicate using their in-clinic analyzers. Quality was assessed by comparison of calculated total error with quality requirements, determination of sigma metrics, use of a quality goal index, and agreement between in-clinic and reference laboratory instruments. Suitability for statistical quality control was determined using adaptations from the computerized program, EZRules3. Evaluation of 10 veterinary in-clinic hematology analyzers showed that these instruments often fail to meet quality requirements. At least 60% of analyzers reasonably determined RBC, WBC, HCT, and HGB, when assessed by most quality goal criteria; platelets were less reliably measured, with 80% deemed suitable for low platelet counts, but only 30% for high platelet counts, and automated differential leukocyte counts were generally considered unsuitable for clinical use with fewer than 40% of analyzers meeting the least stringent quality goal requirements. Fewer than 50% of analyzers were able to meet requirements for statistical quality control for any measurand. These findings reflect the current status of in-clinic hematology analyzer performance and provide a basis for future evaluations of the quality of veterinary laboratory testing. © 2016 American Society for Veterinary Clinical Pathology.

  11. Gamma-glutamyl-transpeptidase to platelet ratio is not superior to APRI,FIB-4 and RPR for diagnosing liver fibrosis in CHB patients in China

    OpenAIRE

    Huang, Rui; Wang, Guiyang; Tian, Chen; Liu, Yong; Jia, Bei; Wang, Jian; Yang, Yue; Li, Yang; Sun, Zhenhua; Yan, Xiaomin; Xia, Juan; Xiong, Yali; Song, Peixin; Zhang, Zhaoping; Ding, Weimao

    2017-01-01

    The gamma-glutamyl transpeptidase to platelet ratio (GPR) is a novel index to estimate liver fibrosis in chronic hepatitis B (CHB). Few studies compared diagnostic accuracy of GPR with other non-invasive fibrosis tests based on blood parameters. We analyzed diagnostic values of GPR for detecting liver fibrosis and compared diagnostic performances of GPR with APRI (aspartate aminotransferase-to-platelet ratio index), FIB-4 (fibrosis index based on the four factors), NLR (neutrophil-to-lymphocy...

  12. Negative feedback regulation of human platelets via autocrine activation of the platelet-derived growth factor alpha-receptor.

    Science.gov (United States)

    Vassbotn, F S; Havnen, O K; Heldin, C H; Holmsen, H

    1994-05-13

    Human platelets contain platelet-derived growth factor (PDGF) in their alpha-granules which is released during platelet exocytosis. We show by immunoprecipitation and 125I-PDGF binding experiments that human platelets have functionally active PDGF alpha-receptors, but not beta-receptors. The PDGF alpha-receptor (PDGFR-alpha) was identified as a 170-kDa glycosylated protein-tyrosine kinase as found in other cell types. Stimulation of platelets with 0.1 unit/ml thrombin resulted in a significant increase (2-5-fold) of the tyrosine phosphorylation of the PDGFR-alpha, as determined by immunoprecipitation with phosphotyrosine antiserum as well as with PDGFR-alpha antiserum. The observed thrombin-induced autophosphorylation of the PDGFR-alpha was inhibited by the addition of a neutralizing monoclonal PDGF antibody. Thus, our results suggest that the platelet PDGFR-alpha is stimulated in an autocrine manner by PDGF secreted during platelet activation. Preincubation of platelets with PDGF inhibited thrombin-induced platelet aggregation and secretion of ATP + ADP and beta-hexosaminidase. Thrombin-induced platelet aggregation was also reversed when PDGF was added 30 s after thrombin stimulation. Inhibition of the autocrine PDGF pathway during platelet activation by the PDGF antibody led to a potentiation of thrombin-induced beta-hexosaminidase secretion. Thus, the PDGFR-alpha takes part in a negative feedback regulation during platelet activation. Our demonstration of PDGF alpha-receptors on human platelets and its inhibitory function during platelet activation identifies a new possible role of PDGF in the regulation of thrombosis.

  13. Modelling phase equilibria for acid gas mixtures using the CPA equation of state. Part VI. Multicomponent mixtures with glycols relevant to oil and gas and to liquid or supercritical CO2 transport applications

    DEFF Research Database (Denmark)

    Tsivintzelis, Ioannis; Kontogeorgis, Georgios M.

    2016-01-01

    to data on ternary and multicomponent mixtures) to model the phase behaviour of ternary and quaternary systems with CO2 and glycols. It is concluded that CPA performs satisfactorily for most multicomponent systems considered. Some differences between the various modelling approaches are observed....... This work is the last part of a series of studies, which aim to arrive in a single "engineering approach" for applying CPA to acid gas mixtures, without introducing significant changes to the model. An overall assessment, based also on the obtained results of this series (Tsivintzelis et al., 2010, 2011...

  14. Automated platelet collection using the latest apheresis devices in an Indian setting.

    Science.gov (United States)

    Agarwal, Prashant; Verma, Anupam

    2009-10-01

    In a developing nation like India where there is a scarcity of resources and voluntary donors, provision of safe and good quality blood and its components is a huge challenge. The demand for platelets is increasing constantly due to better management of various patient categories, specifically hemato-oncological cases, where there is an increased demand of platelet transfusion. The use of apheresis single donor platelets (SDPs) has been attributed to increased gap between demand and supply of whole blood derived random donor platelets (RDPs). Moreover, the other benefits of SDPs such as decreased donor exposure and simplification of inventory management cannot be overlooked. However, the increased costs and logistic problems, compounded by the lack of awareness, limit the donor recruitment and procedures for SDPs. In Indian scenario, there are no specific guidelines or standards available which can be followed, while simultaneously addressing the associated problems. In this review, we have tried to analyze the various problems of donor selection, donor safety and the quality issues regarding plateletpheresis. Based on this we have tried to give certain recommendations which might help the centers in resolving the problems related to plateletpheresis.

  15. Markers for vulnerability to psychopathology: Temperament traits associated with platelet MAO activity

    International Nuclear Information System (INIS)

    Schalling, D.; Aasberg, M.; Edman, G.; Oreland, L.

    1987-01-01

    The functional linkage between platelet MAO activity and psychopathology was explored by analyzing temperamental correlates in 40 male subjects by means of scales from the Eysenck Personality Questionnaire (EPQ), the Zuckerman Sensation Seeking Inventory, and the Karolinska Scales of Personality (KSP). Linear correlation were found with two sensation seeking scales, replicating earlier findings. However, nonlinear correlations predominated. Subjects with intemediate platelet MAO activity had higher scores in conformity scales and lower scores in anxiety and hostility scales than low and high MAO subgroups. Low MAO subjects showed a pattern of higher scores in KSP Impulsiveness, EPQ Neuroticism, and KSP Somatic Anxiety and Irritability and lower scores in KSP Socialization, in line with personality profiles found in alcoholics, phychopaths, and suicide attempters who also tend to have low platelet MAO activity. High MAO subject scored lower in sensation seeking and conformity scales and higher in KSP Phychasthenia, Muscular Tension and Suspicion scales, consistent with clinical links between high platelet MAO activity and anxiety and paranoia. (author)

  16. Cyclophilin B binding to platelets supports calcium-dependent adhesion to collagen.

    Science.gov (United States)

    Allain, F; Durieux, S; Denys, A; Carpentier, M; Spik, G

    1999-08-01

    We have recently reported that cyclophilin B (CyPB), a secreted cyclosporine-binding protein, could bind to T lymphocytes through interactions with two types of binding sites. The first ones, referred to as type I, involve interactions with the conserved domain of CyPB and promote the endocytosis of surface-bound ligand, while the second type of binding sites, termed type II, are represented by glycosaminoglycans (GAG). Here, we further investigated the interactions of CyPB with blood cell populations. In addition to lymphocytes, CyPB was found to interact mainly with platelets. The binding is specific, with a dissociation constant (kd) of 9 +/- 3 nmol/L and the number of sites estimated at 960 +/- 60 per cell. Platelet glycosaminoglycans are not required for the interactions, but the binding is dramatically reduced by active cyclosporine derivatives. We then analyzed the biologic effects of CyPB and found a significant increase in platelet adhesion to collagen. Concurrently, CyPB initiates a transmembranous influx of Ca(2+) and induces the phosphorylation of the P-20 light chains of myosin. Taken together, the present results demonstrate for the first time that extracellular CyPB specifically interacts with platelets through a functional receptor related to the lymphocyte type I binding sites and might act by regulating the activity of a receptor-operated membrane Ca(2+) channel.

  17. Constitutive modeling of the rheological behavior of platelet suspensions

    Science.gov (United States)

    Sommer, Drew E.

    Compression molding of chopped fiber composites is used to manufacture complex 3D geometries with high fiber volume fractions of 50-60% and long, discontinuous fibers and thermoplastic matrices. When prepreg, chopped into platelets, is used as a charge material, the individual platelets remain intact during the molding process and flow relative to one another, as experimental observations show. Heterogeneity of the platelet/resin suspension cannot be considered at the structural scale of molding simulation. Instead, the suspension should be idealized into the homogenized anisotropic and viscous system which obeys the prescribed anisotropic stress-strain rate constitutive relation. The viscosity tensor of the aforementioned constitutive law was analytically evaluated in this work through the representative volume element (RVE) based analysis. An idealized microstructure of platelets was developed to perform such an analysis. The platelets were aligned and arranged in a planar configuration with periodic boundary conditions. Analytic expressions for the effective, anisotropic viscosities were derived by micromechanical analysis for the idealized microstructure of rigid platelets. In this analysis, the load transfer mechanisms and their contribution to the viscosity of the platelet assembly were investigated. The kinematic assumption of linear velocity distributions consistent with the mechanism of shearing rate was adopted. While the platelets were assumed to be rigid, the resin was taken as an incompressible, isotropic fluid which provided for the platelet-to-platelet load transfer. Strain rate and temperature dependence were included by modeling the polymer matrix as a Carreau fluid. Shear strain in the resin was developed due to the relative motion of adjacent platelets. The resin shear strain rate was expressed in terms of the corresponding platelet velocities. Equilibrium of the platelet was used to relate the applied far-field stress to the average strain rate

  18. Miniature mass analyzer

    CERN Document Server

    Cuna, C; Lupsa, N; Cuna, S; Tuzson, B

    2003-01-01

    The paper presents the concept of different mass analyzers that were specifically designed as small dimension instruments able to detect with great sensitivity and accuracy the main environmental pollutants. The mass spectrometers are very suited instrument for chemical and isotopic analysis, needed in environmental surveillance. Usually, this is done by sampling the soil, air or water followed by laboratory analysis. To avoid drawbacks caused by sample alteration during the sampling process and transport, the 'in situ' analysis is preferred. Theoretically, any type of mass analyzer can be miniaturized, but some are more appropriate than others. Quadrupole mass filter and trap, magnetic sector, time-of-flight and ion cyclotron mass analyzers can be successfully shrunk, for each of them some performances being sacrificed but we must know which parameters are necessary to be kept unchanged. To satisfy the miniaturization criteria of the analyzer, it is necessary to use asymmetrical geometries, with ion beam obl...

  19. Platelet Function Tests: Preanalytical Variables, Clinical Utility, Advantages, and Disadvantages.

    Science.gov (United States)

    Hvas, Anne-Mette; Grove, Erik Lerkevang

    2017-01-01

    Platelet function tests are mainly used in the diagnostic work-up of platelet disorders. During the last decade, the additional use of platelet function tests to evaluate the effect of antiplatelet therapy has also emerged in an attempt to identify patients with an increased risk of arterial thrombosis. Furthermore, platelet function tests are increasingly used to measure residual effect of antiplatelet therapy prior to surgery with the aim of reducing the risk of bleeding. To a limited extend, platelet function tests are also used to evaluate hyperaggregability as a potential marker of a prothrombotic state outside the setting of antiplatelet therapy. This multifaceted use of platelet function tests and the development of simpler point-of-care tests with narrower application have increased the use of platelet function testing and also facilitated the use of platelet function tests outside the highly specialized laboratories. The present chapter describes the preanalytical variables, which should be taken into account when planning platelet function testing. Also, the most widely used platelet function tests are introduced, and their clinical utility and their relative advantages and disadvantages are discussed.

  20. Progress in bio-manufacture of platelets for transfusion.

    Science.gov (United States)

    Heazlewood, Shen Y; Nilsson, Susan K; Cartledge, Kellie; Be, Cheang Ly; Vinson, Andrew; Gel, Murat; Haylock, David N

    2017-11-01

    Blood transfusion services face an ever-increasing demand for donor platelets to meet clinical needs. Whilst strategies for increasing platelet storage life and improving the efficiency of donor platelet collection are important, in the longer term, platelets generated by bio-manufacturing processes will be required to meet demands. Production of sufficient numbers of in vitro-derived platelets for transfusion represents a significant bioengineering challenge. In this review, we highlight recent progress in this area of research and outline the main technical and biological obstacles that need to be met before this becomes feasible and economic. A critical consideration is assurance of the functional properties of these cells as compared to their fresh, donor collected, counterparts. We contend that platelet-like particles and in vitro-derived platelets that phenotypically resemble fresh platelets must deliver the same functions as these cells upon transfusion. We also note recent progress with immortalized megakaryocyte progenitor cell lines, molecular strategies for reducing expression of HLA Class I to generate universal donor platelets and the move to early clinical studies with in vitro-derived platelets.

  1. The interaction of thrombin with platelet protease nexin

    International Nuclear Information System (INIS)

    Knupp, C.L.

    1989-01-01

    Thrombin interacts with a platelet protein which is immunologically related to fibroblast protease nexin and has been termed platelet protease nexin I (PNI). Conflicting hypotheses about the relationship of the thrombin-PNI complex formation to platelet activation have been proposed. The studies presented here demonstrate that the platelet-associated and supernatant complexes with added 125I-thrombin are formed only under conditions which produce platelet activation in normal and chymotrypsin-modified platelets. The platelet-associated complex is formed prior to the appearance of complexes in supernatants. Appearance of the supernatant complex coincides with the appearance of thrombospondin in the reaction supernatants. Excess native thrombin, dansylarginine N-(3-ethyl-1,5-pentanediyl) amide or hirudin can prevent radiolabeled platelet-associated complex formation if added before 125I-thrombin. DAPA or hirudin can prevent or dissociate complex formation if added up to one minute after thrombin but not at later time points. The surface associated complex is accessible to trypsin although a portion remains with the cytoskeletal proteins when thrombin-activated platelets are solubilized with Triton X 100. The surface-associated complex formation parallels many aspects of the specific measurable thrombin binding, yet it does not appear to involve other identified surface glycoprotein thrombin receptors or substrates. Although the time course of appearance of the complexes in supernatants is consistent with other data which suggest that PNI may be released from platelet granules during platelet activation, other explanations for the appearance of PNI on the platelet surface and in supernatants during platelet activation are possible

  2. [Inhibitory mechanism of ifenprodil tartrate on rabbit platelet aggregation].

    Science.gov (United States)

    Irino, O; Saitoh, K; Hayashi, T; Ohkubo, K

    1985-05-01

    The effects of dl-erythro-4-benzyl-alpha-(4-hydroxyphenyl)-beta-methyl-l-piperidine-eth anol tartrate (ifenprodil tartrate) on rabbit platelet aggregation in vitro and ex vivo were studied. Ifenprodil tartrate inhibited platelet aggregation in vitro induced by ADP, collagen and epinephrine. It also inhibited 5-hydroxytryptamine (5-HT) uptake into platelets and 5-HT release from platelets. Since these inhibitory effects of ifenprodil tartrate on the functions of rabbit platelets were similar to the effects of imipramine, the effects of ifenprodil tartrate may be due to the stabilizing action of ifenprodil tartrate on the platelet membrane. The platelet aggregation by ADP was significantly inhibited in rabbits after oral administration of ifenprodil tartrate, the maximal plasma level of ifenprodil being reached at 20 ng/ml ex vivo, while the maximal level was only 1/40 of the minimal concentration of ifenprodil tartrate necessary to inhibit platelet aggregation in vitro. These results indicate that factors other than ifenprodil tartrate acting directly on the platelets (e.g., PGI2 which is an endogenous inhibitor of platelet aggregation) are involved in inducing the inhibitory effects of ifenprodil tartrate on platelet aggregation ex vivo. The effects of ifenprodil tartrate on both PGI2 release from the aorta and the inhibitory effects of PGI2 on platelet aggregation in vitro were investigated: PGI2 was found to intensify the inhibitory effects of ifenprodil tartrate on platelet aggregation in vitro, but there was little effect, if any, on PGI2 release. Therefore, it is considered that the ex vivo effects of ifenprodil tartrate might be due to its interaction with endogenous PGI2 in the blood.

  3. Reduction of relative centrifugation force within injectable platelet-rich-fibrin (PRF) concentrates advances patients' own inflammatory cells, platelets and growth factors: the first introduction to the low speed centrifugation concept.

    Science.gov (United States)

    Choukroun, J; Ghanaati, S

    2018-02-01

    The aim of this study was to analyze systematically the influence of the relative centrifugation force (RCF) on leukocytes, platelets and growth factor release within fluid platelet-rich fibrin matrices (PRF). Systematically using peripheral blood from six healthy volunteers, the RCF was reduced four times for each of the three experimental protocols (I-III) within the spectrum (710-44 g), while maintaining a constant centrifugation time. Flow cytometry was applied to determine the platelets and leukocyte number. The growth factor concentration was quantified 1 and 24 h after clotting using ELISA. Reducing RCF in accordance with protocol-II (177 g) led to a significantly higher platelets and leukocytes numbers compared to protocol-I (710 g). Protocol-III (44 g) showed a highly significant increase of leukocytes and platelets number in comparison to -I and -II. The growth factors' concentration of VEGF and TGF-β1 was significantly higher in protocol-II compared to -I, whereas protocol-III exhibited significantly higher growth factor concentration compared to protocols-I and -II. These findings were observed among 1 and 24 h after clotting, as well as the accumulated growth factor concentration over 24 h. Based on the results, it has been demonstrated that it is possible to enrich PRF-based fluid matrices with leukocytes, platelets and growth factors by means of a single alteration of the centrifugation settings within the clinical routine. We postulate that the so-called low speed centrifugation concept (LSCC) selectively enriches leukocytes, platelets and growth factors within fluid PRF-based matrices. Further studies are needed to evaluate the effect of cell and growth factor enrichment on wound healing and tissue regeneration while comparing blood concentrates gained by high and low RCF.

  4. Concentration of platelets and growth factors in platelet-rich plasma from Goettingen minipigs.

    Science.gov (United States)

    Jungbluth, Pascal; Grassmann, Jan-Peter; Thelen, Simon; Wild, Michael; Sager, Martin; Windolf, Joachim; Hakimi, Mohssen

    2014-01-01

    In minipigs little is known about the concentration of growth factors in plasma, despite their major role in several patho-physiological processes such as healing of fractures. This prompted us to study the concentration of platelets and selected growth factors in plasma and platelet-rich plasma (PRP) preparation of sixteen Goettingen minipigs. Platelet concentrations increased significantly in PRP in comparison to native blood plasma. Generally, significant increase in the concentration of all growth factors tested was observed in the PRP in comparison to the corresponding plasma or serum. Five of the plasma samples examined contained detectable levels of bone morphogenic protein 2 (BMP-2) whereas eleven of the plasma or serum samples contained minimal amounts of vascular endothelial growth factor (VEGF) and platelet-derived growth factor (PDGF-bb) respectively. On the other hand variable concentrations of bone morphogenic protein 7 (BMP-7) and transforming growth factor β1 (TGF-β1) were measured in all plasma samples. In contrast, all PRP samples contained significantly increased amounts of growth factors. The level of BMP-2, BMP-7, TGF-β1, VEGF and PDGF-bb increased by 17.6, 1.5, 7.1, 7.2 and 103.3 fold, in comparison to the corresponding non-enriched preparations. Moreover significant positive correlations were found between platelet count and the concentrations of BMP-2 (r=0.62, pplatelet-rich plasma of minipigs which might thus serve as a source of autologous growth factors.

  5. A novel platelet concentrate: titanium-prepared platelet-rich fibrin.

    Science.gov (United States)

    Tunalı, Mustafa; Özdemir, Hakan; Küçükodacı, Zafer; Akman, Serhan; Yaprak, Emre; Toker, Hülya; Fıratlı, Erhan

    2014-01-01

    We developed a new product called titanium-prepared platelet-rich fibrin (T-PRF). The T-PRF method is based on the hypothesis that titanium may be more effective in activating platelets than the silica activators used with glass tubes in Chouckroun's leukocyte- and platelet-rich fibrin (L-PRF) method. In this study, we aimed to define the structural characteristics of T-PRF and compare it with L-PRF. Blood samples were collected from 10 healthy male volunteers. The blood samples were drawn using a syringe. Nine milliliters was transferred to a dry glass tube, and 9 mL was transferred to a titanium tube. Half of each clot (i.e., the blood that was clotted using T-PRF or L-PRF) was processed with a scanning electron microscope (SEM). The other half of each clot was processed for fluorescence microscopy analysis and light microscopy analysis. The T-PRF samples seemed to have a highly organized network with continuous integrity compared to the other L-PRF samples. Histomorphometric analysis showed that T-PRF fibrin network covers larger area than L-PRF fibrin network; also fibrin seemed thicker in the T-PRF samples. This is the first human study to define T-PRF as an autogenous leukocyte- and platelet-rich fibrin product. The platelet activation by titanium seems to offer some high characteristics to T-PRF.

  6. A Novel Platelet Concentrate: Titanium-Prepared Platelet-Rich Fibrin

    Directory of Open Access Journals (Sweden)

    Mustafa Tunalı

    2014-01-01

    Full Text Available We developed a new product called titanium-prepared platelet-rich fibrin (T-PRF. The T-PRF method is based on the hypothesis that titanium may be more effective in activating platelets than the silica activators used with glass tubes in Chouckroun’s leukocyte- and platelet-rich fibrin (L-PRF method. In this study, we aimed to define the structural characteristics of T-PRF and compare it with L-PRF. Blood samples were collected from 10 healthy male volunteers. The blood samples were drawn using a syringe. Nine milliliters was transferred to a dry glass tube, and 9 mL was transferred to a titanium tube. Half of each clot (i.e., the blood that was clotted using T-PRF or L-PRF was processed with a scanning electron microscope (SEM. The other half of each clot was processed for fluorescence microscopy analysis and light microscopy analysis. The T-PRF samples seemed to have a highly organized network with continuous integrity compared to the other L-PRF samples. Histomorphometric analysis showed that T-PRF fibrin network covers larger area than L-PRF fibrin network; also fibrin seemed thicker in the T-PRF samples. This is the first human study to define T-PRF as an autogenous leukocyte- and platelet-rich fibrin product. The platelet activation by titanium seems to offer some high characteristics to T-PRF.

  7. Antimicrobial effect of platelet-rich plasma and platelet-rich fibrin.

    Science.gov (United States)

    Badade, Pallavi S; Mahale, Swapna A; Panjwani, Alisha A; Vaidya, Prutha D; Warang, Ayushya D

    2016-01-01

    Platelet concentrates have been extensively used in a variety of medical fields to promote soft- and hard-tissue regeneration. The significance behind their use lies in the abundance of growth factors (GFs) in platelets α-granules that promote wound healing. Other than releasing a pool of GFs upon activation, platelets also have many features that indicate their role in the anti-infective host defense. The aim of this study is to evaluate the antimicrobial activities of platelet-rich plasma (PRP) and platelet-rich fibrin (PRF) against periodontal disease-associated bacteria. Blood samples were obtained from ten adult male patients. PRP and PRF were procured using centrifugation. The antimicrobial activity of PRP and PRF was evaluated by microbial culturing using bacterial strains of Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans. P. gingivalis and A. actinomycetemcomitans were inhibited by PRP but not by PRF. PRP is a potentially useful substance in the fight against periodontal pathogens. This might represent a valuable property in adjunct to the enhancement of tissue regeneration.

  8. Increasing platelet concentrations in leukocyte-reduced platelet-rich plasma decrease collagen gene synthesis in tendons.

    Science.gov (United States)

    Boswell, Stacie G; Schnabel, Lauren V; Mohammed, Hussni O; Sundman, Emily A; Minas, Tom; Fortier, Lisa A

    2014-01-01

    Platelet-rich plasma (PRP) is used for the treatment of tendinopathy. There are numerous PRP preparations, and the optimal combination of platelets and leukocytes is not known. Within leukocyte-reduced PRP (lrPRP), there is a plateau effect of platelet concentration, with increasing platelet concentrations being detrimental to extracellular matrix synthesis. Controlled laboratory study. Different formulations of lrPRP with respect to the platelet:leukocyte ratio were generated from venous blood of 8 horses. Explants of the superficial digital flexor tendon were cultured in lrPRP products for 96 hours. Platelet-derived growth factor-BB (PDGF-BB), tumor necrosis factor-α (TNF-α), transforming growth factor-β1 (TGF-β1), and interleukin-1β (IL-1β) concentrations were determined in the media by enzyme-linked immunosorbent assay. Gene expression in tendon tissue for collagen type I and III (COL1A1 and COL3A1, respectively), matrix metalloproteinase-3 and -13 (MMP-3 and MMP-13, respectively), cartilage oligomeric matrix protein (COMP), and IL-1β was determined. Data were divided into 3 groups of lrPRP based on the ratio of platelets:leukocytes and evaluated to determine the effect of platelet concentration. Complete blood counts verified leukocyte reduction and platelet enrichment in all PRP preparations. In the lrPRP preparation, the anabolic growth factors PDGF-BB and TGF-β1 were increased with increasing platelet concentrations, and the catabolic cytokine IL-1β was decreased with increasing platelet concentrations. Increasing the platelet concentration resulted in a significant reduction in COL1A1 and COL3A1 synthesis in tendons. Increasing the platelet concentration within lrPRP preparations results in the delivery of more anabolic growth factors and less proinflammatory cytokines, but the biological effect on tendons is diminished metabolism as indicated by a decrease in the synthesis of both COL1A1 and COL3A1. Together, this information suggests that

  9. Survival of density subpopulations of rabbit platelets: use of 51Cr-or 111In-labeled platelets to measure survival of least dense and most dense platelets concurrently

    International Nuclear Information System (INIS)

    Rand, M.L.; Packham, M.A.; Mustard, J.F.

    1983-01-01

    The origin of the density heterogeneity of platelets was studied by measuring the survival of density subpopulations of rabbit platelets separated by discontinuous Stractan density gradient centrifugation. When a total population of 51 Cr-labelled platelets was injected into recipient rabbits, the relative specific radioactivity of the most dense platelets decreased rapidly. In contrast, that of the least dense platelets had not changed 24 hr after injection, and then decreased slowly. To distinguish between the possibilities that most dense platelets are cleared from the circulation more quickly than least dense platelets or that platelets decrease in density as they age in the circulation, the concurrent survival of least dense and most dense platelets, labelled with either 51 Cr or 111 In-labelled total platelet populations, determined concurrently in the same rabbits, are identical, calculated from 1 hr values as 100%. However, the 1-hr recovery of 111 In-labelled platelets was slightly but significantly less than that of 51 Cr-labelled platelets. Therefore, researchers studied the survival of 51 Cr-labelled least dense and 111 In-labelled most dense platelets as well as that of 111 In-labelled least dense and 51 Cr-labelled most dense platelets. Mean 1-hr recovery of least dense platelets, labelled with either isotope (78% +/- 7%, SD) was similar to that of most dense platelets, labelled with either isotope (77% +/- 8%; SD). Mean survival of least dense platelets was 47.3 +/- 18.7 hr (SD), which was significantly less than that of most dense platelets (76.1 +/- 21.6 hr; SD) (p less than 0.0025). These results indicate that platelets decrease in buoyant density as they age in the circulation and that most dense platelets are enriched in young platelets, and least dense in old

  10. Thromboelastometric and platelet responses to silk biomaterials.

    Science.gov (United States)

    Kundu, Banani; Schlimp, Christoph J; Nürnberger, Sylvia; Redl, Heinz; Kundu, S C

    2014-05-13

    Silkworm's silk is natural biopolymer with unique properties including mechanical robustness, all aqueous base processing and ease in fabrication into different multifunctional templates. Additionally, the nonmulberry silks have cell adhesion promoting tri-peptide (RGD) sequences, which make it an immensely potential platform for regenerative medicine. The compatibility of nonmulberry silk with human blood is still elusive; thereby, restricts its further application as implants. The present study, therefore, evaluate the haematocompatibility of silk biomaterials in terms of platelet interaction after exposure to nonmulberry silk of Antheraea mylitta using thromboelastometry (ROTEM). The mulberry silk of Bombyx mori and clinically used Uni-Graft W biomaterial serve as references. Shortened clotting time, clot formation times as well as enhanced clot strength indicate the platelet mediated activation of blood coagulation cascade by tested biomaterials; which is comparable to controls.

  11. Novel approaches for diagnosing inherited platelet disorders.

    Science.gov (United States)

    Bastida Bermejo, José María; Hernández-Rivas, Jesús María; González-Porras, José Ramón

    2017-01-20

    Inherited platelet disorders diagnosis is based on the clinical history and bleeding assessment tools. The laboratory functional assays as well as the molecular test to identify the pathogenic genetic variant are essential to confirm the accurate diagnosis of these disorders. Nowadays, the main challenges to developing a new diagnostic system are involved in reducing the samples' volume, and faster and more helpful analysis. Moreover, there are no widely available and standardised global tests. High throughput genetic testing such as next-generation sequencing has revolutionised DNA sequencing technologies as it allows the simultaneous and faster investigation of multiple genes at a manageable cost. This technology has improved the molecular characterisation of inherited platelet disorders and has been implemented in the research studies and the clinical routine practice. Copyright © 2016 Elsevier España, S.L.U. All rights reserved.

  12. Platelet Rich Plasma and Knee Surgery

    Directory of Open Access Journals (Sweden)

    Mikel Sánchez

    2014-01-01

    Full Text Available In orthopaedic surgery and sports medicine, the knee joint has traditionally been considered the workhorse. The reconstruction of every damaged element in this joint is crucial in achieving the surgeon’s goal to restore the knee function and prevent degeneration towards osteoarthritis. In the last fifteen years, the field of regenerative medicine is witnessing a boost of autologous blood-derived platelet rich plasma products (PRPs application to effectively mimic and accelerate the tissue healing process. The scientific rationale behind PRPs is the delivery of growth factors, cytokines, and adhesive proteins present in platelets and plasma, as well as other biologically active proteins conveyed by the plasma such as fibrinogen, prothrombin, and fibronectin; with this biological engineering approach, new perspectives in knee surgery were opened. This work describes the use of PRP to construct and repair every single anatomical structure involved in knee surgery, detailing the process conducted in ligament, meniscal, and chondral surgery.

  13. Platelet microvesicles in health and disease.

    Science.gov (United States)

    Melki, Imene; Tessandier, Nicolas; Zufferey, Anne; Boilard, Eric

    2017-05-01

    Interest in cell-derived extracellular vesicles and their physiological and pathological implications is constantly growing. Microvesicles, also known as microparticles, are small extracellular vesicles released by cells in response to activation or apoptosis. Among the different microvesicles present in the blood of healthy individuals, platelet-derived microvesicles (PMVs) are the most abundant. Their characterization has revealed a heterogeneous cargo that includes a set of adhesion molecules. Similarly to platelets, PMVs are also involved in thrombosis through support of the coagulation cascade. The levels of circulatory PMVs are altered during several disease manifestations such as coagulation disorders, rheumatoid arthritis, systemic lupus erythematosus, cancers, cardiovascular diseases, and infections, pointing to their potential contribution to disease and their development as a biomarker. This review highlights recent findings in the field of PMV research and addresses their contribution to both healthy and diseased states.

  14. Metabolomic analysis of platelets during storage

    DEFF Research Database (Denmark)

    Paglia, Giuseppe; Sigurjónsson, Ólafur E; Rolfsson, Óttar

    2015-01-01

    BACKGROUND: Platelet concentrates (PCs) can be prepared using three methods: platelet (PLT)-rich plasma, apheresis, and buffy coat. The aim of this study was to obtain a comprehensive data set that describes metabolism of buffy coat-derived PLTs during storage and to compare it with a previously...... published parallel data set obtained for apheresis-derived PLTs. STUDY DESIGN AND METHODS: During storage we measured more than 150 variables in 8 PLT units, prepared by the buffy coat method. Samples were collected at seven different time points resulting in a data set containing more than 8000...... after their collection. The transition was evident in PLT produced by both production methods. Apheresis-derived PLTs showed a clearer phenotype of PLT activation during early days of storage. The activated phenotype of apheresis PLTs was accompanied by a higher metabolic activity, especially related...

  15. Platelet factor XIII increases the fibrinolytic resistance of platelet-rich clots by accelerating the crosslinking of alpha 2-antiplasmin to fibrin

    Science.gov (United States)

    Reed, G. L.; Matsueda, G. R.; Haber, E.

    1992-01-01

    Platelet clots resist fibrinolysis by plasminogen activators. We hypothesized that platelet factor XIII may enhance the fibrinolytic resistance of platelet-rich clots by catalyzing the crosslinking of alpha 2-antiplasmin (alpha 2AP) to fibrin. Analysis of plasma clot structure by polyacrylamide gel electrophoresis and immunoblotting revealed accelerated alpha 2AP-fibrin crosslinking in platelet-rich compared with platelet-depleted plasma clots. A similar study of clots formed with purified fibrinogen (depleted of factor XIII activity), isolated platelets, and specific factor XIII inhibitors indicated that this accelerated crosslinking was due to the catalytic activity of platelet factor XIII. Moreover, when washed platelets were aggregated by thrombin, there was evidence of platelet factor XIII-mediated crosslinking between platelet alpha 2AP and platelet fibrin(ogen). Specific inhibition (by a monoclonal antibody) of the alpha 2AP associated with washed platelet aggregates accelerated the fibrinolysis of the platelet aggregate. Thus in platelet-rich plasma clots, and in thrombin-induced platelet aggregates, platelet factor XIII actively formed alpha 2AP-fibrin crosslinks, which appeared to enhance the resistance of platelet-rich clots to fibrinolysis.

  16. High pressure measurement and CPA equation of state for solubility of carbon dioxide and hydrogen sulfide in 1-butyl-3-methylimidazolium acetate

    International Nuclear Information System (INIS)

    Haghtalab, Ali; Kheiri, Alireza

    2015-01-01

    Highlights: • Solubility of carbon dioxide in pure [bmim][acetate] is measured. • Simultaneous solubility of CO 2 + H 2 S in [bmim][acetate] is measured. • Both physical and chemical models are applied to modelling the (acid gas + IL) systems. • The CPA EoS is used for phase equilibrium calculation. • A reaction thermodynamic equilibrium model is used in liquid phase. - Abstract: Removal of acid gases such as CO 2 and H 2 S from natural gas is essential for commercial, safety and environmental protection that demonstrate the importance of gas sweetening process. Ionic liquids (IL) have been highly demanded as a green solvent to remove acid gases from sour natural gas and capturing of CO 2 from flue gases. In this work, the solubility of CO 2 in 1-butyl-3-methylimidazolium acetate ([bmim][Ac]) is measured at temperatures (303.15, 328.15, 343.15) K and pressure range of (0.1 to 3.9) MPa. Moreover, the experiments are carried out for simultaneous measurements of (CO 2 + H 2 S) (70% + 30% on a mole basis) solubility in the same ionic liquid at T = (303.15, 323.15, 343.15) K and a pressure range of (0.1 to 2.2) MPa. To model the solubility of acid gases in IL, both physical and chemical equilibria are applied so that the (vapour + liquid) equilibrium calculation is carried out through Cubic-Plus-Association (CPA) EoS. The reaction equilibrium thermodynamic model is used in liquid phase so that the chemical reaction is taking place between IL and acid gasses. The Henry’s and reaction equilibrium constants are obtained though optimization of the solubility data. Using CPA EOS, the pure parameters of [bmim][acetate] are optimised and consequently using these parameters, gas partial pressure calculation is performed for the (CO 2 + IL) and (CO 2 + H 2 S + IL) systems. For the (CO 2 + IL) system, the percent average absolute deviation (AAD%) of 4.83 is resulted and for the (H 2 S + CO 2 + IL) system the values of 18.8 and 13.7 are obtained for H 2 S and CO 2

  17. Inhibition of platelet aggregation and in vitro free radical scavenging activity of dried fruiting bodies of Pleurotus eous.

    Science.gov (United States)

    Suseem, S R; Saral, Mary

    2015-07-01

    To evaluate the ethyl acetate, methanol and aqueous extracts of dried fruiting bodies of Pleurotus eous for its anti-platelet activity on human volunteer's blood. And also to analyze the free radical scavenging property of the extracts of P.eous by using various in vitro models. Anti-platelet activity of dried fruiting bodies of P.eous was evaluated by in vitro model using blood platelets. Inhibition of platelet aggregation was monitored after pre-incubation of platelets with the crude extracts of mushroom P.eous. Antioxidant activities of extracts of P.eous were evaluated by different in vitro experiments, namely, 1, 1-diphenyl-2-picryl hydrazyl (DPPH), superoxide, hydroxyl radical and lipid peroxide radical models. Crude extracts of mushroom P.eous inhibited platelet aggregation dose-dependently which was induced by adenosine diphosphate (ADP). At a maximum concentration of 10 mg/mL, methanol extract effected 64.02% inhibition of lipid per-oxidation and 50.12% scavenging effect on superoxide anion radical. Aqueous extract of P.eous have shown 69.43% chelating ability on ferrous ions, 24.27% scavenging effect on hydroxyl radical and 49.57% scavenging effect on DPPH radical at 10 mg/mL. Increasing concentrations of the extract were found to cause progressively decreasing of the intensity of absorbance. Anti-platelet effects could be related in part to the polyphenolic compounds present in the extracts. Antioxidant activity results indicated the free radical scavenging property of the extracts of P.eous which might be due to the high content of phenolic compounds and flavonoids.

  18. Comparison of platelet counts by sysmex XE 2100 and LH-750 with the international flow reference method in thrombocytopenic patients

    Directory of Open Access Journals (Sweden)

    Tina Dadu

    2013-01-01

    Full Text Available Background: There are several methods for counting platelets, of which the international flow reference method (IRM is considered to be the gold standard. We compared the platelet count given by this method to the count given by automated analyzers using other methods, such as optical fluorescence and impedance. Aims: The aim of this study is to compare the platelet counts obtained by Sysmex XE 2100 by Impedance (Sysmex-I, optical florescence (Sysmex-O and reported (Sysmex-R based on the switching algorithm and LH-750 by Impedance (LH-750 with the IRM in thrombocytopenic blood samples. To calculate the sensitivity, specificity, positive predictive value (PPV and negative predictive value (NPV of various technologies at the clinically relevant transfusion thresholds of 10 × 10 9 /l and 20 × 10 9 /l. Materials and Methods: A total of 118 blood samples with platelet count of <50 × 10 9 /l were selected for the study. Platelet counts of all samples were analyzed by all methods using the Sysmex analyzer, LH-750 and IRM in parallel within 6 h of collection. Statistical Analysis Used: Pearson correlation, bland Altman analysis, sensitivity and specificity, PPV and NPV. Results and Conclusions: Sysmex-R had the least Bias and 95% limits of agreement (95%LA range and thus correlated best with IRM values. LH-750 had a higher Bias compared to Sysmex-O and Sysmex-R, but a strikingly similar 95% LA ensures similar results in all three methods. In fact, in the oncology subset, it had the narrowest 95% LA, which made it the best performer in this subgroup. Of the three Sysmex results, Sysmex-I had the highest bias, widest 95% LA and highest potential risk of over transfusion. Hence, Sysmex-R and LH-750 were found to be reliable tools for estimation of platelet count in thrombocytopenic patients.

  19. Kaempferol inhibits thrombosis and platelet activation.

    Science.gov (United States)

    Choi, Jun-Hui; Park, Se-Eun; Kim, Sung-Jun; Kim, Seung

    2015-08-01

    The objectives of the present study were to investigate whether kaempferol affects pro-coagulant proteinase activity, fibrin clot formation, blood clot and thrombin (or collagen/epinephrine)-stimulated platelet activation, thrombosis, and coagulation in ICR (Imprinting Control Region) mice and SD (Sprague-Dawley) rats. Kaempferol significantly inhibited the enzymatic activities of thrombin and FXa by 68 ± 1.6% and 52 ± 2.4%, respectively. Kaempferol also inhibited fibrin polymer formation in turbidity. Microscopic analysis was performed using a fluorescent conjugate. Kaempferol completely attenuated phosphorylation of extracellular signal-regulated kinase (ERK) 1/2, p38, c-Jun N-terminal kinase (JNK) 1/2, and phosphoinositide 3-kinase (PI3K)/PKB (AKT) in thrombin-stimulated platelets and delayed aggregation time (clotting) by 34.6% in an assay of collagen/epinephrine-stimulated platelet activation. Moreover, kaempferol protected against thrombosis development in 3 animal models, including collagen/epinephrine- and thrombin-induced acute thromboembolism models and an FeCl3-induced carotid arterial thrombus model. The ex vivo anticoagulant effect of kaempferol was further confirmed in ICR mice. This study demonstrated that kaempferol may be clinically useful due to its ability to reduce or prevent thrombotic challenge. Copyright © 2015 Elsevier B.V. and Société Française de Biochimie et Biologie Moléculaire (SFBBM). All rights reserved.

  20. Extraction spectrophotometric analyzer

    International Nuclear Information System (INIS)

    Batik, J.; Vitha, F.

    1985-01-01

    Automation is discussed of extraction spectrophotometric determination of uranium in a solution. Uranium is extracted from accompanying elements in an HCl medium with a solution of tributyl phosphate in benzene. The determination is performed by measuring absorbance at 655 nm in a single-phase ethanol-water-benzene-tributyl phosphate medium. The design is described of an analyzer consisting of an analytical unit and a control unit. The analyzer performance promises increased productivity of labour, improved operating and hygiene conditions, and mainly more accurate results of analyses. (J.C.)

  1. Platelet function testing: methods of assessment and clinical utility.

    LENUS (Irish Health Repository)

    Mylotte, Darren

    2012-02-01

    Platelets play a central role in the regulation of both thrombosis and haemostasis yet tests of platelet function have, until recently, been exclusively used in the diagnosis and management of bleeding disorders. Recent advances have demonstrated the clinical utility of platelet function testing in patients with cardiovascular disease. The ex vivo measurement of response to antiplatelet therapies (aspirin and clopidogrel), by an ever-increasing array of platelet function tests, is with some assays, predictive of adverse clinical events and thus, represents an emerging area of interest for both the clinician and basic scientist. This review article will describe the advantages and disadvantages of the currently available methods of measuring platelet function and discuss both the limitations and emerging data supporting the role of platelet function studies in clinical practice.

  2. Platelet function testing: methods of assessment and clinical utility.

    LENUS (Irish Health Repository)

    Mylotte, Darren

    2011-01-01

    Platelets play a central role in the regulation of both thrombosis and haemostasis yet tests of platelet function have, until recently, been exclusively used in the diagnosis and management of bleeding disorders. Recent advances have demonstrated the clinical utility of platelet function testing in patients with cardiovascular disease. The ex vivo measurement of response to antiplatelet therapies (aspirin and clopidogrel), by an ever-increasing array of platelet function tests, is with some assays, predictive of adverse clinical events and thus, represents an emerging area of interest for both the clinician and basic scientist. This review article will describe the advantages and disadvantages of the currently available methods of measuring platelet function and discuss both the limitations and emerging data supporting the role of platelet function studies in clinical practice.

  3. Indium-111 tropolone, a new tracer for platelet labeling

    International Nuclear Information System (INIS)

    Dewanjee, M.K.; Rao, S.A.; Rosemark, J.A.; Chowdhury, S.; Didisheim, P.

    1982-01-01

    Platelets have been labeled with a new neutral, lipid-soluble metal complex of indium 111 ( 111 In) and tropolone. Unlike oxine, which is soluble in ethyl alcohol, tropolone is soluble in isotonic saline. Platelet labeling with 111 In tropolone can be performed in both acid-citrate-dextrose (ACD) plasma and ACD saline within two hours. Labeling efficiency has been 80% to 90%. 111 In tropolone in ACD saline and ACD plasma at tropolone concentrations of 5 and 10 micrograms/ml, respectively, and incubation of the platelets with the tracer at room temperature for 20 minutes were optimal conditions for labeling. The authors have developed an ACD-saline kit for convenient preparation of 111 In-labeled platelets. No adverse effect of 111 In tropolone on platelets has been observed in studies of biodistribution, recovery, and survival of platelets in rabbits and dogs

  4. Indium-111 tropolone, a new tracer for platelet labeling

    International Nuclear Information System (INIS)

    Dewanjee, M.K.; Rao, S.A.; Rosemark, J.A.; Chowdhury, S.; Didisheim, P.

    1982-01-01

    Platelets have been labeled with a new neutral, lipid-soluble metal complex of indium 111 ( 111 In) and tropolone. Unlike oxine, which is soluble in ethyl alcohol, tropolone is soluble in isotonic saline. Platelet labeling with 111 In tropolone can be performed in both acid-citrate-dextrose (ACD) plasma and ACD saline within two hours. Labeling efficiency has been 80% to 90%. 111 In tropolone in ACD saline and ACD plasma at tropolone concentrations of 5 to 10 μg/ml, respectively, and incubation of the platelets with the tracer at room temperature for 20 minutes were optimal conditions for labeling. The authors have developed an ACD-saline kit for convenient preparation of 111 In-labeled platelets. No adverse effect of 111 In tropolone on platelets has been observed in studies of biodistribution, recovery, and survival of platelets in rabbits and dogs

  5. Feasibility of Using Multilayer Platelets as Toughening Agents

    Directory of Open Access Journals (Sweden)

    Yuan-Liang Chin

    2009-12-01

    Full Text Available It is known that the toughness of brittle ceramics can be improved significantly with the addition of hard platelets. In the present study, platelet-shape multilayer ceramic laminates are utilized as a toughening agent for alumina ceramics. They are prepared by laminating the BaTiO3-based ceramic tapes. Although the elastic modulus of the BaTiO3-based platelets is lower than that of the alumina matrix, and the platelets are also reactive to alumina at elevated temperatures, the weak platelets are found to exhibit the ability to deflect major matrix cracks by forming a large number of microcrack branches within the platelets, thus achieving the desired toughening effect.

  6. Platelet indices in dogs with Babesia rossi infection

    DEFF Research Database (Denmark)

    Goddard, Amelia; Leisewitz, Andrew L; Kristensen, Annemarie Thuri

    2015-01-01

    BACKGROUND: Thrombocytopenia without clinical bleeding is a consistent finding in virulent canine babesiosis. OBJECTIVES: The purpose of the study was to investigate the platelet index phenotype in Babesia rossi-infected dogs and the association with disease outcome. We hypothesized that an incre......BACKGROUND: Thrombocytopenia without clinical bleeding is a consistent finding in virulent canine babesiosis. OBJECTIVES: The purpose of the study was to investigate the platelet index phenotype in Babesia rossi-infected dogs and the association with disease outcome. We hypothesized...... that an increased proportion of large, activated platelets would be present. METHODS: Ninety-six infected and 15 control dogs were included. Babesia-infected dogs were further divided into survivors and nonsurvivors. Platelet count, mean platelet volume (MPV), platelet volume distribution width (PDW), plateletcrit...

  7. Platelet concentrates: Bioengineering dentistry′s regenerative dreams

    Directory of Open Access Journals (Sweden)

    Sushma Naag

    2015-01-01

    Full Text Available Technological advances in the fields of medicine and allied sciences had given much needed momentum into the field of molecular biology and regenerative medicine. They indeed provided a boost to innovate new yields for both hard tissue and soft tissue regeneration in dentistry. One among them is the use of platelet concentrates (platelet rich plasma [PRP], platelet rich fibrin [PRF]. Autologous concentrate of blood platelets with a suspension of growth factors offers an enhanced healing of hard and soft tissues. It is an auxiliary benefit for an operator to be aware of platelet concentrates and its healing properties for delivering unsurpassed oral health care to patients. The current article outlines the principles, objectives and clinical insight to the regenerative potential of platelet concentrates in various fields of dentistry. The search words of the PubMed data base were PRF and other permutations of keywords such as "PRP dentistry", PRF dentistry, PRF regenerative dentistry.

  8. Entrapment of platelets in the penis during and after erection

    International Nuclear Information System (INIS)

    Bornman, M.S.; Du Plessis, D.J.; Dormehl, I.C.; Du Plessis, M.; Jacobs, D.J.; Maree, M.

    1986-01-01

    Because of the development of hypercoagulability and the deposition of fibrin in the penis during erection a study of the possible role of platelets in this process was undertaken. Platelets response was studied in 9 adult chacma baboons (Papio ursinus) using autologous in vitro indium-111-labelled platelets and sequential scintigraphy of the penis during erection. The blood pooling pattern was obtained using in vivo technetium-99m-labelled red cells in a similar investigation. A statistically significant retention of platelets occured during and after erection, wich could not be attributed to blood pooling (P < 0,05). Entrapment of platelets could lead to enhanced activation, and might play a significant role in hypercoagulability and fibrin deposition during erection. Therefore platelets could be an important factor in the pathogenesis of ageing impotence

  9. Immature platelet fraction in bacterial sepsis severity assessment

    Science.gov (United States)

    Djuang, M. H.; Ginting, F.; Hariman, H.

    2018-03-01

    Sepsis is an infection-induced syndrome, mostly caused by bacteria, of organ dysfunctions that caused by host response dysregulations. One of the simplest sepsis-indicator is platelet and its indexes. A new platelet parameter called immature platelet count (IPF) became theinterest in this study. The study aims to see whether IPF could assess sepsis severity by procalcitonin (PCT).Sixty-four of seventy-one patients with increased PCT were included in this cross-sectional study and separated into three groups based on their PCT levels. IPF showed no significance among the three groups (p-value>0.05) while platelet count was significant (p-valuesepsis severity based on PCT showed larger platelet count, as the result of platelet destructions caused by pro-inflammatory cytokines and endotoxins.

  10. Favorable effects of berry consumption on platelet function, blood pressure, and HDL cholesterol.

    Science.gov (United States)

    Erlund, Iris; Koli, Raika; Alfthan, Georg; Marniemi, Jukka; Puukka, Pauli; Mustonen, Pirjo; Mattila, Pirjo; Jula, Antti

    2008-02-01

    Berries are a particularly rich source of polyphenols. They also contain other bioactive substances, such as vitamin C. Previous studies indicated that the consumption of polyphenol-rich foods (eg, cocoa, tea, and red wine) may induce beneficial changes in pathways related to cardiovascular health. Whether the consumption of berries has similar effects is unknown. We aimed to investigate the effects of berry consumption on hemostatic function, serum lipids, and blood pressure (BP). Middle-aged unmedicated subjects (n = 72) with cardiovascular risk factors consumed moderate amounts of berry or control products for 8 wk in a single-blind, randomized, placebo-controlled intervention trial. Berry consumption inhibited platelet function as measured with a platelet function analyzer (using collagen and ADP as platelet activator) [changes: 11% and -1.4% in the berry and control groups, respectively; P = 0.018, analysis of covariance (ANCOVA)]. Plasma biomarkers of platelet activation, coagulation, and fibrinolysis did not change during the intervention. Serum HDL-cholesterol concentrations increased significantly more (P = 0.006, ANCOVA) in the berry than in the control group (5.2% and 0.6%, respectively), but total cholesterol and triacylglycerol remained unchanged. Systolic BP decreased significantly (P = 0.050, ANCOVA); the decrease mostly occurred in subjects with high baseline BP (7.3 mm Hg in highest tertile; P = 0.024, ANCOVA). Polyphenol and vitamin C concentrations in plasma increased, whereas other nutritional biomarkers (ie, folate, tocopherols, sodium, and potassium) were unaffected. The consumption of moderate amounts of berries resulted in favorable changes in platelet function, HDL cholesterol, and BP. The results indicate that regular consumption of berries may play a role in the prevention of cardiovascular disease.

  11. Micronutrients attenuate progression of prostate cancer by elevating the endogenous inhibitor of angiogenesis, Platelet Factor-4

    International Nuclear Information System (INIS)

    Cervi, David; Pak, Brian; Venier, Natalie A; Sugar, Linda M; Nam, Robert K; Fleshner, Neil E; Klotz, Laurence H; Venkateswaran, Vasundara

    2010-01-01

    Longstanding evidence implicates an inadequate diet as a key factor in the onset and progression of prostate cancer. The purpose herein was to discover, validate and characterize functional biomarkers of dietary supplementation capable of suppressing the course of prostate cancer in vivo. The Lady transgenic mouse model that spontaneously develops prostate cancer received a diet supplemented with a micronutrient cocktail of vitamin E, selenium and lycopene ad libitum. A proteomic analysis was conducted to screen for serum biomarkers of this dietary supplementation. Candidate peptides were validated and identified by sequencing and analyzed for their presence within the prostates of all mice by immunohistochemistry. Dietary supplementation with the combined micronutrients significantly induced the expression of the megakaryocyte-specific inhibitor of angiogenesis, platelet factor-4 (P = 0.0025). This observation was made predominantly in mice lacking tumors and any manifestations associated with progressive disease beyond 37 weeks of life, at which time no survivors remained in the control group (P < 0.0001). While prostates of mice receiving standard chow were enlarged and burdened with poorly differentiated carcinoma, those of mice on the supplemented diet appeared normal. Immunohistochemical analysis revealed marked amplifications of both platelet binding and platelet factor-4 within the blood vessels of prostates from mice receiving micronutrients only. We present unprecedented data whereby these combined micronutrients effectively promotes tumor dormancy in early prostate cancer, following initiation mutations that may drive the angiogenesis-dependent response of the tumor, by inducing platelet factor-4 expression and concentrating it at the tumor endothelium through enhanced platelet binding

  12. Americal options analyzed differently

    NARCIS (Netherlands)

    Nieuwenhuis, J.W.

    2003-01-01

    In this note we analyze in a discrete-time context and with a finite outcome space American options starting with the idea that every tradable should be a martingale under a certain measure. We believe that in this way American options become more understandable to people with a good working

  13. Analyzing Political Television Advertisements.

    Science.gov (United States)

    Burson, George

    1992-01-01

    Presents a lesson plan to help students understand that political advertisements often mislead, lie, or appeal to emotion. Suggests that the lesson will enable students to examine political advertisements analytically. Includes a worksheet to be used by students to analyze individual political advertisements. (DK)

  14. Centrifugal analyzer development

    International Nuclear Information System (INIS)

    Burtis, C.A.; Bauer, M.L.; Bostick, W.D.

    1976-01-01

    The development of the centrifuge fast analyzer (CFA) is reviewed. The development of a miniature CFA with computer data analysis is reported and applications for automated diagnostic chemical and hematological assays are discussed. A portable CFA system with microprocessor was adapted for field assays of air and water samples for environmental pollutants, including ammonia, nitrates, nitrites, phosphates, sulfates, and silica. 83 references

  15. Alterations on the morphology, nitric oxide synthesis and activity of platelets reproduced in rats as possible biomarkers for depression are reversed by fluoxetine.

    Science.gov (United States)

    González-Trujano, María Eva; Alvarado-Vásquez, Noé; Mendoza-Sotelo, José; López, Guadalupe; Estrada-Camarena, Erika; Martínez-Mota, Lucia; Moreno, Julia

    2012-08-01

    Biochemical markers associated with the prognosis of depression in humans are being described in the literature, whereas experimental studies in animal models in search for antidepressant strategies are lacking. The aim of this study was to evaluate platelet morphology, platelet activity and nitric oxide (NO) synthesis as possible biomarkers of depressive-like behavior by using FST alone and in the presence of fluoxetine. Naïve rats were compared to those receiving vehicle or fluoxetine at 10mg/kg i.p. in acute, subchronic and chronic administration in the FST. After behavioral assessment, platelets were isolated from blood samples and analyzed by flow cytometry to determine the platelet mitochondrial membrane potential and NO synthesis. In addition, HPLC and electron microscopy were used to examine 5-HT and tryptophan levels and morphology of platelets, respectively. Rats receiving vehicle and exposed to FST showed depressive-like behavior at all the times tested; after chronic FST rats showed a similar pattern of alteration in platelet morphology and in the studied as possible biochemical markers as those previously recognized in depressive humans. Depressive-like behavior in rats exposed to FST was prevented in the presence of fluoxetine administration at all the times tested and associated with the prevention of alterations in platelet morphology, platelet activity and NO synthesis, and/or in 5-HT concentrations. The results of the present study suggest that platelet function and morphology might be relevant markers for the prognosis of depression and the search for functional treatments. Besides, the relevance of FST as model to study this psychiatric illness is reinforced. Copyright © 2012 Elsevier Inc. All rights reserved.

  16. Platelet survival in idiopathic thrombocytopenic purpura and response to splenectomy

    International Nuclear Information System (INIS)

    Monteiro, M.E.; Verhaeghe, R.; Devos, P.

    Platelet survival combined with surface counting was performed in 9 patients with idiopathic thrombocytopenic purpura, resistent to steroid therapy. All patients had a markedly enhanced platelet turnover, five of them showed an augmented trapping of radioactivity over the spleen compared to liver and heart. These five patients underwent splenectomy: the platelet count increased in all of them but this increase was not always sustained. (Author) [pt

  17. Platelets and infections—complex interactions with bacteria

    Directory of Open Access Journals (Sweden)

    Hind eHAMZEH-COGNASSE

    2015-02-01

    Full Text Available Platelets can be considered sentinels of vascular system due to their high number in the circulation and to the range of functional immunoreceptors they express. Platelets express a wide range of potential bacterial receptors, including complement receptors, FcγRII, Toll-Like Receptors but also integrins conventionally described in the hemostatic response, such as GPIIb-IIIa or GPIb. Bacteria bind these receptors either directly, or indirectly via fibrinogen, fibronectin, the first complement C1q, the von Willebrand Factor, etc. The fate of platelet bound bacteria is questioned. Several studies reported the ability of activated platelets to internalize bacteria such as Staphylococcus aureus or Porphyromonas gingivalis, though there is no clue on what happens thereafter. Are they sheltered from the immune system in the cytoplasm of platelets or are they lysed? Indeed, while the presence of phagolysosome has not been demonstrated in platelets, they contain antimicrobial peptides that were shown to be efficient on S. aureus. Besides, the fact that bacteria can bind to platelets via receptors involved in hemostasis suggests that they may induce aggregation; this has indeed been described for Streptococcus sanguinis, S. epidermidis or C. pneumoniae. On the other hand, platelets are able to display an inflammatory response to an infectious triggering. We, and others, have shown that platelet release soluble immunomodulatory factors upon stimulation by bacterial components. Moreover, interactions between bacteria and platelets are not limited to only these two partners. Indeed, platelets are also essential for the formation of Neutrophil Extracellular Traps by neutrophils, resulting in bacterial clearance by trapping bacteria and concentrating antibacterial factors but in enhancing thrombosis. In conclusion, the platelet-bacteria interplay is a complex game; its fine analysis is complicated by the fact that the inflammatory component adds to the

  18. Imaging thrombus with radiolabelled monoclonal antibody to platelets

    International Nuclear Information System (INIS)

    Loutfi, I.; Peters, A.M.; Lavender, J.P.; Epenetos, A.A.

    1988-01-01

    Indium-111-hydroxyquinoline labelled platelets, though useful in the detection of thrombus, have not gained widespread use owing to the time and technical skill required for their preparation. A study was therefore conducted evaluating a new method of imaging thrombus with platelets radiolabelled with a 111 In labelled monoclonal antibody, P 256 , directed to the platelet surface glycoprotein complex IIb/IIIa. When the number of receptors occupied by P 256 was less than 3% of the total available on the platelet surface platelet function, as assessed by platelet aggregometry, was undisturbed. P 256 was radiolabelled with 111 In using diethylenetriaminepenta-acetic acid, which achieved a specific activity of 185 MBq (5 mCi)/mg. No impairment of immunoreactivity was detected at this specific activity. Platelets were labelled with radiolabelled monoclonal antibody in vitro in two patients at a receptor occupancy of 6% and in vivo - that is, by direct intravenous injection of P 256 - in six patients at a receptor occupancy of 1%. In vivo recovery and biodistribution kinetics suggested that after in vitro labelling platelets were minimally activated. The 111 In kinetics recorded after intravenous P 256 suggested rapid and efficient radiolabelling of platelets and gave no indication of platelet activation. Of the six patients who received intravenous P 256 , three had documented thrombus, tow of whom gave positive results on P 256 platelet scintigraphy. The third subject had chromic deep venous thrombosis and was scintigraphically negative. Imaging thrombus using a radiolabelled monoclonal antibody directed to platelets appears to offer great potential as a simple, non-invasive approach to the diagnosis of thrombosis. 3 refs. (Author)

  19. Platelet Rich Plasma- mechanism of action and clinical applications

    OpenAIRE

    Cristina N. Cozma; Laura Raducu; Cristian R. Jecan

    2016-01-01

    Platelet-rich plasma (PRP) is a blood-derived fraction containing high level of platelets, a high concentration of leukocytes and growth factors. PRP therapy has been growing as a viable treatment alternative for a number of clinical applications and has a potential benefit for use in wound healing. Nowadays platelet rich plasma is used in stimulating wound healing in skin and soft tissue ulcerations, accelerating wound healing in diabetic patients and facilitating bone proliferation in ortho...

  20. USE OF VITAL STAINING IN STORED HUMAN PLATELETS MORPHOFUNCTIONAL ANALYSIS

    Directory of Open Access Journals (Sweden)

    M. S. Makarov

    2014-01-01

    Full Text Available Apheresis and pooled platelet concentrates, stored at 22°C during 5 days, were studied with morho-functional platelet rate analysis, based on vital cell staining and registration with fluorescent microscope. It was revealed that apheresis and pooled PC had, on the average, normal values of morphological and functional parameters. On the other hand, both PC kept MFPR of cells only for 2 days storage. Longer PC storage caused the significant decay of morphological and functional platelet parameters.

  1. Platelets and hemophilia: A review of the literature.

    Science.gov (United States)

    Riedl, Julia; Ay, Cihan; Pabinger, Ingrid

    2017-07-01

    Hemophilia A and B are inherited bleeding disorders due to deficiencies of the clotting factors VIII and IX, respectively. The severity of the disease correlates with remaining factor levels, although individual differences in bleeding tendency are seen despite similar factor levels. While thrombin generation is severely impaired in persons with hemophilia, primary hemostasis, i.e. platelet function, has been generally considered to be normal. However, some studies reported prolonged bleeding times in hemophilia, suggesting that also primary hemostasis is affected. In several other studies different aspects of platelet function in hemophilia have been investigated in more detail and various alterations were discovered, such as increased platelet P-selectin expression, a lower number of procoagulant, so-called 'coated' platelets, lower aggregation upon co-incubation with tissue factor, or reduced platelet contractile forces during clot formation in comparison to healthy individuals. An influence of platelet function on clinical phenotype was suggested, which might contribute in part to variations in bleeding tendency in hemophilic patients with similar factor levels. However, the available evidence is currently limited and no clear correlations between platelet function parameters and clinical phenotypes have been demonstrated. The impact of alterations of platelet function in hemophilia remains to be better defined. Another interesting role of platelets in hemophilia has been reported recently by establishing a novel gene-therapeutic strategy using platelets as a delivery system for FVIII, showing promising results in animal models. This review gives an overview on the currently published literature on platelet function and the potential roles of platelets in hemophilia. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Quantification of platelets obtained by different centrifugation protocols in SHR rats.

    Science.gov (United States)

    Yazigi Junior, João Alberto; Dos Santos, João Baptista Gomes; Xavier, Bruno Rodrigues; Fernandes, Marcela; Valente, Sandra Gomes; Leite, Vilnei Mattiolli

    2015-01-01

    To quantify the platelet concentration in the blood of SHR rats, by means of different centrifugation protocols, and to evaluate what the most effective method for obtaining platelets is. We used 40 male rats of the isogenic SHR lineage. The animals were divided into three groups: control, using whole blood without centrifugation; single centrifugation, using whole blood subjected to a single centrifugation at 200 × g and 400 × g; and double centrifugation, using whole blood subjected one centrifugation at different rotations, followed by collection of whole plasma subjected to another centrifugation at different rotations: 200 × g + 200 × g; 200 × g + 400 × g; 200 × g + 800 × g; 400 × g + 400 × g; 400 × g + 800 × g. Samples of 3 ml of blood were drawn from each animal by means of cardiac puncture. The blood was stored in Vacutainer collection tubes containing 3.2% sodium citrate. The blood from the control group animals was analyzed without being subjected to centrifugation. After the blood from the other groups of animals had been subjected to centrifugation, the whole plasma was collected and subjected to platelet counting in the lower third of the sample. We obtained greatest platelet enrichment in the subgroup with two centrifugations comprising 400 × g for 10 min + 400 × g for 10 min, in which the mean platelet concentration was 11.30 times higher than that of the control group. It was possible to obtain a high platelet concentration using viable simple techniques, by means of centrifugation of whole blood and use of commonly used materials. The most effective method for obtaining platelet concentrate was found in samples subjected to two centrifugations.

  3. Mechanics of Platelet-Matrix Composites across Scales: Theory, Multiscale Modeling, and 3D Fabrication

    Science.gov (United States)

    Sakhavand, Navid

    Many natural and biomimetic composites - such as nacre, silk and clay-polymer - exhibit a remarkable balance of strength, toughness, and/or stiffness, which call for a universal measure to quantify this outstanding feature given the platelet-matrix structure and material characteristics of the constituents. Analogously, there is an urgent need to quantify the mechanics of emerging electronic and photonic systems such as stacked heterostructures, which are composed of strong in-plane bonding networks but weak interplanar bonding matrices. In this regard, development of a universal composition-structure-property map for natural platelet-matrix composites, and stacked heterostructures opens up new doors for designing materials with superior mechanical performance. In this dissertation, a multiscale bottom-up approach is adopted to analyze and predict the mechanical properties of platelet-matrix composites. Design guidelines are provided by developing universally valid (across different length scales) diagrams for science-based engineering of numerous natural and synthetic platelet-matrix composites and stacked heterostructures while significantly broadening the spectrum of strategies for fabricating new composites with specific and optimized mechanical properties. First, molecular dynamics simulations are utilized to unravel the fundamental underlying physics and chemistry of the binding nature at the atomic-level interface of organic-inorganic composites. Polymer-cementitious composites are considered as case studies to understand bonding mechanism at the nanoscale and open up new venues for potential mechanical enhancement at the macro-scale. Next, sophisticated mathematical derivations based on elasticity and plasticity theories are presented to describe pre-crack (intrinsic) mechanical performance of platelet-matrix composites at the microscale. These derivations lead to developing a unified framework to construct series of universal composition

  4. A comprehensive proteomics study on platelet concentrates: Platelet proteome, storage time and Mirasol pathogen reduction technology.

    Science.gov (United States)

    Salunkhe, Vishal; De Cuyper, Iris M; Papadopoulos, Petros; van der Meer, Pieter F; Daal, Brunette B; Villa-Fajardo, María; de Korte, Dirk; van den Berg, Timo K; Gutiérrez, Laura

    2018-03-19

    Platelet concentrates (PCs) represent a blood transfusion product with a major concern for safety as their storage temperature (20-24°C) allows bacterial growth, and their maximum storage time period (less than a week) precludes complete microbiological testing. Pathogen inactivation technologies (PITs) provide an additional layer of safety to the blood transfusion products from known and unknown pathogens such as bacteria, viruses, and parasites. In this context, PITs, such as Mirasol Pathogen Reduction Technology (PRT), have been developed and are implemented in many countries. However, several studies have shown in vitro that Mirasol PRT induces a certain level of platelet shape change, hyperactivation, basal degranulation, and increased oxidative damage during storage. It has been suggested that Mirasol PRT might accelerate what has been described as the platelet storage lesion (PSL), but supportive molecular signatures have not been obtained. We aimed at dissecting the influence of both variables, that is, Mirasol PRT and storage time, at the proteome level. We present comprehensive proteomics data analysis of Control PCs and PCs treated with Mirasol PRT at storage days 1, 2, 6, and 8. Our workflow was set to perform proteomics analysis using a gel-free and label-free quantification (LFQ) approach. Semi-quantification was based on LFQ signal intensities of identified proteins using MaxQuant/Perseus software platform. Data are available via ProteomeXchange with identifier PXD008119. We identified marginal differences between Mirasol PRT and Control PCs during storage. However, those significant changes at the proteome level were specifically related to the functional aspects previously described to affect platelets upon Mirasol PRT. In addition, the effect of Mirasol PRT on the platelet proteome appeared not to be exclusively due to an accelerated or enhanced PSL. In summary, semi-quantitative proteomics allows to discern between proteome changes due to

  5. Development of laser diode-pumped high average power solid-state laser for the pumping of Ti:sapphire CPA system

    Energy Technology Data Exchange (ETDEWEB)

    Maruyama, Yoichiro; Tei, Kazuyoku; Kato, Masaaki; Niwa, Yoshito; Harayama, Sayaka; Oba, Masaki; Matoba, Tohru; Arisawa, Takashi; Takuma, Hiroshi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1998-03-01

    Laser diode pumped all solid state, high repetition frequency (PRF) and high energy Nd:YAG laser using zigzag slab crystals has been developed for the pumping source of Ti:sapphire CPA system. The pumping laser installs two main amplifiers which compose ring type amplifier configuration. The maximum amplification gain of the amplifier system is 140 and the condition of saturated amplification is achieved with this high gain. The average power of fundamental laser radiation is 250 W at the PRF of 200 Hz and the pulse duration is around 20 ns. The average power of second harmonic is 105 W at the PRF of 170 Hz and the pulse duration is about 16 ns. The beam profile of the second harmonic is near top hat and will be suitable for the pumping of Ti:sapphire laser crystal. The wall plug efficiency of the laser is 2.0 %. (author)

  6. Liquid–liquid equilibria for reservoir fluids+monoethylene glycol and reservoir fluids+monoethylene glycol+water: Experimental measurements and modeling using the CPA EoS

    DEFF Research Database (Denmark)

    Frost, Michael; Kontogeorgis, Georgios; Stenby, Erling Halfdan

    2013-01-01

    for critical temperature, pressure and acentric factor.This work presents new phase equilibrium data for binary MEG/reservoir fluid and ternary MEG/water/reservoir fluid systems, where two reservoir fluids from Statoil operated fields are used. The solubility data are reported over a range of temperatures......The complex phase equilibrium between reservoir fluids and associating compounds like water and glycols has become more and more important as the increasing global energy demand pushes the oil industry to use advanced methods to increase oil recovery, such as increasing the use of various chemicals...... to ensure a constant and safe production. The CPA equation of state has been successfully applied in the past to well defined systems and gas condensates, containing associating compounds. It has also been extended to reservoir fluids in presence of water and polar chemicals using modified correlations...

  7. Liquid-liquid equilibria for binary and ternary systems containing glycols, aromatic hydrocarbons, and water: Experimental measurements and modeling with the CPA EoS

    DEFF Research Database (Denmark)

    Folas, Georgios; Kontogeorgis, Georgios; Michelsen, Michael Locht

    2006-01-01

    Liquid-liquid equilibrium data of four binary glycol + aromatic hydrocarbon systems and three ternary systems containing water have been measured at atmospheric pressure. The measured systems are monoethylene glycol (MEG) + benzene or toluene, triethylene glycol (TEG) + benzene or toluene, MEG...... + water + benzene, MEG + water + toluene, and TEG + water + toluene. The binary systems are correlated with the Cubic-Plus-Association (CPA) equation of state while the ternary systems are predicted from interaction parameters obtained from the binary systems. Very satisfactory liquid-liquid equilibrium...... correlations are obtained for the binary systems using temperature-independent interaction parameters, while adequate predictions are achieved for multicomponent water + glycol + aromatic hydrocarbons systems when accounting for the solvation between the aromatic hydrocarbons and glycols or water....

  8. Relationship between platelet phospholipid FA and mean platelet volume in healthy men.

    Science.gov (United States)

    Li, Duo; Turner, Alan; Sinclair, Andrew J

    2002-09-01

    Increased mean platelet volume (MPV) has been suggested as an independent risk factor for acute myocardial infarction and the increased reactivity of large platelets. The aim of this study was to investigate the correlation between platelet phospholipid (PL) PUFA composition and MPV in 139 free-living healthy men ages 20-55 yr (vegans, n = 18; ovolacto vegetarians, n = 43; moderate meat-eaters, n = 60; and high meateaters, n = 18). Each subject completed a semiquantitative Food Frequency Questionnaire and gave a blood sample. Platelet PL FA composition and MPV were determined by standard methods. MPV was significantly greater in the vegans than in the ovolacto vegetarian, moderate, or high meat-eater groups (P vegan and ovolacto vegetarian groups had significantly higher platelet PL 18:2n-6 and 22:4n-6, and lower 20:5n-3 and 22:6n-3 compared with the moderate and high meat-eater groups. The vegans demonstrated a significant reduction in 20:4n-6 and 22:5n-3 compared with the ovolacto vegetarian, high meat-eater, and moderate meat-eater groups. Bivariate analysis results showed that MPV was significantly positively correlated with platelet PL 18:2n-6 (P = 0.048) and negatively correlated with 20:3n-6 (P = 0.02), 20:5n-3 (P = 0.005), and 22:5n-3 (P< 0.0001), respectively. In a multiple linear regression analysis, after controlling for potential confounding factors such as dietary group, age, exercise, body mass index, and dietary polyunsaturated and saturated fat, cholesterol, carbohydrate, and fiber intake, the MPV was still strongly negatively correlated with platelet PL 20:3n-6 (P = 0.003) and 22:5n-3 (P = 0.001). The present data suggest that 22:5n-3 and 20:3n-6 may play a role in the structural function of the platelet membrane.

  9. Vapor-liquid, liquid-liquid and vapor-liquid-liquid equilibrium of binary and multicomponent systems with MEG modeling with the CPA EoS and an EoS/G(E) model

    DEFF Research Database (Denmark)

    Folas, Georgios; Kontogeorgis, Georgios; Michelsen, Michael Locht

    2006-01-01

    The cubic-plus-association (CPA) EoS is applied to multicomponent multiphase equilibria of systems containing MEG as a hydrate inhibitor. It is shown that the model provides very satisfactory prediction of the phase behavior for the systems tested. A more conventional engineering model for handling...

  10. Platelet adhesion studies on dipyridamole coated polyurethane surfaces

    Directory of Open Access Journals (Sweden)

    Aldenhoff Y. B.J.

    2003-06-01

    Full Text Available Surface modification of polyurethanes (PUs by covalent attachment of dipyridamole (Persantinregistered is known to reduce adherence of blood platelets upon exposure to human platelet rich plasma (PRP. This effect was investigated in further detail. First platelet adhesion under static conditions was studied with four different biomaterial surfaces: untreated PU, PU immobilised with conjugate molecule 1, PU immobilised with conjugate molecule 2, and PU immobilised with conjugate molecule 3. In PU immobilised with 1 dipyridamole is directly linked to the surface, in PU immobilised with 2 there is a short hydrophilic spacer chain in between the surface and the dipyridamole, while conjugate molecule 3 is merely the spacer chain. Scanning electron microscopy (SEM was used to characterise platelet adhesion from human PRP under static conditions, and fluorescence imaging microscopy was used to study platelet adhesion from whole blood under flow. SEM experiments encompassed both density measurements and analysis of the morphology of adherent platelets. In the static experiments the surface immobilised with 2 showed the lowest platelet adherence. No difference between the three modified surfaces emerged from the flow experiments. The surfaces were also incubated with washed blood platelets and labeled with Oregon-Green Annexin V. No capture of Oregon-Green Annexin V was seen, implying that the adhered platelets did not expose any phosphatidyl serine at their exteriour surface.

  11. Human plasma fibrinogen adsorption and platelet adhesion to polystyrene.

    Science.gov (United States)

    Tsai, W B; Grunkemeier, J M; Horbett, T A

    1999-02-01

    The purpose of this study was to further investigate the role of fibrinogen adsorbed from plasma in mediating platelet adhesion to polymeric biomaterials. Polystyrene was used as a model hydrophobic polymer; i.e., we expected that the role of fibrinogen in platelet adhesion to polystyrene would be representative of other hydrophobic polymers. Platelet adhesion was compared to both the amount and conformation of adsorbed fibrinogen. The strategy was to compare platelet adhesion to surfaces preadsorbed with normal, afibrinogenemic, and fibrinogen-replenished afibrinogenemic plasmas. Platelet adhesion was determined by the lactate dehydrogenase (LDH) method, which was found to be closely correlated with adhesion of 111In-labeled platelets. Fibrinogen adsorption from afibrinogenemic plasma to polystyrene (Immulon I(R)) was low and polystyrene preadsorbed with fibrinogen-replenished afibrinogenemic plasma. Addition of even small, subnormal concentrations of fibrinogen to afibrinogenemic plasma greatly increased platelet adhesion. In addition, surface-bound fibrinogen's ability to mediate platelet adhesion was different, depending on the plasma concentration from which fibrinogen was adsorbed. These differences correlated with changes in the binding of a monoclonal antibody that binds to the Aalpha chain RGDS (572-575), suggesting alteration in the conformation or orientation of the adsorbed fibrinogen. Platelet adhesion to polystyrene preadsorbed with blood plasma thus appears to be a strongly bivariate function of adsorbed fibrinogen, responsive to both low amounts and altered states of the adsorbed molecule. Copyright 1999 John Wiley & Sons, Inc.

  12. Enhancement by platelets of oxygen radical responses of human neutrophils

    Energy Technology Data Exchange (ETDEWEB)

    McCulloch, K.K.; Powell, J.; Johnson, K.J.; Ward, P.A.

    1986-03-01

    When human blood neutrophils were incubated with immune complexes (consisting of IgG antibody) in the presence of platelets, there was a 2 to 10 fold enhancement in the generation of O-/sub 2/ and H/sub 2/O/sub 2/. This enhancement phenomenon was proportional to the dose of immune complex added and the number of platelets present. The response was not agonist specific since similar enhancement also occurred with the following agonists: phorbol myristate acetate, opsonized zymosan particles and the chemotactic peptide N-formyl-met-leu-phe. The platelet related phenomenon of enhanced O-/sub 2/ generation could not be reproduced by the addition of serotonin, histamine or platelet-derived growth factor and was not affected by prior treatment of platelets with cyclooxygenase inhibitors (indomethacin, piroxicam) or lipoxygenase inhibitors (nafazatrom, BW755C or nordihydroguaiaretic acid). However, activation of platelets by thrombin caused release into the platelet supernatant fluid of a factor that, only in the presence of immune complexes, caused enhanced O-/sub 2/ responses to neutrophils. These data indicate that platelets potentiate oxygen radical responses of human neutrophils and suggest a mechanisms by which platelets may participate in tissue injury which is mediated by oxygen radical products from activated neutrophils.

  13. Enhancement by platelets of oxygen radical responses of human neutrophils

    International Nuclear Information System (INIS)

    McCulloch, K.K.; Powell, J.; Johnson, K.J.; Ward, P.A.

    1986-01-01

    When human blood neutrophils were incubated with immune complexes (consisting of IgG antibody) in the presence of platelets, there was a 2 to 10 fold enhancement in the generation of O- 2 and H 2 O 2 . This enhancement phenomenon was proportional to the dose of immune complex added and the number of platelets present. The response was not agonist specific since similar enhancement also occurred with the following agonists: phorbol myristate acetate, opsonized zymosan particles and the chemotactic peptide N-formyl-met-leu-phe. The platelet related phenomenon of enhanced O- 2 generation could not be reproduced by the addition of serotonin, histamine or platelet-derived growth factor and was not affected by prior treatment of platelets with cyclooxygenase inhibitors (indomethacin, piroxicam) or lipoxygenase inhibitors (nafazatrom, BW755C or nordihydroguaiaretic acid). However, activation of platelets by thrombin caused release into the platelet supernatant fluid of a factor that, only in the presence of immune complexes, caused enhanced O- 2 responses to neutrophils. These data indicate that platelets potentiate oxygen radical responses of human neutrophils and suggest a mechanisms by which platelets may participate in tissue injury which is mediated by oxygen radical products from activated neutrophils

  14. Imaging thrombus with radiolabelled monoclonal antibody to platelets

    Energy Technology Data Exchange (ETDEWEB)

    Peters, A.M.; Lavender, J.P.; Needham, S.G.; Loutfi, I.; Snook, D.; Epenetos, A.A.; Lumley, P.; Keery, R.J.; Hogg, N.

    1986-12-13

    A study was conducted evaluating a method of imaging thrombus with platelets radiolabelled with a /sup 111/In labelled monoclonal antibody, P256, directed to the platelet surface glycoprotein complex IIb/IIIa. when the number of receptors occupied by P256 was less than 3% of the total available on the platelet surface, platelet function was undisturbed. P256 was radiolabelled with /sup 111/In using diethylenetriaminepenta-acetic acid, which achieved a specific activity of 185 MBq (5 mCi)/mg. No impairment of immunoreactivity was detected at this specific activity. Platelets were labelled with radiolabelled monoclonal antibody in vitro in two patients at a receptor occupancy of 6% and in vivo in six patients at a receptor occupancy of 1%. In vivo recovery and biodistribution kinetics suggested that after in vitro labelling platelets were minimally activated. The /sup 111/In kinetics recorded after intravenous P256 suggested rapid and efficient radiolabelling of platelets and gave no indication of platelet activation. Of the six patients who received intravenous P256, three had documented thrombus, two of whom gave positive results on P256 platelet scintigraphy. The third had chronic deep venous thrombosis and was scintigraphically negative.

  15. Dark chocolate inhibits platelet aggregation in healthy volunteers.

    Science.gov (United States)

    Innes, Andrew J; Kennedy, Gwen; McLaren, Margaret; Bancroft, Anne J; Belch, Jill J F

    2003-08-01

    Cardiovascular disease is a leading cause of death in the UK. The flavonoids found in cocoa may produce a cardio-protective role for chocolate with a high cocoa content. Thirty healthy volunteers were randomised to receive 100 g of white, milk or dark chocolate, and assessments of platelet function were undertaken on venous blood samples before and after chocolate consumption. White and milk chocolate had no significant effect on platelets. However dark chocolate inhibited collagen-induced platelet aggregation in platelet rich plasma. In the future dark chocolate may have a role in prevention of cardiovascular and thromboembolic diseases.

  16. Evaluation of four methods for platelet compatibility testing

    International Nuclear Information System (INIS)

    McFarland, J.G.; Aster, R.H.

    1987-01-01

    Four platelet compatibility assays were performed on serum and platelet or lymphocyte samples from 38 closely HLA-matched donor/recipient pairs involved in 55 single-donor platelet transfusions. The 22 patients studied were refractory to transfusions of pooled random-donor platelets. Of the four assays (platelet suspension immunofluorescence, PSIFT; 51 Cr release; microlymphocytotoxicity; and a monoclonal anti-IgG assay, MAIA), the MAIA was most predictive of platelet transfusion outcome (predictability, 74% for one-hour posttransfusion platelet recovery and 76% for 24-hour recovery). The only other assay to reach statistical significance was the PSIFT (63% predictability for one-hour posttransfusion recovery). The degree of HLA compatibility between donor and recipient (exact matches v those utilizing cross-reactive associations) was unrelated to the ability of the MAIA to predict transfusion results. The MAIA may be capable of differentiating HLA antibodies, ABO antibodies, and platelet-specific antibodies responsible for failure of HLA-matched and selectively mismatched single-donor platelet transfusions

  17. Characterization of Leukocyte-platelet Rich Fibrin, A Novel Biomaterial

    OpenAIRE

    Madurantakam, Parthasarathy; Yoganarasimha, Suyog; Hasan, Fadi K.

    2015-01-01

    Autologous platelet concentrates represent promising innovative tools in the field of regenerative medicine and have been extensively used in oral surgery. Unlike platelet rich plasma (PRP) that is a gel or a suspension, Leukocyte-Platelet Rich Fibrin (L-PRF) is a solid 3D fibrin membrane generated chair-side from whole blood containing no anti-coagulant. The membrane has a dense three dimensional fibrin matrix with enriched platelets and abundant growth factors. L-PRF is a popular adjunct in...

  18. In vitro model of platelet aggregation in stenotic arteries

    International Nuclear Information System (INIS)

    Morley, D.; Santamore, W.P.

    1988-01-01

    Clinical and experimental evidence suggest a strong relationship between arterial stenosis, platelet aggregation, and subsequent thrombus formation. To facilitate the study of platelet accumulation in stenotic arteries, we developed an in vitro preparation. Arterial segments were perfused with whole citrated blood. A stenosis was created by applying an external plastic constrictor to the artery. Platelet accumulation within the stenosis was assessed by scanning electron microscopy and by radioactive counts from Indium-111 labeled platelets. Utilizing this preparation, 30 carotid arterial segments from 10 mongrel dogs were perfused at 100 mmHg for 15 min. In 10 arteries without a stenosis, scanning electron microscopy and radioactive counts demonstrated little platelet accumulation. In contrast, extensive platelet aggregation was observed in 10 arteries with stenoses. Moreover, in 10 stenotic arteries exposed to the thromboxane mimetic, U46619 (Upjohn Diagnostic Group), scanning electron microscopy and radioactive counts demonstrated a significant increase in platelet deposition. Conversely, we demonstrated a dimunition of platelet accumulation in stenosed arterial segments exposed to the prostacyclin analogue platelet inhibitor, Iloprost. The in vitro preparation allows precise control of hemodynamic variables and makes it possible to perform multiple tests on segments of the same vessel from the same animal

  19. Platelets as autonomous drones for hemostatic and immune surveillance.

    Science.gov (United States)

    Li, Jackson LiangYao; Zarbock, Alexander; Hidalgo, Andrés

    2017-07-18

    Platelets participate in many important physiological processes, including hemostasis and immunity. However, despite their broad participation in these evolutionarily critical roles, the anucleate platelet is uniquely mammalian. In contrast with the large nucleated equivalents in lower vertebrates, we find that the design template for the evolutionary specialization of platelets shares remarkable similarities with human-engineered unmanned aerial vehicles in terms of overall autonomy, maneuverability, and expendability. Here, we review evidence illustrating how platelets are uniquely suited for surveillance and the manner in which they consequently provide various types of support to other cell types. © 2017 Li et al.

  20. Polarised infrared cathodoluminescence from platelet defects in natural diamonds

    International Nuclear Information System (INIS)

    Kiflawi, I.; Lang, A.R.

    1977-01-01

    It is reported that the large platelet defects occasionally found in natural diamonds emit polarised cathodoluminescence in the near infrared. There is much uncertainty regarding the composition and structure of the platelets. New findings on the optical properties of the platelets are discussed. The discovery that cathodoluminescence from giant platelets can be seen in the near infrared using an image converter was followed up by photographic recording with Kodak high speed infrared films, and it was found that the infrared emission from the platelets is polarised in the platelet plane with a considerably higher polarisation ratio than in the case of their visible emissions. In order to assess the degree of polarisation of the infrared emission a Polaroid Type HR linear polariser was used, which is very effective at the longest wavelengths recorded by the Kodak high speed infrared film. The high degree of polarisation of the platelet infrared emission constitutes a well defined optical characteristic that any model for platelet structure, and for optical processes associated with platelets, must satisfactorily accommodate. (U.K.)