WorldWideScience

Sample records for bk070044 platelet pgd

  1. Niacin and biosynthesis of PGD2 by platelet COX-1 in mice and humans

    Science.gov (United States)

    Song, Wen-Liang; Stubbe, Jane; Ricciotti, Emanuela; Alamuddin, Naji; Ibrahim, Salam; Crichton, Irene; Prempeh, Maxwell; Lawson, John A.; Wilensky, Robert L.; Rasmussen, Lars Melholt; Puré, Ellen; FitzGerald, Garret A.

    2012-01-01

    The clinical use of niacin to treat dyslipidemic conditions is limited by noxious side effects, most commonly facial flushing. In mice, niacin-induced flushing results from COX-1–dependent formation of PGD2 and PGE2 followed by COX-2–dependent production of PGE2. Consistent with this, niacin-induced flushing in humans is attenuated when niacin is combined with an antagonist of the PGD2 receptor DP1. NSAID-mediated suppression of COX-2–derived PGI2 has negative cardiovascular consequences, yet little is known about the cardiovascular biology of PGD2. Here, we show that PGD2 biosynthesis is augmented during platelet activation in humans and, although vascular expression of DP1 is conserved between humans and mice, platelet DP1 is not present in mice. Despite this, DP1 deletion in mice augmented aneurysm formation and the hypertensive response to Ang II and accelerated atherogenesis and thrombogenesis. Furthermore, COX inhibitors in humans, as well as platelet depletion, COX-1 knockdown, and COX-2 deletion in mice, revealed that niacin evoked platelet COX-1–derived PGD2 biosynthesis. Finally, ADP-induced spreading on fibrinogen was augmented by niacin in washed human platelets, coincident with increased thromboxane (Tx) formation. However, in platelet-rich plasma, where formation of both Tx and PGD2 was increased, spreading was not as pronounced and was inhibited by DP1 activation. Thus, PGD2, like PGI2, may function as a homeostatic response to thrombogenic and hypertensive stimuli and may have particular relevance as a constraint on platelets during niacin therapy. PMID:22406532

  2. PGD-ens paradokser

    Directory of Open Access Journals (Sweden)

    Bjørn Hofmann

    2011-10-01

    Full Text Available Bakgrunn: Preimplantasjonsgenetisk diagnostikk (PGD er en genetisk undersøkelse av befruktede egg før de settes inn i livmoren i forbindelse med assistert reproduksjon. Hensikten med PGD er å unngå at det fremtidige barnet får en alvorlig arvelig sykdom, og at par som på grunn av arvelig sykdom har vansker med å få barn, kan få avkom. PGD er kontroversielt og et sentralt tema for den pågående vurderingen og revisjonen av bioteknologiloven.Metode: Paradoksteori anvendes for å identifisere og analysere noen av kontroversene ved PGD. Det skilles mellom tilsynelatende paradokser, antinomier og aporier. Materialet er offentlige dokumenter, debattinnlegg og faglitteratur.Resultater: Det finnes en rekke tilsynelatende paradokser på PGD-ens område, slik som at PGD gjøres selv om det er svært liten sannsynlighet for at det blir født et alvorlig sykt barn, og at det gjøres PGD for mindre alvorlige sykdommer når forutsetningen for PGD er alvorlig arvelig sykdom. Samtidig finnes det også antinomier: At PGD gir rett til helsehjelp uten at det eksisterer noen pasient, og at PGD gjennomføres selv ved høye kostnader og lav suksessrate. Om embryoet og fosteret har moralsk status og rett på beskyttelse, synes å utgjøre en apori.Konklusjon: Å formulere moralske utfordringer som paradokser kan være en fruktbar måte å tydeliggjøre utfordringer og motsetninger på. Dessuten kan det styre innsatsen: Vi bør bestrebe oss på å rydde opp i tilsynelatende paradokser, jobbe hardere med grunnlagsutfordringene ved antinomier og til en viss grad akseptere motsetningene ved aporiene.Nøkkelord: Preimplantasjonsgenetisk diagnostikk, paradoks, antinomi, aporiEnglish summary: PGD's ParadoxesBackground: Pre-implantation genetic diagnosis (PGD is a genetic test of embryos before implantation as part of in vitro fertilization. The purpose of using PGD is to help people avoid having children with serious genetic disease and to help those with

  3. PGD-ens paradokser

    OpenAIRE

    Hofmann, Bjørn

    2011-01-01

    Bakgrunn: Preimplantasjonsgenetisk diagnostikk (PGD) er en genetisk undersøkelse av befruktede egg før de settes inn i livmoren i forbindelse med assistert reproduksjon. Hensikten med PGD er å unngå at det fremtidige barnet får en alvorlig arvelig sykdom, og at par som på grunn av arvelig sykdom har vansker med å få barn, kan få avkom. PGD er kontroversielt og et sentralt tema for den pågående vurderingen og revisjonen av bioteknologiloven.Metode: Paradoksteori anvendes for å identifisere og ...

  4. Platelets

    Science.gov (United States)

    ... allow them to change shape when they become sticky. The pictures above show normal platelets on the ... Too Many Platelets Rare conditions result in the bone marrow producing too many platelets, sometimes as many ...

  5. [Ethical aspects of preimplantation genetic diagnosis (PGD)].

    Science.gov (United States)

    Mauron, Alex

    2011-01-01

    The controversy surrounding PGD has not abated in recent times. This is especially the case for PGD-based tissue typing, which is used to select a future child who could serve as a stem cell donor for an older sick sibling. We examine three types of ethical argument cited against PGD in general, and specifically against tissue-typing PGD. These arguments focus on the moral status of the early embryo, the eugenics issue, and the charge that the future child is being exploited. We conclude that none of these three arguments is unassailable, and that it is the reproductive freedom of couples considering PGD that should prevail.

  6. Accreditation of the PGD laboratory.

    Science.gov (United States)

    Harper, J C; Sengupta, S; Vesela, K; Thornhill, A; Dequeker, E; Coonen, E; Morris, M A

    2010-04-01

    Accreditation according to an internationally recognized standard is increasingly acknowledged as the single most effective route to comprehensive laboratory quality assurance, and many countries are progressively moving towards compulsory accreditation of medical testing laboratories. The ESHRE PGD Consortium and some regulatory bodies recommend that all PGD laboratories should be accredited or working actively towards accreditation, according to the internationally recognized standard ISO 15189, 'Medical laboratories-Particular requirements for quality and competence'. ISO 15189 requires comprehensive quality assurance. Detailed management and technical requirements are defined in the two major chapters. The management requirements address quality management including the quality policy and manual, document control, non-conformities and corrective actions, continual improvement, auditing, management review, contracts, referrals and resolution of complaints. Technical requirements include personnel competence (both technical and medical), equipment, accommodation and environment, and pre-analytical, analytical and post-analytical processes. Emphasis is placed on the particular requirements of patient care: notably sample identification and traceability, test validation and interpretation and reporting of results. Quality indicators must be developed to monitor contributions to patient care and continual improvement. We discuss the implementation of ISO 15189 with a specific emphasis on the PGD laboratory, highlight elements of particular importance or difficulty and provide suggestions of effective and efficient ways to obtain accreditation. The focus is on the European environment although the principles are globally applicable.

  7. Views of internists towards uses of PGD

    Science.gov (United States)

    Chung, Wendy; Marder, Karen; Shanmugham, Anita; Chin, Lisa J.; Stark, Meredith; Leu, Cheng-Shiun; Appelbaum, Paul S.

    2012-01-01

    Preimplantation genetic diagnosis (PGD) is increasingly available, but how physicians view it is unclear. Internists are gatekeepers and sources of information, often treating disorders for which PGD is possible. This quantitative study surveyed 220 US internists, who were found to be divided. Many would recommend PGD for cystic fibrosis (CF; 33.7%), breast cancer (BRCA; 23.4%), familial adenomatous polyposis (FAP; 20.6%) and familial hypertrophic cardiomyopathy (19.9%), but few for social sex selection (5.2%); however, in each case, >50% were unsure. Of those surveyed, 4.9% have suggested PGD to patients. Only 7.1% felt qualified to answer patient questions about it. Internists who would refer for PGD had completed medical training less recently and, for CF, were more likely to have privately insured patients (P PGD differently, partly reflecting varying ages of onset and disease treatability. These data have critical implications for training, research and practice. PMID:23276655

  8. Views of Preimplantation Genetic Diagnosis (PGD) among Psychiatrists and Neurologists

    Science.gov (United States)

    Abbate, Kristopher J.; Klitzman, Robert; Chung, Wendy K.; Ottman, Ruth; Leu, Cheng-Shiun; Appelbaum, Paul S.

    2014-01-01

    Objective As prenatal genetic testing (GT) and Preimplantation Genetic Diagnosis (PGD) use increase, providers in many specialties may play roles in patient discussions and referrals. Hence, we examined key aspects of neurologists’ and psychiatrists’ views and approaches. Study Design We surveyed attitudes and practices among 163 neurologists and 372 psychiatrists. Results 24.9% of neurologists and 31.9% of psychiatrists had discussed prenatal GT with patients, but 95.3% didn’t feel comfortable discussing PGD; only 2.9% discussed it; and only 1.8% had patients ask about PGD. Most would refer for PGD for Huntington’s disease (HD) and Tay-Sachs, fewer for Cystic Fibrosis (CF), and fewer still for autism, Alzheimer’s (AD), or gender selection for family balancing; in each of these cases, psychiatrists > neurologists. Providers who’d refer for PGD for HD, CF, or gender selection differed from others in proportions of patients with insurance, were more likely to have undergone a GT themselves, and be concerned about discrimination. Conclusions These data, the first to examine how neurologists and psychiatrists view PGD, suggest they don’t feel comfortable discussing PGD, but have strong views about its use. Potential PGD use is associated with concerns about discrimination, and less experience with GT. These data highlight needs for enhancing education about these technologies among various providers. PMID:25098029

  9. Preimplantation genetic diagnosis (PGD): European perspectives and the German situation.

    Science.gov (United States)

    Krones, Tanja; Richter, Gerd

    2004-10-01

    This article gives an overview about the ethical dispute on preimplantation genetic diagnosis (PGD), its legal status and its practical usage in Europe. We provide a detailed description of the situation in Germany wherein prenatal diagnosis is routinely applied, but PGD is prohibited on the basis of the internationally unique embryo protection act (EPA) that was put into force in 1991. Both PGD and stem cell research were vigorously debated in Germany during the last four years. As regards the PGD debate specifically, the voices of the ones directly affected were not adequately taken into consideration. We describe the predominant lines of argumentation in this debate and some essential results of our "bioethical field study" of opinions on and usage of PGD in Germany and their implications for the German legislation and ethical theory.

  10. Gender eugenics? The ethics of PGD for intersex conditions.

    Science.gov (United States)

    Sparrow, Robert

    2013-01-01

    This article discusses the ethics of the use of preimplantation genetic diagnosis (PGD) to prevent the birth of children with intersex conditions/disorders of sex development (DSDs), such as congenital adrenal hyperplasia (CAH) and androgen insensitivity syndrome (AIS). While pediatric surgeries performed on children with ambiguous genitalia have been the topic of intense bioethical controversy, there has been almost no discussion to date of the ethics of the use of PGD to reduce the prevalence of these conditions. I suggest that PGD for those conditions that involve serious medical risks for those born with them is morally permissible and that PGD for other "cosmetic" variations in sexual anatomy is more defensible than might first appear. However, importantly, the arguments that establish the latter claim have radical and disturbing implications for our attitude toward diversity more generally.

  11. Transferring embryos with indeterminate PGD results: the ethical implications

    OpenAIRE

    Insogna, Iris G.; Ginsburg, Elizabeth

    2016-01-01

    Background In vitro fertilization (IVF) and pre-implantation genetic diagnosis (PGD) are becoming increasingly common techniques to select embryos that are unaffected by a known genetic disorder. Though IVF-PGD has high success rates, 7.5?% of blastocysts have inconclusive results after testing. A recent case involving a known BRCA-1 carrier was brought before our Assisted Reproductive Technology Ethics Committee in order to gain a better appreciation for the ethical implications surrounding ...

  12. Clinical guidelines for IVF with PGD for HLA matching.

    Science.gov (United States)

    Tur-Kaspa, Ilan; Jeelani, Roohi

    2015-02-01

    Preimplantation genetic diagnosis (PGD) for human leukocyte antigen (HLA) typing is an established procedure for conceiving a child who may donate cord blood or haematopoietic stem cells for transplantation to save an ill sibling. Haematopoietic stem cell transplantation (HSCT) from related matched donors improves overall survival compared with unrelated or non-matched donors. Since HSCT from related matched-donors is unavailable for 70% of patients, IVF for PGD-HLA is a relevant clinical option. Recent success of HSCT after PGD-HLA, and excellent health and family support of the children born, suggests that debate over this kind of 'designer baby' and 'gift of life' should subside. Discussions about IVF for PGD-HLA should be held with families when a related matched-donor is unavailable, when HSCT can wait at least 9-12 months, within weeks of diagnosis irrespective of prognosis, and when the mother is of reproductive age. Related half-matched egg donors may also be considered. National and international collaborations should be established, and couples choosing this modality should be referred to experienced IVF and PGD centres. Clinical guidelines will improve physician and patient awareness of IVF for PGD-HLA and its role in advancing the clinical care of children in need of HSCT. Copyright © 2014 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.

  13. ESHRE PGD Consortium/Embryology Special Interest Group--best practice guidelines for polar body and embryo biopsy for preimplantation genetic diagnosis/screening (PGD/PGS)

    DEFF Research Database (Denmark)

    Harton, G L; Magli, M C; Lundin, K

    2011-01-01

    than one document that covers all of PGD as in the original publication, these guidelines are separated into four new documents that apply to different aspects of a PGD programme; Organization of a PGD centre, fluorescence in situ hybridization-based testing, amplification-based testing and polar body...... and embryo biopsy for preimplantation genetic diagnosis/screening (PGD/PGS). Here we have updated the sections that pertain to embryology (including cryopreservation) and biopsy of embryos prior to PGD or PGS. Topics covered in this guideline include uses of embryo biopsy, laboratory issues relating...... to biopsy, timing of biopsy, biopsy procedure and cryopreserving biopsied embryos....

  14. PGD for monogenic disorders: aspects of molecular biology.

    Science.gov (United States)

    Spits, Claudia; Sermon, Karen

    2009-01-01

    Preimplantation genetic diagnosis (PGD) for monogenic diseases has known a considerable evolution since its first application in the early 1990s. Especially the technical aspects of the genetic diagnosis itself, the single-cell genetic analysis, has constantly evolved to reach levels of accuracy and efficiency nearing those of genetic diagnosis on regular DNA samples. In this review, we will focus on the molecular biological techniques that are currently in use in the most advanced centers for PGD for monogenic disorders, including multiplex polymerase chain reaction (PCR) and post-PCR diagnostic methods, whole genome amplification (WGA) and multiple displacement amplification (MDA). As it becomes more and more clear that when it comes to ethically difficult indications, PGD goes further than prenatal diagnosis (PND), we will also briefly discuss ethical issues. Copyright (c) 2008 John Wiley & Sons, Ltd.

  15. Attitudes Toward Pre-implantation Genetic Diagnosis (PGD) for Genetic Disorders Among Potential Users in Malaysia.

    Science.gov (United States)

    Olesen, Angelina Patrick; Nor, Siti Nurani Mohd; Amin, Latifah

    2016-02-01

    While pre-implantation genetic diagnosis (PGD) is available and legal in Malaysia, there is an ongoing controversy debate about its use. There are few studies available on individuals' attitudes toward PGD, particularly among those who have a genetic disease, or whose children have a genetic disease. To the best of our knowledge, this is, in fact, the first study of its kind in Malaysia. We conducted in-depth interviews, using semi-structured questionnaires, with seven selected potential PGD users regarding their knowledge, attitudes and decisions relating to the use PGD. The criteria for selecting potential PGD users were that they or their children had a genetic disease, and they desired to have another child who would be free of genetic disease. All participants had heard of PGD and five of them were considering its use. The participants' attitudes toward PGD were based on several different considerations that were influenced by various factors. These included: the benefit-risk balance of PGD, personal experiences of having a genetic disease, religious beliefs, personal values and cost. The study's findings suggest that the selected Malaysian participants, as potential PGD users, were supportive but cautious regarding the use of PGD for medical purposes, particularly in relation to others whose experiences were similar. More broadly, the paper highlights the link between the participants' personal experiences and their beliefs regarding the appropriateness, for others, of individual decision-making on PGD, which has not been revealed by previous studies.

  16. PGD patients' and providers' attitudes to the use and regulation of preimplantation genetic diagnosis.

    Science.gov (United States)

    Kalfoglou, Andrea L; Scott, Joan; Hudson, Kathy

    2005-10-01

    Preimplantation genetic diagnosis (PGD) providers and patients have a vested interest in policy related to the use and regulation of PGD. To understand their experiences and attitudes, 32 in-depth interviews were conducted. Participants included 13 people at risk of transmitting a single-gene alteration to their children (10/13 had actually used PGD to try to have an unaffected child) and 19 PGD service providers (four nurses, five genetic counsellors, two reproductive endocrinologists, two geneticists, two physician-geneticists, two embryologists, and two laboratory directors). Virtually all participants supported the use of PGD to avoid severe, life-threatening genetic illness or to select embryos that are a tissue match for a sick sibling, but their attitudes varied significantly over the appropriateness of using PGD to avoid adult-onset genetic disease, to select for sex, or to select for other non-medical characteristics. There was disagreement within the PGD provider community about whether or not PGD is experimental. Participants were more concerned about overzealous government regulation of PGD creating barriers to access than potential abuses of the technology, and expected the PGD provider community to take the lead in ensuring that PGD is used for ethically appropriate purposes.

  17. Timing embryo biopsy for PGD - before or after cryopreservation?

    Science.gov (United States)

    Shinar, S; Kornecki, N; Schwartz, T; Mey-Raz, N; Amir, H; Almog, B; Shavit, T; Hasson, J

    2016-09-01

    Pre-implantation genetic diagnosis (PGD) is required in order to screen and diagnose embryos of patients at risk of having a genetically affected offspring. A biopsy to diagnose the genetic profile of the embryo may be performed either before or after cryopreservation. The aim of this study was to determine which biopsy timing yields higher embryo survival rates. Retrospective cohort study of all PGD patients in a public IVF unit between 2010 and 2013. Inclusion criteria were patients with good-quality embryos available for cryopreservation by the slow freezing method. Embryos were divided into two groups: biopsy before and biopsy after cryopreservation. The primary outcome was embryo survival rates post thawing. Sixty-five patients met inclusion criteria. 145 embryos were biopsied before cryopreservation and 228 embryos were cryopreserved and biopsied after thawing. Embryo survival was significantly greater in the latter group (77% vs. 68%, p Cryopreservation preceding biopsy results in better embryo survival compared to biopsy before cryopreservation.

  18. Transferring embryos with indeterminate PGD results: the ethical implications.

    Science.gov (United States)

    Insogna, Iris G; Ginsburg, Elizabeth

    2016-01-01

    In vitro fertilization (IVF) and pre-implantation genetic diagnosis (PGD) are becoming increasingly common techniques to select embryos that are unaffected by a known genetic disorder. Though IVF-PGD has high success rates, 7.5 % of blastocysts have inconclusive results after testing. A recent case involving a known BRCA-1 carrier was brought before our Assisted Reproductive Technology Ethics Committee in order to gain a better appreciation for the ethical implications surrounding the transfer of embryos with indeterminate testing. Thirty-nine year old G0 BRCA-1 carrier requiring IVF for male factor infertility. The couple elected for PGD to select against BRCA-1 gene carrier embryos. However, several embryos were returned with inconclusive results. The couple wished to proceed with the transfer of embryos with an unknown carrier status. The case was presented before our Assisted Reproductive Technology Ethics Committee. Many considerations were explored, including the physician's duty to protect patient autonomy, the physician's duty to act in the best interest of the future child, and the physician's duty towards society. Transferring both embryos with unknown carrier status and known-carrier status was debated. Ultimately, the transfer of inconclusive embryos was felt to be ethically permissible in most cases if patients had been adequately counseled. However, the re-biopsy of embryos with inconclusive testing results was encouraged. The transfer of known-carrier embryos was felt to be unethical for certain disease-states, depending on the severity of illness and timing of disease onset. We strongly encourage physicians to create an action plan in advance with their patients, prior to testing, in the event that embryos are returned with inconclusive PGD results. The committee's decision, though helpful in guiding practice, should not overshadow the individual physician-patient relationship, and the need for thorough counseling.

  19. 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

  20. Knowledge and Educational Needs about Pre-Implantation Genetic Diagnosis (PGD among Oncology Nurses

    Directory of Open Access Journals (Sweden)

    Gwendolyn P. Quinn

    2014-06-01

    Full Text Available Preimplantation genetic diagnosis (PGD, a form of assisted reproductive technology, is a new technology with limited awareness among health care professionals and hereditary cancer families. Nurses play a key role in the care of patients and are often in an ideal position to discuss and refer patients on sensitive quality of life issues, such as PGD. Two hundred and one nurses at Moffitt Cancer Center (MCC responded to an online survey assessing knowledge and educational needs regarding PGD and families with hereditary cancer. The majority of respondents were female (n = 188, white (n = 175, had an RN/BSN degree (n = 83, and provided outpatient care at the cancer center (n = 102. More than half of respondents (78% were unfamiliar with PGD prior to the survey and respondents who had heard of PGD had limited knowledge. More than half of the participants reported PGD was an acceptable option for families with hereditary cancer syndromes and thought individuals with a strong family or personal history should be provided with information about PGD. This study indicates that oncology nurses may benefit from and desire education about PGD. With advances in reproductive technology and options, further PGD education is needed among healthcare professionals. An examination of current oncology nursing curriculum and competencies regarding genetic education may identify need for future revisions and updates.

  1. On the relation between moral, legal and evaluative justifications of pre-implantation genetic diagnosis (PGD).

    Science.gov (United States)

    Lohmann, Georg

    2003-01-01

    In Germany the question whether to uphold or repeal the judicial prohibition on Pre-implantation Genetic Diagnosis (PGD) is being debated from quite different standpoints. This paper differentiates the major arguments according to their reasons as a) moral, b) evaluative (i.e. cultural/religious), and c) legal. The arguments for and against PGD can be divided by content into three groups: arguments relating to the status of the embryo, focusing on individual actions in the implementation of PGD, and relating to the foreseeable or probable consequences of PGD. In Germany, from a legal perspective, the status of the embryo does not permit the intervention of PGD; from a purely moral perspective, a prohibition on PGD does not appear defensible. It remains an open question, however, whether the moral argument permitting PGD should be restricted for evaluative (cultural) reasons. The paper discusses the species-ethical reasons, for which Jurgen Habermas sees worrisome consequences in the wake of PGD to the extent that we comprehend it as the forerunner of a 'positive eugenics'. It would so disrupt the natural preconditions of our universal morality. The question of whether to prohibit or allow PGD is not merely a question of simple moral and/or legal arguments, but demands a choice between evaluative, moral and (still to be specified) species-ethical arguments, and the question remains open.

  2. Ethics of PGD: thoughts on the consequences of typing HLA in embryos.

    Science.gov (United States)

    Edwards, R G

    2004-08-01

    As with so many fields of study associated with assisted human reproduction, many ethical issues are raised by the practice of preimplantation diagnosis of inherited disease (PGD). Some are part and parcel of assisted conception, e.g.the rights of human embryos in vitro and of embryologists to establish them, carry out research and discard them. Others unique to clinical PGD were discussed at an earlier meeting on PGD (Edwards et al., 2003). Recent developments in PGD are discussed briefly in this Commentary, especially the ethics of designer babies.

  3. PGD-based modeling of materials, structures and processes

    CERN Document Server

    Chinesta, Francisco

    2014-01-01

    This book focuses on the development of a new simulation paradigm allowing for the solution of models that up to now have never been resolved and which result in spectacular CPU time savings (in the order of millions) that, combined with supercomputing, could revolutionize future ICT (information and communication technologies) at the heart of science and technology. The authors have recently proposed a new paradigm for simulation-based engineering sciences called Proper Generalized Decomposition, PGD, which has proved a tremendous potential in many aspects of forming process simulation. In this book a review of the basics of the technique is made, together with different examples of application.

  4. Recurrent miscarriage in translocation carriers : No differences in clinical characteristics between couples who accept and couples who decline PGD

    NARCIS (Netherlands)

    De Krom, G.; Arens, Y. H J M; Coonen, E.; Van Ravenswaaij-Arts, C. M A; Meijer-Hoogeveen, M.; Evers, J. L H; van Golde, Ron J T; de Die-Smulders, Christine E M

    2015-01-01

    Study question: Doclinical characteristics of recurrent miscarriage couples with a chromosomal abnormality and who opt for PGD differ from couples that decline PGD after extensive genetic counselling? Summary answer: No differences in clinical characteristics are identified between recurrent

  5. Recurrent miscarriage in translocation carriers : no differences in clinical characteristics between couples who accept and couples who decline PGD

    NARCIS (Netherlands)

    De Krom, G.; Arens, Y. H. J. M.; Coonen, E.; Van Ravenswaaij-Arts, C. M. A.; Meijer-Hoogeveen, M.; Evers, J. L. H.; Van Golde, R. J. T.; De Die-Smulders, C. E. M.

    STUDY QUESTION: Do clinical characteristics of recurrent miscarriage couples with a chromosomal abnormality and who opt for PGD differ from couples that decline PGD after extensive genetic counselling? SUMMARY ANSWER: No differences in clinical characteristics are identified between recurrent

  6. The politics of human embryo research and the motivation to achieve PGD.

    Science.gov (United States)

    Theodosiou, Anastasia A; Johnson, Martin H

    2011-05-01

    This article reports a historical study of factors influencing the achievement of clinical preimplantation genetic diagnosis (PGD) in 1990, 22 years after its first demonstration in animals. During the 1970s, research on PGD continued in large farm animals, but serious interest in human PGD was not evident until 1986. First, interest in PGD during the 1970s waned with the advent of prenatal testing, which for gynaecologists was clinically more familiar, technically simpler and ethically less challenging than IVF. Indeed, IVF was viewed with widespread suspicion until the first IVF births in 1978. Second, interest in clinical PGD was stimulated by the UK Parliamentary reaction against human embryo research that greeted the Warnock Report in 1984. This hostility led scientists to initiate a pro-research campaign, further galvanized in 1985 by MP Enoch Powell's bid to ban such research. However, while Powell abhorred embryo research, he approved of PGD, a stance that divided the anti-research lobby. Accordingly, the campaigners for research emphasized that it was needed to achieve PGD. Powell demanded evidence of such projects and PGD research increased from 1986. It is concluded that UK political debates on embryo research played a critical role in stimulating the achievement of clinical PGD. Human pregnancies following preimplantation genetic diagnosis (PGD) for embryo sex were announced in 1990, 22 years after the technique was pioneered in animals. PGD in humans required not only technological advances, such as IVF and sensitive diagnostic tests, but also the motivation to develop and apply them. Our historical analysis shows that, although research on PGD continued in large farm animals during the 1970s, and techniques of the required sensitivity were developed on mouse embryo models, interest in clinical PGD was not evident until 1986. Two factors stimulated this sudden change in motivation. First, interest in PGD was depressed during the 1970s by the advent of

  7. 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...

  8. Single prostacyclin receptor of gel-filtered platelets provides a correlation with antiaggregatory potency of PGI2 mimics

    International Nuclear Information System (INIS)

    Eggerman, T.L.; Hartzell, C.J.; Selfe, S.; Andersen, N.H.

    1987-01-01

    Gel-filtered human platelets (GFP) display only a single binding site for [ 3 H]-PGI2: KD = 61nM, 234 fmol/10(8) platelets (1410 sites/platelet). Platelet-rich plasma (PRP) displays the same receptor density but the KD value increases to 123 nM due to protein binding of PGI2 which lowers its effective concentration. The [ 3 H]-PGI2/GFP binding assay has been used to evaluate the molecular basis of aggregation inhibition for prostacyclin analogs and mimics, three PGE type structures, and PGD2. Antiaggregatory IC50s and radioligand binding IC50s correlate for PGE2, E1, and six PGI2 analogs. PGD2, and to a lesser extent 6-oxo-PGE1, display greater antiaggregatory potency than expected based on PGI2-binding site affinity data

  9. Single-cell high resolution melting analysis: A novel, generic, pre-implantation genetic diagnosis (PGD) method applied to cystic fibrosis (HRMA CF-PGD).

    Science.gov (United States)

    Destouni, A; Poulou, M; Kakourou, G; Vrettou, C; Tzetis, M; Traeger-Synodinos, J; Kitsiou-Tzeli, S

    2016-03-01

    Institutions offering CF-PGD face the challenge of developing and optimizing single cell genotyping protocols that should cover for the extremely heterogeneous CF mutation spectrum. Here we report the development and successful clinical application of a generic CF-PGD protocol to facilitate direct detection of any CFTR nucleotide variation(s) by HRMA and simultaneous confirmation of diagnosis through haplotype analysis. A multiplex PCR was optimized supporting co-amplification of any CFTR exon-region, along with 6 closely linked STRs. Single cell genotypes were established through HRM analysis following melting of the 2nd round PCR products and were confirmed by STR haplotype analysis of the 1st PCR products. The protocol was validated pre-clinically, by testing 208 single lymphocytes, isolated from whole blood samples from 4 validation family trios. Fifteen PGD cycles were performed and 103 embryos were biopsied. In 15 clinical PGD cycles, genotypes were achieved in 88/93 (94.6%) embryo biopsy samples, of which 57/88 (64.8%) were deemed genetically suitable for embryo transfer. Amplification failed at all loci for 10/103 blastomeres biopsied from poor quality embryos. Six clinical pregnancies were achieved (2 twin, 4 singletons). PGD genotypes were confirmed following conventional amniocentesis or chorionic villus sampling in all achieved pregnancies. The single cell HRMA CF-PGD protocol described herein is a flexible, generic, low cost and robust genotyping method, which facilitates the analysis of any CFTR genotype combination. Single-cell HRMA can be beneficial to other clinical settings, for example the detection of single nucleotide variants in single cells derived from clinical tumor samples. Copyright © 2015 European Cystic Fibrosis Society. Published by Elsevier B.V. All rights reserved.

  10. Addressing the idiosyncratic needs of Orthodox Jewish couples requesting sex selection by preimplantation genetic diagnosis (PGD)

    OpenAIRE

    Grazi, Richard V.; Wolowelsky, Joel B.

    2006-01-01

    We report here on ethical considerations addressing the idiosyncratic needs of two Orthodox Jewish couples requesting sex selection through PGD. The patients’ considerations stem from generally healthy concerns, are not based on any gender biases and have little chance of having any major societal impact, given the idiosyncratic nature of the situation. Halakhah, the legal and ethical system of rabbinic Orthodox Judaism, generally opposes sex selection through PGD for nonmedical reasons, but ...

  11. Moral attitudes and beliefs among couples pursuing PGD for sex selection.

    Science.gov (United States)

    Sharp, Richard R; McGowan, Michelle L; Verma, Jonathan A; Landy, David C; McAdoo, Sallie; Carson, Sandra A; Simpson, Joe Leigh; McCullough, Laurence B

    2010-12-01

    This article reports the results from a study of couples participating in a research protocol in which IVF/preimplantation genetic diagnosis (PGD) was available for non-medical sex selection. The study sought to characterize the moral attitudes and beliefs of couples actively pursuing IVF/PGD solely for purposes related to sex selection. Eighteen couples participated in ethnographic interviews from November 2005 to April 2006. These interviews explored couples' motivations for pursuing sex selection, moral beliefs and attitudes regarding sex selection and sources of moral ambivalence about the use of IVF/PGD for sex selection. Couples reported a combination of motivations for pursuing sex selection, including a desire to limit family size, concerns about parental age and financial concerns about multiple pregnancies. Many couples compared their decision to choices about abortion, maintaining that individuals have a right to make such decisions privately. Couples frequently expressed anxiety about telling their other children and family members about their plans to use IVF/PGD for sex selection. Few couples cited concerns about the physical or emotional burdens of IVF/PGD. The study's findings suggest that couples pursuing IVF/PGD for sex selection view this as an ethically complex decision and express considerable uncertainty about the ethical acceptability of this practice. Copyright © 2010 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.

  12. PGD to reduce reproductive risk: the case of mitochondrial DNA disorders.

    Science.gov (United States)

    Bredenoord, A L; Dondorp, W; Pennings, G; De Die-Smulders, C E M; De Wert, G

    2008-11-01

    This paper discusses the pros and cons of introducing PGD for mitochondrial DNA (mtDNA) disorders such as NARP (Neurogenic muscle weakness, Ataxia, Retinis Pigmentosa)/Leigh, MELAS (Mitochondrial myopathy, Encephalopathy, Lactic acidosis, and Stroke-like episodes), private mtDNA mutations and LHON (Leber Hereditary Optic Neuropathy). Although there is little experience with PGD for mtDNA disorders, it is reasonable to assume that in many cases, the best one can achieve is the selection of the 'least' affected embryos for transfer. So instead of 'promising' parents a healthy child, PGD in these cases can only aim at reducing reproductive risk. From an ethical point of view, this raises challenging questions about parental and medical responsibilities. The main argument in favour of PGD is that it offers couples at risk the opportunity of reducing their chances of having a severely affected child. Potential objections are manifold, but we conclude that none of them supplies convincing moral arguments to regard risk-reducing PGD as unacceptable. Nevertheless, introducing this new application of PGD in clinical practice will raise further complex issues of determining conditions for its responsible use.

  13. Radiolabeled platelets

    International Nuclear Information System (INIS)

    Cunningham, D.A.; Siegel, B.A.

    1982-01-01

    The experimental applications of labeled platelets have expanded greatly since the development of an efficient labeling agent with physical properties suitable for external imaging. The role of both In-111- and Cr-51-labeled platelets in routine clinical studies is discussed. In the case of Cr-51, use is likely to remain confined to occasional platelet kinetic studies. In contrast, the potential applications of In-111-labeled platelets are much broader in scope, but as yet human studies remain in the investigative stage. The available data suggest that the technique is highly specific for various thrombotic processs but rather insensitive and time consuming in its present form

  14. Preimplantation genetic diagnosis (PGD) in Europe: diversity of legislation a challenge to the community and its citizens.

    Science.gov (United States)

    Soini, S

    2007-06-01

    Preimplantation genetic diagnosis (PGD) aims to safeguard the reproductive confidence of couples who have an increased risk of having a child with a serious hereditary disease. Non-directive genetic counselling is an essential part of PGD. Lately, performance of PGD for some new and non-medical indications, such as selecting for a tissue-matching embryo for a saviour sibling, or sex-selection for family-balancing, has raised ethical concerns. Who decides when to perform PGD, and for which conditions? The European member states have very diverse regulation on PGD. Some countries totally ban PGD, while the others keep close track of the new applications. The people in need of PGD seek it in the other member states. These cross-border treatments cause psychological stress and pose many so far unresolved legal questions. The individuals need more information about all the aspects of PGD. This article analyses contemporary indications for PGD in Europe and relevant ethical discussion, and second, shows the diversity in regulation and reflects the consequences thereof.

  15. Public, expert and patients' opinions on preimplantation genetic diagnosis (PGD) in Germany.

    Science.gov (United States)

    Krones, Tanja; Schlüter, Elmar; Manolopoulos, Konstantin; Bock, Karin; Tinneberg, Hans-Rudolf; Koch, Manuela C; Lindner, Martin; Hoffmann, Georg F; Mayatepek, Ertan; Huels, Gerd; Neuwohner, Elke; El Ansari, Susan; Wissner, Thomas; Richter, Gerd

    2005-01-01

    The regulation of reproductive medicine technologies differs significantly among Western industrialized countries. In Germany, preimplantation genetic diagnosis (PGD) is prohibited due to the Embryo Protection Act, which came into force in 1991. In the last 5 years, this prohibition has been vigorously debated. In the present studies, which are part of the German research programme on ethical implications of the Human Genome Project, representative surveys were undertaken to assess the attitudes on PGD in the general population (n = 1017), five relevant expert groups (n = 879), high genetic risk couples (n = 324) and couples undergoing IVF (n = 108). All groups surveyed clearly favoured allowing PGD in Germany. Compared with the results of recently conducted population surveys in the UK and the USA, where PGD is already carried out, public approval of PGD does not differ significantly. The influence of restrictive biopolitics on the apparently liberal public opinion towards new reproductive technology seems to be marginal according to the present data, which should carefully be considered in the ongoing legislation process on human reproduction.

  16. Pandora's box: ethics of PGD for inherited risk of late-onset disorders.

    Science.gov (United States)

    Noble, Ray; Bahadur, Gulam; Iqbal, Mohammad; Sanyal, Arnab

    2008-01-01

    Until recently, the primary use of preimplantation genetic diagnosis (PGD) has been the selection of embryos to avoid lethal or debilitating gene mutations or abnormal chromosome complement. PGD can be used to reduce the risk of transferring to the uterus an embryo with Down syndrome, and parents who are carriers of severe genetic diseases may choose to avoid having children with these debilitating genetic conditions. The use of PGD is now being extended to include gene mutations that increase the risk of late-onset disorders such as breast and ovarian cancer. This paper argues for caution in advocating reproductive methods that are costly, have a limited chance of success, and for which the long-term outcome is unknown. Counselling should allow women a true choice of declining the option of PGD without recrimination, feelings of guilt or social pressure. There is concern that the Human Fertilisation and Embryology Authority has approved extension of PGD to late-onset multifactorial diseases without clear guidelines for its use. Guidelines for embryo selection should be revised to deal with potential conflict between reproductive success and genetic screening for disorders that do not profoundly affect the embryo or the children.

  17. Platelet Donation

    Science.gov (United States)

    ... Drive Biomedical Services Hospital Partners Blood Products Blood Banking Resources Order Blood Products Invoice Central Case Reports ... You need an appointment to donate platelets. Schedule online , through the free Blood Donor App or by ...

  18. Accuracy of preimplantation genetic diagnosis (PGD) of single gene and chromosomal disorders

    Energy Technology Data Exchange (ETDEWEB)

    Verlinsky, Y.; Strom, C.; Rechitsky, S. [Reproductive Genetics Institute, Chicage, IL (United States)] [and others

    1994-09-01

    We have developed a polar body inferred approach for preconception diagnosis of single gene and chromosomal disorders. Preconception PCR or FISH analysis was performed in a total of 310 first polar bodies for the following genetic conditions: cystic fibrosis, hemophilia A, alpha-1-antitrypsin deficiency, Tay Sachs disease, retinitis pigmentosa and common chromosomal trisomies. An important advantage of this approach is the avoidance of sperm (DNA) contamination, which is the major problem of PGD. We are currently applying FISH analysis of biopsied blastomeres, in combination with PCR or separately, and have demonstrated a significant improvement of the accuracy of PGD of X-linked disorders at this stage. Our data have also demonstrated feasibility of the application of FISH technique for PGD of chromosomal disorders. It was possible to detect chromosomal non-disjunctions and chromatid malsegregations in the first meiotic division, as well as to evaluate chromosomal mutations originating from the second meiotic nondisjunction.

  19. An efficient reduced-order method with PGD for solving journal bearing hydrodynamic lubrication problems

    Science.gov (United States)

    Cherabi, Bilal; Hamrani, Abderrachid; Belaidi, Idir; Khelladi, Sofiane; Bakir, Farid

    2016-10-01

    In the present work, a reduced-order method, ;Proper Generalized Decomposition (PGD); is extended and applied to the resolution of the Reynolds equation describing the behavior of the lubricant in hydrodynamic journal bearing. The PGD model is employed to solve the characteristic 'Reynolds' partial differential equation using the separation technique through the alternating direction strategy. The resulting separated-dimension system has a low computation cost compared to classical finite-difference resolution. Several numerical benchmark examples are investigated to verify the validity and accuracy of the proposed method. It has been found that numerical results obtained by the PGD method can achieve an improved convergence rate with a very low computation cost.

  20. 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)

  1. Addressing the idiosyncratic needs of Orthodox Jewish couples requesting sex selection by preimplantation genetic diagnosis (PGD).

    Science.gov (United States)

    Grazi, Richard V; Wolowelsky, Joel B

    2006-01-01

    We report here on ethical considerations addressing the idiosyncratic needs of two Orthodox Jewish couples requesting sex selection through PGD. The patients' considerations stem from generally healthy concerns, are not based on any gender biases and have little chance of having any major societal impact, given the idiosyncratic nature of the situation. Halakhah, the legal and ethical system of rabbinic Orthodox Judaism, generally opposes sex selection through PGD for nonmedical reasons, but would approve the procedure in these cases. Meeting these needs within the context of the doctor-patient relationship necessitates reconsidering to some extent the ASRM Ethics Committee guidelines.

  2. Choosing embryos: ethical complexity and relational autonomy in staff accounts of PGD

    OpenAIRE

    Ehrich, Kathryn; Williams, Clare; Farsides, Bobbie; Sandall, Jane; Scott, Rosamund

    2007-01-01

    Copyright @ 2008 the authors. This article is available in accordance with the Creative Commons Deed, Attribution 2.5, see http://creativecommons.org/licenses/by-nc-nd/2.5/deed.en_CA. The technique of preimplantation genetic diagnosis (PGD) is commonly explained as a way of checking the genes of embryos produced by IVF for serious genetic diseases. However, complex accounts of this technique emerged during ethics discussion groups held for PGD staff. These form part of a study exploring th...

  3. 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. ...

  4. Public Perceptions of Ethical, Legal and Social Implications of Pre-implantation Genetic Diagnosis (PGD) in Malaysia.

    Science.gov (United States)

    Olesen, Angelina P; Mohd Nor, Siti Nurani; Amin, Latifah; Che Ngah, Anisah

    2017-12-01

    Pre-implantation genetic diagnosis (PGD) became well known in Malaysia after the birth of the first Malaysian 'designer baby', Yau Tak in 2004. Two years later, the Malaysian Medical Council implemented the first and only regulation on the use of Pre-implantation Genetic Diagnosis in this country. The birth of Yau Tak triggered a public outcry because PGD was used for non-medical sex selection thus, raising concerns about PGD and its implications for the society. This study aims to explore participants' perceptions of the future implications of PGD for the Malaysian society. We conducted in-depth interviews with 21 participants over a period of one year, using a semi-structured questionnaire. Findings reveal that responses varied substantially among the participants; there was a broad acceptance as well as rejection of PGD. Contentious ethical, legal and social issues of PGD were raised during the discussions, including intolerance to and discrimination against people with genetic disabilities; societal pressure and the 'slippery slope' of PGD were raised during the discussions. This study also highlights participants' legal standpoint, and major issues regarding PGD in relation to the accuracy of diagnosis. At the social policy level, considerations are given to access as well as the impact of this technology on families, women and physicians. Given these different perceptions of the use of PGD, and its implications and conflicts, policies and regulations of the use of PGD have to be dealt with on a case-by-case basis while taking into consideration of the risk-benefit balance, since its application will impact the lives of so many people in the society.

  5. BLOCKADE OF PGE2, PGD2 RECEPTORS CONFERS PROTECTION AGAINST PREPATENT SCHISTOSOMIASIS MANSONI IN MICE.

    Science.gov (United States)

    Abdel-Ghany, Rasha; Rabia, Ibrahim; El-Ahwany, Eman; Saber, Sameh; Gamal, Rasha; Nagy, Faten; Mahmoud, Olaa; Hamad, Rabab Salem; Barakat, Walled

    2015-12-01

    Schistosomiasis is a chronic disease with considerable social impact. Despite the availability of affordable chemotherapy, drug treatment has not significantly reduced the overall number of disease cases. Among other mechanisms, the parasite produces PGE2 and PGD2 to evade host immune defenses. To investigate the role of PGE2 and PGD2 in schistosomiasis, we evaluated the effects of L-161,982, Ah6809 (PGE2 receptor antagonists alone of combined with each other) and MK-0524 (PGD2 receptor antagonist) during prepatent Schistosoma mansoni infection. Drugs were administered intraperitoneally an hour before and 24 hours after infection of C57BL/6 mice with 100 Schistosoma mansoni cercariae. L-161,982, Ah6809, their combination and MK-0524 caused partial protection against pre-patent S. mansoni infection which was mediated by biasing the immune response towards Th1 phenotype. These results showed that blockade of PGE2 and PGD2 receptors confers partial protection against pre-patent S. mansoni infection in mice and that they may be useful as adjunctive therapy to current anti-schistosomal drugs or vaccines.

  6. Recurrent miscarriage in translocation carriers: no differences in clinical characteristics between couples who accept and couples who decline PGD.

    Science.gov (United States)

    De Krom, G; Arens, Y H J M; Coonen, E; Van Ravenswaaij-Arts, C M A; Meijer-Hoogeveen, M; Evers, J L H; Van Golde, R J T; De Die-Smulders, C E M

    2015-02-01

    Do clinical characteristics of recurrent miscarriage couples with a chromosomal abnormality and who opt for PGD differ from couples that decline PGD after extensive genetic counselling? No differences in clinical characteristics are identified between recurrent miscarriage couples carrying a structural chromosomal abnormality who opt for PGD compared with those that decline PGD after extensive genetic counselling. Couples who have experienced two or more miscarriages (recurrent miscarriage) are at increased recurrence risk if one of the partners carries a structural chromosomal abnormality. PGD can be offered to avoid (another) miscarriage or pregnancy termination when (invasive) prenatal diagnosis shows an abnormal result. To date, no reports are available that describe reproductive decision-making after genetic counselling on PGD in these specific couples. Retrospective cohort study of 294 couples carrying a structural chromosomal abnormality seeking genetic counselling on PGD between 1996 and 2012. Participants were recurrent miscarriage couples carrying a structural chromosomal abnormality. They had been referred for genetic counselling to the only national licensed PGD centre. Clinical characteristics analysed included couple associated characteristics, characteristics concerning reproductive history and external characteristics such as type of physician that referred the couple for genetic counselling and the clinical geneticist performing the counselling on PGD. Of 294 couples referred for counselling on PGD, 26 were not accepted because they did not meet the criteria for IVF-PGD. The remaining cohort of 268 couples consisted of two-thirds female and one-third male carriers. Main PGD indications were reciprocal translocations (83.9%) and Robertsonian translocations (16.7%). Following genetic counselling, 76.9% of included couples chose PGD as their reproductive option, the others declined PGD. Reproductive choice is not influenced by sex of the translocation

  7. Platelet transfusion.

    Science.gov (United States)

    1998-01-01

    The statement printed below was agreed at a consensus conference on platelet transfusion organised by the Royal College of Physicians of Edinburgh and held in Edinburgh in November 1997. We publish this statement at the request of the organising committee to bring it to the attention of physicians who do not read the haematological literature. The statement will also appear in the British Journal of Haematology in 1998 with the scientific evidence upon which it is based.

  8. Saving or Subordinating Life? Popular Views in Israel and Germany of Donor Siblings Created through PGD.

    Science.gov (United States)

    Raz, Aviad; Schües, Christina; Wilhelm, Nadja; Rehmann-Sutter, Christoph

    2017-06-01

    To explore how cultural beliefs are reflected in different popular views of pre-implantation genetic diagnosis for human leukocyte antigen match (popularly known as "savior siblings"), we compare the reception and interpretations, in Germany and Israel, of the novel/film My Sister's Keeper. Qualitative analysis of reviews, commentaries and posts is used to classify and compare normative assessments of PGD for HLA and how they reproduce, negotiate or oppose the national policy and its underlying cultural and ethical premises. Four major themes emanated from the comparison: loss of self-determination and autonomy; loss of dignity through instrumentalization; eugenics and euthanasia; and saving life. In both countries, most commentaries represented a dominant position, with a few negotiated positions. We also highlight the decoding of a relatively less explored bioethical aspect of My Sister's Keeper's narrative, namely the meaning of euthanasia. We conclude by discussing how the findings relate to attempts of providing cultural explanations for the regulation of HLA-PGD.

  9. The embryo as moral work object: PGD/IVF staff views and experiences

    OpenAIRE

    Ehrich, Kathryn; Williams, Clare; Farsides, Bobbie

    2008-01-01

    Copyright @ 2008 the authors. This article is available in accordance with the Creative Commons Deed, Attribution 2.5, see http://creativecommons.org/licenses/by-nc-nd/2.5/deed.en_CA. We report on one aspect of a study that explored the views and experiences of practitioners and scientists on social, ethical and clinical dilemmas encountered when working in the field of preimplantation genetic diagnosis (PGD) for serious genetic disorders. The study produced an ethnography based on observ...

  10. Cultural Concerns when Counseling Orthodox Jewish Couples for Genetic Screening and PGD.

    Science.gov (United States)

    Grazi, Richard V; Wolowelsky, Joel B

    2015-12-01

    There is a spectrum of attitudes within the Orthodox Jewish community towards genetic testing and PGD. Increased understanding of the belief systems of the Orthodox Jewish population will enhance the genetic counselors' ability to better serve this unique group of patients. By improving cultural competence, genetic counselors can help patients choose the testing options that they deem appropriate, while simultaneously respecting the patient's belief system.

  11. Preimplantation Genetic Diagnosis (PGD) for Monogenic Disorders: the Value of Concurrent Aneuploidy Screening.

    Science.gov (United States)

    Goldman, Kara N; Nazem, Taraneh; Berkeley, Alan; Palter, Steven; Grifo, Jamie A

    2016-12-01

    Pre-implantation genetic diagnosis (PGD) has changed the landscape of clinical genetics by helping families reduce the transmission of monogenic disorders. However, given the high prevalence of embryonic aneuploidy, particularly in patients of advanced reproductive age, unaffected embryos remain at high risk of implantation failure or pregnancy loss due to aneuploidy. 24-chromosome aneuploidy screening has become widely utilized in routine in vitro fertilization (IVF) to pre-select embryos with greater pregnancy potential, but concurrent 24-chromosome aneuploidy screening has not become standard practice in embryos biopsied for PGD. We performed a retrospective cohort study of patients who underwent PGD with or without 24-chromosome aneuploidy screening to explore the value of concurrent screening. Among the PGD + aneuploidy-screened group (n = 355 blastocysts), only 25.6 % of embryos were both Single Gene Disorder (SGD)-negative (or carriers) and euploid; thus the majority of embryos were ineligible for transfer due to the high prevalence of aneuploidy. Despite a young mean age (32.4 ± 5.9y), 49.9 % of Blastocysts were aneuploid. The majority of patients (53.2 %) had ≥1 blastocyst that was Single Gene Disorder (SGD)-unaffected but aneuploid; without screening, these unaffected but aneuploid embryos would likely have been transferred resulting in implantation failure, pregnancy loss, or a pregnancy affected by chromosomal aneuploidy. Despite the transfer of nearly half the number of embryos in the aneuploidy-screened group (1.1 ± 0.3 vs. 1.9 ± 0.6, p aneuploidy screening when performed concurrently with PGD provides valuable information for embryo selection, and notably improves single embryo transfer rates.

  12. PGD gender selection for non-Mendelian disorders with unequal sex incidence.

    Science.gov (United States)

    Amor, David J; Cameron, Carolyn

    2008-04-01

    Preimplantation genetic diagnosis (PGD) was originally developed for couples whose potential offspring were at risk of severe Mendelian disorders, but has since been extended to other indications. One possible use of PGD is to perform gender selection for couples whose offspring are at increased risk of disorders that do not follow Mendelian inheritance, but which are substantially more common in one sex than another (unequal sex incidence). Here, we examine the clinical and ethical issues to be considered prior to offering PGD gender selection to reduce the risk of a child being affected by a non-Mendelian condition with unequal sex incidence. Factors to be considered include: the risk that a child of either sex will be affected by the condition; the overall reduction in risk provided by gender selection and the potential harms of the procedure. Consideration should also be given to the interests of the family and the child to be born, the seriousness of the condition and the couple's procreative autonomy. To illustrate these issues we use the example of autism, a non-Mendelian disorder that is considerably more common in males than in females.

  13. Choosing embryos: ethical complexity and relational autonomy in staff accounts of PGD.

    Science.gov (United States)

    Ehrich, Kathryn; Williams, Clare; Farsides, Bobbie; Sandall, Jane; Scott, Rosamund

    2007-11-01

    The technique of preimplantation genetic diagnosis (PGD) is commonly explained as a way of checking the genes of embryos produced by IVF for serious genetic diseases. However, complex accounts of this technique emerged during ethics discussion groups held for PGD staff. These form part of a study exploring the social processes, meanings and institutions that frame and produce 'ethical problems' for practitioners, scientists and others working in the specialty of PGD in the UK. Two 'grey areas' raised by staff are discussed in terms of how far staff are, or in the future may be, able to support autonomous choices of women/couples: accepting 'carrier' embryos within the goal of creating a 'healthy' child; and sex selection of embryos for social reasons. These grey areas challenged the staff's resolve to offer individual informed choice, in the face of their awareness of possible collective social effects that might ensue from individual choices. We therefore argue that these new forms of choice pose a challenge to conventional models of individual autonomy used in UK genetic and reproductive counselling, and that 'relational autonomy' may be a more suitable ethical model to describe the ethical principles being drawn on by staff working in this area.

  14. Challenges, Dilemmas and Factors Involved in PGD Decision-Making: Providers' and Patients' Views, Experiences and Decisions.

    Science.gov (United States)

    Klitzman, Robert

    2017-12-16

    Providers and patients are considering and pursuing PGD for ever-more conditions, but questions arise concerning how they make, view and experience these decisions, and what challenges they may face. Thirty-seven in-depth semi-structured interviews were conducted (with 27 IVF providers and 10 patients). Patients and providers struggled with challenges and dilemmas about whether to pursue PGD in specific cases, and how to decide. Respondents varied in how they viewed, experienced and made these choices, and for which conditions to pursue PGD (from lethal, childhood-onset conditions to milder, treatable, or adult-onset disorders). Several factors were involved, including differences in gene penetrance, predictability, and phenotypic expression, and disease severity, age of onset, treatability, stigma and degree of disability. Providers and patients face questions regarding possibilities of screening for more than one condition in one set of embryos, and limitations of PGD (e.g., inaccurate results). Characteristics of providers (e.g., amount of PGD experience, understandings of genetics, and use of genetic counselors), and of patients (e.g., related to broader moral and social attitudes) can also affect these decisions. These data, the first to examine several key questions concerning PGD, suggest that providers and patients confront several dilemmas. These findings have critical implications for future practice, guidelines, education and research.

  15. PGD2 stimulates osteoprotegerin synthesis via AMP-activated protein kinase in osteoblasts: Regulation of ERK and SAPK/JNK.

    Science.gov (United States)

    Kainuma, Shingo; Tokuda, Haruhiko; Kuroyanagi, Gen; Yamamoto, Naohiro; Ohguchi, Reou; Fujita, Kazuhiko; Matsushima-Nishiwaki, Rie; Kozawa, Osamu; Otsuka, Takanobu

    2015-10-01

    AMP-activated protein kinase (AMPK), a key enzyme sensing cellular energy metabolism, is currently known to regulate multiple metabolic pathways. Osteoprotegerin plays a pivotal role in the regulation of bone metabolism by inhibiting osteoclast activation. We have previously reported that prostaglandin D2 (PGD2) stimulates the synthesis of osteoprotegerin through the activation of p38 mitogen-activated protein (MAP) kinase, p44/p42 MAP kinase and stress-activated protein kinase/c-Jun N-terminal kinase (SAPK/JNK) in osteoblast-like MC3T3-E1 cells. On the basis of these findings, we herein investigated the implication of AMPK in PGD2-stimulated osteoprotegerin synthesis in these cells. PGD2 induced the phosphorylation of AMPKα (Thr-172) and AMPKβ (Ser-108), and the phosphorylation of acetyl-coenzyme A carboxylase, a direct AMPK substrate. Compound C, an AMPK inhibitor, which suppressed the phosphorylation of acetyl-coenzyme A carboxylase, significantly attenuated both the release and the mRNA levels of osteoprotegerin stimulated by PGD2. The PGD2-induced phosphorylation of p44/p42 MAP kinase and SAPK/JNK but not p38 MAP kinase were markedly inhibited by compound C. These results strongly suggest that AMPK regulates the PGD2-stimulated osteoprotegerin synthesis at a point upstream of p44/p42 MAP kinase and SAPK/JNK in osteoblasts. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. Dealing with treatment and transfer requests: how PGD-professionals discuss ethical challenges arising in everyday practice.

    Science.gov (United States)

    Soto-Lafontaine, Melisa; Dondorp, Wybo; Provoost, Veerle; de Wert, Guido

    2017-10-28

    How do professionals working in pre-implantation genetic diagnosis (PGD) reflect upon their decision making with regard to ethical challenges arising in everyday practice? Two focus group discussions were held with staff of reproductive genetic clinics: one in Utrecht (The Netherlands) with PGD-professionals from Dutch PGD-centres and one in Prague (Czech Republic) with PGD-professionals working in centres in different European countries. Both meetings consisted of two parts, exploring participants' views regarding (1) treatment requests for conditions that may not fulfill traditional indications criteria for PGD, and (2) treatment and transfer requests involving welfare-of-the-child considerations. There was general support for the view that people who come for PGD will have their own good reasons to consider the condition they wish to avoid as serious. But whereas PGD-professionals in the international group tended to stress the applicants' legal right to eventually have the treatment they want (whatever the views of the professional), participants in the Dutch group sketched a picture of shared decision-making, where professionals would go ahead with treatment in cases where they are able to understand the reasonableness of the request in the light of the couple's reproductive history or family experience. In the international focus group there was little support for guidance stating that welfare-of-the child considerations should be taken into account. This was different in the Dutch focus group, where shared decision-making also had the role of reassuring professionals that applicants had adequately considered possible implications for the welfare of the child.

  17. Selective neutrality of 6PGD allozymes in E. coli and the effects of genetic background.

    Science.gov (United States)

    Dykhuizen, D; Hartl, D L

    1980-12-01

    We have used gluconate-limited chemostats to study selective differences between isogenic strains of Escherichia coli K12 into which four naturally occurring alleles coding for allozymes of 6-phosphogluconate dehydrogenase (6PGD) had been transferred. The limit of detectability of selection with our procedures is a selection coefficient of 0.5%. In the normal E. coli K12 genetic background, all alleles are selectively neutral or nearly neutral. The absence of detectable selection does, however, depend on genetic background and on such environmental factors as cell density. In a genetic background containing a mutation that cuts off the alternative metabolic route for 6-phosphogluconate, selection between allozymes can be detected, and the selection is in the direction expected from the measured apparent Km values of the allozymes. Even when the alternative metabolic route is not blocked by mutation, one of the 6PGD allozymes has a detrimental, but density-dependent, interaction with a mutation conferring resistance to bacteriophage T5. In all cases, the observed selection is due to the allozymes themselves (or to associated regulatory elements), as the selection disappears when the chemostats are limited by a different carbon source (ribose plus succinate). Nevertheless, the four alleles do seem to be selectively neutral or nearly neutral in the normal E. coli K12 genetic background. Moreover, the distribution of allele frequencies in natural populations of E. coli is in accord with the expectations of selective neutrality.

  18. The embryo as moral work object: PGD/IVF staff views and experiences.

    Science.gov (United States)

    Ehrich, Kathryn; Williams, Clare; Farsides, Bobbie

    2008-07-01

    We report on one aspect of a study that explored the views and experiences of practitioners and scientists on social, ethical and clinical dilemmas encountered when working in the field of preimplantation genetic diagnosis (PGD) for serious genetic disorders. The study produced an ethnography based on observation, interviews and ethics discussion groups with staff from two PGD/IVF Units in the UK. We focus here on staff perceptions of work with embryos that entails disposing of 'affected' or 'spare' embryos or using them for research. A variety of views were expressed on the 'embryo question' in contrast to polarised media debates. We argue that the prevailing policy acceptance of destroying affected embryos, and allowing research on embryos up to 14 days leaves some staff with rarely reported, ambivalent feelings. Staff views are under-researched in this area and we focus on how they may reconcile their personal moral views with the ethical framework in their field. Staff construct embryos in a variety of ways as 'moral work objects'. This allows them to shift attention between micro-level and overarching institutional work goals, building on Casper's concept of 'work objects' and focusing on negotiation of the social order in a morally contested field.

  19. Religious Scholars' Attitudes and Views on Ethical Issues Pertaining to Pre-Implantation Genetic Diagnosis (PGD) in Malaysia.

    Science.gov (United States)

    Olesen, A; Nor, S N; Amin, L

    2016-09-01

    Pre-Implantation Genetic Diagnosis (PGD) represents the first fusion of genomics and assisted reproduction and the first reproductive technology that allows prospective parents to screen and select the genetic characteristics of their potential offspring. However, for some, the idea that we can intervene in the mechanisms of human existence at such a fundamental level can be, at a minimum, worrying and, at most, repugnant. Religious doctrines particularly are likely to collide with the rapidly advancing capability for science to make such interventions. This paper focuses on opinions and arguments of selected religious scholars regarding ethical issues pertaining to PGD. In-depth interviews were conducted with religious scholars from three different religious organizations in the Klang Valley, Malaysia. Findings showed that Christian scholars are very sceptical of the long-term use of PGD because of its possible effect on the value of humanity and the parent-children relationship. This differs from Islamic scholars, who view PGD as God-given knowledge in medical science to further help humans understand medical genetics. For Buddhist scholars, PGD is considered to be new medical technology that can be used to save lives, avoid suffering, and bring happiness to those who need it. Our results suggest that it is important to include the opinions and views of religious scholars when it comes to new medical technologies such as PGD, as their opinions will have a significant impact on people from various faiths, particularly in a multi-religious country like Malaysia where society places high value on marital relationships and on the traditional concepts of family.

  20. PGD for the m.14487 T>C mitochondrial DNA mutation resulted in the birth of a healthy boy.

    Science.gov (United States)

    Sallevelt, Suzanne C E H; Dreesen, Joseph C F M; Drüsedau, Marion; Hellebrekers, Debby M E I; Paulussen, Aimee D C; Coonen, Edith; van Golde, Ronald J T; Geraedts, Joep P M; Gianaroli, Luca; Magli, Maria C; Zeviani, Massimo; Smeets, Hubert J M; de Die-Smulders, Christine E M

    2017-03-01

    We report on the first PGD performed for the m.14487 T>C mitochondrial DNA (mtDNA) mutation in the MT-ND6 gene, associated with Leigh syndrome. The female carrier gave birth to a healthy baby boy at age 42. This case adds to the successes of PGD for mtDNA mutations. © The Author 2017. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  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. Media debates and 'ethical publicity' on social sex selection through preimplantation genetic diagnosis (PGD) technology in Australia.

    Science.gov (United States)

    Whittaker, Andrea

    2015-01-01

    This paper offers a critical discourse analysis of media debate over social sex selection in the Australian media from 2008 to 2014. This period coincides with a review of the National Health and Medical Research Council's Ethical Guidelines on the Use of Assisted Reproductive Technology in Clinical Practice and Research (2007), which underlie the regulation of assisted reproductive clinics and practice in Australia. I examine the discussion of the ethics of pre-implatation genetic diagnosis (PGD) within the media as 'ethical publicity' to the lay public. Sex selection through PGD is both exemplary of and interconnected with a range of debates in Australia about the legitimacy of certain reproductive choices and the extent to which procreative liberties should be restricted. Major themes emerging from media reports on PGD sex selection in Australia are described. These include: the spectre of science out of control; ramifications for the contestation over the public funding of abortion in Australia; private choices versus public authorities regulating reproduction; and the ethics of travelling overseas for the technology. It is concluded that within Australia, the issue of PGD sex selection is framed in terms of questions of individual freedom against the principle of sex discrimination - a principle enshrined in legislation - and a commitment to publically-funded medical care.

  3. ESHRE PGD Consortium data collection V: Cycles from January to December 2002 with pregnancy follow-up to October 2003

    NARCIS (Netherlands)

    Harper, J. C.; Boelaert, K.; Geraedts, J.; Harton, G.; Kearns, W. G.; Moutou, C.; Muntjewerff, N.; Repping, S.; SenGupta, S.; Scriven, P. N.; Traeger-Synodinos, J.; Vesela, K.; Wilton, L.; Sermon, K. D.

    2006-01-01

    The fifth report of the ESHRE PGD Consortium is presented (data collection V). For the first time, the cycle data were collected for one calendar year (2002) in the following October, so that data collection was complete for pregnancies and babies. The data were collected using a Filemaker Pro

  4. Preimplantation genetic diagnosis (PGD) according to medical ethics and medical law.

    Science.gov (United States)

    Lutz, Emine Elif Vatanoğlu

    2012-01-01

    Assisted reproductive techniques not only nourish great and sometimes illusive hopes of couples who yearn for babies, but also spark new debates by reversing opinions, beliefs and values. Applications made to infertility clinics are increasing due to the influences such as broadcasts made by the media concerning assisted reproductive techniques and other infertility treatments, increase in the knowledge that people have about these problems, late marriages and postponement of childbearing age owing to sociological changes. Pre-implantation genetic diagnosis (PGD) is a technique applied to couples who are known to carry genetic diseases or who have children with genetic diseases. This technique is conducted by doctors in Turkey for its important contribution to decreasing the risk of genetic diseases and in order to raise healthy generations. In this paper, the general ethical debates and the legal situation in Turkey will be discussed.

  5. Separated representations and PGD-based model reduction fundamentals and applications

    CERN Document Server

    Ladevèze, Pierre

    2014-01-01

    The papers in this volume start with a description of  the construction of reduced models through a review of Proper Orthogonal Decomposition (POD) and reduced basis models, including their mathematical foundations and some challenging applications, then followed by a description of a  new generation of simulation strategies based on the use of separated representations (space-parameters, space-time, space-time-parameters, space-space,…), which have led to what is known as Proper Generalized Decomposition (PGD) techniques. The models can be enriched by treating parameters as additional coordinates, leading to fast and inexpensive online calculations based on richer offline parametric solutions. Separated representations are analyzed in detail in the course, from their mathematical foundations to their most spectacular applications. It is also shown how such an approximation could evolve into a new paradigm in computational science, enabling one to circumvent various computational issues in a vast array of...

  6. On the use of PGD for optimal control applied to automated fibre placement

    Science.gov (United States)

    Bur, N.; Joyot, P.

    2017-10-01

    Automated Fibre Placement (AFP) is an incipient manufacturing process for composite structures. Despite its concep-tual simplicity it involves many complexities related to the necessity of melting the thermoplastic at the interface tape-substrate, ensuring the consolidation that needs the diffusion of molecules and control the residual stresses installation responsible of the residual deformations of the formed parts. The optimisation of the process and the determination of the process window cannot be achieved in a traditional way since it requires a plethora of trials/errors or numerical simulations, because there are many parameters involved in the characterisation of the material and the process. Using reduced order modelling such as the so called Proper Generalised Decomposition method, allows the construction of multi-parametric solution taking into account many parameters. This leads to virtual charts that can be explored on-line in real time in order to perform process optimisation or on-line simulation-based control. Thus, for a given set of parameters, determining the power leading to an optimal temperature becomes easy. However, instead of controlling the power knowing the temperature field by particularizing an abacus, we propose here an approach based on optimal control: we solve by PGD a dual problem from heat equation and optimality criteria. To circumvent numerical issue due to ill-conditioned system, we propose an algorithm based on Uzawa's method. That way, we are able to solve the dual problem, setting the desired state as an extra-coordinate in the PGD framework. In a single computation, we get both the temperature field and the required heat flux to reach a parametric optimal temperature on a given zone.

  7. Rhesus monkey platelets

    Energy Technology Data Exchange (ETDEWEB)

    Harbury, C.B.

    1986-03-01

    The purpose of this abstract is to describe the adenine nucleotide metabolism of Rhesus monkey platelets. Nucleotides are labelled with /sup 14/C-adenine and extracted with EDTA-ethanol (EE) and perchlorate (P). Total platelet ATP and ADP (TATP, TADP) is measured in the Holmsen Luciferase assay, and expressed in nanomoles/10/sup 8/ platelets. TR=TATP/TADP. Human platelets release 70% of their TADP, with a ratio of released ATP/ADP of 0.7. Rhesus platelets release 82% of their TADP, with a ratio of released ATP/ADP of 0.33. Thus, monkey platelets contain more ADP than human platelets. Thin layer chromatography of EE gives a metabolic ratio of 11 in human platelets and 10.5 in monkey platelets. Perchlorate extracts metabolic and actin bound ADP. The human and monkey platelets ratios were 5, indicating they contain the same proportion of actin. Thus, the extra ADP contained in monkey platelets is located in the secretory granules.

  8. Developmental neuropsychological assessment of 4- to 5-year-old children born following Preimplantation Genetic Diagnosis (PGD): A pilot study.

    Science.gov (United States)

    Sacks, Gilat Chaya; Altarescu, Gheona; Guedalia, Judith; Varshaver, Irit; Gilboa, Tal; Levy-Lahad, Ephrat; Eldar-Geva, Talia

    2016-01-01

    The purpose of this pilot study was to evaluate developmental neuropsychological profiles of 4- to 5-year-old children born after Preimplantation Genetic Diagnosis (PGD). Twenty-seven participants received a neurological examination and a battery of neuropsychological assessments including Wechsler Preschool & Primary Scale of Intelligence - Third Edition (WPPSI-III; cognitive development), Preschool Language Scale, Fourth Edition (PLS-4; language development), Wide Range Assessment of Visual Motor Abilities (visual motor abilities), Childhood Autism Rating Scales II (a screening test for autistic spectrum disorders), and the Miles ABC Test (ocular dominance). Parental questionnaires included the Behavior Rating Inventory of Executive Function Preschool Version (BRIEF-P; executive function), Child Behavior Checklist (CBCL) and the Carey Temperament Scales Behavioral Style Questionnaire (socioemotional development and temperament), and the Vineland Adaptive Behavior Scales, Interview Edition, Second Edition (general adaptive behavior). Subjects' tests results were compared to each test's norms. Children born after PGD demonstrated scores within the normal or above-normal ranges for all developmental outcomes (mean ± SD): WPPSI-III-VIQ 107.4 ± 14.4 (p = .013), PLS-4-Total 113.2 ± 12.4, p < .001), CBCL-Total 41.1 ± 8.6 (p < .001), BRIEF-P-Global Executive Composite 44.8 ± 9.5 (p = .009). Twelve (44%) of the PGD children had a significant difference between their VIQ and PIQ scores (compared to 27% in the general population). One subject was found to show possible signs of autistic spectrum disorder, although a family history of autism was noted. In conclusion, in this pilot study, children assessed at age 4-5 years and conceived after PGD displayed developmental neuropsychological outcomes within normal limits as compared to their chronologic peers. A larger study is needed to evaluate and follow the neuropsychological development of children born after PGD.

  9. 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 patients...... who received a single series of blood transfusions. They received mostly saline-adenine-glucose+mannitol red blood cell components (poor in leukocytes and platelets) in connection with cardiac surgery. Platelet-specific antibodies were detected with the platelet ELISA and the monoclonal...... immunization. CONCLUSION: There was a low incidence of platelet-specific antibodies after one series of blood transfusions in this group of patients. This is similar to the results of some previous studies in multiply transfused patients, but not with those of others who found a higher incidence....

  10. Effect of PGD2 on middle meningeal artery and mRNA expression profile of L-PGD2 synthase and DP receptors in trigeminovascular system and other pain processing structures in rat brain

    DEFF Research Database (Denmark)

    Sekeroglu, Aysegül; Jacobsen, Julie Mie; Jansen-Olesen, Inger

    2017-01-01

    and PGI2 dilate the middle meningeal artery (MMA), and mRNA for PGE2 and PGI2 receptors is present in rat trigeminovascular system (TVS) and in the brain structures associated with pain. In the present study, we have characterized the dilatory effect of PGD2 on rat MMA and studied the relative m....... Results PGD2 infusion evoked a dose-dependent dilation of the rat MMA. The calculated mean pED50 value was 5.23 ± 0.10 and Emax was 103 ± 18% (n = 5). MK-0524 significantly (∼61%, p MMA. mRNA for the DP1, DP2 and L-PGDS were expressed differentially in all...... tested tissues. DP1 receptor mRNA was expressed maximally in trigeminal ganglion (TG) and in cervical dorsal root ganglion (DRG). Conclusions High expression of DP1 mRNA in the TG and DRG suggest that PGD2 might play a role in migraine pathophysiology. Activation of the DP1 receptor in MMA was mainly...

  11. Social welfare, genetic welfare? Boundary-work in the IVF/PGD clinic.

    Science.gov (United States)

    Ehrich, Kathryn; Williams, Clare; Scott, Rosamund; Sandall, Jane; Farsides, Bobbie

    2006-09-01

    Through the lens of the 'welfare of the child' assessment, this paper explores how staff working in the area of in vitro fertilisation and preimplantation genetic diagnosis (IVF/PGD) balance reflexive relations of legitimacy and accountability between the public and private spheres, and between medicine, the citizen and the state. The wider research of which this analysis is a part uses multiple methods to study two National Health Service Assisted Conception Units in England. Research methods used included observation clinics and interviews with staff from a range of disciplines. We illustrate how the staff reveal tensions between their views that the welfare of the child assessment can be seen as intrusive and discriminatory, and on the other hand that medical intervention in reproduction should be socially and professionally accountable. These tensions can be understood sociologically in terms of a gradual movement from socially based solutions to fertility problems and disabilities, towards a biomedical, and arguably genetically oriented worldview of such problems. Rather than being viewed as discrete, these two orientations should be seen as indicating an emergent direction of travel along a continuum, with elements of both being present in the accounts. We argue that consideration of the welfare of the child involves staff in ethical boundary-work across the two orientations and between the accountabilities and responsibilities of healthcare professionals, individuals and the state.

  12. Assisted reproductive technology (ART) cumulative live birth rates following preimplantation genetic diagnosis for aneuploidy (PGD-A) or morphological assessment of embryos: A cohort analysis.

    Science.gov (United States)

    Lee, Evelyn; Chambers, Georgina Mary; Hale, Lyndon; Illingworth, Peter; Wilton, Leeanda

    2017-12-27

    Preimplantation genetic diagnosis for aneuploidy (PGD-A) for all 24 chromosomes improves implantation and clinical pregnancy rates per single assisted reproductive technology (ART) cycle. However, there is limited data on the live-birth rate of PGD-A over repeated cycles. To assess the cumulative live-birth rates (CLBR) of PGD-A compared with morphological assessment of embryos of up to three 'complete ART cycles' (fresh plus frozen/thaw cycles) in women aged 37 years or older. A retrospective cohort study of ART treatments undertaken by ART-naïve women at a large Australian fertility clinic between 2011 and 2014. Cohorts were assigned based on the embryo selection method used in their first fresh cycle [PGD-A, n = 110 women (PGD-A group); morphological assessment of embryos, n = 1983 women (control group)]. CLBR, time to clinical pregnancy and cycles needed to achieve a live birth were measured over multiple cycles. Compared to the control group, the PGD-A group achieved a higher per cycle live-birth rate (14.47% vs 9.12%, P ART cycles', the CLBR was comparable for the two groups (30.90% vs 26.77%, P = 0.34). This is the first study to assess the effectiveness of PGD-A over multiple ART cycles. These real-world findings suggest that PGD-A leads to better outcomes than using morphological assessment alone in women of advanced maternal age. © 2017 The Royal Australian and New Zealand College of Obstetricians and Gynaecologists.

  13. 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

  14. 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...

  15. 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...

  16. 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....

  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 patients...... who received a single series of blood transfusions. They received mostly saline-adenine-glucose+mannitol red blood cell components (poor in leukocytes and platelets) in connection with cardiac surgery. Platelet-specific antibodies were detected with the platelet ELISA and the monoclonal...... (17.9%), of whom 18 (15.4%) had had no detectable antibodies before transfusion. There was a positive correlation between the transfused load of immunogenic materials and the frequency of alloimmunization against HLA antigens. In one third of the immunized patients, there was no history of previous...

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

    DEFF Research Database (Denmark)

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

    2017-01-01

    –IIIa, P-selectin and CD63 after addition of agonists: collagen-related peptide, thrombin receptor-activating peptide (TRAP), and ADP. Results The platelet aggregation assay showed a low intraserial coefficient of variation of ≤ 3%. Similar results were obtained for platelet-rich plasma and isolated......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...

  19. 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

  20. 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

  1. 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

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

    African Journals Online (AJOL)

    ... platelet volume (MPV) is a laboratory marker associated with platelet function and activity. Increased MPV in thromboembolic disease is reflected as an important risk factor. The aim of this study was to compare the MPV and mean platelet volume/platelet count (MPV/PC) ratio between ischemic cerebrovascular stroke and ...

  3. Platelet Function Tests

    Science.gov (United States)

    ... vessel and bleeding begins, platelets are the first elements to help to stop bleeding. They do so ... for more information on drugs, drug ingredients, and brand names.) However, do not stop taking your medications ...

  4. 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

  5. Human platelet antigens - 2013.

    Science.gov (United States)

    Curtis, B R; McFarland, J G

    2014-02-01

    To date, 33 human platelet alloantigens (HPAs) have been identified on six functionally important platelet glycoprotein (GP) complexes and have been implicated in alloimmune platelet disorders including foetal and neonatal alloimmune thrombocytopenia (FNAIT), posttransfusion purpura (PTP) and multitransfusion platelet refractoriness (MPR). The greatest number of recognized HPA (20 of 33) resides on the GPIIb/IIIa complex, which serves as the receptor for ligands important in mediating haemostasis and inflammation. These include HPA-1a, the most commonly implicated HPA in FNAIT and PTP in Caucasian populations. Other platelet GP complexes, GPIb/V/IX, GPIa/IIa and CD109, express the remaining 13 HPAs. Of the recognized HPAs, 12 occur as six serologically and genetically defined biallelic 'systems' where the -a form designates the higher frequency allele and the -b form, the lower. Twenty-one other HPAs are low-frequency or rare antigens for which postulated higher frequency -a alleles have not yet been identified as antibody specificities. In addition to the HPA markers, platelets also express ABO and human leucocyte antigen (HLA) antigens; antibodies directed at the former are occasionally important in FNAIT, and to the latter, in MPR. © 2013 International Society of Blood Transfusion.

  6. Attitudes of Chinese couples in Hong Kong regarding using preimplantation genetic diagnosis (PGD) and human leukocyte antigens (HLA) typing to conceive a 'Saviour Child'.

    Science.gov (United States)

    Hui, Edwin C; Chan, Carina; Liu, Athena; Chow, Kathy

    2009-06-01

    To investigate Hong Kong couples' attitudes and concerns about using preimplantation genetic diagnosis (PGD) and human leukocyte antigens (HLA) typing to conceive a disease-free and tissue-compatible 'Saviour Child (SC)' to save an afflicted sibling. Two cohorts of Chinese couples, one with natural pregnancies and the other receiving in vitro fertilization (IVF) services, were studied using a structured questionnaire. Although most couples believed that embryos possess moral rights, they considered it acceptable to reproduce a donor child if it was safe for the child, and tissue transplantation was the only available treatment for the sick sibling. Most couples believed that the donor child would not suffer adverse physical or psychological effects but rather would gain positive psychological benefits, and opined that parents using PGD/HLA-typing suffer sacrificially for their children. In response to one specific question, one-third of the couples agreed to use the donor child as a lifetime organ donor and supported the use of PGD for non-medical gender selection. One-quarter were willing to reject PGD/HLA-typing because of its potential for non-medical genetic enhancement. Probably influenced by the Chinese tradition of strong familism, couples in Hong Kong generally show positive attitudes towards using PGD/HLA-typing to reproduce a 'SC' to save a sibling affected with life-threatening diseases amenable to treatment with genetically compatible tissue. (c) 2009 John Wiley & Sons, Ltd.

  7. 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

  8. 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.

  9. Platelet-activating factor (PAF) induces wheal and flare skin reactions independent of mast cell degranulation.

    Science.gov (United States)

    Krause, K; Giménez-Arnau, A; Martinez-Escala, E; Farré-Albadalejo, M; Abajian, M; Church, M K; Maurer, M

    2013-02-01

    Platelet-activating factor (PAF) causes wheal and flare responses which are abrogated by H1-antihistamines giving rise to the hypothesis that PAF-induced wheal development is secondary to histamine release from dermal mast cells. But is this hypothesis correct? Wheal and flare responses were induced by intradermal injection of PAF, codeine and histamine in 14 healthy volunteers. Dermal histamine and PGD2 contractions were measured using microdialysis. PAF, unlike histamine and codeine, did not cause a statistically significant rise in mean histamine levels with ten persons showing negligible histamine release. Codeine caused a significant but variable histamine release, ranging from 29 to 282 ng/ml. Codeine, but not PAF or histamine, caused a small but statistically significant release of PGD2. Wheal and flare reactions in human skin induced by PAF are not associated with histamine release and, therefore, appear to be independent of mast cell degranulation. © 2013 John Wiley & Sons A/S. Published by Blackwell Publishing Ltd.

  10. Biology of Platelet Purinergic Receptors and Implications for Platelet Heterogeneity

    Directory of Open Access Journals (Sweden)

    Milka Koupenova

    2018-01-01

    Full Text Available Platelets are small anucleated cells present only in mammals. Platelets mediate intravascular hemostatic balance, prevent interstitial bleeding, and have a major role in thrombosis. Activation of platelet purinergic receptors is instrumental in initiation of hemostasis and formation of the hemostatic plug, although this activation process becomes problematic in pathological settings of thrombosis. This review briefly outlines the roles and function of currently known platelet purinergic receptors (P1 and P2 in the setting of hemostasis and thrombosis. Additionally, we discuss recent novel studies on purinergic receptor distribution according to heterogeneous platelet size, and the possible implication of this distribution on hemostatic function.

  11. Piperine Inhibits the Activities of Platelet Cytosolic Phospholipase A2 and Thromboxane A2 Synthase without Affecting Cyclooxygenase-1 Activity: Different Mechanisms of Action Are Involved in the Inhibition of Platelet Aggregation and Macrophage Inflammatory Response

    Directory of Open Access Journals (Sweden)

    Dong Ju Son

    2014-08-01

    Full Text Available PURPOSE: Piperine, a major alkaloid of black pepper (Piper nigrum and long pepper (Piper longum, was shown to have anti-inflammatory activity through the suppression of cyclooxygenase (COX-2 gene expression and enzyme activity. It is also reported to exhibit anti-platelet activity, but the mechanism underlying this action remains unknown. In this study, we investigated a putative anti-platelet aggregation mechanism involving arachidonic acid (AA metabolism and how this compares with the mechanism by which it inhibits macrophage inflammatory responses; METHODS: Rabbit platelets and murine macrophage RAW264.7 cells were treated with piperine, and the effect of piperine on the activity of AA-metabolizing enzymes, including cytosolic phospholipase A2 (cPLA2, COX-1, COX-2, and thromboxane A2 (TXA2 synthase, as well as its effect on AA liberation from the plasma membrane components, were assessed using isotopic labeling methods and enzyme immunoassay kit; RESULTS: Piperine significantly suppressed AA liberation by attenuating cPLA2 activity in collagen-stimulated platelets. It also significantly inhibited the activity of TXA2 synthase, but not of COX-1, in platelets. These results suggest that piperine inhibits platelet aggregation by attenuating cPLA2 and TXA2 synthase activities, rather than through the inhibition of COX-1 activity. On the other hand, piperine significantly inhibited lipopolysaccharide-induced generation of prostaglandin (PGE2 and PGD2 in RAW264.7 cells by suppressing the activity of COX-2, without effect on cPLA2; CONCLUSION: Our findings indicate that piperine inhibits platelet aggregation and macrophage inflammatory response by different mechanisms.

  12. 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.

  13. Advanced maternal age as an indication for preimplantation genetic diagnosis (PGD)--the need for more judicious application in clinically assisted reproduction.

    Science.gov (United States)

    Heng, Boon Chin

    2006-11-01

    Pre-implantation genetic diagnosis (PGD) is often recommended for routine screening of chromosomal aneuploidy in older women undergoing clinical assisted reproduction, even though its prognostic value on this group of patients is rather ambiguous. What is needed is a clear set of ethical guidelines in the marketing of this technically complex and expensive procedure to patients who are neither suffers nor carriers of serious genetic diseases. Professional counseling would be required to enable an informed decision from the patient. Differences in the prognostic value of PGD for different medical indications must be clearly presented to the patient and they must also be told that PGD is not a completely 'fool-proof' means of preventing birth defects. What may be detected are some genetic syndromes and conditions associated with cytogenetic abnormalities. The patient must be made aware that the results of previous studies have demonstrated that the overwhelming majority of chromosomally abnormal oocytes and embryos either fail to fertilize or implant, and therefore have a relatively low chance of resulting in a live birth with chromosomal defects. Statistical data, particularly the concept of relative risk must clearly be presented to the patient without exaggerating the risk of birth defects. The patient must also be rightfully informed that PGD carries a small risk of damaging the embryo, which could compromise chances of conception. PGD should be judiciously indicated for advanced maternal age in clinically assisted reproduction. Other diagnostic options that may be cheaper, and which also possess a high level of accuracy should be presented first to the patient i.e. amniocentesis, chorionic villus biopsy and ultrasonargraphy.

  14. 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.

  15. Novel aspects of platelet aggregation

    Directory of Open Access Journals (Sweden)

    Roka-Moya Y. M.

    2014-01-01

    Full Text Available The platelet aggregation is an important process, which is critical for the hemostatic plug formation and thrombosis. Recent studies have shown that the platelet aggregation is more complex and dynamic than it was previously thought. There are several mechanisms that can initiate the platelet aggregation and each of them operates under specific conditions in vivo. At the same time, the influence of certain plasma proteins on this process should be considered. This review intends to summarize the recent data concerning the adhesive molecules and their receptors, which provide the platelet aggregation under different conditions.

  16. 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...

  17. Platelets, inflammation and tissue regeneration.

    Science.gov (United States)

    Nurden, Alan T

    2011-05-01

    Blood platelets have long been recognised to bring about primary haemostasis with deficiencies in platelet production and function manifesting in bleeding while upregulated function favourises arterial thrombosis. Yet increasing evidence indicates that platelets fulfil a much wider role in health and disease. First, they store and release a wide range of biologically active substances including the panoply of growth factors, chemokines and cytokines released from a-granules. Membrane budding gives rise to microparticles (MPs), another active participant within the blood stream. Platelets are essential for the innate immune response and combat infection (viruses, bacteria, micro-organisms). They help maintain and modulate inflammation and are a major source of pro-inflammatory molecules (e.g. P-selectin, tissue factor, CD40L, metalloproteinases). As well as promoting coagulation, they are active in fibrinolysis; wound healing, angiogenesis and bone formation as well as in maternal tissue and foetal vascular remodelling. Activated platelets and MPs intervene in the propagation of major diseases. They are major players in atherosclerosis and related diseases, pathologies of the central nervous system (Alzheimers disease, multiple sclerosis), cancer and tumour growth. They participate in other tissue-related acquired pathologies such as skin diseases and allergy, rheumatoid arthritis, liver disease; while, paradoxically, autologous platelet-rich plasma and platelet releasate are being used as an aid to promote tissue repair and cellular growth. The above mentioned roles of platelets are now discussed.

  18. Aspirin-Intolerant Asthma (AIA Assessment Using the Urinary Biomarkers, Leukotriene E4 (LTE4 and Prostaglandin D2 (PGD2 Metabolites

    Directory of Open Access Journals (Sweden)

    Noritaka Higashi

    2012-01-01

    Full Text Available The clinical syndrome of aspirin-intolerant asthma (AIA is characterized by aspirin/nonsteroidal antiinflammatory drug intolerance, bronchial asthma, and chronic rhinosinusitis with nasal polyposis. AIA reactions are evidently triggered by pharmacological effect of cyclooxygenase-1 inhibitors. Urine sampling is a non-invasive research tool for time-course measurements in clinical investigations. The urinary stable metabolite concentration of arachidonic acid products provides a time-integrated estimate of the production of the parent compounds in vivo. AIA patients exhibits significantly higher urinary concentrations of leukotriene E4 (LTE4 and 1,15-dioxo-9α-hydroxy-2,3,4,5-tetranorprostan-1,20-dioic acid (tetranor-PGDM, a newly identified metabolite of PGD2, at baseline. This finding suggests the possibility that increased mast cell activation is involved in the pathophysiology of AIA even in a clinically stable condition. In addition, lower urinary concentrations of primary prostaglandin E2 and 15-epimer of lipoxin A4 at baseline in the AIA patients suggest that the impaired anti-inflammatory elements may also contribute to the severe clinical outcome of AIA. During the AIA reaction, the urinary concentrations of LTE4 and PGD2 metabolites, including tetranor-PGDM significantly and correlatively increase. It is considered that mast cell activation probably is a pathophysiologic hallmark of AIA. However, despite the fact that cyclooxygenease-1 is the dominant in vivo PGD2 biosynthetic pathway, the precise mechanism underlying the PGD2 overproduction resulting from the pharmacological effect of cyclooxygenease-1 inhibitors in AIA remains unknown. A comprehensive analysis of the urinary concentration of inflammatory mediators may afford a new research target in elucidating the pathophysiology of AIA.

  19. [Genetic polymorphism of AcP, EsD, 6-PGD and GPT in eleven ethnic groups of China].

    Science.gov (United States)

    Xu, J J; Tan, Q A; Zhao, X X; Du, R F

    1989-01-01

    The genetic polymorphism of red cell acid phosphatase (AcP), Esterase D (EsD), 6-phosphogluconate dehydrogenase (6-PGD) and Glutamic pyruvic transaminase (GPT) in eleven ethnic groups of China was studied by starch gel electrophoresis. The results of 2272 tested showed that the gene frequencies of AcPB1 in Dong, Hui, Bai, Tujia, Miao, Yi, Tibetan, Man, Yao, Hani, Buyi, etc. were 0.7835, 0.7958, 0.8137, 0.7750, 0.7624, 0.8038, 0.8075, 0.8035, 0.7725, 0.6488, 0.6896, EsD1 gene frequencies were 0.6418, 0.7315, 0.6005, 0.6025, 0.6411, 0.6411, 0.6558, 0.6305, 0.6020, 0.6023, 0.6368. 6-PGDA gene frequencies 0.9279, 0.9381, 0.9387, 0.9150, 0.9356, 0.9014, 0.7764, 0.8818, 0.9851, 0.9233, 0.9410. GPT1 gene frequencies 0.4075, 0.5367, 0.5049, 0.4824, 0.5322, 0.6106, 0.6313, 0.6400, 0.3985, 0.4930, 0.3976, respectively. In addition, some rare variants were found.

  20. 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

  1. 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

  2. Platelet scintigraphy in atherothrombotic disease

    Energy Technology Data Exchange (ETDEWEB)

    Isaka, Yoshinari (Osaka National Hospital (Japan))

    1993-01-01

    Indium-111 platelet scintigraphy for the measurement of in vivo thrombogenicity is a useful noninvasive technique with a number of applications. From 1982 to 1989, we explored clinical relevance of this method for 576 consecutive patients with atherothrombotic disease. There was a disease-related difference in the percentage of positive platelet accumulation; 85% in patients with Dacron bifurcation graft, 75% in abdominal or thoracic aneurysm, 40% in intra-cardiac thrombi, 33% in arteriosclerosis obliterans and 25% in ischemic cerebrovascular disease. Labelled platelets accumulated frequently in the lesion with severe arteriographic abnormality. Aspirin clearly inhibited platelet accumulation on carotid atheroma but the effect of ticlopidine has been less conclusive. Short-term orally active PGI[sub 2] analogue had inhibitory effects on platelet accumulation in carotid atheroma and platelet aggregability, but did not cause significant reduction in plaque size. The results suggest the usefulness of platelet scintigraphy for monitoring the thrombogenicity in various atherothrombotic diseases. It will be necessary, however, to simplify the labelling procedures and to develop a new [sup 99m]Tc-labelled thrombus imaging agent, if thrombus imaging is to be considered for more generall use for patients with atherosclerosis. (author).

  3. Leukocyte removal filtration of platelet concentrates

    International Nuclear Information System (INIS)

    Wadenvik, H.; Kutti, J.; Lindholm, A.

    1991-01-01

    111 In labelled platelets and gamma camera scintigraphy were used for the study of the platelet loss during leukocyte removal filtration of stored platelets. Two different filters were examined, Imugard IG500 and Pall PL100, and platelet pools containing varying number of platelet concentrates were filtered. It was found that a sizeable amount of the platelets was trapped within the filter. Some of the trapped platelets could be recovered by rinsing the filters with normal saline. The most appropriate rinsing volume to recover lost platelets seemed to match with the ''dead space'' volume within the filter. It is concluded that radiolabelled platelets and gamma camera scintigraphy appears to be an excellent method to investigate the dynamic events of platelet loss during leukocyte removal filtration. This technique should be well applicable for the study of technological advances in filter construction. (author)

  4. 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....

  5. 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

  6. 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.

  7. Platelet adhesion onto artificial red blood cells.

    Science.gov (United States)

    Muramatsu, N; Kondo, T

    1980-05-01

    Several kinds of polyamide microcapsules containing mammalian hemolysate were prepared by making use of the interfacial polycondensation reaction between diamines and terephthaloyl dichloride and their blood compatibility in terms of platelet adhesion was examined aiming at their ultimate clinical use as artificial red blood cells. It was found that rabbit platelets adhere onto the hemolysate-loaded microcapsules in the presence of the plasma, while no platelet adhesion takes place in the absence of the plasma. This was interpreted as indicating an important role of plasma components in platelet adhesion. Moreover, platelet adhesion was observed to be facilitated by negative charges on the surface of the hemolysate-loaded microcapsules; the more negatively the surface was charge, the more easily the platelets adhered onto the surface. Finally, the present method of assessing platelet adhesion suggested the possibility of its use for kinetic study of platelet adhesion since it allowedus to make numerical evaluation of platelet adhesion as a function of time.

  8. 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

  9. Derivation of HVR1, HVR2 and HVR3 human embryonic stem cell lines from IVF embryos after preimplantation genetic diagnosis (PGD) for monogenic disorder

    OpenAIRE

    Abdelkrim Hmadcha; Yolanda Aguilera; Maria Dolores Lozano-Arana; Nuria Mellado; Javier Sánchez; Cristina Moya; Luis Sánchez-Palazón; Jose Palacios; Guillermo Antiñolo; Bernat Soria

    2016-01-01

    From 106 human blastocyts donate for research after in vitro fertilization (IVF) and preimplantation genetic diagnosis (PGD) for monogenetic disorder, 3 human embryonic stem cells (hESCs) HVR1, HVR2 and HVR3 were successfully derived. HVR1 was assumed to be genetically normal, HVR2 carrying Becker muscular dystrophy and HVR3 Hemophilia B. Despite the translocation t(9;15)(q34.3;q14) detected in HVR2, all the 3 cell lines were characterised in vitro and in vivo as normal hESCs lines and were r...

  10. 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.

  11. Establishing biological reference intervals for novel platelet parameters (immature platelet fraction, high immature platelet fraction, platelet distribution width, platelet large cell ratio, platelet-X, plateletcrit, and platelet distribution width and their correlations among each other

    Directory of Open Access Journals (Sweden)

    Ritesh Sachdev

    2014-01-01

    Full Text Available Aims: This study aims to establish biological reference interval for novel platelet parameters. Settings and Design: A total of 945 healthy individuals, age ranges from 18 to 64 years (881 males and 64 females coming for voluntary blood donation from June to August 2012 (3 months were enrolled after exclusion of rejection criteria. Materials and Methods: The samples were assayed by running in complete blood count + reticulocyte mode on the Sysmex XE-2100 hematology analyzer and the reference interval for the population was calculated using Clinical and Laboratory Standards Institute guidelines. Statistical analysis used: Tests were performed using SPSS (Statistical Product and Service Solutions , developed by IBM corporation, version 13. Student t test and pearsons correlation analysis were also used. Results: The normal range for various parameters was platelet count: 150-520 × 10 3 /cu mm, immature platelet fraction (IPF: 0.3-8.7%, platelet distribution width (PDW: 8.3-25.0 fL, mean platelet volume (MPV: 8.6-15.5 fL, plateletcrit (PCT: 0.15-0.62%, high immature platelet fraction (H-IPF: 0.1-2.7%, platelet large cell ratio (P-LCR: 11.9-66.9% and platelet-X (PLT-X (ch: 11.0-22.0. Negative correlation was observed between platelet count (r = −0.468 to r = −0.531; P < 0.001 and PCT (r = −0.080 to r = −0.235; P < 0.05 to P < 0.001 with IPF, PDW, MPV, H-IPF, P-LCR, and platelet-X. IPF/H-IPF showed a positive correlation among them and also with PDW, MPV, P-LCR, platelet-X (r = +0.662 to r = +0.925; P < 0.001. Conclusions: These novel platelet parameters offer newer avenues in research and clinical use. Establishing biological reference interval for different platelet parameters would help determine true high and low values and help guide treatment decisions.

  12. 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

  13. Alcohol, Wine and Platelet Function

    Directory of Open Access Journals (Sweden)

    JEAN-CLAUDE RUF

    2004-01-01

    Full Text Available Epidemiological studies have demonstrated an inverse correlation between moderate wine and alcohol consumption and morbidity and mortality from coronary heart disease. The protective effect has been associated with an increase in the plasma level of HDL cholesterol, as it is well recognized that plasma HDL is inversely correlated with CHD. In addition, it has become evident that blood platelets contribute to the rate of development of atherosclerosis and CHD through several mechanisms. In recent studies it has been shown that the level of HDL cholesterol can explain only 50 % of the protective effect of alcoholic beverages; the other 50 % may be partly related to a decrease in platelet activity. This anti-platelet activity of wine is explained by ethanol but also by the polyphenolic components with which red wines are richly endowed. Several studies carried out on humans and animals have shown that wine phenolics could exert their effects by reducing prostanoid synthesis from arachidonate. In addition, it has been suggested that wine phenolics could reduce platelet activity mediated by nitric oxide. Moreover, wine phenolics increase vitamin E levels while decreasing the oxidation of platelets submitted to oxidative stress. However, a rebound phenomenon of hyperaggregability is observed after an acute alcohol consumption which is not observed with wine consumption. This protection afforded by wine has been duplicated in animals with grape phenolics added to alcohol. The rebound phenomenon may explain ischemic strokes or sudden deaths known to occur after episodes of drunkenness. It appears that wine, and wine phenolics in particular, could have a more significant inhibitory effect on platelet aggregation and could explain, in part, the hypothesis that red wine is more protective against atherosclerosis and coronary heart disease.

  14. Retrospective platelet values measurement assesment always ...

    African Journals Online (AJOL)

    Am J Clin Pathol. 1983; 80: 327-332. 3. Beth H. Shaz, Christopher D. Hillyer, Mikhail Ro- shal, and Charles S. Abrams. Chapter 133, Measurement of. Platelet Count, Mean Platelet Volume and Reticulated Platelets. 2nd edn. Transfusion Medicine and Hemostasis: Clini- cal and Laboratory Aspects. San Diego, DC: Elsevier,.

  15. 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.)

  16. Platelet aggregates and ADP-induced platelet aggregation in ...

    African Journals Online (AJOL)

    Hypertension is a condition characterized by haemodynamic vascular stress and abnormal blood flow under high pressure and it is associated with complications that are, paradoxically, thrombotic rather than haemorrhagic. Spontaneous platelet aggregation has been known to be present in hypertension which predicts ...

  17. platelet counts and mean platelet volume amongst elderly

    African Journals Online (AJOL)

    Dr Ahmed

    Sex and age differences in platelet counts were observed in the elderly subjects ... as a result of progressive reduction in haemopoietic stem cells due to exhaustion of .... apparently thrombocytopenia when count observed do not differ from those usually observed in healthy elderly subjects of the same age and sex group.

  18. Platelet count and platelet indices in women with preeclampsia

    Directory of Open Access Journals (Sweden)

    AlSheeha MA

    2016-11-01

    Full Text Available Muneera A AlSheeha,1 Rafi S Alaboudi,1 Mohammad A Alghasham,1 Javed Iqbal,2 Ishag Adam1 1Department of Obstetrics and Gynaecology, College of Medicine, Qassim University, Buriadah, 2Department of Obstetrics and Gynecology, Maternity and Children’s Hospital, Qassim, Kingdom of Saudi Arabia Background: Although the exact pathophysiology of preeclampsia is not completely understood, the utility of different platelets indices can be utilized to predict preeclampsia.Objective: 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.Setting: Qassim Hospital, Kingdom of Saudi Arabia.Design: A case–control study. Sixty preeclamptic women were the cases and an equal number of healthy pregnant women were the controls.Results: 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 248.0×103/µL for diagnosis of preeclampsia (P=0.019; the area under the ROC curve was 62.4%. Binary regression suggests that women with PC <248.010×103/µL were at higher risk of 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%.Conclusion: PC <248.010×103/µL and PC to MPV ratio 31.2 are valid predictors of preeclampsia. Keywords: preeclampsia, platelets, PDW, mean platelet

  19. 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.

  20. 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.)

  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. Calpain Activator Dibucaine Induces Platelet Apoptosis

    Directory of Open Access Journals (Sweden)

    Jun Liu

    2011-03-01

    Full Text Available Calcium-dependent calpains are a family of cysteine proteases that have been demonstrated to play key roles in both platelet glycoprotein Ibα shedding and platelet activation and altered calpain activity is associated with thrombotic thrombocytopenic purpura. Calpain activators induce apoptosis in several types of nucleated cells. However, it is not clear whether calpain activators induce platelet apoptosis. Here we show that the calpain activator dibucaine induced several platelet apoptotic events including depolarization of the mitochondrial inner transmembrane potential, up-regulation of Bax and Bak, down-regulation of Bcl-2 and Bcl-XL, caspase-3 activation and phosphatidylserine exposure. Platelet apoptosis elicited by dibucaine was not affected by the broad spectrum metalloproteinase inhibitor GM6001. Furthermore, dibucaine did not induce platelet activation as detected by P-selectin expression and PAC-1 binding. However, platelet aggregation induced by ristocetin or α-thrombin, platelet adhesion and spreading on von Willebrand factor were significantly inhibited in platelets treated with dibucaine. Taken together, these data indicate that dibucaine induces platelet apoptosis and platelet dysfunction.

  3. Platelets contain releasable coagulation factor IX antigen.

    Science.gov (United States)

    Romp, K G; Monroe, D M; Hoffman, M

    1993-12-01

    Platelets take up plasma proteins into their alpha granules. Platelet activation releases the alpha granule contents. The goal of this study was to test the hypothesis that human platelets also contain some coagulation factor IX in their alpha granules. Platelets were examined by immunofluorescence microscopy. Activated and unactivated platelets were quick frozen on to slides and dehydrated in situ to preserve optimal morphology. The slides were stained by indirect immunofluorescence for factors V and IX. Unactivated platelets showed coarsely granular staining for factor V and finely granular staining for factor IX. Staining for factor V was diffuse after activation, while staining for factor IX disappeared. Thus, the results support the conclusion that platelets contain factor IX which can be released upon activation. Immunoelectron microscopic studies were conducted to more precisely localize the site of the platelet factor IX. As expected, factor V was primarily localized in the alpha granules of unactivated platelets. By contrast, factor IX was observed both in alpha granules and diffusely in the platelet cytoplasm and membrane-bounded vesicles. After activation, staining for both factors V and IX was primarily in the open canalicular system. The physiological importance of this small amount of factor IX is unknown. However, it may be significant since only a few percent of normal IX levels are required to support haemostasis in the absence of trauma, and platelet factor IX could be released at sites of active coagulation.

  4. Does bipolar pacemaker current activate blood platelets?

    DEFF Research Database (Denmark)

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

    2009-01-01

    to the pacemaker can. METHODS: Platelet-rich plasma was prepared from two healthy subjects. Platelet reactivity to the agonist ADP was tested in paired samples in an aggregometer in a case/control setup. RESULTS: Eighteen of 46 tested pairs of platelet-rich plasma showed increased reactivity in the paced sample......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...

  5. 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.

  6. 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.

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

    African Journals Online (AJOL)

    Amira M. Elsayed

    2016-03-30

    Mar 30, 2016 ... patients with renal artery stenosis.10 Higher mean platelet vol- ume (MPV) values have been established ... connections between MPV with cerebrovascular accidents and their prognosis have already ... increased MPV in different subtypes of brain stroke, both in the acute phase and long after disease.17.

  8. Pathogen-Reduced, Platelet Additive Solution, Extended Stored Platelets (PREPS)

    Science.gov (United States)

    2015-10-01

    used for all future experiments. Platelet counts pre- and post-storage for up to 22 days confirmed the reproducibility of our original experiment...abdominal cramping . Slowing the collection rate, pausing the collection and/or administering oral calcium (TUMS) will effectively address these...muscle cramps , tremors, tetany, laryngospasm, seizures and life threatening cardiac arrhythmias. • Blood Loss: In rare and unusual circumstances, blood

  9. 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.

  10. Activation and extinction models for platelet adhesion.

    Science.gov (United States)

    David, T; Walker, P G

    2002-01-01

    Adherent platelets are an important part of both thrombus formation and in certain stages of atherogenesis. Platelets can be activated by potent chemicals released from adherent platelets and adhere far more readily than unactivated ones. An analytical and numerical model is presented utilising high Peclet number for the activation and adhesion of platelets in shear flows. The model uses a similarity transformation, which characterises the relationship between convective, diffusive transport and the bulk platelet activating reaction mechanism. A first order surface reaction mechanism is used to model platelet adhesion at the wall (cell) surface. The reduced Damköhler number, M, characterises the importance of the bulk reaction and includes both convective and diffusive terms. For a high rate of blood flow (M-->0) the activation of platelets can effectively be terminated. In contrast, for (M-->infinity) an inner layer of activated platelets exists with an infinitesimally thin reaction sheet separating activated and non-activated platelets. This characterisation by the Damköhler number highlights results found clinically, in that thrombus forms in areas of low shear (high M) and in some cases an increased blood flow (low M) can inhibit the activation of platelets completely. The model shows the critical balance that exists between convection, diffusion and reaction.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1989-05-01

    Using autologous /sup 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.

  12. 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

  13. Effect of Colchicine on Platelet-Platelet and Platelet-Leukocyte Interactions: a Pilot Study in Healthy Subjects.

    Science.gov (United States)

    Shah, Binita; Allen, Nicole; Harchandani, Bhisham; Pillinger, Michael; Katz, Stuart; Sedlis, Steven P; Echagarruga, Christina; Samuels, Svetlana Krasnokutsky; Morina, Pajazit; Singh, Prabhjot; Karotkin, Liza; Berger, Jeffrey S

    2016-02-01

    The cardioprotective mechanisms of colchicine in patients with stable ischemic heart disease remain uncertain. We tested varying concentrations of colchicine on platelet activity in vitro and a clinically relevant 1.8-mg oral loading dose administered over 1 h in 10 healthy subjects. Data are shown as median [interquartile range]. Colchicine addition in vitro decreased light transmission platelet aggregation only at supratherapeutic concentrations but decreased monocyte- (MPA) and neutrophil-platelet aggregation (NPA) at therapeutic concentrations. Administration of 1.8 mg colchicine to healthy subjects had no significant effect on light transmission platelet aggregation but decreased the extent of MPA (28 % [22-57] to 22 % [19-31], p = 0.05) and NPA (19 % [16-59] to 15 % [11-30], p = 0.01), platelet surface expression of PAC-1 (370 mean fluorescence intensity (MFI) [328-555] to 333 MFI [232-407], p = 0.02) and P-selectin (351 MFI [269-492] to 279 [226-364], p = 0.03), and platelet adhesion to collagen (10.2 % [2.5-32.6] to 2.0 % [0.2-9.5], p = 0.09) 2 h post-administration. Thus, in clinically relevant concentrations, colchicine decreases expression of surface markers of platelet activity and inhibits leukocyte-platelet aggregation but does not inhibit homotypic platelet aggregation.

  14. 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......, is associated with circulating activated platelets and platelet hyperreactivity to ADP, despite the confounding variable of more nephropathy patients receiving aspirin. This platelet activation is likely to contribute to the known increased risk of cardiovascular events in patients with diabetic nephropathy...... 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...

  15. 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.

  16. Platelet activation and platelet-leukocyte interaction in generalized aggressive periodontitis.

    Science.gov (United States)

    Zhan, Yalin; Lu, Ruifang; Meng, Huanxin; Wang, Xian'e; Hou, Jianxia

    2016-11-01

    Generalized aggressive periodontitis (GAgP) is an inflammatory disease of host response to bacterial challenge. To explore the role of platelets in host-microbial interactions in patients with periodontitis, 124 patients with GAgP and 57 healthy subjects were enrolled. Reliable indicators of subclinical platelet functional status, platelet count (PLT), platelet large cell ratio (PLCR), and mean platelet volume (MPV), were significantly lower in the GAgP group than in the control group and were negatively correlated with clinical periodontal parameters. The levels of important cytosolic protein in neutrophils, calprotectin (S100A8/A9) in plasma, and gingival crevicular fluid (GCF) were significantly higher in patients with GAgP compared with healthy subjects. Moreover, the GCF calprotectin level was negatively correlated with PLCR and MPV values. To explore the possible mechanisms of changes in platelet indices in periodontitis, flow cytometry analysis was performed, and patients with GAgP were found to have a higher status of platelet activation compared with healthy controls. Porphyromonas gingivalis (P. gingivalis) and recombinant human S100A8/A9 (rhS100A8/A9) induced platelet activation and facilitated platelet-leukocyte aggregate formation in whole blood of healthy subjects. In response to P. gingivalis and rhS100A8/A9, platelets from patients with GAgP increased activation and increased formation of platelet-leukocyte aggregates compared with those from healthy subjects. Platelet aggregates and platelets attached to leukocytes were found on gingival tissues from patients with GAgP, suggesting that decreased platelet size and count in the circulation might be related to consumption of large, activated platelets at inflamed gingiva. Platelets may have a previously unrecognized role in host response to periodontal infection. © Society for Leukocyte Biology.

  17. Pathogen Reduced, Plasmalyte Extended Stored Platelets

    Science.gov (United States)

    2017-10-01

    to 15 December 2017. The radiation safety approval was also renewed. In December 2016 annual reports were submitted to both the Food and Drug...research proposal, we are interested in evaluating metabolic, functional and viability changes to apheresis platelets preserved in an additive solution...Transfusion 1973;13, 61. 3. Murphy S, Gardner FH. Platelet preservation . Effect of storage temperature on maintenance of platelet viability – deleterious

  18. 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.

  19. The Platelet Function Defect of Cardiopulmonary Bypass.

    Science.gov (United States)

    1992-11-24

    Shattil SJ: Direct detection of activated platelets and platelet- derived microparticles in humans. Blood 75:128, 1990 19. van Oeveren W, Harder MP...standard curve from 0 to 70 nM from the purified glycocalicin samples. The plasma glycocalicin concentration of unknown plasma samples was derived ...either a) degranulated platelets that are very rapidly cleared from the circulation66 (possibly by circulating monocytes and neutrophils67-68), b) non

  20. 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...... to the lack of standardization of these tests for use in children. Areas covered: The present review summarizes developmental hemostasis with a focus on the differences in platelet adhesion, activation and aggregation, between preterm neonates, full-term neonates, during childhood and in adults. Some...

  1. Platelet transfusion for patients with cancer.

    Science.gov (United States)

    Fletcher, Craig H; DomBourian, Melkon G; Millward, Peter A

    2015-01-01

    Platelet transfusion is a critical and often necessary aspect of managing cancer. Low platelet counts frequently lead to bleeding complications; however, the drugs used to combat malignancy commonly lead to decreased production and destruction of the very cell whose function is essential to stop bleeding. The transfusion of allogeneic platelet products helps to promote hemostasis, but alloimmunization may make it difficult to manage other complications associated with cancer. The literature relating to platelet transfusion in patients with cancer was reviewed. Platelet storage, dosing, transfusion indications, and transfusion response are essential topics for health care professionals to understand because many patients with cancer will require platelet transfusions during the course of treatment. The workup and differentiation of non-immune-mediated compared with immune-mediated platelet refractoriness are vital because platelet management is different between types of refractoriness. A combination of appropriate utilization of platelet inventory and laboratory testing coupled with communication between those caring for patients with cancer and those providing blood products is essential for effective patient care.

  2. Human platelets attenuate Aspergillus species via granule-dependent mechanisms.

    NARCIS (Netherlands)

    Perkhofer, S.; Kehrel, B.E.; Dierich, M.P.; Donnelly, J.P.; Nussbaumer, W.; Hofmann, J.; Eiff, C. von; Lass-Florl, C.

    2008-01-01

    Using laser scanning microscopy, we investigated whether platelets are capable of internalizing Aspergillus conidia and examined Aspergillus-platelet adherence. The influence of platelets on fungal growth was evaluated by assessing galactomannan (GM) release, hyphal elongation, and colony size. A

  3. Psychosocial development of full term singletons, born after preimplantation genetic diagnosis (PGD) at preschool age and family functioning: a prospective case-controlled study and multi-informant approach.

    Science.gov (United States)

    Winter, C; Van Acker, F; Bonduelle, M; Desmyttere, S; Nekkebroeck, J

    2015-05-01

    Do full term singletons born after preimplantation genetic diagnosis (PGD) differ in their psychosocial functioning from children born after intracytoplasmic sperm injection (ICSI) and spontaneous conceived controls (SC)? The psychosocial maturation process of 5-6-year-old PGD children is comparable between the three conception groups (PGD, ICSI and SC). In general, a lot of research has been published regarding follow-up of children born after artificial reproductive technologies (ART), which mainly is reassuring. But the ART population itself is marked by broad diversity [IVF, ICSI, gamete donation, preimplantation genetic screening (PGS) or PGD] which complicates comparisons. Some literature concerning the socio-emotional development of PGD/PGS children is available and it suggests a normal maturation process. However, the complex reality of PGD families (e.g. safety of the technique and psychological burden of genetic histories) asks for an exclusive PGD sample with matched control groups and a multi-informant approach. Between April 2011 and May 2013, the psychosocial wellbeing of preschoolers and their families born after PGD was assessed in a prospective case-controlled, matched follow-up study, with a multi-informant approach. A group of 47 PGD, 50 ICSI and 55 SC 5-6-year-old children participated in a follow-up study performed at the Centre for Medical Genetics of the Universitair Ziekenhuis Brussel (UZ Brussel). Assessments took place in the hospital and in kindergartens. Children performed the Bene-Anthony family relations test (FRT), yielding their perceptions upon family relationships. Parents and teachers completed the child behaviour checklist (CBCL) and Caregiver Teacher Report Form (C-/TRF), respectively. Parental and family functioning were measured by the NEO-FFi, the parenting stress index (PSI), the Greenberger Work-Parenting Investment Questionnaire and the Marlowe-Crowne Social Desirability Scale (MCSDS). Statistical analysis was performed by

  4. 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.

  5. 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

  6. Cryopreservation of buffy-coat-derived platelet concentrates in dimethyl sulfoxide and platelet additive solution.

    Science.gov (United States)

    Johnson, L N; Winter, K M; Reid, S; Hartkopf-Theis, T; Marks, D C

    2011-04-01

    Platelets prepared in plasma can be frozen in 6% dimethyl sulfoxide (Me(2)SO) and stored for extended periods at -80°C. The aim of this study was to reduce the plasma present in the cryopreserved product, by substituting plasma with platelet additive solution (PAS; SSP+), whilst maintaining in vitro platelet quality. Buffy coat-derived pooled leukoreduced platelet concentrates were frozen in a mixture of SSP+, plasma and 6% Me(2)SO. The platelets were concentrated, to avoid post-thaw washing, and frozen at -80°C. The cryopreserved platelet units (n=9) were rapidly thawed at 37°C, reconstituted in 50% SSP+/plasma and stored at 22°C. Platelet recovery and quality were examined 1 and 24h post-thaw and compared to the pre-freeze samples. Upon thawing, platelet recovery ranged from 60% to 80%. However, there were differences between frozen and liquid-stored platelets, including a reduction in aggregation in response to ADP and collagen; increased CD62P expression; decreased viability; increased apoptosis and some loss of mitochondrial membrane integrity. Some recovery of these parameters was detected at 24h post-thaw, indicating an extended shelf-life may be possible. The data suggests that freezing platelets in 6% Me(2)SO and additive solution produces acceptable in vitro platelet quality. Copyright © 2011 Elsevier Inc. All rights reserved.

  7. Reduced platelet activation and platelet aggregation in patients with alcoholic liver cirrhosis

    DEFF Research Database (Denmark)

    Vinholt, Pernille Just; Hvas, Anne-Mette; Nielsen, Christian

    2018-01-01

    in stimulated samples were lower in patients versus healthy individuals, e.g., after collagen-related peptide stimulation, the median percentage of platelets positive for activated glycoprotein IIb/IIIa was 85% (IQR 70-94) in patients versus 97% (IQR 94-99) in healthy individuals, p 0.001; lower platelet...... adenosine diphosphate, thrombin receptor-activating peptide, arachidonic acid, collagen, and collagen-related peptide. Patients had lower median platelet count than healthy individuals, 125 × 10(9)/L (interquartile range [IQR] 90-185) versus 240 × 10(9) (IQR 204-285), p 0.001. Platelet activation levels...... activation capacity being associated with low platelet count and Child-Pugh class B/C cirrhosis. Flow cytometric platelet aggregation was reduced in patients for collagen-related peptide and for adenosine diphosphate, e.g., platelet aggregation (mean ± standard deviation) was 57% ± 4 in patients versus 70...

  8. Platelet Activation by Streptococcus pyogenes Leads to Entrapment in Platelet Aggregates, from Which Bacteria Subsequently Escape

    Science.gov (United States)

    Svensson, Lisbeth; Baumgarten, Maria; Mörgelin, Matthias

    2014-01-01

    Platelet activation and aggregation have been reported to occur in response to a number of Gram-positive pathogens. Here, we show that platelet aggregates induced by Streptococcus pyogenes were unstable and that viable bacteria escaped from the aggregates over time. This was not due to differential activation in response to the bacteria compared with physiological activators. All the bacterial isolates induced significant platelet activation, including integrin activation and alpha and dense-granule release, at levels equivalent to those induced by potent physiological platelet activators that induced stable aggregates. The ability to escape the aggregates and to resist the antibacterial effects of platelets was dependent on active protein synthesis by the bacteria within the aggregate. We conclude that S. pyogenes bacteria can temporarily cover themselves with activated platelets, and we propose that this may facilitate survival of the bacteria in the presence of platelets. PMID:25069984

  9. 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...

  10. 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

  11. 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

  12. The origin and function of platelet glycosyltransferases

    DEFF Research Database (Denmark)

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

    2012-01-01

    in release of soluble glycosyltransferase activities and that platelets contain sufficient levels of sugar nucleotides for detection of glycosylation of exogenously added substrates. Blood platelets are therefore a rich source of both glycosyltransferases and donor sugar substrates, which can be released...

  13. 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.

  14. 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

  15. NOD2 Receptor is Expressed in Platelets and Enhances Platelet Activation and Thrombosis

    Science.gov (United States)

    Zhang, Si; Zhang, Shenghui; Hu, Liang; Zhai, Lili; Xue, Ruyi; Ye, Jianqin; Chen, Leilei; Cheng, Guanjun; Mruk, Jozef; Kunapuli, Satya P.; Ding, Zhongren

    2015-01-01

    Background Pattern recognition receptor NOD2 (nucleotide binding oligomerization domain 2) is well investigated in immunity, its expression and function in platelets has never been explored. Method and Results Using RT-PCR and Western blot we show that both human and mouse platelets express NOD2, and its agonist MDP induced NOD2 activation as evidenced by receptor dimerization. NOD2 activation potentiates platelet aggregation and secretion induced by low concentration of thrombin or collagen, as well as clot retraction. These potentiating effects of MDP were not seen in platelets from NOD2-deficient mice. Plasma from septic patients also potentiates platelet aggregation induced by thrombin or collagen NOD2-dependently. Using intravital microscopy, we found that MDP administration accelerated in vivo thrombosis in FeCl3-injured mesenteric arteriole thrombosis mouse model. Platelet depletion and transfusion experiments confirmed that NOD2 from platelets contributes to the in vivo thrombosis in mice. NOD2 activation also accelerates platelet-dependent hemostasis. We further found that platelets express RIP2 (receptor-interacting protein 2), and provided evidences suggesting that MAPK and NO/sGC/cGMP/PGK pathways downstream of RIP2 mediate the role of NOD2 in platelets. Finally, MDP stimulates proinflammatory cytokine IL-1β maturation and accumulation in human and mouse platelets NOD2-dependently. Conclusions NOD2 is expressed in platelets and functions in platelet activation and arterial thrombosis, possibly during infection. To our knowledge, this is the first study on NOD-like receptors in platelets which links thrombotic events to inflammation. PMID:25825396

  16. 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.

  17. 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.

  18. Modulatory effect of coffee on platelet function.

    Science.gov (United States)

    Bhaskar, Shobha; Rauf, Arun A

    2010-01-01

    Blood platelets play a major role in cardiovascular disease (CVD) and thrombosis. Conflicting information exists regarding the effect of coffee consumption on the cardiovascular system. We have investigated whether the consumption of moderate amount of coffee affect platelet functions and primary hemostasis in vivo in normal and high fat diet fed rats. Coffee fed group showed significant (P coffee treated group. Platelet aggregation studies with ADP, collagen, arachidonic acid and epinephrine showed significant (P coffee fed group. Scanning electron microscopic studies revealed that platelet aggregation tendency increased in HFD group and was reduced in coffee fed group. These results indicate that coffee is active in inhibiting platelet aggregation, a critical step involved in thrombosis.

  19. Application of an optimized flow cytometry-based quantification of Platelet Activation (PACT: Monitoring platelet activation in platelet concentrates.

    Directory of Open Access Journals (Sweden)

    Cécile H Kicken

    Full Text Available Previous studies have shown that flow cytometry is a reliable test to quantify platelet function in stored platelet concentrates (PC. It is thought that flow cytometry is laborious and hence expensive. We have optimized the flow cytometry-based quantification of agonist induced platelet activation (PACT to a labor, time and more cost-efficient test. Currently the quality of PCs is only monitored by visual inspection, because available assays are unreliable or too laborious for use in a clinical transfusion laboratory. Therefore, the PACT was applied to monitor PC activation during storage.The optimized PACT was used to monitor 5 PCs during 10 days of storage. In brief, optimized PACT uses a ready-to-use reaction mix, which is stable at -20°C. When needed, a test strip is thawed and platelet activation is initiated by mixing PC with PACT. PACT was based on the following agonists: adenosine diphosphate (ADP, collagen-related peptide (CRP and thrombin receptor-activating peptide (TRAP-6. Platelet activation was measured as P-selectin expression. Light transmission aggregometry (LTA was performed as a reference.Both PACT and LTA showed platelet function decline during 10-day storage after stimulation with ADP and collagen/CRP; furthermore, PACT showed decreasing TRAP-induced activation. Major differences between the two tests are that PACT is able to measure the status of platelets in the absence of agonists, and it can differentiate between the number of activated platelets and the amount of activation, whereas LTA only measures aggregation in response to an agonist. Also, PACT is more time-efficient compared to LTA and allows high-throughput analysis.PACT is an optimized platelet function test that can be used to monitor the activation of PCs. PACT has the same accuracy as LTA with regard to monitoring PCs, but it is superior to both LTA and conventional flow cytometry based tests with regard to labor-, time- and cost efficiency.

  20. 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

  1. 21 CFR 864.5700 - Automated platelet aggregation system.

    Science.gov (United States)

    2010-04-01

    ... addition of an aggregating reagent to a platelet-rich plasma. (b) Classification. Class II (performance... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Automated platelet aggregation system. 864.5700... § 864.5700 Automated platelet aggregation system. (a) Identification. An automated platelet aggregation...

  2. 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…

  3. 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.

  4. Platelet function in patients with meningococcal meningitis at the ...

    African Journals Online (AJOL)

    The following platelet functions tests were performed; platelet counts, platelet adhesiveness, platelet aggregation and clot retraction. Results: Fifty seven patients (41 males and 16 females) with meningococcal meningitis were studied. Their mean age was 25.5 ± 8.32 years with a range of 15 to 45 years. Five patients had ...

  5. Discovery-based strategies for studying platelet function.

    Science.gov (United States)

    Flaumenhaft, R; Dilks, J R

    2008-04-01

    The platelet is an anucleate cell, complicating efforts to study platelet function by traditional genetic means. Discovery-based strategies have lead to the identification of pharmacological agents capable of targeting specific proteins critical for platelet activation. This review will address the evolution of discovery-based strategies to identify probes that are at once useful reagents for studying platelet activation and effective therapeutics.

  6. Assessment of platelet profile of healthy volunteers in the trimesters ...

    African Journals Online (AJOL)

    Assessment of platelet profile of healthy volunteers in the trimesters of pregnancy in Benin City, Nigeria. ... Thus PDW compensates for these reductions and a lack of this compensatory increase may aggravate the effect of thrombocytopenia in pregnancy. Platelet Count, Plateletcrit, Mean Platelet Volume, Platelet ...

  7. 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.

  8. 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

  9. 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.

  10. 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

  11. Platelet antibody: review of detection methods

    Energy Technology Data Exchange (ETDEWEB)

    Schwartz, K.A.

    1988-10-01

    The driving force behind development of in vitro methods for platelet antibodies is identification of plasma factors causing platelet destruction. Early methods relied on measurement of platelet activation. Current methods are more specific and use a purified antibody against immunoglobulin or complement, which is usually labeled with /sup 125/I or tagged with an enzyme or fluorescein. Comparisons of quantitation of platelet-associated IgG show wide variability between different methods. The disparate results can be related both to differences in binding of secondary antibodies to immunoglobulin in solution compared to immunoglobulins attached to platelets and to the improper assumption that the binding ratio between the secondary detecting and primary antiplatelet antibody is one. Most assays can 1) identify neonatal isoimmune thrombocytopenia and posttransfusion purpura, 2) help to differentiate between immune and nonimmune thrombocytopenias, 3) help to sort out the offending drug when drug-induced thrombocytopenia is suspected, and 4) identify platelet alloantibodies and potential platelet donors via a cross match assay for refractory patients. However, the advantages of quantitative assays over qualitative methods with respect to predictions of patients clinical course and response to different treatments remain to be investigated. 61 references.

  12. Aspirin treatment reduces platelet resistance to deformation.

    Science.gov (United States)

    Burris, S M; Smith, C M; Rao, G H; White, J G

    1987-01-01

    The present investigation has evaluated the influence of aspirin, its constituents, and other nonsteroidal anti-inflammatory agents on the resistance of human platelets to aspiration into micropipettes. Aspirin increased the length of platelet extensions into the micropipette over the entire negative tension range of 0.04 to 0.40 dynes/cm after exposure to the drug in vitro or after ingestion of the agent. Other cyclooxygenase inhibitors, ibuprofen and indomethacin, did not increase platelet deformability. The influence of aspirin was mimicked to some degree by high concentrations of salicylic acid, but acetylation of platelets with acetic anhydride had little influence on platelet deformability. Incubation of platelets with both salicylic acid and acetic anhydride had no more effect than salicylic acid alone. Benzoic acid, chemically similar to salicylic acid, had a minimal effect. The studies demonstrate that aspirin makes platelets more deformable, while components of the drug or other nonsteroidal antiinflammatory agents and cyclooxygenase inhibitors do not have the same influence on resistance to deformation.

  13. Platelet production from induced pluripotent stem cells.

    Science.gov (United States)

    Sugimoto, N; Eto, K

    2017-09-01

    Ex vivo production of human platelets has been pursued as an alternative measure to resolve limitations in the supply and safety of current platelet transfusion products. To this end, induced pluripotent stem cells (iPSCs) are considered an ideal global source, as they are not only pluripotent and self-renewing, but are also available from basically any person, have relatively few ethical issues, and are easy to manipulate. From human iPSCs, megakaryocyte (MK) lines with robust proliferation capacity have been established by the introduction of specified sets of genes. These expandable MKs are also cryopreservable and thus would be suitable as master cells for good manufacturing practice (GMP)-grade production of platelets, assuring availability on demand and safety against blood-borne infections. Meanwhile, developments in bioreactors that physically mimic the in vivo environment and discovery of substances that promote thrombopoiesis have yielded competent platelets with improved efficiency. The derivation of platelets from iPSCs could further resolve transfusion-related alloimmune complications through the manufacturing of autologous products and human leukocyte antigen (HLA)-compatible platelets from stocked homologous HLA-type iPSC libraries or by manipulation of HLAs and human platelet antigens (HPAs). Considering these key advances in the field, HLA-deleted platelets could become a universal product that is manufactured at industrial level to safely fulfill almost all demands. In this review, we provide an overview of the ex vivo production of iPSC-derived platelets toward clinical applications, a production that would revolutionize the blood transfusion system and lead the field of iPSC-based regenerative medicine. © 2017 International Society on Thrombosis and Haemostasis.

  14. Analysis of aggregation of platelets in thrombosis

    Science.gov (United States)

    Ahuja, Suresh

    Platelets are key players in thrombus formation by first rolling over collagen bound von Willebrand factor followed by formation of a stable interaction with collagen. The first adhered platelets bind additional platelets until the whole injury is sealed off by a platelet aggregate. The coagulation system stabilizes the formed platelet plug by creating a tight fibrin network, and then wound contraction takes place because of morphological changes in platelets. Coagulation takes place by platelet activation and aggregation mainly through fibrinogen polymerization into fibrin fibers. The process includes multiple factors, such as thrombin, plasmin, and local shear-rate which regulate and control the process. Coagulation can be divided into two pathways: the intrinsic pathway and the extrinsic pathway. The intrinsic pathway is initiated by the exposure of a negatively charged. It is able to activate factor XII, using a complex reaction that includes prekallikrein and high-molecular-weight kininogen as cofactors.. Thrombin is the final enzyme that is needed to convert fibrinogen into fibrin. The extrinsic pathway starts with the exposure of tissue factor to the circulating blood, which is the major initiator of coagulation. There are several feedback loops that reinforce the coagulation cascade, resulting in large amounts of thrombin. It is dependent on the presence of pro-coagulant surfaces of cells expressing negatively charged phospholipids--which include phosphatidylserine (PS)--on their outer membrane. PS-bearing surfaces are able to increase the efficiency of the reactions by concentrating and co-localizing coagulation factors.. Aggregation of platelets are analyzed and compared to adhesion of platelet to erythrocyte and to endothelial cells. This abstract is replacing MAR16-2015-020003.

  15. 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

  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. Platelet Function Analyzed by Light Transmission Aggregometry

    DEFF Research Database (Denmark)

    Hvas, Anne-Mette; Favaloro, Emmanuel J

    2017-01-01

    Analysis of platelet function is widely used for diagnostic work-up in patients with increased bleeding tendency. During the last decades, platelet function testing has also been introduced for evaluation of antiplatelet therapy, but this is still recommended for research purposes only. Platelet...... 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...

  20. Thrombosis and platelets: an update.

    Science.gov (United States)

    Koupenova, Milka; Kehrel, Beate E; Corkrey, Heather A; Freedman, Jane E

    2017-03-14

    Haemostasis and thrombosis are complex, multifactorial processes. There is an evolving understanding of the mechanisms influencing vascular occlusion and the role of inflammation and immunity. Despite major advances in elucidating the mechanistic pathways mediating platelet function and thrombosis, challenges in the treatment of vascular occlusive diseases persist. Pharmacological advances have greatly affected thrombotic outcomes, but this has led to the unwanted side effect of bleeding. Detailed assessment of the impact of non-thrombotic diseases on haemostasis and thrombosis is necessary to better evaluate thrombotic risk and establish optimal treatment. This review will focus on recent advances in understanding the contribution of evolving risk factors to thrombosis. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2016. For Permissions, please email: journals.permissions@oup.com.

  1. 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.

  2. 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

  3. Platelet pathophysiology, pharmacology, and function in coronary artery disease.

    Science.gov (United States)

    Ibrahim, Homam; Kleiman, Neal S

    2017-11-01

    Platelets play a key role in the pathophysiology of coronary artery disease and acute coronary syndromes. Our understanding of platelet function in thrombus formation has increased considerably, resulting in the development of clinically effective treatment strategies and identification of new targets. An underappreciated platelet function is their contribution toward acute and chronic inflammatory processes including atherogenesis. In this review, we discuss the role of platelets in atherosclerosis and thrombosis, platelet function testing, and the pharmacology of currently available antiplatelet drugs.

  4. 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.

  5. 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.

  6. 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...

  7. Functional recovery of stored platelets after transfusion

    NARCIS (Netherlands)

    Bikker, Angela; Bouman, Esther; Sebastian, Silvie; Korporaal, Suzanne J A; Urbanus, Rolf T; Fijnheer, Rob; Boven, Leonie A; Roest, Mark

    BACKGROUND: Platelet (PLT) concentrates are prophylactically given to prevent major bleeding complications. The corrected count increment (CCI) is currently the only tool to monitor PLT transfusion efficacy. PLT function tests cannot be performed in patients with thrombocytopenia. Therefore, an

  8. 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.

  9. 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.

  10. 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.

  11. Platelet-Derived Serotonin Mediates Liver Regeneration

    Science.gov (United States)

    Lesurtel, Mickael; Graf, Rolf; Aleil, Boris; Walther, Diego J.; Tian, Yinghua; Jochum, Wolfram; Gachet, Christian; Bader, Michael; Clavien, Pierre-Alain

    2006-04-01

    The liver can regenerate its volume after major tissue loss. In a mouse model of liver regeneration, thrombocytopenia, or impaired platelet activity resulted in the failure to initiate cellular proliferation in the liver. Platelets are major carriers of serotonin in the blood. In thrombocytopenic mice, a serotonin agonist reconstituted liver proliferation. The expression of 5-HT2A and 2B subtype serotonin receptors in the liver increased after hepatectomy. Antagonists of 5-HT2A and 2B receptors inhibited liver regeneration. Liver regeneration was also blunted in mice lacking tryptophan hydroxylase 1, which is the rate-limiting enzyme for the synthesis of peripheral serotonin. This failure of regeneration was rescued by reloading serotonin-free platelets with a serotonin precursor molecule. These results suggest that platelet-derived serotonin is involved in the initiation of liver regeneration.

  12. 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

  13. 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.

  14. Platelet Glycoprotein Ib-IX and Malignancy

    Science.gov (United States)

    2010-09-01

    whether adjunct anti-GP Ib-IX therapy could benefit the breast cancer patient with malignant disease. Body Below we list the 3 Specific Aims from our...Platelet Glycoprotein Ib-IX and Malignancy PRINCIPAL INVESTIGATOR: Jerry Ware, Ph.D...AND SUBTITLE Platelet Glycoprotein Ib-IX and Malignancy 5a. CONTRACT NUMBER 5b. GRANT NUMBER W81XWH-08-1-0576 5c

  15. 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

  16. 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.

  17. Pathogen-Reduced, Extended Platelet Storage in Platelet Additive Solution (PAS)

    Science.gov (United States)

    2016-10-01

    transfusion. Our project proposes to determine the efficacy of using a pathogen inactivation technique (Mirasol) coupled with a platelet additive solution...apheresis platelet collection and drawing blood samples. • Subjects of child-bearing potential (either male or female) must agree to use an effective

  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

    Platelet activation at sites of vascular injury is crucial for hemostasis, but it may also cause myocardial infarction or stroke. Cytoskeletal reorganization is essential for platelet activation and secretion. The small GTPase Cdc42 has been implicated as an important mediator of filopodia...

  19. 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

  20. 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.

  1. Microtubule and cortical forces determine platelet size during vascular platelet production.

    Science.gov (United States)

    Thon, Jonathan N; Macleod, Hannah; Begonja, Antonija Jurak; Zhu, Jie; Lee, Kun-Chun; Mogilner, Alex; Hartwig, John H; Italiano, Joseph E

    2012-05-22

    Megakaryocytes release large preplatelet intermediates into the sinusoidal blood vessels. Preplatelets convert into barbell-shaped proplatelets in vitro to undergo repeated abscissions that yield circulating platelets. These observations predict the presence of circular-preplatelets and barbell-proplatelets in blood, and two fundamental questions in platelet biology are what are the forces that determine barbell-proplatelet formation, and how is the final platelet size established. Here we provide insights into the terminal mechanisms of platelet production. We quantify circular-preplatelets and barbell-proplatelets in human blood in high-resolution fluorescence images, using a laser scanning cytometry assay. We demonstrate that force constraints resulting from cortical microtubule band diameter and thickness determine barbell-proplatelet formation. Finally, we provide a mathematical model for the preplatelet to barbell conversion. We conclude that platelet size is limited by microtubule bundling, elastic bending, and actin-myosin-spectrin cortex forces.

  2. Flow cytometry analysis of platelet populations: usefulness for monitoringthe storage lesion in pooled buffy-coat platelet concentrates.

    Science.gov (United States)

    Vučetić, Dušan; Ilić, Vesna; Vojvodić, Danilo; Subota, Vesna; Todorović, Milena; Balint, Bela

    2018-01-01

    Early detection of the platelet storage lesion is still a challenge in transfusion practice. Using flow cytometry, we evaluated the appearance of the storage lesion, based on the expression of platelet activation markers, in total platelets and platelet populations. Buffy-coat-derived platelet concentrates were stored under standard conditions for 5 days. The expression of activation antigens CD42b, CD36, CD62p and phosphatidylserine on total platelets and populations of small, medium-sized and large platelets was analysed by flow cytometry on storage days 1, 3 and 5. The activation/lesion on total platelets and each platelet population was detected on storage day 3, by the increased expression of CD36. On the same day, increased expression of CD42b and CD62p was detected, but only on large platelets. Small and medium-sized platelets had increased CD62p expression only on day 5. Externalisation of phosphatidylserine was not detected. Evaluation of the level of expression of various activation markers on different platelet populations could be an additional valid analysis in cell quality control of platelet concentrates, and in the assessment of novel approaches to platelet concentrate manipulation.

  3. A General Aspect of Platelet Rich Plasma

    Directory of Open Access Journals (Sweden)

    Onur ORAL

    2015-08-01

    Full Text Available The aim of this scientific paper is to introduce Platelet Rich Plasma (PRP cure method by people who never heard about it. People can hurt their selves, thus they can have damaged tissue; for instance broken bone, a scar or a wounded area. Furthe rmore damaged tissue can be a cartilage tissue, which takes very long time to heal. Platelets, those exist in the veins as thrombus, come up to repair those damaged tissues. However, platelets would be insufficient to cure damaged area in a short time. At this point PRP cure method give a hand to the healing process. By centrifuging people’s own blood via special kits, platelets can be separated from blood cells as plasma. That plasma’s platelet density is 3 - 5 times greater than that blood’s platelet densit y. Afterwards PRP method is implemented by injection of plasma to the damaged area or tissue. After implementation of 2 - 4 sessions per week, damaged tissue can be regenerated. It is fast healing method because densified platelet plasma is used; and it is s afe because that plasma is obtained from people’s own blood. PRP can be implemented on many areas; for instance on dentistry, sports medicine, different kind of surgeries such as plastic, vascular or orthopedic and so on. When soccer players brake their le gs, their sports life come to the end, but what if their broken legs was healed better and faster than general healing process? To sum up, PRP is very safe and the future of healing process.

  4. 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

  5. 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 

  6. Lea blood group antigen on human platelets

    Energy Technology Data Exchange (ETDEWEB)

    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 /sup 125/I. Human IgG anti-Lea antibody was used either in a two stage radioassay with /sup 125/I-labeled mouse monoclonal IgG anti-human IgG as the second antibody or, alternatively, purified by Staph protein A chromatography, labeled with /sup 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.

  7. 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.)

  8. 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.

  9. Functional platelet defects in children with severe chronic ITP as tested with 2 novel assays applicable for low platelet counts.

    Science.gov (United States)

    van Bladel, Esther R; Laarhoven, Annemieke G; van der Heijden, Laila B; Heitink-Pollé, Katja M; Porcelijn, Leendert; van der Schoot, C Ellen; de Haas, Masja; Roest, Mark; Vidarsson, Gestur; de Groot, Philip G; Bruin, Marrie C A

    2014-03-06

    Immune thrombocytopenia (ITP) is an autoimmune disease with a complex heterogeneous pathogenesis and a bleeding phenotype that is not necessarily correlated to platelet count. In this study, the platelet function was assessed in a well-defined cohort of 33 pediatric chronic ITP patients. Because regular platelet function test cannot be performed in patients with low platelet counts, 2 new assays were developed to determine platelet function: first, the microaggregation test, measuring in platelets isolated from 10 mL of whole blood the platelet potential to form microaggregates in response to an agonist; second, the platelet reactivity assay, measuring platelet reactivity to adenosine diphosphate (ADP), convulxin (CVX), and thrombin receptor activator peptide in only 150 μL of unprocessed whole blood. Patients with a severe bleeding phenotype demonstrated a decreased aggregation potential upon phorbol myristate acetate stimulation, decreased platelet degranulation following ADP stimulation, and a higher concentration of ADP and CVX needed to activate the glycoprotein IIbIIIa complex compared with patients with a mild bleeding phenotype. In conclusion, here we have established 2 functional tests that allow for evaluation of platelet function in patients with extremely low platelet counts (<10(9)). These tests show that platelet function is related to bleeding phenotype in chronic ITP.

  10. 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.

  11. 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

  12. Platelet serotonin content and transpulmonary platelet serotonin gradient in patients with pulmonary hypertension.

    Science.gov (United States)

    Ulrich, Silvia; Huber, Lars C; Fischler, Manuel; Treder, Ursula; Maggiorini, Marco; Eberli, Franz Robert; Speich, Rudolf

    2011-01-01

    The serotonin system has repeatedly been associated with the pathogenesis of pulmonary hypertension (PH). To comparatively analyze plasmatic and intrathrombocytic serotonin levels in arterial and mixed venous blood of patients with PH and unaffected controls to elucidate pulmonary serotonin metabolisms. Catheters were placed in the radial and pulmonary artery in patients with PH (n = 13) for diagnosis and in age-matched controls (n = 6) undergoing percutaneous closure of the patent foramen ovale. Arterial and mixed venous blood samples were immediately centrifuged to obtain plasma and platelets and thereafter frozen at -20°C. After careful thawing, plasmatic and platelet serotonin levels were determined by ELISA. PH was classified as arterial in 4 and chronic thromboembolic in 9 patients with a mean pulmonary artery pressure of 37 (interquartile range: 32-43) mm Hg. Platelet serotonin content was significantly lower in the PH patients than in the controls. The mean transpulmonary gradient (arterial-mixed venous) was negative in the PH group and positive in the controls. An inverse correlation was found between the arterial blood platelet serotonin content and pulmonary hemodynamics. Plasmatic serotonin levels did not differ between the PH and control groups. The lower platelet serotonin concentration in PH patients compared with unaffected controls is an unprecedented finding. The negative transpulmonary platelet serotonin gradient and the strong negative correlation of arterial blood platelet serotonin with pulmonary hemodynamics might indicate increased serotonin uptake in the lungs of PH patients. Copyright © 2010 S. Karger AG, Basel.

  13. 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.

  14. Platelet function investigation by flow cytometry

    DEFF Research Database (Denmark)

    Pedersen, Oliver Heidmann; Nissen, Peter H; Hvas, Anne-Mette

    2017-01-01

    Flow cytometry is an increasingly used method for platelet function analysis because it has some important advantages compared with other platelet function tests. Flow cytometric platelet function analyses only require a small sample volume (3.5 mL); however, to expand the field of applications, e...... assays. To examine the influence of sample volume, blood was collected from 20 healthy individuals in 1.0 mL, 1.8 mL, and 3.5 mL tubes. To examine the influence of the needle size on pre-activation, blood was drawn from another 13 healthy individuals with both a 19- and 21-gauge needle. For the reference...

  15. A snake venom metalloproteinase, kistomin, cleaves platelet glycoprotein VI and impairs platelet functions.

    Science.gov (United States)

    Hsu, C C; Wu, W B; Huang, T F

    2008-09-01

    Injuries to the vessel wall and subsequent exposure of the matrix of the subendothelial layer resulted in thrombus formation. Platelet glycoprotein (GP) Ib and VI play a crucial role in matrix-induced activation and aggregation of platelets. In the present study, we reported that the GPIb-cleaving snake venom metalloproteinase (SVMP), kistomin, inhibited collagen-induced platelet aggregation. Moreover, kistomin inhibited platelet aggregation induced by convulxin (CVX, a GPVI agonist) and a GPVI-specific antibody in a concentration and time-dependent manner. Kistomin treatment decreased platelet GPVI but not integrin alpha2beta1 and alphaIIbbeta3, accompanied with the formation of GPVI cleavage fragments, as determined by flow cytometric and Western blot analyses. In addition, intact platelet GPVI and recombinant GPVI were digested by kistomin to release 25- and 35-kDa fragments, suggesting that kistomin cleaved GPVI near the mucin-like region. We designed four synthetic peptides ranging from Leu180 to Asn249 as the substrates for kistomin and found that kistomin cleaved these synthetic peptides at FSE205/A206TA and NKV218/F219TT, as analyzed by MALDI-TOF-MS. In addition, GPVI-specific antibody-induced tyrosine kinase phosphorylation in platelets was reduced after kistomin pretreatment, and platelet adhesion to collagen but not to fibrinogen was attenuated by kistomin. We provided here the first evidence that a P-I snake venom metalloproteinase, kistomin, inhibits the interaction between collagen and platelet GPVI through its proteolytic activity on GPVI, thus providing an alternative strategy for developing new anti-thrombotic agents.

  16. 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.

  17. Activity of platelet hemostasis in children with spinal deformities.

    Science.gov (United States)

    Medvedev, I N; Lapshina, E V; Zavalishina, S Yu

    2010-10-01

    An increase of adhesion and aggregation functions of platelets in vivo and in vitro was detected in 5-6-year-old children with scoliosis. These disorders were caused by hyperproduction of von Willebrand's factor in the vascular wall and intensification of thromboxane production in blood platelets. Activation of thromboxane formation is the main cause of platelet hyperactivity in children with scoliosis. Correction of platelet hemostasis may include pathogenetically substantiated complex of therapeutic exercises, swimming, and massage.

  18. 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)

  19. 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.)

  20. 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

  1. 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.

  2. 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

  3. 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)

  4. Morphological and Functional Platelet Abnormalities in Berkeley Sickle Cell Mice

    Science.gov (United States)

    Shet, Arun S.; Hoffmann, Thomas J.; Jirouskova, Marketa; Janczak, Christin A.; Stevens, Jacqueline R.M.; Adamson, Adewole; Mohandas, Narla; Manci, Elizabeth A.; Cynober, Therese; Coller, Barry S.

    2009-01-01

    Berkeley sickle cell mice are used as an animal model of human sickle cell disease but there are no reports of platelet studies in this model. Since humans with sickle cell disease have platelet abnormalities, we studied platelet morphology and function in Berkeley mice (SS). We observed elevated mean platelet forward angle light scatter (FSC) values (an indirect measure of platelet volume) in SS compared to wild type (WT) (37 ± 3.2 vs. 27 ± 1.4, mean ± SD; p Howell-Jolly bodies and “pocked” erythrocytes (p <0.001 for both) suggesting splenic dysfunction. SS mice also had elevated numbers of thiazole orange positive platelets (5 ± 1 % vs. 1 ± 1%; p <0.001), normal to low plasma thrombopoietin levels, normal plasma glycocalicin levels, normal levels of platelet recovery, and near normal platelet life spans. Platelets from SS mice bound more fibrinogen and antibody to P-selectin following activation with a threshold concentration of a protease activated receptor (PAR)-4 peptide compared to WT mice. Enlarged platelets are associated with a predisposition to arterial thrombosis in humans and some humans with SCD have been reported to have large platelets. Thus, additional studies are needed to assess whether large platelets contribute either to pulmonary hypertension or the large vessel arterial occlusion that produces stroke in some children with sickle cell disease. PMID:18374611

  5. L-carnitine modulates blood platelet oxidative stress.

    Science.gov (United States)

    Saluk-Juszczak, Joanna; Olas, Beata; Wachowicz, Barbara; Glowacki, Rafal; Bald, Edward

    2010-08-01

    The oxidative stress induced by acute exertion may interfere with blood platelet activation. The beneficial effect of L-carnitine (gamma-trimethylamino-beta-hydroxybutyric acid) on oxidative stress in blood platelets has not been fully investigated; however, different studies indicate that this compound modulates platelet functions. The aim of our study was to assess the effects of L-carnitine on platelet activation and oxidative/nitrative protein damage (determined by the levels of protein carbonyl groups, thiol groups, and 3-nitrotyrosine residues) in resting blood platelets or platelets treated with peroxynitrite (ONOO(-), a strong physiological oxidant) in vitro. We also investigated the effects of L-carnitine on the level of platelet glutathione and on the formation of superoxide anion radicals O2(-*), lipid peroxidation measured by thiobarbituric acid reactive substances (TBARS) in blood platelets stimulated by thrombin (a strong physiological agonist), and platelet aggregation induced by adenosine diphosphate (a strong physiological stimulator). We have observed that carnitine decreases platelet activation (measured by platelet aggregation, the generation of O2(-*), and TBARS production). Moreover, our results in vitro demonstrate that carnitine may protect against oxidation of thiol groups induced by ONOO(-). Thus, carnitine may have some protectory effects against oxidative changes induced in blood platelets.

  6. 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 ...

  7. 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.

  8. Tocotrienols-induced inhibition of platelet thrombus formation and platelet aggregation in stenosed canine coronary arteries

    Directory of Open Access Journals (Sweden)

    Papasian Christopher J

    2011-04-01

    Full Text Available Abstract Background Dietary supplementation with tocotrienols has been shown to decrease the risk of coronary artery disease. Tocotrienols are plant-derived forms of vitamin E, which have potent anti-inflammatory, antioxidant, anticancer, hypocholesterolemic, and neuroprotective properties. Our objective in this study was to determine the extent to which tocotrienols inhibit platelet aggregation and reduce coronary thrombosis, a major risk factor for stroke in humans. The present study was carried out to determine the comparative effects of α-tocopherol, α-tocotrienol, or tocotrienol rich fraction (TRF; a mixture of α- + γ- + δ-tocotrienols on in vivo platelet thrombosis and ex vivo platelet aggregation (PA after intravenous injection in anesthetized dogs, by using a mechanically stenosed circumflex coronary artery model (Folts' cyclic flow model. Results Collagen-induced platelet aggregation (PA in platelet rich plasma (PRP was decreased markedly after treatment with α-tocotrienol (59%; P P P P P Next, pharmacokinetic studies were carried out and tocol levels in canine plasma and platelets were measured. As expected, α-Tocopherol treatment increased levels of total tocopherols in post- vs pre-treatment specimens (57 vs 18 μg/mL in plasma, and 42 vs 10 μg/mL in platelets. However, treatment with α-tocopherol resulted in slightly decreased levels of tocotrienols in post- vs pre-treatment samples (1.4 vs 2.9 μg/mL in plasma and 2.3 vs 2.8 μg/mL in platelets. α-Tocotrienol treatment increased levels of both tocopherols and tocotrienols in post- vs pre-treatment samples (tocopherols, 45 vs 10 μg/mL in plasma and 28 vs 5 μg/mL in platelets; tocotrienols, 2.8 vs 0.9 μg/mL in plasma and 1.28 vs 1.02 μg/mL in platelets. Treatment with tocotrienols (TRF also increased levels of tocopherols and tocotrienols in post- vs pre-treatment samples (tocopherols, 68 vs 20 μg/mL in plasma and 31.4 vs 7.9 μg/mL in platelets; tocotrienols, 8.6 vs 1

  9. Intravenous thrombolysis and platelet count.

    Science.gov (United States)

    Gensicke, Henrik; Al Sultan, Abdulaziz S; Strbian, Daniel; Hametner, Christian; Zinkstok, Sanne M; Moulin, Solène; Bill, Olivier; Zini, Andrea; Padjen, Visnja; Kägi, Georg; Pezzini, Alessandro; Seiffge, David J; Traenka, Christopher; Räty, Silja; Amiri, Hemasse; Zonneveld, Thomas P; Lachenmeier, Romina; Polymeris, Alexandros; Roos, Yvo B; Gumbinger, Christoph; Jovanovic, Dejana R; Curtze, Sami; Sibolt, Gerli; Vandelli, Laura; Ringleb, Peter A; Leys, Didier; Cordonnier, Charlotte; Michel, Patrik; Lyrer, Philippe A; Peters, Nils; Tatlisumak, Turgut; Nederkoorn, Paul J; Engelter, Stefan T

    2018-02-20

    To study the effect of platelet count (PC) on bleeding risk and outcome in stroke patients treated with IV thrombolysis (IVT) and to explore whether withholding IVT in PC 450 × 10 9 /L), and normal PC (150-450 × 10 9 /L [reference group]). Moreover, PC < 100 × 10 9 /L was compared to PC ≥ 100 × 10 9 /L. Unadjusted and adjusted odds ratios (ORs) with 95% confidence intervals (CIs) from the logistic regression models were calculated. Among 7,533 IVT-treated stroke patients, 6,830 (90.7%) had normal PC, 595 (7.9%) had thrombocytopenia, and 108 (1.4%) had thrombocytosis. Decreasing PC (every 10 × 10 9 /L) was associated with increasing risk of sICH (OR adjusted 1.03, 95% CI 1.02-1.05) but decreasing risk of poor outcome (OR adjusted 0.99, 95% CI 0.98-0.99) and mortality (OR adjusted 0.98, 95% CI 0.98-0.99). The risk of sICH was higher in patients with thrombocytopenic than in patients with normal PC (OR adjusted 1.73, 95% CI 1.24-2.43). However, the risk of poor outcome (OR adjusted 0.89, 95% CI 0.39-1.97) and mortality (OR adjusted 1.09, 95% CI 0.83-1.44) did not differ significantly. Thrombocytosis was associated with mortality (OR adjusted 2.02, 95% CI 1.21-3.37). Forty-four (0.3%) patients had PC < 100 × 10 9 /L. Their risks of sICH (OR unadjusted 1.56, 95% CI 0.48-5.07), poor outcome (OR adjusted 1.63, 95% CI 0.82-3.24), and mortality (OR adjusted 1.38, 95% CI 0.64-2.98) did not differ significantly from those of patients with PC ≥ 100 × 10 9 /L. Lower PC was associated with increased risk of sICH, while higher PC indicated increased mortality. Our data suggest that PC modifies outcome and complications in individual patients, while withholding IVT in all patients with PC < 100 × 10 9 /L is challenged. © 2018 American Academy of Neurology.

  10. Platelet turnover and kinetics in immune thrombocytopenic purpura: results with autologous 111In-labeled platelets and homologous 51Cr-labeled platelets differ

    Energy Technology Data Exchange (ETDEWEB)

    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.

  11. 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

  12. Platelets Play a Central Role in Sensitization to Allergen.

    Science.gov (United States)

    Amison, Richard T; Cleary, Simon; Riffo-Vasquez, Yanira; Bajwa, Maidda; Page, Clive P; Pitchford, Simon C

    2018-01-24

    Platelet activation occurs in patients with allergic inflammation, and platelets can be activated directly by allergen via an IgE-dependent process. Platelets activate antigen-presenting cells (APCs) such as CD11c+ dendritic cells (DCs) in vitro. Whilst CD11c+ DCs are requisite for allergen sensitization, the role of platelets in this process is unknown. We investigated whether platelets were necessary for allergen sensitization. Balb/c mice sensitised to ovalbumin (OVA), were exposed to subsequent aerosolized allergen (OVA challenge). We analysed lung CD11c+ cell activation, co-localization with platelets, and some other indices of inflammation. The role of platelets at the time of allergen sensitization was assessed through platelet depletion experiments restricted to the period of sensitization. Platelets co-localized with airway CD11c+ cells, and this association increased after allergen sensitization, and after subsequent allergen exposure. Temporary platelet depletion (>95%) at the time of allergen sensitization led to a suppression of IgE and IL-4 synthesis, and a decrease in the pulmonary recruitment of eosinophils, macrophages, and lymphocytes after subsequent allergen exposure. Furthermore, in mice previously depleted of platelets at the time of sensitization, the recovered platelet population were shown to have reduced expression of FcɛRI. Pulmonary CD11c+ cell recruitment was suppressed in these mice after allergen challenge, suggesting the migration of CD11c+ cells in vivo may be dependent on direct platelet recognition of allergen. Platelets are necessary for efficient host sensitization to allergen. This propagates the subsequent inflammatory response during secondary allergen exposure, and increases platelet association with airway CD11c+ cells.

  13. 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

  14. 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.

  15. 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.

  16. 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

  17. Platelets and their role in cancer evolution and immune system.

    Science.gov (United States)

    Karachaliou, Niki; Pilotto, Sara; Bria, Emilio; Rosell, Rafael

    2015-12-01

    Platelets are anucleate fragments formed from the cytoplasm of megakaryocytes and represent the smallest circulating hematopoietic cells. Thought for almost a century to possess solely hemostatic potentials, platelets actually play a much wider role in tissue regeneration and repair and interact intimately with tumor cells. On the one hand, tumor cells induce platelet aggregation, known to act as the trigger of cancer-associated thrombosis and on the other hand, platelets recruited to the tumor microenvironment interact directly with tumor cells favoring proliferation, and indirectly through the release of angiogenic and mitogenic proteins. Furthermore, platelets are immunosuppressive cells that protect metastatic cancer cells from surveillance by killer cells, nullifying the effects of immunotherapy.

  18. 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.

  19. Insulin resistance in platelets and monocytes

    NARCIS (Netherlands)

    Gerrits, A.J.

    2010-01-01

    Patients with type 2 diabetes have an increased risk of cardiovascular disease and suffer from thrombotic complications. The aim of the studies presented in this thesis is to elucidate the cause of the prothrombotic situation in type 2 diabetes patients. The studies were focused on platelets and

  20. 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.

  1. 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.

  2. 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 ...

  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. 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

  5. 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.

  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. 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

  8. Improving platelet transfusion safety: biomedical and technical considerations

    Science.gov (United States)

    Garraud, Olivier; Cognasse, Fabrice; Tissot, Jean-Daniel; Chavarin, Patricia; Laperche, Syria; Morel, Pascal; Lefrère, Jean-Jacques; Pozzetto, Bruno; Lozano, Miguel; Blumberg, Neil; Osselaer, Jean-Claude

    2016-01-01

    Platelet concentrates account for near 10% of all labile blood components but are responsible for more than 25% of the reported adverse events. Besides factors related to patients themselves, who may be particularly at risk of side effects because of their underlying illness, there are aspects of platelet collection and storage that predispose to adverse events. Platelets for transfusion are strongly activated by collection through disposal equipment, which can stress the cells, and by preservation at 22 °C with rotation or rocking, which likewise leads to platelet activation, perhaps more so than storage at 4 °C. Lastly, platelets constitutively possess a very large number of bioactive components that may elicit pro-inflammatory reactions when infused into a patient. This review aims to describe approaches that may be crucial to minimising side effects while optimising safety and quality. We suggest that platelet transfusion is complex, in part because of the complexity of the “material” itself: platelets are highly versatile cells and the transfusion process adds a myriad of variables that present many challenges for preserving basal platelet function and preventing dysfunctional activation of the platelets. The review also presents information showing - after years of exhaustive haemovigilance - that whole blood buffy coat pooled platelet components are extremely safe compared to the gold standard (i.e. apheresis platelet components), both in terms of acquired infections and of immunological/inflammatory hazards. PMID:26674828

  9. Evaluating platelet aggregation dynamics from laser speckle fluctuations.

    Science.gov (United States)

    Hajjarian, Zeinab; Tshikudi, Diane M; Nadkarni, Seemantini K

    2017-07-01

    Platelets are key to maintaining hemostasis and impaired platelet aggregation could lead to hemorrhage or thrombosis. We report a new approach that exploits laser speckle intensity fluctuations, emanated from a drop of platelet-rich-plasma (PRP), to profile aggregation. Speckle fluctuation rate is quantified by the speckle intensity autocorrelation, g 2 (t) , from which the aggregate size is deduced. We first apply this approach to evaluate polystyrene bead aggregation, triggered by salt. Next, we assess dose-dependent platelet aggregation and inhibition in human PRP spiked with adenosine diphosphate and clopidogrel. Additional spatio-temporal speckle analyses yield 2-dimensional maps of particle displacements to visualize platelet aggregate foci within minutes and quantify aggregation dynamics. These findings demonstrate the unique opportunity for assessing platelet health within minutes for diagnosing bleeding disorders and monitoring anti-platelet therapies.

  10. 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

  11. Fractal analysis of circulating platelets in type 2 diabetic patients.

    Science.gov (United States)

    Bianciardi, G; Tanganelli, I

    2015-01-01

    This paper investigates the use of computerized fractal analysis for objective characterization by means of transmission electron microscopy of the complexity of circulating platelets collected from healthy individuals and from type 2 diabetic patients, a pathologic condition in which platelet hyperreactivity has been described. Platelet boundaries were extracted by means of automatically image analysis. Local fractal dimension by box counting (measure of geometric complexity) was automatically calculated. The results showed that the platelet boundary observed by electron microscopy is fractal and that the shape of the circulating platelets is significantly more complex in the diabetic patients in comparison to healthy subjects (p fractal analysis of platelet shape by transmission electron microscopy can provide accurate, quantitative, data to study platelet activation in diabetes mellitus.

  12. 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

  13. Blood platelet counts, morphology and morphometry in lions, Panthera leo.

    Science.gov (United States)

    Du Plessis, L

    2009-09-01

    Due to logistical problems in obtaining sufficient blood samples from apparently healthy animals in the wild in order to establish normal haematological reference values, only limited information regarding the blood platelet count and morphology of free-living lions (Panthera leo) is available. This study provides information on platelet counts and describes their morphology with particular reference to size in two normal, healthy and free-ranging lion populations. Blood samples were collected from a total of 16 lions. Platelet counts, determined manually, ranged between 218 and 358 x 10(9)/l. Light microscopy showed mostly activated platelets of various sizes with prominent granules. At the ultrastructural level the platelets revealed typical mammalian platelet morphology. However, morphometric analysis revealed a significant difference (P < 0.001) in platelet size between the two groups of animals. Basic haematological information obtained in this study may be helpful in future comparative studies between animals of the same species as well as in other felids.

  14. Platelet associated IgG, platelet mean life span and treatment with intravenous immunoglobulin in idiopathic thrombocytopenic purpura

    Energy Technology Data Exchange (ETDEWEB)

    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 /sup 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.

  15. 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.

  16. Engagement of Platelet Toll-Like Receptor 9 by Novel Endogenous Ligands Promotes Platelet Hyper-Reactivity and Thrombosis

    Science.gov (United States)

    Panigrahi, Soumya; Ma, Yi; Hong, Li; Gao, Detao; West, Xiaoxia Z.; Salomon, Robert G.; Byzova, Tatiana V.; Podrez, Eugene A.

    2012-01-01

    Rationale A prothrombotic state and increased platelet reactivity are common in pathophysiological conditions associated with oxidative stress and infections. Such conditions are associated with an appearance of altered-self ligands in circulation that can be recognized by Toll-like receptors (TLR). Platelets express a number of TLR, including TLR9, however, the role of TLR in platelet function and thrombosis is poorly understood. Objective To investigate the biological activities of carboxy(alkylpyrrole) protein adducts (CAPs), an altered self-ligand generated in oxidative stress, on platelet function and thrombosis. Methods and Results In this study we show that CAPs represent novel unconventional ligands for TLR9. Furthermore, using human and murine platelets, we demonstrate that CAPs promote platelet activation, granule secretion, and aggregation in vitro and thrombosis in vivo via the TLR9/MyD88 pathway. Platelet activation by TLR9 ligands induces IRAK1 and AKT phosphorylation, and is Src kinase dependent. Physiological platelet agonists act synergistically with TLR9 ligands by inducing TLR9 expression on the platelet surface. Conclusions Our study demonstrates that platelet TLR9 is a functional platelet receptor that links oxidative stress, innate immunity, and thrombosis. PMID:23071157

  17. Increased platelet reactivity is associated with circulating platelet-monocyte complexes and macrophages in human atherosclerotic plaques.

    Science.gov (United States)

    Rutten, Bert; Tersteeg, Claudia; Vrijenhoek, Joyce E P; van Holten, Thijs C; Elsenberg, Ellen H A M; Mak-Nienhuis, Elske M; de Borst, Gert Jan; Jukema, J Wouter; Pijls, Nico H J; Waltenberger, Johannes; van Zonneveld, Anton Jan; Moll, Frans L; McClellan, Elizabeth; Stubbs, Andrew; Pasterkamp, Gerard; Hoefer, Imo; de Groot, Philip G; Roest, Mark

    2014-01-01

    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.

  18. 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.

  19. Decreased platelet count in children with epilepsy treated with valproate and its relationship to the immature platelet fraction.

    Science.gov (United States)

    Kurahashi, Hirokazu; Takami, Akiyoshi; Murotani, Kenta; Numoto, Shingo; Okumura, Akihisa

    2018-01-01

    This study examined relationships between valproate (VPA) and platelet count and immature platelet fraction (IPF). We compared the platelet count and IPF among three groups of children: those treated with VPA, those treated with other antiepileptic drugs (AEDs), and a reference group. IPF was measured using flow cytometry, and absolute immature platelet count (A-IPC) was calculated. The platelet count was significantly lower in the VPA group than in other AED and reference groups. In all groups, IPF was negatively correlated with platelet count. IPF was significantly higher in the VPA group than in the reference group, whereas A-IPC was similar among all groups. After stratification of the platelet count, IPF and A-IPC of the three groups did not differ significantly in any strata. No relationship was observed between serum VPA level and platelet count, IPF, or A-IPC. Our study suggests that VPA is associated with a decreased platelet count, although thrombocytopoiesis is not affected, even in children with a reduced platelet count. The suppression of platelet production in the bone marrow is unlikely to be the cause of thrombocytopenia in patients treated with VPA.

  20. SIGNIFICANCE OF PLATELET COUNT AND PLATELET INDICES IN PATIENTS WITH SOME THROMBOCYTOPENIC CONDITIONS

    Directory of Open Access Journals (Sweden)

    Omer Noureldaim Abdalla

    2016-01-01

    Full Text Available Background: Thrombocytopenia is one of the most frequent causes for hematologic consultation in the practice of medicine and can result from a wide variety of conditions. Objective: The study was conducted on behave of platelets count in tie with platelet volume indices to measure their consistency. Methods: The study was “prospective cross-sectional hospital based design” and conducted at Khartoum hospitals (A.Gasim, Jafar I A, and R.ICK. Studied populations texture has stipulated concurred diagnosis of heart disorders (HD, lymphoid neoplasms (LN, hypoplastic bone marrow (HPB, renal transplantation (RT, patients under chemotherapy (CT, and fully checked healthy Sudanese population (HSP. Platelet (PLT count and platelet volume index (PVI were measured using automated method of Sysmex KX-21N and the data was analyzed using SPSS. Results: does established (24 mean and standard for the study population among which (HSP was platelet distribution width (PDW (11.4±1.5 fl, mean platelet volume (MPV (9.3±0.8 fl, platelet large cell ratio (P- LCR (20.6±6.7% and PLT count (245±45 X109/L, and established correlations between PLT count and PVI in thrombocytopenic conditions. Conclusion: we conclude that, PVI has the ability to change from normal to higher or lower than (HSP in thrombocytopenic conditions and Sudanese has PVI mean lower than the mean of reference range, and there are inverse and reverse correlations between PLT count and PVI but not in (HSP and reverse correlation in between PVI except between PDW and P-LCR in (HPB

  1. 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

  2. Opposing Effects of Platelet-Activating Factor and Lyso-Platelet-Activating Factor on Neutrophil and Platelet ActivationS⃞

    OpenAIRE

    Welch, Emily J.; Naikawadi, Ram P.; Li, Zhenyu; Lin, Phoebe; Ishii, Satoshi; Shimizu, Takao; Tiruppathi, Chinnaswamy; Du, Xiaoping; Subbaiah, Papasani V.; Ye, Richard D.

    2008-01-01

    Platelet-activating factor (PAF) is a potent, bioactive phospholipid that acts on multiple cells and tissues through its G protein-coupled receptor (GPCR). PAF is not stored but is rapidly generated via enzymatic acetylation of the precursor 1-O-hexadecyl-2-hydroxy-sn-glycero-3-phosphocholine (lysoPAF). The bioactivity of PAF is effectively and tightly regulated by PAF acetylhydrolases, which convert PAF back to lysoPAF. Previous studies report that lysoPAF is an i...

  3. Determinants of ABH expression on human blood platelets.

    Science.gov (United States)

    Cooling, Laura L W; Kelly, Kathleen; Barton, James; Hwang, Debbie; Koerner, Theodore A W; Olson, John D

    2005-04-15

    Platelets express ABH antigens, which can adversely effect platelet transfusion recovery and survival in ABH-incompatible recipients. To date, there has been no large, comprehensive study comparing specific donor factors with ABH expression on platelet membranes and glycoconjugates. We studied ABH expression in 166 group A apheresis platelet donors by flow cytometry, Western blotting, and thin layer chromatography relative to donor age, sex, A1/A2 subgroup, and Lewis phenotype. Overall, A antigen on platelet membranes, glycoproteins, and glycosphingolipids was linked to an A1 red blood cell (RBC) phenotype. Among A1 donors, platelet ABH varied significantly between donors (0%-87%). Intradonor variability, however, was minimal, suggesting that platelet ABH expression is a stable, donor-specific characteristic, with 5% of A1 donors typing as either ABH high- or low-expressers. Group A2 donors, in contrast, possessed a Bombay-like phenotype, lacking both A and H antigens. Unlike RBCs, ABH expression on platelets may be determined primarily by H-glycosyltransferase (FUT1) activity. Identification of A2 and A1 low expressers may increase the availability and selection of crossmatched and HLA-matched platelets. Platelets from group A2 may also be a superior product for patients undergoing A/O major mismatch allogeneic progenitor cell transplantation.

  4. Interactions of periodontal pathogens with megakaryocytic cells and platelets

    Science.gov (United States)

    Andrews, A.M.; Haywood-Small, S.; Smith, T.; Stafford, P.

    2017-01-01

    ABSTRACT Introduction: Cardiovascular disease (CVD) is a leading cause of morbidity, accounting for around 17.3 million deaths worldwide. Recent studies have linked periodontitis to CVD with the periodonto-pathogens Porphyromonas gingivalis and Tannerella forsythia thought to contribute and exacerbate atherosclerosis through interactions with platelets. To date, while platelet activation following challenge with periodonto-pathogens has been reported, the underlying mechanisms of these interactions are yet to be elucidated. The aim of this study is to determine how periodonto-pathogens interact with platelets using both megakaryocytic cells and isolated platelets. Methods: To characterise expression levels of surface markers including ubiquitously expressed platelet-specific markers (CD41, CD42b) and platelet activation markers (CD62P, PAC-1), a multi-colour flow cytometry panel was developed using undifferentiated megakaryocytic cells CHRF-288-11 before validation using platelets isolated from healthy donors. Changes in levels of surface markers following bacterial challenge both with megakaryocytic cells and isolated platelets were determined using flow cytometry. Interaction with pathogens was visualised by platelet aggregometry and fluorescence microscopy using pathogen-specific antibodies. Results and conclusions: Both pathogens invaded megakaryocytic cells as visualised by immunofluorescence microscopy. The pathogens also bound platelets causing increased levels of aggregation and upregulated expression of activation markers including in CD62P in flow cytometric assays.

  5. Endocannabinoids Control Platelet Activation and Limit Aggregate Formation under Flow

    Science.gov (United States)

    De Angelis, Valentina; Koekman, Arnold C.; Weeterings, Cees; Roest, Mark; de Groot, Philip G.; Herczenik, Eszter; Maas, Coen

    2014-01-01

    Background The endocannabinoid system has previously been implicated in the regulation of neurons and inflammatory cells. Additionally, it has been reported that endocannabinoid receptors are present on circulating platelets, but there has been conflicting evidence on their contribution to platelet function. Objectives Our aim was to examine the role of endocannabinoids in platelet function in vitro and in vivo. Methods and Results We studied the effects of the well-characterized endogenous endocannabinoid anandamide on platelet aggregation in suspension, α-granule release, calcium mobilization, Syk phosphorylation, as well as platelet spreading and aggregate formation under flow. Anandamide inhibits platelet aggregation and α-granule release by collagen, collagen-derived peptide CRP-XL, ADP, arachidonic acid and thromboxane A2 analogue U46619. However, activation via thrombin receptor PAR-1 stays largely unaffected. Calcium mobilization is significantly impaired when platelets are stimulated with collagen or CRP-XL, but remains normal in the presence of the other agonists. In line with this finding, we found that anandamide prevents collagen-induced Syk phosphorylation. Furthermore, anandamide-treated platelets exhibit reduced spreading on immobilized fibrinogen, have a decreased capacity for binding fibrinogen in solution and show perturbed platelet aggregate formation under flow over collagen. Finally, we investigated the influence of Cannabis sativa consumption by human volunteers on platelet activation. Similar to our in vitro findings with anandamide, ex vivo collagen-induced platelet aggregation and aggregate formation on immobilized collagen under flow were impaired in whole blood of donors that had consumed Cannabis sativa. Conclusions Endocannabinoid receptor agonists reduce platelet activation and aggregate formation both in vitro and ex vivo after Cannabis sativa consumption. Further elucidation of this novel regulatory mechanism for platelet function

  6. Endocannabinoids control platelet activation and limit aggregate formation under flow.

    Directory of Open Access Journals (Sweden)

    Valentina De Angelis

    Full Text Available The endocannabinoid system has previously been implicated in the regulation of neurons and inflammatory cells. Additionally, it has been reported that endocannabinoid receptors are present on circulating platelets, but there has been conflicting evidence on their contribution to platelet function.Our aim was to examine the role of endocannabinoids in platelet function in vitro and in vivo.We studied the effects of the well-characterized endogenous endocannabinoid anandamide on platelet aggregation in suspension, α-granule release, calcium mobilization, Syk phosphorylation, as well as platelet spreading and aggregate formation under flow. Anandamide inhibits platelet aggregation and α-granule release by collagen, collagen-derived peptide CRP-XL, ADP, arachidonic acid and thromboxane A2 analogue U46619. However, activation via thrombin receptor PAR-1 stays largely unaffected. Calcium mobilization is significantly impaired when platelets are stimulated with collagen or CRP-XL, but remains normal in the presence of the other agonists. In line with this finding, we found that anandamide prevents collagen-induced Syk phosphorylation. Furthermore, anandamide-treated platelets exhibit reduced spreading on immobilized fibrinogen, have a decreased capacity for binding fibrinogen in solution and show perturbed platelet aggregate formation under flow over collagen. Finally, we investigated the influence of Cannabis sativa consumption by human volunteers on platelet activation. Similar to our in vitro findings with anandamide, ex vivo collagen-induced platelet aggregation and aggregate formation on immobilized collagen under flow were impaired in whole blood of donors that had consumed Cannabis sativa.Endocannabinoid receptor agonists reduce platelet activation and aggregate formation both in vitro and ex vivo after Cannabis sativa consumption. Further elucidation of this novel regulatory mechanism for platelet function may prove beneficial in the search

  7. Endocannabinoids control platelet activation and limit aggregate formation under flow.

    Science.gov (United States)

    De Angelis, Valentina; Koekman, Arnold C; Weeterings, Cees; Roest, Mark; de Groot, Philip G; Herczenik, Eszter; Maas, Coen

    2014-01-01

    The endocannabinoid system has previously been implicated in the regulation of neurons and inflammatory cells. Additionally, it has been reported that endocannabinoid receptors are present on circulating platelets, but there has been conflicting evidence on their contribution to platelet function. Our aim was to examine the role of endocannabinoids in platelet function in vitro and in vivo. We studied the effects of the well-characterized endogenous endocannabinoid anandamide on platelet aggregation in suspension, α-granule release, calcium mobilization, Syk phosphorylation, as well as platelet spreading and aggregate formation under flow. Anandamide inhibits platelet aggregation and α-granule release by collagen, collagen-derived peptide CRP-XL, ADP, arachidonic acid and thromboxane A2 analogue U46619. However, activation via thrombin receptor PAR-1 stays largely unaffected. Calcium mobilization is significantly impaired when platelets are stimulated with collagen or CRP-XL, but remains normal in the presence of the other agonists. In line with this finding, we found that anandamide prevents collagen-induced Syk phosphorylation. Furthermore, anandamide-treated platelets exhibit reduced spreading on immobilized fibrinogen, have a decreased capacity for binding fibrinogen in solution and show perturbed platelet aggregate formation under flow over collagen. Finally, we investigated the influence of Cannabis sativa consumption by human volunteers on platelet activation. Similar to our in vitro findings with anandamide, ex vivo collagen-induced platelet aggregation and aggregate formation on immobilized collagen under flow were impaired in whole blood of donors that had consumed Cannabis sativa. Endocannabinoid receptor agonists reduce platelet activation and aggregate formation both in vitro and ex vivo after Cannabis sativa consumption. Further elucidation of this novel regulatory mechanism for platelet function may prove beneficial in the search for new

  8. [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.

  9. 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.

  10. 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.

  11. Platelets aggregation in pathological conditions: role of local shear rates and platelet activation delay time.

    Science.gov (United States)

    Li, He; Zarif Khalili Yazdani, Alireza; Karniadakis, George

    2015-11-01

    Platelets play an essential role in the initiation and formation of a thrombus, however their detailed motion in blood vessels with complex geometries, such as in the aneurysmal vessel or stenotic vessel in atherosclerosis, has not been studied systematically. Here, we perform spectral element simulations (NEKTAR code) to obtain the 3D flow field in blood vessel with cavities, and we apply the force coupling method (FCM) to simulate the motion of platelets in blood flow. Specifically, simulations of platelets are performed in a 0.25 mm diameter circular blood vessel with 1 mm length. Corresponding coarse-grained molecular dynamics simulations are employed to provide input to the NEKTAR-FCM code. Simulations are conducted at several different Reynolds numbers (Re). An ellipsoid-shaped cavity is selected to intersect with the middle part of the circular vessel to represent the aneurysmal part of the blood vessel. Based on the simulation results, we quantify how the platelets motion and aggregation in the blood vessel cavities depend on Re, platelet activation delay time, and the geometry of the cavities.

  12. 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

  13. 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.

  14. 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.

  15. 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

  16. Platelet Glycoprotein lb-1X and Malignancy

    Science.gov (United States)

    2010-09-01

    therapy could benefit the breast cancer patient with malignant disease. Body Below we list the 3 Specific Aims from our original submission (blue font...Muller WJ and Pollard JW. Progression to malignancy in the polyoma middle T oncoprotein mouse breast cancer model provides a reliable model for human...08-1-0576 TITLE: Platelet Glycoprotein lb-1X and Malignancy PRINCIPAL INVESTIGATOR: Dr. Jerry Ware

  17. Platelet Glycoprotein lb-1X and Malignancy

    Science.gov (United States)

    2011-09-01

    independent of pregnancy makes this a useful model to study spontaneous metastasis [26]. To complete this aim, we obtained a mouse colony from Dr. Sandra...mice initiates the spontaneous development of a mammary adenocarcinoma by the age of 8- 10 weeks without pregnancy or any other stimuli. To examine if...patient with systemic lupus erythematosus. Am J Hematol 2001; 67:262-67. 20. Arthur JF, Dunkley S and Andrews RK. Platelet glycoprotein VI-related

  18. ABC transporters in megakaryopoiesis and platelet activity.

    Science.gov (United States)

    Wang, Wei; Buitrago, Lorena; Wang, Ying

    2017-08-01

    ATP-binding cassette (ABC) is a family of transporters that facilitates the translocation of substrates across cell membrane using its ATPase subunit. These transporters have key roles in multidrug resistance, lipid homeostasis, antigen processing, immunity, cell proliferation and hematopoiesis. Some ABC transporters are selectively expressed on megakaryocyte progenitor, megakaryocyte and its cellular fragment platelet. However, the role of ABC transporters in hemostasis and thrombosis were not well explored until recently. Studies of both human genetic diseases and genetically-manipulated animal models have greatly improved our understanding of ABC transporters in regulating hematopoiesis particularly megakaryopoiesis and/or platelet activity. Human genome wide association studies (GWAS) have also unraveled the association between ABC transporters and thrombopoiesis in general population. Therefore, this review aims to summarize the recent advances in our understanding of how ABC transporters regulate megakaryopoiesis and platelet activity, the underlining mechanisms and their association with atherosclerosis and atherothrombosis. Last, the emerging therapeutic targets to slow down atherosclerosis development and prevent atherothrombosis via ABC transporters or downstream pathways will also be discussed. Copyright © 2017 Elsevier Ltd. All rights reserved.

  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. Platelet rich plasma in ocular surface.

    Science.gov (United States)

    Riestra, A C; Alonso-Herreros, J M; Merayo-Lloves, J

    2016-10-01

    The use of platelet-rich preparations has experienced a significant increase in recent years due to its role in tissue-repair and regeneration. The aim of this study is to examine the available evidence regarding the application of plasma rich in growth factors, and its variations, on the ocular surface. A review is also presented on the effects of platelet-derived growth factors, the implications of the preparation methods, and the existing literature on the safety and efficacy of these therapies in ocular surface diseases. Despite the widespread use of platelet preparations there is no consensus on the most appropriate preparation method, and growth factors concentration vary with different systems. These preparations have been used in the treatment of ocular surface diseases, such as dry eye or persistent epithelial defects, among others, with good safety and efficacy profiles, but further studies are needed to compare to the currently available alternatives. Copyright © 2016 Sociedad Española de Oftalmología. Published by Elsevier España, S.L.U. All rights reserved.

  1. 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.

  2. 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...

  3. 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

  4. 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.

  5. Platelet Function Tests: A Review of Progresses in Clinical Application

    Directory of Open Access Journals (Sweden)

    Jae-Lim Choi

    2014-01-01

    Full Text Available The major goal of traditional platelet function tests has been to screen and diagnose patients who present with bleeding problems. However, as the central role of platelets implicated in the etiology of arterial thrombotic diseases such as myocardial infarction and stroke became widely known, platelet function tests are now being promoted to monitor the efficacy of antiplatelet drugs and also to potentially identify patients at increased risk of thrombosis. Beyond hemostasis and thrombosis, an increasing number of studies indicate that platelets play an integral role in intercellular communication, are mediators of inflammation, and have immunomodulatory activity. As new potential biomarkers and technologies arrive at the horizon, platelet functions testing appears to take on a new aspect. This review article discusses currently available clinical application of platelet function tests, placing emphasis on essential characteristics.

  6. 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...

  7. 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.

  8. 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.

  9. [Indications and surveillance of platelet transfusions in surgery].

    Science.gov (United States)

    Coffe, C; Bardiaux, L; Couteret, Y; Devillers, M; Leroy, M; Morel, P; Pouthier-Stein, F; Hervé, P

    1995-01-01

    Surgery, after hematology, is the biggest consumer of homologous platelet concentrates. Platelet transfusion is indicated to prevent or control bleeding associated with deficiencies in platelet number or function. In surgery, general patterns (in function of pre-surgery platelet count) can be adopted in most of the indications for platelets. In emergency situations, and in some particular cases (related to the patient, the type of operation, etc.), the transfusion procedure depends on the team's experience, the results of the available clinical and biological tests, and the drugs. Strict monitoring is required during the transfusion procedure. The efficacy of the transfusion must be controlled 1 h and 24 hours after the transfusion, and a number of factors must be assessed, namely the immunological impact of the transfusion (on red blood cells, leukocytes and platelets) and the occurrence of infectious diseases transmitted via transfusion. In addition, for a possible future transfusion, a strategy must be proposed.

  10. 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.

  11. 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...

  12. 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

  13. Allosteric Equilibria in the Binding of Fibrinogen to Platelets

    Science.gov (United States)

    de Cristofaro, Raimondo; Landolfi, Raffaele; de Candia, Erica; Castagnola, Massimo; di Cera, Enrico; Wyman, Jeffries

    1988-11-01

    The binding of fibrinogen to platelets occurs according to the law of mass action. The platelet receptor binds reversibly a single fibrinogen molecule and undergoes a conformational transition between two allosteric states, T and R, that differ in their affinity for fibrinogen. The equilibrium between the two forms is shifted by ADP toward the R (high-affinity) state, thus promoting the aggregation process. This model opens the way to consideration of allosteric modulation of the binding of fibrinogen to its platelet receptor.

  14. 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

  15. Are Platelets Cells? And if Yes, are They Immune Cells?

    Science.gov (United States)

    Garraud, Olivier; Cognasse, Fabrice

    2015-01-01

    Small fragments circulating in the blood were formally identified by the end of the nineteenth century, and it was suggested that they assisted coagulation via interactions with vessel endothelia. Wright, at the beginning of the twentieth century, identified their bone-marrow origin. For long, platelets have been considered sticky assistants of hemostasis and pollutants of blood or tissue samples; they were just cell fragments. As such, however, they were acknowledged as immunizing (to specific HPA and HLA markers): the platelet's dark face. The enlightened face showed that besides hemostasis, platelets contained factors involved in healing. As early as 1930s, platelets entered the arsenal of medicines were transfused, and were soon manipulated to become a kind of glue to repair damaged tissues. Some gladly categorized platelets as cells but they were certainly not fully licensed as such for cell physiologists. Actually, platelets possess almost every characteristic of cells, apart from being capable of organizing their genes: they have neither a nucleus nor genes. This view prevailed until it became evident that platelets play a role in homeostasis and interact with cells other than with vascular endothelial cells; then began the era of physiological and also pathological inflammation. Platelets have now entered the field of immunity as inflammatory cells. Does assistance to immune cells itself suffice to license a cell as an "immune cell"? Platelets prove capable of sensing different types of signals and organizing an appropriate response. Many cells can do that. However, platelets can use a complete signalosome (apart from the last transcription step, though it is likely that this step can be circumvented by retrotranscribing RNA messages). The question has also arisen as to whether platelets can present antigen via their abundantly expressed MHC class I molecules. In combination, these properties argue in favor of allowing platelets the title of immune cells.

  16. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Isaka, Yoshinari (Osaka National Hospital (Japan)); Kambayashi, Junichi; Kimura, Kazufumi (and others)

    1990-08-01

    We have studied 8 normal subjects, and 12 patients with idiopathic thrombocytopenic purpura whose platelet counts ranged from 9x10{sup 9}/L to 40x10{sup 9}/L. Autologous platelets labeled with {sup 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).

  18. 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)

  19. Validation of flow cytometric analysis of platelet function in patients with a suspected platelet function defect.

    Science.gov (United States)

    van Asten, I; Schutgens, R E G; Baaij, M; Zandstra, J; Roest, M; Pasterkamp, G; Huisman, A; Korporaal, S J A; Urbanus, R T

    2018-01-16

    Essentials The diagnosis of mild platelet function disorders (PFDs) is challenging. Validation of flow cytometric testing in patients with suspected PFDs is required. Flow cytometry has added value to light transmission aggregometry (LTA) in diagnosis of PFDs. There is fair agreement in diagnosing PFDs between LTA and flow cytometry. Background Light transmission aggregometry (LTA) is the most commonly used test for the diagnosis of platelet function disorders (PFDs), but has moderate sensitivity for mild PFDs. Flow cytometry has been recommended for additional diagnostics of PFDs but is not yet standardized as a diagnostic test. We developed a standardized protocol for flow cytometric analysis of platelet function that measures fibrinogen binding and P-selectin expression as platelet activation markers in response to agonist stimulation. Objectives To determine the additional value of flow cytometric platelet function testing to standard LTA screening in a cross-sectional cohort of patients with a suspected PFD. Methods Platelet function was assessed with flow cytometry and LTA in 107 patients suspected of a PFD in whom von Willebrand disease and coagulation factor deficiencies were excluded. Both tests were compared in terms of agreement and discriminative ability for diagnosing patients with PFDs. Results Out of 107 patients, 51 patients had an elevated bleeding score; 62.7% of the patients had abnormal platelet function measured with flow cytometry and 54.2% of the patients were abnormal based on LTA. There was fair agreement between LTA and flow cytometry (κ = 0.32). The discriminative ability of flow cytometric analysis in patients with an elevated bleeding score was good (AUC 0.82, 0.74-0.90), but moderate for LTA (AUC 0.70, 0.60-0.80). Both tests combined had a better discriminative ability (AUC 0.87, 0.80-0.94). Conclusion Flow cytometric analysis of platelet function has added value in diagnostics of PFDs in patients with unexplained bleeding tendency.

  20. 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.

  1. 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

  2. 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

  3. 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.

  4. A case of EDTA-related in vitro platelet degranulation.

    Science.gov (United States)

    Debus, Jérôme; Lemaire, Pierre; Cussac, Vincent; Sisiroi, Marinela; Pineau-Vincent, Fabienne

    2017-08-01

    A 71 year-old woman is admitted to Le Mans hospital center for management of a chronic skin lesion. She has no personal nor familial bleeding history and does not take any medication. In peripheral blood collected with EDTA (ethylene diamine tetra-acetate), the platelet count is elevated and the blood film shows uniformly grey platelets. In sodium citrate-collected blood, platelets show no abnormality. We describe an EDTA-related artifact that is not to be mistaken for grey platelet syndrome.

  5. 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.

  6. Aerobic exercise training lowers platelet reactivity and improves platelet sensitivity to prostacyclin in pre- and postmenopausal women

    DEFF Research Database (Denmark)

    Lundberg Slingsby, Martina Helena; Nyberg, Michael Permin; Egelund, Jon

    2017-01-01

    .7 (52.5-55.0) years old, participated in an intervention study: 3-month high-intensity supervised aerobic spinning-cycle training (1hr, x3/week). Basal platelet reactivity was analyzed in platelet rich plasma from venous blood as agonist-induced %aggregation. In a subgroup of 13 pre- and 14......BACKGROUND: The risk of atherothrombotic events increases after menopause. Regular physical activity has been shown to reduce platelet reactivity in younger women, but it is unknown how regular exercise affects platelet function after menopause. OBJECTIVES: To examine the effects of regular aerobic...... exercise in late pre- and recent postmenopausal women by testing basal platelet reactivity and platelet sensitivity to prostacyclin and nitric oxide. METHODS: 25 sedentary, but healthy, late premenopausal and 24 matched recently postmenopausal women, mean (95% confidence interval) 49.1 (48.2-49.9) and 53...

  7. Preeclampsia is not associated with altered platelet vasopressin binding and cytosolic Ca++ concentration

    NARCIS (Netherlands)

    van der Post, J. A.; Konijnenberg, A.; Boer, K.; Schaap, M. C.; van Boxtel, C. E.; Sturk, A.; Boer, G. J.; Swaab, D. F.

    1993-01-01

    OBJECTIVES: Preeclampsia is an important cause of fetal and maternal morbidity and mortality. Recently it was described that platelet cytosolic Ca++ levels could be used to screen for preeclampsia. The current study investigated platelet arginine vasopressin receptor characteristics, platelet

  8. Platelet-rich preparations to improve healing. Part II: platelet activation and enrichment, leukocyte inclusion, and other selection criteria.

    Science.gov (United States)

    Davis, Vicki L; Abukabda, Alaeddin B; Radio, Nicholas M; Witt-Enderby, Paula A; Clafshenkel, William P; Cairone, J Vito; Rutkowski, James L

    2014-08-01

    Multiple platelet-rich preparations have been reported to improve wound and bone healing, such as platelet-rich plasma (PRP) and platelet rich fibrin (PRF). The different methods employed during their preparation are important, as they influence the quality of the product applied to a wound or surgical site. Besides the general protocol for preparing the platelet-rich product (discussed in Part 1 of this review), multiple choices need to be considered during its preparation. For example, activation of the platelets is required for the release and enmeshment of growth factors, but the method of activation may influence the resulting matrix, growth factor availability, and healing. Additionally, some methods enrich leukocytes as well as platelets, but others are designed to be leukocyte-poor. Leukocytes have many important roles in healing and their inclusion in PRP results in increased platelet concentrations. Platelet and growth factor enrichment reported for the different types of platelet-rich preparations are also compared. Generally, TGF-β1 and PDGF levels were higher in preparations that contain leukocytes compared to leukocyte-poor PRP. However, platelet concentration may be the most reliable criterion for comparing different preparations. These and other criteria are described to help guide dental and medical professionals, in large and small practices, in selecting the best procedures for their patients. The healing benefits of platelet-rich preparations along with the low risk and availability of simple preparation procedures should encourage more clinicians to incorporate platelet-rich products in their practice to accelerate healing, reduce adverse events, and improve patient outcomes.

  9. Mechanism of platelet functional changes and effects of anti-platelet agents on in vivo hemostasis under different gravity conditions.

    Science.gov (United States)

    Li, Suping; Shi, Quanwei; Liu, Guanglei; Zhang, Weilin; Wang, Zhicheng; Wang, Yuedan; Dai, Kesheng

    2010-05-01

    Serious thrombotic and hemorrhagic problems or even fatalities evoked by either microgravity or hypergravity occur commonly in the world. We recently reported that platelet functions are inhibited in microgravity environments and activated under high-G conditions, which reveals the pathogenesis for gravity change-related hemorrhagic and thrombotic diseases. However, the mechanisms of platelet functional variations under different gravity conditions remain unclear. In this study we show that the amount of filamin A coimmunoprecipitated with GPIbalpha was enhanced in platelets exposed to modeled microgravity and, in contrast, was reduced in 8 G-exposed platelets. Hypergravity induced actin filament formation and redistribution, whereas actin filaments were reduced in platelets treated with modeled microgravity. Furthermore, intracellular Ca2+ levels were elevated by hypergravity. Pretreatment of platelets with the cell-permeable Ca2+ chelator BAPTA-AM had no effect on cytoskeleton reorganization induced by hypergravity but significantly reduced platelet aggregation induced by ristocetin/hypergravity. Two anti-platelet agents, aspirin and tirofiban, effectively reversed the shortened tail bleeding time and reduced the death rate of mice exposed to hypergravity. Furthermore, the increased P-selectin surface expression was obviously reduced in platelets from mice treated with aspirin/hypergravity compared with those from mice treated with hypergravity alone. These data suggest that the actin cytoskeleton reorganization and intracellular Ca2+ level play key roles in the regulation of platelet functions in different gravitational environments. The results with anti-platelet agents not only further confirm the activation of platelets in vivo but also suggest a therapeutic potential for hypergravity-induced thrombotic diseases.

  10. Human platelets frozen with glycerol in liquid nitrogen: biological and clinical aspects.

    Science.gov (United States)

    Herve, P; Potron, G; Droule, C; Beduchaud, M P; Masse, M; Coffe, C; Bosset, J F; Peters, A

    1981-01-01

    Platelets were frozen using glycerol (3% in plasma) as a cryoprotective agent, a rapid cooling rate, and liquid nitrogen for storage. The cryopreserved platelets were thawed at 42 C and infused without washing. The results indicate that the quality of the thawed platelets is equivalent to platelets stored for 24 to 48 hours at room temperature. The availability of HLA phenotyped leukocyte poor platelets can reduce the frequency of sensitization to strong antigens and provide clinically effective platelets for alloimmunized patients.

  11. Role of the recombinant non-integrin platelet collagen receptor P65 on platelet activation induced by convulxin.

    Science.gov (United States)

    Francischetti, I M; Chiang, T M; Guimarães, J A; Bon, C

    2000-04-21

    Convulxin (Cvx) isolated from Crotalus durissus terrificus venom selectively binds with a high affinity to platelets and induces platelet aggregation by a mechanism that resembles that induced by collagen. Taking advantage that P65 has been recently cloned and expressed as a recombinant soluble protein (rec-P65), we examined the role of this non-integrin collagen receptor in platelet activation induced by Cvx. Rec-P65 blocked platelet adhesion to collagen-coated surfaces and inhibited platelet aggregation and ATP secretion induced by type I collagen. On the other hand, rec-P65 did not inhibit platelet aggregation and ATP secretion induced by Cvx, and it did not affect platelet adhesion to Cvx. In addition, ligand-blotting indicated that the Cvx binding to the collagen receptor GPVI was preserved in the presence of rec-P65. These observations indicate that P65 does not play a significant role in platelet activation by Cvx; in contrast, platelet response to collagen involves multiple receptors. Copyright 2000 Academic Press.

  12. Effect of safflower yellow on platelet activating factor mediated platelet activation in patients with coronary heart disease

    Directory of Open Access Journals (Sweden)

    Damin Huang

    2012-06-01

    Full Text Available The platelet aggregation and 5-HT release by washed platelet from coronary heart disease patients following platelet activating factor (PAF treatment were detected by turbidimetry and O-phthalaldehyde assay. The free calcium concentration in the platelets was measured with the fura-2/AM probe fluorescent technique. Results showed safflower yellow could inhibit the PAF induced washed platelet aggregation and 5-HT release, which were in a safflor-yellow-dose dependent manner. When the PAF was 2.0×10-9 mol/L, the inhibition rate of platelet aggregation was 26.2%, 41.3%, 58.1%, 81.2%, and the inhibition rate of 5-HT release was 3.7%, 11.9%, 29.9% and 54.4% after treatment with safflower yellow at 0.21, 0.42, 0.85 and 1.69 g/L, respectively. The study concludes safflower yellow can inhibit the PAF induced platelet aggregation, 5-HT release by platelets and elevation of free calcium in platelets.

  13. Physiopathology of blood platelets and development of platelet substitutes. Progress report, August 1, 1974--July 31, 1975

    International Nuclear Information System (INIS)

    Baldini, M.G.

    1975-01-01

    Progress is reported on investigations of methods for the storage of human blood platelets. Good results were obtained when platelets were frozen using 5 percent dimethyl sulfoxide (DMSO) as a cryoprotective agent. There was no evidence of toxic effects of trace amounts of DMSO in experimental animals. Blood platelet storage at 22 0 C with nucleotide additives in the storage medium was also investigated. The effects of x irradiation at doses varying from 100 to 1000 R on the aggregation of blood platelets following exposure in vitro and the effect of Vitamin E as an antiaggregating agent were studied. (U.S.)

  14. Extracellular histones promote thrombin generation through platelet-dependent mechanisms: involvement of platelet TLR2 and TLR4

    Science.gov (United States)

    Semeraro, Fabrizio; Ammollo, Concetta T.; Morrissey, James H.; Dale, George L.; Friese, Paul; Esmon, Naomi L.

    2011-01-01

    The release of histones from dying cells is associated with microvascular thrombosis and, because histones activate platelets, this could represent a possible pathogenic mechanism. In the present study, we assessed the influence of histones on the procoagulant potential of human platelets in platelet-rich plasma (PRP) and in purified systems. Histones dose-dependently enhanced thrombin generation in PRP in the absence of any trigger, as evaluated by calibrated automated thrombinography regardless of whether the contact phase was inhibited. Activation of coagulation required the presence of fully activatable platelets and was not ascribable to platelet tissue factor, whereas targeting polyphosphate with phosphatase reduced thrombin generation even when factor XII (FXII) was blocked or absent. In the presence of histones, purified polyphosphate was able to induce thrombin generation in plasma independently of FXII. In purified systems, histones induced platelet aggregation; P-selectin, phosphatidylserine, and FV/Va expression; and prothrombinase activity. Blocking platelet TLR2 and TLR4 with mAbs reduced the percentage of activated platelets and lowered the amount of thrombin generated in PRP. These data show that histone-activated platelets possess a procoagulant phenotype that drives plasma thrombin generation and suggest that TLR2 and TLR4 mediate the activation process. PMID:21673343

  15. Neonatal Platelet Transfusions and Future Areas of Research.

    Science.gov (United States)

    Sola-Visner, Martha; Bercovitz, Rachel S

    2016-10-01

    Thrombocytopenia affects approximately one fourth of neonates admitted to neonatal intensive care units, and prophylactic platelet transfusions are commonly administered to reduce bleeding risk. However, there are few evidence-based guidelines to inform clinicians' decision-making process. Developmental differences in hemostasis and differences in underlying disease processes make it difficult to apply platelet transfusion practices from other patient populations to neonates. Thrombocytopenia is a risk factor for common preterm complications such as intraventricular hemorrhage; however, a causal link has not been established, and platelet transfusions have not been shown to reduce risk of developing intraventricular hemorrhage. Platelet count frequently drives the decision of whether to transfuse platelets, although there is little evidence to demonstrate what a safe platelet nadir is in preterm neonates. Current clinical assays of platelet function often require large sample volumes and are not valid in the setting of thrombocytopenia; however, evaluation of platelet function and/or global hemostasis may aid in the identification of neonates who are at the highest risk of bleeding. Although platelets' primary role is in establishing hemostasis, platelets also carry pro- and antiangiogenic factors in their granules. Aberrant angiogenesis underpins common complications of prematurity including intraventricular hemorrhage and retinopathy of prematurity. In addition, platelets play an important role in host immune defenses. Infectious and inflammatory conditions such as sepsis and necrotizing enterocolitis are commonly associated with late-onset thrombocytopenia in neonates. Severity of thrombocytopenia is correlated with mortality risk. The nature of this association is unclear, but preclinical data suggest that thrombocytopenia contributes to mortality rather than simply being a proxy for disease severity. Neonates are a distinct patient population in whom

  16. Platelet-activating factor podoplanin: from discovery to drug development.

    Science.gov (United States)

    Takemoto, Ai; Miyata, Kenichi; Fujita, Naoya

    2017-06-01

    Tumor cell-induced platelet aggregation facilitates hematogenous metastasis by promoting tumor embolization, preventing immunological assaults and shear stress, and the platelet-releasing growth factors support tumor growth and invasion. Podoplanin, also known as Aggrus, is a type I transmembrane mucin-like glycoprotein and is expressed on wide range of tumor cells. Podoplanin has a role in platelet aggregation and metastasis formation through the binding to its platelet receptor, C-type lectin-like receptor 2 (CLEC-2). The podoplanin research was originally started from the cloning of highly metastatic NL-17 subclone from mouse colon 26 cancer cell line and from the establishment of 8F11 monoclonal antibody (mAb) that could neutralize NL-17-induced platelet aggregation and hematogenous metastasis. Later on, podoplanin was identified as the antigen of 8F11 mAb, and its ectopic expression brought to cells the platelet-aggregating abilities and hematogenous metastasis phenotypes. From the 8F11 mAb recognition epitopes, podoplanin is found to contain tandemly repeated, highly conserved motifs, designated platelet aggregation-stimulating (PLAG) domains. Series of analyses using the cells expressing the mutants and the established neutralizing anti-podoplanin mAbs uncovered that both PLAG3 and PLAG4 domains are associated with the CLEC-2 binding. The neutralizing mAbs targeting PLAG3 or PLAG4 could suppress podoplanin-induced platelet aggregation and hematogenous metastasis through inhibiting the podoplanin-CLEC-2 binding. Therefore, these domains are certainly functional in podoplanin-mediated metastasis through its platelet-aggregating activity. This review summarizes the platelet functions in metastasis formation, the role of platelet aggregation-inducing factor podoplanin in pathological and physiological situations, and the possibility to develop podoplanin-targeting drugs in the future.

  17. Basic study of platelet labeling with 111In-oxine

    International Nuclear Information System (INIS)

    Yui, Tokuo; Uchida, Tatsumi; Matsuda, Shin; Muroi, Shuichi; Tanaka, Tetsugoro

    1981-01-01

    Indium-111-oxine has recently been suggested as a new isotopic labeling agent of platelets. In this paper, the results on the investigation of in vitro labeling of human platelets with In-111-oxine and those of platelet kinetics in rats are presented. Based on the findings of those studies, the protocol of human platelet labeling with In-111-oxine for clinical use was established. All operations should be carried out with sterile techniques at 20 - 25 0 C. 1) Forty four ml venous blood is drawn into a 50 ml polystyrene syringe containing 6 ml ACD-A. 2) The blood is transferred to a 50 ml tube and centrifuged at 300 g for 15 min. 3) Supernatant platelet rich plasma (PRP) is transferred to other 50 ml tube. Then, the pH is adjusted to 6.5 by addition of 1 ml ACD-A per 20 ml PRP. 4) Platelets are sedimented by centrifuging at 1,500 g for 15 min and resuspended in 3 ml ACD-A-saline solution (pH 6.5). 5) Three hundreds μCi of In-111-oxine is added to the platelet suspension. The mixture is incubated for 20 min at room temperature. 6) About 15 ml of the platelet poor autologous plasma (PPP) is added into the incubated mixture, followed by the sedimentation of labeled platelets (1,500 g, 15 min). 7) The labeled platelets are suspended in 10 ml PPP and the contaminating red cells are sedimented by centrifuging at 200 g for 5 min. 8) One hundred and fifty μCi of labeled platelet suspension is injected to the patient intravenously. The labeling efficiency in this method was 62 +- 5% (mean +- 1S.D., n = 6). (author)

  18. Glutamate release from platelets: exocytosis versus glutamate transporter reversal.

    Science.gov (United States)

    Kasatkina, Ludmila A; Borisova, Tatiana A

    2013-11-01

    Platelets express neuronal and glial glutamate transporters EAAT 1-3 in the plasma membrane and vesicular glutamate transporters VGLUT 1,2 in the membrane of secretory granules. This study is focused on the assessment of non-exocytotic glutamate release, that is, the unstimulated release, heteroexchange and glutamate transporter reversal in platelets. Using the glutamate dehydrogenase assay, the absence of unstimulated release of endogenous glutamate from platelets was demonstrated, even after inhibition of glutamate transporters and cytoplasmic enzyme glutamine synthetase by dl-threo-β-benzyloxyaspartate and methionine sulfoximine, respectively. Depolarization of the plasma membrane by exposure to elevated [K(+)] did not induce the release of glutamate from platelets that was shown using the glutamate dehydrogenase assay and radiolabeled l-[(14)C]glutamate. Glutamate efflux by means of heteroexchange with transportable inhibitor of glutamate transporters dl-threo-β-hydroxyaspartate (dl-THA) was not observed. Furthermore, the protonophore cyanide-p-trifluoromethoxyphenyl-hydrazon (FCCP) and inhibitor of V-type H(+)-ATPase bafilomycin A1 also failed to stimulate the release of glutamate from platelets. However, exocytotic release of glutamate from secretory granules in response to thrombin stimulation was not prevented by elevated [K(+)], dl-THA, FCCP and bafilomycin A1. In contrast to nerve terminals, platelets cannot release glutamate in a non-exocytotic manner. Heteroexchange, transporter-mediated and unstimulated release of glutamate are not inherent to platelets. Therefore, platelets may be used as a peripheral marker/model for the analysis of glutamate uptake by brain nerve terminals only (direct function of transporters), whereas the mechanisms of glutamate release are different in platelets and nerve terminals. Glutamate is released by platelets exclusively by means of exocytosis. Also, reverse function of vesicular glutamate transporters of platelets is

  19. Platelets and their chemokines in atherosclerosis – clinical applications

    Directory of Open Access Journals (Sweden)

    Philipp evon Hundelshausen

    2014-08-01

    Full Text Available The concept of platelets as important players in the process of atherogenesis has become increasingly accepted due to accumulating experimental and clinical evidence. Despite the progress in understanding the molecular details of atherosclerosis, particularly by using animal models, the inflammatory and thrombotic roles of activated platelet s especially in the human system remain difficult to dissect, as often only the complications of atherosclerosis i.e. stroke and myocardial infarction are definable but not the plaque burden.Platelet indices including platelet count and mean platelet volume and soluble mediators released by activated platelets are associated with atherosclerosis. The chemokine CXCL4 has multiple atherogenic activities e.g. altering the differentiation of T cells and macrophages by inhibiting neutrophil and monocyte apoptosis and by increasing the uptake of oxLDL and synergizing with CCL5. CCL5 is released and deposited on endothelium by activated platelets thereby triggering atherogenic monocyte recruitment, which can be attenuated by blocking the corresponding chemokine receptor CCR5. Atheroprotective and plaque stabilizing properties are attributed to CXCL12, which plays an important role in regenerative processes by attracting progenitor cells. Its release from luminal attached platelets accelerates endothelial healing after injury. Platelet surface molecules GPIIb/IIIa, GP1bα, P-selectin, JAM-A and the CD40/CD40L dyade are crucially involved in the interaction with endothelial cells, leukocytes and matrix molecules affecting atherogenesis. Beyond the effects on the arterial inflammatory infiltrate, platelets affect cholesterol metabolism by binding, modifying and endocytosing LDL particles via their scavenger receptors and contribute to the formation of lipid laden macrophages. Current medical therapies for the prevention of atherosclerotic therapies enable the elucidation of mechanisms linking platelets to inflammation

  20. Are Platelets Cells? And if Yes, Are They Immune Cells?

    Directory of Open Access Journals (Sweden)

    Fabrice eCOGNASSE

    2015-02-01

    Full Text Available Small fragments circulating in the blood were formally identified by the end of the 19th century, and it was suggested that they assisted coagulation via interactions with vessel endothelia. Wright, at the beginning of the 20th century, identified their bone-marrow origin. For long, platelets have been considered sticky assistants of hemostasis and pollutants of blood or tissue samples; they were just cell fragments. As such however, they were acknowledged as immunizing (to specific HPA and HLA markers: the platelet’s dark face. The enlightened face showed that besides hemostasis, platelets contained factors involved in healing. As early as the 1930s, platelets entered the arsenal of medicines; were transfused, and were soon manipulated to become a kind of glue to repair damaged tissues. Some gladly categorized platelets as cells but they were certainly not fully licensed as such for cell physiologists. Actually, platelets possess almost every characteristic of cells, apart from being capable of organizing their genes: they have neither a nucleus nor genes. This view prevailed until it became evident that platelets play a role in homeostasis and interact with cells other than with vascular endothelial cells; then began the era of physiological and also pathological inflammation. Platelets have now entered the field of immunity as inflammatory cells. Does assistance to immune cells itself suffice to license a cell as an immune cell? Platelets prove capable of sensing different types of signals and organizing an appropriate response. Many cells can do that. However, platelets can use a complete signalosome (apart from the last transcription step, though it is likely that this step can be circumvented by retrotranscribing RNA messages. The question has also arisen as to whether platelets can present antigen via their abundantly expressed MHC class I molecules. In combination, these properties argue in favor of allowing platelets the title of

  1. Platelet concentration in platelet-rich plasma affects tenocyte behavior in vitro.

    Science.gov (United States)

    Giusti, Ilaria; D'Ascenzo, Sandra; Mancò, Annalisa; Di Stefano, Gabriella; Di Francesco, Marianna; Rughetti, Anna; Dal Mas, Antonella; Properzi, Gianfranco; Calvisi, Vittorio; Dolo, Vincenza

    2014-01-01

    Since tendon injuries and tendinopathy are a growing problem, sometimes requiring surgery, new strategies that improve conservative therapies are needed. Platelet-rich plasma (PRP) seems to be a good candidate by virtue of its high content of growth factors, most of which are involved in tendon healing. This study aimed to evaluate if different concentrations of platelets in PRP have different effects on the biological features of normal human tenocytes that are usually required during tendon healing. The different platelet concentrations tested (up to 5 × 10(6) plt/µL) stimulated differently tenocytes behavior; intermediate concentrations (0.5 × 10(6), 1 × 10(6) plt/µL) strongly induced all tested processes (proliferation, migration, collagen, and MMPs production) if compared to untreated cells; on the contrary, the highest concentration had inhibitory effects on proliferation and strongly reduced migration abilities and overall collagen production but, at the same time, induced increasing MMP production, which could be counterproductive because excessive proteolysis could impair tendon mechanical stability. Thus, these in vitro data strongly suggest the need for a compromise between extremely high and low platelet concentrations to obtain an optimal global effect when inducing in vivo tendon healing.

  2. The influence of environmental variables on platelet concentration in horse platelet-rich plasma.

    Science.gov (United States)

    Rinnovati, Riccardo; Romagnoli, Noemi; Gentilini, Fabio; Lambertini, Carlotta; Spadari, Alessandro

    2016-07-04

    Platelet-rich plasma (PRP) commonly refers to blood products which contain a higher platelet (PLT) concentration as compared to normal plasma. Autologous PRP has been shown to be safe and effective in promoting the natural processes of soft tissue healing or reconstruction in humans and horses. Variability in PLT concentration has been observed in practice between PRP preparations from different patients or from the same individual under different conditions. A change in PLT concentration could modify PRP efficacy in routine applications. The aim of this study was to test the influence of environmental, individual and agonistic variables on the PLT concentration of PRP in horses. Six healthy Standardbred mares were exposed to six different variables with a one-week washout period between variables, and PRP was subsequently obtained from each horse. The variables were time of withdrawal during the day (morning/evening), hydration status (overhydration/dehydration) treatment with anti-inflammatory drugs and training periods on a treadmill. The platelet concentration was significantly higher in horses treated with a non-steroidal anti-inflammatory drug (P = 0.03). The leukocyte concentration increased 2-9 fold with respect to whole blood in the PRP which was obtained after exposure to all the variable considered. Environmental variation in platelet concentration should be taken into consideration during PRP preparation.

  3. The mitochondrial membrane potential in human platelets: a sensitive parameter for platelet quality

    NARCIS (Netherlands)

    Verhoeven, Arthur J.; Verhaar, Robin; Gouwerok, Eric G. W.; de Korte, Dirk

    2005-01-01

    BACKGROUND: Deterioration of platelet (PLT) quality during storage is accompanied by an increase in lactate production, indicating a decrease in mitochondrial function. In this study, the optimal conditions under which the fluorescent dye JC-1 can be used to detect changes in mitochondrial function

  4. Platelet activation and platelet-leukocyte interaction in dogs naturally infected with Babesia rossi

    DEFF Research Database (Denmark)

    Goddard, Amelia; Leisewitz, Andrew L; Kristensen, Annemarie Thuri

    2015-01-01

    EDTA as anticoagulant. Activated platelets and PLA formation were detected by measuring surface expression of P-selectin (CD62P) on platelets, monocytes and neutrophils. Of the Babesia-infected dogs, 29 survived and seven died. The percentage of CD62P-positive monocytes was significantly higher (P = 0.......036) in the Babesia-infected dogs (54%) than in healthy control dogs (35.3%). However, there were no significant differences between the Babesia-infected and control groups for CD62P-positive platelets (4.9% and 1.2%, respectively) and CD62P-positive neutrophils (28.3% and 17.9%, respectively). The percentage of CD62...... groups for the percentage of CD62P-positive platelets (survivors 4.8%; non-survivors 5.3%; controls 1.2%) or CD62P-positive neutrophils (survivors 31.6%; non-survivors 5.6%; controls 17.9%). In conclusion, Babesia-infected dogs, specifically dogs that survived, had a significantly increased percentage...

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

    Science.gov (United States)

    1986-07-01

    acid with an increased rate of glycogenolysis , glycolysis, protein synthesis and glycogen synthesis. No difference in total lipid or lipid synthesis...Minter, F. and Ingram, M. 1971. Platelet volume: Density relationships in normal and acutely bled dogs . Br. J. Haematol. 20:55. Mundschenk, D., Connelly

  6. Pregnancies with Platelet Count Lower Than 70000 Platelets/μl

    Directory of Open Access Journals (Sweden)

    Semih Mun

    2006-08-01

    CONCLUSION: If thrombocyte count of a pregnant is not less than 70000/μl and her symptoms are not related with thrombocytopenia then only follow up for platelet counts is sufficient in pregnancy. However if it is less than 70000/μl, treatment of thrombocytopenia and strict follow up of patient is necessary.

  7. Pressure-aided transfusion of platelets: does it affect the platelets?

    DEFF Research Database (Denmark)

    Fischer-Nielsen, Anne; Stissing, Trine; Maansson, Charlotte

    2010-01-01

    In massively bleeding patients, pressure infusers are used for transfusion of red blood cells and plasma but not for platelets (PLTs) due to an assumed negative effect on the PLTs. This study examined whether pressure-aided in vitro transfusion affected the number, activation state, and/or function...

  8. Mean platelet volume, neutrophil to lyphocyte ratio and platelet to lymphocyte ratio in psoriasis

    Directory of Open Access Journals (Sweden)

    Mehmet Ünal

    2015-06-01

    Full Text Available Background and Design: It has been demonstrated that ratio of neutrophil and platelet count systemic inflammation and is associated with prognosis of many cardiovascular diseases, malignates and chronic inflammatory diseases.As far as it is known, there are no studies investigating neutrophil/lymphocyeratio(NLR, platelet/lymphocyte ratio(PLR and mean platelet volume(MPV values together within the context of psoriasis, a chronic and systemic inflammatory disease. Materials and Methods: 320 patients followed up in our polyclinic with psoriasis vulgaris and 200 healthy persons were evaluated in the study. Results: Leukocyte, neutrophil, platelet, MPV, NLR and PLR values in patients with psoriasis were significantly higher, and lymphocyte count, on the other hand, was significantly lower than those of the control group. No significant difference was found between MPV, NLR and PLR values of patients with or without a family history, nail and joint involvement. Conclusions: These parameters may be made use of as cheap and easily applicable methods in predicting which psoriasis patients are under the risk of cardiovascular disease. PLR is a better inflammation marker than MPV and NLR in patients with psoriasis. We did not observe a significant relationship between MPV, NLR and PLR values and such disease characteristics as severity of disease, joint involvement, nail involvement and duration of disease in patients with psoriasis. So, we believe that there is little information on the extent to which MPV,NLR and PLR might be useful regarding these characteristics.

  9. Effect of platelet orientation on the properties of alumina platelet zirconia matrix composites

    DEFF Research Database (Denmark)

    Toft Sørensen, O.; Li, W.-Y.

    1996-01-01

    Platelet alignment in Al2O3pl - TZ3YS composites formed by injection moulding, slip casting, and tape casting, has been examined. Mechanical properties have been determined in terms of flexural strength and fracture toughness, with respect to materials formed by different techniques...

  10. Clot lysis time in platelet-rich plasma: method assessment, comparison with assays in platelet-free and platelet-poor plasmas, and response to tranexamic acid.

    Science.gov (United States)

    Panes, Olga; Padilla, Oslando; Matus, Valeria; Sáez, Claudia G; Berkovits, Alejandro; Pereira, Jaime; Mezzano, Diego

    2012-01-01

    Fibrinolysis dysfunctions cause bleeding or predisposition to thrombosis. Platelets contain several factors of the fibrinolytic system, which could up or down regulate this process. However, the temporal relationship and relative contributions of plasma and platelet components in clot lysis are mostly unknown. We developed a clot lysis time (CLT) assay in platelet-rich plasma (PRP-CLT, with and without stimulation) and compared it to a similar one in platelet-free plasma (PFP) and to another previously reported test in platelet-poor plasma (PPP). We also studied the differential effects of a single dose of tranexamic acid (TXA) on these tests in healthy subjects. PFP- and PPP-CLT were significantly shorter than PRP-CLT, and the three assays were highly correlated (p plasma PAI-1, von Willebrand factor, fibrinogen, LDL-cholesterol, and triglycerides (p platelet aggregation/secretion, platelet counts, and pro-coagulant tests to explore factor X activation by platelets, PRP clotting time, and thrombin generation in PRP. Among all the studied variables, PFP-CLT was independently associated with plasma PAI-1, LDL-cholesterol, and triglycerides and, additionally, stimulated PRP-CLT was also independently associated with plasma fibrinogen. A single 1 g dose of TXA strikingly prolonged all three CLTs, but in contrast to the results without the drug, the lysis times were substantially shorter in non-stimulated or stimulated PRP than in PFP and PPP. This standardized PRP-CLT may become a useful tool to study the role of platelets in clot resistance and lysis. Our results suggest that initially, the platelets enmeshed in the clot slow down the fibrinolysis process. However, the increased clot resistance to lysis induced by TXA is overcome earlier in platelet-rich clots than in PFP or PPP clots. This is likely explained by the display of platelet pro-fibrinolytic effects. Focused research is needed to disclose the mechanisms for the relationship between CLT and plasma

  11. ACHILLES TENDON RUPTURE AND PLATELET RICH PLASMA

    Directory of Open Access Journals (Sweden)

    Pietro Zedde

    2012-03-01

    Full Text Available Achilles tendon rupture is currently one of the most frequent injuries in athletes. Such rupture may be caused by a sudden dorsiflexion of the ankle, pushing off with the weight bearing forefoot while extending the knee or violent dorsiflexion of a plantar flexed foot. The treatment goal consists of restoring the normal tendon length and tension, as well as the function and strength of the gastrocnemius-soleus complex. The biological repair process can be enhanced in all stages of recovery with the use of PRP (Platelet Rich Plasma without any side effects.

  12. Platelet activation and platelet-leukocyte interaction in β-thalassemia/hemoglobin E patients with marked nucleated erythrocytosis.

    Science.gov (United States)

    Keawvichit, Rassamon; Khowawisetsut, Ladawan; Chaichompoo, Porntip; Polsrila, Korakot; Sukklad, Suchana; Sukapirom, Kasama; Khuhapinant, Archrob; Fucharoen, Suthat; Pattanapanyasat, Kovit

    2012-11-01

    Patients with thalassemia, an inherited hemolytic anemia, have increased risk of hypercoagulable complications. A whole blood flow cytometric (FCM) method has been used for studies of platelet activation and platelet-leukocyte aggregation in these patients. However, this FCM method presents technical difficulties because of the high proportion of immature red blood cells (RBCs) in these patients. A protocol for the simultaneous measurement of platelet activation and their aggregation with leukocyte populations in whole blood using four-color FCM which excluded immature RBC was devised, and evaluated for the evaluation of platelet function in patients with β-thalassemia/hemoglobin E (HbE). Whole blood from these patients and from healthy volunteers was stained for platelet activation and platelet-leukocyte aggregates using anti-CD42a, anti-CD62P, anti-CD45 and glycophorin A (GPA) conjugated with different fluorochromes. Our FCM method is simple, effective and based on the assumption that GPA is present on all immature RBCs, but is not expressed on CD45⁺ leukocytes. Results from the studies showed that blood samples from these patients contained a high frequency of circulating activated platelets (CD42a⁺/CD62P⁺) when compared to samples from healthy individuals. The percentage of platelet-neutrophil, platelet-monocyte-but not platelet-lymphocyte-aggregates were also elevated in both thalassemia genotypes with marked increase in patients who had undergone splenectomy. These findings suggest that platelets adhere to neutrophils and monocytes are activated which support the clinical observation that splenectomized thalassemia patients have an increased risk of arterial or venous thrombotic manifestations.

  13. Platelets: versatile effector cells in pneumonia and sepsis

    NARCIS (Netherlands)

    de Stoppelaar, S.F.

    2015-01-01

    The role of platelets in infection and immunity is an exciting new theme, which is rapidly evolving. In this thesis we studied the involvement of platelets in the host response to pneumonia and sepsis. We made use of well established mouse models in which mice were infected with a bacterial inoculum

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

    Science.gov (United States)

    2016-10-01

    proposes to determine the efficacy of using a pathogen inactivation technique (Mirasol) coupled with a platelet additive solution (PAS) to extend the life...participation. • Subjects must have good veins for apheresis platelet collection and drawing blood samples. • Subjects of child-bearing potential (either male or

  15. Changes in platelet functional parameters and CD62 P expression ...

    African Journals Online (AJOL)

    EB

    The platelet-rich supernatant was then separated. Up to 50 µl supernatant was mixed with. CD62P monoclonal antibody (Becton-Dickinson) labeled with phycoerythrin, 20 ul aliquot was mixed and used for testing, and another 50 µl platelet-rich plasma was placed in a tube and mixed with phosphate buffer solution (PBS) ...

  16. Platelet transfusions: the science behind safety, risks and appropriate applications.

    Science.gov (United States)

    Spiess, Bruce D

    2010-03-01

    Platelets are active metabolising cells that are evolved for the tasks of haemostasis, inflammatory reactions and wound healing. When platelet products are stored in the blood bank a complex series of changes occur, leading to partial activation, up-regulation of inflammatory mediators, cellular morphology changes, loss of cell membrane lipids and micro-particle formation, as well as apoptosis. The resultant coagulation transfusion product has a number of potential expected side effects including fever, alloimmunisation, sepsis, thrombosis and transfusion-related acute lung injury. Of course, these events are occasional side effects yet they are some of the most common potential disasters of transfusion. Platelet transfusions in patients bleeding from thrombocytopaenia or severe platelet suppression will most likely benefit from a platelet transfusion. However, outcome data (controversial) have shown in some populations that platelet transfusions are associated with worse patient outcomes. Such associations may be due to the biologic changes that have occurred during storage, lack of HLA matching as well as other causes or it could be a mismatch of the platelet products to patient's needs (over-use). Platelets are administered in the surgical arena often due to 'clinical judgement', which errs on the side of, perhaps, too frequent use.

  17. Indium-111 labelled platelets: experimental and clinical studies

    International Nuclear Information System (INIS)

    Gjerloeff Schmidt, K.

    1985-10-01

    The object of the present study became to develop a method of effective and gentle isolation and 111-In labelling of human platelets, as well as to employ these platelets in human clinical studies with the object of elucidating a number of physiological and pathophysiological mechanisms and processes in which platelets take part. 111-In-oxine presents obvious advantages over 51-Cr-sodium chromate; a high labelling efficiency, and more advantageous physical properties (a half life of 68 hours (against the half life of 28 days for 51-Cr) and considerably more effective gamma emission), making external registration by means of a gamma camera possible. Considering the role played by platelets in the development of atherosclerosis and its thromboembolic complications, in the early phases of deep venous thrombosis, and in graft rejection, it is natural that attempts have been made to use 111-In-labelled platelets for scintigraphic and kinetic evaluation of thromboembolic processes. Accumulation of 111-In-labelled platelets at sites of vessel wall injury, on pulmonary emboli (presumably on deep vein thrombi as well), and on catheter material has been demonstrated. Beyond this, the number of publications concerning the use of 111-In-labelled platelets for visualization of atherosclerosis, venous thromboembolism, arterial grafts, intracardiac thrombi, aortic aneurysms, renal allograft rejection, and other situations in which platelet thromboembolism takes place, provides evidence that a tool has finally been found for the study of their nature and response to therapeutic intervention. (eg)

  18. Isoforms of purified methyltransferase from human blood platelets ...

    African Journals Online (AJOL)

    ... purification from normal human blood platelets have not been investigated, hence, the aim of this study was to purify, characterise the enzyme from human blood platelets and determine its possible role in phospholipid transmethylation. The plasma membranes were purified by velocity and sucrose gradient centrifugation ...

  19. The Role of Anticoagulation in the Measurement of Platelet Volumes.

    Science.gov (United States)

    1983-03-10

    Haematol. 25:675-689. 5. Coulter Electronics. 1978. Coulter Counter Model S-Plus Instruction Manual . Hialeah, FL. 6. Cowan, D. H., A. L. Robertson, P...platelet function. Thromb. Diath. Haemorrh., 33:63-65. 23. Zucker, M. B. and J. Borrelli . 1954. Reversible alterations in platelet morphology produced

  20. Variation of pH-measurement in platelet concentrates

    NARCIS (Netherlands)

    van der Meer, P. F.; van Zanten, A. P.; Pietersz, R. N.; Reesink, H. W.

    2001-01-01

    To measure pH in platelet concentrates, blood gas analysers with different calibration principles may be used. In this study, variances observed in pH measurements with two types of blood gas analysers were investigated. pH was measured in crystalloid solutions (platelet additive solution (PAS-II),

  1. Detection of accessory spleens with indium 111-labeled autologous platelets

    International Nuclear Information System (INIS)

    Davis, H.H. II; Varki, A.; Heaton, W.A.; Siegel, B.A.

    1980-01-01

    In two patients with recurrent immune thrombocytopenia, accessory splenic tissue was demonstrated by radionuclide imaging following administration of indium 111-labeled autologous platelets. In one of these patients, no accessory splenic tissue was seen on images obtained with technetium 99m sulfur colloid. This new technique provides a simple means for demonstrating accessory spleens and simultaneously evaluating the life-span of autologous platelets

  2. Platelet Levels and Implications For Pre-Dialysis Chronic Renal ...

    African Journals Online (AJOL)

    Platelet count is assumed to be normal in chronic renal insufficiency. However, the possible effect of loss of platelet function in chronic renal failure (CFR) in relation to occult chronic blood loss, haematuria and overall health of the patient has not been given the desired attention. The aim of this study was to determine the ...

  3. Zinc and platelet membrane microviscosity in Alzheimer's disease

    African Journals Online (AJOL)

    Outcome measures. Plasma zinc levels, platelet membrane microviscosity and cognition (MMSE and. ADAS-cog tests). Results. Oral zinc supplementation (30 mglday) did not increase plasma zinc levels significantly, but signfficantly increased platelet membrane microviscosity (P = 0.02; 6 patients). Four patients. who ...

  4. Needle-shaped and platelet growth of borax crystals

    International Nuclear Information System (INIS)

    Takoo, R.K.; Patel, B.R.; Joshi, M.S.

    1983-01-01

    Needle-shaped and platelet growth of borax crystals from solutions is reported. Results of microtopographical studies on both the varieties are discussed. It is suggested that a slow rate of evaporation favours needle growth and a faster rate is conducive to the growth of platelets. (author)

  5. Platelet rich plasma in dermatology and aesthetic medicine

    OpenAIRE

    Neerja Puri

    2015-01-01

    Platelet rich plasma is a promising therapy in dermatology and aesthetic medicine. In this article we will discuss the pros and cons of platelet rich plasma (PRP) and the usage of PRP in aesthetics. PRP is especially used for conditions like facial and neck rejuvenation, fine lines and wrinkles, abdominal striae and facial scarring.

  6. Platelet rich plasma in dermatology and aesthetic medicine

    Directory of Open Access Journals (Sweden)

    Neerja Puri

    2015-04-01

    Full Text Available Platelet rich plasma is a promising therapy in dermatology and aesthetic medicine. In this article we will discuss the pros and cons of platelet rich plasma (PRP and the usage of PRP in aesthetics. PRP is especially used for conditions like facial and neck rejuvenation, fine lines and wrinkles, abdominal striae and facial scarring.

  7. Survival curves study of platelet labelling with 51Cr

    International Nuclear Information System (INIS)

    Penas, M.E.

    1981-01-01

    Platelet kinetics and idiopathic thrombocytopenic purpura were researched in the literature. An 'in vitro' platelet labelling with 51 Cr procedure in implementation has been evaluated in human beings. Functions used for fitting considered the cases whether the curve was linear or exponential as well as the presence of hematies. (author)

  8. Platelet Immunology in China: Research and Clinical Applications.

    Science.gov (United States)

    Wu, Guoguang; Zhou, Yan; Li, Lilan; Zhong, Zhoulin; Li, Hengchong; Li, Haiyan; Yu, Mei; Shen, Weidong; Ni, Heyu

    2017-04-01

    Immunization against human platelet alloantigens (HPAs) is associated with a number of clinical complications. The detection and identification of clinically relevant platelet antibodies are important for the diagnosis and management of patients affected with immune-mediated thrombocytopenias. Human platelet alloantigen frequencies and the characteristics of antiplatelet antibodies vary widely between ethnic groups. Since 2008, the importance of platelet immunology in the field of transfusion medicine has gained greater recognition by clinical laboratories in China. Laboratories in China have established and improved methods for platelet antibody detection and HPA genotyping techniques, which are used for the diagnosis of alloimmune platelet disorders in clinic and research environments. Research has revealed the frequencies of HPA alleles in different Chinese ethnic groups and compared the differences in HPA gene frequencies between the Chinese Han and other ethnic groups of the world. Production of anti-CD36 isoantibodies is an important risk factor for immune-mediated thrombocytopenia in the Chinese population. Advances in research and clinical application of platelet immunology have significantly improved the clinical diagnosis, treatment including transfusion support, and prevention of alloimmune platelet disorders in the Chinese population. Copyright © 2017. Published by Elsevier Inc.

  9. New 'ex vivo' radioisotopic method of quantitation of platelet deposition

    International Nuclear Information System (INIS)

    Badimon, L.; Mayo Clinic, Rochester, MN; Thrombosis and Atherosclerosis Unit, Barcelona; Mayo Clinic, Rochester, MN; Fuster, V.; Chesebro, J.H.; Dewanjee, M.K.

    1983-01-01

    We have developed a sensitive and quantitative method of 'ex vivo' evaluation of platelet deposition on collagen strips, from rabbit Achilles tendon, superfused by flowing blood and applied it to four animal species, cat, rabbit, dog and pig. Autologous platelets were labeled with indium-111-tropolone, injected to the animal 24 hr before the superfusion and the number of deposited platelets was quantitated from the tendon gamma-radiation and the blood platelet count. We detected some platelet consumption with superfusion time when blood was reinfused entering the contralateral jugular vein after collagen contact but not if blood was discarded after the contact. Therefore, in order to have a more physiological animal model we decided to discard blood after superfusion of the tendon. In all species except for the cat there was a linear relationship between increase of platelet on the tendon and time of exposure to blood superfusion. The highest number of platelets deposited on the collagen was found in cats, the lowest in dogs. Ultrastructural analysis showed the platelets were deposited as aggregates after only 5 min of superfusion. (orig.)

  10. The Non-Hemostatic Aspects of Transfused Platelets

    Science.gov (United States)

    Sut, Caroline; Tariket, Sofiane; Aubron, Cécile; Aloui, Chaker; Hamzeh-Cognasse, Hind; Berthelot, Philippe; Laradi, Sandrine; Greinacher, Andreas; Garraud, Olivier; Cognasse, Fabrice

    2018-01-01

    Platelets transfusion is a safe process, but during or after the process, the recipient may experience an adverse reaction and occasionally a serious adverse reaction (SAR). In this review, we focus on the inflammatory potential of platelet components (PCs) and their involvement in SARs. Recent evidence has highlighted a central role for platelets in the host inflammatory and immune responses. Blood platelets are involved in inflammation and various other aspects of innate immunity through the release of a plethora of immunomodulatory cytokines, chemokines, and associated molecules, collectively termed biological response modifiers that behave like ligands for endothelial and leukocyte receptors and for platelets themselves. The involvement of PCs in SARs—particularly on a critically ill patient’s context—could be related, at least in part, to the inflammatory functions of platelets, acquired during storage lesions. Moreover, we focus on causal link between platelet activation and immune-mediated disorders (transfusion-associated immunomodulation, platelets, polyanions, and bacterial defense and alloimmunization). This is linked to the platelets’ propensity to be activated even in the absence of deliberate stimuli and to the occurrence of time-dependent storage lesions. PMID:29536007

  11. The Non-Hemostatic Aspects of Transfused Platelets

    Directory of Open Access Journals (Sweden)

    Caroline Sut

    2018-02-01

    Full Text Available Platelets transfusion is a safe process, but during or after the process, the recipient may experience an adverse reaction and occasionally a serious adverse reaction (SAR. In this review, we focus on the inflammatory potential of platelet components (PCs and their involvement in SARs. Recent evidence has highlighted a central role for platelets in the host inflammatory and immune responses. Blood platelets are involved in inflammation and various other aspects of innate immunity through the release of a plethora of immunomodulatory cytokines, chemokines, and associated molecules, collectively termed biological response modifiers that behave like ligands for endothelial and leukocyte receptors and for platelets themselves. The involvement of PCs in SARs—particularly on a critically ill patient’s context—could be related, at least in part, to the inflammatory functions of platelets, acquired during storage lesions. Moreover, we focus on causal link between platelet activation and immune-mediated disorders (transfusion-associated immunomodulation, platelets, polyanions, and bacterial defense and alloimmunization. This is linked to the platelets’ propensity to be activated even in the absence of deliberate stimuli and to the occurrence of time-dependent storage lesions.

  12. Significance of platelet activation in sickle cell anaemia | Ibanga ...

    African Journals Online (AJOL)

    Background: There is increasing evidence suggesting the contribution of platelets in the vaso-occlusive phenomena found in sickle cell anaemia. This study is aimed at using simple, inexpensive parameters to determine the role of platelets in the steady state and vaso-occlusive crisis state of Nigerian sickle cell anaemia ...

  13. Platelet morphological, functional and rheological properties attributable to addictions.

    Science.gov (United States)

    Zvetkova, Elissaveta; Antonova, Nadia; Ivanov, Ivan; Savov, Yonko; Gluhcheva, Yordanka

    2010-01-01

    Hemorheological abnormalities such as elevated whole blood viscosity, plasma viscosity, erythrocyte deformability and platelet aggregation, hematocrit and fibrinogen levels, are frequently examined as diagnostic tool and prognostic relevance in socially important hemorheological disorders. Distinct biological - morphological and functional platelet alterations, have been described in different addictions (heroin-, cocaine-, nicotine-, alcohol-, etc.). Chronic addictions could cause biochemical and conformational changes in platelets and their membranes, thus modulating platelet receptor expression, morphology (anisocytosis, giant platelets) and activation (alpha-granule release), platelet aggregation and hemorheological properties. Some of these alterations in chronic addicts - documented at cellular- and molecular level, could be easily used as a precise diagnostic tool with regard to thromboembolic complications and microcirulation injuries attributable to addictions. The present review focuses on some changes in platelet morphological, functional and rheological properties induced by chronic opiate/opioid abuse. Hypothesis is accumulated that free fatty acids (FFAs) and especially oleic acid (OA) could cause positive molecular and conformational changes in platelets of addicts with hemorheological disorders.

  14. Platelet function, anthropometric and metabolic variables in Nigerian ...

    African Journals Online (AJOL)

    Platelet function, anthropometric and metabolic variables in Nigerian Type 2 Diabetic patients. ... (BSA) were assessed as indices of anthropometry, fasting blood sugar (FBS), plasma cholesterol and triglycerides (TAG) were determined using standard method and platelet aggregation test was done on the whole blood.

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

    Directory of Open Access Journals (Sweden)

    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.

  16. Diagnosis of labelled platelets scintigraphy in patients with cardiovascular diseases

    International Nuclear Information System (INIS)

    Laforte, C. de; Ambrosi, P.; Bernard, P.J.

    1991-01-01

    Scintigraphy with [111 In] oxine labelled platelets is a powerful tool to detect platelet deposits in heart and vessels. This quantitative and functional imaging method needs a labeling procedure which completely preserves the properties of the platelets and allows the concept of hematologically active clot. Four main groups of patients are able to profit by this method. 1) Patients with intra-cardiac thrombi detected by 2D-echography. Platelet scintigraphy specified the hematologically active pattern of the clot and allows the follow-up of pharmacological therapy. 2) Patients with lower limb ischemia, mainly in the case of blue toe syndrome. The aortic or iliac seat of the lesions, their unique or plurifocal patterns are better localized with platelet scintigraphy than other imaging methods. 3) Patients with transient cerebro-vascular accidents. A focal deposit of platelets on carotid arteries is a strong argument for surgery. As in the cases of intra-cardiac thrombi, the method allows the follow-up of pharmacological therapy. 4) Patients with arterial grafts. Platelet scintigraphy provides the mean to follow the thrombogenic behaviour of the material and the preventive effects of anti-thrombic drugs. Platelets labelled with 111 Indium provide the means for sensitive and specific detection of hematologically active clots in cardiac and arterial pathology [fr

  17. Functional aspects of blood platelets in irradiated burros

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, M.D.

    1977-02-01

    In irradiated burros (Equus asinus), a delayed clinical syndrome characterized by a depletion of megakarocytes and platelets has been observed. To clarify the cause of this syndrome, the functional abilities of platelets in 7 irradiated and 3 control burros were studied in vitro. The irradiated burros were survivors (> 18 years) of total-body exposures to near-lethal doses of ..gamma..-radiation. Burro platelet aggregability induced with adenosine diphosphate and thrombin, and with a complex stimulator from burro aortas, was determined by means of a self-calibrating aggregometer. Data indicated that the aggregation responsiveness to adenosine diphosphate and thrombin of platelets from surviving irradiated and unirradiated burros is not defective. An extractible collagen-like stimulator of platelet aggregation was discovered in the aorta of a burro that had survived > 24 years after exposure to a total-body dose of 545 roentgens (R) of tantalum-182 ..gamma..-radiation. The platelet-aggregating ability of this stimulator from the vessel wall of the irradiated burro was nearly fourfold greater than that from the aorta of an unirradiated control. Perhaps a delayed radiation effect could be the cause of this vascular agent's high platelet-aggregating ability and could lead to a clinical syndrome marked by depletion of megakaryocytes and platelets.

  18. Identification of calcium-binding proteins in human platelets

    International Nuclear Information System (INIS)

    Brumley, L.M.; Wallace, R.W.

    1986-01-01

    In human platelets, intracellular Ca 2+ is a second messenger for platelet agonists. Two targets for the Ca 2+ signal are calmodulin and the C-,inase; however, other Ca 2+ -binding proteins may also play a role in platelet function. The Western blotting technique of Maruyama et al., which utilizes 45 Ca 2+ to detect Ca 2+ -binding proteins, has been used to identify numerous platelet Ca 2+ -binding proteins ranging in molecular weight from 165K to 15K. The greatest quantity of 45 Ca 2+ was bound to a 165 kilodalton protein which has been identified as thrombospondin based upon its release from thrombin-stimulated platelets and its comigration on SDS gels with purified thrombospondin. Two other major sites for 45 Ca 2+ -binding correspond to proteins of 120K and 108K which are present only in the platelet particulate fraction; they have been identified as glycoproteins IIb and IIIa based upon their labeling by 125 I-concanavalin A. Two proteins with molecular weights of 20K and 15K bound much less 45 Ca 2+ and correspond on SDS gels to calmodulin and subunit B of the calmodulin-dependent phosphatase. A number of other, yet to be identified, Ca 2+ -binding proteins were also detected. These data indicate that human platelets contain numerous Ca 2+ -binding proteins and that Western blotting techniques utilizing 45 Ca 2+ may be useful as an assay system in future attempts to purify platelet Ca 2+ -binding proteins

  19. Effect of varying concentrations of orally ingested glucose on platelet ...

    African Journals Online (AJOL)

    The physiologic basis of bleeding is a function of normal platelets and coagulation factors. This study is aimed at ascertaining the effect of varying concentrations of orally ingested glucose on platelet count and hemoglobin concentration during menstruation. Forty menstruating students between the ages of 18 and 25 from ...

  20. The haemostatic effect of 51Cr-labelled blood platelets

    International Nuclear Information System (INIS)

    Bjoernson, J.; Aursnes, I.

    1977-01-01

    The haemostatic effect of 51 Cr-labelled platelets was studied in 5 rabbits made thrombocytopenic (35,000/μl blood) by whole body ionizing irradiation. Bleeding times were recorded after standardized cuts on the inner side of the rabbit's ear, a method with an acceptable reproducibility. The animals were then each transfused with concentrates of labelled pletelets from 2 healthy donor rabbits. This increased the platelet counts to about 2 x 10 5 /μl blood. Bleeding time values were markably prolonged before transfusion and became normalized when tested 1 and 4 h after transfusion. In 3 control experiments, where unlabelled platelet rich plasma was transfused to thrombocytopenic recipients, a similar shortening of the bleeding time was observed. It is concluded that 51 Cr-labelled platelets retain haemostatic ability comparable to non-labelled platelets, when circulating in a recipient animal. (author)

  1. Low platelet monoamine oxidase activity in pathological gambling

    International Nuclear Information System (INIS)

    Carrasco, J.L.; Saiz-Ruiz, J.; Hollander, E.; Cesar, J.; Lopez-Ibor, J.J. Jr.

    1994-01-01

    Decreased platelet monoamine oxidase (MAO) activity has been reported in association with sensation-seeking personality type and in some mental disorders associated with a lack of impulse control. Pathological gambling itself has been related with both sensation-seeking and reduced impulse control. Platelet MAO activity was investigated in 15 DSM-III-R pathological gamblers from our outpatient clinic. Gamblers had a significantly lower platelet MAO activity than a group of 25 healthy controls. The range of MAO levels in gamblers was also significantly shorter than in controls. In controls, platelet MAO levels showed the previously described negative correlations with sensation-seeking scores but not in gamblers. The findings are consistent with previous studies showing an association of low platelet MAO activity with impulse control disorders and raise some interesting therapeutic alternatives for pathological gambling. (au) (40 refs.)

  2. Resistance of platelet proteins to effects of ionizing radiation

    International Nuclear Information System (INIS)

    Prodouz, K.N.; Habraken, J.W.; Moroff, G.

    1990-01-01

    Gamma irradiation of blood components prevents lymphocyte-induced graft-versus-host disease after transfusion in immunocompromised individuals. In this report we demonstrate the resistance of blood platelet proteins to gamma radiation-induced protein cleavage and aggregate formation when platelet concentrates were treated with a dose of 5000 rad. Results of one- and two-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis of total platelet protein and cytoskeletal protein preparations indicate that platelet proteins are neither cleaved nor cross-linked under these conditions of irradiation. These results support those of a previous study that documented the lack of any adverse effect of 5000 rad gamma radiation on in vitro platelet properties

  3. Low platelet monoamine oxidase activity in pathological gambling

    Energy Technology Data Exchange (ETDEWEB)

    Carrasco, J.L. [Department of Psychiatry, Centro de Salud Mental, Parla Madrid (Spain); Saiz-Ruiz, J. [Department of Psychiatry and Haematology, Hospital Ramon y Cajal, Madrid (Spain); Hollander, E. [Department of Psychiatry, Mount Sinai School of Medicine, Queens Hospital Center, New York (United States); Cesar, J. [Department of Haematology, Hospital Ramon y Cajal, Madrid (Spain); Lopez-Ibor, J.J. Jr. [Department of Psychiatry, Hospital San Carlos, Complutense University, Madrid (Spain)

    1994-12-01

    Decreased platelet monoamine oxidase (MAO) activity has been reported in association with sensation-seeking personality type and in some mental disorders associated with a lack of impulse control. Pathological gambling itself has been related with both sensation-seeking and reduced impulse control. Platelet MAO activity was investigated in 15 DSM-III-R pathological gamblers from our outpatient clinic. Gamblers had a significantly lower platelet MAO activity than a group of 25 healthy controls. The range of MAO levels in gamblers was also significantly shorter than in controls. In controls, platelet MAO levels showed the previously described negative correlations with sensation-seeking scores but not in gamblers. The findings are consistent with previous studies showing an association of low platelet MAO activity with impulse control disorders and raise some interesting therapeutic alternatives for pathological gambling. (au) (40 refs.).

  4. Platelet content of nitric oxide synthase 3 phosphorylated at Serine 1177 is associated with the functional response of platelets to aspirin.

    Directory of Open Access Journals (Sweden)

    Javier Modrego

    Full Text Available OBJECTIVE: To analyse if platelet responsiveness to aspirin (ASA may be associated with a different ability of platelets to generate nitric oxide (NO. PATIENTS/METHODS: Platelets were obtained from 50 patients with stable coronary ischemia and were divided into ASA-sensitive (n = 26 and ASA-resistant (n = 24 using a platelet functionality test (PFA-100. RESULTS: ASA-sensitive platelets tended to release more NO (determined as nitrite + nitrate than ASA-resistant platelets but it did not reach statistical significance. Protein expression of nitric oxide synthase 3 (NOS3 was higher in ASA-sensitive than in ASA-resistant platelets but there were no differences in the platelet expression of nitric oxide synthase 2 (NOS2 isoform. The highest NOS3 expression in ASA-sensitive platelets was independent of the presence of T-to-C mutation at nucleotide position -786 (T(-786 → C in the NOS3-coding gene. However, platelet content of phosphorylated NOS3 at Serine (Ser(1177, an active form of NOS3, was higher in ASA-sensitive than in ASA-resistant platelets. The level of platelet NOS3 Ser(1177 phosphorylation was positively associated with the closure time in the PFA-100 test. In vitro, collagen failed to stimulate the aggregation of ASA-sensitive platelets, determined by lumiaggregometry, and it was associated with a significant increase (p = 0.018 of NOS3 phosphorylation at Ser(1177. On the contrary, collagen stimulated the aggregation of ASA-resistant platelets but did not significantly modify the platelet content of phosphorylated NOS3 Ser(1177. During collagen stimulation the release of NO from ASA-sensitive platelets was significantly enhanced but it was not modified in ASA-resistant platelets. CONCLUSIONS: Functional platelet responsiveness to ASA was associated with the platelet content of phosphorylated NOS3 at Ser(1177.

  5. Platelets stimulate fibroblast-mediated contraction of collagen gels

    Directory of Open Access Journals (Sweden)

    Lundahl Joachim

    2003-10-01

    Full Text Available Abstract Background Platelets are thought to play a role in a variety of inflammatory conditions in the lung, some of which may lead to fibrosis. In the current study we tested the hypothesis that whole platelets and platelet lysate can mediate remodelling of extracellular matrix in vitro by affecting fibroblast-mediated contraction of a collagen gel. We also sought to determine to what extent platelet-derived growth factor (PDGF and transforming growth factor-β (TGF-β contribute to this effect. Methods Washed platelets, isolated from healthy blood donors, and platelet lysate (freezing and thawing, were cast together with human lung fibroblasts in three-dimensional collagen gels. The gels were then released and cultured for four days. PDGF and TGF-β1 concentrations were measured in culture supernatants by ELISA. Results Both platelets and platelet lysate augmented fibroblast-mediated gel contraction in a time and concentration dependent manner (19.9% ± 0.1 (mean ± SEM of initial area vs. 48.0% ± 0.4 at 48 hours; P 1 and PDGF-AA/AB were released in co-culture. PDGF-AA/AB had a maximum release at 24 hours whereas TGF-β1 release increased with longer culture periods. Neutralising antibodies to these mediators partially inhibited platelet-induced gel contraction. Conclusion We conclude that platelets may promote remodelling of extracellular matrix in vitro and that PDGF and TGF-β partially mediate this effect, also indicating a role for other mediators. The findings may be an important mechanism in regulating repair processes after injury.

  6. Platelets Toll-like receptor-4 in Crohns disease.

    Science.gov (United States)

    Schmid, Werner; Novacek, Gottfried; Vogelsang, Harald; Papay, Pavol; Primas, Christian; Eser, Alexander; Panzer, Simon

    2017-02-01

    Platelets are activated in Crohn's disease (CD) and interplay with leukocytes. Engagement of Toll-like receptor-4 (TLR-4), which is expressed in human platelets, may be involved in crosstalks between platelets and leukocytes leading to their mutual activation for host defense. Human neutrophil peptides (HNPs), lipoprotein binding peptides, and sCD14 were determined by enzyme-linked immunosorbent assays in 42 patients with active CD, in 43 patients with CD in remission, and in 30 healthy individuals. Neutrophil-platelet aggregates and binding of the TLR-4 monoclonal antibody to platelets were determined by flow cytometry. Levels of HNPs were higher in patients with CD than in controls (P = 0.0003 vs. active CD and P = 0.01 vs. CD in remission). Likewise, neutrophils with adhering platelets were higher in patients with active CD than in controls (P = 0.004). Binding of the TLR-4 antibody in patients with active CD was similar to that in controls, while patients in remission had significantly higher binding capacities (P = 0.59 and P = 0.003). Incubation of plasma from patients with active disease or patients in remission with platelets from healthy controls confirmed lower binding of the TLR-4 antibody in the presence of plasma from active diseased patients compared to controls (P = 0.039), possibly due to high levels of lipopolysaccharides, as suggested by high levels of sCD14 and lipoprotein binding protein. Our study indicates involvement of platelet TLR-4 in enhancing the secretion of antimicrobial peptides from neutrophils. While platelet aggregation can be due to a variety of mechanisms in inflammatory disease, the mutual activation of platelets and neutrophils may augment host defense. © 2016 Stichting European Society for Clinical Investigation Journal Foundation.

  7. Functional platelet defects in children with severe chronic ITP as tested with 2 novel assays applicable for low platelet counts

    NARCIS (Netherlands)

    van Bladel, Esther R.; Laarhoven, Annemieke G.; van der Heijden, Laila B.; Heitink-Pollé, Katja M.; Porcelijn, Leendert; van der Schoot, C. Ellen; de Haas, Masja; Roest, Mark; Vidarsson, Gestur; de Groot, Philip G.; Bruin, Marrie C. A.

    2014-01-01

    Immune thrombocytopenia (ITP) is an autoimmune disease with a complex heterogeneous pathogenesis and a bleeding phenotype that is not necessarily correlated to platelet count. In this study, the platelet function was assessed in a well-defined cohort of 33 pediatric chronic ITP patients. Because

  8. Kinetics and biodistribution of In-111 platelets in patients with bone marrow transplants, refractory to platelet transfusions

    International Nuclear Information System (INIS)

    Civelek, C.; Braine, H.; Scheffel, U.; Drew, H.; Koester, A.; LaFrance, N.; Kasecamp, W.; Wagner, H. Jr.

    1984-01-01

    The kinetics and biodistribution of HLA identical In-111 labeled platelets was studied in 10 leukemic patients with bone marrow transplants refractory to HLA matched platelet transfusions. Platelet survival time was short (x-bar +- SEM =1.64 +- 0.83 days). The mean recovery (extrapolated to zero time) was 29.9%, ranging from 14.2 to 63.0%. The deposition of the In-111 platelets in the liver and spleen was quantified by the geometric mean method using anterior and posterior imaging. In 3 patients liver uptake was significantly increased. The highest hepatic accumulation of In-111 occurred 2 hrs after injection (x-bar=76 +- 6% dose (SEM); at 48 hrs 62% of the dose remained in the liver. In 7 patients the spleen was the organ with the highest labeled platelet deposition. The splenic uptake of In-111 platelets in this group correlated with the spleen size (r=+0.95). At 30 min after injection 75+-6% of the dose was found in the spleen. Splenic activity decreased to 62% after 48 hrs. At the same time, In-111 liver accumulation increased from 14 to 31%. This finding suggests that In-111 may be released from the spleen and subsequently sequestered by the liver. Two patients with high splenic uptake underwent splenectomy after the In-111 platelet study. Both benefited from splenectomy in terms of platelet survival after transfusion

  9. Can platelet count and mean platelet volume during the first trimester of pregnancy predict preterm premature rupture of membranes?

    Science.gov (United States)

    Ekin, Atalay; Gezer, Cenk; Kulhan, Gözde; Avcı, Muhittin Eftal; Taner, Cuneyt Eftal

    2015-01-01

    The aim of our study was to evaluate the values of platelet count and mean platelet volume (MPV) obtained from maternal serum during the first trimester to predict subsequent preterm premature rupture of membranes (PPROM). The records of 318 women with PPROM and 384 healthy controls in a single center between 2009 and 2013 were retrospectively evaluated. Platelet count and MPV values between 7 and 14 weeks of gestation were compared. Receiver-operator curve analysis was performed to identify the optimal platelet count and MPV cut-off levels predicting PPROM. Compared with controls, women with PPROM had significantly increased levels of platelet count and significantly decreased levels of MPV in the first trimester (P receiver-operator curve was 0.642 for MPV and 0.579 for platelet count. The cut-off values of MPV ≤ 8.6 fL and platelet count ≥216 × 10(3) /μL predicted PPROM with a sensitivity of 58% and 65% and specificity of 62% and 44%, respectively. MPV can be used as a more efficient predictor for an early diagnosis of PPROM than platelet count. However, further research combining other markers is needed to increase the efficiency of prediction. © 2014 The Authors. Journal of Obstetrics and Gynaecology Research © 2014 Japan Society of Obstetrics and Gynecology.

  10. Platelet-Derived Microvesicles in Cardiovascular Diseases

    Directory of Open Access Journals (Sweden)

    Maria T. K. Zaldivia

    2017-11-01

    Full Text Available Microvesicles (MVs circulating in the blood are small vesicles (100–1,000 nm in diameter derived from membrane blebs of cells such as activated platelets, endothelial cells, and leukocytes. A growing body of evidence now supports the concept that platelet-derived microvesicles (PMVs, the most abundant MVs in the circulation, are important regulators of hemostasis, inflammation, and angiogenesis. Compared with healthy individuals, a large increase of circulating PMVs has been observed, particularly in patients with cardiovascular diseases. As observed in MVs from other parent cells, PMVs exert their biological effects in multiple ways, such as triggering various intercellular signaling cascades and by participating in transcellular communication by the transfer of their “cargo” of cytoplasmic components and surface receptors to other cell types. This review describes our current understanding of the potential role of PMVs in mediating hemostasis, inflammation, and angiogenesis and their consequences on the pathogenesis of cardiovascular diseases, such as atherosclerosis, myocardial infarction, and venous thrombosis. Furthermore, new developments of the therapeutic potential of PMVs for the treatment of cardiovascular diseases will be discussed.

  11. Plasma rico en plaquetas Platelet -rich plasma

    Directory of Open Access Journals (Sweden)

    J. González Lagunas

    2006-04-01

    Full Text Available El Plasma Rico en Plaquetas es una suspensión concentrada de la sangre centrifugada que contiene elevadas concentraciones de trombocitos. Durante los últimos años, este producto ha aparecido de forma repetida en publicaciones científicas y en medios de comunicación generales como un producto que por sus características induce la curación y regeneración de los tejidos. La premisa de su uso es que las elevadas concentraciones de plaquetas en el PRP, liberan cantidades significativas de factores de crecimiento. En este artículo se van a recoger las evidencias científicas que se han presentado en la literatura médica con respecto al PRP y a la curación ósea, así como las diferentes aplicaciones clínicas que se han sugerido.Platelet-rich plasma is a by-product of centrifuged whole blood that contains high levels of thrombocytes. In the last decade, scientific and media interest has been generated by this product that apparently has the capacity of inducing and promoting tissue healing and regeneration. The premise of its use is that the large number of platelets in PRP release significant amounts of growth factors. In this paper, a critical review of the medical literature regarding PRP and bone healing will be presented. Also, the suggested clinical applications of the product will be addressed.

  12. The effect of centrifugation speed and time on pre-analytical platelet activation.

    Science.gov (United States)

    Söderström, Anna C; Nybo, Mads; Nielsen, Christian; Vinholt, Pernille J

    2016-12-01

    The results of laboratory analyses are affected by pre-analytical variables, and in particular can platelets be activated by shear handling stress and secrete granular substances. We therefore evaluated the effect of centrifugation speed and time on pre-analytical platelet activation. Citrate- and EDTA-anticoagulated blood from healthy volunteers were centrifuged at 80-10,000 g for 5-15 min to prepare plasma and platelet-rich plasma. Pre-analytical platelet activation was assessed by flow cytometric measurement of platelet P-selectin (CD62p) expression. Blood cell counts, mean platelet volume (MPV), immature platelet fraction (IPF), and platelet distribution width (PDW) were measured. Platelet aggregation in platelet-rich plasma induced by arachidonic acid (AA), ADP or thrombin receptor activator peptide-6 (TRAP) was tested by 96-well aggregometry. The median percentage of platelets expressing P-selectin in citrate- and EDTA-plasma centrifuged at 2000 g for 10 min were 43% [interquartile range (IQR), 38%-53%] and 56% (IQR, 31%-78%), respectively (p=0.82). Platelet-rich plasma prepared at 100-250 g for 10 min had significantly lower platelet P-selectin expression (11%-15%), pcentrifuged. In platelet-rich plasma, increasing centrifugation speed significantly increased platelet yield but decreased contamination from other blood cells, platelet composition was altered as platelet parameters (MPV, IPF, and PDW) was lowered. Platelet aggregation was not affected by the centrifugation speed platelet-rich plasma was prepared. Proportional to centrifugation speed, platelets in plasma and platelet-rich plasma were activated with centrifugation speed, cell content and composition changed while platelet aggregation was unaltered.

  13. Investigation of neutrophil-to-lymphocyte ratio, platelet-to-lymphocyte ratio and mean platelet volume in patients with tinnitus.

    Science.gov (United States)

    Ulusoy, B; Bozdemir, K; Akyol, M; Mişe, H I; Kutluhan, A; Korkmaz, M H

    2018-02-01

    This study aimed to evaluate patients with tinnitus in terms of mean platelet volume and platelet distribution width, and to explore neutrophil-to-lymphocyte ratio and platelet-to-lymphocyte ratio, recently reported in the literature as being possible inflammation markers. This study comprised 64 tinnitus patients and 64 age-matched healthy controls. Statistical significance level was accepted as p < 0.05. Mean platelet volume (t = 3.245, p = 0.002) and platelet distribution width (Z = 3.945, p < 0.001) were significantly higher in the patient group than the control group. The results suggest that a prothrombotic condition might play a role in the pathophysiology of tinnitus.

  14. Assessment of canine autologous platelet-rich plasma produced with a commercial centrifugation and platelet recovery kit.

    Science.gov (United States)

    Frye, Chris W; Enders, Andrew; Brooks, Marjory B; Struble, Angela M; Wakshlag, Joseph J

    2016-01-01

    To characterize the cellular composition (platelets, erythrocytes, and leukocytes) and confirm reproducibility of platelet enrichment, as well as determine the platelet activation status in the final product of a commercial platelet-rich plasma kit using canine blood. Venous blood from 20 sedated client-owned dogs was used to prepare platelet-rich plasma (PRP) from a commercial kit. Complete blood counts were performed to determine erythrocyte, leukocyte, and platelet numbers in both whole blood (WB) and resultant PRP. The WB and PRP samples from jugular (fast collection) and cephalic (slow collection) venipuncture were also compared. P-selectin externalization was measured in WB and PRP samples from 15 of 20 dogs. This commercial kit produced an average percent recovery in platelets of 64.7 ± 17.4; erythrocytes of 3.7 ± 0.8, and leukocytes of 31.6 ± 10.0. Neutrophil, monocyte, and lymphocyte percent recovery was 19.6 ± 7.2, 44.89 ± 19.8, and 57.5 ± 10.6, respectively. The recovery of platelets from jugular venipuncture (59.7 ± 13.6%) was lower than from cephalic recovery (68.8 ± 19.1%). The mean percent P-Selectin externalization for WB, PRP, and PRP with thrombin was 25.5 ± 30.9, 4.5 ± 6.4, and 90.6 ± 4.4 respectively. Cellular reproducibility of this kit was confirmed and platelets were concentrated within autologous serum. Additionally, measurements of P-selectin externalization showed that platelets are inactive in PRP unless stimulated to degranulate.

  15. Microparticle counts in platelet-rich and platelet-free plasma, effect of centrifugation and sample-processing protocols.

    Science.gov (United States)

    Chandler, Wayne L

    2013-03-01

    This study provides the first estimates of microparticle numbers in platelet-rich plasma (PRP) from normal individuals, closer to in-vivo levels, using higher-resolution flow cytometry. We measured platelet (CD41+) and annexin V+ microparticles in fresh and frozen aliquots of PRP, platelet-poor plasma, platelet-free plasma (PFP), and microparticles isolated by high-speed centrifugation. PRP from healthy individuals contained 730,000/μl total microparticles based on light-scattering measurements. A median of 27,000/μl microparticles in PRP were of platelet origin and 120,000/μl annexin V+, and of these, 24,000/μl were dual-positive procoagulant platelet microparticles. Double centrifugation of PRP removed 99% of platelets, but also 80% of annexin V+ CD41+, 93% of annexin V+ CD41-, and 58% of annexin V- CD41+ microparticles. Loss of microparticles with centrifugation varied from individual to individual. Microparticle counts after isolation by centrifugation and double washing were not significantly different than counts in the original PFP sample, but lower than in PRP. Freeze-thawing of PFP had no effect on platelet microparticle counts, but slightly increased annexin V+, CD41- counts. Freeze-thawing of isolated washed microparticles resulted in a 30-50% increase in annexin V+ microparticles. PRP contains large numbers of cellular microparticles, including platelet and annexin V+ microparticles, which are lost to varying degrees when PRP is double centrifuged to remove platelets. Microparticles remaining in PFP can be recovered by high-speed centrifugation without loss compared to the original PFP sample. Freeze-thawing has variable effects on microparticle counts depending on the sample preparation used.

  16. Detection and identification of platelet antibodies using a sensitive multiplex assay system-platelet antibody bead array.

    Science.gov (United States)

    Metzner, Krista; Bauer, Julie; Ponzi, Heather; Ujcich, Allison; Curtis, Brian R

    2017-07-01

    Tests for platelet-specific antibodies are important in the diagnosis of immune platelet disorders. Monoclonal antibody glycoprotein capture assays have been the gold standards in platelet antibody detection for almost 30 years. However, such assays are complex and cumbersome to perform, which limits their routine use. We report the performance of a newly developed, easy to perform platelet antibody bead array (PABA) for the detection of platelet-specific antibodies. PABA is the equivalent of the monoclonal antigen capture enzyme-linked immunosorbent assay (ELISA) (MACE) on a bead and instead with fluorescent detection of immunoglobulin (Ig)G platelet antibodies by Luminex. Antibodies against platelet glycoproteins (GP) GPIIb/IIIa, GPIb/IX, GPIa/IIa, GPIV, and class I human leukocyte antigen (HLA) could be detected in a patient's serum simultaneously in a single well of a microplate. Results from 80 patient samples and 20 normal donor samples were compared using PABA, MACE, and a commercial ELISA kit. PABA detected all antibodies, with specificity for human platelet antigens (HPAs) HPA-1a, HPA-1b, HPA-2a, HPA-2b, HPA-3a, HPA-3b, HPA-4a, HPA-4b, HPA-5a, HPA-5b, HPA-15b, and HLA. Overall, compared with MACE, the sensitivity and specificity of PABA were 99% and 97%, respectively, and both were significantly better than those of the commercial ELISA. PABA had greater analytic sensitivity than MACE for HPA-1a, HPA-3a, and HPA-5b antibodies. In addition, PABA detected HPA-5b and HPA-3b antibodies that were missed by MACE. The overall false-positive rate of PABA compared with MACE was 2.7%. The PABA is a rapid, highly sensitive and specific, multiplex bead-based assay for detecting human platelet antibodies. Such a simple yet high-throughput platform will facilitate practical, routine testing for the identification of platelet-specific antibodies. © 2017 AABB.

  17. Incidence of platelet dysfunction by thromboelastography-platelet mapping in children supported with ECMO: A Pilot Retrospective Study.

    Directory of Open Access Journals (Sweden)

    Arun eSaini

    2016-01-01

    Full Text Available Background: Bleeding complications are common and decrease the odds of survival in children supported with extracorporeal membrane oxygenation (ECMO. The role of platelet dysfunction on ECMO-induced coagulopathy and resultant bleeding complications is not well understood. The primary objective of this pilot study was to determine the incidence and magnitude of platelet dysfunction according to thromboelastography (TEG®-platelet mapping (PM testing. Methods: Retrospective chart review of children <18 years old who required ECMO at a tertiary level hospital. We collected TEG®-PM and conventional coagulation tests data. We also collected demographic, medications, blood products administered, and clinical outcome data. We defined severe platelet dysfunction as less than 50 % aggregation in response to an agonist. Results: We identified 24 out of 46 children on ECMO, who had TEG®-PM performed during the study period. We found the incidence of severe bleeding was 42%, and mortality was 54% in our study cohort. In all samples measured, severe qualitative platelet dysfunction was more common for adenosine diphosphate (ADP-mediated aggregation (92% compared to arachidonic acid (AA-mediated aggregation (75%, (p=0.001. Also, ADP-mediated percent of platelet aggregation was significant lower than AA-mediated platelet aggregation (15% [IQR 2.8-48] vs 49% [IQR 22-82.5], p<0.001. There was no difference in kaolin-activated heparinase TEG® parameters between the bleeding group and the non-bleeding group. Only absolute platelet count and TEG®-PM had increased predictive value on receiver operating characteristics analyses for severe bleeding and mortality compared to ACT. Conclusions: We found frequent and severe qualitative platelet dysfunction on TEG®-PM testing in children on ECMO. Larger studies are needed to determine if the assessment of qualitative platelet function by TEG®-PM can improve prediction of bleeding complications for children on ECMO.

  18. The use of indium-111 platelet scintigraphy in man: comparisons with in vitro tests and in vivo platelet function--a five year experience

    International Nuclear Information System (INIS)

    Ezikowitz, M.D.; Ferri, P.; Pope, C.; Smith, E.O.; Snyder, E.L.

    1985-01-01

    In this paper, the authors present data collected from 540 patients between July 1978 and July 1983. They discuss briefly the method they employed for labeling platelets, emphasizing in vivo and in vitro markers of platelet function used for quality control of platelet preparation. They discuss the application of their technique for identification of mural left ventrical trombi, and review the disparity between in vivo and in vitro tests of platelet function. Then they deal with diagnosis of subacute bacterial endocarditis, deep veonus thrombosis, coronary trombi, left arterial masses, and the use of tomographic imaging. Finally they report changes in platelet function in stored platelets from normal volunteers

  19. Modified method for labeling human platelets with indium-111 oxine using albumin density-gradient separation

    International Nuclear Information System (INIS)

    Bunting, R.W.; Callahan, R.J.; Finkelstein, S.; Lees, R.S.; Strauss, H.W.

    1982-01-01

    When labeling platelets with indium-111 oxine, albumin density-gradient separation minimizes the time spent to resuspend those platelets that have been centrifuged against a hard surface. Labeling efficiency or platelet viability, as measured by platelet survival or aggregation with adenosine diphosphate, are not adversely affected

  20. The sensitivity of tests to detect in vivo platelet activation induced by ...

    African Journals Online (AJOL)

    No influence on the results of the platelet function tests was found. Tile only test capable of detecting limited injury to the endothelium was the measurement of plasma PF4: The mean platelet life-span (MPLS) shortened, mean platelet density decreased, the circulating platelet aggregate ratio decreased, and plasma levels ...

  1. Iodine-125 metaraminol: A new platelet specific labeling agent

    International Nuclear Information System (INIS)

    Ohmomo, Y.; Yokoyama, A.; Kawaii, K.; Horiuchi, K.; Saji, H.; Torizuka, K.

    1984-01-01

    In the search for a platelet specific labeling agent, Metaraminol (MA), which is a sympatomimetic amine used for the treatment of hypotension, cardiogenic shock and well recognized as a drug actively incorporated and accumulated in platelet, attracted the authors' attention. Using the classical chloramine-T iodination method, a high labeling efficiency near 98%, reaching a specific activity up to about 1000 Ci/mmole was obtained. Upon the harvest of platelet, only as platelet rich plasma (PRP), the labeling with this radiopharmaceutical was easily performed by incubation at 37 0 C for 10 min. Labeling efficiency as high as 63.0 +- 3.1% at 24 x 10/sup 8/ cells/ml was obtained. In in-vitro studies, the unaltered state of I-125 MA labeled platelet, with their cellular functions fully retained was demonstrated. Pharmacological study indicated a specific incorporation of I-125 MA by active transport system similar to that of 5-HT, along with passive diffusion. Then the in-vivo study carried out in rabbits with induced thrombi on the femoral artery, showed rather rapid disappearance of the I-125 MA labeled autologous platelet radioactivity, from circulating blood reaching as high thrombus-to-blood activity ratio as 19.8+-4.3 within 30 min post-administration. This new platelet labeling agent, I-125 MA, has many advantages over the use of IN-111 oxine and holds considerable promise for thrombus imaging with single photon emission CT upon the availability of I-123 MA

  2. Is automated platelet counting still a problem in thrombocytopenic blood?

    Directory of Open Access Journals (Sweden)

    Raimundo Antônio Gomes Oliveira

    Full Text Available CONTEXT: Reliable platelet counting is crucial for indicating prophylactic platelet transfusion in thrombocytopenic patients. OBJECTIVE: To evaluate the precision and accuracy of platelet counting for thrombocytopenic patients, using four different automated counters in comparison with the Brecher & Cronkite reference method recommended by the International Committee for Standardization in Hematology (ICSH. TYPE OF STUDY: Automated platelet counting assessment in thrombocytopenic patients. SETTING: Hematology Laboratory, Hospital do Servidor Público Estadual de São Paulo, and the Hematology Division of Instituto Adolfo Lutz, São Paulo, SP, Brazil. MAIN MEASUREMENTS: Brecher & Cronkite reference method and four different automated platelet counters. PARTICIPANTS: 43 thrombocytopenic patients with platelet counts of less than 30,000/µl RESULTS: The ADVIA-120 (Bayer, Coulter STKS, H1 System (Technicom-Bayer and Coulter T-890 automatic instruments presented great precision and accuracy in relation to laboratory thrombocytopenic samples obtained by diluting blood from normal donors. However, when thrombocytopenic patients were investigated, all the counters except ADVIA (which is based on volume and refraction index showed low accuracy when compared to the Brecher & Cronkite reference method (ICSH. The ADVIA counter showed high correlation (r = 0.947. However, all counters showed flags in thrombocytopenic samples. CONCLUSION: The Brecher & Cronkite reference method should always be indicated in thrombocytopenic patients for platelet counts below 30,000 plt /µl obtained in one dimensional counters.

  3. Microfluidic isolation of platelet-covered circulating tumor cells.

    Science.gov (United States)

    Jiang, Xiaocheng; Wong, Keith H K; Khankhel, Aimal H; Zeinali, Mahnaz; Reategui, Eduardo; Phillips, Matthew J; Luo, Xi; Aceto, Nicola; Fachin, Fabio; Hoang, Anh N; Kim, Wooseok; Jensen, Annie E; Sequist, Lecia V; Maheswaran, Shyamala; Haber, Daniel A; Stott, Shannon L; Toner, Mehmet

    2017-10-11

    The interplay between platelets and tumor cells is known to play important roles in metastasis by enhancing tumor cell survival, tumor-vascular interactions, and escape from immune surveillance. However, platelet-covered circulating tumor cells (CTC) are extremely difficult to isolate due to masking or downregulation of surface epitopes. Here we describe a microfluidic platform that takes advantage of the satellite platelets on the surface of these "stealth" CTCs as a ubiquitous surface marker for isolation. Compared to conventional CTC enrichment techniques which rely on known surface markers expressed by tumor cells, platelet-targeted isolation is generally applicable to CTCs of both epithelial and mesenchymal phenotypes. Our approach first depletes unbound, free platelets by means of hydrodynamic size-based sorting, followed by immunoaffinity-based capture of platelet-covered CTCs using a herringbone micromixing device. This method enabled the reliable isolation of CTCs from 66% of lung and 60% of breast cancer (both epithelial) patient samples, as well as in 83% of melanoma (mesenchymal) samples. Interestingly, we observed special populations of CTCs that were extensively covered by platelets, as well as CTC-leukocyte clusters. Because these cloaked CTCs often escape conventional positive and negative isolation mechanisms, further characterization of these cells may uncover important yet overlooked biological information in blood-borne metastasis and cancer immunology.

  4. Platelet neuropeptide Y is critical for ischemic revascularization in mice.

    Science.gov (United States)

    Tilan, Jason U; Everhart, Lindsay M; Abe, Ken; Kuo-Bonde, Lydia; Chalothorn, Dan; Kitlinska, Joanna; Burnett, Mary Susan; Epstein, Stephen E; Faber, James E; Zukowska, Zofia

    2013-06-01

    We previously reported that the sympathetic neurotransmitter neuropeptide Y (NPY) is potently angiogenic, primarily through its Y2 receptor, and that endogenous NPY is crucial for capillary angiogenesis in rodent hindlimb ischemia. Here we sought to identify the source of NPY responsible for revascularization and its mechanisms of action. At d 3, NPY(-/-) mice demonstrated delayed recovery of blood flow and limb function, consistent with impaired collateral conductance, while ischemic capillary angiogenesis was reduced (~70%) at d 14. This biphasic temporal response was confirmed by 2 peaks of NPY activation in rats: a transient early increase in neuronally derived plasma NPY and increase in platelet NPY during late-phase recovery. Compared to NPY-null platelets, collagen-activated NPY-rich platelets were more mitogenic (~2-fold vs. ~1.6-fold increase) for human microvascular endothelial cells, and Y2/Y5 receptor antagonists ablated this difference in proliferation. In NPY(+/+) mice, ischemic angiogenesis was prevented by platelet depletion and then restored by transfusion of platelets from NPY(+/+) mice, but not NPY(-/-) mice. In thrombocytopenic NPY(-/-) mice, transfusion of wild-type platelets fully restored ischemia-induced angiogenesis. These findings suggest that neuronally derived NPY accelerates the early response to femoral artery ligation by promoting collateral conductance, while platelet-derived NPY is critical for sustained capillary angiogenesis.

  5. Different training schedules influence platelet aggregation in show jumping horses.

    Science.gov (United States)

    Giannetto, C; Arfuso, F; Fazio, F; Giudice, E; Pietro, S Di; Bruschetta, D; Piccione, G

    2017-03-28

    Depending on the intensity, duration and type of physical exercise, equine metabolism has to adapt to nervous, cardiovascular, endocrine and respiratory system requirements. In horses, exercise and training are known to have considerable effects on the mechanisms of hemostatic system involving platelet activity. The aim of the present study was to evaluate the effect of different training schedules on platelet aggregation in 15 Italian Saddle jumping horses. Animals were divided into three equal groups: Group A was subjected to a high intensity-training program; group B to a light training program, group C included sedentary horses. From each animal, blood samples were collected by jugular venipuncture at rest on the 1st, 3rd and 5th days, and afterwards, once a week, for a total of 5 weeks data recording, in order to assess the maximum degree of platelet aggregation and the initial velocity of aggregation (slope) platelet aggregation. Two-way analysis of variance (ANOVA) showed a significant effect of the different training schedules on studied parameters. The results revealed a different degree of platelet aggregation and a different initial velocity of platelet aggregation that changes during the different training schedules in horses that could represent a different protective endothelial mechanism. These findings could have an important role for a clearer knowledge of the physiological reference values of platelet aggregation and for a better interpretation of these variations during the training.

  6. The influence of platelet membranes on tumour cell behaviour.

    Science.gov (United States)

    Coupland, L A; Hindmarsh, E J; Gardiner, E E; Parish, C R

    2017-06-01

    The significant role of platelets in the protection of tumour cells from immune attack and shear forces and the promotion of tumour cell extravasation from the bloodstream in the process of haematogenous metastasis have been extensively studied. The role of platelets, and in particular platelet membranes, in the promotion of a more metastatic phenotype in tumour cells is a more recent and, therefore, less well-recognised area of research. This review article summarises studies that have focused on the impact of tumour cell interactions with platelets and platelet membranes on tumour cell behaviour in vitro and in vivo. Furthermore, the gene expression changes that occur within tumour cells following contact with platelet membranes are also extensively reviewed. Overall, the interaction of platelet membranes with tumour cells results in a more invasive phenotype and the promotion of epithelial to mesenchymal transition with our own genetic studies revealing that matrix metalloproteinase-1, plasminogen activator inhibitor-1 and interleukin-8 are globally upregulated in a range of tumour cell lines.

  7. Elevated hematocrit enhances platelet accumulation following vascular injury.

    Science.gov (United States)

    Walton, Bethany L; Lehmann, Marcus; Skorczewski, Tyler; Holle, Lori A; Beckman, Joan D; Cribb, Jeremy A; Mooberry, Micah J; Wufsus, Adam R; Cooley, Brian C; Homeister, Jonathan W; Pawlinski, Rafal; Falvo, Michael R; Key, Nigel S; Fogelson, Aaron L; Neeves, Keith B; Wolberg, Alisa S

    2017-05-04

    Red blood cells (RBCs) demonstrate procoagulant properties in vitro, and elevated hematocrit is associated with reduced bleeding and increased thrombosis risk in humans. These observations suggest RBCs contribute to thrombus formation. However, effects of RBCs on thrombosis are difficult to assess because humans and mice with elevated hematocrit typically have coexisting pathologies. Using an experimental model of elevated hematocrit in healthy mice, we measured effects of hematocrit in 2 in vivo clot formation models. We also assessed thrombin generation, platelet-thrombus interactions, and platelet accumulation in thrombi ex vivo, in vitro , and in silico. Compared with controls, mice with elevated hematocrit (RBC HIGH ) formed thrombi at a faster rate and had a shortened vessel occlusion time. Thrombi in control and RBC HIGH mice did not differ in size or fibrin content, and there was no difference in levels of circulating thrombin-antithrombin complexes. In vitro, increasing the hematocrit increased thrombin generation in the absence of platelets; however, this effect was reduced in the presence of platelets. In silico, direct numerical simulations of whole blood predicted elevated hematocrit increases the frequency and duration of interactions between platelets and a thrombus. When human whole blood was perfused over collagen at arterial shear rates, elevating the hematocrit increased the rate of platelet deposition and thrombus growth. These data suggest RBCs promote arterial thrombosis by enhancing platelet accumulation at the site of vessel injury. Maintaining a normal hematocrit may reduce arterial thrombosis risk in humans. © 2017 by The American Society of Hematology.

  8. A meta-analysis and genome-wide association study of platelet count and mean platelet volume in african americans.

    Directory of Open Access Journals (Sweden)

    Rehan Qayyum

    Full Text Available Several genetic variants associated with platelet count and mean platelet volume (MPV were recently reported in people of European ancestry. In this meta-analysis of 7 genome-wide association studies (GWAS enrolling African Americans, our aim was to identify novel genetic variants associated with platelet count and MPV. For all cohorts, GWAS analysis was performed using additive models after adjusting for age, sex, and population stratification. For both platelet phenotypes, meta-analyses were conducted using inverse-variance weighted fixed-effect models. Platelet aggregation assays in whole blood were performed in the participants of the GeneSTAR cohort. Genetic variants in ten independent regions were associated with platelet count (N = 16,388 with p<5×10(-8 of which 5 have not been associated with platelet count in previous GWAS. The novel genetic variants associated with platelet count were in the following regions (the most significant SNP, closest gene, and p-value: 6p22 (rs12526480, LRRC16A, p = 9.1×10(-9, 7q11 (rs13236689, CD36, p = 2.8×10(-9, 10q21 (rs7896518, JMJD1C, p = 2.3×10(-12, 11q13 (rs477895, BAD, p = 4.9×10(-8, and 20q13 (rs151361, SLMO2, p = 9.4×10(-9. Three of these loci (10q21, 11q13, and 20q13 were replicated in European Americans (N = 14,909 and one (11q13 in Hispanic Americans (N = 3,462. For MPV (N = 4,531, genetic variants in 3 regions were significant at p<5×10(-8, two of which were also associated with platelet count. Previously reported regions that were also significant in this study were 6p21, 6q23, 7q22, 12q24, and 19p13 for platelet count and 7q22, 17q11, and 19p13 for MPV. The most significant SNP in 1 region was also associated with ADP-induced maximal platelet aggregation in whole blood (12q24. Thus through a meta-analysis of GWAS enrolling African Americans, we have identified 5 novel regions associated with platelet count of which 3 were replicated in other ethnic

  9. Dabigatran and rivaroxaban do not affect AA- and ADP-induced platelet aggregation in patients receiving concomitant platelet inhibitors.

    Science.gov (United States)

    Olivier, Christoph B; Weik, Patrick; Meyer, Melanie; Weber, Susanne; Diehl, Philipp; Bode, Christoph; Moser, Martin; Zhou, Qian

    2016-08-01

    Dabigatran and rivaroxaban are novel, vitamin K-independent oral anticoagulants (NOACs) and act via antagonism of the coagulation factor (F) IIa (dabigatran) or FXa (rivaroxaban), respectively. Compared to vitamin-K-antagonists, NOACs have shown non-inferiority of risk and benefit in patients with non valvular atrial fibrillation (AF). In clinical practice there is increasing use of NOACs combined with platelet inhibitors in patients with AF and coronary artery disease. However, whether NOACs affect the function of platelet inhibitors remains incompletely known. This observational study aimed to assess the platelet function in patients receiving dabigatran or rivaroxaban and concomitant platelet inhibitors. A single centre observational study was performed analysing the platelet aggregation of patients treated with dabigatran or rivaroxaban with or without concomitant platelet inhibitors. Measurements before the initiation of NOAC therapy served as the respective control group. Platelet aggregation was measured by multiple electrode aggregometry and was induced with adenosine diphosphate (ADP, 6.5 µM) and arachidonic acid (AA, 0.5 mM), respectively. In order to evaluate whether NOACs interact with platelet inhibition by ASA or the P2Y12-antagonist clopidogrel, 87 patients were grouped according to their concomitant antiplatelet medication. Comparing the ADP- and AA-induced platelet aggregation in patients without concomitant platelet inhibitors (n = 45) no significant differences under therapy with dabigatran (d) or rivaroxaban (r) compared to the control group (c) were observed. In patients taking clopidogrel as a concomitant platelet inhibitor (n = 21), neither dabigatran nor rivaroxaban affected the ADP-induced platelet aggregation (c 20 ± 11, d 21 ± 14, r 18 ± 8 AU*min, p = 0.200). Patients receiving dabigatran or rivaroxaban in combination with ASA (n = 42; 21 ASA only, 21 ASA + clopidogrel) showed no significant differences of the AA

  10. Effect of platelet orientation on the properties of alumina platelet zirconia matrix composites

    DEFF Research Database (Denmark)

    Toft Sørensen, O.; Li, W.-Y.

    1996-01-01

    Platelet alignment in Al2O3pl - TZ3YS composites formed by injection moulding, slip casting, and tape casting, has been examined. Mechanical properties have been determined in terms of flexural strength and fracture toughness, with respect to materials formed by different techniques, and to the p...... 220 and 300 degrees C, which is approximately in the same range as for the matrix....

  11. Inhibitory effect of trichothecene mycotoxins on bovine platelets stimulated by platelet activating factor.

    OpenAIRE

    Gentry, P A; Ross, M L; Bondy, G S

    1987-01-01

    Several species of fungi, which infect cereals and grains, can produce a class of compounds, known as trichothecene mycotoxins, which is characterized by a substituted epoxy-trichothecene ring structure. Cattle are susceptible to intoxication from feeds contaminated with T-2 toxin, one of the more potent trichothecene mycotoxins, while swine refuse to ingest feed contaminated with T-2 toxin. The bovine platelet has been used as a model cell system to evaluate the effects of T-2 toxin and its ...

  12. Human platelet calmodulin-binding proteins: Ca2+-dependent proteolysis upon platelet activation

    International Nuclear Information System (INIS)

    Wallace, R.W.; Tallant, E.A.; McManus, M.C.

    1986-01-01

    Calmodulin (CaM)-binding proteins have been identified in human platelets using Western blotting techniques and 125 I-CaM. Ten distinct proteins with molecular weights of 245, 225K, 175K, 150K, 90K, 82K(2), 60K and 41K(2) bound 125 I-CaM in a Ca 2+ -dependent manner; the binding was blocked by both trifluoperazine and nonradiolabeled CaM. The 225K and 90K proteins were labeled by antisera against myosin light chain kinase (MLCK); the 60K and one of the 82K proteins were identified as the CaM-dependent phosphatase and caldesmon. The remaining proteins have not yet been identified. Most of the CaM-binding proteins were degraded upon addition of Ca 2+ to a platelet homogenate; the degradation could be blocked by either EGTA, leupeptin or N-ethyl-maleimide which suggests that it was due to a Ca 2+ -dependent protease. Activation of intact platelets by thrombin, ADP, collagen and the Ca 2+ -ionophores A23187 and ionomycin under conditions which promote platelet aggregation (i.e. stirring with extracellular Ca 2+ ) also resulted in limited proteolysis of CaM-binding proteins including those labeled with anti-MLCK and the phosphatase. Many Ca 2+ /CaM-regulated enzymes have been shown to be irreversibly activated in vitro by limited proteolysis. Their data indicates that limited proteolysis also occurs in vivo; under certain conditions proteolysis may be an important physiological mechanism for irreversibly activating Ca 2+ /CaM-regulated enzymes

  13. Platelet transfusion practice in a tertiary care hospital

    International Nuclear Information System (INIS)

    Rehman, Z.; Alam, M.

    2002-01-01

    Objective: Pakistan is a developing country where platelet concentrates are prepared and administered to patients in only a few large centres of the country. A study was designed for appraisal of the current situation and to review the progress made so far. Design: It was a prospective, non-interventional study. Place and duration of study: The study was conducted at PNS Shifa, Karachi from January, 1995 to December, 1998. Subjects and Methods: During this study 588 random donor platelet concentrates were transfused to 66 patients 148 occasions. Random donor platelet concentrates were prepared by fractionation of whole blood using triple blood collecting bags. Pre-transfusion and one hour posttransfusion platelet counts of the patients were done. The efficacy of the platelet transfusion was monitored by noting the clinical response as well as doing one hour posttransfusion corrected counts increment (CCI).Results: On 114 (77%) occasions platelets were transfused prophylactically and 34 (23%) times therapeutically to stop major bleeding episodes. The mean pre-transfusion platelet count varied from 15.5 x 10/sup 9/1 to 28.5 x 10/sup 9/l in different clinical conditions. On average, 4 random donor platelet concentrates were administered on each occasion. The best response was observed in patients of aplastic anaemia and worst in cases of disseminated intravascular coagulation (DIC). Conclusion: Platelet concentrates administration was inappropriate in significant number of patients, therefore, each hospital should form transfusion committee to review transfusion practices guidelines for blood components usage and compliance to these guidelines by the clinicians. (author)

  14. 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

  15. Platelet reactive alloantibodies responsible for immune thrombocytopenia in Malay population

    Directory of Open Access Journals (Sweden)

    Mohd I. Armawai

    2014-10-01

    Full Text Available Background: Alloantibodies against human platelet alloantigens (HPAs are responsible for the development of platelet transfusion refractoriness (PTR in patients receiving random platelets and bleeding disorder in babies with fetal neonatal alloimmune thrombocytopenia (FNAIT. Recently, our results based on the analysis of the allelic distribution of HPAs indicated that immunization may occur among Malay. In this study, we sought to analyze the frequencies of platelet reactive alloantibodies responsible for FNAIT and PTR in Malaysia.Methods: Sera from suspected FNAIT (n = 295 and PTR (n = 74 were collected in five years period (2008-2013 and tested for the presence of platelet reactive antibodies by the use of antigen capture assay.Results: In 5/74 (5.41% platelet specific antibodies against HPA-2b (n = 1, HPA-5a (n = 1, HPA-5b (n = 1, HPA-15b (n = 2 could be identified in our PTR cohort. In FNAIT cohort, platelet specific alloantibodies could be detected in 18 sera (6.10% consisting anti-HPA-1a (n = 1, anti-HPA-3a (n = 3, anti-HPA-5a (n = 6, anti-HPA-5b (n = 6, anti-HPA-15a (n = 1, and anti-HPA-15b (n = 1.Conclusion: Our study indicates that anti-HPA-3, -HPA-5 and -HPA-15 antibodies seems to be the most platelet specific antibodies involved in FNAIT and PTR cases in Malaysian population. Since similar HPA allelic distribution among Malaysian and Indonesian populations have been observed, immunization against these three HPA systems are expected to be the most potential risk of alloimmune mediated platelet disorders in Indonesia.

  16. Exposure to acrolein by inhalation causes platelet activation

    International Nuclear Information System (INIS)

    Sithu, Srinivas D.; Srivastava, Sanjay; Siddiqui, Maqsood A.; Vladykovskaya, Elena; Riggs, Daniel W.; Conklin, Daniel J.; Haberzettl, Petra; O'Toole, Timothy E.; Bhatnagar, Aruni; D'Souza, Stanley E.

    2010-01-01

    Acrolein is a common air pollutant that is present in high concentrations in wood, cotton, and tobacco smoke, automobile exhaust and industrial waste and emissions. Exposure to acrolein containing environmental pollutants such as tobacco smoke and automobile exhaust has been linked to the activation of the coagulation and hemostasis pathways and thereby to the predisposition of thrombotic events in human. To examine the effects of acrolein on platelets, adult male C57Bl/6 mice were subjected acute (5 ppm for 6 h) or sub-chronic (1 ppm, 6 h/day for 4 days) acrolein inhalation exposures. The acute exposure to acrolein did not cause pulmonary inflammation and oxidative stress, dyslipidemia or induce liver damage or muscle injury. Platelet GSH levels in acrolein-exposed mice were comparable to controls, but acrolein-exposure increased the abundance of protein-acrolein adducts in platelets. Platelets isolated from mice, exposed to both acute and sub-chronic acrolein levels, showed increased ADP-induced platelet aggregation. Exposure to acrolein also led to an increase in the indices of platelet activation such as the formation of platelet-leukocyte aggregates in the blood, plasma PF4 levels, and increased platelet-fibrinogen binding. The bleeding time was decreased in acrolein exposed mice. Plasma levels of PF4 were also increased in mice exposed to environmental tobacco smoke. Similar to inhalation exposure, acrolein feeding to mice also increased platelet activation and established a pro-thrombotic state in mice. Together, our data suggest that acrolein is an important contributing factor to the pro-thrombotic risk in human exposure to pollutants such as tobacco smoke or automobile exhaust, or through dietary consumption.

  17. Sulfatides partition disabled-2 in response to platelet activation.

    Directory of Open Access Journals (Sweden)

    Karen E Drahos

    Full Text Available BACKGROUND: Platelets contact each other at the site of vascular injury to stop bleeding. One negative regulator of platelet aggregation is Disabled-2 (Dab2, which is released to the extracellular surface upon platelet activation. Dab2 inhibits platelet aggregation through its phosphotyrosine-binding (PTB domain by competing with fibrinogen for alphaIIbbeta3 integrin receptor binding by an unknown mechanism. METHODOLOGY/PRINCIPAL FINDINGS: Using protein-lipid overlay and liposome-binding assays, we identified that the N-terminal region of Dab2, including its PTB domain (N-PTB, specifically interacts with sulfatides. Moreover, we determined that such interaction is mediated by two conserved basic motifs with a dissociation constant (K(d of 0.6 microM as estimated by surface plasmon resonance (SPR analysis. In addition, liposome-binding assays combined with mass spectroscopy studies revealed that thrombin, a strong platelet agonist, cleaved N-PTB at a site located between the basic motifs, a region that becomes protected from thrombin cleavage when bound to sulfatides. Sulfatides on the platelet surface interact with coagulation proteins, playing a major role in haemostasis. Our results show that sulfatides recruit N-PTB to the platelet surface, sequestering it from integrin receptor binding during platelet activation. This is a transient recruitment that follows N-PTB internalization by an actin-dependent process. CONCLUSIONS/SIGNIFICANCE: Our experimental data support a model where two pools of Dab2 co-exist at the platelet surface, in both sulfatide- and integrin receptor-bound states, and their balance controls the extent of the clotting response.

  18. Platelet abnormalities in a dog suffering from gangrenous mastitis by Staphylococcus aureus infection.

    Science.gov (United States)

    Hasegawa, T; Fujii, M; Fukada, T; Tsuji, C; Fujita, T; Goto, Y; Shinjo, T; Ogawa, H

    1993-02-01

    Severe gangrenous mastitis due to Staphylococcus aureus infection was diagnosed in a 7 year-old intact female beagle which was presented with swelling of mammary glands after dystocia. Leukocytosis (25,200-48,600/microliters), decreased platelets (107,000-179,000/microliters), and abnormal platelet pattern continued during the critical condition. Consistent with platelet pattern, large platelets were observed in the blood smear. The number of leukocytes and platelets rapidly returned to normal during treatment, and the platelet pattern was also restored. The number and pattern of platelet may provide a clue for the evaluation of the clinical condition and/or severity of the lesions in the dog with mastitis.

  19. Revascularization of Immature Necrotic Teeth: Platelet rich Fibrin an Edge over Platelet rich Plasma

    Directory of Open Access Journals (Sweden)

    Neelam Mittal

    2012-03-01

    Full Text Available Introduction: Revascularization is one such entity that has found its clinical application in the field of endodontics for the manage-ment of immature permanent necrotic teeth. The protocols for revascularization of such teeth focus especially on delivery of stem cells and scaffolds in a nonsurgical manner rather than concentrated growth micro molecules.The hypothesis: This article proposes the role of platelet concentrates such as platelet rich fibrin (PRF and platelet rich plasma (PRP in accelerating the regenerative process in such teeth. PRF unlike PRP is associated with slow, continuous and substantial re-lease of morphogens. It is hypothesized further if PRF instead of PRP when placed through immature apices in an orthograde manner can open newer gates for fast and controlled growth in young, ne-crotic, non-infected teeth.Evaluation of the hypothesis: Enhancement of the healing kinetics can be evaluated by change in size of periapical radiolucency, thickness of the dentinal walls, root elongation and apical closure compared between preoperative and postoperative standardized two dimensional/three dimensional radiographs taken on regular follow ups.

  20. 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

  1. Dual roles for hepatic lectin receptors in the clearance of chilled platelets

    DEFF Research Database (Denmark)

    Rumjantseva, Viktoria; Grewal, Prabhjit K; Wandall, Hans H

    2009-01-01

    Rapid chilling causes glycoprotein-Ib (GPIb) receptors to cluster on blood platelets. Hepatic macrophage beta(2) integrin binding to beta-N-acetylglucosamine (beta-GlcNAc) residues in the clusters leads to rapid clearance of acutely chilled platelets after transfusion. Although capping the beta-G...... transfusion. Inhibition of chilled platelet clearance by both beta(2) integrin and Ashwell-Morell receptors may afford a potentially simple method for storing platelets in the cold.......Rapid chilling causes glycoprotein-Ib (GPIb) receptors to cluster on blood platelets. Hepatic macrophage beta(2) integrin binding to beta-N-acetylglucosamine (beta-GlcNAc) residues in the clusters leads to rapid clearance of acutely chilled platelets after transfusion. Although capping the beta......-Morell receptor binding, become increasingly involved in platelet removal. Macrophages rapidly removed a large fraction of transfused platelets independent of their storage conditions. With prolonged platelet chilling, hepatocyte-dependent clearance further diminishes platelet recovery and survival after...

  2. In-111 platelet scintigraphy: carotid atherosclerosis and stroke

    International Nuclear Information System (INIS)

    Powers, W.J.

    1984-01-01

    An association between atherosclerosis of the internal carotid artery and ischemia or infarction of the ipsilateral cerebral hemisphere has been demonstrated by numerous radiographic and pathologic studies. The precise mechanism by which carotid atherosclerosis causes these problems, however, remains unclear. Several observations suggest that fibrin-platelet thrombi form on atherosclerotic plaques in the neck arteries and then embolize distally into the intracranial circulation. Unfortunately, platelet embolization does not adequately explain a variety of clinical and pathological findings in patients with cerebrovascular disease. This editorial will discuss these findings. It is obvious that the understanding of the role of platelets in the pathogenesis of ischemic cerebrvascular disease is far from complete

  3. Adhesion of platelets to microcapsules and the role of complement.

    Science.gov (United States)

    Muramatsu, N; Kondo, T

    1984-07-11

    Rabbit platelets rapidly adhered to carboxylated polyamide microcapsules through the adsorbed layer of plasma components. These components were found to be heat-labile proteins, which exist in fresh serum, and to demand calcium ions to function. These findings ascribed the components to the complement system. In fact, a good correlation was obtained between platelet adhesion to, and complement fixation by, the microcapsules. Moreover, the activation of the complement system by the microcapsules was assumed to proceed via the classical pathway. It was concluded that adhesion of platelets to the microcapsules is brought about by immune adherence.

  4. Emerging Evidence for Platelets as Immune and Inflammatory Effector Cells

    Directory of Open Access Journals (Sweden)

    Matthew Thomas Rondina

    2014-12-01

    Full Text Available While traditionally recognized for their roles in hemostatic pathways, emerging evidence demonstrates that platelets have previously unrecognized, dynamic roles that span the immune continuum. These newly-recognized platelet functions, including the secretion of immune mediators, interactions with endothelial cells, monocytes, and neutrophils, toll-like receptor (TLR mediated responses, and induction of neutrophil extracellular trap (NET formation, bridge thrombotic and inflammatory pathways and contribute to host defense mechanisms against invading pathogens. In this focused review, we highlight several of these emerging aspects of platelet biology and their implications in clinical infectious syndromes.

  5. Macroscopic domain formation in the platelet plasma membrane

    DEFF Research Database (Denmark)

    Bali, Rachna; Savino, Laura; Ramirez, Diego A.

    2009-01-01

    phase behavior of the platelet plasma membrane by FTIR, and compare it to a POPC/Sphingomyelin/Cholesterol model representing the outer leaflet composition. We find that this model closely reflects the platelet phase behavior. Previous work has shown that the platelet plasma membrane presents......There has been ample debate on whether cell membranes can present macroscopic lipid domains as predicted by three-component phase diagrams obtained by fluorescence microscopy. Several groups have argued that membrane proteins and interactions with the cytoskeleton inhibit the formation of large...

  6. Method of producing nano-scaled inorganic platelets

    Science.gov (United States)

    Zhamu, Aruna; Jang, Bor Z.

    2012-11-13

    The present invention provides a method of exfoliating a layered material (e.g., transition metal dichalcogenide) to produce nano-scaled platelets having a thickness smaller than 100 nm, typically smaller than 10 nm. The method comprises (a) dispersing particles of a non-graphite laminar compound in a liquid medium containing therein a surfactant or dispersing agent to obtain a stable suspension or slurry; and (b) exposing the suspension or slurry to ultrasonic waves at an energy level for a sufficient length of time to produce separated nano-scaled platelets. The nano-scaled platelets are candidate reinforcement fillers for polymer nanocomposites.

  7. Platelet-rich plasma: applications in dermatology.

    Science.gov (United States)

    Conde Montero, E; Fernández Santos, M E; Suárez Fernández, R

    2015-03-01

    In recent years, the use of platelet-rich plasma has increased notably in a range of diseases and settings. Uses of these products now go beyond skin rejuvenation therapy in patients with facial ageing. Good outcomes for other dermatological indications such as skin ulcers and, more recently, alopecia have been reported in case series and controlled studies. However, these indications are not currently included in the labeling given that stronger scientific evidence is required to support their real benefits. With the increased use of these products, dermatologists need to become familiar with the underlying biological principles and able to critically assess the quality and outcomes of the studies of these products in different skin diseases. Copyright © 2013 Elsevier España, S.L.U. and AEDV. All rights reserved.

  8. Platelet-rich plasma for osteoarthritis treatment

    Directory of Open Access Journals (Sweden)

    Eduardo Knop

    2016-04-01

    Full Text Available ABSTRACT We conducted a comprehensive and systematic search of the literature on the use of platelet-rich plasma (PRP in the treatment of osteoarthritis, using the Medline, Lilacs, Cochrane and SciELO databases, from May 2012 to October 2013. A total of 23 studies were selected, with nine being controlled trials and, of these, seven randomized, which included 725 patients. In this series, the group receiving PRP showed improvement in pain and joint function compared to placebo and hyaluronic acid. The response lasted up to two years and was better in milder cases. However it was found that there is no standardization in the PRP production method, neither in the number, timing, and volume of applications. Furthermore, the populations studied were not clearly described in many studies. Thus, these results should be analyzed with caution, and further studies with more standardized methods would be necessary for a more consistent conclusion about the PRP role in osteoarthritis.

  9. 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.

  10. 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; Takahashi, Yukinobu; Omura, Ken

    2014-01-01

    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. PMID:24098948

  11. Elemental composition of platelets. Part I. Sampling and sample preparation of platelets for trace-element analysis

    International Nuclear Information System (INIS)

    Iyengar, G.V.; Borberg, H.; Kasperek, K.; Kiem, J.; Siegers, M.; Feinendegen, L.E.; Gross, R.

    1979-01-01

    Sampling of platelets for trace-element analysis poses special problems: obtaining adequate sample materials, achieving a sufficient cell purity, preserving viability (integrity), correcting for trapped plasma, and controlling contamination. We used a blood-cell separator for the primary isolation of platelets from blood, and differential centrifugation in natural plasma to further isolate them. The pyrimidopyrimidine RA233 was used as a stabilizer to maintain viability. 131 I-labeled human serum albumin was used to estimate trapped plasma. Contamination was controlled by using five-times-distilled water to simulate donor's blood in the system and by comparing three fractions: the serum, the first portion of the platelet-rich plasma, and the supernatant plasma after the final centrifugation. Neutron activation analysis was used for the elemental analysis. A single differential centrifugation of the platelet-rich plasma from the blood-cell separator at 400 x g for 8 min was optimum (mean mass fractions: erythrocytes/platelets < 5 mg/g and leukocytes/platelets < 20 mg/g). The trapped plasma in the wet platelet samples amounted to about 0.40 g/g. No appreciable contamination from the sampling system was found for the elements Ag, Cd, Co, Cr, Cs, Cu, Fe, Mo, Rb, Sb, Se, and Zn. 2 figures, 3 tables

  12. Platelet function in stored heparinised autologous blood is not superior to in patient platelet function during routine cardiopulmonary bypass.

    Directory of Open Access Journals (Sweden)

    Rolf C G Gallandat Huet

    Full Text Available BACKGROUND: In cardiac surgery, cardiopulmonary bypass (CPB and unfractionated heparin have negative effects on blood platelet function. In acute normovolemic haemodilution autologous unfractionated heparinised blood is stored ex-vivo and retransfused at the end of the procedure to reduce (allogeneic transfusion requirements. In this observational study we assessed whether platelet function is better preserved in ex vivo stored autologous blood compared to platelet function in the patient during CPB. METHODOLOGY/PRINCIPAL FINDING: We measured platelet aggregation responses pre-CPB, 5 min after the start of CPB, at the end of CPB, and after unfractionated heparin reversal, using multiple electrode aggregometry (Multiplate® with adenosine diphosphate (ADP, thrombin receptor activating peptide (TRAP and ristocetin activated test cells. We compared blood samples taken from the patient with samples taken from 100 ml ex-vivo stored blood, which we took to mimick blood storage during normovolemic haemodilution. Platelet function declined both in ex-vivo stored blood as well as in blood taken from the patient. At the end of CPB there were no differences in platelet aggregation responses between samples from the ex vivo stored blood and the patient. CONCLUSION/SIGNIFICANCE: Ex vivo preservation of autologous blood in unfractionated heparin does not seem to be profitable to preserve platelet function.

  13. A quantitative method to measure human platelet chemotaxis using indium-111-oxine-labeled gel-filtered platelets

    International Nuclear Information System (INIS)

    Lowenhaupt, R.W.; Silberstein, E.B.; Sperling, M.I.; Mayfield, G.

    1982-01-01

    Human blood platelets have been shown to migrate directionally and specifically toward collagen in plasma in vitro. We have developed a new system to monitor this behavior using a linear 7-compartment chamber with 111 In-oxine-labeled gel-filtered platelets. The compartments are separated by various Nuclepore and Millipore filter membranes. Radiolabeled platelets suspended in plasma are placed in the central compartment and the other compartments are filled with platelet-free plasma. When collagen is added to an end compartment, platelets migrate toward that end. The degree of this directed movement or chemotaxis can be measured by counting the radioactivity of the contents of each compartment and then comparing the counts from radiolabeled platelets that have moved to the end that holds the chemotactic inducer with those that have randomly migrated to the opposite end, containing only plasma. This assay system allows quantitative comparisons between the chemotaxis-inducing abilities of different substances and permits the study of soluble materials. Experiments to determine the optimal conditons for the procedure are reported, and the advantages of this new method for the investigation of platelet chemotaxis and the identification of chemotaxins are discussed

  14. A quantitative method to measure human platelet chemotaxis using 111In-oxine-labeled gel-filtered platelets

    International Nuclear Information System (INIS)

    Lowenhaupt, R.W.; Silberstein, E.B.; Sperling, M.I.; Mayfield, G.

    1982-01-01

    Human blood platelets have been shown to migrate directionally and specifically toward collagen in plasma in vitro. We have developed a new system to monitor this behavior using a linear 7-compartment chamber with 111 In-oxine-labeled gel-filtered platelets. The compartments are separated by various Nuclepore and Millipore filter membranes. Radiolabeled platelets suspended in plasma are placed in the central compartment and the other compartments are filled with platelet-free plasma. When collagen is added to an end compartment, platelets migrate toward that end. The degree of this directed movement or chemotaxis can be measured by counting the radioactivity of the contents of each compartment and then comparing the counts from radiolabeled platelets that have moved to the end that holds the chemotactic inducer with those that have randomly migrated to the opposite end, containing only plasma. This assay system allows quantitative comparisons between the chemotaxis-inducing abilities of different substances and permits the study of soluble materials. Experiments to determine the optimal conditions for the procedure are reported, and the advantages of this new method for the investigation of platelet chemotaxis and the identification of chemotaxins are discussed

  15. Platelet accumulation in abdominal aortic aneurysm and the effect of antiplatelet drugs; Assessment by indium platelet scintigraphy

    Energy Technology Data Exchange (ETDEWEB)

    Etami, Hideki (Osaka-Minami National Hospital, Kawachi-nagano (Japan)); Kimura, Kazufumi; Isaka, Yoshinari (and others)

    1992-06-01

    A dual tracer technique using {sup 111}In labeled platelets and {sup 99m}Tc labeled human serum albumin was applied to evaluate the in vivo thrombogenicity in 12 cases with abdominal aortic aneurysm (AAA) and the effect of antiplatelet drug on the thrombogenicity. The magnitude of platelet accumulation at AAA was expressed as the ratio of radioactivity of {sup 111}In platelets on the vascular wall to those in the blood pool (PAI; platelet accumulation index). Of the 12 patients with AAA, 11 had positive studies on baseline imaging and 1 had equivocally positive image. The PAI value (Mean{+-}SD) over the AAA was 53.8{+-}34.1% as compared to -8.6{+-}4.4% in the control group (p<0.01). Seven patients with an AAA and positive baseline images were restudied during platelet active drug with 325 mg of aspirin. During treatment with aspirin, of 7 patients, 5 had positive images, of which 3 were decreased and others unchanged compared to baseline studies, 1 equivocally positive one and one negative one. The PAI value during treatment (21.9{+-}18.6%) was significantly decreased compared to those in baseline study (52.1{+-}23.9%). Our results suggest that the method used for platelet imaging in the present study may be useful for studying the in vivo thrombogenicity and the effect of platelet active drugs in AAA. (author).

  16. Effects of altered platelet number on pulmonary hypertension and platelet sequestration in monocrotaline pyrrole-treated rats

    International Nuclear Information System (INIS)

    White, S.M.; Wagner, J.G.; Roth, R.A.

    1989-01-01

    To study the role of platelets in monocrotaline pyrrole (MCTP)-induced pulmonary hypertension, pulmonary sequestration of 111In-labeled platelets in rats treated with MCTP and anti-rat platelet serum (PAS) was examined. Lung injury from a single, intravenous injection of MCTP (3.5 mg/kg) at Day 8 was evident as elevated lung weight and lavage fluid protein and lactate dehydrogenase activity. Additionally, right ventricular hypertrophy and elevated pulmonary arterial pressures (PAP) occurred. Treatment with PAS on Days 6-8 did not affect the lung injury but resulted in an attenuation of the pulmonary hypertensive response. Pulmonary platelet sequestration was also decreased in PAS-treated rats, yet the sequestration in the lungs of MCTP-treated rats that received PAS was significantly higher than that in the lungs of N,N-dimethylformamide (DMF) controls. MCTP-treated rats receiving control serum (CS) tended to sequester more 111In-labeled platelets than respective DMF controls, but this was not statistically significant. Blood platelet half-life was unaltered in rats receiving CS. When rats were treated similarly with MCTP and PAS and were killed at 18 days, the attenuation of the pulmonary hypertensive response previously described was not observed, and lung injury was more extensive than when CS was given. Apparently, platelet depletion delayed the development of the pulmonary hypertensive response. Supranormal platelet numbers produced by splenectomy did not affect MCTP-induced lung injury or the elevation in PAP. These results support the hypothesis that the development of MCTP-induced pulmonary hypertension is mediated in part by platelets

  17. 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...

  18. The behaviour of platelets in natural diamonds and the development of a new mantle thermometer

    Science.gov (United States)

    Speich, L.; Kohn, S. C.; Bulanova, G. P.; Smith, C. B.

    2018-05-01

    Platelets are one of the most common defects occurring in natural diamonds but their behaviour has not previously been well understood. Recent technical advances, and a much improved understanding of the correct interpretation of the main infrared (IR) feature associated with platelets (Speich et al. 2017), facilitated a systematic study of platelets in 40 natural diamonds. Three different types of platelet behaviour were identified here. Regular diamonds show linear correlations between both B-centre concentrations and platelet density and also between platelet size and platelet density. Irregular diamonds display reduced platelet density due to platelet breakdown, anomalously large or small platelets and a larger platelet size distribution. These features are indicative of high mantle storage temperatures. Finally, a previously unreported category of subregular diamonds is defined. These diamonds experienced low mantle residence temperatures and show smaller than expected platelets. Combining the systematic variation in platelet density with temperatures of mantle storage, determined by nitrogen aggregation, we can demonstrate that platelet degradation proceeds at a predictable rate. Thus, in platelet-bearing diamonds where N aggregation is complete, an estimate of annealing temperature can now be made for the first time.

  19. How do I … manage the platelet transfusion-refractory patient?

    Science.gov (United States)

    Juskewitch, Justin E; Norgan, Andrew P; De Goey, Steven R; Duellman, Patti M; Wakefield, Laurie L; Gandhi, Manish J; Stubbs, James R; Kreuter, Justin D

    2017-12-01

    Platelet transfusion-refractoriness is a challenging and expensive clinical scenario seen most often in patients with hematologic malignancies. Although the majority of platelet transfusion-refractory cases are due to nonimmune causes, a significant minority are caused by alloimmunization against Class I human leukocyte antigens (HLAs) or human platelet antigens (HPAs). Such platelet transfusion-refractory patients can be effectively managed with appropriate antigen-negative products. Our institution has developed a diagnostic and management algorithm for the platelet transfusion-refractory patient with an early focus on identifying those cases caused by immune-mediated factors. Using physical platelet cross-matches to initially classify platelet transfusion-refractory patients as immune-mediated or not, cross-match-compatible inventory is then provided to immune-mediated patients, whereas subsequent HLA (with or without HPA) testing is performed. Our blood donor program performs Class I HLA typing of all repeat platelet donors to facilitate the identification of antigen-negative platelet units (virtual cross-matching) as well as the recruitment of HLA-matched donors. The platelet transfusion-refractoriness algorithm realizes an initial net cost savings once two apheresis platelets are saved from use for each newly identified, immune-mediated platelet transfusion-refractory patient. An algorithm utilizing physical platelet cross-matches, Class I HLA and HPA antibody testing, and upfront Class I HLA typing of platelet donors leads to overall resource savings and improved clinical management for platelet transfusion-refractory patients. © 2017 AABB.

  20. Sebastian syndrome with abnormal platelet response to ristocetin.

    Science.gov (United States)

    Redman, Rachel; Shunkwiler, Sara M; Harris, Neil S; Kedar, Amos; Clapp, William L

    2008-01-01

    Sebastian syndrome is characterized by enlarged platelets and Döhle-like body leukocyte inclusions. This syndrome is an MYH-9-related disease, a group that also includes May-Hegglin anomaly and Fechtner syndrome. The differential diagnosis of the MYH-9 diseases requires ultrastructural studies. Certain in vitro aggregation responses may be abnormal in these conditions. A 6-month-old boy presented with macrothrombocytopenia but no overt bleeding tendency. Giant platelets and Döhle-like body leukocyte inclusions were present in blood smears from both the patient and his mother. Electron microscopy confirmed ultrastructural features consistent with Sebastian syndrome. Platelet aggregation studies were normal except for an impaired response to the agonist ristocetin. In this patient peripheral blood analyses and platelet aggregation studies revealed disease features shared with the Bernard-Soulier syndrome, but this syndrome was excluded by cellsurface glycoprotein analysis.

  1. Impact of Silver Nanoparticles on Haemolysis, Platelet Function and Coagulation

    Directory of Open Access Journals (Sweden)

    Julie Laloy

    2014-09-01

    Full Text Available Silver nanoparticles (Ag NPs are increasingly used in biomedical applications because of their large antimicrobial spectrum. Data in the literature on the ability of Ag NPs to perform their desired function without eliciting undesirable effects on blood elements are very limited and contradictory. We studied the impact of Ag NPs on erythrocyte integrity, platelet function and blood coagulation. Erythrocyte integrity was assessed by spectrophotometric measurement of haemoglobin release. Platelet adhesion and aggregation was determined by light transmission aggregometry and scanning electron microscopy. The calibrated thrombin generation test was used to study the impact on coagulation cascade. We demonstrated that Ag NPs induced haemolysis. They also increase platelet adhesion without having any impact on platelet aggregation. Finally, they also had procoagulant potential. Bringing all data from these tests together, the no observed effect concentration is 5 μg/mL.

  2. Rethinking platelet function: thrombocytopenia induced immunodeficiency in critical illness

    DEFF Research Database (Denmark)

    Ostrowski, Sisse R; Johansson, Per Ingemar

    2011-01-01

    traditional innate immune cells, platelets are recruited immediately into injured and inflamed tissue, they release immune mediators, express and shed immunologically active membrane receptors, they interact with other immune cells and they recognize and clear pathogens. We hypothesize that thrombocytopenia...

  3. Electrochemical method of producing nano-scaled graphene platelets

    Energy Technology Data Exchange (ETDEWEB)

    Zhamu, Aruna; Jang, Joan; Jang, Bor Z.

    2013-09-03

    A method of producing nano-scaled graphene platelets with an average thickness smaller than 30 nm from a layered graphite material. The method comprises (a) forming a carboxylic acid-intercalated graphite compound by an electrochemical reaction; (b) exposing the intercalated graphite compound to a thermal shock to produce exfoliated graphite; and (c) subjecting the exfoliated graphite to a mechanical shearing treatment to produce the nano-scaled graphene platelets. Preferred carboxylic acids are formic acid and acetic acid. The exfoliation step in the instant invention does not involve the evolution of undesirable species, such as NO.sub.x and SO.sub.x, which are common by-products of exfoliating conventional sulfuric or nitric acid-intercalated graphite compounds. The nano-scaled platelets are candidate reinforcement fillers for polymer nanocomposites. Nano-scaled graphene platelets are much lower-cost alternatives to carbon nano-tubes or carbon nano-fibers.

  4. A sensitive new method of ex vivo platelet deposition

    International Nuclear Information System (INIS)

    Badimon, L.; Fuster, V.; Dewanjee, M.K.; Romero, J.C.

    1982-01-01

    In 1978, an in vivo quantitative method of platelet aggregation based on the increment of weight of a rabbit tendon when superfused with flowing blood (3 ml/min) derived from a carotid artery of a cat and reentering the contralateral jugular vein was reported. TO increase the sensitivity of the method, researches labeled platelets with indium-111 and reinjected them after two hours; then, with a gamma counter, researches quantitated the 111 In-labeled platelets deposited on the superfused rabbit tendon. Results of the radioactivity method and of the weight method were compared. Researchers found that the 111 In-labeling of platelets was more precise and reproducible method, rendering possible the use of a small amount of blood without need for reentry into the venous system

  5. The Role of Platelet and its Interaction with Aspirin

    Directory of Open Access Journals (Sweden)

    Luisa Fernanda Zúñiga Cerón

    2016-04-01

    Conclusion. It is recognized the role of platelet in different physiopathological processes and thus its interaction with aspirin, preventing its aggregation and thrombus formation in the spleen and other organs, this way contributing to the prevention of future cardiovascular events.

  6. Effect of pathogenic yeasts on human platelet aggregation

    Directory of Open Access Journals (Sweden)

    Neiva Teresinha de Jesus Carvalho

    2003-01-01

    Full Text Available We investigated the effects of Candida albicans, Cryptococcus neoformans and the respective culture supernatants on human platelet aggregation (PA. Both yeasts were unable to aggregate the platelets directly. On the other hand, cells of these yeasts significantly (P < 0.01 inhibited PA at concentrations equal to or higher than 1 x 10(6 cells/mL for C. albicans and equal to or higher than 1 x 10(5 cells/mL for C. neoformans. When the supernatants of one-week broth cultures were added to the activated platelets no inhibition in aggregation was observed. Apparently somatic components of these yeasts, but not their metabolic products, exert an antagonistic effect on the aggregation of human platelets, possibly aiding the fungi in their evasion of the microbicidal defense system during vascular dissemination.

  7. Valproic acid modulates platelet and coagulation function ex vivo

    DEFF Research Database (Denmark)

    Bambakidis, Ted; Dekker, Simone E; Halaweish, Ihab

    2017-01-01

    of coagulopathy, it remains unknown whether this is a direct effect of the drug, or the establishment of an overall prosurvival phenotype. We thus conducted an ex-vivo experiment to determine if VPA has an effect on coagulation and platelet function. Ten swine were subjected to traumatic brain injury (TBI......) and hemorrhagic shock (HS). Blood samples were drawn prior to TBI+HS insult (Healthy group) and 2 h following TBI+HS (Shock group). Samples were incubated with VPA or vehicle controls for 1 h. Platelet aggregation was analyzed via impedance aggregometry and coagulation was measured using thromboelastography....... Addition of VPA to the healthy blood did not affect platelet aggregation or coagulation parameters. In shock blood, incubation with VPA significantly reduced collagen-(P = 0.050), arachidonic acid-(P = 0.005), and adenosine diphosphate-(P = 0.023) induced platelet aggregation. VPA also significantly...

  8. Human platelet releasates combined with polyglycolic acid scaffold ...

    Indian Academy of Sciences (India)

    2015-02-04

    Bernardini G, Chellini F, Frediani B, Spreafico A and Santucci A 2015 Human platelet releasates combined with polyglycolic acid scaffold promote ..... 5% FCS (left) and 5% PRPr (right) as different culture supplements. Scale bar: ...

  9. 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 aspirin (sensitivity 0.91, specificity 1.00). A good agreement between the PFA-100 method and optical platelet aggregation was found. Within...

  10. Reduction in mean platelet volume in children with acute bronchiolitis.

    Science.gov (United States)

    Ergül, Ayşe Betül; Torun, Yasemin Altuner; Uytun, Salih; Aslaner, Hümeyra; Kısaaslan, Ayşenur Paç; Şerbetçi, Mahmut Can

    2016-03-01

    Platelets which are known to play a role in inflamation change their shapes when they are activated and this change is reflected in mean platelet volume and platelet distribution width values. Therefore, the mean platelet volume and platelet distribution width values are considered to be beneficial parameters for the diagnosis and treatment of many inflammatory diseases. The aim of the study was to evaluate platelet volume indices in children with acute bronchiolitis. A total of 514 infants who were below the age of 2 years old were evaluated in this study. Three hundred thirteen of these infants were diagnosed with acute bronchiolitis patients and 201 were healthy children. The patients were separated into four groups as mild, moderate, severe bronchiolitis and the control patient group. The groups were evaluated in terms of significant differences in the values of mean platelet volume and platelet distribution width. A p value of <0.05 was considered statistically significant for all results. The mean platelet volume was found to be 6.8±0.6 fL in the patients with mild bronchiolitis attack, 6.7±0.6 fL in the patients with moderate bronchiolitis attack, 6.5±0.5 fL in the patients with severe bronchiolitis attack and 7.3±1.1 fL in the control group. The mean platalet volume was statistically significantly lower in the mild, moderate and severe bronchiolitis attack groups compared to the control group (p=0.000). The platelet distribution width was found to be 17.2%±0.83 in the mild bronchiolitis attack group, 17.1%±0.96 in the moderate bronchiolitis attack group, 17.3%±0.87 in the severe bronchiolitis attack group and 16.9±1.6% in the control patient group. This difference was not statistically significant (p=0.159). The platelet count was statistically significantly higher in the mild, moderate and severe bronchiolitis attack groups compared to the control group (p=0.000). The mean platalet volume is decreased in patients with acute bronchiolitis. It is not

  11. Purification of human platelet-derived growth factor

    International Nuclear Information System (INIS)

    Raines, E.W.; Ross, R.

    1985-01-01

    The paper describes a method for purification of human platelet-derived growth factor (PDGF) from outdated platelet-rich plasma (PRP) using commonly available laboratory reagents and yielding a mitogen purified 800,000-fold over the starting material. [ 3 H]thymidine incorporation into DNA of cultured cells responsive to PDGF represents the most readily available method to follow its purification and define the biological activity of a purified preparation. Other assays to quantitate PDGF include radioreceptor assay and radioimmunoassay

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

    Science.gov (United States)

    2017-12-01

    after death . The term “cadaver” does not include portions of an individual person, such as organs, tissue or blood, that were removed while the...stored in either plasma alone (Plasma, black circles and downward triangles), or in a 65% platelet additive solution, 35% plasma mixture (Intersol... black squares, or Isoplate, black , upward triangles). A, Platelets were stored for three days at 4ºC. Results are shown as percentage of pre-storage

  13. Platelet activation and inflammation markers as emerging risk ...

    African Journals Online (AJOL)

    Platelet activation and inflammation markers were assessed by measuring plasma levels of sP-selectin, platelet factor 4 (PF4), IL-6 and tumor necrosis factor alpha (TNF-α). Results: HIV infected patients had higher levels of sP- selectin, PF4 and IL-6 than uninfected controls (p<0.001). ART naïve subjects had higher levels ...

  14. Microparticles from apoptotic platelets promote resident macrophage differentiation

    OpenAIRE

    Vasina, E M; Cauwenberghs, S; Feijge, M A H; Heemskerk, J W M; Weber, C; Koenen, R R

    2011-01-01

    Platelets shed microparticles not only upon activation, but also upon ageing by an apoptosis-like process (apoptosis-induced platelet microparticles, PMap). While the activation-induced microparticles have widely been studied, not much is known about the (patho)physiological consequences of PMap formation. Flow cytometry and scanning electron microscopy demonstrated that PMap display activated integrins and interact to form microparticle aggregates. PMap were chemotactic for monocytic cells, ...

  15. Platelet aggregation, secretion, and coagulation changes in children with asthma.

    Science.gov (United States)

    Buyukyilmaz, Gonul; Soyer, Ozge U; Buyuktiryaki, Betul; Alioglu, Bulent; Dallar, Yildiz

    2014-10-01

    The chronic inflammation in asthma evolves by cells including eosinophils, mast cells and lymphocytes. Despite their principal function in hemostasis, platelets contribute to pathogenesis of asthma that activation of platelets occurs following antigen provocation and during asthma attack. Our aim was to evaluate the platelet functions and other hemostatic features of children with asthma, both during symptom-free period and asthma attack. We enrolled patients with asthma attack (n = 33), mild intermittent asthma (n = 18), mild persistent asthma (n = 15) and healthy children (n = 20). Demographic characteristics and disease-related features were noted. Platelet aggregation and secretion tests (expressed as ATP release) were performed by lumiaggregometer method by stimulation with collagen, epinephrine, ADP, thrombin, ristocetin and arachidonic acid. Plasma levels of D-dimer, factor VIII (FVIII) and von Willebrand factor (vWF) were assessed. There were no differences in platelet aggregation induced by agonists between study groups. ATP release from platelets of patients with asthma exacerbation induced by ADP was lower compared with mild intermittent asthma (P asthma attack than mild intermittent (P = 0.039) and mild persistent asthma (P = 0.011) and controls (P = 0.018). vWF measurements were higher in children with asthma attack than other study groups (P = 0.001). However, FVIII was increased in patients with severe asthma attack. Asthma is a disease in which many immune cells play a role, one of which is the platelet. Distinctions in platelet secretion profiles and plasma levels of vWF and FVIII provide evidence that coagulation mechanisms might be critical for asthma pathogenesis.

  16. Pathogen-Reduced, Plasmalyte-Extended Stored Platelets (PREPS)

    Science.gov (United States)

    2013-10-01

    maintaining circulating platelet counts in thrombocytopenic cancer patients, transfusion of fresh whole blood in the field might provide adequate platelet...effective contraceptive during the course of the study; 6. Those subjects who will be reinfused within 10 days of their 500 mL WB collection must meet...50 kg (110 pounds). 2. Hematocrit: 38% 3. Oral Temperature: 37.5C 4. Blood Pressure: Systolic 180 mmHg; diastolic 100 mmHg 5. Heart Rate

  17. Clopidogrel discontinuation and platelet reactivity following coronary stenting

    LENUS (Irish Health Repository)

    2011-01-01

    Summary. Aims: Antiplatelet therapy with aspirin and clopidogrel is recommended for 1 year after drug-eluting stent (DES) implantation or myocardial infarction. However, the discontinuation of antiplatelet therapy has become an important issue as recent studies have suggested a clustering of ischemic events within 90 days of clopidogrel withdrawal. The objective of this investigation was to explore the hypothesis that there is a transient ‘rebound’ increase in platelet reactivity within 3 months of clopidogrel discontinuation. Methods and Results: In this prospective study, platelet function was assessed in patients taking aspirin and clopidogrel for at least 1 year following DES implantation. Platelet aggregation was measured using a modification of light transmission aggregometry in response to multiple concentrations of adenosine diphosphate (ADP), epinephrine, arachidonic acid, thrombin receptor activating peptide and collagen. Clopidogrel was stopped and platelet function was reassessed 1 week, 1 month and 3 months later. Thirty-two patients on dual antiplatelet therapy were recruited. Discontinuation of clopidogrel increased platelet aggregation to all agonists, except arachidonic acid. Platelet aggregation in response to ADP (2.5, 5, 10, and 20 μm) and epinephrine (5 and 20 μm) was significantly increased at 1 month compared with 3 months following clopidogrel withdrawal. Thus, a transient period of increased platelet reactivity to both ADP and epinephrine was observed 1 month after clopidogrel discontinuation. Conclusions: This study demonstrates a transient increase in platelet reactivity 1 month after clopidogrel withdrawal. This phenomenon may, in part, explain the known clustering of thrombotic events observed after clopidogrel discontinuation. This observation requires confirmation in larger populations.

  18. Burro aortic collagen: composition and characteristics of interaction with platelets

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, M.D. (Comparative Animal Research Lab., Oak Ridge, TN); Huang, W.O.W.; Cross, F.H.; Lin, K.T.D.

    1979-03-01

    A collagenous protein(s) from the aortas of three aged burros (Equus asinus) was isolated, using an acid (83.5 mM glacial acetic acid) extraction technique and subsequent pepsin digestion of the extracts with extensive dialysis. This protein(s) was then precipitated by adding solid NaCl (w/v, 9.45 g/100 ml) to the dialyzed aortic tissue extracts. The precipitate was collected by ultracentrifugation, concentrated by dissolving in one-fourth the original volume of acetic acid, and again extensively dialyzed. Values for amino acids in residues/1,000 indicated that the extractable aortic material(s) contained substantial amounts of proline, hydroxyproline, lysine, hydroxylysine, cysteine, and all other amino acid residues usually found in collagen. Examination by electrophoresis in sodium dodecyl sulfate polyacrylamide-gel indicated the presence of 5 major polypeptide subunits of the molecular weight range of 116,000 to 300,000. A powerful inducer of platelet aggregation was found in the acid solubilized, pepsin-digested aortic extracts. Human platelets were sensitive to the agent(s) down to 0.1 to 0.2 ..mu..g of aortic solids added to 0.45 ml of platelet-rich plasma. Platelets from goats and sheep were sensitive down to additions of 0.2 ..mu..g of solids, burro platelets to 0.5 to 1 ..mu..g, bovine platelets to 1 to 2 ..mu..g, and swine platelets to 2 to 3 ..mu..g. Thus, this powerful burro aortic collagen-containing material(s) may help to distinguish minor modifications in functional characteristics of platelets from persons or animals suffering from hemostatic or thrombotic disorders.

  19. Effect of genetic and coexisting polymorphisms on platelet response ...

    Indian Academy of Sciences (India)

    platelet aggregation to clopidogrel treatment, respectively (P <0.001). Patients with CYP2C19*2 allele had a higher risk of high on-treatment platelet reactivity than non carriers (adjusted OR, 5.434; 95% CI, 1.918–15.399, P =0.01). The coexistence of CYP2B6*9 (rs8192719) and P2Y12 (rs2046934) and the coexistence of ...

  20. Platelet turnover in stable coronary artery disease - influence of thrombopoietin and low-grade inflammation.

    Directory of Open Access Journals (Sweden)

    Sanne Bøjet Larsen

    Full Text Available BACKGROUND: Newly formed platelets are associated with increased aggregation and adverse outcomes in patients with coronary artery disease (CAD. The mechanisms involved in the regulation of platelet turnover in patients with CAD are largely unknown. AIM: To investigate associations between platelet turnover parameters, thrombopoietin and markers of low-grade inflammation in patients with stable CAD. Furthermore, to explore the relationship between platelet turnover parameters and type 2 diabetes, prior myocardial infarction, smoking, age, gender and renal insufficiency. METHODS: We studied 581 stable CAD patients. Platelet turnover parameters (immature platelet fraction, immature platelet count, mean platelet volume, platelet distribution width and platelet large cell-ratio were determined using automated flow cytometry (Sysmex XE-2100. Furthermore, we measured thrombopoietin and evaluated low-grade inflammation by measurement of high-sensitive CRP and interleukin-6. RESULTS: We found strong associations between the immature platelet fraction, immature platelet count, mean platelet volume, platelet distribution width and platelet large cell ratio (r = 0.61-0.99, p<0.0001. Thrombopoietin levels were inversely related to all of the platelet turnover parameters (r = -0.17--0.25, p<0.0001. Moreover, thrombopoietin levels were significantly increased in patients with diabetes (p = 0.03 and in smokers (p = 0.003. Low-grade inflammation evaluated by high-sensitive CRP correlated significantly, yet weakly, with immature platelet count (r = 0.10, p = 0.03 and thrombopoietin (r = 0.16, p<0.001. Also interleukin-6 correlated with thrombopoietin (r = 0.10, p = 0.02. CONCLUSION: In stable CAD patients, thrombopoietin was inversely associated with platelet turnover parameters. Furthermore, thrombopoietin levels were increased in patients with diabetes and in smokers. However, low-grade inflammation did not seem to have a

  1. Increase in density and accumulation of serotonin by human aging platelets

    International Nuclear Information System (INIS)

    Mezzano, D.; Aranda, E.; Rodriguez, S.; Foradori, A.; Lira, P.

    1984-01-01

    51 Cr-labeled autologous platelets were infused into splenectomized subjects and the specific radioactivities of high-density (HD) and low-density (LD) platelet subpopulations were determined sequentially in postinfusion samples. These findings confirm previous observations in eusplenic individuals and support the hypothesis that human LD platelets are, on the average, younger than HD platelets. LD platelets contain 33.8 +/- 13.5 ng serotonin (5HT)/10(8) platelets and HD platelets 76.8 +/- 9.5 ng 5HT/10(8) platelets. Sequential measurements of 5HT in PRP platelets were performed during the recovery phase of thrombocytopenia following splenectomy in patients with idiopathic thrombocytopenic purpura (ITP), a condition associated with aging of platelets in circulation. Presplenectomy platelet 5HT was 17.7 ng/10(8) platelets and on days 1, 6, and 12 after surgery it increased to 18.1, 37.8, and 61.0 ng/10(8) platelets. When three healthy volunteers were given aspirin (500 mg/day) for up to 15 days, no significant change in the 5HT content of circulating platelets was observed. The observation that human HD platelets, enriched with older cells, contain more 5HT than LD platelets taken together with the parallel increase in platelet 5HT and age during the recovery from thrombocytopenia in ITP patients and the lack of effect of aspirin on platelet 5HT content, provides initial evidence that human platelets accumulate 5HT during their life-span in circulation

  2. Platelet reactivity changes significantly throughout all trimesters of pregnancy compared with the nonpregnant state: a prospective study.

    LENUS (Irish Health Repository)

    Burke, N

    2013-12-01

    Platelets play an important role in the pathophysiology of uteroplacental disease and platelet reactivity may be an important marker of uteroplacental disease activity. However, platelet reactivity has not been evaluated comprehensively in normal pregnancy. We sought to evaluate platelet reactivity using a number of agonists at defined time points in pregnancy using a novel platelet assay and compare these with a nonpregnant cohort.

  3. Exosomes: novel effectors of human platelet lysate activity

    Directory of Open Access Journals (Sweden)

    E Torreggiani

    2014-09-01

    Full Text Available Despite the popularity of platelet-rich plasma (PRP and platelet lysate (PL in orthopaedic practice, the mechanism of action and the effectiveness of these therapeutic tools are still controversial. So far, the activity of PRP and PL has been associated with different growth factors (GF released during platelet degranulation. This study, for the first time, identifies exosomes, nanosized vesicles released in the extracellular compartment by a number of elements, including platelets, as one of the effectors of PL activity. Exosomes were isolated from human PL by differential ultracentrifugation, and analysed by electron microscopy and Western blotting. Bone marrow stromal cells (MSC treated with three different exosome concentrations (0.6 μg, 5 μg and 50 μg showed a significant, dose-dependent increase in cell proliferation and migration compared to the control. In addition, osteogenic differentiation assays demonstrated that exosome concentration differently affected the ability of MSC to deposit mineralised matrix. Finally, the analysis of exosome protein content revealed a higher amount of basic fibroblast growth factor (bFGF, vascular endothelial growth factor (VEGF, platelet-derived growth factor (PDGF-BB and transforming growth factor beta 1 (TGF-β1 as compared to PL. In regards to RNA content, an enrichment of small RNAs in exosomes as compared to donor platelets has been found. These results suggest that exosomes consistently contribute to PL activity and could represent an advantageous nanodelivery system for cell-free regeneration therapies.

  4. RGS10 Negatively Regulates Platelet Activation and Thrombogenesis.

    Directory of Open Access Journals (Sweden)

    Nicole R Hensch

    Full Text Available Regulators of G protein signaling (RGS proteins act as GTPase activating proteins to negatively regulate G protein-coupled receptor (GPCR signaling. Although several RGS proteins including RGS2, RGS16, RGS10, and RGS18 are expressed in human and mouse platelets, the respective unique function(s of each have not been fully delineated. RGS10 is a member of the D/R12 subfamily of RGS proteins and is expressed in microglia, macrophages, megakaryocytes, and platelets. We used a genetic approach to examine the role(s of RGS10 in platelet activation in vitro and hemostasis and thrombosis in vivo. GPCR-induced aggregation, secretion, and integrin activation was much more pronounced in platelets from Rgs10-/- mice relative to wild type (WT. Accordingly, these mice had markedly reduced bleeding times and were more susceptible to vascular injury-associated thrombus formation than control mice. These findings suggest a unique, non-redundant role of RGS10 in modulating the hemostatic and thrombotic functions of platelets in mice. RGS10 thus represents a potential therapeutic target to control platelet activity and/or hypercoagulable states.

  5. Chlorogenic Acid Inhibits Human Platelet Activation and Thrombus Formation

    Science.gov (United States)

    Fuentes, Eduardo; Caballero, Julio; Alarcón, Marcelo; Rojas, Armando; Palomo, Iván

    2014-01-01

    Background Chlorogenic acid is a potent phenolic antioxidant. However, its effect on platelet aggregation, a critical factor in arterial thrombosis, remains unclear. Consequently, chlorogenic acid-action mechanisms in preventing platelet activation and thrombus formation were examined. Methods and Results Chlorogenic acid in a dose-dependent manner (0.1 to 1 mmol/L) inhibited platelet secretion and aggregation induced by ADP, collagen, arachidonic acid and TRAP-6, and diminished platelet firm adhesion/aggregation and platelet-leukocyte interactions under flow conditions. At these concentrations chlorogenic acid significantly decreased platelet inflammatory mediators (sP-selectin, sCD40L, CCL5 and IL-1β) and increased intraplatelet cAMP levels/PKA activation. Interestingly, SQ22536 (an adenylate cyclase inhibitor) and ZM241385 (a potent A2A receptor antagonist) attenuated the antiplatelet effect of chlorogenic acid. Chlorogenic acid is compatible to the active site of the adenosine A2A receptor as revealed through molecular modeling. In addition, chlorogenic acid had a significantly lower effect on mouse bleeding time when compared to the same dose of aspirin. Conclusions Antiplatelet and antithrombotic effects of chlorogenic acid are associated with the A2A receptor/adenylate cyclase/cAMP/PKA signaling pathway. PMID:24598787

  6. A radiolabeled antiglobulin test for crossmatching platelet transfusions

    International Nuclear Information System (INIS)

    Kickler, T.S.; Braine, H.G.; Ness, P.M.; Koester, A.; Bias, W.

    1983-01-01

    Despite the use of HLA-matched platelets for alloimmunized recipients, transfusion failures occur. In order to reduce these failures, researchers investigated the use of a radiolabeled antiglobulin technique for platelet crossmatching. The principle of the test is that of an indirect Coombs test using 125 I labeled goat anti-human IgG. Incompatibility is determined by calculating a radioactivity antiglobulin test (RAGT) index. Using this technique, researchers performed 89 crossmatches on 19 leukemic or aplastic patients who were refractory to random donor platelets and receiving varying degrees of HLA-matched platelets. Effectiveness of the transfusion was assessed from the posttransfusion corrected platelet count increment (CCI) determined at 1 and 20 hr. When the RAGT index was 1.9 or less, the mean CCI at 1 lhr was 17,570 +/- 7003/cu mm, n . 55. When the RAGT index was 2.0 or greater, the mean CCI was 4237 +/- 4100/cu mm, n . 34. At 20 hr when the RAGT index was 1.9 or less, the mean CCI was 8722 +/- 3143/cu mm, n . 33, and when the index was 2.0 or greater, the mean CCI was 571 +/- 1286/cu mm, n . 23. Using this technique, one false negative resulted. Nine positive crossmatches with good increments at 1 hr were found; at 20 hr, however, the survival of these units was zero. These data suggest that this method is a useful adjunct in the selection of platelets in the refractory patient

  7. Aluminum induces lipid peroxidation and aggregation of human blood platelets

    Directory of Open Access Journals (Sweden)

    T.J.C. Neiva

    1997-05-01

    Full Text Available Aluminum (Al3+ intoxication is thought to play a major role in the development of Alzheimer's disease and in certain pathologic manifestations arising from long-term hemodialysis. Although the metal does not present redox capacity, it can stimulate tissue lipid peroxidation in animal models. Furthermore, in vitro studies have revealed that the fluoroaluminate complex induces diacylglycerol formation, 43-kDa protein phosphorylation and aggregation. Based on these observations, we postulated that Al3+-induced blood platelet aggregation was mediated by lipid peroxidation. Using chemiluminescence (CL of luminol as an index of total lipid peroxidation capacity, we established a correlation between lipid peroxidation capacity and platelet aggregation. Al3+ (20-100 µM stimulated CL production by human blood platelets as well as their aggregation. Incubation of the platelets with the antioxidants nor-dihydroguaiaretic acid (NDGA (100 µM and n-propyl gallate (NPG (100 µM, inhibitors of the lipoxygenase pathway, completely prevented CL and platelet aggregation. Acetyl salicylic acid (ASA (100 µM, an inhibitor of the cyclooxygenase pathway, was a weaker inhibitor of both events. These findings suggest that Al3+ stimulates lipid peroxidation and the lipoxygenase pathway in human blood platelets thereby causing their aggregation

  8. Platelet activation through a Bi-leaflet mechanical heart valve

    Science.gov (United States)

    Hedayat, Mohammadali; Borazjani, Iman

    2016-11-01

    Platelet activation is one of the major drawbacks of the Mechanical Heart Valves (MHVs) which can increase the risk of thrombus formation in patients. The platelet activation in MHVs can be due to the abnormal shear stress during the systole, the backward leakage flow during the diastole, and the flow through the hinge region. We investigate the contribution of each of the above mechanism to the activation of platelets in MHVs by performing simulations of the flow through the MHV and in the hinge region. The large scale heart valve simulations are performed in a straight aorta using a sharp interface curvilinear immersed boundary method along with a strong-coupling algorithm under physiological flow conditions. In addition, in order to perform the simulation of hinge region the flow field boundary conditions are obtained from the largescale simulations during a whole cardiac cycle. In order to investigate the role of hinge flow on platelet activation in MHVs, a 23mm St. Jude Medical Regent valve hinge with three different gap sizes is tested along with different platelet activation models to ensure the consistency of our results with different activation models. We compare the platelet activation of the hinge region against the bulk of the flow during one cardiac cycle. This work is supported by the American Heart Association Grant 13SDG17220022, and the computational resources were partly provided by Center for Computational Research (CCR) at University at Buffalo.

  9. Synthesis of platelet-activating factor by human blood platelets and leucocytes. Evidence against selective utilization of cellular ether-linked phospholipids

    NARCIS (Netherlands)

    Sturk, A.; Schaap, M. C.; Prins, A.; ten Cate, J. W.; van den Bosch, H.

    1989-01-01

    Synthesis of platelet activating factor (PAF) in blood platelet suspensions may be due to leucocyte contamination. We therefore investigated PAF synthesis in human blood platelet suspensions and granulocyte- (PMN)-enriched leucocyte suspensions upon stimulation by thrombin and Ca2+-ionophore A23187,

  10. An Evaluation of the Accuracy of the Subtraction Method Used for Determining Platelet Counts in Advanced Platelet-Rich Fibrin and Concentrated Growth Factor Preparations

    Directory of Open Access Journals (Sweden)

    Taisuke Watanabe

    2017-01-01

    Full Text Available Platelet concentrates should be quality-assured of purity and identity prior to clinical use. Unlike for the liquid form of platelet-rich plasma, platelet counts cannot be directly determined in solid fibrin clots and are instead calculated by subtracting the counts in other liquid or semi-clotted fractions from those in whole blood samples. Having long suspected the validity of this method, we herein examined the possible loss of platelets in the preparation process. Blood samples collected from healthy male donors were immediately centrifuged for advanced platelet-rich fibrin (A-PRF and concentrated growth factors (CGF according to recommended centrifugal protocols. Blood cells in liquid and semi-clotted fractions were directly counted. Platelets aggregated on clot surfaces were observed by scanning electron microscopy. A higher centrifugal force increased the numbers of platelets and platelet aggregates in the liquid red blood cell fraction and the semi-clotted red thrombus in the presence and absence of the anticoagulant, respectively. Nevertheless, the calculated platelet counts in A-PRF/CGF preparations were much higher than expected, rendering the currently accepted subtraction method inaccurate for determining platelet counts in fibrin clots. To ensure the quality of solid types of platelet concentrates chairside in a timely manner, a simple and accurate platelet-counting method should be developed immediately.

  11. Increased platelet count and leucocyte-platelet complex formation in acute symptomatic compared with asymptomatic severe carotid stenosis.

    LENUS (Irish Health Repository)

    McCabe, D J H

    2005-09-01

    The risk of stroke in patients with recently symptomatic carotid stenosis is considerably higher than in patients with asymptomatic stenosis. In the present study it was hypothesised that excessive platelet activation might partly contribute to this difference.

  12. Can mean platelet component be used as an index of platelet activity in stable coronary artery disease?

    LENUS (Irish Health Repository)

    Cooke, John

    2012-01-31

    Acute coronary syndrome is associated with intracoronary thrombosis secondary to platelet activation. Previous groups have investigated platelet activation in both stable and unstable vascular disease. Most measures of platelet activation are not routinely available or easily adaptable to large scale clinical use. Recently, measurement of the mean platelet component (MPC) has become part of the routine data provided by an automated full blood count analyser, the Advia 120. MPC measures platelet density which changes on platelet activation. Our objectives were to determine if platelet activation, as measured by MPC, is increased in patients with stable coronary artery disease (CAD) and to determine if MPC could be useful in differentiating people with stable CAD from controls on an everyday clinical basis. Three hundred and forty-five consecutive patients attending for elective coronary angiography had full blood count analysis and MPC measurement performed using an ADVIA-120 analyser. Three hundred and twenty-four were analysed in our final dataset. Two hundred and fifty-three (78%) had CAD. Patients with CAD were significantly (p<0.001) older than those without (63.8 versus 56.0 years). Results failed to demonstrate a difference (p=0.467) in MPC between patients with CAD and those with normal coronary arteries (25.8 versus 26.0). Likewise, there was no correlation between MPC and the severity of CAD (Kendall\\'s tau b=-0.086, p=0.04). MPC is not a useful index of platelet activity in stable CAD when used in everyday clinical practice.

  13. Can mean platelet component be used as an index of platelet activity in stable coronary artery disease?

    LENUS (Irish Health Repository)

    Cooke, John

    2009-04-01

    Acute coronary syndrome is associated with intracoronary thrombosis secondary to platelet activation. Previous groups have investigated platelet activation in both stable and unstable vascular disease. Most measures of platelet activation are not routinely available or easily adaptable to large scale clinical use. Recently, measurement of the mean platelet component (MPC) has become part of the routine data provided by an automated full blood count analyser, the Advia 120. MPC measures platelet density which changes on platelet activation. Our objectives were to determine if platelet activation, as measured by MPC, is increased in patients with stable coronary artery disease (CAD) and to determine if MPC could be useful in differentiating people with stable CAD from controls on an everyday clinical basis. Three hundred and forty-five consecutive patients attending for elective coronary angiography had full blood count analysis and MPC measurement performed using an ADVIA-120 analyser. Three hundred and twenty-four were analysed in our final dataset. Two hundred and fifty-three (78%) had CAD. Patients with CAD were significantly (p<0.001) older than those without (63.8 versus 56.0 years). Results failed to demonstrate a difference (p=0.467) in MPC between patients with CAD and those with normal coronary arteries (25.8 versus 26.0). Likewise, there was no correlation between MPC and the severity of CAD (Kendall\\'s tau b=-0.086, p=0.04). MPC is not a useful index of platelet activity in stable CAD when used in everyday clinical practice.

  14. Platelet-rich plasma stimulated by pulse electric fields: Platelet activation, procoagulant markers, growth factor release and cell proliferation.

    Science.gov (United States)

    Frelinger, A L; Torres, A S; Caiafa, A; Morton, C A; Berny-Lang, M A; Gerrits, A J; Carmichael, S L; Neculaes, V B; Michelson, A D

    2016-01-01

    Therapeutic use of activated platelet-rich plasma (PRP) has been explored for wound healing, hemostasis and antimicrobial wound applications. Pulse electric field (PEF) stimulation may provide more consistent platelet activation and avoid complications associated with the addition of bovine thrombin, the current state of the art ex vivo activator of therapeutic PRP. The aim of this study was to compare the ability of PEF, bovine thrombin and thrombin receptor activating peptide (TRAP) to activate human PRP, release growth factors and induce cell proliferation in vitro. Human PRP was prepared in the Harvest SmartPreP2 System and treated with vehicle, PEF, bovine thrombin, TRAP or Triton X-100. Platelet activation and procoagulant markers and microparticle generation were measured by flow cytometry. Released growth factors were measured by ELISA. The releasates were tested for their ability to stimulate proliferation of human epithelial cells in culture. PEF produced more platelet-derived microparticles, P-selectin-positive particles and procoagulant annexin V-positive particles than bovine thrombin or TRAP. These differences were associated with higher levels of released epidermal growth factor after PEF than after bovine thrombin or TRAP but similar levels of platelet-derived, vascular-endothelial, and basic fibroblast growth factors, and platelet factor 4. Supernatant from PEF-treated platelets significantly increased cell proliferation compared to plasma. In conclusion, PEF treatment of fresh PRP results in generation of microparticles, exposure of prothrombotic platelet surfaces, differential release of growth factors compared to bovine thrombin and TRAP and significant cell proliferation. These results, together with PEF's inherent advantages, suggest that PEF may be a superior alternative to bovine thrombin activation of PRP for therapeutic applications.

  15. Glycans and glycosylation of platelets: current concepts and implications for transfusion

    DEFF Research Database (Denmark)

    Sørensen, Anne Louise; Hoffmeister, Karin M; Wandall, Hans H

    2008-01-01

    by the alphaMbeta2 hepatic lectin receptor. Capping the exposed beta-N-acetylglucosamine residues by enzymatic galactosylation restored the circulation of short-term chilled murine platelets, introducing a novel method that allows for cold storage of platelet. Recent studies have, however, shown...... that galactosylation is not sufficient to restore circulation of long-term refrigerated platelets. Additional data indicate that differential carbohydrate-mediated mechanisms may exist for clearance of short-term and long-term cold-stored platelets. SUMMARY: Room temperature storage of platelet products increases...... the risk of transfusion-mediated sepsis and accelerates platelet deterioration, limiting platelet shelf life. Recent evidence suggests that glycoengineering of platelets might allow for their cold storage, significantly improving the quality of platelet products....

  16. Leukocyte-reduction filters and radiation do not cause significant changes in platelet function

    International Nuclear Information System (INIS)

    Nagura, Yutaka; Tsuno, Hirokazu; Shibata, Yoichi; Takahashi, Koki

    2003-01-01

    In the present study, we investigated the effects of radiation and leukocyte-reduction filters on platelet function. Platelet aggregation in response to collagen and ADP were measured prior to and after irradiation and filtration, as were the platelet recovery rate and complement factor C3. Four types of leukocyte-reduction filter were used, namely positively-, negatively-, and non-charged filters (all of polyester composition), as well as a polyurethane filter. Radiation itself did not significantly affect either the platelet recovery rate, platelet function, or C3 value. On the other hand, filtration through polyester leukocyte-reduction filters resulted in a significant reduction in the platelet recovery rate, an effect not observed with the polyurethane filter. However, none of the filters caused significant changes in platelet function or in C3 value. We concluded that radiation and filtration do not cause significant changes in platelet function, but polyurethane filters are superior to polyester filters in relation to platelet recovery. (author)

  17. Inhibition of the plasma SCUBE1, a novel platelet adhesive protein, protects mice against thrombosis.

    Science.gov (United States)

    Wu, Meng-Ying; Lin, Yuh-Charn; Liao, Wei-Ju; Tu, Cheng-Fen; Chen, Ming-Huei; Roffler, Steve R; Yang, Ruey-Bing

    2014-07-01

    Signal peptide-CUB-EGF domain-containing protein 1 (SCUBE1), a secreted and surface-exposed glycoprotein on activated platelets, promotes platelet-platelet interaction and supports platelet-matrix adhesion. Its plasma level is a biomarker of platelet activation in acute thrombotic diseases. However, the exact roles of plasma SCUBE1 in vivo remain undefined. We generated new mutant (Δ) mice lacking the soluble but retaining the membrane-bound form of SCUBE1. Plasma SCUBE1-depleted Δ/Δ mice showed normal hematologic and coagulant features and expression of major platelet receptors, but Δ/Δ platelet-rich plasma showed impaired platelet aggregation in response to ADP and collagen treatment. The addition of purified recombinant SCUBE1 protein restored the aggregation of platelets in Δ/Δ platelet-rich plasma and further enhanced platelet aggregation in +/+ platelet-rich plasma. Plasma deficiency of SCUBE1 diminished arterial thrombosis in mice and protected against lethal thromboembolism induced by collagen-epinephrine treatment. Last, antibodies directed against the epidermal growth factor-like repeats of SCUBE1, which are involved in trans-homophilic protein-protein interactions, protected mice against fatal thromboembolism without causing bleeding in vivo. We conclude that plasma SCUBE1 participates in platelet aggregation by bridging adjacent activated platelets in thrombosis. Blockade of soluble SCUBE1 might represent a novel antithrombotic strategy. © 2014 American Heart Association, Inc.

  18. Functional alterations of human platelets following indium-111 labelling using different incubation media and labelling agents

    International Nuclear Information System (INIS)

    Isaka, Yoshinari; Imaizumi, Masatoshi; Kimura, Kazufumi; Matsumoto, Masayasu; Kamada, Takenobu

    1991-01-01

    Human platelets were labelled in the absence of presence of plasma using 111 In-labelled oxine sulphate, tropolone or 2-mercaptopyridine-N-oxide (MPO). Under in vitro and in vivo conditions, platelet functions were evaluated by measuring their aggregability, survival, recovery and early distribution. High labelling efficiency was achieved in saline labelling, whereas with plasma labelling, it was necessary to concentrate the platelet-rich plasma to 4.8x10 6 platelets/μl. The aggregation of platelets labelled in plasma or saline was compared with that of controls; platelets labelled in saline showed lower aggregability in 2 μM ADP but not in 5 μM ADP nor with collagen. No significant differences in platelet survival and recovery were noted between platelets labelled in plasma and those labelled in saline. Our results indicate that partial loss of ADP aggregability in vitro does not influence the in vivo viability of platelets labelled in saline. Scintigraphic studies showed that platelets labelled in a saline medium were temporarily sequestrated in the liver but not in the spleen or heart. Thus, platelet labelling in saline does not affect platelet function adversely, but platelets labelled in plasma are more desirable for assessing the early distribution of platelets in the reticuloendothelial system. (orig.)

  19. Real-Time Live Confocal Fluorescence Microscopy as a New Tool for Assessing Platelet Vitality.

    Science.gov (United States)

    Hermann, Martin; Nussbaumer, Oliver; Knöfler, Ralf; Hengster, Paul; Nussbaumer, Walter; Streif, Werner

    2010-01-01

    BACKGROUND: Assessment of platelet vitality is important for patients presenting with inherited or acquired disorders of platelet function and for quality assessment of platelet concentrates. METHODS: Herein we combined live stains with intra-vital confocal fluorescence microscopy in order to obtain an imaging method that allows fast and accurate assessment of platelet vitality. Three fluorescent dyes, FITC-coupled wheat germ agglutinin (WGA), tetramethylrhodamine methyl ester perchlorate (TMRM) and acetoxymethylester (Rhod-2), were used to assess platelet morphology, mitochondrial activity and intra-platelet calcium levels. Microscopy was performed with a microlens-enhanced Nipkow spinning disk-based system allowing live confocal imaging. RESULTS: Comparison of ten samples of donor platelets collected before apheresis and platelets collected on days 5 and 7 of storage showed an increase in the percentage of Rhod-2-positive platelets from 3.6 to 47 and finally to 71%. Mitochondrial potential was demonstrated in 95.4% of donor platelets and in 92.5% of platelets stored for 7 days. CONCLUSION: Such fast and accurate visualization of known key parameters of platelet function could be of relevance for studies addressing the quality of platelets after storage and additional manipulation, such as pathogen inactivation, as well as for the analysis of inherited platelet function disorders.

  20. Platelet size and density affect shear-induced thrombus formation in tortuous arterioles

    Science.gov (United States)

    Chesnutt, Jennifer K. W.; Han, Hai-Chao

    2013-10-01

    Thrombosis accounts for 80% of deaths in patients with diabetes mellitus. Diabetic patients demonstrate tortuous microvessels and larger than normal platelets. Large platelets are associated with increased platelet activation and thrombosis, but the physical effects of large platelets in the microscale processes of thrombus formation are not clear. Therefore, the objective of this study was to determine the physical effects of mean platelet volume (MPV), mean platelet density (MPD) and vessel tortuosity on platelet activation and thrombus formation in tortuous arterioles. A computational model of the transport, shear-induced activation, collision, adhesion and aggregation of individual platelets was used to simulate platelet interactions and thrombus formation in tortuous arterioles. Our results showed that an increase in MPV resulted in a larger number of activated platelets, though MPD and level of tortuosity made little difference on platelet activation. Platelets with normal MPD yielded the lowest amount of mural thrombus. With platelets of normal MPD, the amount of mural thrombus decreased with increasing level of tortuosity but did not have a simple monotonic relationship with MPV. The physical mechanisms associated with MPV, MPD and arteriole tortuosity play important roles in platelet activation and thrombus formation.

  1. Platelet Kinetics in Idiopathic Thrombocytopenic Purpura Patients Treated with Thrombopoietin Receptor Agonists

    Science.gov (United States)

    Meyer, Oliver; Herzig, Eric; Salama, Abdulgabar

    2012-01-01

    Aim Thrombopoietin receptor agonists (Tpo RA) increase platelet counts in the majority of chronic autoimmune thrombocytopenia (idiopathic thrombocytopenic purpura; ITP) patients. It is unknown whether this treatment may also improve platelet survival (PS) in these patients. Methods In order to determine platelet survival (PS), autologous platelets were labeled with 111In oxine and retransfused in six patients under treatment with Tpo RA (romiplostim n = 3; eltrombopag n = 3). Results Stable platelet counts of greater than 100 × 103/μl were observed in all 6 patients. Platelet survival was decreased in all cases (mean 2.10 days; range 0.13–3.73 days). No correlation was found between platelet count and PS. Similarly, there was no significant relationship between platelet turnover and platelet count. However, a high platelet turnover, exceeding 25 or three times the norm was observed in 2 patients who presented the lowest PS (0.13 or 0.83 days). Two patients had a moderately shortened PS (1.91 or 2.42 days), and, correspondingly, a moderately increased platelet turnover rate (63,072 or 72,872 platelets/μl/day). Conclusion These results indicate that Tpo RA may not only overcompensate platelet destruction in ITP, but may interfere with other mechanisms, which, in some cases, results in a reduced platelet destruction rate. PMID:22896760

  2. Increasing platelet concentration in platelet-rich plasma inhibits anterior cruciate ligament cell function in three-dimensional culture.

    Science.gov (United States)

    Yoshida, Ryu; Cheng, Mingyu; Murray, Martha M

    2014-02-01

    Tissue engineering is one new strategy being developed to treat ACL ruptures. One such approach is bio-enhanced ACL repair, where a suture repair is supplemented with a bio-active scaffold containing platelets. However, the optimal concentration of platelets to stimulate ACL healing is not known. We hypothesized that increasing platelet concentrations in the scaffold would enhance critical cell behaviors. Porcine ACL fibroblasts were obtained from explant culture and suspended in platelet poor plasma (PPP), 1× platelet-rich plasma (PRP), 3× PRP, 5× PRP, or phosphate buffered saline (PBS). The cell suspensions were cultured in a 3D collagen scaffold. Cellular metabolism (MTT assay), apoptosis (TUNEL assay), and gene expression for type I and type III collagen were measured. 1× PRP significantly outperformed 5× PRP in all parameters studied: Type I and III collagen gene expression, apoptosis prevention, and cell metabolism stimulation. ACL fibroblasts cultured with 1× PRP had the highest type I and type III collagen gene expression. 1× PRP and PPP groups had the highest cell metabolism and lowest apoptosis rates. Concentration of platelets had significant effects on the behavior of ACL fibroblasts; thus, it is an important parameter that should be specified in clinical or basic science studies. © 2013 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

  3. Frequency of human platelet antigens in oncohematological patients with thrombocytopenia and the probability of incompatibility to platelet transfusions.

    Science.gov (United States)

    Bianchi, Juliana Vieira Dos Santos; de Azevedo, Maria Regina Andrade; Jens, Eduardo; Nukui, Youko; Chamone, Dalton Alencar Ficher

    2012-01-01

    The objective of this study was to evaluate the frequencies of human platelet antigens in oncohematological patients with thrombocytopenia and to analyze the probability of their incompatibility with platelet transfusions. Platelet antigen genotyping was performed by sequence-specific primer polymerase chain reaction (SSP-PCR) for the HPA-1a, HPA-1b, HPA-2a, HPA-2b, HPA-3a, HPA-3b, HPA-4a, HPA-4b, HPA-5a, HPA-5b; HPA-15a, HPA-15b alleles in 150 patients of the Hematology Service of the Hospital das Clínicas (FMUSP). THE ALLELE FREQUENCIES FOUND WERE: HPA-1a: 0.837; HPA-1b: 0.163; HPA-2a: 0.830; HPA-2b: 0.170; HPA-3a: 0.700; HPA-3b: 0.300; HPA-4a: 1; HPA-4b: 0; HPA-5a: 0.887; HPA-5b: 0.113; HPA-15a: 0.457 and HPA-15b: 0.543. Data from the present study showed that the A allele is more common in the population than the B allele, except for HPA-15. This suggests that patients homozygous for the B allele are more predisposed to present alloimmunization and refractoriness to platelet transfusions by immune causes. Platelet genotyping could be of great value in the diagnosis of alloimmune thrombocytopenia and to provide compatible platelet concentrates for these patients.

  4. Platelet and leukocyte ROS production and lipoperoxidation are associated with high platelet reactivity in Non-ST elevation myocardial infarction (NSTEMI) patients on dual antiplatelet treatment.

    Science.gov (United States)

    Becatti, Matteo; Fiorillo, Claudia; Gori, Anna Maria; Marcucci, Rossella; Paniccia, Rita; Giusti, Betti; Violi, Francesco; Pignatelli, Pasquale; Gensini, Gian Franco; Abbate, Rosanna

    2013-12-01

    High platelet reactivity (HPR) on dual antiplatelet therapy is a risk factor for adverse vascular events in acute coronary syndrome (ACS) patients. Several studies have shown that reactive oxygen species (ROS) may be involved in modulating platelet function. In Non-ST elevation myocardial infarction (NSTEMI) patients (n = 132) undergoing percutaneous coronary intervention (PCI) on dual antiplatelet therapy blood samples were collected within 24 h from 600 mg clopidogrel loading dose. Platelet reactivity was assessed by light transmission aggregometry using 10 μM ADP, 1 mM arachidonic acid (AA) and 2 μg/ml collagen. ROS production and lipoperoxidation of circulating cells were determined. by FACSCanto flow cytometry. In these patients, we investigated: 1) the relationship between the amount of cellular ROS production/lipoperoxidation and platelet reactivity; 2) the association of cellular ROS production with the presence of high platelet reactivity to ADP and arachidonic acid (AA). Significantly higher levels of platelet and leukocyte-derived ROS were detected in 49 dual HPR (with platelet aggregation by AA ≥ 20% and by ADP ≥ 70%) compared to non-HPR patients (n = 49) [Platelet-derived ROS: +142%; Leukocyte-derived ROS: +14%, p ROS and platelet and leukocyte lipoperoxidation remained significantly associated to dual HPR. The significant predictors of ADP, AA, and collagen platelet aggregation at multiple linear regression analysis, after adjusting for age, cardiovascular risk factors, procedural parameter, medications, leukocyte number and MPV, were platelet-, leukocyte-derived ROS and platelet and leukocyte lipoperoxidation (p ROS production by and lipoperoxidation of platelets are strictly correlated to the different pathways of platelet aggregation and that ROS production and lipoperoxidation of platelets and leukocytes are predictors of non responsiveness to dual antiplatelet treatment. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  5. A numerical analysis model for the interpretation of in vivo platelet consumption data.

    Directory of Open Access Journals (Sweden)

    Ted S Strom

    Full Text Available Unlike anemias, most thrombocytopenias cannot be separated into those due to impaired production and those due to accelerated consumption. While rapid clearance of labeled platelets from the bloodstream can be followed in thrombocytopenic individuals, no model exists for quantitatively inferring from autologous or allogeneic platelet consumption data what changes in random consumption, lifespan dependent consumption, and platelet production rate may have caused the thrombocytopenia. Here we describe a numerical analysis model which resolves these issues. The model applies three parameter values (a random consumption rate constant, a lognormally-distributed platelet lifespan, and the standard deviation of the latter to a matrix comprising a series of platelet cohorts which are sequentially produced and fractionally consumed in a series of time intervals. The cohort platelet counts achieved after equilibration of production and consumption both enumerate the population age distribution and sum to the population platelet count. Continued platelet consumption after production is halted then serves to model in vivo platelet consumption data, with consumption rate in the first such interval defining the equilibrium platelet production rate. We use a least squares fitting procedure to find parameter values which best fit observed platelet consumption data obtained in WT and thrombocytopenic WASP(- mice. Equilibrium platelet age distributions are then 'grafted' into the matrix to allow modeling of the consumption of WT platelets in WASP(- recipients, and vice versa. The optimal parameter values obtained indicate that random WT platelet consumption accounts for a larger fraction of platelet turnover than was previously suspected. Platelet WASP deficiency accelerates random consumption, and a trans effect of recipient WASP deficiency contributes to this. Application of the model to clinical data will allow distinctions to be made between thrombocytopenias

  6. Does size matter in platelet production?

    Science.gov (United States)

    Thon, Jonathan N.

    2012-01-01

    Platelet (PLT) production represents the final stage of megakaryocyte (MK) development. During differentiation, bone marrow MKs extend and release long, branched proPLTs into sinusoidal blood vessels, which undergo repeated abscissions to yield circulating PLTs. Circular-prePLTs are dynamic intermediate structures in this sequence that have the capacity to reversibly convert into barbell-proPLTs and may be related to “young PLTs” and “large PLTs” of both inherited and acquired macrothrombocytopenias. Conversion is regulated by the diameter and thickness of the peripheral microtubule coil, and PLTs are capable of enlarging in culture to generate barbell-proPLTs that divide to yield 2 smaller PLT products. Because PLT number and size are inversely proportional, this raises the question: do macrothrombocytopenias represent a failure in the intermediate stages of PLT production? This review aims to bring together and contextualize our current understanding of terminal PLT production against the backdrop of human macrothrombocytopenias to establish how “large PLTs” observed in both conditions are similar, how they are different, and what they can teach us about PLT formation. A better understanding of the cytoskeletal mechanisms that regulate PLT formation and determine PLT size offers the promise of improved therapies for clinical disorders of PLT production and an important source of PLTs for infusion. PMID:22665937

  7. Platelet-rich plasma for osteoarthritis treatment.

    Science.gov (United States)

    Knop, Eduardo; Paula, Luiz Eduardo de; Fuller, Ricardo

    2016-01-01

    We conducted a comprehensive and systematic search of the literature on the use of platelet-rich plasma (PRP) in the treatment of osteoarthritis, using the Medline, Lilacs, Cochrane and SciELO databases, from May 2012 to October 2013. A total of 23 studies were selected, with nine being controlled trials and, of these, seven randomized, which included 725 patients. In this series, the group receiving PRP showed improvement in pain and joint function compared to placebo and hyaluronic acid. The response lasted up to two years and was better in milder cases. However it was found that there is no standardization in the PRP production method, neither in the number, timing, and volume of applications. Furthermore, the populations studied were not clearly described in many studies. Thus, these results should be analyzed with caution, and further studies with more standardized methods would be necessary for a more consistent conclusion about the PRP role in osteoarthritis. Copyright © 2015 Elsevier Editora Ltda. All rights reserved.

  8. CONGESTIVE HEART FAILURE IN DOGS IS ASSOCIATED WITH INCREASED PLATELET LEUKOCYTE AGGREGATION MEASURED BY FLOW CYTOMETRY

    DEFF Research Database (Denmark)

    Tarnow, Inge; Andreasen, Susanne SH; Olsen, Lisbeth Høier

    2010-01-01

    CONGESTIVE HEART FAILURE IN DOGS IS ASSOCIATED WITH ENHANCED PLATELET-LEUKOCYTE AGGREGATES - A MARKER FOR PLATELET ACTIVATION. I Tarnow1, LH Olsen2, SHS Andreasen2, SG Moesgaard2, CE Rasmussen2, AT Kristensen1, T Falk2. 1Departments of Small Animal Clinical Sciences and 2Animal and Veterinary Basic...... binding),monocyte-platelet (MPAs) and neutrophil-platelet aggregates (NPAs) defined as leukocytes positive for CD61 were measured by whole blood flow cytometry asmarkers of platelet activation. For every dog platelet activation was assessed in unstimulated samples, and in response to exogenously added...

  9. A scalable, micropore, platelet rich plasma separation device.

    Science.gov (United States)

    Dickson, Mary Nora; Amar, Levy; Hill, Michael; Schwartz, Joseph; Leonard, Edward F

    2012-12-01

    We have designed a novel, low energy platelet-rich-plasma (PRP) separator capable of producing 50 mL of PRP in 30 min, intended for military and emergency applications. Blood flows over a 3 mm length of sieve at high rates of shear. A plasma-platelet filtrate passes through the sieve's pores while erythrocytes remain. The filtrate is flowed over a second 3 mm length of smaller-pored sieve that withdraws plasma. Bulk blood volume is maintained by returning platelet-free plasma to the erythrocyte pool, enabling a nearly complete multi-pass platelet extraction. The total percentage of platelets extracted is:θ(T)=1-exp (-V(f)(T)Φ(P)/V) where V is the original plasma volume, V ( f )(T) is the total filtered volume, and ϕ ( P ) is platelet passage ratio (filtrate concentration/bulk average concentration) taken to be constant. Maximum θ(T) occurs at maximum V ( f )(T)× ϕ ( P ) Test microsieves, 3 mm long × 3 mm wide, were used. ϕ ( P ) values measured at various filtrate flow rates (20-100 uL/min) and utilizing various filter pore sizes (1.2-3.5 μm), was as high as 150 %. Maximum V ( f )(T)× ϕ ( P ) was achieved utilizing the 3.5 um filters at the highest flow rate, 100 uL/min. Erythrocyte leakages were always below 2,000/uL, far below the allowable limit stipulated by the American Association of Blood Banking. These data imply that a 13.7 cm(2) filter area is sufficient to achieve the target separation of 50 mL of platelet concentrate in 30 min. The filtration cartridge would consist of multiple microporous strips of 3 mm width arranged in parallel so that each element would see the conditions used in the prototype experiments presented here. Other microfiltration schemes suggest no method of scaling to practical levels.

  10. Formed platelet combustor liner construction feasibility, phase A

    Science.gov (United States)

    Hayes, W. A.; Janke, D. E.

    1992-09-01

    Environments generated in high pressure liquid rocket engines impose severe requirements on regeneratively cooled combustor liners. Liners fabricated for use in high chamber pressures using conventional processes suffer from limitations that can impair operational cycle life and can adversely affect wall compatibility. Chamber liners fabricated using formed platelet technology provide an alternative to conventional regeneratively cooled liners (an alternative that has many attractive benefits). A formed platelet liner is made from a stacked assembly of platelets with channel features. The assembly is diffusion bonded into a flat panel and then three-dimensionally formed into a section of a chamber. Platelet technology permits the liner to have very precisely controlled and thin hot gas walls and therefore increased heat transfer efficiency. Further cooling efficiencies can be obtained through enhanced design flexibility. These advantages translate into increased cycle life and enhanced wall compatibility. The increased heat transfer efficiency can alternately be used to increase engine performance or turbopump life as a result of pressure drop reductions within the regeneratively cooled liner. Other benefits can be obtained by varying the materials of construction within the platelet liner to enhance material compatibility with operating environment or with adjoining components. Manufacturing cost savings are an additional benefit of a formed platelet liner. This is because of reduced touch labor and reduced schedule when compared to conventional methods of manufacture. The formed platelet technology is not only compatible with current state-of-the art combustion chamber structural support and manifolding schemes, it is also an enabling technology that allows the use of other high performance and potentially low cost methods of construction for the entire combustion chamber assembly. The contract under which this report is submitted contains three phases: (1) phase

  11. Increased mean platelet volume in type 2 diabetes mellitus

    Directory of Open Access Journals (Sweden)

    Ezgi Coşkun Yenigün

    2014-03-01

    Full Text Available Objective: Platelet functions have important roles in the development of vascular complications in diabetic patients. Platelets with increased volume have increased activity compared to smaller ones; therefore, mean platelet volume (MPV is used as a marker for platelet activity. In the present study, we evaluated MPV in patients with type II diabetes mellitus (DM and its associations with diabetic microvascular and macrovascular complications. Methods: Consecutive type II diabetic patients were screened from outpatient clinic of Internal Medicine Department of Diskapı Yıldırım Beyazıt Education and Researsch Hospital, Ankara, Turkey. A total of 48 patients with type II DM and 30 age and gender matched healthy subjects constituted the study population. For all subjects a complete blood count including MPV, fasting blood glucose level and lipid parameters were studied. In diabetic patients, duration of diabetes and HbA1C level, presence of microvascular and macrovascular complications were noted additively. Mean platelet volume was compared between diabetic patients and healthy counterparents. Then, among diabetic patients, MPV was compared between the ones with and without microvascular and macrovascular complications. Results: Mean platelet volume was found significantly higher in diabetic patients compared to non-diabetic healthy subjects. Diabetic patients with at least one of the microvascular complications had significantly higher MPV than those without microvascular damage.Higher MPV levels have also been shown in diabetics with macrovascular complications compared to the ones without macrovascular disease. Conclusion: Mean platelet volume was found to be higher in type II diabetics and those having any of microvascular or macrovascular diabetic complications.

  12. Correlation between Platelet Gelsolin and Platelet Activation Level in Acute Myocardial Infarction Rats and Intervention Effect of Effective Components of Chuanxiong Rhizome and Red Peony Root

    Directory of Open Access Journals (Sweden)

    Yue Liu

    2013-01-01

    Full Text Available The biological role of platelet gelsolin in platelet activation of acute myocardial infarction is not defined. In order to provide a potential new antiplatelet target for Chinese medicine and to elucidate the contribution of Xiongshao capsule, the effective components of Chuanxiong rhizome and red peony root, in this study, we randomly allocated Sprague Dawley rats to left anterior descending coronary artery ligation or sham surgery and different drug prophylaxis as control. We found that gelsolin is highly expressed in platelet rich plasma and lowly expressed in platelet poor plasma, accompanied by the high platelet activation level in model rats; plasma actin filaments and mean fluorescence intensity (MFI of platelet calcium ion increased and plasma vitamin D binding protein decreased in model rats. Xiongshao capsule could inhibit the gelsolin expression in platelet rich plasma and ischemic heart tissue simultaneously and reduce the level of plasma F-actin and MFI of platelet calcium ion. Our study concludes that platelet gelsolin is an important contributor to platelet activation, and platelet gelsolin inhibition may form a novel target for antiplatelet therapy. Xiongshao capsule may be a promising Chinese medicine drug for antiplatelet and aspirin-like cardioprotection effect.

  13. Human platelet glycoprotein Ia. One component is only expressed on the surface of activated platelets and may be a granule constituent

    International Nuclear Information System (INIS)

    Bienz, D.; Clemetson, K.J.

    1989-01-01

    Glycoprotein Ia (GP Ia) is a relatively minor component of human blood platelets thought to be a receptor involved in collagen-induced platelet activation. However, some difficulties exist with the definition of this glycoprotein. The expression of GP Ia on resting (prostacyclin analogue-treated) and thrombin-activated platelets was compared by surface labeling with 125 I-lactoperoxidase. Intact platelets or platelets solubilized in sodium dodecyl sulfate were labeled with periodate/[ 3 H]NaBH 4 . Analysis on two-dimensional isoelectric focusing/sodium dodecyl sulfate-polyacrylamide gel electrophoresis gels showed that GP Ia is very poorly labeled in resting platelets. After activation a new spot (GP Ia*) appears with the same relative molecular mass as GP Ia under reducing conditions. GP Ia and Ia* can be clearly separated by two-dimensional nonreduced/reduced gel electrophoresis. Therefore, two glycoproteins which have been termed GP Ia exist in platelets with similar molecular weight and pI under reducing conditions. One of these (GP Ia*) is only surface-labeled when platelets are activated, indicating that it is only exposed on the surface of activated platelets. Supernatant from activated platelets contains this glycoprotein as well as other granule components. This glycoprotein is missing in platelets from two patients with collagen-response defects

  14. Platelet Preparations for Use in Facial Rejuvenation and Wound Healing: A Critical Review of Current Literature.

    Science.gov (United States)

    Sclafani, Anthony P; Azzi, James

    2015-08-01

    In facial plastic surgery, the potential for direct delivery of growth factors from platelet preparations has been of particular interest for use in facial rejuvenation, recovery after facial surgery, and wound healing. A literature search was conducted through PubMed for the terms PRP, PRFM, platelet-rich plasma, platelet-rich fibrin matrix, platelet preparations, platelet therapy, growth factors, platelet facial, platelet facial rejuvenation, platelet wound healing, platelet plastic surgery. Articles pertaining to the use of platelet preparations in facial surgery and wound healing in plastic surgery after 2001 were included. Thirteen in vitro studies showed use of platelet-rich plasma (PRP) and platelet-rich fibrin matrix (PRFM) had a significant effect on cellular activity. Twenty-four out of 28 animal studies exhibited favorable results with use of a platelet preparation, including five of six studies that showed enhanced fat graft survival with addition of a platelet preparation. Twenty-three case series and clinical trials were identified, only two of which showed no differences. Twenty-one reported favorable results with use of various platelet preparations. A total of 47 studies used PRP, four studies evaluated Leukocyte-rich PRP, and fourteen studies used PRFM. The vast majority of studies examined show a significant and measurable effect on cellular changes, wound healing, and facial esthetic outcomes with use of platelet preparations, both topical and injectable. One must also consider possible publication bias against null results that may have had an influence on the data that were available for review. However, the preponderance of studies suggests that platelet preparations might represent an as-of-yet untapped adjunct in facial plastic surgery.

  15. Differential Roles of the NADPH-Oxidase 1 and 2 in Platelet Activation and Thrombosis.

    Science.gov (United States)

    Delaney, M Keegan; Kim, Kyungho; Estevez, Brian; Xu, Zheng; Stojanovic-Terpo, Aleksandra; Shen, Bo; Ushio-Fukai, Masuko; Cho, Jaehyung; Du, Xiaoping

    2016-05-01

    Reactive oxygen species (ROS) are known to regulate platelet activation; however, the mechanisms of ROS production during platelet activation remain unclear. Platelets express different isoforms of nicotinamide adenine dinucleotide (phosphate) (NAD(P)H) oxidases (NOXs). Here, we investigated the role of NOX1 and NOX2 in ROS generation and platelet activation using NOX1 and NOX2 knockout mice. NOX1(-/Y) platelets showed selective defects in G-protein-coupled receptor-mediated platelet activation induced by thrombin and thromboxane A2 analog U46619, but were not affected in platelet activation induced by collagen-related peptide, a glycoprotein VI agonist. In contrast, NOX2(-/-) platelets showed potent inhibition of collagen-related peptide-induced platelet activation, and also showed partial inhibition of thrombin-induced platelet activation. Consistently, production of ROS was inhibited in NOX1(-/Y) platelets stimulated with thrombin, but not collagen-related peptide, whereas NOX2(-/-) platelets showed reduced ROS generation induced by collagen-related peptide or thrombin. Reduced ROS generation in NOX1/2-deficient platelets is associated with impaired activation of Syk and phospholipase Cγ2, but minimally affected mitogen-activated protein kinase pathways. Interestingly, laser-induced arterial thrombosis was impaired but the bleeding time was not affected in NOX2(-/-) mice. Wild-type thrombocytopenic mice injected with NOX2(-/-) platelets also showed defective arterial thrombosis, suggesting an important role for platelet NOX2 in thrombosis in vivo but not hemostasis. NOX1 and NOX2 play differential roles in different platelet activation pathways and in thrombosis. ROS generated by these enzymes promotes platelet activation via the Syk/phospholipase Cγ2/calcium signaling pathway. © 2016 American Heart Association, Inc.

  16. Mice lacking the SLAM family member CD84 display unaltered platelet function in hemostasis and thrombosis.

    Directory of Open Access Journals (Sweden)

    Sebastian Hofmann

    Full Text Available Platelets are anuclear cell fragments derived from bone marrow megakaryocytes that safeguard vascular integrity by forming thrombi at sites of vascular injury. Although the early events of thrombus formation--platelet adhesion and aggregation--have been intensively studied, less is known about the mechanisms and receptors that stabilize platelet-platelet interactions once a thrombus has formed. One receptor that has been implicated in this process is the signaling lymphocyte activation molecule (SLAM family member CD84, which can undergo homophilic interactions and becomes phosphorylated upon platelet aggregation.The role of CD84 in platelet physiology and thrombus formation was investigated in CD84-deficient mice.We generated CD84-deficient mice and analyzed their platelets in vitro and in vivo. Cd84(-/- platelets exhibited normal activation and aggregation responses to classical platelet agonists. Furthermore, CD84 deficiency did not affect integrin-mediated clot retraction and spreading of activated platelets on fibrinogen. Notably, also the formation of stable three-dimensional thrombi on collagen-coated surfaces under flow ex vivo was unaltered in the blood of Cd84(-/- mice. In vivo, Cd84(-/- mice exhibited unaltered hemostatic function and arterial thrombus formation.These results show that CD84 is dispensable for thrombus formation and stabilization, indicating that its deficiency may be functionally compensated by other receptors or that it may be important for platelet functions different from platelet-platelet interactions.

  17. Dose-dependent platelet stimulation and inhibition induced by anti-PIA1 IgG

    Energy Technology Data Exchange (ETDEWEB)

    Ryu, T.; Davis, J.M.; Schwartz, K.A. (Michigan State Univ., East Lansing (USA))

    1990-07-01

    The PIA1 antibody produces several clinically distinct and severe thrombocytopenias. Investigations have demonstrated divergent effects on platelet function; prior reports demonstrated inhibition, while a conflicting publication showed platelet activation. We have resolved this conflict using anti-PIA1 IgG produced by a patient with posttransfusion purpura. Relatively low concentrations stimulated platelet aggregation and release of adenosine triphosphate (ATP) whereas high concentrations inhibited platelet function, producing a thrombasthenia-like state. The number of molecules of platelet-associated IgG necessary to initiate aggregation and ATP release (2,086 +/- 556) or produce maximum aggregation (23,420 +/- 3,706) or complete inhibition (63,582 +/- 2654) were measured with a quantitative radiometric assay for bound anti-PIA1. Preincubation of platelets with high concentrations of PIA1 antibody inhibited platelet aggregation with 10 mumol/L adenosine diphosphate and blocked 125I-labeled fibrinogen platelet binding. Platelet activation with nonfibrinogen dependent agonist, 1 U/ml thrombin, was not inhibited by this high concentration of PIA1 IgG. In conclusion, anti-PIAI IgG produces (1) stimulation of platelet aggregation and ATP release that is initiated with 2000 molecules IgG per platelet and is associated with an increase of 125I-fibrinogen binding; (2) conversely, inhibition of platelet aggregation is observed with maximum antibody binding, 63,000 molecules IgG per platelet, and is mediated via a blockade of fibrinogen binding.

  18. The Dynamics of Platelet Activation during the Progression of Streptococcal Sepsis.

    Directory of Open Access Journals (Sweden)

    Sinead M Hurley

    Full Text Available Platelets contribute to inflammation however, the role of platelet activation during the pathophysiological response to invasive bacterial infection and sepsis is not clear. Herein, we have investigated platelet activation in a mouse model of invasive Streptococcus pyogenes infection at 5, 12, and 18 hours post infection and correlated this to parameters of infection. The platelet population in ex-vivo blood samples showed no increased integrin activation or surface presentation of CD62P, however platelet-neutrophil complex formation and plasma levels of CD62P were increased during bacterial dissemination and the progression of sepsis, indicating that platelet activation had occurred in vivo. Platelet-neutrophil complex formation was the most discriminatory marker of platelet activation. Platelet-neutrophil complexes were increased above baseline levels during early sepsis but decreased to significantly lower levels than baseline during late sepsis. The removal of these complexes from the circulation coincided with a significant increase in organ damage and the accumulation of platelets in the liver sinusoids, suggesting that platelet activation in the circulation precedes accumulation of platelets in damaged organs. The results demonstrate that monitoring platelet activation using complementary methods may provide prognostic information during the pathogenesis of invasive S. pyogenes infection.

  19. Fusaric acid, a mycotoxin, and its influence on blood coagulation and platelet function.

    Science.gov (United States)

    Devaraja, Sannaningaiah; Girish, Kesturu S; Santhosh, Martin S; Hemshekhar, Mahadevappa; Nayaka, Siddaiah C; Kemparaju, Kempaiah

    2013-06-01

    The current study intended to explore the effect of fusaric acid on blood coagulation including plasma coagulation and platelet aggregation. Fusaric acid exhibited biphasic effects on citrated human plasma recalcification time. At concentrations below 50 ng, fusaric acid decreased the clotting time of plasma dose-dependently from 130 ± 3s control value to 32 ± 3s; however, above 50 ng, fusaric acid increased the clotting time from 32 ± 3s and reached a maximum of 152 s at 100 ng and remained unaltered thereafter for the increased dose of fusaric acid. Fusaric acid without damaging red blood cells and platelets, inhibited agonists such as collagen, ADP, thrombin, and epinephrine-induced aggregation of both platelet-rich plasma (PRP) and washed platelets preparations of human. Interestingly, fusaric acid showed biphasic effects only in thrombin-induced platelet aggregation of washed platelets, and at lower concentration (below 900 ng) it activated platelet aggregation; however, in increased concentration (above 900 ng) it inhibited the platelet aggregation of washed platelets. In addition, fusaric acid also inhibited the agonist ADP-induced platelet aggregation of washed platelet suspension but did not show biphasic effect. Further, fusaric acid did not induce the platelets to generate reactive oxygen species (ROS) that clearly suggests that the induction of platelet function could be the result of the fusaric acid-mediated receptor interaction but not through the morphological shape change.

  20. Platelet receptor expression and shedding: glycoprotein Ib-IX-V and glycoprotein VI.

    Science.gov (United States)

    Gardiner, Elizabeth E; Andrews, Robert K

    2014-04-01

    Quantity, quality, and lifespan are 3 important factors in the physiology, pathology, and transfusion of human blood platelets. The aim of this review is to discuss the proteolytic regulation of key platelet-specific receptors, glycoprotein(GP)Ib and GPVI, involved in the function of platelets in hemostasis and thrombosis, and nonimmune or immune thrombocytopenia. The scope of the review encompasses the basic science of platelet receptor shedding, practical aspects related to laboratory analysis of platelet receptor expression/shedding, and clinical implications of using the proteolytic fragments as platelet-specific biomarkers in vivo in terms of platelet function and clearance. These topics can be relevant to platelet transfusion regarding both changes in platelet receptor expression occurring ex vivo during platelet storage and/or clinical use of platelets for transfusion. In this regard, quantitative analysis of platelet receptor profiles on blood samples from individuals could ultimately enable stratification of bleeding risk, discrimination between causes of thrombocytopenia due to impaired production vs enhanced clearance, and monitoring of response to treatment prior to change in platelet count. Copyright © 2014 Elsevier Inc. All rights reserved.

  1. Physiopathology of blood platelets: a model system for studies of cell-to-cell interaction. Comprehensive three year progress report, August 1, 1975--October 31, 1978

    Energy Technology Data Exchange (ETDEWEB)

    Baldini, M.G.

    1978-01-01

    Progress is reported on the following research projects: improved preservation of platelets by freezing; arrest and prevention of hemorrhage in alloimmunized thrombocytopenic patients; in vivo elution of /sup 51/Cr from labeled platelets induced by antibody; platelet age and adhesion to collagen; effect of serotonin on cyclic nucleotides of human platelets; response of cyclic nucleotides to stimulation in stored human platelets; the effect of ..cap alpha..-tocopherol on platelet aggregation; platelet interaction with tumor cells; and studies of platelet membrane fluidity. (HLW)

  2. Glatiramer acetate (copaxone modulates platelet activation and inhibits thrombin-induced calcium influx: possible role of copaxone in targeting platelets during autoimmune neuroinflammation.

    Directory of Open Access Journals (Sweden)

    Sarah C Starossom

    Full Text Available Glatiramer acetate (GA, Copaxone, Copolymer-1 is an FDA approved drug for the treatment of MS and it is very effective in suppressing neuroinflammation in experimental autoimmune encephalitis (EAE, an animal model of MS. Although this drug was designed to inhibit pathogenic T cells, the exact mechanism of EAE/MS suppression by GA is still not well understood. Previously we presented evidence that platelets become activated and promote neuroinflammation in EAE, suggesting a possible pathogenic role of platelets in MS and EAE. We hypothesized that GA could inhibit neuroinflammation by affecting not only immune cells but also platelets.We investigated the effect of GA on the activation of human platelets in vitro: calcium influx, platelet aggregation and expression of activation markers. Our results in human platelets were confirmed by in-vitro and in-vivo studies of modulation of functions of platelets in mouse model. We found that GA inhibited thrombin-induced calcium influx in human and mouse platelets. GA also decreased thrombin-induced CD31, CD62P, CD63, and active form of αIIbβ3 integrin surface expression and formation of platelet aggregates for both mouse and human platelets, and prolonged the bleeding time in mice by 2.7-fold. In addition, we found that GA decreased the extent of macrophage activation induced by co-culture of macrophages with platelets.GA inhibited the activation of platelets, which suggests a new mechanism of GA action in suppression of EAE/MS by targeting platelets and possibly preventing their interaction with immune cells such as macrophages. Furthermore, the reduction in platelet activation by GA may have additional cardiovascular benefits to prevent thrombosis.

  3. Mechanisms of andrographolide-induced platelet apoptosis in human platelets: regulatory roles of the extrinsic apoptotic pathway.

    Science.gov (United States)

    Lien, Li-Ming; Su, Cheng-Chen; Hsu, Wen-Hsien; Lu, Wan-Jung; Chung, Chi-Li; Yen, Ting-Lin; Chiu, Hou-Chang; Sheu, Joen-Rong; Lin, Kuan-Hung

    2013-11-01

    Andrographolide, a novel nuclear factor-κB (NF-κB) inhibitor, is isolated from the leaves of Andrographis paniculata. Platelet activation is relevant to a variety of coronary heart diseases. Our recent studies revealed that andrographolide possesses potent antiplatelet activity by inhibition of the p38 MAPK/(●) HO-NF-κB-ERK2 cascade. Although platelets are anucleated cells, apoptotic machinery apparatus recently has been found to regulate platelet activation and limit platelet lifespan. Therefore, we further investigated the regulatory effects of andrographolide on platelet apoptotic events. In this study, apoptotic signaling events for caspase-3, -8, and Bid were time (10-60 min)- and dose (25-100 μΜ)-dependently activated by andrographolide in human platelets. Andrographolide could also disrupt mitrochondrial membrane potential. In addition, caspase-8 inhibitor (z-IETD-fmk, 50 μΜ) was found to reverse andrographolide-induced caspase-8 activation, whereas the antagonistic anti-Fas receptor (ZB4, 500 ng/mL) and anti-tumor necrosis factor-R1 (H398, 10 µg/mL) monoclonal antibodies did not. In conclusion, this study for the first time demonstrated that andrographolide might limit platelet lifespan by initiating the caspase-8-dependent extrinsic apoptotic pathway, in spite of no direct evidence that death receptors are involved in this process proved. Overall, the various medicinal properties of andrographolide suggest its potential value in treating patients with thromboembolic disorders. Copyright © 2012 John Wiley & Sons, Ltd.

  4. Platelet Counts, MPV and PDW in Culture Proven and Probable Neonatal Sepsis and Association of Platelet Counts with Mortality Rate

    International Nuclear Information System (INIS)

    Ahmad, M. S.; Waheed, A.

    2014-01-01

    Objective: To determine frequency of thrombocytopenia and thrombocytosis, the MPV (mean platelet volume) and PDW (platelet distribution width) in patients with probable and culture proven neonatal sepsis and determine any association between platelet counts and mortality rate. Study Design: Descriptive analytical study. Place and Duration of Study: NICU, Fazle Omar Hospital, from January 2011 to December 2012. Methodology: Cases of culture proven and probable neonatal sepsis, admitted in Fazle Omar Hospital, Rabwah, were included in the study. Platelet counts, MPV and PDW of the cases were recorded. Mortality was documented. Frequencies of thrombocytopenia ( 450000/mm3) were ascertained. Mortality rates in different groups according to platelet counts were calculated and compared by chi-square test to check association. Results: Four hundred and sixty nine patients were included; 68 (14.5%) of them died. One hundred and thirty six (29%) had culture proven sepsis, and 333 (71%) were categorized as probable sepsis. Thrombocytopenia was present in 116 (24.7%), and thrombocytosis was present in 36 (7.7%) cases. Median platelet count was 213.0/mm3. Twenty eight (27.7%) patients with thrombocytopenia, and 40 (12.1%) cases with normal or raised platelet counts died (p < 0.001). Median MPV was 9.30, and median PDW was 12.30. MPV and PDW of the patients who died and who were discharged were not significantly different from each other. Conclusion: Thrombocytopenia is a common complication of neonatal sepsis. Those with thrombocytopenia have higher mortality rate. No significant difference was present between PDW and MPV of the cases who survived and died. (author)

  5. 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.

  6. Renal cells activate the platelet receptor CLEC-2 through podoplanin

    Science.gov (United States)

    Christou, Charita M.; Pearce, Andrew C.; Watson, Aleksandra A.; Mistry, Anita R.; Pollitt, Alice Y.; Fenton-May, Angharad E.; Johnson, Louise A.; Jackson, David G.; Watson, Steve P.; O'Callaghan, Chris A.

    2009-01-01

    We have recently shown that the C-type lectin-like receptor, CLEC-2, is expressed on platelets and that it mediates powerful platelet aggregation by the snake venom toxin, rhodocytin. In addition, we have provided indirect evidence for an endogenous ligand for CLEC-2 in renal cells expressing human immunodeficiency virus type 1 (HIV-1). This putative ligand facilitates transmission of HIV through its incorporation into the viral envelope and binding to CLEC-2 on platelets. The aim of this study was to identify the ligand on these cells which binds to CLEC-2 on platelets. Recombinant CLEC-2 exhibits specific binding to 293T cells in which the HIV can be grown. Further, 293T cells activate both platelets and CLEC-2-transfected DT-40 B cells. The transmembrane protein podoplanin was identified on 293T cells and demonstrated to mediate both binding of 293T cells to CLEC-2 and 293T cell activation of CLEC-2-transfected DT-40 B cells. Podoplanin is expressed on renal cells (podocytes). Further, a direct interaction between CLEC-2 and podoplanin was confirmed using surface plasmon resonance and was shown to be independent of glycosylation of CLEC-2. The interaction has an affinity of 24.5 ± 3.7μM. The present study identifies podoplanin as a ligand for CLEC-2 on renal cells. PMID:18215137

  7. Platelet count in healthy subjects treated with antiplatelet drugs

    Directory of Open Access Journals (Sweden)

    Maczy González-Rincón

    2016-07-01

    Full Text Available Platelet count in peripheral blood of healthy subjects with antiplatelet drugs. 20 subjects were analized. They were distributed in two groups: subject A: 10 who received aspirin (100 mg and B:10 with Clopidogrel (75 mg for 7 days. In all subjects studied platelet count in peripheral blood and PRP. It found a platelet count before treatment with antiplatelet agents in peripheral blood of 258,6 ± 54,46 x 109 l and 7 days after 254 ± 41,86 x 109 l (aspirin and 285,4 ± 70, 196,5 ± 37,90 x 109 l (Clopidogrel respectively. In the PRP of subjects before receiving aspirin was 486,5 ± 129,54 x 109 l and after 449,2 ± 85,51 x 109 l; prior to Clopidogrel ingestion was 565,2 ± 150,41 and 592,9 ± 203,46 x 109 l after treatment. Significant differences were found only for the platelet count in the Clopidogrel Group (p < 0.05. A significant decrease in platelet count was observed in peripheral blood after administration of Clopidogrel, possibly as a result of its pharmacological mechanism. More studies are needed to assess a greater number of individuals and better measure the effect of antiplatelet agents.

  8. Alzheimer disease and platelets: how’s that relevant

    Directory of Open Access Journals (Sweden)

    Catricala Silvia

    2012-09-01

    Full Text Available Abstract Alzheimer Disease (AD is the most common neurodegenerative disorder worldwide, and account for 60% to 70% of all cases of progressive cognitive impairment in elderly patients. At the microscopic level distinctive features of AD are neurons and synapses degeneration, together with extensive amounts of senile plaques and neurofibrillars tangles. The degenerative process probably starts 20–30 years before the clinical onset of the disease. Senile plaques are composed of a central core of amyloid β peptide, Aβ, derived from the metabolism of the larger amyloid precursor protein, APP, which is expressed not only in the brain, but even in non neuronal tissues. More than 30 years ago, some studies reported that human platelets express APP and all the enzymatic activities necessary to process this protein through the same pathways described in the brain. Since then a large number of evidence has been accumulated to suggest that platelets may be a good peripheral model to study the metabolism of APP, and the pathophysiology of the onset of AD. In this review, we will summarize the current knowledge on the involvement of platelets in Alzheimer Disease. Although platelets are generally accepted as a suitable model for AD, the current scientific interest on this model is very high, because many concepts still remain debated and controversial. At the same time, however, these still unsolved divergences mirror a difficulty to establish constant parameters to better defined the role of platelets in AD.

  9. Functional recovery of stored platelets after transfusion.

    Science.gov (United States)

    Bikker, Angela; Bouman, Esther; Sebastian, Silvie; Korporaal, Suzanne J A; Urbanus, Rolf T; Fijnheer, Rob; Boven, Leonie A; Roest, Mark

    2016-05-01

    Platelet (PLT) concentrates are prophylactically given to prevent major bleeding complications. The corrected count increment (CCI) is currently the only tool to monitor PLT transfusion efficacy. PLT function tests cannot be performed in patients with thrombocytopenia. Therefore, an optimized agonist-induced assay was used to determine PLT function, in patients with severe thrombocytopenia before and after transfusion. PLT reactivity toward adenosine diphosphate (ADP), thrombin receptor-activating peptide SFLLRN (TRAP), and convulxin (CVX) was assessed by flow cytometry. P-selectin expression was measured on PLTs from 11 patients with thrombocytopenia before and 1 hour after transfusion, on stored PLTs, and on stored PLTs incubated for 1 hour in whole blood from patients ex vivo. The mean (±SEM) CCI after 1 hour was 11.4 (±1.5). After transfusion, maximal agonist-induced PLT P-selectin expression was on average 29% higher for ADP (p = 0.02), 25% higher for TRAP (p = 0.007), and 24% higher for CVX (p = 0.0008). ADP-induced reactivity of stored PLTs increased with 46% after ex vivo incubation (p = 0.007). These PLTs also showed an overall higher P-selectin expression compared to PLTs 1 hour after transfusion (p = 0.005). After normalization for this background expression, a similar responsiveness was observed. Our study shows recovery of PLT function after transfusion in patients with thrombocytopenia. The majority of functional PLTs measured after transfusion most likely represents stored transfused PLTs that regained functionality in vivo. The difference in baseline P-selectin expression in vivo versus ex vivo suggests a rapid clearance from circulation of PLTs with increased P-selectin expression. © 2016 AABB.

  10. Platelet modulation of human neutrophil functions

    Energy Technology Data Exchange (ETDEWEB)

    McGarrity, S.T.; Hyers, T.M.; Webster, R.O.

    1986-03-01

    The combined presence of platelets (PLTS) and neutrophils (PMN) at inflammatory sites has led to examination of the hypothesis that interaction of these cells modulates their responses to stimuli. Gel-filtered human PLTS (GFP) were found to inhibit N-formyl-met-leu-phe (FMLP) and phorbol myristate acetate (PMA) stimulated PMN O/sub 2//sup -/ generation in a concentration-dependent fashion. The heat-stable inhibitory activity was present in the supernatants of GFP after incubation with FMLP (10/sup -7/M), thrombin (0.5 U/ml) or ADP (20 ..mu..M), suggesting a role for PLT release products. PLT lysates added to PMN produced up to 80% inhibition of O/sub 2//sup -/ generation for PMA and 40% for FMLP. Like GFP, lysates failed to scavenge O/sub 2/..pi.. produced by xanthine oxidase-hypoxanthine. The inhibitory activity could not be ascribed to serotonin or adenosine. PLT lysates failed to compete with /sup 3/H-FMLP for binding to PMN. Sephadex G-200 fractionation of PLT lysates releaved two peaks of inhibitory activity with apparent Mr > 200,000 and < 14,000 Daltons. Pretreatment of PMN with PLT lysates also results in a concentration-dependent inhibition of degranulation provoked by FMLP (2 x 10/sup -7/M) or PMA (2 ng/ml) and PMN chemotaxis to FMLP (10/sup -8/M). These studies indicate that preformed PLT mediator(s) released in response to physiological stimuli may limit tissue damage by PMN at sites of inflammation.

  11. A comprehensive program to minimize platelet outdating.

    Science.gov (United States)

    Fuller, Alice K; Uglik, Kristin M; Braine, Hayden G; King, Karen E

    2011-07-01

    Platelet (PLT) transfusions are essential for patients who are bleeding or have an increased risk of bleeding due to a decreased number or abnormal function of circulating PLTs. A shelf life of 5 days for PLT products presents an inventory management challenge. In 2006, greater than 10% of apheresis PLTs made in the United States outdated. It is imperative to have a sufficient number of products for patients requiring transfusion, but outdating PLTs is a financial burden and a waste of a resource. We present the approach used in our institution to anticipate inventory needs based on current patient census and usage. Strategies to predict usage and to identify changes in anticipated usage are examined. Annual outdating is reviewed for a 10-year period from 2000 through 2009. From January 1, 2000, through December 2009, there were 128,207 PLT transfusions given to 15,265 patients. The methods used to anticipate usage and adjust inventory resulted in an annual outdate rate of approximately 1% for the 10-year period reviewed. In addition we have not faced situations where inventory was inadequate to meet the needs of the patients requiring transfusions. We have identified three elements of our transfusion service that can minimize outdate: a knowledgeable proactive staff dedicated to PLT management, a comprehensive computer-based transfusion history for each patient, and a strong two-way relationship with the primary product supplier. Through our comprehensive program, based on the principles of providing optimal patient care, we have minimized PLT outdating for more than 10 years. © 2011 American Association of Blood Banks.

  12. A prospective cohort study of light transmission platelet aggregometry for bleeding disorders: is testing native platelet-rich plasma non-inferior to testing platelet count adjusted samples?

    Science.gov (United States)

    Castilloux, Jean Francois; Moffat, Karen A; Liu, Yang; Seecharan, Jodi; Pai, Menaka; Hayward, Catherine P M

    2011-10-01

    Light transmission platelet aggregometry (LTA) is important to diagnose bleeding disorders. Experts recommend testing LTA with native (N) rather than platelet count adjusted (A) platelet-rich plasma (PRP), although it is unclear if this provides non-inferior, or superior, detection of bleeding disorders. Our goal was to determine if LTA with NPRP is non-inferior to LTA with APRP for bleeding disorder assessments. A prospective cohort of patients, referred for bleeding disorder testing, and healthy controls, were evaluated by LTA using common agonists, NPRP and APRP (adjusted to 250 x 10⁹ platelets/l). Recruitment continued until 40 controls and 40 patients with definite bleeding disorders were tested. Maximal aggregation (MA) data were assessed for the detection of abnormalities from bleeding disorders (all causes combined to limit bias), using sample-type specific reference intervals. Areas under receiver-operator curves (AUROC) were evaluated using pre-defined criteria (area differences: 0 for superiority). Forty-four controls and 209 patients were evaluated. Chart reviews for 169 patients indicated 67 had bleeding disorders, 28 from inherited platelet secretion defects. Mean MA differences between NPRP and APRP were small for most agonists (ranges, controls: -3.3 to 5.8; patients: -3.0 to 13.7). With both samples, reduced MA with two or more agonists was associated with a bleeding disorder. AUROC differences between NPRP and APRP were small and indicated that NPRP were non-inferior to APRP for detecting bleeding disorders by LTA, whereas APRP met superiority criteria. Our study validates using either NPRP or APRP for LTA assessments of bleeding disorders.

  13. Association study of the platelet collagen receptor glycoprotein VI gene with rheumatoid arthritis

    NARCIS (Netherlands)

    Michou, L.; Cornelis, F.; Baron, M.; Bombardieri, S.; Balsa, A.; Westhovens, R.; Barrera, P.; Alves, H.; Radstake, T.R.D.J.; Migliorini, P.; Bardin, T.; Petit-Teixeira, E.; Boilard, E.

    2013-01-01

    OBJECTIVES: Beyond their role in haemostasis, platelets can actively contribute to immunity. The activation of the platelet collagen receptor glycoprotein VI (GPVI) promotes the release of small extracellular vesicles called microparticles. These microparticles are found in the joint bathing fluid

  14. Platelet cold agglutinins and thrombocytopenia: A diagnostic dilemma in the intensive care unit

    Directory of Open Access Journals (Sweden)

    TV Bharath Kumar

    2014-01-01

    Full Text Available We report a case of pseudo-thrombocytopenia due to cold agglutinins against platelets. These cold agglutinins were the cause for diagnostic confusion and resulted in extensive workup and unnecessary therapeutic precautions. A thirty two year old female with Guillain-Barre syndrome was admitted in the ICU and serial work-up showed markedly low levels of platelets. The patient had no symptoms of bleeding and patient was investigated extensively for deciphering the etiology of low platelet count. In-vitro clumping of platelets was suspected and in-vitro studies showed marked clumping of platelets with ethylene-diamine-tetra-acetic acid, citrate and heparinized samples. The manual platelet count was found to be within normal limits. Thrombocytopenia as a result of platelet cold agglutinins is a rare cause of in-vitro low platelet counts. No clinical problems have been reported due to the same.

  15. The Influence of Low Platelet Count on Whole Blood Aggregometry Assessed by Multiplate

    DEFF Research Database (Denmark)

    Stissing, Trine; Dridi, Nadia P; Ostrowski, Sisse R

    2011-01-01

    in an artificial matrix, platelet-rich plasma (PRP). Heparinized and citrated blood was diluted with autologous plasma to platelet concentrations 200 to 25 × 10(9)/L in WB samples (n = 10) and 200 to 100 × 10(9)/L in PRP samples (n = 7). The platelet aggregation was investigated by the ADP-, ASPI-, COL-, and TRAP......The Multiplate, a whole blood (WB) platelet function test, has shown promising results identifying patients on antiplatelet therapy at increased risk of rethrombosis. In the present study, the influence of low platelet count on platelet aggregation was analyzed and compared with aggregation results......-test. The WB responses decreased at platelet concentration of ≤100 × 10(9)/L (all P platelet concentrations 200 to 100 × 10(9)/L (P

  16. The influence of platelets, plasma and red blood cells on functional haemostatic assays

    DEFF Research Database (Denmark)

    Bochsen, Louise; Johansson, Pär I.; Kristensen, Annemarie Thuri

    2011-01-01

    and combined, influenced the two methodologically different assays, thrombelastography (TEG) and impedance aggregometry (Multiplate). Platelet-rich plasma (200 × 10/l) or pure plasma (0 platelets), with and without added red blood cells (RBCs), hematocrit 0, 0.15 or 0.29, were produced in vitro from platelet...... concentrates, fresh frozen plasma and stored RBC. Pure platelets were investigated by removing plasma components from platelet concentrates by diafiltration against the platelet storage solution Intersol. Plasma was readded by diafiltration against plasma in Intersol. Haemostatic function was evaluated by TEG...... and Multiplate. In the TEG, increasing amounts of RBC reduced clot strength and clot kinetics (α-angle), most markedly in plasma/RBC without platelets. In contrast, RBC in a platelet concentrate matrix enhanced Multiplate aggregation in response to weak agonists (ADP and arachidonic acid). Furthermore, removing...

  17. Platelet-Related Variants Identified by Exomechip Meta-analysis in 157,293 Individuals

    NARCIS (Netherlands)

    Eicher, J.D. (John D.); Chami, N. (Nathalie); T. Kacprowski (Tim); Nomura, A. (Akihiro); M.-H. Chen (Ming-Huei); L.R. Yanek (Lisa); Tajuddin, S.M. (Salman M.); U.M. Schick (Ursula); Slater, A.J. (Andrew J.); V.S. Pankratz (Shane); Polfus, L. (Linda); C. Schurmann (Claudia); Giri, A. (Ayush); J. Brody (Jennifer); L.A. Lange (Leslie); A. Manichaikul (Ani); W.D. Hill (W. David); R. Pazoki (Raha); Elliot, P. (Paul); E. Evangelou (Evangelos); I. Tzoulaki; Gao, H. (He); Vergnaud, A.-C. (Anne-Claire); J. Mathias (Jasmine); D.M. Becker (Diane); L.C. Becker (Lewis); A.D. Burt (Alastair); D.R. Crosslin (David); L.-P. Lyytikäinen (Leo-Pekka); K. Nikus (Kjell); Hernesniemi, J. (Jussi); M. Kähönen (Mika); Raitoharju, E. (Emma); K. Mononen (Kari); O.T. Raitakari (Olli T.); T. Lehtimäki (Terho); M. Cushman (Mary Ann); N.A. Zakai (Neil); D.A. Nickerson (Deborah); Raffield, L.M. (Laura M.); Quarells, R. (Rakale); C.J. Willer (Cristen); G.M. Peloso (Gina); G.R. Abecasis (Gonçalo); D. Liu (Dajiang); P. Deloukas (Panagiotis); N.J. Samani (Nilesh); H. Schunkert (Heribert); J. Erdmann (Jeanette); M. Fornage (Myriam); Richard, M. (Melissa); J.-C. Tardif (Jean-Claude); Rioux, J.D. (John D.); Dube, M.-P. (Marie-Pierre); de Denus, S. (Simon); Y. Lu (Yingchang); E.P. Bottinger (Erwin); R.J.F. Loos (Ruth); A.V. Smith (Albert Vernon); T.B. Harris (Tamara); Launer, L.J. (Lenore J.); V. Gudnason (Vilmundur); Velez Edwards, D.R. (Digna R.); Torstenson, E.S. (Eric S.); Y. Liu (YongMei); R.P. Tracy (Russell); Rotter, J.I. (Jerome I.); S.S. Rich (Stephen); H. Highland (Heather); E.A. Boerwinkle (Eric); Li, J. (Jin); E.M. Lange (Ethan); J.F. Wilson (James); E. Mihailov (Evelin); R. Mägi (Reedik); J.N. Hirschhorn (Joel); A. Metspalu (Andres); T. Esko (Tõnu); Vacchi-Suzzi, C. (Caterina); M.A. Nalls (Michael); A.B. Zonderman; M. Evans (Michele); G. Engström; M. Orho-Melander (Marju); O. Melander (Olle); M.L. O'Donoghue (Michelle L.); D. Waterworth (Dawn); L.C. Wallentin (Lars); White, H.D. (Harvey D.); J. Floyd (James); T.M. Bartz (Traci M.); K.M. Rice (Kenneth); B.M. Psaty (Bruce); J.M. Starr (John); D.C. Liewald (David C.); C. Hayward (Caroline); I.J. Deary (Ian J.); A. Greinacher (Andreas); U. Völker (Uwe); Thiele, T. (Thomas); H. Völzke (Henry); F.J.A. van Rooij (Frank); A.G. Uitterlinden (André); O.H. Franco (Oscar); A. Dehghan (Abbas); T.L. Edwards (Todd L.); S.K. Ganesh (Santhi); S. Kathiresan (Sekar); Faraday, N. (Nauder); P. Auer (Paul); A. Reiner (Alexander); G. Lettre (Guillaume); A.D. Johnson (Andrew)

    2016-01-01

    textabstractPlatelet production, maintenance, and clearance are tightly controlled processes indicative of platelets’ important roles in hemostasis and thrombosis. Platelets are common targets for primary and secondary prevention of several conditions. They are monitored clinically by complete blood

  18. Platelet function in patients with a history of unexplained recurrent miscarriage who subsequently miscarry again.

    LENUS (Irish Health Repository)

    Dempsey, Mark Anthony

    2015-05-01

    This study was designed to evaluate platelet aggregation in pregnant women with a history of unexplained recurrent miscarriage (RM) and to compare platelet function in such patients who go on to have either another subsequent miscarriage or a successful pregnancy.

  19. Proliferation-promoting effect of platelet-rich plasma on human adipose-derived stem cells and human dermal fibroblasts.

    Science.gov (United States)

    Kakudo, Natsuko; Minakata, Tatsuya; Mitsui, Toshihito; Kushida, Satoshi; Notodihardjo, Frederik Zefanya; Kusumoto, Kenji

    2008-11-01

    This study evaluated changes in platelet-derived growth factor (PDGF)-AB and transforming growth factor (TGF)-beta1 release from platelets by platelet-rich plasma activation, and the proliferation potential of activated platelet-rich plasma and platelet-poor plasma on human adipose-derived stem cells and human dermal fibroblasts. Platelet-rich plasma was prepared using a double-spin method, with the number of platelets counted in each preparation stage. Platelet-rich and platelet-poor plasma were activated with autologous thrombin and calcium chloride, and levels of platelet-released PDGF-AB and TGF-beta1 were determined by enzyme-linked immunosorbent assay. Cells were cultured for 1, 4, or 7 days in serum-free Dulbecco's Modified Eagle Medium supplemented with 5% whole blood plasma, nonactivated platelet-rich plasma, nonactivated platelet-poor plasma, activated platelet-rich plasma, or activated platelet-poor plasma. In parallel, these cells were cultured for 1, 4, or 7 days in serum-free Dulbecco's Modified Eagle Medium supplemented with 1%, 5%, 10%, or 20% activated platelet-rich plasma. The cultured human adipose-derived stem cells and human dermal fibroblasts were assayed for proliferation. Platelet-rich plasma contained approximately 7.9 times as many platelets as whole blood, and its activation was associated with the release of large amounts of PDGF-AB and TGF-beta1. Adding activated platelet-rich or platelet-poor plasma significantly promoted the proliferation of human adipose-derived stem cells and human dermal fibroblasts. Adding 5% activated platelet-rich plasma to the medium maximally promoted cell proliferation, but activated platelet-rich plasma at 20% did not promote it. Platelet-rich plasma can enhance the proliferation of human adipose-derived stem cells and human dermal fibroblasts. These results support clinical platelet-rich plasma application for cell-based, soft-tissue engineering and wound healing.

  20. Comparison of different procedures to prepare platelet-rich plasma for studies of platelet aggregation by light transmission aggregometry.

    Science.gov (United States)

    Femia, Eti Alessandra; Pugliano, Mariateresa; Podda, Gianmarco; Cattaneo, Marco

    2012-01-01

    Light transmission aggregometry (LTA), the gold standard for the study of patients with defects of platelet function, is a poorly standardized technique. The guidelines that have been produced so far are largely based on consensus of experts, due to the absence of studies directly comparing different procedures. Therefore, ad hoc studies are needed to gather scientific evidence on how to choose the most appropriate procedures for LTA measurement. In this study, we aimed at evaluating the most appropriate conditions for preparing samples of platelet-rich plasma (PRP) for studies of platelet aggregation by LTA. Citrate-anticoagulated blood from 32 individuals was centrifuged at 150, 200, 250 or 300×g at room temperature for 10 min. Red blood cells contamination was highest in PRP prepared at 150×g; mean platelet volume (MPV) was lowest in PRP prepared at 300×g. The extent of platelet aggregation measured by LTA was lower and more variable in PRP prepared at 300×g. Therefore, centrifugation of blood at 200×g or 250×g for 10 min appears to be the best condition for preparing PRP for LTA studies.