• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 178
  • 40
  • 9
  • 3
  • 2
  • 2
  • 2
  • 1
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 252
  • 68
  • 49
  • 48
  • 38
  • 37
  • 35
  • 32
  • 29
  • 26
  • 26
  • 18
  • 17
  • 17
  • 17
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
71

Evaluation et validation de marqueurs pronostiques et prédictifs dans la prise en charge des patientes présentant un cancer du sein / Evaluation and validation of prognostic and predictive markers of breast cancer

Mazouni, Chafika 02 December 2010 (has links)
L’identification de marqueurs pronostiques et prédictifs du cancer du sein est un facteur important pour une meilleure compréhension du processus évolutif et le développement de thérapies ciblées. Les récepteurs des oestrogènes (RE) représentent ainsi à la fois un marqueur pronostique mais aussi prédictif du traitement par le tamoxifène ou les anti-aromatases. Cependant, un certain nombre de patientes vont évoluer en dépit de traitements anti-hormonaux adaptés. L’objectif de notre travail, a été d’évaluer la méthode de mesure des RE, l’apport des protéases dans la distinction de profils tumoraux pronostiques et prédictifs. Nous avons démontré l’influence du mode de mesure des RE et en particulier de l’expression quantitative sur l’interprétation pronostique et sur une meilleure détermination du bénéfice du traitement en fonction du niveau d’expression des RE. Nous avons montré l’intérêt de l’évaluation des protéases tissulaires uPA, PAI-I et cathépsine-D, pour caractériser l’hétérogénéité des tumeurs en complément des RE. Particulièrement, chez les patientes RE+, des taux élevés de cathépsine-D et de PAI-1 étaient un indicateur de mauvais pronostic. Nous avons développé un nomogramme combinant RE et le statut ganglionnaire à 3 types de protéases : PAI-1, cathépsine-D et la thymidine kinase, pour déterminer la probabilité de survie à 2 et 5 ans. De plus, ces protéases évaluées dans les tumeurs infectées par l’Epstein-Barr virus (EBV), témoignaient de tumeurs biologiquement agressives avec des taux plus élevés de thymidine kinase. Notre travail a contribué à améliorer l’identification de profils des tumeurs en fonction des RE et des protéases et de caractériser les tumeurs viro-induites. / The identification of prognostic and predictive markers is important for a better understanding of the evolutionary process and the development of targeted therapies. Thus estrogen receptors (ER) represent both an important prognostic marker but also predictive of therapies using tamoxifen or aromatase inhibitors. However, a number of patients will evolve despite hormonotherapy. The objective of our work was to evaluate the method for measuring ER, the contribution of proteases in the distinction of prognostic and predictive tumor profiles. In our work, we demonstrated the influence of the mode of measure of ER and in particular its quantitative expression on the prognostic interpretation and a better determination of benefit of treatment depending on the level of expression of ER. We show the interest of the evaluation of tissue proteases uPA, PAI-I and cathepsin-D, to characterize the heterogeneity of tumors in addition to ER. Specifically, in ER + patients, high levels of cathepsin-D and PAI-1 are an indicator of poor prognosis. We developed a nomogram combining ER and nodal status, to 3 types of proteases: PAI-1, cathepsin-D and thymidine kinase, to determine the probability of survival at 2 and 5 years. In addition, these proteases are evaluated in tumors infected with the Epstein-Barr virus (EBV) and shows high rates of thymidine kinase in EBV + BC, reflecting biologically aggressive tumors. Our work has helped to improve the identification of profiles of tumors according to ER and proteases and characterize virus-associated tumors.
72

Programa pai presente como instrumento de efetivação da paternidade socioafetiva

Leandro, Reynaldo Borges Leal 11 December 2017 (has links)
O presente estudo disserta sobre a importância do Programa Pai Presente idealizado pelo Conselho Nacional de Justiça com o objetivo de assegurar ao ser humano o direito fundamental à paternidade, segundo os preceitos da dignidade da pessoa humana que incide sobre as relações familiares. Todavia, as normas do programa que se restringem aos casos de paternidade biológica, destoam-se da nova família constitucional lastreada nos laços de afeto. O aperfeiçoamento normativo do Programa faz-se necessário para alcançar os casos de paternidade socioafetiva identificados durante a execução do projeto, a fim de assegurar aos filhos afetivos os importantes efeitos de ordem jurídica e psicológica, decorrentes do estabelecimento da paternidade, em observância ao princípio da isonomia do estado de filiação. A partir do problema causado pela falta de norma específica, a pesquisa identifica o público alvo do Programa e procura entender os motivos que impossibilitaram o reconhecimento da paternidade biológica nos processos e ao final constata um grande número de casos de paternidade socioafetiva que não tiveram o atendimento jurisdicional adequado. Assim, em razão da relevância do vínculo de afeto como novo critério de fixação da paternidade, propõe-se uma alteração normativa para regulamentar os casos de paternidade socioafetiva no âmbito do Programa Pai Presente. / The present study discusses the importance of the Pai Presente, a program conceived by the National Justice Counsil aiming to assure to human person the fundamental right to paternity according to the precepts of the dignity of the human person that covers family relations. Nonetheless, the norms of the program related to cases of biological paternity disregard the new constitutional concept of family which is derived from ties of affection. Some normative improvement of the Program is necessary to reach out to cases of socio-affective paternity that identified during the implementation of the project, in order to assure to socioaffective children important legal and psychological effects, resulting from the establishment of paternity in compliance with the principle of isonomy of the state of affiliation. Based on the problem caused by the lack of a specific norm, the research identifies the target audience of the Program and seeks to understand the reasons that made it impossible to recognize the biological paternity in the processes and, in the end, finds a large number of cases of socioaffective paternity that did not have the proper jurisdictional care. Thus, considering the relevance of the bond of affection as a new criterion for determining paternity, a normative development is proposed to regulate cases of socioaffective paternity within the scope of the Pai Presente Program.
73

Biochemical and Epidemiological Studies of Early-Onset and Late-Onset Pre-Eclampsia

Wikström, Anna-Karin January 2007 (has links)
<p>Biochemical and epidemiological aspects of pre-eclampsia were investigated, with the main focus on possible pathophysiological differences between early-onset and late-onset disease.</p><p>In pre-eclamptic women poor correlation was found between albumin-creatinine ratio (ACR) in a random urine sample and total amount of albumin in a 24-hour urine collection. <i>(Paper I)</i><b> </b></p><p>In a cohort of women giving birth in Sweden in 1973-82 we estimated the adjusted incidence rate ratio (IRR) for ischaemic heart disease (IHD) during the years 1987–2001. The adjusted IRR for development of IHD was 1.6-2.8 in woman exposed to gestational hypertensive disease during her pregnancy compared with unexposed women. The higher risk represents more severe or recurrent hypertensive disease. <i>(Paper II)</i></p><p>Before delivery, in early-onset pre-eclampsia (24-32 weeks) there were pronounced alterations in plasma concentrations of soluble fms-like tyrosine kinase 1 (sFlt1) and placental growth factor (PlGF), and also a higher placental 8-iso-PGF<sub>2α</sub> concentration and an elevated serum ratio of plasminogen-activator inhibitor (PAI)-1 to PAI-2 compared with early controls. In late-onset pre-eclampsia (35-42 weeks) there were only moderate alterations in sFlt1 and PlGF concentrations, and the placental 8-iso-PGF<sub>2α</sub> concentration and PAI-1/ PAI-2 ratio were similar to those in late controls. <i>(Papers III, V)</i> There was a rapid postpartum decrease in sFlt1 concentration in all groups. One week postpartum the sFlt1 concentration was persistently higher, however, in women with early-onset pre-eclampsia compared with early controls. <i>(Paper IV)</i></p><p>In conclusion: random ACR cannot replace 24-hour urine collections for quantification of albuminuria in pre-eclamptic women; gestational hypertensive disease, especially severe or recurrent, increases the risk for later IHD; early-onset, but not late-onset pre-eclampsia is associated with pronounced alterations of angiogenesis-related markers and only early-onset pre-eclampsia is associated with placental oxidative stress and an increased PAI-1/ PAI-2 ratio, all suggesting a stronger link between early-onset than late-onset pre-eclampsia and a dysfunctional placenta.</p>
74

Biochemical and Epidemiological Studies of Early-Onset and Late-Onset Pre-Eclampsia

Wikström, Anna-Karin January 2007 (has links)
Biochemical and epidemiological aspects of pre-eclampsia were investigated, with the main focus on possible pathophysiological differences between early-onset and late-onset disease. In pre-eclamptic women poor correlation was found between albumin-creatinine ratio (ACR) in a random urine sample and total amount of albumin in a 24-hour urine collection. (Paper I)<b> </b> In a cohort of women giving birth in Sweden in 1973-82 we estimated the adjusted incidence rate ratio (IRR) for ischaemic heart disease (IHD) during the years 1987–2001. The adjusted IRR for development of IHD was 1.6-2.8 in woman exposed to gestational hypertensive disease during her pregnancy compared with unexposed women. The higher risk represents more severe or recurrent hypertensive disease. (Paper II) Before delivery, in early-onset pre-eclampsia (24-32 weeks) there were pronounced alterations in plasma concentrations of soluble fms-like tyrosine kinase 1 (sFlt1) and placental growth factor (PlGF), and also a higher placental 8-iso-PGF2α concentration and an elevated serum ratio of plasminogen-activator inhibitor (PAI)-1 to PAI-2 compared with early controls. In late-onset pre-eclampsia (35-42 weeks) there were only moderate alterations in sFlt1 and PlGF concentrations, and the placental 8-iso-PGF2α concentration and PAI-1/ PAI-2 ratio were similar to those in late controls. (Papers III, V) There was a rapid postpartum decrease in sFlt1 concentration in all groups. One week postpartum the sFlt1 concentration was persistently higher, however, in women with early-onset pre-eclampsia compared with early controls. (Paper IV) In conclusion: random ACR cannot replace 24-hour urine collections for quantification of albuminuria in pre-eclamptic women; gestational hypertensive disease, especially severe or recurrent, increases the risk for later IHD; early-onset, but not late-onset pre-eclampsia is associated with pronounced alterations of angiogenesis-related markers and only early-onset pre-eclampsia is associated with placental oxidative stress and an increased PAI-1/ PAI-2 ratio, all suggesting a stronger link between early-onset than late-onset pre-eclampsia and a dysfunctional placenta.
75

Centre for China Studies

Leung, Hay-lin., 梁喜蓮. January 1994 (has links)
published_or_final_version / Architecture / Master / Master of Architecture
76

The Pai language of Eastern Mpumalanga and its relationship to Swati

Taljaard, Petrus Cornelius 01 1900 (has links)
This thesis is a comparative study of Pai and Swati. The Pai language is spoken in the easten1 parts of the Mpumalanga Province of the Republic of South Africa. The study concentrates on the correspondences and differences of the speech sounds of these two languages and reference is also made to the morphology. The previous comprehensive work on Pai was by Ziervogel (1956) where he classified the Pai language as one of the three dialects of Eastern Sotho. He also considered the Swati elements present in Pai to be merely borrowings. The present investigation into the history of the Pai people indicates that Pai may have had links with languages other than those belonging to the Sotho group and, from the evidence, an Nguni connection has become a distinct possibility. The speech sounds of Pai are described in detail in chapter two and corresponding speech sounds in Swati are included. The vowels of both languages receive special attention because Pai apparently has a seven-vowel system and Swati a five-vowel system. The corresponding consonants in these two languages soon points towards a relationship that is based on more than just borrowed items. In chapter three the Ur-Bantu sounds of Meinhof and their reflexes in Swati and Pai are described and compared. The wide variety of attestations in Pai and the instability of some phonemes are indicative of a language that has been subjected to many outside influences and that is at the moment in a state of flux. In chapter four some aspects of the morphology are described in order to highlight the peculiar characteristics of Pai as an individual language. The relationship with Swati is again emphasized by the findings in this chapter. A statistical analysis of the speech sounds of Pai and Swati in chapter five indicates that an Nguni core of sounds exists that is shared by both these languages. A re-classification of Pai within the language context of that area may therefore be necessary. / African Languages / D. Litt. et Phil. (African Languages)
77

Polimorfismo da região -675 do gene serpine1 (polimorfismo 4g5g) e sua associação com inibidor 1 da ativação do plasminogenio (pai-1), síndrome metabólica e risco cardiovascular em pessoas vivendo com hiv/aids: um estudo caso-controle aninhado à coorte.

OLIVEIRA, Georgge Gomes 27 April 2015 (has links)
Submitted by Irene Nascimento (irene.kessia@ufpe.br) on 2016-12-15T14:53:15Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) VersaoAtualizada2016 - Tese Georgge Gomes Oliveira - varsão para biblioteca UFPE.pdf: 3290385 bytes, checksum: 2ddc23c4486bcc121a9ea222566d1f09 (MD5) / Made available in DSpace on 2016-12-15T14:53:15Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) VersaoAtualizada2016 - Tese Georgge Gomes Oliveira - varsão para biblioteca UFPE.pdf: 3290385 bytes, checksum: 2ddc23c4486bcc121a9ea222566d1f09 (MD5) Previous issue date: 2015-04-27 / Ministério da Saúde do Brasil / Estudos recentes mostram que a síndrome metabólica (SM) é freqüente nas pessoas vivendo com HIV/AIDS (PLWHA). A importância na identificação da SM baseia-se no aumento do risco em cinco vezes de desenvolver diabetes mellitus tipo 2 (DM2) e em duas vezes de apresentar doença cardiovascular (DCV) trombóticas, embora os fatores de hipercoagulabilidade não estejam incluídos nos critérios de definição da síndrome. A SM é caracterizada pela presença concomitante de fatores reconhecidamente aterogênicos em um mesmo indivíduo. A freqüência de DCV em PLWHA vem aumentando ao longo dos anos. O PAI-1 é uma proteína importante na cascata de fibrinólise e seu aumento está associado ao estado de hipercoagulabilidade. Sua regulação depende de fatores genéticos, dentre eles, destaca-se o polimorfismo 4G5G do gene SERPINE1. A participação de substâncias protrombóticas na doença cardiovascular é conhecida em pessoas sem HIV, porém menos elucidada em PLWHA. Diante disto o objetivo deste trabalho foi determinar a freqüência do polimorfismo 4G5G em pessoas que vivem com HIV e verificar se o polimorfismo tem associação com a expressão do PAI-1 plasmático, com SM e com risco cardiovascular (RCV) estimado pelo escore de Framingham. Também objetivamos verificar associação dos níveis de PAI-1 com RDC e com SM. Para tanto foi desenvolvido estudo transversal para determinação da freqüência do polimorfismo 4G5G do PAI-1 e estudo tipo caso-controle para verificar associações entre polimorfismos com níveis plasmáticos de PAI-1 com SM e depois com RCV. Também foram testadas associações com fatores de risco tradicionais. Para primeiro estudo a amostra foi 185 pessoas sorteadas de um grupo de 2074 participantes da Cohort AIDS-PE Study Group. A prevalência de heterozigose foi de 86,8% e homozigose para 4G4G de 4,4%. A média de idade foi de 40,5 (DP ± 9,9 anos). A mediana de PAI-1 ativado foi de 13,6 ng/mL (IQ: 10,8-17,5). A freqüência de SM foi de 37,9% e de dislipidemia de 82,4%. Não encontramos associação do polimorfismo com os níveis plasmáticos de PAI-1, nem com SM. Para o segundo estudo houve perda de 23, restando 162 pessoas das quais 72,8% era do sexo feminino e a média de idade foi de 40 anos. A freqüência de RDCV estimado > 10% foi de 10,5%. O alelo 4G esteve presente em 91,0% das pessoas (genótipos 4G4G e 4G5G). Não houve associação entre polimorfismo e RDCV estimado > 10% (OR=0,6; IC95% 0,1 – 3,7), nem diferença dos níveis de PAI-1 em relação ao RDCV estimado (RCV>10% 14,6 ng/ml x RDCV < 10% 14,1 ng/ml; ρ=0,9). Hipercolesterolemia foi associada com genótipo 5G5G do polimorfismo (OR: 3,3; IC95%: 1,25 – 10) e com níveis plasmáticos mais elevados do PAI-1 (colesterol não HDL (CNHDL) > 130 mg/dl = 15,6 ng/ml versus CNHDL < 130 ng/ml = 13,8 ng/ml; ρ=0,04). Nesse estudo, encontramos alta prevalência do heterozigose para o polimorfismo 4G5G em pessoas vivendo com HIV/AIDS, no nordeste do Brasil. Entretanto, não encontramos associação entre o polimorfismo estudado com níveis plasmáticos de PAI-1 nem com SM. Também não verificamos associação do polimorfismo 4G5G do PAI-1 nem dos níveis plasmáticos de PAI-1 com RCV>10% pelo escore de Framingham, mas houve com hipercolesterolemia. / Recent studies show that the metabolic syndrome (MS) is common in people living with HIV / AIDS (PLWHA). The importance of identifying MS is based on an increased risk of developing fivefold type 2 diabetes mellitus (T2DM) and twice presenting cardiovascular disease (CVD) thrombotic, although hypercoagulability factors are not included in the definition of criteria syndrome. MS is characterized by the concomitant presence of known atherogenic factors in the same individual. The frequency of CVD in PLWHA has increased over the years. The PAI-1 is an important protein in the fibrinolytic cascade and its increase is associated with the hypercoagulable state. Its regulation depends on genetic factors, among them stands out the 4G5G polymorphism SERPINE1 gene. The participation of prothrombotic substances in cardiovascular disease is known in people without HIV, but less elucidated in PLWHA. In view of this the objective of this study was to determine the frequency of 4G5G polymorphism in people living with HIV and verify that polymorphism is associated with the expression of PAI-1 plasma with MS and cardiovascular risk (RCVD) estimated by the Framingham score . We aim to also assess the association of PAI- 1 levels with CVD and with MS. For this cross-sectional study was developed to determine the frequency of 4G5G polymorphism of PAI- 1 and case-control study to examine associations between polymorphisms and plasma levels of PAI- 1 with SM and then RCVD. Associations were also tested with traditional risk factors. For the first study sample was randomly selected 185 people of a group of participants 2074 of AIDS-PE Cohort Study Group. The prevalence of heterozygosity was 86.8% and homozygous for 4G4G 4.4%. The average age was 40.5 (SD ± 9.9 years). The PAI-1 activated median was 13.6 ng/mL (CI: 10.8 to 17.5). The frequency of MS was 37.9% and 82.4% dyslipidemia. We did not find polymorphism association with plasma levels of PAI-1 or with SM. For the second study, there was loss of 23, leaving 162 people of which 72.8% were female and the average age was 40 years. The frequency of RDCV estimated> 10% was 10.5%. The 4G allele was present in 91.0% of people (4G4G and 4G5G genotypes). There was no association between polymorphism and RDCV estimated> 10% (OR = 0.6; 95% CI 0.1 to 3.7), or difference of PAI-1 levels relative to estimated RDCV (RCV> 10% 14.6 ng / ml x RDCV <10% 14.1 ng/ml; ρ = 0.9). Hypercholesterolemia was associated with 5G5G genotype polymorphism (OR: 3.3; 95% CI: 1.25 to 10) and higher plasma levels of PAI-1 (non-HDL cholesterol (CNHDL)> 130 mg / dl = 15.6 ng/ml CNHDL versus <130 ng/ml = 13.8 ng/ ml; ρ = 0.04). In this study, we found a high prevalence of heterozygous for the polymorphism 4G5G in people living with HIV/AIDS, in northeastern Brazil. However, we found no association between the polymorphism studied with plasma levels of PAI-1 or with SM. Nor do we find polymorphism association 4G5G of PAI-1 or plasma levels of PAI-1 with RCV> 10% by Framingham score, but happened to hypercholesterolemia.
78

Le facteur 4 plaquettaire (PF4/CXCL4) prévient la formation du complexe initial de l’inhibiteur de l’activateur du plasminogène (PAI-1) avec sa cible d’origine tissulaire (t-PA) / Platelet factor 4 (PF4/CXCL4) retards formation of the initial complex between plasminogen activator inhibitor 1 (PAI-1) and its target of tissue origin (t-PA)

Libraire, Julie 26 March 2012 (has links)
Le facteur 4 plaquettaire (PF4/CXCL4) est un tétramère constitué de quatre sous-unités identiques de 7,8 kDa qui est libéré en grande quantité par les plaquettes lors de l’hémostase primaire (ensemble des phénomènes permettant un colmatage initial d’une lésion vasculaire). L’étude de la formation d’un caillot de fibrine en présence de PF4 montre une augmentation de la turbidité finale du caillot : le PF4 modifie le réseau formé. Etant donné que la plupart des acteurs de la fibrinolyse se lie au caillot de fibrine et que le PF4 modifie sa structure, nous avons pensé qu’il serait intéressant de rechercher si le PF4 influençait aussi la fibrinolyse. La lyse d'un caillot est effectuée par la plasmine issue de l'activation du plasminogène par son activateur d’origine tissulaire (t-PA) en présence d’un cofacteur qui n'est autre que la fibrine. Nous avons étudié la lyse de caillots de plasma, obtenus par activation de la cascade de la coagulation, en condition statique et à l'aide d'un modèle de thrombose artérielle (système Chandler loop). Dans les deux cas, une diminution du temps de demi-lyse a été observée en présence de PF4. Cependant, la lyse de caillots préparés par simple ajout de thrombine sur du fibrinogène ne permet pas de retrouver cet effet du PF4. Ceci suggère que l’influence du PF4 sur la structure du caillot n’est pas à l’origine de l’effet sur sa lyse et que le PF4 n’influence pas (ou très peu) l'activation du plasminogène, ainsi que l'activité de la plasmine résultante. Cette hypothèse a été confirmée par l’étude de l’activité amydolytique du t-PA et de la plasmine (quelle soit ajoutée ou générée). En système purifié, les inhibiteurs plasmatiques de la fibrinolyse sont absents. Les deux principaux sont l'inhibiteur de l'activateur du plasminogène de type 1 (PAI-1) et l’α2-antiplasmine (α2-AP). La lyse de caillots préparés à partir de plasma déficient en α2-AP montre une diminution du temps de demi-lyse en présence de PF4 (comme pour le plasma normal), alors qu’avec le plasma dépourvu de PAI-1 le temps de demi-lyse n'est plus influencé. De plus, l’ajout de PAI-1 dans le système purifié entraine une diminution du temps de demi-lyse en présence de PF4. Ceci suggère que le PF4 prévient directement ou indirectement l'inhibition du t-PA par PAI-1. L’étude de la cinétique d'inhibition de l’activité amidolytique du t-PA par le PAI-1, la détermination de la stœchiométrie de cette inhibition, et l’analyse de ces cinétiques par immuno-empreinte montrent que le PF4 est un modulateur de la fibrinolyse qui agit en retardant la formation d'un complexe initial entre le t-PA et le PAI-1. Cette nouvelle fonction du PF4 est cohérente, et vient en complément de celle décrite récemment d’inhibiteur de l'activation du TAFI. / Platelet factor 4 (PF4/CXCL4) is a tetramer constituted of four identical 7,8 kDa subunits released in large quantities by platelets during primary heamostasis (allowing initial clogging of a vascular injury). Study of fibrin clot formation in the presence of PF4 shows an increase of the final clot turbidity: PF4 modifies the formed network. Given that most fibrinolysis actors are bound to the fibrin clot and that PF4 modifies its structure we thought it would be interesting to investigate if PF4 also influences fibrinolysis. Clot lysis is performed by plasmin originating from activation of its precursor by tissue plasminogen activator (t-PA) with fibrin itself as cofactor of the reaction. We have studied lysis of plasma clots formed by activation of the coagulation cascade in static condition and in a Chandler loop model mimicking arterial thrombosis. Half-times of lysis decreased in the presence of PF4 in both systems. However, PF4 had no longer detectable influence on the half-time of lysis with clots formed by direct addition of thrombin on purified fibrinogen. Observation suggested that the observed decrease of the half-time of lysis induced by PF4 did not originate from its influence on fibrin clot formation and that PF4 had little effect if any on plasminogen activation or plasmin activity. We confirmed this hypothesis by comparing amydolytic activities of t-PA and plasmin (added or generated through plasminogen activation). In purified system, fibrinolysis inhibitors are absent. The two main inhibitors are plasminogen activator inhibitor-1 (PAI-1) and α2-antiplasmin (α2-AP). Lysis of clots obtained from α2-AP deficient plasma showed a decrease of the half-time of lysis in the presence of PF4 (as in normal plasma), whereas in PAI-1 deficient plasma half-time of lysis was unchanged. Moreover if PAI-1 was added to the purified system, half-time of lysis decreased in the presence of PF4. Observations therefore suggested that PF4 prevented directly or indirectly t-PA inhibition by PAI-1. Kinetics of the amidolytic activity of t-PA inhibition by PAI-1 in the presence or not of PF4, determination of its stoichiometry and Western blot analysis of these inhibition kinetics revealed that PF4 is a fibrinolysis modulator which delays formation of the initial (Michaelis) complex between t-PA and PAI-1. This new feature of PF4 is consistent and complementary with its recently described role as a modulator of TAFI activation.
79

Associations between plasma fatty acids, dietary fatty acids and cardiovascular risk factors : the PURE study / Marilize Richter

Richter, Marilize January 2014 (has links)
Background: Cardiovascular disease (CVD) is the leading global cause of death. CVD risk factors are considered intermediaries for the association between dietary fatty acids and CVD. Raised plasma total cholesterol, low density lipoprotein (LDL) cholesterol, raised triglycerides and decreased levels of high density lipoprotein (HDL) cholesterol, as well as reduced fibrinolytic potential (measured as increased clot lysis time) are known risk factors for CVD. Plasminogen activator inhibitor-1 (PAI-1) is a major inhibitor of the fibrinolytic process and an elevated PAI-1 level is therefore considered to be a potential risk factor for CVD. The growing number of controversies around the role that fat intake (more specifically the type of dietary fat) plays in CVD risk, is making it increasingly difficult for consumers and practitioners alike to form conclusions, and make recommendations and decisions regarding fat intake. Knowledge of the intake of individual fatty acids, fatty acid status (as opposed to subgroups of fat such as polyunsaturated fatty acids) and their associations with blood lipids, PAI-1act and fibrinolytic potential is lacking in black South Africans and other populations. Therefore we aimed to investigate dietary fatty acid intake, as well as plasma phospholipid fatty acid status and their associations with blood lipids, PAI-1act and clot lysis time, as a marker for fibrinolytic potential. Methods: Cross-sectional data analysis within the Prospective Rural Urban Epidemiology (PURE) baseline study of apparently healthy black South African men and women (n=1950, 35– 70 years) from rural and urban areas in the North West Province, from whom dietary data were collected. Blood lipid analyses, as well as laboratory analyses of fibrinolysis markers such as PAI-1act and clot lysis time were also performed. Plasma phospholipid fatty acid extraction and isolation were performed on a random subsample (n = 716). Results: The intake of individual fatty acids was significantly higher in urban than rural dwellers. However, the intake of omega-3 polyunsaturated fatty acids was below recommendations in all groups (rural and urban males, and rural and urban females). Total cholesterol and LDL cholesterol were higher in females than in males, with no rural‒urban differences. Intake of alpha-linolenic acid was positively associated with total cholesterol (β=0.143) and triglycerides (β=0.256) in males. The risk of having elevated LDL cholesterol also increased with increased intake of alpha-linolenic acid (OR 1.49, 95% CI 1.04, 2.14). In females, dietary arachidonic acid and eicosapentaenoic acid (EPA) were positively associated with total cholesterol and LDL cholesterol, whereas docosahexaenoic acid (DHA) was negatively associated with total cholesterol and LDL cholesterol. Dietary alpha-linolenic acid was positively correlated with plasma EPA (males r = 0.19, p = 0.002, females r = 0.25, p < 0.001) and DHA (males r = 0.33, p < 0.001, females r = 0.30, p < 0.001). Plasma DHA was positively associated with triglycerides in males (β = 0.410, p< 0.001) and in females (β = 0.379, p< 0.001). PAI-1act was positively associated with clot lysis time, and plasma myristic acid and DHA were positively associated with PAI-1act in females. However, these fatty acids were not associated with clot lysis time. Different types of plasma fatty acids were associated with PAI-1act than with clot lysis time. Plasma alpha-linolenic acid (β = 0.123, P = 0.037), mead acid (β = 0.176, P = 0.019), arachidonic acid (β = 0.253, 0.025) and omega-3 docosapentaenoic acid (omega-3 DPA) (β = 0.224, P = 0.002) were positively associated with clot lysis time, while both myristic acid (β = - 0.130, P = 0.016) and EPA (β = -0.131, P = 0.021) were negatively associated with clot lysis time in male subjects. Plasma oleic acid (C18:1n9) (β = -0.411, P = 0.001) and omega-6 DPA (C22:5n6) (β = -0.285, P = 0.001) were negatively associated with clot lysis time, while dihomogamma- liolenic acid (DGLA) (C20:3n6) were positively associated (β = 0.178, P = 0.001) with clot lysis time in females. Conclusions: These results suggest that specific individual dietary fatty acids might be associated with blood lipids in males differently than in females, irrespective of rural or urban dwelling. It is not known however, if associations would still be present under conditions of greater intake of alpha-linolenic acid. Our results further suggest that a higher percentage of alpha-linolenic acid might be converted to DHA in this population with low intake of essential and long-chain polyunsaturated fatty acids compared to populations with a high intake of these fatty acids. These results suggest that plasma phospholipid fatty acids should not be used in isolation as biomarkers for intake of fat, without taking dietary intake data into consideration also. Associations between fatty acids and clot lysis time might be independent from PAI-1act. The association between mead acid and clot lysis time indicates that clot lysis time might increase with an essential fatty acid deficiency. This may be of particular concern in this population with a documented lower fat intake. Because the study design of this study is crosssectional, it is not able to determine cause-and-effect, and results should therefore be verified with a randomised controlled trial. / PhD (Nutrition), North-West University, Potchefstroom Campus, 2015
80

Associations between plasma fatty acids, dietary fatty acids and cardiovascular risk factors : the PURE study / Marilize Richter

Richter, Marilize January 2014 (has links)
Background: Cardiovascular disease (CVD) is the leading global cause of death. CVD risk factors are considered intermediaries for the association between dietary fatty acids and CVD. Raised plasma total cholesterol, low density lipoprotein (LDL) cholesterol, raised triglycerides and decreased levels of high density lipoprotein (HDL) cholesterol, as well as reduced fibrinolytic potential (measured as increased clot lysis time) are known risk factors for CVD. Plasminogen activator inhibitor-1 (PAI-1) is a major inhibitor of the fibrinolytic process and an elevated PAI-1 level is therefore considered to be a potential risk factor for CVD. The growing number of controversies around the role that fat intake (more specifically the type of dietary fat) plays in CVD risk, is making it increasingly difficult for consumers and practitioners alike to form conclusions, and make recommendations and decisions regarding fat intake. Knowledge of the intake of individual fatty acids, fatty acid status (as opposed to subgroups of fat such as polyunsaturated fatty acids) and their associations with blood lipids, PAI-1act and fibrinolytic potential is lacking in black South Africans and other populations. Therefore we aimed to investigate dietary fatty acid intake, as well as plasma phospholipid fatty acid status and their associations with blood lipids, PAI-1act and clot lysis time, as a marker for fibrinolytic potential. Methods: Cross-sectional data analysis within the Prospective Rural Urban Epidemiology (PURE) baseline study of apparently healthy black South African men and women (n=1950, 35– 70 years) from rural and urban areas in the North West Province, from whom dietary data were collected. Blood lipid analyses, as well as laboratory analyses of fibrinolysis markers such as PAI-1act and clot lysis time were also performed. Plasma phospholipid fatty acid extraction and isolation were performed on a random subsample (n = 716). Results: The intake of individual fatty acids was significantly higher in urban than rural dwellers. However, the intake of omega-3 polyunsaturated fatty acids was below recommendations in all groups (rural and urban males, and rural and urban females). Total cholesterol and LDL cholesterol were higher in females than in males, with no rural‒urban differences. Intake of alpha-linolenic acid was positively associated with total cholesterol (β=0.143) and triglycerides (β=0.256) in males. The risk of having elevated LDL cholesterol also increased with increased intake of alpha-linolenic acid (OR 1.49, 95% CI 1.04, 2.14). In females, dietary arachidonic acid and eicosapentaenoic acid (EPA) were positively associated with total cholesterol and LDL cholesterol, whereas docosahexaenoic acid (DHA) was negatively associated with total cholesterol and LDL cholesterol. Dietary alpha-linolenic acid was positively correlated with plasma EPA (males r = 0.19, p = 0.002, females r = 0.25, p < 0.001) and DHA (males r = 0.33, p < 0.001, females r = 0.30, p < 0.001). Plasma DHA was positively associated with triglycerides in males (β = 0.410, p< 0.001) and in females (β = 0.379, p< 0.001). PAI-1act was positively associated with clot lysis time, and plasma myristic acid and DHA were positively associated with PAI-1act in females. However, these fatty acids were not associated with clot lysis time. Different types of plasma fatty acids were associated with PAI-1act than with clot lysis time. Plasma alpha-linolenic acid (β = 0.123, P = 0.037), mead acid (β = 0.176, P = 0.019), arachidonic acid (β = 0.253, 0.025) and omega-3 docosapentaenoic acid (omega-3 DPA) (β = 0.224, P = 0.002) were positively associated with clot lysis time, while both myristic acid (β = - 0.130, P = 0.016) and EPA (β = -0.131, P = 0.021) were negatively associated with clot lysis time in male subjects. Plasma oleic acid (C18:1n9) (β = -0.411, P = 0.001) and omega-6 DPA (C22:5n6) (β = -0.285, P = 0.001) were negatively associated with clot lysis time, while dihomogamma- liolenic acid (DGLA) (C20:3n6) were positively associated (β = 0.178, P = 0.001) with clot lysis time in females. Conclusions: These results suggest that specific individual dietary fatty acids might be associated with blood lipids in males differently than in females, irrespective of rural or urban dwelling. It is not known however, if associations would still be present under conditions of greater intake of alpha-linolenic acid. Our results further suggest that a higher percentage of alpha-linolenic acid might be converted to DHA in this population with low intake of essential and long-chain polyunsaturated fatty acids compared to populations with a high intake of these fatty acids. These results suggest that plasma phospholipid fatty acids should not be used in isolation as biomarkers for intake of fat, without taking dietary intake data into consideration also. Associations between fatty acids and clot lysis time might be independent from PAI-1act. The association between mead acid and clot lysis time indicates that clot lysis time might increase with an essential fatty acid deficiency. This may be of particular concern in this population with a documented lower fat intake. Because the study design of this study is crosssectional, it is not able to determine cause-and-effect, and results should therefore be verified with a randomised controlled trial. / PhD (Nutrition), North-West University, Potchefstroom Campus, 2015

Page generated in 0.1342 seconds