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  • 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.
21

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.
22

Poremećaj funkcionalnosti fibrinoliznog mehanizma kod bolesnika sa venskom trombozom / Fibrinolytic mechanism disorders in patients withvenous thrombosis

Vučković Biljana 30 October 2014 (has links)
<p>Tromboza danas, u većini razvijenih zemalja, predstavlja vodeći uzrok obolevanja i umiranja. Poslednjih godina veoma aktuelna su istraživanja venskog tromboembolizma, obzirom da je incidenca ovog oboljenja 2/1000 osoba godi&scaron;nje, a njegov razvoj posledica udruženog delovanja vi&scaron;e genetskih i stečenih faktora rizika. &Scaron;to preciznije prepoznavanje i sagledavanje &scaron;to većeg broja ovih faktora osnovni je cilj u borbi, kako protiv prve epizode venske tromboze, tako i protiv recidiva ove bolesti. Brojni faktori rizika već su prepoznati kao sastavne karike patofiziolo&scaron;kog lanca venskog trombotskog procesa, ali je evidentno da otkrića mnogih od njih tek predstoje. Među najaktulenijim istraživanjima na ovom polju nalazi se i ispitivanje uloge poremećaja fibrinoliznog mehanizma u venskoj tromboembolijskoj bolesti. Iako su već pruženi dokazi da suprimirana fibrinolizna aktivnost povećava rizik od nastanka ovog oboljenja, jo&scaron; uvek postoje brojna otvorena pitanja, koja se pre svega odnose na ulogu pojedinačnih činilaca fibrinoliznog mehanizma u venskoj trombozi, kao i na globalnu ulogu fibrinoliznog mehanizma u različitim tipovima i lokalizacijama venske trombotske bolesti. Pored toga, ispitivanje uticaja pojedinih genskih mutacija na pojadinačne činioce fibrinoliznog mehanizma, njegovu globalnu funkcionalnost i posredno na rizik za nastanak venske tromboze, takođe zaokuplja pažnju stručne javnosti, obzirom na nekonzistentnost rezultata dobijenih studijama koje se bave ovom problematikom. Cilj ovoga istraživanja je ispitivanje kako globalne funkcionalnosti fibrinoliznog mehanizma, tako i njegovih pojedinačnih činilaca, kod bolesnika sa različitim tipovima i lokalizacijama venske tromboze i poređenje ovih parametara sa njihovim vrednostima u zdravoj populaciji. Pored toga, cilj istraživanja je i ispitivanje zastupljenosti 4G/5G PAI-1 polimorfizma kod bolesnika sa venskom trombozom u poređenju sa zdravim osobama. Ispitivanu grupu je sačinjavalo 100 bolesnika koji su doživeli trombozu dubokih vena a kontrolnu grupu je činilo 100 zdravih ispitanika, koji nikada nisu imali trombozni incident. Iz ispitivanja su isključene: osobe sa prethodno dokazanim poremećajem hemostaznog mehanizma, osobe koje uzimaju lekove za koje se zna da mogu imati uticaja na hemostazni mehanizam, osobe koje su imale akutnu bolest u momentu uzorkovanja krvi ili 6 nedelja pre toga, osobe sa malignitetom, trudnice, osobe sa težim du&scaron;evnim bolestima, bolestima jetre i bubrega, autoimunim bolestima, ispitanici koji su odbili da potpi&scaron;u pristanak informisanog ispitanika. Kao test za procenu globalne funkcionalnosti fibrinoliznog mehanizma kori&scaron;teno je euglobulinsko vreme lize koaguluma, dok su od pojedinačnih činilaca određivani: tkivni aktivator plazminogena (t-PA) i trombinom aktivi&scaron;ući fibrinolizni inhibitor (TAFI) - ELISA metodom, kao i inhibitor aktivatora plazminogena-1 (PAI-1) - metodom hromogenog substrata. Genetskim ispitivanjem je utvrđivano prisustvo PAI-1 4G/5G genskog polimorfizma. Prema rezultatima istraživanja kod 56% bolesnika bila je prisutna spontana venska tromboza, dok je 44% njih imalo trombozu provociranu jednim od priznatih faktora rizika. U odnosu na lokalizaciju venskog tromboznog procesa proksimalna venska tromboza bila je prisutna kod 63% bolesnika, izolovana distalna venska tromboza kod 29% bolesnika, a atipično lokalizovana venska tromboza kod 8% bolesnika. Posmatrajući zastupljenost pojedinih faktora rizika uočili smo da je značajno vi&scaron;i procenat osoba sa hipertenzijom bio prisutan u grupi bolesnika sa primarnom trombozom dubokih vena u odnosu na grupu bolesnika sa provociranom trombozom dubokih vena (61% vs.16%; p=0.000). &Scaron;to se funkcionalnosti fibrinoliznog mehanizma tiče, prema na&scaron;im rezultatima bolesnici koji su doživeli trombozu dubokih vena imaju značajno duže vreme lize koaguluma, odnosno suprimiranu funkcionalnost fibrinolize u poređenju sa zdravim kontrolama (204.34&plusmn;51.24 vs. 185.62&plusmn;42.30; p=0.011), a kada posmatramo podgrupe bolesnika u odnosu na lokalizaciju i vrstu venske tromboze uočavamo da podgrupa bolesnika sa izolovanom distalnom venskom trombozom ima značajno duže euglobulinsko vreme lize koaguluma u odnosu na kontrolnu grupu (218.32&plusmn;41.12 vs.185.62&plusmn;42.30: p=0.001), kao i bolesnici koji su imali provociranu vensku trombozu u poređenju sa kontrolama (208.18&plusmn;48.53 vs. 185.62&plusmn;42.30; p=0.018). Ispitivanjem pojedinačnih komponenti fibrinoliznog mehanizma do&scaron;li smo do rezultata da bolesnici koji su doživeli venski trombozni incident imaju značajno vi&scaron;e koncentracije TAFI u poređenju sa osobama koje nikada nisu imale vensku trombozu (19.70 ng/ml &plusmn; 5.17 vs.17.13 ng/ml &plusmn; 4.25; p=0.001). Poređenjem bolesnika sa provociranom trombozom dubokih vena i kontrolnih ispitanika uočili smo da bolesnici iz ove podgrupe imaju značajno vi&scaron;e vrednosti plazminogena u poređenju sa zdravim osobama (127.14 % &plusmn; 27.73 vs.117.09 % &plusmn; 24.49; p= 0.044), kao i značajno vi&scaron;e koncentracije t-PA (20.02 ng/ml &plusmn; 11.07 vs. 16.78 ng/ml &plusmn; 8.08; p=0.042). &Scaron;to se tiče TAFI, bolesnici sa distalnom trombozom dubokih vena u poređenju sa kontrolama (20.72 ng/ml &plusmn; 4.96 vs.17.13 ng/ml &plusmn; 4.25; p=0.001), kao i bolesnici sa proksimalnom trombozom dubokih vena u poređenju sa kontrolama (19.37 ng/ml &plusmn; 5.33 vs.17.13 ng/ml &plusmn; 4.25; p=0.013) imaju značajno vi&scaron;e koncentracije TAFI. Koncentracija ovog inhibitora fibrinoliznog procesa značajno je veća i kod bolesnika sa provociranom trombozom dubokih vena u poređenju s zdravim osobama (19.93 ng/ml &plusmn; 3.97 vs.17.13 ng/ml &plusmn; 4.25; p=0.000), kao i kod bolesnika sa primarnom trombozom dubokih vena u poređenju sa zdravim ispitanicima (19.53 ng/ml &plusmn; 5.97 vs.17.13 ng/ml &plusmn; 4.25; p=0.023). &Scaron;to se genetskih analiza tiče, u okviru grupe bolesnika imali smo 25% homozigotnih i 58% heterozigotnih nosilaca mutacije gena za PAI-1, dok 17% bolesnika nije imalo pomenutu gensku mutaciju. U okviru kontrolne grupe pak, bilo je 30% homozigotnih i 56% heterozigotnih nosilaca mutacije a 14% ispitanika nije imalo mutaciju. Nije uočena značajna razlika u zastupljenosti 4G/4G genotipa između bolesnika sa različitim lokalizacijama venskog trombotskog procesa (distalna DVT 29% vs. proksimalna DVT 21% vs. DVT retke lokalizacije 12%; p=0.501), kao ni u zastupljenosti ovoga genotipa kod provocirane i spontane tromboze dubokih vena (27% vs. 23%; p=0.642), niti kod izolovane tromboze dubokih vena u poređenju sa plućnom tromboembolijom (25% vs. 33%; p=0.735). Procena rizika za nastanak venske tromboze u odnosu na postojanje poremećaja globalne funkcionalnosti fibrinoliznog mehanizma, u odnosu na patolo&scaron;ke koncentracije pojedinih komponenti fibrinoliznog mehanizma, kao i u odnosu na postojanje 4G/4G mutacije u genu za PAI-1, pokazala je da suprimirana funkcionalnost fibrinoliznog mehanizma trostruko povećava rizik za nastanak tromboze dubokih vena (OR 3.02; CI 1.26-7.22), povi&scaron;en nivo PAI-1 nema uticaja na rizik od nastanka tromboze dubokih vena, na &scaron;ta ukazuje OR od 0.86 sa CI 0.59-1.25, povi&scaron;en nivo t-PA antigena ne utiče na rizik od nastanka tromboze dubokih vena (OR 1.53; CI 0.79-2.94), ali povi&scaron;ena koncentracija TAFI vi&scaron;e od dvostruko povećava ovaj rizik (OR 2.25; CI 1.16-4.35). Prema na&scaron;im rezultatima PAI-1 4G/4G genotip nema uticaja na rizik od nastanaka venske tromboze, &scaron;to potvrđuje OR koji iznosi 0.57 (0.27-1.20). Na osnovu dobijenih rezultata zaključujemo da bolesnici sa trombozom dubokih vena imaju suprimiranu funkcionalnost fibrinoliznog mehanizma u poređenju sa zdravim osobama, da je nivo t-PA antigena, kao i plazminogena značajno vi&scaron;i kod bolesnika sa provociranom venskom trombozom nego kod zdravih osoba, da nema razlike u koncentraciji PAI-1 između bolesnika sa venskom trombozom i zdravih osoba, ali da bolesnici sa trombozom dubokih vena, bez obzira na njenu lokalizaciju ili vrstu imaju značajno vi&scaron;e nivoe TAFI u poređenju sa zdravim ispitanicima. Pored toga možemo zaključiti da ne postoji razlika u zastupljenosti 4G/5G polimorfizma između bolesnika sa venskom trombozom i zdravih ispitanika. Konačno, možemo reći da na osnovu na&scaron;ih rezultata možemo zaključiti da suprimirana funkcionalnost fibrinoliznog mehanizma trostruko povećava rizik od nastanka tromboze dubokih vena, a povi&scaron;en nivo TAFI-a dvostruko povećava ovaj rizik, dok 4G/5G PAI-1 polimorfizam nema uticaja na rizik za nastanak venskog tromboembolizma.</p> / <p>Thrombosis is nowadays leading cause of morbidity and mortality worldwide. Lately, studies dealing with venous thromboembolism are very actual, since incidence of this disease is 2/1000 persons per year and its development is consequence of joint action of many different inherited and acquired risk factors. Precise recognition and understanding as many of those factors as possible represents imperative in fight against the first episode of venous thrombosis, and also against the recurrence of the disease. Numerous risk factors have been already recognized as constituent links of pathophysiological chain of venous thrombotic process, but it is also clear that the discovery of many of them are yet to come. Investigations of the role of fibrinolytic mechanism disorders in venous thrombosis are topical in the field. Although, we have some evidences that suppressed fibrinolytic activity increases the risk of this disease, still there are many open issues, especially those dealing with the role of individual factors of fibrinolytic mechanism in venous thrombosis, and with the role of global fibrinolytic function in different types and localizations of venous thrombotic disease. Further, investigation of the effects of gene mutations on individual fibrinolytic mechanism components, its global functionality and indirectly to the risk of venous thrombosis, also attracts the attention of experts, given the inconsistency of results obtained from studies dealing with this issue. The aim of this study was to evaluate fibrinolytic mechanism global functionality, as well as functionality of its integral individual components in patients with different venous thrombosis types and localizations, and to compare them with those of the healthy persons. In addition, the aim was to evaluate presence of 4G/5G PAI-1 polymorphism in patients with venous thrombosis compared with healthy subjects. The case group consisted of 100 patients with deep vein thrombosis and the control group consisted of 100 healthy subjects who had never had thrombotic incident. Exclusion criteria were: documented haemostatic disease, taking drugs proven to affect fibrinolytic function, acute illness within 6 weeks before blood sampling, malignancy, pregnancy, severe mental illness, kidney or liver diseases, autoimmune diseases, examinee refusal to sign the informed consent. We used euglobulin cloth lysis time test as test for global fibrinolytic mechanism function estimation, and also determined: t-PA and TAFI concentrations using ELISA method and PAI-1 concentrations using chromogenic substrate method. The presence of PAI-1 4G/5G gene polymorphism was determined by genetic testing. According to results 56% of patients had unprovoked and 44% had provoked venous thrombosis. Proximal venous thrombosis was present in 63% of cases, distal venous thrombosis in 29% of cases and atypical venous thrombosis in 8% of them. Significantly higher frequency of hypertension was present in patients with primary deep vein thrombosis than in the group of patients with provoked deep vein thrombosis (61% vs. 16%, p = 0.000). Patients who have experienced deep vein thrombosis had a significantly longer clot lysis time, and suppressed fibrinolysis function compared with healthy controls (204.34 &plusmn; 51.24 vs. 185.62 &plusmn; 42.30, p = 0.011). Also, this parameter was significantly longer in patients with isolated distal deep vein thrombosis compared with healthy controls (218.32&plusmn;41.12 vs. 185.62&plusmn;42.30: p=0.001), such as in patients with provoked venous thrombosis compared with controls (208.18&plusmn;48.53 vs. 185.62&plusmn;42.30; p=0.018). Patients with venous thrombosis had significantly higher TAFI concentrations in comparison with healthy volunteers (19.70 ng/ml &plusmn; 5.17 vs. 17.13 ng/ml &plusmn; 4.25; p=0.001). Patients with provoked venous thrombosis had significantly higher concentrations of plasminogen (127.14 % &plusmn; 27.73 vs. 117.09 % &plusmn; 24.49; p= 0.044) and t-PA (20.02 ng/ml &plusmn; 11.07 vs. 16.78 ng/ml &plusmn; 8.08; p=0.042), in comparison with controls. Regarding TAFI, we noticed that patients with isolated distal deep vein thrombosis have higher values of this parameter compered with healthy people (20.72 ng/ml &plusmn; 4.96 vs. 17.13 ng/ml &plusmn; 4.25; p=0.001), such as patients with proximal deep vein thrombosis (19.37 ng/ml &plusmn; 5.33 vs. 17.13 ng/ml &plusmn; 4.25; p=0.013). The same was obtained when compared patients with provoked venous thrombosis and controls (19.93 ng/ml &plusmn; 3.97 vs. 17.13 ng/ml &plusmn; 4.25; p=0.000), and patients with unprovoked venous thrombosis and controls (19.53 ng/ml &plusmn; 5.97 vs. 17.13 ng/ml &plusmn; 4.25; p=0.023). As far as genetic analysis, in the group of patients we had 25% homozygous and 58% heterozygous carriers of PAI-1 gene mutation, whereas 17% of patients did&#39;t have this mutation. In controls, we had 30% homozygous and 56% heterozygous carriers of mutation and 14% of those without mutation. There was no significant difference in the frequency of 4G/4G genotype between patients with different localization of venous thrombotic process (distal DVT 29% vs. proximal DVT 21% vs. rare localization DVT 12%, p = 0.501), as well as the representation of this genotype in provoked and unprovoked deep vein thrombosis (27% vs. 23%, p = 0.642), or in isolated deep vein thrombosis compared to pulmonary thromboembolism (25% vs. 33%, p = 0.735). Finaly, our results show that suppressed fibrinolytic functionality threefold increases risk of venous thrombosis (OR 3.02, CI 1.26-7.22), elevated levels of PAI-1 have no effect on the risk of deep vein thrombosis, as evidenced by OR of 0.86 with CI 0.59-1.25, elevated levels of t-PA antigen do not affect the risk of deep venous thrombosis (OR 1.53; CI 0.79-2.94), but increased concentration of TAFI increases more than twice this risk (OR 2.25; CI 1.16-4.35). PAI-1 4G/4G genotype does not affect venous thrombotic risk (OR 0.57; CI 0.27-1.20). Based on these results, we conclude that patients with deep vein thrombosis have suppressed fibrinolytic mechanism functionality compared to healthy subjects, the levels of t-PA antigen and plasminogen are significantly higher in patients with provoked venous thrombosis than in healthy subjects, there is no difference in PAI-1 concentration in patients with venous thrombosis and healthy persons, but the patients with deep vein thrombosis, regardless of its localisation or the type have a significantly higher level of TAFI as compared with healthy subjects. In addition, we can conclude that there is no difference in the prevalence of 4G/5G polymorphism in patients with venous thrombosis and healthy persons. Finally, we can say that suppressed fibrinolytic mechanism functionality threefold increases risk of deep vein thrombosis, elevated level of TAFI-a double increases this risk, while PAI-1 4G/5G polymorphism has no influence on the risk of venous thromboembolism.</p>
23

Genetic aspects of stroke : association and linkage studies in a northern Swedish population

Wiklund, Per-Gunnar January 2005 (has links)
Stroke is a common, multifactorial cardiovascular disease. A stroke event is the result of traditional risk factors (i.e. hypertension, diabetes, smoking), environmental exposures and genetic factors in a complex interplay. The genetic contribution is, as estimated by studies on the influence of family history on the risk of stroke, limited on the individual level, and overridden by, for example the excess risk associated with smoking. On the population level, and as a means to better understand the etiology of stroke, genetics can play a major role. Northern Sweden is well suited for studying the genetic aspects of stroke. The population shows signs of founder effects, and is relatively homogeneous. Large-scale cardiovascular health surveys, the MONICA Project and the Västerbotten Intervention Program, allow studies on risk factors in relation to stroke. Two prospective nested case-referent study samples, (113 cases and 226 controls; 275 cases and 549 controls), and a set of 56 families (117 affected) were collected for functional candidate gene association, and linkage, studies. The selected candidate genes included haemostatic factors and genes within the renin angiotensin system (RAS). Functional single nucleotide polymorphisms (SNPs) that influence the levels of PAI-1 (PAI-1 4G/5G), and tPA (tPA -7,351C&gt;T), have been identified. The angiotensin converting enzyme insertion/deletion polymorphism (ACE I/D) has been shown to be associated with ischaemic stroke. The angiotensin II receptor type 1 A1166C polymorphism (AT1R A1166C), less extensively studied, has been suggested to be associated with stroke, and to interact with the ACE I/D. We found that the PAI-1 4G/4G genotype was associated with an increased risk of future ischaemic stroke (OR 1.79, 95%CI 1.01-3.19), and this was replicated in a second study sample. Furthermore, levels of serum triglycerides modulated the effect of the genotype. In the study on tPA, no association between the tPA -7,351C&gt;T polymorphism and the risk of stroke was found in an analysis of the two study samples pooled. The two RAS polymorphisms were prospectively associated with ischaemic stroke independently of each other and other risk factors (OR 1.60, p=0.02 and OR 1.60, p=0.04, respectively). A candidate region linkage study, focusing on a previously reported stroke susceptibility locus on chromosome 5, was performed in a set of families. In addition, association between ischemic stroke and the positional candidate gene phosphodiesterase 4D (PDE4D) was tested. Linkage to 5q12 was replicated in this independent population, but not PDE4D association with stroke. This suggests that alternative genotypes in this stroke susceptibility locus contribute in different populations. In conclusion, the genetic component in the causation of stroke was investigated. The results of the functional candidate gene association studies showed (1) interaction between PAI-1 genotype and a putatively modifiable risk factor, triglycerides, (2) a prospective testing of the tPA SNP with no association detected, and (3) a novel, hypothesis-generating, finding in the case of AT1R polymorphism and the risk of ischaemic stroke. The replication of linkage to chromosome 5q12 in our northern Swedish population was interesting, and it will be further explored.
24

Análise de um painel de biomarcadores urinários para identificar e prever recidivas de carcinoma urotelial superficial de bexiga / Analysis of panel urinary biomarkers to identify and predict recurrence of superficial bladder urothelial carcinoma

Srougi, Victor 18 January 2019 (has links)
Introdução: O seguimento de pacientes com câncer de bexiga superficial apresenta embargos financeiros e psicológicos ao paciente, devido à realização frequente de exames invasivos. Com fim de substituir ou diminuir os exames invasivos, busca-se biomarcadores urinários acurados, que permitam diagnosticar a recidiva tumoral e estratificar pacientes com maior risco de recidiva futura. O objetivo deste estudo é avaliar se expressão na urina de PAI-1, DJ-1, ApoA-1, MMP-9 e IL-8 permite identificar e antecipar a recidiva de câncer de bexiga. Método: A expressão da PAI-1, DJ-1, ApoA-1, MMP-9 e IL-8 foi mensurada por ELISA na urina de 152 pacientes tratados previamente de carcinoma urotelial superficial de bexiga e em seguimento. Os níveis das proteínas foram comparados entre pacientes com e sem recidiva de câncer de bexiga (1) no momento da coleta de urina e (2) durante o seguimento. A ocorrência de recidiva tumoral foi confirmada por análise histopatológica da biópsia de lesões suspeitas, investigadas quando havia alterações na cistoscopia, ultrassom ou citologia oncótica. Pacientes com recidiva diagnosticada no momento da coleta de urina foram excluídos da análise para avaliar o papel antecipatório das cinco proteínas. Foi avaliado se o uso prévio de BCG intra-vesical exercia influência no nível das cinco proteínas estudadas. Resultados: Entre os pacientes avaliados, 16 (10,5%) apresentaram recidiva de carcinoma urotelial no momento da coleta de urina e 21 (15,4%) apresentaram recidiva de carcinoma urotelial durante o seguimento. O seguimento mediano foi de 47 meses (interquartis de 39 e 50 meses). Um painel para o diagnóstico de recidiva tumoral incluindo três biomarcadores (ApoA-1, MMP-9 e IL-8) apresentou razão de risco de 12,9 (IC 95% =3,5-47,4) e um painel para prever pacientes que desenvolverão recidiva durante o seguimento incluindo dois biomarcadores (PAI-1 e IL-8) apresentou razão de risco de 4,1 (IC 95% =1,4-11,4). Os resultados dos painéis não foram influenciados pelo uso prévio de BCG intra-vesical. Conclusão: Os painéis apresentados permitem identificar pacientes com recidiva de carcinoma urotelial de bexiga e prever quais pacientes terão maior risco de desenvolver recidiva no futuro. O uso prévio de BCG intra-vesical não alterou a expressão dos biomarcadores / Purpose: To evaluate if the urinary levels of PAI-1, DJ-1, ApoA-1, MMP-9 and IL-8 can identify and predict tumor recurrence in patients on follow-up of superficial bladder cancer. Methods: We prospectively analyzed the urine of 152 patients previously treated of superficial bladder cancer on follow-up regimen. Five biomarkers (PAI-1, DJ-1, ApoA-1, MMP-9 and IL-8) were assessed by ELISA and compared among patients with and without bladder cancer recurrence (1) in the moment of urine collection and (2) during follow-up. Tumor recurrence was evaluated with cystoscopy, ultrasound and urine oncotic cytology and confirmed by pathological analysis. Patients with recurrence at urine collection were excluded from prediction analysis. A correlation between the level of the biomarkers and previous use of intravesical BCG was investigated. Results: Median follow-up was 47 months (IQR =39-50 months). Among patients included, 16 (10,5%; N =152) and 21 (15,4%; N =136) had bladder cancer recurrence diagnosed in the moment of urine collection and during follow-up, respectively. The panel to diagnose recurrence including 3 biomarkers (ApoA-1, MMP-9 and IL-8) presented OR =12,9 (CI =3,5-47,4), while the panel to predict patients who will have a recurrence during follow-up including 2 biomarkers (PAI-1 and IL-8) presented OR =4,1 (CI =1,4- 11,4). Previous use of intra-vesical BCG didn\'t influence urine biomarkers expression. Conclusions: The 3-biomarker panel can be used to identify patients with bladder cancer recurrence. The 2-biomarker panel can be used to predict patients at greater risk of bladder cancer recurrence during follow-up. Both are reliable in patients with previous use of intravesical BCG

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