130 research outputs found

    Exact intermittent solutions in a turbulence multi branch shell model

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    Reproducing complex phenomena with simple models marks our understanding of the phenomena themselves and this is what Jack Herring's work demonstrated multiple times. In that spirit, this work studies a turbulence shell model consisting of a hierarchy of structures of different scales n\ell_n such that each structure transfers its energy to two substructures of scale n+1=n/λ\ell_{n+1} = \ell_n /\lambda. For this model we construct exact inertial range solutions that display intermittency ie absence of self-similarity. Using a large ensemble of these solutions we investigate how the probability distributions of the velocity modes change with scale. It is demonstrated that while velocity amplitudes are not scale invariant their ratios are. Furthermore using large deviation theory we show how the probability distributions of the velocity modes can be re-scaled to collapse in a scale independent form. Finally, we discuss the implications the present results have for real turbulent flows

    Az új orális antikoagulánsokkal történő kezelés laboratóriumi vonatkozásai | Laboratory aspects of novel oral anticoagulant treatment

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    Absztrakt: Az évtizedek óta várt új orális antikoagulánsok (NOAC) egyre bővülő körben alkalmazott gyógyszerekké váltak a terápiában, hiszen az orális antikoagulánsként korábban egyedüliként alkalmazott kumarinszármazékokhoz képest számos klinikai indikációban a kumarinokkal azonos vagy annál jobb klinikai hatékonyságot mutatnak. Ennek következtében a direkt trombininhibitor dabigatran, majd a direkt X-es alvadási faktort gátló szerek (rivaroxaban, apixaban, edoxaban) az elmúlt években a napi terápiás gyakorlat részévé váltak. Elterjedésüket nem kis részben segítette azon ajánlás, hogy nem igényelnek laboratóriumi monitorizálást, ami mind a beteg, mind a kezelőorvos számára rendkívül nagy előnyt jelent. Az elmúlt évek tapasztalatai azonban bebizonyították, hogy a ‘one size fits all’ szemlélet erősen szimplifikált a NOAC-terápia során, és számos olyan eset van, amikor ezen gyógyszerek koncentrációjának monitorizálása elkerülhetetlen vagy erősen ajánlott. Ez az összefoglaló tanulmány a NOAC-kezelés laboratóriumi vonzatait tárgyalja, kiemelten a hemosztázis alap- és speciális tesztjeire való hatásukat, valamint a korrekt NOAC-koncentráció meghatározására szolgáló laboratóriumi módszereket. Orv Hetil. 2017; 158(49): 1930–1945. | Abstract: The introduction of novel oral anticoagulants (NOAC) have long been expected drugs and they quickly became used widespread as their clinical effectiveness was as good as, or even better than the previously used only oral anticoagulant drug, the coumarins. Thus, the direct thrombin inhibitor dabigatran and the activated factor X inhibitors (rivaroxaban, apixaban, edoxaban) have become the part of daily therapeutic practice. Their permeation was facilitated by the guideline which suggested that no laboratory monitoring was required during NOAC treatment and this was very convenient for both patients and doctors. The clinical experience obtained in the past years, however have proved that the ‘one size fits all’ view is oversimplified and there are numerous situations when the determination NOAC levels is unavoidable or highly recommended. This review discusses the laboratory aspects of NOAC treatment, primarily summarizing their effect on the screening tests and special assays of hemostasis and we also describe the correct methods to determine their plasma concentrations. Orv Hetil. 2017; 158(49): 1930–1945

    Distribution of CFTR mutations in Eastern Hungarians: Relevance to genetic testing and to the introduction of newborn screening for cystic fibrosis

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    AbstractBackgroundThe aim of this study was characterization of an updated distribution of CFTR mutations in a representative cohort of 40 CF patients with the classical form of the disease drawn from Eastern Hungary. Due to the homogeneity of the Hungarian population our data are generally applicable to other regions of the country, including the sizeable diaspora.MethodsWe utilized the recommended “cascade” CFTR mutation screening approach, initially using a commercial assay, followed by examination of the common “Slavic” deletion CFTRdele2,3(21kb). Subsequently, the entire CFTR coding region of the CFTR gene was sequenced in patients with yet unidentified mutations.ResultsThe Elucigene CF29Tm v2 assay detected 81.25% of all CF causing mutations. An addition of the CFTRdele2,3(21kb) increased the mutation detection rate to 86.25%. DNA sequencing enabled us to identify mutations on 79/80 CF alleles. Mutations [CFTRdele2,3(21kb), p.Gln685ThrfsX4 (2184insA) were found at an unusually high frequency, each comprising 5.00% of all CF alleles.ConclusionWe have identified common CF causing mutations in the Hungarian population with the most common mutations (p.Phe508del, p.Asn1303Lys, CFTRdele2,3(21kb), 2184insA, p.Gly542X, and p.Leu101X), comprising over 93.75% of all CF alleles. Obtained data are applicable to the improvement of DNA diagnostics in Hungary and beyond, and are the necessary prerequisite for the introduction of a nationwide “two tier” CF newborn screening program

    A véralvadás XIII-as faktora: strukturális és funkcionális vonatkozások, jelentősége különböző kórképekben = Blood coagulation FXIII: structural, functional aspects, its involvement in various pathological conditions

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    Új megállapításokat tettünk a FXIII plazmában történő aktivációjára, a két alegység (FXIII-A és FXIII-B) egymáshoz kapcsolódásának strukturális elemeire és a FXIIIa-glutamin szubsztrát kapcsolatra vonatkozóan. Új módszereket dolgoztunk ki a FXIII aktivitás mérésére, a FXIII-A intracelluláris detektálására. Utóbbi bevezetésre került a leukémiák diagnosztikájában. Immunoassay-t dolgoztunk ki az a2 plazmin inhibitor két izoformájának mennyiségi meghatározására. 10 FXIII-A hiányos betegen derítettük fel a háttérben álló mutációkat és ezek következményeit a fehérje strukturájára-funkciójára. Kísérletesen bizonyítottuk, hogy a plazma FXIII hiánya sebgyógyulási zavart okoz. Kimutattuk, hogy myocardiális infarctuson (MI) átesett nőkben emelkedett a plasma FXIII szintje és az emelkedett FXIII szint 2,5-3,0 szorosra fokozza az MI rizikóját, ami kizárólag nőkön érvényesül. 16 cikk metaanalízisiével a FXIII-A L34 allél szignifikáns védőhatását lehetett kimutatni a coronaria betegség ellen, a polimorfizmus a nagy rizikóju magyar populációban azonban csak emelkedett fibrinogén szint esetén védő hatású. A L/L homozigóták FXIII szintje MI-ben szignifikánsan alacsonyabb a vad típusúakénál. Csontvelő abláció után csökken, magas thrombocyta számmal járó myeloproliferatív betegségben emelkedik a FXIII szintje. Bronchoalveoláris mosófolyadékban kimutatható az alveoláris macrophagokból származó FXIII-A, chronicus bronchitisben ennek szintje emelkedik, s esetenként megjelenik a plazma FXIII is. | New results were reported on the activation of factor XIII (FXIII) in plasma, on the structural elements involved in the association of FXIII subunits (FXIII-A and FXIII-B) and on the interaction of activated FXIII (FXIIIa) with its glutamine substrate. Methods were developed for the determination of FXIII activity and the intracellular detection of FXIII-A by flow cytometry. The latter was introduced in the diagnostics of leukemias. Immunoassay was developed for the determination of the two isoforms of a2 plasmin inhibitor. The mutations causing FXIII-A deficiency were identified in 10 patients and their consequences were explored at the protein level. The involvement of FXIII in would healing was proven. It was shown that in women with the history of myocardial infarction (MI) FXIII level was elevated and elevated FXIII level represented a 2.5-3.0-fold increased risk of MI in women, but not in men. A protective effect of the FXIII-A L34 allele against MI was demonstrated by metaanalysis of 16 articles. In the Hungarian population this protective effect prevailed only at high fibrinogen level. FXIII level was decreased in L/L homozygotes with the history of MI. Bone marrow ablation decreased plasma FXIII level, while myeloproliferative diseases increased it. In the bronchoalveolar lavage fluid FXIII-A derived from alveolar macrophages was detected, in inflammatory bronchoalveolar diseases FXIII-A level increased and occasionally plasma FXIII was also be present

    Pre-analytical practices for routine coagulation tests in European laboratories. A collaborative study from the European Organisation for External Quality Assurance Providers in Laboratory Medicine (EQALM)

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    Background: Correct handling and storage of blood samples for coagulation tests are important to assure correct diagnosis and monitoring. The aim of this study was to assess the pre-analytical practices for routine coagulation testing in European laboratories. Methods: In 2013–2014, European laboratories were invited to fill in a questionnaire addressing pre-analytical requirements regarding tube fill volume, citrate concentration, sample stability, centrifugation and storage conditions for routine coagulation testing (activated partial thromboplastin time [APTT], prothrombin time in seconds [PT-sec] and as international normalised ratio [PT-INR] and fibrinogen). Results: A total of 662 laboratories from 28 different countries responded. The recommended 3.2% (105–109 mmol/L) citrate tubes are used by 74% of the laboratories. Tube fill volumes ≥90% were required by 73%–76% of the laboratories, depending upon the coagulation test and tube size. The variation in centrifugation force and duration was large (median 2500 g [10- and 90-percentiles 1500 and 4000] and 10 min [5 and 15], respectively). Large variations were also seen in the accepted storage time for different tests and sample materials, for example, for citrated blood at room temperature the accepted storage time ranged from 0.5–72 h and 0.5–189 h for PT-INR and fibrinogen, respectively. If the storage time or the tube fill requirements are not fulfilled, 72% and 84% of the respondents, respectively, would reject the samples. Conclusions: There was a large variation in pre-analytical practices for routine coagulation testing in European laboratories, especially for centrifugation conditions and storage time requirements.publishedVersio

    A neonatal presentation of factor V deficiency: A case report

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    BACKGROUND: Factor V deficiency is a rare autosomal recessive coagulation disorder. Awareness of presenting features and management is important to avoid bleeding complications associated with mortality and neurodisability. CASE PRESENTATION: A 6-day-old Pakistani boy was admitted with bleeding from the left nipple. His parents were first cousins. A coagulation screen showed a prothrombin time of 41 s (control 14 s), a partial thromboplastin time of 132 s (control 33 s) and a normal thrombin time of 15 s (control 14 s). Factor V activity was <0.01 IU/ml. Oral tranexamic acid was started. At 5 weeks of age the child presented with irritability, lethargy and reduced feeding and a drop of hemoglobin to 5.6 g/dl. A cranial computed tomography scan showed a right intra-cerebral bleed extending from the frontal lobe to the parieto-occipital region with shift of the midline to the left. A regime of 20 ml/kg of fresh frozen plasma four times a week was instituted and has prevented further bleeds up to the present age of 21 months. Neurodevelopment remained normal. CONCLUSION: This case illustrates that in an unusually bleeding newborn of consanguineous parents rare severe homozygous bleeding disorders need to be considered. Nipple bleeding may be the first presentation of a congenital bleeding disorder. In cases of factor V deficiency where factor concentrates are not available long term use of fresh frozen plasma can prevent potentially life threatening bleeding

    A véralvadás XIII-as faktora = Blood coagulation factor XIII.

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    I. A XIII-as faktor (FXIII) struktúrája és funkciója Az aktivációs peptid nélkül a FXIII-A instabil. A FXIII aktivációt a plazmában a fibrin polimerizáció determinálja, a FXIII-A Val34Leu polimorfizmusnak csak moduláló hatása van. A FXIII A és B alegységének kapcsolódását gátló monoklonális antitestek előállítása. A celluláris FXIII szerepet játszik a monocyták/macrophagok phagocytosisában. Az alvadékban aktiválódó granulocytákból felszabadult proteázok lebontják a FXIIIa-t. II. Klinikai FXIII kutatások Új típusú módszer a FXIII (ill. más transzglutaminázok) mérésére, ill. a FXIII-A Val34Leu polimorfizmus kimutatására. Az intracelluláris FXIII-A áramlásos citometriás kimutatására új módszer, mely kiválóan alkalmazható az acut myleoid leukemiák diagnosztikájában. Csontvelő abláció során szignifikánsan csökken a plazma FXIII szintje, magas thrombocyta számmal járó myeloproliferatív megbetegedésekben viszont emelkedik. Nőkben az emelkediett FXIII szint több mint kétszeresére növeli a myocardiális infarctus rizikóját nőkben. Krónikus bronchoalveoláris megbetegedésekben jelentősen emelkedik a bronchoalveoláris mosófolyadékban a FXIII mennyisége. 4 új mutációt írtunk le FXIII hiányos betegekben, s analizáltuk ezek fehérje biokémiai következményeit. FXIII hiányíos transzgén egereken igazoltuk, hogy a FXIII szükséges a normális sebgyógyuláshoz. | I. Structure and function of factor XIII (FXIII) The absence of activation peptide makes FXIII-A instable. The activation of FXIII in the plasma is determined by fibrin polymerization; FXIII-A Val34Leu polymorphism only modulates activation. Production of monoclonal antibodies with inhibitory effect on the association of FXIII A and B subunits. Cellular FXIII plays a role in the phagocytosis by monocytes/macrophages. Proteases released from granulocytes in the clot break down activated FXIII. Clinical studies on FXIII New methods on the measurement of FXIII activity, and on the detection of FXIII-A Val34Leu polymorphism. Method on the detection of intracellular FXIII-A and its application to the diagnosis of acute myeloid leukemias. Bone marrow ablation results in the significant decrease of plasma FXIII level; in myeloproliferative diseases with high platelet count plasma FXIII is elevated. In women elevated FXIII level increases the risk for myocardial infarction by more than two-folds. In chronic bronchoalveolar inflammation the amount of FXIII in the lavage fluid is significantly increased. Description of four new mutations in FXIII deficient patients, and protein structural analysis of their consequences. It was demonstrated on FXIII deficient transgene mice that FXIII is required for normal wound healing
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