International normalized ratio measurement during perioperative anticoagulation bridging with low-molecular-weight heparin in patients undergoing heart valve replacement surgery.

Background: Surgical procedures in anticoagulated patients require specific attention due to increased bleeding risk. Preoperative anticoagulation interruption in high-risk patients is often necessary. Bridging anticoagulation with low-molecular-weight heparin (LMWH) minimizes thromboembolic risk, but its effect on international normalized ratio (INR) measurement is not well established, necessitating careful monitoring and individual assessment.

Enhanced thrombin and plasmin generation profiles in alpha-2-antiplasmin-deficient patients: Data from the Rare Bleeding disorders in the Netherlands study.

Background: α2-Antiplasmin (A2AP) deficiency is a rare and often unidentified disorder characterized by increased fibrinolysis and subsequent bleeding. Global hemostasis assays may increase insight into the altered coagulation and fibrinolysis in these patients.

Objectives: To explore thrombin and plasmin generation profiles in A2AP-deficient patients, corresponding A2AP activity levels and associated bleeding phenotypes.

Gastrointestinal Angiodysplasia Resolution After Transcatheter Aortic Valve Implantation.

Importance: Heyde syndrome is the cooccurrence of aortic stenosis and gastrointestinal bleeding secondary to vascular lesions, including angiodysplasias. Several studies have demonstrated cessation of gastrointestinal bleeding after transcatheter aortic valve implantation (TAVI), but the etiology and effects on vascular lesions are largely unknown.

Objective: To examine the associations of TAVI with gastrointestinal vascular lesions and identify factors associated with recovery among patients with iron deficiency anemia and severe aortic stenosis.

Targeted exome analysis in patients with rare bleeding disorders: data from the Rare Bleeding Disorders in the Netherlands study.

Background: Rare coagulation factor deficiencies and disorders of fibrinolysis (defined as rare bleeding disorders [RBDs]) present with a heterogeneous bleeding phenotype, and bleeding severity is difficult to predict.

Objectives: Describe underlying rare genetic variants in the Dutch RBD population and investigate the relationship between genotype, laboratory phenotype, and clinical phenotype.

Methods: The Rare Bleeding Disorders in the Netherlands is a cross-sectional, nationwide study conducted between October 1, 2017, and November 30, 2019.

Comparative analysis of thrombin generation platforms for patients with coagulation factor deficiencies: A comprehensive assessment.

Introduction: Thrombin generation assays (TGAs) assess the overall functionality of the hemostatic system and thereby provide a reflection of the hemostatic capacity of patients with disorders in this system. Currently, four (semi-)automated TGA platforms are available: the Calibrated Automated Thrombogram, Nijmegen Hemostasis Assay, ST Genesia and Ceveron s100. In this study, we compared their performance for detecting patients with congenital single coagulation factor deficiencies.

The spectrum of neutralizing and non-neutralizing anti-FVIII antibodies in a nationwide cohort of 788 persons with hemophilia A.

Objectives: Anti-factor VIII (FVIII) antibodies have been reported to exhibit both neutralizing and non-neutralizing characteristics. This is the first study investigating the full spectrum of FVIII-specific antibodies, including non-neutralizing antibodies, very-low titer inhibitors, and inhibitors, in a large nationwide population of persons with hemophilia A of all severities.

Methods: All persons with hemophilia A (mild (FVIII > 5-40 IU/dL)/moderate [FVIII 1-5 IU/dL)/severe (FVIII < 1 IU/dL)] with an available plasma sample who participated in the study between 2018 and 2019 were included.

The Nijmegen ultra-sensitive Bethesda Assay detects very low-titer factor VIII inhibitors in patients with congenital and acquired hemophilia A.

Background: An inhibitor can develop in congenital hemophilia A (HA) patients against exogenous infused factor (F)VIII, whereas in acquired HA (AHA) inhibitors initially develop against endogenous FVIII. Inhibitors can be detected with the Nijmegen Bethesda Assay (NBA), which has an international cut-off level of 0.60 Nijmegen Bethesda Units/mL (NBU/mL).

Patients with moderate hemophilia A and B with a severe bleeding phenotype have an increased burden of disease.

Background: Patients with moderate hemophilia express varying bleeding phenotypes.

Objectives: To assess the burden of disease in patients with moderate hemophilia and a mild or severe phenotype incorporating the thrombin generation profile.

Methods: This sub-study of the 6th Hemophilia in the Netherlands study, analyzed data of adults with moderate hemophilia A or B.

Thrombin generation assays to personalize treatment in bleeding and thrombotic diseases.

Treatment of bleeding and thrombotic disorders is highly standardized and based on evidence-based medicine guidelines. These evidence-based treatment schemes are well accepted but may lead to either insufficient treatment or over-dosing, because the individuals' hemostatic properties are not taken into account. This can potentially introduce bleeding or thrombotic complications in individual patients.

Ex Vivo Machine Thrombolysis Reduces Rethrombosis Rates in Salvaged Thrombosed Myocutaneous Flaps in Swine.

Background: There is a risk for thrombotic complications (2 to 5 percent) associated with microsurgical reconstruction. Current thrombolytic therapy has a salvage rate between 60 and 70 percent, but it is afflicted by bleeding complications (2 to 6 percent). The use of machine perfusion for delivering thrombolytic agents is a new method that could potentially reduce these complications.

Naturally acquired immunity against immature gametocytes.

The recent decline in global malaria burden has stimulated efforts toward elimination. Understanding the biology of malaria transmission stages may provide opportunities to reduce or prevent onward transmission to mosquitoes. Immature transmission stages, termed stages I to IV gametocytes, sequester in human bone marrow before release into the circulation as mature stage V gametocytes.

The bias between different albumin assays may affect clinical decision-making.

Differences between laboratory assays can have important clinical implications. For creatinine assays this became apparent soon after the introduction of the Modification of Diet in Renal Disease formula and resulted in international efforts towards standardization. Albumin in blood is measured by different assays, either chromogenic using Bromocresol green (BCG) or Bromocresol purple (BCP), or by an immunoassay.

Proguanil and cycloguanil are organic cation transporter and multidrug and toxin extrusion substrates.

Background: Malaria, HIV/AIDS, and tuberculosis endemic areas show considerable geographical overlap, leading to incidence of co-infections. This requires treatment with multiple drugs, potentially causing adverse drug-drug interactions (DDIs). As anti-malarials are generally positively charged at physiological pH, they are likely to interact with human organic cation transporters 1 and 2 (OCT1 and OCT2).

Comparative assessment of An. gambiae and An. stephensi mosquitoes to determine transmission-reducing activity of antibodies against P. falciparum sexual stage antigens.

Background: With the increasing interest in vaccines to interrupt malaria transmission, there is a demand for harmonization of current methods to assess Plasmodium transmission in laboratory settings. Potential vaccine candidates are currently tested in the standard membrane feeding assay (SMFA) that commonly relies on Anopheles stephensi mosquitoes. Other mosquito species including Anopheles gambiae are the dominant malaria vectors for Plasmodium falciparum in sub-Saharan Africa.

A Molecular Assay to Quantify Male and Female Plasmodium falciparum Gametocytes: Results From 2 Randomized Controlled Trials Using Primaquine for Gametocyte Clearance.

Background: Single low-dose primaquine (PQ) reduces Plasmodium falciparum infectivity before it impacts gametocyte density. Here, we examined the effect of PQ on gametocyte sex ratio as a possible explanation for this early sterilizing effect.

Methods: Quantitative reverse-transcription polymerase chain reaction assays were developed to quantify female gametocytes (targeting Pfs25 messenger RNA [mRNA]) and male gametocytes (targeting Pf3D7_1469900 mRNA) in 2 randomized trials in Kenya and Mali, comparing dihydroartemisinin-piperaquine (DP) alone to DP with PQ.

A Direct from Blood Reverse Transcriptase Polymerase Chain Reaction Assay for Monitoring Falciparum Malaria Parasite Transmission in Elimination Settings.

We describe a novel one-step reverse transcriptase real-time PCR (direct RT-PCR) for malaria parasites that amplifies RNA targets directly from blood. We developed the assay to identify gametocyte-specific transcripts in parasites from patient blood samples, as a means of monitoring malaria parasite transmission in field settings. To perform the test, blood is added directly to a master mix in PCR tubes and analyzed by real-time PCR.

Molecular Markers for Sensitive Detection of Asexual Stage Parasites and their Application in a Malaria Clinical Trial.

parasite life stages respond differently to antimalarial drugs. Sensitive stage-specific molecular assays may help to examine parasite dynamics at microscopically detectable and submicroscopic parasite densities in epidemiological and clinical studies. In this study, we compared the performance of skeleton-binding protein 1 (SBP1), ring-infected erythrocyte surface antigen, Hyp8, ring-exported protein 1 (REX1), and PHISTb mRNA for detecting ring-stage trophozoite-specific transcripts using quantitative reverse transcriptase polymerase chain reaction.

Integrated transcriptomic and proteomic analyses of P. falciparum gametocytes: molecular insight into sex-specific processes and translational repression.

Sexual differentiation of malaria parasites into gametocytes in the vertebrate host and subsequent gamete fertilization in mosquitoes is essential for the spreading of the disease. The molecular processes orchestrating these transitions are far from fully understood. Here, we report the first transcriptome analysis of male and female Plasmodium falciparum gametocytes coupled with a comprehensive proteome analysis.

Protective Efficacy Induced by Genetically Attenuated Mid-to-Late Liver-Stage Arresting Plasmodium berghei Δmrp2 Parasites.

Whole parasite immunization strategies employing genetically attenuated parasites (GAP), which arrest during liver-stage development, have been applied successfully for induction of sterile malaria protection in rodents. Recently, we generated a Plasmodium berghei GAP-lacking expression of multidrug resistance-associated protein (MRP2) (PbΔmrp2) that was capable of partial schizogony in hepatocytes but showed complete growth arrest. Here, we investigated the protective efficacy after intravenous (IV) immunization of BALB/c and C57BL/6J mice with PbΔmrp2 sporozoites.

Vital and dispensable roles of Plasmodium multidrug resistance transporters during blood- and mosquito-stage development.

Multidrug resistance (MDR) proteins belong to the B subfamily of the ATP Binding Cassette (ABC) transporters, which export a wide range of compounds including pharmaceuticals. In this study, we used reverse genetics to study the role of all seven Plasmodium MDR proteins during the life cycle of malaria parasites. Four P.

MRP1 mediates folate transport and antifolate sensitivity in Plasmodium falciparum.

Multidrug resistance-associated proteins (MRP) of Plasmodium falciparum have been associated with altered drug sensitivity. Knowledge on MRP substrate specificity is indispensible for the characterization of resistance mechanisms and identifying its physiological roles. An untargeted metabolomics approach detected decreased folate concentrations in red blood cells infected with schizont stage parasites lacking expression of MRP1.

Naturally acquired immunity to sexual stage P. falciparum parasites.

Gametocytes are the specialized form of Plasmodium parasites that are responsible for human-to-mosquito transmission of malaria. Transmission of gametocytes is highly effective, but represents a biomass bottleneck for the parasite that has stimulated interest in strategies targeting the transmission stages separately from those responsible for clinical disease. Studying targets of naturally acquired immunity against transmission-stage parasites may reveal opportunities for novel transmission reducing interventions, particularly the development of a transmission blocking vaccine (TBV).

Multidrug ATP-binding cassette transporters are essential for hepatic development of Plasmodium sporozoites.

Multidrug resistance-associated proteins (MRPs) belong to the C-family of ATP-binding cassette (ABC) transport proteins and are known to transport a variety of physiologically important compounds and to be involved in the extrusion of pharmaceuticals. Rodent malaria parasites encode a single ABC transporter subfamily C protein, whereas human parasites encode two: MRP1 and MRP2. Although associated with drug resistance, their biological function and substrates remain unknown.

PfMDR2 and PfMDR5 are dispensable for Plasmodium falciparum asexual parasite multiplication but change in vitro susceptibility to anti-malarial drugs.

Background: Membrane-associated ATP binding cassette (ABC) transport proteins hydrolyze ATP in order to translocate a broad spectrum of substrates, from single ions to macromolecules across membranes. In humans, members from this transport family have been linked to drug resistance phenotypes, e.g.