Fixed-dose pyronaridine-artesunate combination for treatment of uncomplicated falciparum malaria in pediatric patients in Gabon

BACKGROUND: The development of novel artemisinin-combination therapies suitable for the treatment of pediatric patients suffering from malaria is a research priority. The aim of this study was to investigate a novel fixed-dose pyronaridine-artesunate combination for the treatment of uncomplicated falciparum malaria in Gabonese patients 2-14 years old. METHODS: The study was designed as an open-label dose-escalation study recruiting 60 pediatric patients sequentially in 4 treatment cohorts: study drugs were administered once daily for 3 days, as tablet coformulations (pyronaridine:artesunate ratios of 6:2, 9:3, and 12:4 mg/kg) and as a granule coformulation (pyronaridine:artesunate ratio of 9:3 mg/kg). The primary end points were tolerability, safety, and pharmacokinetics of pyronaridine-artesunate treatment. Efficacy was treated as a secondary outcome measure. RESULTS: The drugs had a good tolerability and safety profile, at all dose levels. Pharmacokinetic analysis revealed a dose-dependent increase in the maximum plasma/blood concentration and the area under the curve, as well as comparable relative bioavailability for the granule coformulation. Polymerase chain reaction-corrected cure rates at day 28 were 100% in per-protocol analysis, at all dose levels. CONCLUSIONS: Pyronaridine-artesunate is a promising novel artemisinin-combination therapy for pediatric patients with uncomplicated Plasmodium falciparum malaria, and the development of both the tablet and the granule coformulations is warranted.     

Conformation of peptides bound to the transporter associated with antigen processing (TAP)

The ATP-binding cassette transporter associated with antigen processing (TAP) plays a key role in the adaptive immune defense against infected or malignantly transformed cells by translocating proteasomal degradation products into the lumen of the endoplasmic reticulum for loading onto MHC class I molecules. The broad substrate spectrum of TAP, rendering peptides from 8 to 40 residues, including even branched or modified molecules, suggests an unforeseen structural flexibility of the substrate-binding pocket. Here we used EPR spectroscopy to reveal conformational details of the bound peptides. Side-chain dynamics and environmental polarity were derived from covalently attached 2,2,5,5-tetramethylpyrrolidine-1-oxyl spin probes, whereas 2,2,6,6-tetramethylpiperidine-1-oxyl-4-amino-4-carboxylic acid spin-labeled peptides were used to detect backbone properties. Dependent on the spin probe's position, striking differences in affinity, dynamics, and polarity were found. The side-chains' mobility was strongly restricted at the ends of the peptide, whereas the central region was flexible, suggesting a central peptide bulge. In the end, double electron electron resonance allowed the determination of intrapeptide distances in doubly labeled peptides bound to TAP. Simulations based on a rotamer library led to the conclusion that peptides bind to TAP in an extended kinked structure, analogous to those bound to MHC class I proteins.     

Anticoagulants affect matrix metalloproteinase 9 levels in blood samples of stroke patients and healthy controls

ObjectivesMatrix metalloproteinase-9 (MMP-9) represents a promising marker for acute stroke management. In clinical studies MMP-9 has been quantified by ELISA using differing protocols. We aimed to establish a valid protocol by evaluation of preanalytics.Design and methodsBlood from stroke patients (n = 28) and healthy controls (n = 28) was drawn into tubes containing different anticoagulants (EDTA, citrate, lithium-heparin (heparin) and heparin with proteinase inhibitors) and processed after 0, 60 and 240 min. MMP-9 plasma protein and mRNA from mononuclear leukocytes were determined.ResultsIn regard to anticoagulants used, samples showed different MMP-9 protein baseline values and kinetics. Stable MMP-9 protein concentrations were only measured from EDTA samples. Particularly in samples with proteinase inhibitors protein and mRNA concentrations increased over time. Kinetics did not differ between patients and controls.ConclusionsPreanalytics plays a key role for determination of MMP-9. EDTA seems to be a valid anticoagulant for MMP-9 protein measurement.     

Acidified seawater impacts sea urchin larvae pH regulatory systems relevant for calcification

Calcifying echinoid larvae respond to changes in seawater carbonate chemistry with reduced growth and developmental delay. To date, no information exists on how ocean acidification acts on pH homeostasis in echinoderm larvae. Understanding acid–base regulatory capacities is important because intracellular formation and maintenance of the calcium carbonate skeleton is dependent on pH homeostasis. Using H⁺-selective microelectrodes and the pH-sensitive fluorescent dye BCECF, we conducted in vivo measurements of extracellular and intracellular pH (pH_e and pH_i) in echinoderm larvae. We exposed pluteus larvae to a range of seawater CO₂ conditions and demonstrated that the extracellular compartment surrounding the calcifying primary mesenchyme cells (PMCs) conforms to the surrounding seawater with respect to pH during exposure to elevated seawater pCO₂. Using FITC dextran conjugates, we demonstrate that sea urchin larvae have a leaky integument. PMCs and spicules are therefore directly exposed to strong changes in pH_e whenever seawater pH changes. However, measurements of pH_i demonstrated that PMCs are able to fully compensate an induced intracellular acidosis. This was highly dependent on Na⁺ and HCO₃⁻, suggesting a bicarbonate buffer mechanism involving secondary active Na⁺-dependent membrane transport proteins. We suggest that, under ocean acidification, maintained pH_i enables calcification to proceed despite decreased pH_e. However, this probably causes enhanced costs. Increased costs for calcification or cellular homeostasis can be one of the main factors leading to modifications in energy partitioning, which then impacts growth and, ultimately, results in increased mortality of echinoid larvae during the pelagic life stage.     

Reactivations of Latent Viral Infections Are Associated with an Increased Thr389 p70S6k Phosphorylation in Peripheral Lymphocytes of Renal Transplant Recipients

Reactivations of BK polyoma virus (BKPyV) and human cytomegalovirus (HCMV) frequently cause life- and graft-threatening complications after renal transplantation. Both viruses are dependent on the mTOR pathway for replication. In this study we investigated the association of viral replication with mTOR activity in peripheral lymphocytes of renal transplant recipients. A flow-cytometry based assay for the measurement of Thr389 p70S6k phosphorylation, a surrogate marker of the mTOR pathway was established. Forty-eight adult renal transplant recipients were recruited to measure p70S6k activity in their peripheral blood mononuclear cells. This data set in conjunction with information concerning previous replication of BKPyV and HCMV was examined for correlations. Episodes of BKPyV replication were significantly associated with increased p70S6k phosphorylation in CD4⁺ T lymphocytes (p = 0.0002) and CD19⁺ B lymphocytes (p = 0.0073). HCMV infection of patients with a high-risk HCMV constellation of donor and recipient (D+/R−) was associated with increased p70S6k phosphorylation in CD19⁺ B lymphocytes (p = 0.0325). These associations were found to be independent of the trough levels of the immunosuppressive drugs. Conclusion: P70S6k phosphorylation in peripheral lymphocytes is associated with BKPyV reactivations and to a lesser extent with HCMV infections in renal transplant recipients.     

Expressive Suppression of Emotions and Overeating in Individuals with Overweight and Obesity

Emotions have a considerable impact on eating behaviour; however, research addressing emotion regulation in obesity is rare. The present study is the first to investigate the association between emotional suppression and overeating in individuals with overweight. In total, 314 participants including 190 individuals with obesity filled in a cross‐sectional online survey, which assessed emotional suppression, eating behaviour and psychopathology. A hierarchical linear regression analysis was conducted to identify factors associated with overeating. Individuals with obesity reported more frequent overeating compared with individuals without obesity. The habitual use of emotional suppression was associated with more overeating; however, this link was moderated by increased body mass index (BMI). The results suggest that suppression of emotional expression contributes to overeating and is maladaptive especially in individuals with obesity. Further research should longitudinally investigate the predictive value of emotional suppression on overweight, as the training of emotion regulation could contribute to treating obesity. Copyright © 2016 John Wiley & Sons, Ltd and Eating Disorders Association.     

Targeting the Complement Serine Protease MASP-2 as a Therapeutic Strategy for Coronavirus Infections

MASP-2, mannose-binding protein-associated serine protease 2, is a key enzyme in the lectin pathway of complement activation. Hyperactivation of this protein by human coronaviruses SARS-CoV, MERS-CoV and SARS-CoV-2 has been found to contribute to aberrant complement activation in patients, leading to aggravated lung injury with potentially fatal consequences. This hyperactivation is triggered in the lungs through a conserved, direct interaction between MASP-2 and coronavirus nucleocapsid (N) proteins. Blocking this interaction with monoclonal antibodies and interfering directly with the catalytic activity of MASP-2, have been found to alleviate coronavirus-induced lung injury both in vitro and in vivo. In this study, a virtual library of 8736 licensed drugs and clinical agents has been screened in silico according to two parallel strategies. The first strategy aims at identifying direct inhibitors of MASP-2 catalytic activity, while the second strategy focusses on finding protein-protein interaction inhibitors (PPIs) of MASP-2 and coronaviral N proteins. Such agents could represent promising support treatment options to prevent lung injury and reduce mortality rates of infections caused by both present and future-emerging coronaviruses. Forty-six drug repurposing candidates were purchased and, for the ones selected as potential direct inhibitors of MASP-2, a preliminary in vitro assay was conducted to assess their interference with the lectin pathway of complement activation. Some of the tested agents displayed a dose-response inhibitory activity of the lectin pathway, potentially providing the basis for a viable support strategy to prevent the severe complications of coronavirus infections.     

Hepatocellular carcinoma in Gaucher disease: an international case series

Gaucher disease (GD) is associated with an increased risk for malignancies. Next to hematological malignancies, the development of solid tumors in several organs has been described. The liver is one of the major storage sites involved in GD pathogenesis, and is also affected by liver-specific complications. In this case series, we describe 16 GD type 1 (GD1) patients from eight different referral centers around the world who developed hepatocellular carcinoma (HCC). Potential factors contributing to the increased HCC risk in GD patients are studied. Eleven patients had undergone a splenectomy in the past. Liver cirrhosis, one of the main risk factors for the development of HCC, was present in nine out of 14 patients for whom data was available. Three out of seven examined patients showed a transferrin saturation?>?45%. In these three patients the presence of iron overload after histopathological examination of the liver was shown. Chronic hepatitis C infection was present in three of 14 examined cases. We summarized all findings and made a comparison to the literature. We recommend that GD patients, especially those with prior splenectomy or iron overload, be evaluated for signs of liver fibrosis and if found to be monitored for HCC development.     

Allogeneic haematopoietic stem cell transplantation in relapsed or refractory anaplastic large cell lymphoma of children and adolescents--a Berlin-Frankfurt-Münster group report

Patients with refractory or early relapsed anaplastic large cell lymphoma (ALCL) have a poor chance of survival. We report 20 children and adolescents with high-risk relapsed or refractory ALCL who underwent allogeneic haematopoietic stem cell transplantation (HSCT). We retrospectively analysed 20 patients who relapsed between December 1991 and April 2003 during (six patients) or soon after first-line Berlin-Frankfurt-Münster-type chemotherapy (14 patients) and underwent allogeneic HSCT. Nine patients received allogeneic HSCT after the first relapse and 11 after multiple relapses. Eight patients received their transplants from matched sibling donors, eight from unrelated donors and four from haploidentical family donors. The conditioning regimen was based on total body irradiation in 15 patients. Two patients relapsed after allogeneic HSCT and died. Three patients died of transplant-related toxicity. Event-free survival at 3 years after allogeneic transplant was 75 +/- 10%. There was no influence of donor type or conditioning regimen on outcome. Two of six patients with progressive disease during frontline therapy survived compared with 13/14 patients with a first relapse after frontline therapy. Two of three patients who were transplanted with active lymphoma and all five patients who received allogeneic HSCT for relapse following autologous HSCT survived disease-free. Allogeneic HSCT is effective and has acceptable toxicity as rescue therapy for high-risk ALCL relapse. It even offers cure for patients refractory to chemotherapy, suggesting a graft-versus-ALCL effect.     

Generation of activation-specific human anti-alphaMbeta2 single-chain antibodies as potential diagnostic tools and therapeutic agents

The leukocyte integrin Mac-1 (alpha(M)beta(2)) plays a pivotal role in inflammation and host defense. Upon leukocyte activation, Mac-1 undergoes a conformational change exposing interaction sites for multiple ligands. We aimed to generate single-chain antibodies (scFv's) directed against activation-specific Mac-1 ligand-binding sites. Using human scFv phage libraries, we developed subtractive strategies with depletion of phages binding to nonactivated Mac-1 and selection of phages binding to activated Mac-1, using monocytes as well as CHO cells transfected with native or mutated, activated Mac-1. Three scFv clones demonstrated exclusive binding to activated Mac-1. Mac-1 binding of the ligands fibrinogen, heparin, and ICAM-1, but not C3bi, was inhibited. Using alanine substitutions, the paratope was identified within the heavy chain HCDR3s of the scFv's. The epitope was localized to Lys(245)-Arg(261) of the alpha(M) I-domain. In a pilot study with septicemic patients, we provide initial support for the use of these scFv's as markers of monocyte activation and as potential diagnostic tools. Potential therapeutic use was tested in adhesion assays under static and flow conditions demonstrating the selective blockade of activated monocytes only. Furthermore, scFv HCDR3-derived peptides retain selectivity for the activated integrin, providing a unique template for the potential development of inhibitors that are specific for the activated Mac-1.