Oxygen in Red Blood Cell Concentrates: Influence of Donors' Characteristics and Blood Processing.

Unexpectedly wide distribution (<10 to >90%) of hemoglobin oxygen saturation (sO) within red cell concentrates (RCCs) has recently been observed. Causes of such variability are not yet completely explained whereas the roles of oxygen and oxidative lesions during the storage of RCCs are known. The objectives of the present study are to characterize sO distribution in RCCs produced in a Swiss blood center and to investigate the influence of processing and donors' characteristics.

Sulfenylome analysis of pathogen-inactivated platelets reveals the presence of cysteine oxidation in integrin signaling pathway and cytoskeleton regulation.

Essentials Cysteine oxidation to sulfenic acid plays a key role in redox regulation and signal transduction. Platelet sulfenylome was studied by quantitative proteomics in pathogen inactivated platelets. One hundred and seventy-four sulfenylated proteins were identified in resting platelets.

Hypoxia and hypocapnia storage of γ-irradiated red cell concentrates.

Background: γ-irradiation is used to treat red blood cell (RBC) concentrates (RCCs) transfused to immunosuppressed patients. This treatment damages RBCs and increases storage lesions. Several studies have shown the beneficial effect of reducing O content during RBC storage.

Antioxidant power measurement in platelet concentrates treated by two pathogen inactivation systems in different blood centres.

Background And Objectives: The antioxidant power measurement can be useful to validate the execution of the pathogen inactivation treatment of platelet concentrates. The aim of this study is to evaluate the technology on different blood preparations including INTERCEPT and Mirasol treatments that are in routine use in Belgium and Luxemburg.

Materials And Methods: The antioxidant power measurement was tested on 78 apheresis platelet concentrates and 54 pools of buffy-coats-derived platelet concentrates before and after INTERCEPT treatment.

Transfusion-transmitted cytomegalovirus: behaviour of cell-free virus during blood component processing. A study on the safety of labile blood components in Switzerland.

Background: Nowadays, most blood products are leukocyte-reduced. After this procedure, the residual risk for transfusion transmitted cytomegalovirus (TT-CMV) is mostly attributed to cell-free viruses in the plasma of blood donors following primary infection or viral reactivation. Here, objectives are: 1) to study the behaviour of cell-free CMV through the blood component processing; 2) to determine the anti-CMV seroprevalence, the level of viremia, the window-period in blood donor population; and 3) to identify cases of TT-CMV in bone marrow transplant (BMT) recipients.

General overview of blood products in vitro quality: Processing and storage lesions.

Blood products are issued from blood collection. Collected blood is immediately mixed with anticoagulant solutions that immediately induce chemical and/or biochemical modifications. Collected blood is then transformed into different blood products according to various steps of fabrication.

Redox Proteomics and Platelet Activation: Understanding the Redox Proteome to Improve Platelet Quality for Transfusion.

Blood banks use pathogen inactivation (PI) technologies to increase the safety of platelet concentrates (PCs). The characteristics of PI-treated PCs slightly differ from those of untreated PCs, but the underlying reasons are not well understood. One possible cause is the generation of oxidative stress during the PI process.

Antioxidant power as a quality control marker for completeness of amotosalen and ultraviolet A photochemical treatments in platelet concentrates and plasma units.

Background: Pathogen inactivation treatments such as INTERCEPT aim to make sure blood and blood-derived products are free of pathogens before using them for transfusion purposes. At present, there is no established quality control assay that assesses the completeness of the treatment. As INTERCEPT is a photochemical treatment known to generate reactive oxygen species we sought to use the antioxidant power (AOP) of the blood product as a marker of treatment execution.

Small-Scale Perfusion Bioreactor of Red Blood Cells for Dynamic Studies of Cellular Pathways: Proof-of-Concept.

To date, the development of bioreactors for the study of red blood cells (RBCs, daily transfused in the case of disease or hemorrhage) has focused on hematopoietic stem cells. Despite the fact that mature RBCs are enucleated and do not expand, they possess complex cellular and metabolic pathways, as well as post-translation modification signaling and gas-exchange regulation. In order to dynamically study the behavior of RBCs and their signaling pathways under various conditions, a small-scale perfusion bioreactor has been developed.

In vitro study of platelet function confirms the contribution of the ultraviolet B (UVB) radiation in the lesions observed in riboflavin/UVB-treated platelet concentrates.

Background: Platelet inactivation technologies (PITs) have been shown to increase platelet storage lesions (PSLs). This study investigates amotosalen/ultraviolet (UV)A- and riboflavin/UVB-induced platelet (PLT) lesions in vitro. Particular attention is given to the effect of UVB alone on PLTs.

In vitro evaluation of pathogen-inactivated buffy coat-derived platelet concentrates during storage: psoralen-based photochemical treatment step-by-step.

Background: The Intercept Blood SystemTM (Cerus) is used to inactivate pathogens in platelet concentrates (PC). The aim of this study was to elucidate the extent to which the Intercept treatment modifies the functional properties of platelets.

Material And Methods: A two-arm study was conducted initially to compare buffy coat-derived pathogen-inactivated PC to untreated PC (n=5) throughout storage.

The clinical and biological impact of new pathogen inactivation technologies on platelet concentrates.

Since 1990, several techniques have been developed to photochemically inactivate pathogens in platelet concentrates, potentially leading to safer transfusion therapy. The three most common methods are amotosalen/UVA (INTERCEPT Blood System), riboflavin/UVA-UVB (MIRASOL PRT), and UVC (Theraflex-UV). We review the biology of pathogen inactivation methods, present their efficacy in reducing pathogens, discuss their impact on the functional aspects of treated platelets, and review clinical studies showing the clinical efficiency of the pathogen inactivation methods and their possible toxicity.

LC-MS/MS analysis and comparison of oxidative damages on peptides induced by pathogen reduction technologies for platelets.

Pathogen reduction technologies (PRT) are photochemical processes that use a combination of photosensitizers and UV-light to inactivate pathogens in platelet concentrates (PCs), a blood-derived product used to prevent hemorrhage. However, different studies have questioned the impact of PRT on platelet function and transfusion efficacy, and several proteomic analyses revealed possible oxidative damages to proteins. The present work focused on the oxidative damages produced by the two main PRT on peptides.

Gene network and proteomic analyses of cardiac responses to pathological and physiological stress.

Background: The molecular mechanisms underlying similarities and differences between physiological and pathological left ventricular hypertrophy (LVH) are of intense interest. Most previous work involved targeted analysis of individual signaling pathways or screening of transcriptomic profiles. We developed a network biology approach using genomic and proteomic data to study the molecular patterns that distinguish pathological and physiological LVH.

Lysis-on-chip of single target cells following forced interaction with CTLs or NK cells on a dielectrophoresis-based array.

Guiding the interaction of single cells acting as partners in heterotypic interactions (e.g., effectors and targets of immune lysis) and monitoring the outcome of these interactions are regarded as crucial biomedical achievements.

Extracellular matrix secretion by cardiac fibroblasts: role of microRNA-29b and microRNA-30c.

Rationale: MicroRNAs (miRNAs), in particular miR-29b and miR-30c, have been implicated as important regulators of cardiac fibrosis.

Objective: To perform a proteomics comparison of miRNA effects on extracellular matrix secretion by cardiac fibroblasts.

Methods And Results: Mouse cardiac fibroblasts were transfected with pre-/anti-miR of miR-29b and miR-30c, and their conditioned medium was analyzed by mass spectrometry.

Highlights from the 2010 BAS/BSCR spring meeting: New Frontiers in Cardiovascular Research.

The British Atherosclerosis Society (BAS)/British Society for Cardiovascular Research (BSCR) spring meeting was held in Manchester, UK, on 7-8 June 2010. Experts in the field of systems biology, proteomics, metabolomics and miRNAs presented how these techniques can be used to discover 'New Frontiers in Cardiovascular Research'. The conference was attended by over 150 participants, mainly from the UK.

Electrochemical aspects of electrospray and laser desorption/ionization for mass spectrometry.

Soft-ionization methods, namely electrospray ionization and laser desorption/ionization, are widely used to transfer large molecules as intact gas-phase ions either from a solution or from a solid substrate. During both processes, in-source electrochemical and photoelectrochemical reactions occur. These electrode reactions, which take place at interfaces, play important roles in influencing the ionization products, but they have received little attention.

Electrochemical reactions and ionization processes.

Electrochemical or photo-electrochemical reactions in both electrospray ionization and laser desorption ionization are discussed stressing the role of the electrode reaction in influencing the ionization process. In particular, upon application of a high voltage during electrospray ionization, the emitter includes a working electrode, where redox reactions are observed, such as electro-generation of benzoquinone and metal ions. In contrast, the target plate in laser-induced desorption ionization also acts as a photo-electrode, especially when modified with a mesoporous semiconductor.

Magnetic track array for efficient bead capture in microchannels.

Magnetism-based microsystems, as those dedicated to immunoaffinity separations or (bio)chemical reactions, take benefit of the large surface area-to-volume ratio provided by the immobilized magnetic beads, thus increasing the sensitivity of the analysis. As the sensitivity is directly linked to the efficiency of the magnetic bead capture, this paper presents a simple method to enhance the capture in a microchannel. Considering a microchannel surrounded by two rectangular permanent magnets of different length (L (m) = 2, 5, 10 mm) placed in attraction, it is shown that the amount of trapped beads is limited by the magnetic forces mainly located at the magnet edges.

Magnetic forces produced by rectangular permanent magnets in static microsystems.

Finite element numerical simulations were carried out in 2D geometries to map the magnetic field and force distribution produced by rectangular permanent magnets as a function of their size and position with respect to a microchannel. A single magnet, two magnets placed in attraction and in repulsion have been considered. The goal of this work is to show where magnetic beads are preferentially captured in a microchannel.

Sandwich mixer-reactor: influence of the diffusion coefficient and flow rate ratios.

A sandwich mixer consists of mixing two solutions in a channel, one central laminar flow being sandwiched between two outer flow solutions. The present numerical study considers the convection-diffusion of two reacting species A and B, provided respectively by the two incoming solutions. The simulations show how the diffusion coefficient, flow rate and species concentration ratios influence, via the transversal diffusion length and reaction kinetics, the reaction extent at the end of the sandwich mixer.

Electrospray micromixer chip for on-line derivatization and kinetic studies.

An electrospray microchip for mass spectrometry comprising an integrated passive mixer to carry out on-chip chemical derivatizations is described. The microchip fabricated using UV-photoablation is composed of two microchannels linked together by a liquid junction. Downstream of this liquid junction, a mixing unit made of parallel oblique grooves is integrated to the microchannel in order to create flow perturbations.