Irreversible oxidations of platelet proteins after riboflavin-UVB pathogen inactivation.

Pathogen inactivation technologies are known to alter in vitro phenotype and functional properties of platelets. Because pathogen inactivation generates reactive oxygen species, oxidative stress is considered as one of the plausible cause at the origin of the platelet storage lesion acceleration after treatment. To date proteomics has been used to document the protein variations to picture out the impact. Here, platelet concentrates were prepared from buffy-coats in Intersol additive solution, leukoreduced and pathogen inactivated using a riboflavin/UVB treatment. At day 2 of storage the platelet proteomes of control (untreated) and treated platelet concentrates were investigated against the site specific oxidation by liquid chromatography coupled to tandem mass spectrometry in a shotgun experiment. The shotgun approach detected 9350 peptides (and 2534 proteins) of which 1714 were oxidized. Eighteen peptides were found exclusively oxidized in treated platelets whereas 3 peptides were only found oxidized in control. The present data evidenced an interference with several proteins involved in platelet aggregation and platelet shape change (such as talin and vinculin).

The antioxidant capacity of erythrocyte concentrates is increased during the first week of storage and correlated with the uric acid level.

BACKGROUND AND OBJECTIVES: Red blood cells (RBCs) suffer from lesions during cold storage, depending in part on their ability to counterbalance oxidative stress by activating their antioxidant defence. The aim of this study was to monitor the antioxidant power (AOP) in erythrocyte concentrates (ECs) during cold storage. MATERIALS AND METHODS: Six ECs were prepared in saline-adenine-glucose-mannitol (SAGM) additive solution and followed during 43 days. The AOP was quantified electrochemically using disposable electrode strips and compared with results obtained from a colorimetric assay. Haematological data, data on haemolysis and the extracellular concentration of uric acid were also recorded. Additionally, a kinetic model was developed to extract quantitative kinetic data on the AOP behaviour. RESULTS: The AOP of total ECs and their extracellular samples attained a maximum after 1 week of storage prior to decaying and reaching a plateau, as shown by the electrochemical measurements. The observed trend was confirmed with a colorimetric assay. Uric acid had a major contribution to the extracellular AOP. Interestingly, the AOP and uric acid levels were linked to the sex of the donors. CONCLUSION: The marked increase in AOP during the first week of storage suggests that RBCs are impacted early by the modification of their environment. The AOP behaviour reflects the changes in metabolism activity following the adjustment of the extracellular uric acid level. Knowing the origin, interdonor variability and the effects of the AOP on the RBCs could be beneficial for the storage quality, which will have to be further studied.

Automatic washing of thawed haematopoietic progenitor cell grafts: a preclinical evaluation.

BACKGROUND AND OBJECTIVES: Autologous haematopoietic progenitor cell (HPC) is a prerequisite for high-dose chemotherapy in treatment of several haematologic and non-haematologic malignancies. HPCs are collected by apheresis and cryopreserved until infusion. Postinfusion adverse events have been in part related to the dimethyl sulphoxide (DMSO) used as cryoprotectant. The aim was to evaluate (i) an automated sequential washing procedure for DMSO removal in thawed HPC grafts and (ii) washing solutions in replacement of hydroxyethyl starch (HES)-based solutions. MATERIALS AND METHODS: A total of 26 HPC bags cryopreserved with 10% DMSO and intended for disposal were used. The Sepax-2 (Biosafe, Eysins, Switzerland) was evaluated using a sequential washing procedure. Outcomes were CD34+ cell recovery and viability after washing. RESULTS: The Ringer lactate supplemented or not with albumin 2·5-5% presented satisfactory results compared with HES solution in terms of CD34+ cell recovery and viability after washing. However, the apparition of aggregates led us to renounce to these alternative solutions. Using HES solution and a sequential washing of three bags, we showed the elimination of 95% of the DMSO, a postwash viable CD34+ cell recovery of 79·9 ± 9·4% and a total nucleated cell viability of 66·5 ± 9·3%. CONCLUSION: The preclinical evaluation of an automated sequential washing procedure for DMSO removal in thawed HPC grafts has proven to be effective and comparable to previously published data. Despite our attempt to find an alternative solution to the HES solution, more efforts should be done on this side to reach a consensus on cryopreservation protocols.

[Proteomics and transfusion medicine]. / Protéomique et médecine transfusionnelle.

The term "proteomics" covers tools and techniques that are used to analyze and characterize complex mixtures of proteins from various biological samples. In this short review, a typical proteomic approach, related to the study of particular and illustrative situation related to transfusion medicine is reported. This "case report" will allow the reader to be familiar with a practical proteomic approach of a real situation, and will permit to describe the tools that are usually used in proteomic labs, and, in a second part, to present various proteomic applications in transfusion medicine.

Microparticles in stored red blood cells: an approach using flow cytometry and proteomic tools.

BACKGROUND AND OBJECTIVES: Microparticles (MPs) are small phospholipid vesicles of less than 1 microm, shed in blood flow by various cell types. These MPs are involved in several biological processes and diseases. MPs have also been detected in blood products; however, their role in transfused patients is unknown. The purpose of this study was to characterize those MPs in blood bank conditions. MATERIALS AND METHODS: Qualitative and quantitative experiments using flow cytometry or proteomic techniques were performed on MPs derived from erythrocytes concentrates. In order to count MPs, they were either isolated by various centrifugation procedures or counted directly in erythrocyte concentrates. RESULTS: A 20-fold increase after 50 days of storage at 4 degrees C was observed (from 3370 +/- 1180 MPs/microl at day 5 to 64 850 +/- 37 800 MPs/microl at day 50). Proteomic analysis revealed changes of protein expression comparing MPs to erythrocyte membranes. Finally, the expression of Rh blood group antigens was shown on MPs generated during erythrocyte storage. CONCLUSIONS: Our work provides evidence that storage of red blood cell is associated with the generation of MPs characterized by particular proteomic profiles. These results contribute to fundamental knowledge of transfused blood products.

[Efficacy of oral administration of a micellaar solution of vitamin K during the neonatal period]. / Efficacité de l'administration orale d'une solution micellaire de vitamine K en période néonatale.

BACKGROUND: Oral administration of vitamin K to neonates is quite satisfactory for preventing hemorrhagic disease of the newborn. The aim of this study is to test efficacy of a micellar solution of vitamin K at birth. POPULATION AND METHODS: Thirty full term infants, exclusively breast-fed during the first month of life, were included in this study. Seven of them (control group Cos) were given oral supplementation with 5 mg vitamin K1, cremophor; 15 other infants were given oral supplementation with 3 mg micellar solution of vitamin K1 (group MMos) and 7 were given an intramuscular injection of 1.5 mg micellar solution of vitamin K1 (group MMim). Prothrombin time activity and plasma vitamin K concentration were measured in the cord blood, 24 +/- 12 hours and 1 month after supplementation. RESULTS: No hemorrhage was seen and tolerance to vitamin K was good in the 3 groups. Mean prothrombin time activity was 54% in the cord blood, around 55% and 75%, 24 hrs and 1 month after supplementation, respectively; only one infant had low value (41%) by 1 month despite normal plasma vitamin K concentration. Two infants had low plasma vitamin K1 concentration by the second control despite normal prothrombin time activity; one belonged to the MMos group and the other to the Cos group. Mean values of plasma vitamin K1 concentration were higher by 1 month in the MMos group. CONCLUSION: A unique dose of micellar solution of vitamin K given orally at birth seems effective to prevent hemorrhagic disease.

The pattern of regional cerebral blood flow during alcohol withdrawal--a single photon emission tomography study with 99mTc-HMPAO.

Cerebral blood flow was investigated during alcohol withdrawal in 15 male alcoholics by single photon emission computerized tomography with 99mTc-HMPAO and compared with the results of a second study 3 weeks later when all symptoms of withdrawal had disappeared and when the patients had been free of medication for at least 1 week. Slice images were reconstructed parallel to the orbitomeatal plane, and tracer activity was analyzed in 8 regions of interest per hemisphere. During alcohol withdrawal a special pattern of cerebral blood flow distribution could be observed. Relative perfusion was elevated in both inferior temporal regions, whereas it was reduced in the superior temporal region of both hemispheres. The changes of cerebral blood flow distribution did not correlate with neuropsychological findings nor with the severity of withdrawal syndrome.