Search PubMed⌕ Search

Biomedical subjects

G Andreu

Publications and source records attributed to G Andreu.

At least 19 recordsLinked to original sources
PubMed2005

[West Nile virus (WNV): generalities and implications for blood transfusion].

West Nile virus (WNV) is an arbovirus (genus Flavivirus, Family Flaviviridae, transmitted to humans by mosquito bite. In most cases (80%), human infection remains asymptomatic. Severe central nervous system complications (encephalitis and meningoencephalitis) are rare. In the Old World, the virus circulation has been demonstrated in Asia, Australia, Africa, Middle East and Europe. Several outbreaks in humans have been described. Following its introduction into North America in 1999, WN virus has been responsible of a large number of human cases in USA and Canada. For the first time, viral transmission by blood products was clearly demonstrated in USA in 2002. In France, the presence of virus has been reported in the Southeastern departments since 1962. In 2003, the occurrence of humans cases at specific geographical foci urged the French National Blood Agency (etablissement francais du sang) to take preventive measures for evaluating the virus transmission risks.

Animals↗
PubMed2003

[The number of cell separators existing in France in 2003].

The "2002 Apheresis" Group was commissioned by the President of the Etablissement français du sang to carry out a study on the national stock of automated apheresis devices and think about a method to harmonize techniques. The objective was twofold: to facilitate the initiation of public procurement procedures as well as to streamline the stock and to match practices. The members of the "2002 Apheresis" group first carried out an inquiry based on a nationwide questionnaire. They analyzed and compared the performances of the various separators. They also consulted suppliers on their short-term (2 years) projects. They finally met all regional apheresis correspondents. The group was then able to make suggestions to organize this activity as a part of a national apheresis scheme. Lastly, they helped devising public procurement procedures for the coming two years. This group is going to obtain a long-term recognition with the creation of a "Collection Group" conducted by the Scientific and Medical directors board at the Etablissement français du sang.

Automation↗
PubMed2003

[Application of molecular biology to blood transfusion safety: the nucleic acid testing].

Nucleic Acid Testing (NAT) for HIV-1 and HCV has been introduced in France and became mandatory for all homologous blood donations since July 1st 2001 in addition to serology screening. Previously, a feasibility study led to the selection of 2 technologies : a TMA based assay (Chiron) uses the Procleix HIV-/HCV assay on pools of 8 samples and a PCR based assay from BioMérieux-Roche which is a combination of an RNA extraction system (NucliSens, BioMérieux) with a fully automated system for nucleic acid amplification and detection (Cobas Amplicor, Roche). This system uses the Cobas Ampliscreen HCV test v.2.0 and the The Cobas Ampliscreen HIV test v1.5, on 24 sample pools. Pooling was required because single-donation testing is not yet feasible, as a result of the limitations in automation available for all current NAT technologies. The two technologies were easily implemented and showed nearly the same detection limit for HCV RNA and HIV-1 RNA. During a one-year period, from July 1st 2001 to June 30, 2002, out of the 2.5 million donations tested, the NAT yield resulted in one HIV-1 RNA positive-antibody negative donation and one HCV RNA positive-antibody negative donation. Two HIV NAT positive-antibody negative donations were missed by minipool NAT because a very low viral load. Moreover, the NAT implementation did not impact on blood component availability, including platelet concentrates.

Blood Transfusion↗
PubMed2003

An international study of the performance of sample collection from patients.

BACKGROUND AND OBJECTIVES: Collection of a blood sample from the correct patient is the first step in the process of safe transfusion. The aim of this international collaborative study was to assess the frequency of mislabelled and miscollected samples drawn for blood grouping. MATERIALS AND METHODS: Hospitals in 10 countries provided data on sample error rates during a period of at least 3 months, including the last quarter of 2001. Mislabelled samples were defined as those not meeting local criteria for acceptance by the laboratory. Miscollected samples [wrong-blood-in-tube (WBIT)] were defined as samples in which the blood group result differed from the result on file from prior testing. WBIT rates were corrected for the proportion of repeat samples and for undetectable errors occurring as a result of chance collection of blood from the wrong patient with the same ABO group. Participants also completed a questionnaire on current policies regarding sample collection. RESULTS: A total of 71 hospitals completed surveys describing policies related to sample collection. Sixty-two hospitals provided usable data on the frequency of mislabelled and miscollected samples. Mislabelled and miscollected samples were common. Based on results from over 690,000 samples, the median hospital performance resulted in a rate for mislabelling of 1 in every 165 samples (6.1 per 1000; interquartile range 1.2-17 per 1000). The presence of national patient identification systems in Sweden and Finland was associated with rates of miscollected samples that were too low to estimate. Outside these nations, miscollected samples demonstrating WBIT occurred at a median rate of 1 in every 1986 samples (0.5 per 1000; interquartile range <0.3-0.9 per 1000). There was great variation worldwide in the reported frequency of mislabelled samples, probably resulting from variation in policies for sample acceptance. Miscollected samples occurred at a more constant rate. CONCLUSIONS: The rate of mislabelled samples and miscollected samples is 1000-10,000-fold more frequent than the risk of viral infection. Rates of mislabelled samples and WBIT can be tracked as key indicators of performance of an important step in the clinical transfusion process. WBIT episodes represent important 'near-miss' errors. By providing baseline performance data for the collection of patient blood samples, this study may be useful in formulating future national standards of performance for sample collection from patients.

Blood Group Incompatibility↗
PubMed2002

[Blood donation].

Explore the source record for details and available documents.

Blood Component Transfusion↗
PubMed2002

Quality control of leucoreduced cellular blood components in France.

BACKGROUND AND OBJECTIVES: Since 1 April 1998, all cellular blood components in France have been leucoreduced. The current French standard is < 1 x 10(6) white blood cells (WBC) per unit with a 95% confidence that at least 97% of units will meet this standard. MATERIALS AND METHODS: Quality control (QC) data for leucoreduced cellular blood components were collected from the 41 French blood centres over a 5-month period. Conformance to the standard was determined using a non-parametric approach. RESULTS: More than 98% of the 15 286 red cell concentrates and of the 2895 platelet concentrates tested had < 1 x 10(6) WBC per unit. One filtration device gave unsatisfactory results and its use was discontinued. CONCLUSION: This QC survey shows an overall compliance with the standard. The data illustrate the practical value of identifying devices or centres with consistent QC problems.

Adult↗
PubMed2000

Ex vivo expansion of CD34-positive peripheral blood progenitor cells from patients with non-Hodgkin's lymphoma: no evidence of concomitant expansion of contaminating bcl2/JH-positive lymphoma cells.

The aim of the present study was to evaluate the capacity to expand of hematopoietic stem cell (HSC) samples from eight patients with NHL, and to follow in parallel the fate of tumor cells in four of eight samples still containing bcl2/JH+ tumor cells after CD34+ or CD19-/20-/34+ cell selection. The presence of bcl2/JH+ cells was also investigated after expansion in four of eight samples, two of which were bcl2/JH at harvesting and two which were initially bcl2/JH+ but became bcl2/JH (below the level of PCR detection) after cell selection, to assess a possible reappearance of occult tumor cells after expansion culture. We used culture conditions that we previously had established to allow high level expansion of normal precursors, progenitors and LTC-ICs. In this study, particular attention was given to the role of Flt3-ligand, known to favor the growth of B cells. The expansion conditions were: 1.5 x 10(3) cells/ml in serum-free medium containing stem cell factor (SCF), interleukin-3 (IL-3), IL-6, granulocyte-stimulating factor (G-CSF), erythropoietin (Epo) +/- Flt3-ligand (Flt3-L) for 10 days. After culture, total cells, CFU-GMs, BFU-Es and LTC-ICs were expanded to a mean of 833-, 6.6-, 4.6-, and 1.8-fold, respectively with the cocktail of cytokines not including Flt3-L. When Flt3-L was added, the mean expansion values were 1095-, 31-, 15- and three-fold, respectively. Residual bcl2/JH+ cells present in four of eight samples before expansion were not detected after expansion. Similarly, no tumor cells reappeared after expansion of the two samples which had become negative after selection, as well as in the two samples which were bcl2/JH- at harvesting. These results suggest first that ex vivo expansion of hematopoietic stem cells in patients with non-Hodgkin's lymphoma is feasible without incurring the parallel risk of amplifying tumor cells; second, that Flt3-L did not stimulate the growth of tumor cells while it clearly favored the growth of normal progenitors.

Adult↗
PubMed1999

Activation of the Janus kinase 3-STAT5a pathway after CD40 triggering of human monocytes but not of resting B cells.

CD40/CD40 ligand interactions play a key role in the immune responses of B lymphocytes, monocytes, and dendritic cells. The signal transduction events triggered by cross-linking of the CD40 receptor have been widely studied in B cell lines, but little is known about signaling following CD40 stimulation of monocytes and resting tonsillar B cells. Therefore, we studied the CD40 pathway in highly purified human monocytes and resting B cells. After CD40 triggering, a similar activation of the NF-kappaB (but not of the AP-1) transcription factor complex occurred in both cell preparations. However, the components of the NF-kappaB complexes were different in monocytes and B cells, because p50 is part of the NF-kappaB complex induced by CD40 triggering in both monocytes and B cells, whereas p65 was only induced in B cells. In contrast, although the Janus kinase 3 tyrosine kinase was associated with CD40 molecules in both monocytes and resting B cells, Janus kinase 3 phosphorylation induction was observed only in CD40-activated monocytes, with subsequent induction of STAT5a DNA binding activity in the nucleus. These results suggest that the activation signals in human B cells and monocytes differ following CD40 stimulation. This observation is consistent with the detection of normal CD40-induced monocyte activation in patients with CD40 ligand+ hyper IgM syndrome in whom a defect in CD40-induced B cell activation has been reported.

B-Lymphocytes↗
PubMed1999

Generation of phagocytic MAK and MAC-DC for therapeutic use: characterization and in vitro functional properties.

Phagocytic cells with macrophage or dendritic cell phenotype, able to capture and ingest tumor cells, were derived in large numbers from peripheral blood mononuclear cells using two different activation procedures. Peripheral blood mononuclear cells were stimulated in nonadherent conditions in the presence of human AB serum with either granulocyte-macrophage colony-stimulating factor and dihydroxy-vitamin D3 for 7 days and with interferon-gamma for the last 18 hours to obtain activated macrophages (MAK) or with granulocyte-macrophage colony-stimulating factor and interleukin-13 for 7 days (with fresh interleukin-13 added on day 4) to obtain macrophage-dendritic cells (MAC-DC). A strong ability of MAC-DC to phagocytose yeasts was observed, in contrast to a low-intermediate phagocytosis capacity by MAK. Both CD14+ FCgammaR+ (FcgammaRI/CD64, FcgammaRII/CD32, FcgammaRIII/CD16) MAK and CD1a+/CD86+, CD14- MAC-DC were able to phagocytose whole tumor cells. However, only MAK phagocytosis was enhanced by FcgammaR engagement. MAK but not MAC-DC could lyse tumor cell in antibody-dependent cell cytotoxicity assays, via FcgammaRI. Thus, MAK as well as MAC-DC may represent valuable tools for different in vivo therapy strategies that do or do not include the use of monoclonal antibodies.

Antibody-Dependent Cell Cytotoxicity↗
PubMed1999

[Retrospective study of exchange transfusion for newborn infants with reconstituted blood. Review of 60 exchanges].

PURPOSE: The necessity of saving blood products has established the practice of exchange transfusion (ET) with reconstituted blood in newborns. The aim of this retrospective study was to evaluate the indications and the practice of this technique at the Perinatal Hemobiology Centre (Paris, France). METHODS: The records of intervention allowed us to review the etiologic categories for neonates having undergone exchange transfusion with reconstituted blood, the dosages used (bilirubin, hemoglobin), and the other main parameters of ET. RESULTS: Sixty ETs were performed in 48 newborns between the 1st July 1996 and the 1st July 1998. Twenty-seven with Rh hemolytic disease had 39 ETs (19 for hyperbilirubinemia, 12 for anemia, and eight for both), whereas ten out of 12 repeated ETs were indicated for hyperbilirubinemia (six of these cases were in newborns weighing > or = 2500 g and after a volume exchange < or = 1 blood mass [range 0.72-1.0] at the last ET). Twenty-one cases showed other diseases: six of them had anemia, nine had hyperbilirubinemia, and seven showed disseminated coagulopathy. The tolerance of ET was poor in 24% infants in this group. CONCLUSIONS: The volume of 1.3 blood mass for ET is sufficient for the majority of cases with hyperbilirubinemia, allowing transfusional savings in comparison with the previous recommendation of two blood volumes. Exact labeling of the content of units of packed red cells and plasma is essential to fulfill the volume and hematocrit requirements in every case.

Anemia↗