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Biomedical subjects

P Rouger

Publications and source records attributed to P Rouger.

At least 55 records · Page 3Linked to original sources
PubMed1999

Screening for HBV, HCV and HIV genomes in blood donations: shortcomings of pooling revealed by a multicentre study simulating real-time testing.

This study was undertaken in order to determine whether screening of viremic blood donations by testing of pooled donor samples could constitute a technically feasible transfusional safety measure. A pilot study of real-time simulation, on a day-to-day basis, of screening of three viral genomes (hepatitis B virus (HBV), hepatitis C virus (HCV) and human immunodeficiency virus (HIV)) was conducted by five French Blood Centers on plasma samples collected from blood donors and studied within undiluted samples and within sample pools of various sizes. This study was carried out within time conditions compatible with the release of platelets. For the detection of HCV and HIV genomes, the five laboratories achieved a sensitivity that decreased with the size of the sample pool. Four were successful in detecting all undiluted samples. In the 1/10 diluted samples, four failed to detect one HIV or HCV sample. In the 1/100 diluted samples, all laboratories failed to detect one or more HIV or HCV samples. For HBV genome, no participating laboratories detected all of the samples of the panel, even undiluted samples, and the sample pooling considerably affected sensitivity. The improvement and standardization of assays needs to be attained, and training of laboratories appears to be a step crucial for routine screening of viral genomes in blood donations.

Blood↗
PubMed1999

[Risk management program in a health facility using a project approach: transfusion risk management].

Risk management in the hospital, which is one of the referentiels of the ANAES accreditation manual, may be considered on two levels. Firstly, risk management may be approached globally, in the same way as it is tackled in the accreditation process. Secondly, risk management may be more definite. A specific risk chosen in accordance with the priorities of a particular plan may be dealt with individually. In this respect, the tranfusion process allows the risk management method to be tested and developed. f1

Blood Banks↗
PubMed1999

[Quality in training].

Knowledge has become an essential resource in developed societies, and hence the role of training has become ever more important. Training is the basis of professional proficiency. This is of particular interest in a public service such as blood transfusion, which is rapidly developing. To remain competent, a professional must regularly update his (her) basic knowledge. This requires an efficient training support. To implement a quality assurance system in a training center, several factors must be considered: the choice of a reference system; the evaluation of the customer's needs; the control and the assessment procedures.

Blood Transfusion↗
PubMed1999

[Quality control of reactant lots at the Nation Blood Group Reference Center (CNRGS). Data for the year 1998].

The reagents used for blood group analyses are subject in France to the same regulations as other reagents. A file must be submitted for each reagent to the Agence française de sécurité sanitaire des produits de santé. Furthermore, each production lot must be checked by the Centre national de référence pour les groupes sanguins (CNRGS) for control before marketing. These controls allow a comparative quality assessment of the reagents. The investigation by the CNRGS of the problems encountered in the every day use of these products makes this quality control even more accurate.

Blood Banks↗
PubMed1999

[DNA polymorphism applied to paternity testing. Analysis of 877 cases].

Paternity testing is based on biological analyses that have drastically developed during the past 20 years. According to scientific developments, paternity testing was based on red blood groups studies, the analysis of red cell enzymes and plasma proteins polymorphisms, the typing of the HLA-A and B antigens, and the DNA polymorphism in its various forms. This study aims at comparing the various analyses so that each becomes a reference for the others, in order to determine (i) the acceptable level of the paternity probability evaluation, and (ii) the exclusion rules according to new technologies. The relative performances of the various combinations of tests is analyzed in this report, based on a study of 877 cases. Thanks to studies based on the gene amplification of micro-satellites, the efficiency of this technique has been proved: it is however necessary to identify the limits of the tests and to know how to deal with those cases which require further analysis. Beyond the most efficient biological analysis, it is very important to think about paternity testing as a process in which biological tests are only one step.

Adult↗
PubMed1999

No quantitative relationship between CR1 and Lutheran expression on erythrocytes: In(Lu) gene product is not a common regulator of CR1 expression on erythrocytes.

The density of CR1, the C3b/C4b receptor (CD35), on erythrocytes (E) (CR1/E) is genetically determined. However, the broad distribution of CR1/E within a given genotype suggests that other genetic elements might contribute to the regulation of CR1/E. In some pathological conditions, including systemic lupus erythematosus (SLE), AIDS and hemolytic anemia, CR1 deficiency parallels the severity of the disease. When compared to healthy individuals, an accelerated decrease in CR1/E in these patients has been demonstrated, but other mechanisms interfering with CR1 density regulation during erythropoiesis might also contribute. In exceptional circumstances, CR1/E can be dramatically decreased in healthy individuals by the effect of a regulatory gene, In(Lu), that switches off various surface molecules on E, the structure genes of which are located on four different chromosomes, suggesting a transcription regulatory role for In(Lu) gene products. The hypothesis that products of this gene could physiologically regulate the surface density of all these molecules has been tested by determining Lub density on E (Lub/E) using quantitative flow cytometry. Lub antigenic sites were then compared to CR1/E among healthy individuals of the different CR1 density phenotypes, SLE patients with and without CR1 deficiency, and an exceptional SLE patient totally lacking CR1/E and reticulocytes. No quantitative relationship was found between CR1 and Lub expression in either normal or pathological conditions. These data establish that In(Lu) products are not involved in normal or pathological CR1 density regulation.

Antibodies, Monoclonal↗
PubMed1999

[From malaria to post-transfusional malaria].

Malaria is still a blood transmissible disease, though its frequency is continuously decreasing in non endemic countries. In endemic areas, the number of infected subjects is either stable or increasing, depending on the involved country. Cases of imported malaria, particularly malaria due to Plasmodium falciparum, are increasing in France. In regard to prevention in blood donors, regulations aiming at excluding potentially contaminated donors were implemented with positive effects. Since 1994, no cases of malaria have been reported by the French organization of hemovigilance.

Animals↗
PubMed1998

Organization of the human RH50A gene (RHAG) and evolution of base composition of the RH gene family.

Human Rh (rhesus) antigens are expressed in the red cell membrane as a multi-subunit complex, the central core of which is presumably composed of a tetramer made of two Rh and two Rh50 protein subunits. The interaction between Rh and Rh50 polypeptides is thought to be crucial to the correct assembly and transport of the complex to the cell surface. Here, we show that the human RH50A gene (RHAG) is composed of 10 exons whose size and exon/intron junctions are well conserved compared to those of the RH genes. We have also analyzed the RH50A 5' flanking region where the transcription initiation site has been identified. These results conclusively establish that the RH50A and RH genes do belong to the same gene family. Moreover, we show that the RH50A and RH genes are embedded in different compositional genomic contexts (i.e., different isochores) that are likely to drive the evolution of these genes, the base compositions (G + C content) of which differ drastically. Finally, we propose a scenario in which an RH50-like gene is likely to have played a founding role in the evolution of the RH gene family.

Animals↗
PubMed1998

[Contribution of hemovigilance to immunologic safety of blood transfusions: assessment after 3 years].

The haemovigilance system has indirectly introduced three types of information: a more precise tally of accidents and risks (even if the total number of events remains difficult to assess); an evolution of the mode of collecting relevant information (even if, after 3 years, it has become important to define new objectives and collection procedures); the identification of the main causes of errors leading to immunological accidents allowing the elaboration of schemes pointing out the possible failures and critical points of the various processes, such as blood bag distribution, ABO control at bedside, the prescription of examinations prior to transfusion. The analysis of haemovigilance data has induced a number of important consequences, particularly clinical practitioners' awareness of blood transfusion risks; elaboration of reliable and documented tools for the training of professionals and the information of patients; implementation of corrective and preventive measures, particularly to reduce accidents due to ABO incompatibility. These haemovigilance data will provide more fruitful results when cross-analysed with data from the reactovigilance system which is being set up. Until then, they will largely be used to elaborate blood transfusion quality assurance standards.

ABO Blood-Group System↗
PubMed1998

[Final bedside verification: results of a national survey of reagents and devices used in France].

The national reference Center for blood groups checked samples of reagents and devices used in France for a definitive verification of pretransfusion ABO tests performed at the patient's bedside, as defined by French health authority regulations. The results of an initial inquiry was published in 1991. The new study shows no significant improvement of the quality of reagents and devices. This is a major concern considering the importance of ABO incompatibility in severe hemolytic transfusion reactions.

ABO Blood-Group System↗
PubMed1998

Heterogeneity of blood group RhE variants revealed by serological analysis and molecular alteration of the RHCE gene and transcript.

After testing red cells from 12 RhE variants with a panel of anti-E monoclonal antibodies (MoAbs), four patterns of reactivity were detected indicating that the MoAbs may recognize four distinct E epitopes designated epE1, epE2, epE3 and epE4. The variants were classified into four categories (cat EI to EIV) which carried epE1 and epE2, epE1 and epE4, epE1, epE3 and epE4, and all four epitopes, respectively. Molecular analysis of the transcripts and genomic DNA of the variants from cat EI, EII and EIII displayed three distinct genetic alterations. Cat EI variants exhibited a point mutation (T500A) in exon 4 of the RHCE gene that resulted in a Met167Lys substitution in the third extracellular loop of the RhcE protein. Cat EII variant carried a hybrid gene structure characterized by replacement of exons 1-3 (or 2-3) of the RHCE gene by their specific counterparts in the RHD gene. This latter variant was also associated with a weak expression of the RhC antigen. In cat EIII variants there was a partial DNA exchange of exon 5 sequences (nt 697 and 712) between the RHCE and the RHD genes, generating a hybrid Rh cE-D-cE protein carrying the Glu233 and Val238 substitutions. The serological and molecular studies of the RhE variants indicated that: (i) the RhE antigen is a mosaic composed of at least four epitopes and proline at position 226 is necessary but not sufficient for the full expression of the E antigen, (ii) the lack of RhE epitope(s) is associated with heterogenous molecular alterations of the RHCE gene, and (iii) amino-acids located on the third and fourth extracellular loops of the RhCE polypeptide are critical for some RhE epitopes expression.

Antibodies, Monoclonal↗
PubMed1998

Screening blood donations for viral genomes: multicenter study of real-time simulation using pooled samples on the model of hepatitis C virus RNA detection.

BACKGROUND: The systematic screening for several blood-borne viral genomes in blood donations is a complementary safety measure planned or discussed by the national authorities of several countries. STUDY DESIGN AND METHODS: To appreciate the feasibility of such screening using pooled samples, a multicenter study of real-time simulation has been performed on the model of hepatitis C virus (HCV) infection. Four blood transfusion center laboratories and two research and diagnosis laboratories simultaneously screened, by several HCV RNA polymerase chain reaction assays, a panel of plasma sample pools of different sizes (500, 100, and 10 samples), collected from HCV-infected or HCV-uninfected blood donors. One viremic plasma was introduced in each pool. HCV RNA was detected by in-house polymerase chain reaction procedures or by standardized manual or semi-automated polymerase chain reaction assays. RESULTS: The results indicate the feasibility of sample pooling, which renders the screening for viral genomes by molecular biology techniques applicable in the short term and the importance of the experience of laboratory personnel in the use of molecular biology tools. CONCLUSION: The improvement of standardized assays needs to be continued, and training of laboratory staff members appears to be a crucial step before systematic screening of blood donations for viral genomes by molecular biology techniques can occur.

Blood Donors↗