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Biomedical subjects

D Reviron

Publications and source records attributed to D Reviron.

At least 37 records · Page 2Linked to original sources

[Pseudo-Glanzmann thrombasthenia in the course of autoimmune thrombocytopenic purpura].

INTRODUCTION: Auto-immune thrombocytopenic purpura is associated with platelet anti-glycoprotein antibodies, particularly with anti-GPIIb/IIIa complex. Persistence of these antibodies sometimes leads to acquired auto-immune thrombopathy. EXEGESIS: We report the case of a woman treated by splenectomy for auto-immune thrombocytopenic purpura, who developed 5 years later an ecchymotic syndrome despite normal platelet count. High bleeding time and platelet aggregation defect in vitro were evidenced. Following the initial thrombocytopenia, anti-glycoproteins GPIIb/IIIa with lupus anticoagulant and benign monoclonal gammapathy were noticed. Platelet controls showed that hypoaggregant activity was secondary to the persistence of anti-GPIIb/IIa antibodies. CONCLUSION: This acquired auto-immune thrombopathy simulating Glanzmann's thrombasthenia was secondary to the persistence of platelet anti-glycoproteins GPIIb/IIIa.

Aged↗

HPA-10w(b) (La(a)): genetic determination of a new platelet-specific alloantigen on glycoprotein IIIa and its expression in COS-7 cells.

The heterodimeric complex glycoprotein (GP)IIb-IIIa, the fibrinogen receptor of platelets, carries numerous alloantigen systems. These polymorphisms are responsible for the immune response after transfusion or during pregnancy. In the latter case, the mother develops an antibody against an epitope present on fetal platelets, and this results in platelet destruction in the fetus. In this report, we describe the molecular characterization of a new alloantigen (La(a)) on GPIIIa responsible for neonatal alloimmune thrombocytopenia (NAIT). Using polymerase chain reaction (PCR)-single-strand conformation polymorphism (SSCP) and DNA sequencing, we found a point mutation (G to A) in a heterozygous state on the GPIIIa gene leading to amino acid substitution Arg to Gln at position 62 of the mature protein. Transient expression of GPIIb-IIIa complexes in Cos-7 cells using wild-type or mutated GPIIIa cDNA allowed us to demonstrate that this mutation was responsible for expression of the La(a) epitope.

Adult↗

Cadaver kidney transplantation: ethics and consent.

Organ transplantation began to develop soon after the Second World War. The constant progress made in organ transplantation has resulted in an increase in the number of operations carried out. The laws governing transplantation are often drawn up to deal with the de facto situation in a particular country. The study focuses on Guideline 1 adopted by 44th World Health Assembly (resolution WHA 44-25) concerning consent in cadaver kidney transplantation. The discussion of the question of consent is based on a comparative study of the laws regarding kidney transplantation in the countries of what is known as Greater Europe. The points of discussion presented are not offered with a view to advocating a system where soliciting the consent of the family would be considered as ethically necessary. Given the current legal constraints, the presumed consent procedure, with consultation of the family would appear to be more appropriate.

Cadaver↗

HLA-DRB1 alleles associated with rheumatoid arthritis in southern France. Absence of extraarticular disease despite expression of the shared epitope.

OBJECTIVE: Extraarticular rheumatoid arthritis (RA) is almost unknown in Marseille in southern France. We investigated whether this was due to rare expression of the HLA-DRB1 shared epitope. METHODS: HLA-DRB1 alleles were characterized in 73 patients with RA and 108 controls by polymerase chain reaction amplification and oligonucleotide hybridization. RESULTS: In patients with RA, 76% expressed the shared epitope (46% DR1, 45% DR4). Four HLA-DRB1 alleles were positively associated with disease: DRB1*0101, DRB1*0401, DRB1*0404, DRB1*0405. Patients with double dose shared epitope had the most severe articular damage, but no extraarticular disease. CONCLUSION: In Marseille, 76% of patients with RA are shared epitope positive. Still, most do not develop extraarticular RA. This may be caused by the low frequency of HLA-DRB1*0401 in this population.

Adult↗

Neonatal thrombocytopenia in HLA-DR, -DQ, -DP-typed mother due to rare anti-HPA-1b (PLA2) (Zwb) fetomaternal immunization.

A new case of rare neonatal alloimmune thrombocytopenia, due to an IgG anti-HPA-1b in a mother HPA-1 (a+, b-), was diagnosed using monoclonal antibody-specific immobilization of platelet antigens. Clinically, it was similar to the 2 previously reported observations and confirmed that, in this particular case of anti-HPA-1b, the treatment with random platelet pools may be as effective as selected single-donor platelet units when maternal platelets are unusable. The HLA-DR, -DQ, -DP genotypes of the family were obtained by PCR-SSO. The mother's typing, compared to the HLA-DR of the 6 similar cases reported in Europe, suggests that a combined effect of two rare HLA haplotypes might enhance this immunization.

Adult↗

[HLA-DRB1 and HLA-DQB1 polymorphism in Algerians from Algiers].

The polymorphism of HLA-DRB1 and HLA-DQB1 genes in 100 unrelated Algerians from Alger was investigated using PCR amplification and oligonucleotide typing. Compared to western Europeans, this population shows a higher haplotypic frequency of HLA DRB1*03-DQB1*0201 (21.5%) and a lower haplotypic frequency of DRB1*0101-DQB1*0501 (2%). Two unexpected haplotypes are observed: DRB1*07-DQB1*0301 and DRB1*0406-DQB1*0402. DRB1*0402 is the most common subtype in the DRB1*04 group. Furthermore, we detected a rare DQB1*0305 allele, only found in a Sardinian subject until today.

Algeria↗

[Platelet group polymorphism in Provence. Comparison with the frequencies of platelet-specific allo-antigens observed in other populations].

Systems HPA-1 (Pla); HPA-3 (Bak) HPA-5 (Br) are involved in neonatal alloimmune thrombocytopenia and post-transfusion purpura. The frequencies of platelet-specific antigens in these three systems have been studied among one hundred one unrelated blood donors from Provence (South of France) for three generations. Typing was performed by the MAIPA test (monoclonal antibody-specific immobilization platelet antigen). The phenotypes frequencies found were: HPA-1a (PlA1): 97%; HPA-3a (Baka): 88.1%. These frequencies are quite similar to those reported in Europe and North America, but are different compared to Oriental and South American populations. Our Provence population has the highest frequency of HPA-5b (Bra) yet reported: 23.8%. These results define the polymorphism of platelet-specific antigens in the Provence population. Similar studies, among other populations, would provide new data for geographical haematology, which has so far been based on erythrocyte, leucocyte and serum polymorphisms. The variations between populations in these platelet-specific polymorphisms would be so many useful descriptive elements for the epidemiological study of associated diseases.

Blood Donors↗

[Not Available].

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Ethics, Medical↗

AIDS, a social dilemma: detection of seropositives.

At present, we can observe an evolution in ideas about the detection of HIV seropositivity through a qualitative analysis of specialised literature on the ethical aspects of AIDS. In the case of this disease, systematic screening of the population does not correspond to epidemiological criteria: it is wasteful, troublesome and costly. Whether it is voluntary, and therefore biased, or compulsory, and therefore controversial, systematic screening seems an unlikely option. This situation has prompted many versions of target-group screening, which correspond to two options: systematic screening of known risk-groups, discriminatory, confidential and anonymous; target-group screening linked to particular circumstances: recognised as necessary by blood-donors and well-accepted by pregnant mothers. This method can be institutionalised and applied in the armed forces and in prisons,.... Lastly, we consider measures taken by different countries and organisations.

Acquired Immunodeficiency Syndrome↗

Ethical problems raised by anti-HIV vaccination.

At present questions are being asked world-wide about the risk of the AIDS epidemic. The discovery of an anti-HIV vaccine has become an urgent priority, but it also raises a number of sensitive questions. Ethical problems in this field are particularly delicate, since the perspectives of individual health and public health do not seem to coincide. Our research team conducted a review of more than 400 articles on the ethical problems raised by AIDS. We concentrated particularly on the ethical and legal issues raised by research on anti-HIV vaccine. These problems fall into three main categories: therapeutic assays, which must be controlled by a strict agreement defined by international norms; manufacture of the future vaccine, raising legal difficulties which must be faced and solved now; distribution of the vaccine to the population, which should be conducted on a general basis, i.e. it should be offered to all individuals and not only to risk groups.

Animal Experimentation↗