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Biomedical subjects

G Follea

Publications and source records attributed to G Follea.

30 records · Page 2Linked to original sources

Simultaneous enzymo-immunologic assays of platelet associated IgG, IgM and C3. A useful tool in assessment of immune thrombocytopenias.

A solid phase enzymo-immunologic assay (EIA) has been developed to measure platelet associated (PA) IgG, IgM and C3. Washed platelets are mixed with a goat anti-IgG (IgM or C3) antiserum and then incubated in serum coated polystyrene plates. There is an inverse relationship between the level of PA IgG (IgM or C3) and the amount of goat antibodies binding to the IgG (IgM or C3) coating the plates. These goat antibodies are detected by addition of a phosphatase-labelled sheep anti-goat immunoglobulins antibody followed by a substrate giving a colour reaction. Using this technique, platelets from normal donors gave values of 2.04 +/- 1.10 fg IgG/platelet (mean +/- SD), 8.66 +/- 2.61 x 10(-16) g IgM/platelet and 5.67 +/- 2.63 x 10(-16) g C3/platelet. In 35 thrombocytopenic ITP patients we observed an increased level of PA IgG in 25, of PA IgM in 24 and of PA C3 in 23, and all of them had at least an increase of one of the 3 components. In 10 ITP patients in remission, 2 had an increased level of PA IgG while PA IgM and C3 values were normal in all. On the other hand, 2 non thrombocytopenic patients with systemic lupus erythematosus had an increased level of PA IgM. Compared to the standard antiglobulin consumption assay (ACA), the EIA was simpler to perform and more sensitive.

Blood Platelets↗

[Lupus anticoagulant screening: comparison of 5 tests (author's transl)].

Five tests were carried out on 15 lupus anticoagulant plasmas: activated partial thromboplastin time with a commercial reagent (APTT); kaolin partial thromboplastin time with a human brain extract (KPTT-H); tissue thromboplastin inhibition test (TTI); Russell's viper venom time without phospholipid (RVVT); assay of phospholipid-related procoagulant activity (PPA). One of our criteria for diagnosis of lupus anticoagulant was a prolonged APTT; hence this test was abnormal in all 15 plasmas. An abnormal TTI was observed for the 15 lupus anticoagulants while PTT-H was abnormal in only 13 cases, RVVT in 11 cases and PPA assay in 12 cases. In another study evaluating the specificity of TTI and PPA assay, the TTI appeared to be influenced by factor II, V, VII, and X deficiencies, but not by factor VIII: C, IX, XI, and XII deficiencies, or by anti-factor VIII: C anticoagulants. Furthermore, the TTI displayed a weak sensitivity to heparin. On the other hand, the PPA assay was influenced by anti-factor VIII: C anticoagulants of high potency and was found to be more sensitive to heparin than the TTI. Our overall results emphasize the value of TTI as a screening test for the lupus anticoagulant.

Blood Coagulation↗

[Antiplatelet drugs (author's transl)].

Acetyl salicylic acid, sulfinpyrazone, dipyridamole, hydroxychloroquine, ticlopidine, clofibrate, nicergoline are the most used antiplatelet drugs. A. S. A. and sulfinpyrazone have been tested in several large scale clinical trials. A. S. A. seems beneficial in the prevention of cerebral ischemia for patients, specially men who have previously had a transient cerebral ischemic attack. Sulfinpyrazone appears to be effective in reducing cardiac deaths during the first year after myocardial infarction.

Aspirin↗

Antithrombin III deficiency in diabetes mellitus: influence on vascular degenerative complications.

Plasma Antithrombin III (At III), a natural inhibitor of coagulation, was determined using a single radial immunodiffusion technique. In 116 diabetics, plasma At III levels were significantly decreased (26.6 +/- 0.4 mg/100 ml) compared with those in 64 controls (31.0 +/- 0.3 mg/100 ml, P less than 0.001). An elevation of plasma fibrinogen degradation products in 42 per cent of our patients, and a positive linear relationship between platelet counts and At III levels ( r = 0.29, P less than 0.01), provided additional evidence for chronic disseminated intravascular clotting in diabetes mellitus. Diabetic retinal complications were more frequent in patient with low plasma At III levels (50.6 per cent of cases) than in those exhibiting At III concentrations within a normal range: 32.4 per cent of cases (X2 = 6.09, P less than 0.02). It is postulated that the low levels of At III encountered in diabetes result from excessive consumption, and that the deficiency may be responsible for the onset and/or aggravation of intravascular clotting. At III deficiency may therefore contribute to vascular degenerative complications, particularly those leading to diabetic retinopathy.

Adolescent↗

A multicenter study on the efficiency of white cell reduction by filtration of red cells.

To evaluate accurately the current performance of filtration, the French Produits Sanguins Labiles study group, composed of 21 transfusion teams, conducted a large-scale 6-month study involving over 1400 filtrations and 3000 controls. Some 745 standard red cell concentrates (RBC concentrates) and 690 concentrates previously white cell (WBC)-reduced by removal of buffy coat (BC-poor RBC concentrates) were filtered using six commercially available filters: at least 170 results were collected per filter, spread among a minimum of three teams. Prefiltration controls show that the removal (manual and automated) of the buffy coat results in an initial WBC reduction of approximately 63 percent, along with a hemoglobin loss of 4 g (7%). After filtration, residual WBCs were counted in the Nageotte manual counting chamber. The reliability of this counting method, which is simple and adapted to low WBC concentrations, was characterized in this study by a 25-percent coefficient of variation (CV) for a concentration of 2.5 WBCs per microL (i.e, 0.6 x 10(6) WBCs/filtered unit). The analysis of the results shows that, for five of six filters (1 filter was excluded), the postfiltration median value of residual WBCs was 1.1 x 10(6) in filtered RBC concentrates (n = 590), whereas it was 0.34 x 10(6) in filtered BC-poor RBC concentrates (n = 581). The difference is significant (p less than 10(-8), Wilcoxon test). Hemoglobin loss due to filtration varies according to the filter, from 5.7 +/- 2.2 to 17.3 +/- 2.5 g.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Component Removal↗

[Luminex technology for HLA typing by PCR-SSO and identification of HLA antibody specificities].

Luminex technology is a new flow cytometry technology enabling us to analyse numerous reactions in a unique tube or well. It is a multiplexed data acquisition and analysis platform of microsphere-based assays that performs simultaneous measurements of up to 100 different analytes. In the histo- compatibility field, individual sets of microspheres are modified with reactive components such as antigens in order to perform HLA antibodies identification, or with oligonucleotides in order to perform HLA typing after reverse PCR-SSO. Thus microspheres are the equivalent of a panel of HLA typed lymphocytes (for PRA determination and antibody identification) or equivalent to a large set of probes selected to assign HLA typing. This new tool can be very useful in HLA laboratories since it is very easy to use and the results are concordant with those obtained with reference technics.

Antibodies↗