[Evaluation of reticulocyte count on Cell-Dyn 3500 automate: comparison with a flow cytometry technique]. / Evaluation de la numération des réticulocytes sur automate Cell-Dyn 3500: comparaison avec une technique par cytométrie en flux.

Cell-Dyn 3500 automate (Abbott) provides reticulocyte count using a recent software, after ribosomal RNA colouring with methylene blue reagent. The aim of this study was to evaluate results from Cell-Dyn 3500, and to compare them with the routine laboratory technique by flow cytometry (FacScan, Becton-Dickinson). Cell-Dyn 3500 analytical parameters (inter- and intra-assay precision, sample-to-sample contamination) were good and in accord to manufacturer's specifications. Reticulocyte values from blood samples kept at 4 degrees C during 3 days were unchanged. Usual values in 145 normal patients were found between 71.3 and 78.3 G/l with Cell-Dyn 3500, between 119.3 and 130.2 G/l with FacScan. Both techniques were compared in 87 patients with various anemias: Cell-Dyn 3500 showed more frequently high reticulocyte values in regenerative anemias (hemorrhagic), but was less performant for classification of aregenerative anemias. Reticulocyte count with Cell-Dyn 3500 is a semi automatic, easy to perform and swift technique, using no toxic reagent but unitary test tubes kept at room temperature. The test cost is however high, and Cell-Dyn 3500 cannot be used during the analysis.

Gel-test: interpretation and value of a new technique for the detection of irregular antibodies.

Here we report on our experience with the use of a 'Gel-Test' (DiaMed-ID Micro Typing System) technique for the detection and identification of irregular antibodies in a general hospital. This easy-to-use, standardized technique poses the question of the impact of its sensitivity on the specificity of the results. Of the 10% of observed positive reactions, 3.7% were irregular antibodies, 3.8% papain auto-antibodies, 1% cold antibodies and 2% not elucidated. Two hundred and eighteen irregular antibodies identified and titred with the 'gel-test' system were tested in parallel by 'tube' method. Sixty-three of these antibodies (29%) were not detected by the 'tube' method. While anti-Kell was always detected by both methods, we found the following false natives with the tube method: 15% anti-D, 32% anti-E, 42% anti-Cw and 58% anti-Lea. 68% of these false negatives had a low titre. The immunoglobulin class of the anti-E was studied; the sensitivity of the 'gel-test' system was associated with IgM in the anti-E. The sensitivity and standardization of the 'gel-test' technique guarantee greater safety in blood transfusion and increase efficiency in the prevention of foeto-maternal stimulation of anti-D.

Comparative study of fluoride bioavailability following the administration of sodium fluoride alone and in combination with different calcium salts.

To assess whether an interval of a few hours would be advisable between an intake of sodium fluoride (NaF) and that of calcium salts when treating osteoporotic patients with vertebral collapse, we carried out three pharmacokinetic studies in 12 healthy fasting volunteer subjects to compare the fluoride bioavailability provided by NaF alone and NaF combined with two calcium salts. The results were as follows: (1) When NaF is accompanied by calcium, the fluoride peak level is lower and delayed. (2) Fluoride absorption varied greatly among individuals in both experiments, but none of the 6 subjects proved to be nonabsorbers. (3) The areas under the curves obtained with each of the three preparations were not significantly different, but 24-h urinary fluoride was significantly lower in volunteers receiving simultaneously NaF and calcium salts than in volunteers receiving only NaF.

[Determination of fibrinopeptide A (FpA): comparison of an enzymatic method and isotopic method with reference to ventilation-perfusion scintigraphy]. / Dosage du fibrinopeptide A (FpA): comparaison d'une méthode enzymatique et d'une méthode isotopique, en référence à la scintigraphie de ventilation-perfusion.

Fibrinopeptide A becomes free after thrombolysis of fibrinogen in thrombo-embolic situation. In view to quantify this molecule, the authors have compared two different methodologies (enzymatic and isotopic). Isotopic scintigraphy of lung (ventilation-perfusion) served as reference in this study for pulmonary thrombosis.

[Acquired toxoplasmic chorioretinitis with a late onset]. / Choriorétinite toxoplasmique acquise à révélation tardive.

Maternal toxoplasma infection was responsible for congenital toxoplasmosis with ocular and cerebral manifestations in the infant. The acquired character of the toxoplasmosis in the 5th month of pregnancy was confirmed by serologic data and isolation of the parasite from the placenta. Five years later, an evolutive chorioretinitis was found in the mother. The toxoplasma origin of the ocular injury was proven by the study of aqueous humor. This case report is compared with the rare similar cases in the literature. The late discovery of ocular impairment is discussed.

[Effect of 2-mercaptoethanol on immunoglobulin M in toxoplasmosis and rubella]. / Action du 2 mercapto-éthanol sur les immunoglobulines M de la toxoplasmose et de la rubéole.

2 mercapto-ethanol (2 M-E) can be used to demonstrate IgM immunoglobulins to both toxoplasmosis and to measles, but while the action of this reagent is easily confirmed in the course of agglutination reactions with toxoplasma, it is only straightforward in certain circumstances in the course of the inhibition of haemagglutination reaction with measles virus. The agglutination reaction is very sensitive for this group of immunoglobulins: the depolymerization of toxoplasmosis IgM by 2 M-E is well demonstrated in total serum. The inhibition of haemagglutination reaction is sensitive for IgM and IgG, but the much higher concentration of IgG often masks the immunological activity of the IgM; the depolymerization of measles IgM by 2 M-E is only barely demonstrated on the IgM fraction. The use of 2 M-E is also a valuable means of confirming the fractionation obtained by filtration chromatography.