[Attempt to adapt measurement of serum iron levels to the Centrifichem with a direct method using bathophenanthroline sulfonate-guanidine. Value and limits]. / Essai d'adaptation du dosage du fer sérique sur Centrifichem par une méthode directe à la bathophénanthroline sulfonée-guanidine. Intérêt et limites.

The authors have studied a direct automated colorimetric determination of iron serum on Centrifichem. Accuracy and linearity are the same than these obtained by the SFBC recommended method. Precision is poor: the coefficient of variation is about 15% for low values. No alteration in the absorbance is recognized by bilirubin, even in the serum which contains 342 mumol.l-1 of bilirubin. The value of serum iron increases significantly as hemoglobin and copper are added to the serum.

[Detection of hyperamylasuria. Value of a quick test]. / Dépistage d'une hyperamylasurie. Intérêt d'un test rapide.

A new reactive strip was used in a hospital admission unit, to detect amylasuria in the urine of 76 patients consulting for abdominal pain (population A) and of 68 unselected patients (population B). Detection on admission by this method was concordant with subsequent laboratory detection in 93% of the cases. The fast test was positive for amylasuria in 17 patients: 13 (17.1%) in population A and 4 (5.9%) in population B. The 8 patients recorded as "+" had moderate amylasuria with multiple but ill-defined symptoms mostly abdominal. The 9 patients recorded as "++" had marked amylasuria highly suggestive of an abdominal disease, including 4 cases of chronic pancreatitis.

Continuous assay of serum 5-nucleotidase activity with inosine 5'-monophosphate as substrate and total automation using a transfer-analyzer (Kem-O-Mat).

The continuous spectrophotometric assay of 5'-nucleotidase originally described by Heinz et al. ((1980) J. Clin. Chem. Clin. Biochem. 18, 781-788) was modified and fully automated on a Kem-O-Mat transfer analyzer, using inosine 5'-monophosphate as substrate. The reaction product was hydrogen peroxide and the reduction of NADP was observed for 10 minutes at 340 nm and at a reaction temperature of 30 degrees C. The different factors involved in the enzyme reaction were checked, including the substrate concentration, reaction rate, linearity and substrate preservation. Normal values ranged from 1 to 13 U/l. Between-day reproducibility was estimated with two different commercial control sera, and the coefficient of variation was 5% for the upper limit of normal activity (23 U/l). There was good agreement between the present method and a semi-automatic colorimetric technique (for 100 sera tested by both methods, the correlation coefficient was 0.974 and the regression line equation, y = 0.85 x- 1.5). Despite the lengthy reagent mixture preparation procedure, the method permitted assay of 50 samples per hour. The occurrence of high serum blanks in certain pathological states is discussed.

[Determination of alpha-1-foetoprotein in human serum by electroimmuno-diffusion on agarose (author's transl)]. / Dosage de l'alpha-1-foetoprotéine sérique par electroimmunodiffusion sur agarose

The electroimmunodiffusion on agarose has been applied for the determination of AFP in human serum. The proposed method can be used for concentrations between 0.6 and 50 mg/l; the reproducibility was judged to be acceptable. For concentrations higher than 10 mg/l, a good correlation was observed between electroimmunodiffusion and radial immunodiffusion.

[Total serum iron-binding capacity: problems posed by the use of commercial control sera]. / La capacité totale de fixation du fer par le sérum: problèmes posés par l'utilisation des sérums de contrôle du commerce

After recalling the conditions of fixation of iron on human native serum, the authors determined the TIBC on 15 commercial control sera after titration. The transferrin concentration was determined on 13 sera of human origin, by two immunochemical techniques. They were thus able to demonstrate certain sera including a chelator substance other than transferrin, their TIBC depends only on the experimental conditions; such sera are not usable for quality control. Lyophilisation seems to reduce the reactivity of sites of fixation. It is thus necessary to provide a large excess of iron and prolong the duration of contact.