[Sweat testing: review of technical requirements]. / Recommandations pour l'exécution et l'interprétation du test de la sueur.

The sweat test, a quantitative measurement of chloride in sweat, remains a key laboratory test to support the diagnosis of cystic fibrosis. However, because of its delicate execution, sweat test result should be interpreted with biological, clinical and genetic arguments. The following guidelines which we propose, were established in order to harmonize the practices of the sweat test. They are elaborated in a consensual way by biologists from cystic fibrosis reference centers and/or from the working group "Sweat Testing" of the National College of Biochemistry Hospital praticiens, according to the current state of knowledge on the subject, the experiment of the biologists and the recommendations established in the United States and in the United Kingdom.

[The main protein on the surface of the normal fibroblast (author's transl)]. / La protéine principale de la surface du fibroblaste normal.

In a general review, the authors discuss present knowledge on the main protein on the surface of the normal fibroblast, fibronectin. The peculiarities of this glycoprotein (localisation at the level of the cell surface, importance of thiol groups in the structure and expression of certain of its properties, reduction of the cells transformed by oncogenic viruses) are considered. The relationships which they may present with a plasma protein, cold insoluble globulin, are discussed together with the important role which they seem to play in the phenomena of cell adhesiveness.

[Identification and assay of nonvolatile organic by capillary column gas chromatography]. / Identification et dosage des acides organiques non volatils par chromatographie en phase gazeuse sur colonne capillaire.

The assay of organic acids as trimethyl silyl isobutyl compounds by gas chromatography was described. The lyophilization was used instead the extraction by organic reagent of the classical methods. Our method avoids the loss of some hydroxylacids. The identification and the measurement of one organic acid need respectively 3 and 5 hours. Our method is currently used for the metabolic diseases diagnosis.

Biochemical problems caused by some cryoglobulins.

An unsuspected cryoglobulinaemia may be responsible for incorrect serum protein results and thus cause dysglobulinaemia to remain undetected. When cryoglobulins precipitate above laboratory temperature, they will be removed with the clot during centrifugation of the blood sample if they have not previously been suspected clinically or biologically. In the case of massive cryoglobulinaemia, one might find normal protein results but such results are incorrect and if only total protein estimation has been requested, dysglobulinaemia can remain undetected. However, if electrophoresis can also been carried out, a slight abnormality of the gamma globulin fraction might be observed and this ought to incite one to look for cryoglobulin by the usual method (i.e. at 37 degrees C), even in the absence of clinical evidence.