Les pièges de l'antibiogramme

The disk method and, more and more often, automated methods are used for antimicrobial susceptibility testing. Standardisation, automation and computerisation allow to reduce significantly technique errors. However, in his daily practice, the microbiologist must deal with difficulties in the interpretation of in vitro susceptibility testing. These difficulties are due to the bacteria's versatility and to the inability of certain methods to detect in vitro resistance mechanisms. Expert systems and a good knowledge of the methods used are necessary to help the microbiologist.     

Tumeurs à cellules claires des glandes salivaires: problèmes diagnostiques

Salivary gland tumors with a dominant population of clear cells present problems in differential diagnosis. They constitute a large group of tumors: clear cell myoepithelioma, clear cell oncocytoma, mucoepidermoid carcinoma, acinic cell carcinoma, epithelial-myeopithelial carcinoma, hyalinizing clear cell carcinoma, clear cell myoepithelial carcinoma, sebaceous tumors and metastatic renal cell carcinoma. These clear cell salivary gland tumors generally require special stains and often immunohistochemistry, for example to identify myoepithelial cell proliferation.     

Les problèmes actuels du contrôle antidopage équin

Horse race as well as human dope testing are currently progressing and detection capabilities of laboratories must improve accordingly. Biomolecules such as Erythropoietin and Growth Hormone are up to date doping agents which break the integrity of racing and welfare of horses. New improvements of mass spectrometry allow detection of small concentrations of these peptides. Qualitative determinations can be performed when the structure of the hormone administered can be distinguished from the natural form. Selected indirect markers can also be used to detect abuse of growth hormone: these markers can be insulin growth factors (mainly IGF-1), binding proteins (IGFBP-3) and some bone markers such as osteocalcin. Encouraging results are already obtained but it is necessary to support and to encourage fundamental and applied research to maintain dope testing at the highest level.     

Actualisation du système de Bethesda

The Bethesda system is a system of terminology for reporting the results of cervical cytology. It has been developed since 1988 and is widely used in the US and has been recommended by the ANAES. This system has been updated in April 2001. The most important modifications are the following: the suppression of the category « satisfactory but limited by å, the reintegration of benign modifications in the normal category, « atypical squamous cells of undetermined significance å which have been named « atypical squamous cells å and subdivided in « atypical squamous cells of undetermined significance å and « cannot exclude high grade squamous intraepithelial lesion å and endocervical adenocarcinoma in situ which is now a separate entity. The low grade squamous intraepithelial lesions and high grade squamous intraepithelial remain unchanged. Recommendations have been proposed concerning automated review and ancillary testing.     

Différenciation de l'origine exogène ou endogène de produits dopants par l'analyse isotopique du carbone

Carbon isotope analysis by isotope ratio mass spectrometry (IRMS) has a great analytical potential in anti-doping control. Indeed, standard analysis based on the identification an quantification of molecules come up against the specific problem of endogenous compounds because no obvious diagnostic of illicit abuse of these compounds can be obtained from their presence or concentration in urine. After the separation of the molecules by gas chromatography, IRMS offers the possibility to distinguish between exogenous and endogenous origin by the precise determination of the 13C/12C (the two stable carbon isotope) ratio value of these molecules.A brief presentation of the continuous flow isotope ratio mass spectrometer instrumentation is made and the principle of the differentiation between exogenous and endogenous origin of doping compounds is presented. In particular, the important contribution of this technique for the detection of exogenous testosterone intake is detailed. The trend of this technique for other steroid hormones such as endogenous anabolic steroids or corticosteroids and the perspective of its development in anti-doping control are also evoked.