[Study of the coverage of pollen capture in Lyon over three seasons (1999, 2000, 2001)]. / Etude de la couverture du capteur de pollen de Lyon sur trois saisons (1999, 2000 and 2001).

For the third consecutive year, the two sensors of the type HIRST of the National Network of aerobiology monitoring (RNSA) worked on the agglomeration of Lyon. The primary trap (Lyon 1) is located at 26 m height on a roof in southern zone of Lyon (district of Gerland), the second (Lyon 2) is located in northern zone of the city (district of Vaise) on a roof at 15 m height compared to the ground. The study of the daily variations of the pollinic counts over the first two years had shown a perfect parallelism for pollens of trees, Poaceae and Urticaceae. Only the curves of pollens of ambrosia presented different layouts between the two pollen traps. The study of this third year makes it possible to consolidate the proceeding results and to appreciate the value of the cover of a Hirst pollen trap in urban implantation within the framework of the allergo-pollinic monitoring.

Pyrolysis-gas-liquid chromatography with atomic emission detection for the identification of Corynebacterium species.

We report here the application of pyrolysis-gas chromatography followed by atomic emission detection (AED) for the characterisation of microorganisms. AED measured the quantity of carbon, sulfur and nitrogen in the molecules separated chromatographically. Twenty-three strains, representing eight Corynebacterium species, were tested in this preliminary study. Co-ordinate principal analysis grouped 11 strains in their respective species group. Most of the other strains appear randomly distributed, perhaps because these strains require additional nutrients. These preliminary results show that the method could be used as a tool for the taxonomic and perhaps the epidemiologic characterisation of bacteria.

[Lyme borreliosis, emergent disease linked with the environment]. / La borréliose de Lyme, maladie émergente liée à l'environnement.

After a short historical presentation of the discovery of the pathogen and its vector, the authors present the current data on bacterial and acarologic taxonomy. Then they describe their results to assess the mechanisms of circulation of the bacteria in the forests of Ile-de-France, particularly in the forest of Rambouillet. The combined study of abundance and infection frequency of the vectors, small mammals and cervids leads to the characterization of periods and areas of higher risk. The risk periods correlate with high density of I. ricinus nymphs. The risk areas correspond to those of high density of cervids. The role of reservoir of small mammals is confirmed, to the one of large mammals, so debated, is clearly demonstrated.

Gas chromatography-atomic emission detection for the measurement of isotopes. Application to bioequivalence studies.

This study was designed to demonstrate the ability of gas chromatography-atomic emission detection (GC-AED) to quantitatively measure amounts of labeled and unlabeled molecules when they are mixed together with both variable overall concentrations (labeled+unlabeled) and variable isotope ratios. To perform this study, simulations of bioequivalence trials were carried out using 13C stable isotopically labeled molecules (SIL) coadministered with the unlabeled drug to act as biological internal standards. Various methodological approaches are shown and different methods of calculation developed for the quantitative determination of both SIL and unlabeled molecules. The pharmacokinetic parameters experimentally obtained are quite in accordance with the target values and GC-AED appears to be a valuable alternative to mass spectrometry for this kind of trial with concomitant use of labeled and unlabeled molecules.

Comparison between gas chromatography-atomic emission detection and gas chromatography-mass spectrometry for the assay of propofol.

Quantitation by gas chromatography-atomic emission detection (GC-AED) is based on the intensity of the signal measured at a wavelength characteristic of an element, after atomisation by the plasma. This response depends only on the number of atoms of this element present in the molecule under investigation, and is independent of the structure of the molecule. This technique was used for the assay of propofol, and the estimation of its two metabolites, after calibration with standard solutions of pure propofol. The results were compared with those obtained by gas chromatography-mass spectrometry (GC-MS). Propofol was quantified with higher precision and accuracy by GC-AED than by GC-MS which exhibited larger residual values. Concentration assessment for two metabolites showed a better agreement with the theoretical value by GC-AED since the response depends only on the number of carbon atoms in each molecule.

Use of enzyme-labelled protein G assay for the detection of anti Borrelia burgdorferi antibodies in wild animal sera.

A modified ELISA was developed for the detection of anti-Borrelia burgdorferi (Bb) IgG antibodies in wild animal sera based on an Enzyme-Labelled-protein G Assay (ELGA). Microplates were coated with an extract of Bb sensu stricto strain (SVI) as antigen. Specific antibodies of the serum samples were detected by a peroxidase-labelled-protein G. Using comparative immunodiagnosis by means of a passive hemagglutination test (HA), ELGA was tested on 82 roe-deer blood samples. A correlation was found between the two methods (r = 0.66). Good reproducibility of titers was observed by ELGA technique. A minimal cross-reactivity was discovered with Leptospira. ELGA could facilitate the recognition of specific antibodies in collections of wild animal sera.

Detection of 13C labelled compounds by gas chromatography coupled to atomic emission detection--application to caffeine metabolites.

This paper illustrates the use of gas chromatography coupled to atomic emission detection (GC-AED) and of the stable isotope tracer 13C for the determination of drug metabolites. After administration of a parent drug labelled with 13C and extraction of the metabolites from the biological fluids, a 13C chromatographic profile is determined using the specific detection of the 13C atomic emission and subtraction of the 13C natural abundance. Thus, only the compounds which are metabolites with a 13C enrichment over the natural abundance are detected. [1,3,7 trimethyl-13C3]xanthine which is extensively metabolized by the liver is used as an example.

Determination of plasma testosterone by mass fragmentography using [3,4-13C]testosterone as an internal standard.

The combination of glass capillary gas chromatography--mass spectrometry is especially suitable for the recognition of compounds. The use of [3,4-13C]testosterone as internal standard, mass fragmentography and isotope ratio measurement have been applied to the quantitative determination of testosterone in plasma. This paper describes the method, using tert.-butyldimethylsilylmethoxime and di-heptafluorobutyrate derivatives. The calibration graph in isotopic dilution is examined. The results obtained are compared with the results obtained by radioimmunoassay. The sensitivity of the method is judged from the lower limit of detection: 4.5 pg. The precision, and inter- and intra-assay are calculated.

The 4-O-methylation pathway of catecholamines: search for an in vivo production of 3-hydroxy,4-methoxyphenylglycol (iso-MHPG).

The existence of 3-hydroxy,4-methoxyphenylglycol in biological fluids has been investigated. 4-Hydroxy,3-methoxy-phenylglycol (MHPG) and 3-hydroxy,4-methoxyphenylglycol (iso-MHPG) have been separated from each other by gas-liquid chromatography of their heptafluorobutyryl derivatives, using an electron capture detector procedure. Urines of normal subjects, of patients with secreting nervous tissue tumors and human cerebrospinal fluids were analyzed. Iso-MHPG was never detected, with the exception of trace amounts in one urinary sample from a patient with a peculiarly high excretion of MHPG. It is concluded that norepinephrine is probably not 4-O-methylated in vivo, contrary to dopamine which is known to lead, at least to a small extent, to 4-O-methylated metabolites.