Mycobacterium xenopi and drinking water biofilms.

The ability of Mycobacterium xenopi to colonize an experimental drinking water distribution system (a Propella reactor) was investigated. M. xenopi was present in the biofilm within an hour following its introduction. After 9 weeks, it was always present in the outlet water (1 to 10 CFU 100 ml(-1)) and inside the biofilm (10(2) to 10(3) CFU cm(-2)). Biofilms may be considered reservoirs for the survival of M. xenopi.

Genomic DNA extraction from small amounts of serum to be used for alpha1-antitrypsin genotype analysis.

If laboratory diagnosis of alpha1-antitrypsin (alpha1-AT) deficiency is usually based on its phenotype identification by isoelectric focusing, alpha1-antiprotease inhibitor (Pi)S and PiZ genotypes can also be determined by deoxyribonucleic acid (DNA)-based methods. Recently, several methods have been described for preparing genomic DNA from serum. The aim of the current study was to determine the Pi allele from serum extracted DNA by polymerase chain reaction (PCR) and to compare these results with those obtained with whole blood extracted DNA. Serum alpha1-AT concentration and phenotypic identification were systematically performed in 43 hospitalised patients. Genomic DNA was simultaneously purified from whole blood and from serum. The mutation detection was found using a PCR-mediated site-directed mutagenesis method. Concerning phenotypic identification, 29 patients were MM homozygotes, 11 were heterozygotes for S (MS = 7) or for Z (MZ = 4) and three showed a ZZ phenotype. Genotyping analyses gave identical results with serum and whole blood extracted DNA and all the results were in agreement with the phenotyping results. The authors found that the deoxyribonucleic acid-based test proved to be a reliable tool for alpha1-antitrypsin deficiency diagnosis and appears to be an alternative for the labour intensive alpha1-antitrypsin determination by isoelectric focusing. The authors also concluded that this method yields good quality deoxyribonucleic acid from serum, equal to that extracted from whole blood and is helpful in retrospective studies of multiple genetic markers.

[Results of hemograms of a series of top-level cyclists: an example of a factor of biological variability]. / Résultats d'hémogrammes d'une série de cyclistes de haut niveau: exemple d'un facteur de variation biologique.

We report data about 50 caucasian top-level cyclists (45 males, 5 women, aged between 16 and 36 years, mean 25 +/- 4.5). Recruitment was by controlling top-level athletes in order to follow their blood cell counts to detect variation in haemoglobin concentration and hematocrit level (prevention of erythropoietin abuse). All samples were drawn in the morning, when the cyclists were at rest, according to a standardized protocol. Erythroblastic serie was abnormal in several cases (4 anaemias, 3 macrocytosis, 6 low haematocrit level, 10 mean cell haemoglobin higher than 32 pg, low reticulocyte count). White blood cells showed a trend toward low counts for neutrophils and lymphocytes. Two cyclists had platelets counts below 150.109/l. Our data indicated that top-level cyclism had some effects on the blood cell counts, which is likely to indicate an effect of intense aerobic training on physiological status.