Intérêt de la cytogénétique dans les syndromes lymphoprolifératifs chroniques

Chronic B-cell lymphoid proliferations are characterised by the presence of multiple recurrent chromosomal aberrations. A certain number of these chromosomal anomalies have been found to represent disease-specific tumour markers : the t(11;14) in mantle cell lymphoma, the t(14;18) in follicular lymphoma and the t(11;18) in lowgrade MALT lymphoma, for instance. These tumour-specific genetic markers are not only useful in patient diagnosis and follow-up, but can also have great prognostic significance. Recent prospective studies in chronic lymphocytic leukaemias have shown that in multivariate analysis, 17p and 11q deletions are the two strongest independant predictors of survival followed by age and RAI stage.The occurrence of common genetic changes in different categories of chronic lymphoid disorders is suggestive of common disease mechanisms in these apparently distinct disease entities. Therefore, it is to be expected that further multidisciplinary studies on these lymphomas would identify other potentially disease- or progression-specific chromosomal aberrations useful for accurate classification.Finally, cytogenetic studies coupled with FISH mapping have already proved instrumental in identifying hot spots of rearrangement in human cancer which in turn have served as chromosomal guides for the cloning of new genes important in oncogenesis or tumour progression.     

Intérêt de la biologie moléculaire dans le diagnostic des infections vlrales du système nerveux central

The use of PCR and hybridization for the detection of viral nucleic acids in cerebrospinal fluid (CSF) currently represents the most reliable method for the meningoencephalitis diagnosis due to herpes viruses, enteroviruses, JC polyomavirus and HIV-1 primary infection. The molecular tools are less suitable for the postinfectious encephalitis associated with a systemic viral infection such as neurologic complications of measles, rubella, influenza and varicella, The speed and high sensitivity allow earlier diagnosis and specific treatment. The monitoring of the antiviral therapy is assessed by the development of quantitative amplification assays in CSF or by a negative PCR result. The pattern mutations conferring resistance and the genetic variability of viruses (HIV-1, Dengue virus) could be determined from different locations in the genome. Theses methods performed over the past several years as research tools have now a large scale application with the commercialization of some tests. But before becoming the first line diagnostic test, PCR of CSF could be conducted with control quality and evaluated protocols for avoiding false positive and negative results.     

Intérêt du séquençage dans le diagnostic virologique : application au VIH et au VHC

Sequencing is an important tool for viral typing and is also used to analyse resistant genotypes. However, in current hospital practice, it is only used for HIV and HCV. In effect, it is important to monitor the genetic diversity of these two viruses as this has implications for diagnosis (antibody and viral genome detection), plasma RNA quantification and therapeutic strategy. Several methods exist for typing or genotyping. The standard method is still nucleotide sequencing followed by phylogenetic analysis. In addition, it is only by sequencing several regions of the genome that recombinant viruses can be identified in certain cases. The introduction of systematic sequencing of resistant HIV in medical virology laboratories will favour data accumulation. The available data have already served to establish decision-making algorithms that need to be continually adapted and updated with evolving knowledge and the appearance of new molecules.     

Intérêt des dosages d'insuline,peptide C et hémoglobine glyquée dans le suivi des patients diabétiques

The diagnosis of diabetes mellitus was established by WHO in 1985 and was reviewed by an international Expert Committee in 1997. The revised criteria of fasting plasma glucose for the diagnosis has been based on 7 mmol/L (1,26 g/L). Prevalence of diabetes mellitus should be enhanced in the next few years. Cost of diabetes due to its complications is about 93% of the total cost. Insulin and peptid C do not have any interest in diabetes mellitus survey. Glycated hemoglobin (HbA_1c) which reflects long term glycation is an objective and commonly used parameter for monitoring diabetes. DCCT results have shown the association between chronic hyperglycemia (tested with HbA_1c) and microangiopathies. Its utilization is a major part of the care of patients with diabetes mellitus.     

Évaluation du mercury 16 (nova biomedical) : application aux profils d'urgence et de routine sur sang total et urine en néphrologie

The aim of this work was to assess the performances of Mercury 16 (sodium, potassium, chloride, total CO₂, glucose, urea, creatinine and hematocrit on whole blood, plasma, serum, urine, dialysate and cerebrospinal fluid) in following critical situations: use without formation, use with minimal maintenance and short laboratory responses time (less than 5 min.) on whole blood and urine and on icteric samples. The results obtained on whole blood and plasma were quite similar and the correlations between Mercury 16 - whole blood, CX7 Delta (Beckman) and STKS (Coulter) before and after dialysis (30 patients) were highly significant. Considering the well known potential bilirubin interference on glucose, creatinine and blood urea nitrogen determinations, our study showed the insensitivity of Mercury 16 to bilirubin (concentrations up 200 μmol/L to 700 μmol/L as total bilirubin). The correlations between Mercury 16 and CX7 Delta in 42 urine were highly significant. Finally, considering the analytical specifications, the short and easy maintenance, the management of analytical and patient data and reagents, the turnaround time (less than 2 min. for all mesured tests), the possibility of a link (direct or via a specific station) to central laboratory system, Mercury 16 is well adapted to any critical care situations and so, to point care of testing, in agreement with GBEA and Société française de biologie clinique recommendations.     

Borréliose de Lyme: enquête épidémiologique réalisée dans un chenil du nord-est de la France

Two serological surveys on 210 dogs in 1991 and 245 dogs in 1992 confirmed the presence of LYME Borreliosis in a military kennel in in the French province of Champagne.This study was followed in 1993 by a study of ticks populations present on the Suippes ground and their infection with spirochetes. Four ticks of the species Ixodes ricinus harbored spirochetes. The identification of one of these strains by PCR revealed that it was Borrelia afzelii, the agent of acrodermatitis chronica atrophians in humans.The number of dogs in contact with the bacteria responsible for Lyme desease and the percentages of ticks harboring Borrelia-type bacteriae were smaller than in other areas in France. Preventive measures have been reinforcced. They include enhanced vector control ad information of physicians and exposed personnel.     

Intérêt de l'hémovigilance dans l'amélioration de la démarche diagnostique et dans la prévention des incidents transfusionnels liés à la contamination bactérienne des produits sanguins

Through the hemovigilance system implemented in France in 1994, 185 cases of transfusion reactions due to the bacterial contamination (TRBC) of blood components (BC) have been recorded over 5 years, thus confirming the frequency and severity of bacterial risks in transfusion medicine. Activation of the hemovigilance network and awareness raising among the virus actors involved (clinicians, nurses…) have made it possible to both prevent possible related TRBCs (due to the transfusion of a BC derived from the same donation) and improve case reporting. The first results obtained through the alert system thus developed have led the Agence Française du Sang to assess and better understand, in a joint study, transfusion-related risks as well as determine factors likely to prevent them. Continuous analysis, in real time, of the reported cases have improved prevention strategies at every stage of the transfusion chain, from blood collection to blood component transfusion.