Détermination de la tortuosité pour la détection des rétinopathies vasculaires sur les images d''angiographie rétinienne

Les rétinopathies vasculaires peuvent être accompagnées d'une modification de la forme des vaisseaux. Les patients atteints courent le risque de perdre la vue. Jusqu'ici, les méthodes utilisées par les ophthalmologistes pour analyser ces modifications sont qualitatives. Nous proposons une méthode nouvelle d'analyse de la tortuosité des vaisseaux de la rétine en vue d'élaborer par la suite un outil d'aide au diagnostic des rétinopathies vasculaires. La première étape de la méthode est une représentation symbolique de la structure vasculaire de la rétine. La deuxième étape appelée reconstitution 2D est la classification des entités vasculaires en gros vaisseaux (artères ou veines) et en petits vaisseaux (artérioles ou veinules) en utilisant la moyenne du diamèetre et du niveau de gris des segments de vaisseau comme paramètres discriminants. La dernière étape consiste à calculer l'excentricité des vaisseaux pour décrire leur tortuosité. Pour s'assurer de la capacité de l'excentricitéà décrire les petites modifications de forme, un second paramètre a été défini à titre comparatif. Les résultats obtenus permettent de quantifier les modifications de forme des vaisseaux.     

Prevalence of hepatitis B virus DNA in anti-HBc-positive/HBsAg-negative sera correlates with HCV but not HIV serostatus.

BACKGROUND: Hepatitis B virus (HBV) DNA often remains detectable in serum despite clinical recovery and loss of HBsAg. OBJECTIVE: To study whether coinfection with HIV and HCV influence the chance of detecting HBV DNA in sera with markers of past hepatitis B. STUDY DESIGN AND RESULTS: The test panel included 160 anti-HBc-positive/HBsAg-negative sera collected in the diagnostic setting. The following parameters were determined in the sera: anti-HIV (32% positive), anti-HCV (34% positive), HCV RNA (18% positive), and anti-HBs (37% positive). A highly sensitive PCR (90%-detection limit 100 copies/ml) amplifying the terminal protein (TP) region of HBV was established and HBV DNA was detected in 12.5% of the samples. In 70% of these samples, the HBV DNA concentration was below 500 copies/ml as measured by real-time PCR in the S gene. Logistic regression analysis revealed that the chance of detecting HBV DNA was increased by a positive HCV serostatus (odds ratio 5.0, 95%-CI 1.6-15.7), whereas HIV coinfection (odds ratio 2.0, 95%-CI 0.7-5.8), anti-HBs (odds ratio 0.9, 95%-CI 0.3-2.6), and HCV RNA status (odds ratio 0.4, 95%-CI 0.1-1.7) had no statistically significant influence. In contrast, the chance of detecting HCV RNA in the subgroup of anti-HCV-positive sera was increased by HIV coinfection (odds ratio 4.5, 95%-CI 1.2-17.4). Sequencing of the TP PCR products revealed neither a specific phylogenetic origin of the circulating HBV DNA nor clustering of uncommon mutations in the TP region. CONCLUSIONS: The prevalence of HBV DNA in serum of anti-HBc-positive/HBsAg-negative subjects correlates with HCV rather than HIV serostatus.     

HPA polymorphism in sub-Saharan African populations: Beninese, Cameroonians, Congolese, and Pygmies

The frequency of human platelet antigen-1 (HPA-1) to HPA-11w (excluding HPA-8w) and HPA-15 systems was studied in four sub-Saharan populations: Beninese, Congolese (Democratic Republic of Congo Kinshasa), Cameroonians, and Aka pygmies (Central African Republic). No report of HPA prevalence has previously been published concerning these populations which are characterized by the highest HPA-2b gene frequencies of any reported to date (Aka 0.393, Benin 0.292, Cameroon 0.237, and Congo 0.224) and at lesser degree HPA-5b (Aka 0.405, Congo 0.268, Cameroon 0.254, and Benin 0.182). This study is of great importance (i) particularly in the context of the diversity caused by the population migrations, we may observe today in our hospitals (ii) to confirm that the Pygmy population with distinctive frequencies (absence of the HPA-1b, HPA-2b, and HPA-5b highest frequencies) is an isolated population.     

Herbal remedies and their adverse effects in Tem tribe traditional medicine in Togo

In Africa, up to 80% of the population relies on herbal concoctions for their primarily health care. In Togo, western Africa, Tem tribe is a population with old knowledge of medicinal plants, however, still very little is known about their medical practices. The present study was conducted to access for the apprehension of adverse effects of traditional remedies by Tem traditional healers (TH). Enquiry was performed by interviews with healers from August to October 2007 in Tchaoudjo prefecture (Togo). The study allowed us to interview 54 TH including 41(75.93%) males and 13(24.07%) females, who cited 102 recipes assumed to have adverse effects. The recipes were used alone to cure several diseases including haemorrhoids (22.55%), female sexual disorders and infertility (21.57%), gastrointestinal disorders (18.63%), and malaria (6.86%). A total of 34 plants belonging to 21 families were cited to be components of the recipes. Euphorbiaceae and Mimosaceae families were the most represented, however, Nauclea latifolia, Khaya senegalensis, Pseudocedrela kotschyi and Xeroderris stuhlmannii were the main components of recipes linked to adverse effects. A total of 20 adverse effects were linked to the administration of theses drugs, and among them; diarrhoea, abdominal pains, polyuria, general weakness and vomiting were the most frequently encountered. These findings were in accordance with several reports of the literature concerning medicinal plants, although they were based on empirical observations. Laboratory screenings are needed to access for the effectiveness as well as the possible toxic effects of the recipes.     

Module based antibody engineering: a novel synthetic REDantibody

We describe the facile generation of a stable recombinant antibody with intrinsic red fluorescent properties for qualitative and potentially quantitative immunofluorescence analysis. The REDantibody based on the X-ray crystallographic structures of the anti-sialyl-Tn antibody B72.3 and 3D model of the monomeric red fluorescent protein was designed to retain optimal spatial geometry between the C- and N-termini of the V(H) and V(L) chains respectively to mimic the domains interface pairing in antibody Fab fragments and to incorporate the red fluorescent protein as a bridging scaffold. The model was further validated by assembling a REDantibody based on CA19.9 the anti-sialylated Lewis (Le)(a) blood group antigen and 4D5-8 the anti-p185(HER2) antibodies. The chimeric heavy and light chains containing red fluorescent protein as a bridge were correctly processed and secreted into Escherichia coli periplasm for assembly and disulphide bond formation, further analysis revealed the molecules to be exclusively monomers. Purified anti-glycan proteins were used for an immunofluorescent analysis of Trypanosoma cruzi epimastigotes, and the anti-p185(HER2) used to determine the binding properties. The REDantibody platform facilitates rapid generation of scFv chimeras that could be used for screening antibodies against cell surface markers. Furthermore, such modular assembly should permit the interchange of binding sites and of fluorophores to create robust panels of coloured antibodies.