Discovery of Type 3 von Willebrand Disease in a Cohort of Patients with Suspected Hemophilia A in Côte d'Ivoire.

BACKGROUND: Type 3 von Willebrand disease (VWD) is the most severe form of VWD, characterized by a near-total absence of von Willebrand factor (vWF), leading to a massive deficiency in plasmatic factor VIII (FVIII). VWD may be confused with hemophilia A, sometimes leading to misdiagnosis. The purpose of this work was to finalize the biological diagnosis of patients with FVIII activity deficiency in Abidjan in order to guide the best type of management. METHODS: We conducted a cross-sectional descriptive study from June 2018 to April 2019. Forty-nine patients, all of whom had lower FVIII levels or had been referred for a bleeding disorder, were monitored in the clinical hematology service. The pro-coagulant activity of coagulation factors was performed in Abidjan. The assays for von Willebrand antigen and activity were performed at Nîmes University Hospital in France. RESULTS: The mean age of patients was 13.8 years (1 - 65) and 86% were Ivorian. FVIII deficiency was discovered during a biological checkup, circumcision or post-traumatic bleeding, in 33%, 31% and 29% respectively. The FVIII deficiency of patients was classified as severe (89.8%), moderate (8.2%) and mild (2%). Only one patient had a quantitative deficiency of von Willebrand factor (vWF: Ag <3%) with undetectable von Willebrand factor activity (vWF: Ac) and an FVIII level <1%. CONCLUSIONS: Not all of the congenital deficiency of FVIII are represented by hemophilia A. It was crucial to assess the Willebrand factor of these patients followed in Côte d'Ivoire for whom hemophilia A had been suspected.

Measured (and estimated) glomerular filtration rate: reference values in West Africa.

Background: Establishment of normal reference values for glomerular filtration rate (GFR) is mandatory in nephrology. However, no data are available for measured GFR (mGFR) in Africa. Methods: GFR was measured in 237 healthy adult subjects (103 women and 134 men, mean age 34 ± 10 years) by iohexol plasma clearance. Results: The mean mGFR was 103 ± 17 mL/min/1.73 m2 and the median value was 103 mL/min/1.73 m2 (2.5th and 97.5th percentiles are 76 and 137 mL/min/1.73 m2, respectively). No significant difference in mGFR results was observed in patients < 40 years of age, whereas a significant decline in mGFR was observed after 40 years of age. There was no significant difference between mGFR in men and women. Conclusions: Normal GFR values and descriptions of percentiles are now available for West Africa. As in Caucasians, no significant difference was observed between men and women. Moreover, the same age-associated decline in mGFR is also observed after 40 years of age, as in Caucasians.

[Inadequacy of the African-American ethnic factor to estimate glomerular filtration rate in an African general population: Results from Côte d'Ivoire]. / Inadéquation du facteur ethnique pour l'estimation du débit de filtration glomérulaire en population générale noire-africaine : résultats en Côte d'Ivoire.

Glomerular filtration rate (GFR) estimation is fundamental in clinical nephrology. It is usually estimated from equations based on serum creatinine. An ethnic factor is currently recommended for the black population for the two most used equations, i.e. the Chronic Kidney Disease-Epidemiology Collaboration (CKD-EPI) and Modification of Diet in Renal Disease (MDRD) study equations. However, these factors were determined from African-American subjects. Therefore, their use in the African subject (non-American) remained questionable. To date, no data are available in West Africa for the adequacy of these ethnic coefficients, as compared with a measurement of GFR by a reference method. One hundred and twenty subjects of the general population, with no nephrologic history, were included in the study (60 women and 60 men). GFR was determined by a reference method, i.e. the plasma clearance of iohexol. The performance (bias, standard deviation, accuracy within 30%) of both CKD-EPI and MDRD study equations were assessed with and without the ethnic factors. GFR measurements (mGFR) according iohexol reference method were 100±19mL/min/1.73m2. The MDRD study equation without any ethnic factor underestimates mGFR by -9±16mL/min/1.73m2, whereas the MDRD study equation with the ethnic factor overestimates mGFR by +10±18mL/min/1.73m2. Regarding the CKD-EPI equation, bias and accuracy within 30% are significantly better without than with the ethnic factor. Indeed, bias is 16±2mL/min/1.73m2 and 18±17mL/min/1.73m2 and accuracy is 93% and 76%, without and with the ethnic factor, respectively (P<0.0001). We show for the first time in African population that the performance of CKD-EPI and MDRD study equations is significantly better, in a general population, without the "African-American" ethnic factor. The "African-American" ethnic factor should not be applied in West Africa.

Surface metabolites of the brown alga Taonia atomaria have the ability to regulate epibiosis.

This study aimed to improve understanding of the strategies developed by the Mediterranean seaweed Taonia atomaria to chemically control bacterial epibiosis. An experimental protocol was optimized to specifically extract algal surface-associated metabolites by a technique involving dipping in organic solvents whilst the integrity of algal cell membranes was assessed by fluorescent microscopy. This methodology was validated using mass spectrometry-based profiles of algal extracts and analysis of their principal components, which led to the selection of methanol as the extraction solvent with a maximum exposure time of 15 s. Six compounds (A-F) were identified in the resulting surface extracts. Two of these surface-associated compounds (B and C) showed selective anti-adhesion properties against reference bacterial strains isolated from artificial surfaces while remaining inactive against epibiotic bacteria of T. atomaria. Such specificity was not observed for commercial antifouling biocides and other molecules identified in the surface or whole-cell extracts of T. atomaria.