Construction, synthèse physco-chimiques et utilisation de sondes dans létude de la topographie de biomembranes

No Abstract Available j. Rech. Sci. Univ. Lomé (Togo) 2002, 6(1) : 103-11

Optimisation des paramètres d'extraction à froid de l'huile d'Azadirachta indica A. Juss et effets sur quelques caractéristiques chimiques de l'huile extraite

Optimization of the parameters of cold extraction of the oil of Azadirachta indica A. Juss and effects on some chemical parameters of the extracted oil. Azadirachta indicaA.Juss (neem) is a tropical tree, popular for its multiple possible uses. The oil extracted from neem kernels is used in cosmetics, as medicines, as insecticides and for energy needs (biofuel). The oldest oil extraction method is cold pressing. However, the optimal parameters of extraction and the quality of extracted oil are poorly known. The purpose of this research was to identify the optimal extracting parameters of neem oil by cold pressing and to characterize the extracted oil. The results showed that at 25 °C, the optimum yield by pressing of whole kernels was obtained with a pressure of 30.4 MPa ± 4.1 and a maximum degree of filling of the pressing cage. We showed that maintaining this pressure for 6 min could lead to an extraction rate of 40.1% ± 1.1. The oil yield increased with the speed of kernel compression. Reducing the particle size had a positive effect on oil yield when the cage load did not exceed half of the cage capacity. The best oil yield of 40.3% ± 0.0 for ground kernels was obtained with a pressure of 33.7 MPa ± 2.9 and a cage filled in the quarter of its capacity. The content levels of water, iron, copper and phosphorus in the oil extracted by pressing were respectively 0.14%; 11.8; 0.1 and 17 ppm. These characteristics indicate, inter alia, that neem oil obtained by cold pressing is of appropriate quality for use in biodiesel production

Clinical, Paraclinical, and Evolutionary Profiles of Kidney Failure in Gold Miners Hospitalized in a Nephrological Service in a Sub-Saharan African Country

Introduction. The purpose of this preliminary study is to describe the clinical, paraclinical, and evolutionary profiles of gold miner patients with kidney failure hospitalized in the nephrology and haemodialysis service in the Yalgado Ouédraogo University Hospital of Ouagadougou (CHU-YO). Patients and Methods. This was a longitudinal and descriptive study with a retrospective collection of data for the period from February 1, 2013, to March 31, 2018. Included were all gold miner patients who stayed and worked at an artisanal gold mining site for at least three months and who were diagnosed with acute or chronic kidney failure during hospitalization in the nephrology service. We collected sociodemographic, clinical, and paraclinical variables at admission and then three months later. Results. We included 50 patients; all were male and the average age was 29.4 ± 7.7 years. All patients were exposed to mercury and/or cyanide for an average of 4.5 ± 2.8 years. The average consultation/referral time for patients at the CHU-YO was 25.4 ± 14.9 days. The average of creatininemia was 2338.0 ± 791.4 μmol/L. Kidney failure was acute in five cases (10%) and chronic in the remaining 45 cases or 90%. Extrarenal purification was indicated in 43 cases (86%). It was not performed in nine of the 43 cases due to lack of financial resources for patients (six cases) or death prior to the onset of haemodialysis (three cases). Thirty-two of the 50 patients in the study (64% of cases) died. Conclusion. Chronic kidney failure in gold miners appears to be common and late-managed. A prospective study of kidney disease and its causes at gold mining sites and surrounding areas will assess the extent of the problem in the country and better clarify the prevention of these diseases in our country

Synthesis and fluorescence properties of novel transmembrane probes and determination of their orientation within vesicles

Two novel transmembrane fluorescent diester probes D and E bearing an anthracenediyl moiety in the middle of the molecule have been synthesized. Their absorption and fluorescence spectra in CHCl3 solution as well as their fluorescence characteristics in dimyristoylphosphatidylcholine (DMPC) large unilamellar vesicles were determined. Although their absorption spectra (first transition, S-0 --> S-1) present a good overlap with the fluorescence spectrum of tryptophan, only probe E could be a good acceptor for the energy-transfer experiments, since a strong overlap exists between the absorption spectrum of tryptophan and the second transition (S-0 --> S-2) of the absorption spectrum of probe D. The Forster critical distance R-0 for energy transfer between tryptophan (donor) and probe E (acceptor) is found to be 23-24 Angstrom. Finally, linear-dichroism studies on shear-deformed DMPC vesicles show the incorporated probe E to lie essentially perpendicular to the bilayer plane. These results establish that probe E could be useful in the study of membrane-bound protein topography by the fluorescence-energy-transfer method