Theoretical and Experimental Elucidation of the Adsorption Process of a Bioinspired Peptide on Mineral Surfaces.

Inorganic materials used for biomedical applications such as implants generally induce the adsorption of proteins on their surface. To control this phenomenon, the bioinspired peptidomimetic polymer 1 (PMP1), which aims to reproduce the adhesion of mussel foot proteins, is commonly used to graft specific proteins on various surfaces and to regulate the interfacial mechanism. To date and despite its wide application, the elucidation at the atomic scale of the PMP1 mechanism of adsorption on surfaces is still unknown. The purpose of the present work was thus to unravel this process through experimental and computational investigations of adsorption of PMP1 on gold, TiO2, and SiO2 surfaces. A common mechanism of adsorption is identified for the adsorption of PMP1 which emphasizes the role of electrostatics to approach the peptide onto the surface followed by a full adhesion process where the entropic desolvation step plays a key role. Besides, according to the fact that mussel naturally controls the oxidation states of its proteins, further investigations were performed for two distinct redox states of PMP1, and we conclude that even if both states are able to allow interaction of PMP1 with the surfaces, the oxidation of PMP1 leads to a stronger interaction.

The invasive shrub Prosopis juliflora enhances the malaria parasite transmission capacity of Anopheles mosquitoes: a habitat manipulation experiment.

BACKGROUND: A neglected aspect of alien invasive plant species is their influence on mosquito vector ecology and malaria transmission. Invasive plants that are highly attractive to Anopheles mosquitoes provide them with sugar that is critical to their survival. The effect on Anopheles mosquito populations was examined through a habitat manipulation experiment that removed the flowering branches of highly attractive Prosopis juliflora from selected villages in Mali, West Africa. METHODS: Nine villages in the Bandiagara district of Mali were selected, six with flowering Prosopis juliflora, and three without. CDC-UV light traps were used to monitor their Anopheles spp. vector populations, and recorded their species composition, population size, age structure, and sugar feeding status. After 8 days, all of the flowering branches were removed from three villages and trap catches were analysed again. RESULTS: Villages where flowering branches of the invasive shrub Prosopis juliflora were removed experienced a threefold drop in the older more dangerous Anopheles females. Population density dropped by 69.4% and the species composition shifted from being a mix of three species of the Anopheles gambiae complex to one dominated by Anopheles coluzzii. The proportion of sugar fed females dropped from 73 to 15% and males from 77 to 10%. CONCLUSIONS: This study demonstrates how an invasive plant shrub promotes the malaria parasite transmission capacity of African malaria vector mosquitoes. Proper management of invasive plants could potentially reduce mosquito populations and malaria transmission.

Rapid tests and transfusion safety in Niamey, Niger.

To evaluate the virological safety of blood components provided by the Niamey blood transfusion center after undergoing rapid tests. Samples found negative with rapid tests (n = 222) were screened by the Abbott Prism assay. Positive samples were confirmed by appropriate methods. Of 222 samples, nine (4.1%) were reactive for all markers. After confirmation, seven samples were positive (i.e., 3.2% false-negative results) : five (2.3%) for the surface antigen of hepatitis B (HBsAg) and two (0.9%) for the antibody directed against the hepatitis C virus (HCV-Ab). No false negative results were observed for HIV-Ab (antibody directed against the Human Immunodeficiency Virus). The performance of the rapid tests used in Niamey to screen for transfusion-transmissible infections is not satisfactory, especially for hepatitis B and C. The use of more sensitive tests should be considered to minimize the risk of contaminating patients receiving blood components.

[Utilization of a pedicled labial flap, single or double face, for the management of post-obstetric urethral damage]. / Utilisation du lambeau labial pédiculé retourné simple ou double face pour le traitement des destructions urétrales post-obstétricales. A propos de 56 cas.

Reported here is our experience with a single or double-face new procedure using a pedicled labial flap for urethral reconstruction in patients treated for extensive urethral damage after obstetrical injury. Between January 1992 to July 1997, 56 cases of urethral damage on African female patients, with an average age of 18 years old, were treated by pedicled labial urethroplasty. This procedure was done by using a single or double-face pedicled flap obtained from the major or minor labia. The flap was then introduced as in a tunnel beneath the vaginal epithelium reaching the damaged urethra. A variety of techniques were proposed: patch for sufficient lengthening (27 cases), tubularized flap allowing complete reconstruction of the urethra (18 cases) and the double-face urethroplasty (11 cases). Good quality urine continence was obtained by using the sub urethral Martius'sling procedure. In 11 cases, we combined the treatment with a colposuspension procedure. The average follow-up was 23 months (ranging from 5 to 47 months). The global success was 82% (52 patients treated). Recovery of normal miction and absence of urinary leak was obtained in 36 cases (69%). While 7 moderate failures occurred (13%), 9 cases were considered complete failures (17%). In view of the high success rate, we consider that the one-stage procedure by the use of a single or double face pedicled labial flap is a choice treatment and highly suitable for the management of extensive urethral cervical damage after obstetrical injury.