Polyamide from lactams by reactive rotational molding via anionic ring-opening polymerization: Optimization of processing parameters

A reactive rotational molding (RRM) process was developed to obtain a PA6 by activated anionic ring-opening polymerization of epsilon-caprolactam (APA6). Sodium caprolactamate (C10) and caprolactam magnesium bromide (C1) were employed as catalysts, and difunctional hexamethylene-1,6-dicarbamoylcaprolactam (C20) was used as an activator. The kinetics of the anionic polymerization of !-caprolactam into polyamide 6 was monitored through dynamic rheology and differential scanning calorimetry measurements. The effect of the processing parameters, such as the polymerization temperature, different catalyst/activator combinations and concentrations, on the kinetics of polymerization is discussed. A temperature of 150°C was demonstrated to be the most appropriate. It was also found that crystallization may occur during PA6 polymerization and that the combination C1/C20 was well suited as it permitted a suitable induction time. Isoviscosity curves were drawn in order to determine the available processing window for RRM. The properties of the obtained APA6 were compared with those of a conventionally rotomolded PA6. Results pointed at lower cycle times and increased tensile properties at weak deformation

Lantana: Lantana camara (Verbenaceae)

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Améloblastome mandibulaire place de la radiothérapie

L’améloblastome est la tumeur odontogénique la plus fréquente. il  représente 1% des tumeurs mandibulaires et maxillaires et atteint la mandibule dans 80% des cas. Son traitement se base essentiellement sur la chirurgie lorsque cela est possible. La radiothérapie est réservée aux formes inopérables localement évoluées et métastatiques. Les auteurs rapportent le cas d’un patient présentant un améloblastome mandibulaire kystique traité par radiothérapie exclusive.Mots clés: Améloblastome, mandibule, radiothérapi

Erythropoietin-induced hypertension and vascular injury in mice overexpressing human endothelin-1: exercise attenuated hypertension, oxidative stress, inflammation and immune response

OBJECTIVE: Erythropoietin used to correct anaemia in chronic kidney disease (CKD) has been shown to increase blood pressure (BP) in CKD patients and experimental animals. Endothelin (ET)-1 expression is increased in CKD animals and patients, and enhanced by erythropoietin. Erythropoietin-induced BP rise was blunted by ETA receptor blockers. This study was designed to determine whether preexisting endothelin (ET)-1 overexpression is required for erythropoietin to cause adverse vascular effects and whether this could be prevented by exercise training. METHODS: Eight to 10-week old male wild-type mice and mice with endothelial-specific ET-1 overexpression (eET-1) were treated or not with EPO (100 IU/kg, SC, 3 times/week). eET-1 was subjected or not to swimming exercise training (1 h/day, 6 days/week) for 8 weeks. SBP, mesenteric artery endothelial function and remodelling, NADPH oxidase activity, reactive oxygen species (ROS) generation, vascular cell adhesion protein (VCAM)-1, monocyte/macrophage infiltration, T regulatory cells (Tregs) and tissue ET-1 and plasma endothelin were determined. RESULTS: Erythropoietin increased SBP by 24 mmHg (P < 0.05) and decreased by 25% vasodilatory responses to acetylcholine (P < 0.01) in eET-1 mice. Erythropoietin enhanced ET-1 induced increase in resistance artery media/lumen ratio (31%, P < 0.05), aortic NADPH oxidase activity (50%, P < 0.05), ROS generation (93%, P < 0.001), VCAM-1 (80%, P < 0.01) and monocyte/macrophage infiltration (159%, P < 0.001), and raised plasma and aortic ET-1 levels (>/=130%, P < 0.05). EPO had no effect in wild-type mice. Exercise training prevented all of the above (P < 0.05). CONCLUSION: Erythropoietin-induced adverse vascular effects are dependent on preexisting elevated ET-1 expression. Exercise training prevented erythropoietin-induced adverse vascular effects in part by inhibiting ET-1 overexpression-induced oxidative stress, inflammation and immune activation

Changes of Sand Fly Populations and Leishmania infantum Infection Rates in an Irrigated Village Located in Arid Central Tunisia

Citation: Barhoumi, W., Fares, W., Cherni, S., Derbali, M., Dachraoui, K., Chelbi, I., . . . Zhioua, E. (2016). Changes of Sand Fly Populations and Leishmania infantum Infection Rates in an Irrigated Village Located in Arid Central Tunisia. International Journal of Environmental Research and Public Health, 13(3), 10. doi:10.3390/ijerph13030329The current spread of zoonotic visceral leishmaniasis (ZVL) throughout arid areas of Central Tunisia is a major public health concern. The main objective of this study is to investigate whether the development of irrigation in arid bio-geographical areas in Central Tunisia have led to the establishment of a stable cycle involving sand flies of the subgenus Larroussius and Leishmania infantum, and subsequently to the emergence of ZVL. Sand flies were collected from the village of Saddaguia, a highly irrigated zone located within an arid bio-geographical area of Central Tunisia by using modified Centers for Diseases Control (CDC) light traps. Morphological keys were used to identify sand flies. Collected sand flies were pooled with up to 30 specimens per pool according to date and tested by nested Polymerase Chain Reaction (PCR) DNA sequencing from positive pools was used to identify Leishmania spp. A total of 4915 sand flies (2422 females and 2493 males) were collected from Saddaguia in September and in October 2014. Morphological identification confirmed sand flies of the subgenus Larroussius to be predominant. PCR analysis followed by DNA sequencing indicated that 15 pools were infected with L. infantum yielding an overall infection rate of 0.6%. The majority of the infected pools were of sand fly species belonging to subgenus Larroussius. Intense irrigation applied to the arid bio-geographical areas in Central Tunisia is at the origin of the development of an environment capable of sustaining important populations of sand flies of the subgenus Larroussius. This has led to the establishment of stable transmission cycles of L. infantum and subsequently to the emergence of ZVL

n-3 polyunsaturated fatty acids suppress CD4+ T cell proliferation by altering phosphatidylinositol-(4,5)-bisphosphate [PI(4,5)P2] organization

AbstractThe mechanisms by which n-3 polyunsaturated fatty acids (n-3 PUFA), abundant in fish oil, exert their anti-inflammatory effects have not been rigorously defined. We have previously demonstrated that n-3 PUFA decrease the amount of phosphatidylinositol-(4,5)-bisphosphate, [PI(4,5)P2], in CD4+ T cells, leading to suppressed actin remodeling upon activation. Since discrete pools of PI(4,5)P2 exist in the plasma membrane, we determined whether n-3 PUFA modulate spatial organization of PI(4,5)P2 relative to raft and non-raft domains. We used Förster resonance energy transfer (FRET) to demonstrate that lipid raft mesodomains in the plasma membrane of CD4+ T cells enriched in n-3 PUFA display increased co-clustering of Lck(N10) and LAT(ΔCP), markers of lipid rafts. CD4+ T cells enriched in n-3 PUFA also exhibited a depleted plasma membrane non-raft PI(4,5)P2 pool as detected by decreased co-clustering of Src(N15), a non-raft marker, and PH(PLC-δ), a PI(4,5)P2 reporter. Incubation with exogenous PI(4,5)P2 rescued the effects on the non-raft PI(4,5)P2 pool, and reversed the suppression of T cell proliferation in CD4+ T cells enriched with n-3 PUFA. Furthermore, CD4+ T cells isolated from mice fed a 4% docosahexaenoic acid (DHA)-enriched diet exhibited a decrease in the non-raft pool of PI(4,5)P2, and exogenous PI(4,5)P2 reversed the suppression of T cell proliferation. Finally, these effects were not due to changes to post-translational lipidation, since n-3 PUFA did not alter the palmitoylation status of signaling proteins. These data demonstrate that n-3 PUFA suppress T cell proliferation by altering plasma membrane topography and the spatial organization of PI(4,5)P2