318 research outputs found
Philosophical approach of homeopathy
A philosophical examination provides insight into the identity of homeopathy and a better understanding of its necessary link to biomedicine. The first point is to identify the simultaneous birth of homeopathy and biomedicine at the turn of the years 1790 to 1810. Two conceptions appear which differ, as well as regarding the definition of health and disease as the concept of chronicity. Both conceptions do not fit either in the same frames of philosophical references. Platon: objectification, mechanism, realistic objects, molecular design side of biomedicine. Aristote: phenomenology, vitalism, realism of the relations, energy and information on the side of homeopathy. The issue of evaluation of homeopathy is also discussed. But the text does not restrict to underline the differences between biomedicine and homeopathy; it also suggests joining them in a complex scientific vision, which would open the medical universe to a new, pluralistic and democratic dimension
Mexican Medicinal Plants as an Alternative for the Development of New Compounds Against Protozoan Parasites
The protozoan parasites Plasmodium, Leishmania, Trypanosoma, Entamoeba histolytica, Giardia lamblia, and Trichomonas vaginalis, cause high morbidity and mortality in developed and developing countries. P. falciparum is responsible for malaria, one of the most severe infectious diseases in Africa. Hundreds of million people are affected by Trypanosoma and Leishmania that cause African and South American trypanosomiasis, and leishmaniasis. E. histolytica and G. lamblia contribute to the enormous burden of diarrheal diseases worldwide; trichomoniasis is the most common nonviral sexually transmitted disease in the world. Because of the important side effects of current treatments and the decrease in drug susceptibility, there is a renewed interest for the search of therapeutic alternatives against these pathogens. Natural products obtained from medicinal plants and their derivatives have been recognized for many years as a source of therapeutic agents. There are numerous reports about medicinal plants that are used by indigenous communities to treat gastrointestinal complaints. Importantly, phytochemical studies have allowed the identification of several secondary metabolites with anti-parasite activity. Our review revealed that Mexican medicinal plants have a great potential for the identification of new molecules with activity against protozoan parasites of medical importance worldwide and their potential use as new therapeutic compounds
DNA Repair in Pathogenic Eukaryotic Cells: Insights from Comparative Genomics of Parasitic Protozoan
Impact of the chemical composition of poly-substituted hydroxyapatite particles on the in vitro pro-inflammatory response of macrophages
International audienceTo improve the biological properties of calcium phosphate (CaP) bone substitute, new chemical compositions are under development. In vivo such materials are subject to degradation that could lead to particles release and inflammatory reactions detrimental to the bone healing process. This study aimed at investigating the interactions between a murine macrophage cell line (RAW 264.7) and substituted hydroxyapatite particles presenting promising biological properties. Micron size particles of stoichiometric and substituted hydroxyapatites (CO 3 substitution for PO 4 and OH; SiO 4 substitution for PO 4; CO 3 and SiO 4 co-substitution) were obtained by aqueous precipitation followed by spray drying. Cells, incubated with four doses of particles ranging from 15 to 120 µg/mL, revealed no significant LDH release or ROS production, indicating no apparent cytotoxicity and no oxidative stress. TNF-α production was independent of the chemistry of the particles; however the particles elicited a significant dose-dependent pro-inflammatory response. As micron size particles of these hydroxyapatites could be at the origin of inflammation, attention must be paid to the degradation 2 behavior of substituted hydroxyapatite bone substitute in order to limit, in vivo, the generation of particulate debris
Accurate characterization of pure silicon-substituted hydroxyapatite powders synthesized by a new precipitation route
International audienceThis paper presents a new aqueous precipitation method to prepare silicon-substituted hydroxyapatites Ca10(PO4)6-y(SiO4)y(OH)2-y(VOH)2-y (SiHAs) and details the characterization of powders with varying Si content up to y = 1.25 mol molSiHA−1. X-ray diffraction, transmission electron microscopy, solid-state nuclear magnetic resonance and Fourier transform infrared spectroscopy were used to accurately characterize samples calcined at 400°C for 2 h and 1000°C for 15 h. This method allows the synthesis of monophasic SiHAs with controlled stoichiometry. The theoretical maximum limit of incorporation of Si into the hexagonal apatitic structure is y < 1.5. This limit depends on the OH content in the channel, which is a function of the Si content, temperature and atmosphere of calcination. These results, particularly those from infrared spectroscopy, raise serious reservations about the phase purity of previously prepared and biologically evaluated SiHA powders, pellets and scaffolds in the literature
Unravelling the relevance of the polyadenylation factor EhCFIm25 in entamoeba histolytica through proteomic analysis
We recently reported that silencing of the polyadenylation factor EhCFIm25 in Entamoeba histolytica, the protozoan which causes human amoebiasis, affects trophozoite proliferation, death, and virulence, suggesting that EhCFIm25 may have potential as a new biochemical target. Here, we performed a shotgun proteomic analysis to identify modulated proteins that could explain this phenotype. Data are available via ProteomeXchange with identifier PXD027784. Our results revealed changes in the abundance of 75 proteins. Interestingly, STRING analysis, functional GO‐term annotations, KEGG analyses, and literature review showed that modulated proteins are mainly related to glycolysis and carbon metabolism, cytoskeleton dynamics, and parasite virulence, as well as gene expression and protein modifications. Further studies are needed to confirm the hypotheses emerging from this proteomic analysis, to thereby acquire a comprehensive view of the molecular mechanisms involved
Detection of the Endosomal Sorting Complex Required for Transport in Entamoeba histolytica and Characterization of the EhVps4 Protein
Eukaryotic endocytosis involves multivesicular bodies formation, which is driven by endosomal sorting complexes required for transport (ESCRT). Here, we showed the presence and expression of homologous ESCRT genes in Entamoeba histolytica. We cloned and expressed the Ehvps4 gene, an ESCRT member, to obtain the recombinant EhVps4 and generate specific antibodies, which immunodetected EhVps4 in cytoplasm of trophozoites. Bioinformatics and biochemical studies evidenced that rEhVps4 is an ATPase, whose activity depends on the conserved E211 residue. Next, we generated trophozoites overexpressing EhVps4 and mutant EhVps4-E211Q FLAG-tagged proteins. The EhVps4-FLAG was located in cytosol and at plasma membrane, whereas the EhVps4-E211Q-FLAG was detected as abundant cytoplasmic dots in trophozoites. Erythrophagocytosis, cytopathic activity, and hepatic damage in hamsters were not improved in trophozoites overexpressing EhVps4-FLAG. In contrast, EhVps4-E211Q-FLAG protein overexpression impaired these properties. The localization of EhVps4-FLAG around ingested erythrocytes, together with our previous results, strengthens the role for EhVps4 in E. histolytica phagocytosis and virulence
Caractérisation de tissu osseux et de biomatériaux pour la régénération osseuse sur gros volume.
L’objectif de cette étude est de développer
un processus expérimental de régénération de tissus osseux de grand volume. Une première
étape vise à produire du matériau osseux à partir de lambeau de périoste vascularisé et
à le caractériser grâce a des essais d’indentation. Ensuite, nous développons un process
impliquant un biomatériau poreux et biodégradable utilisé comme réceptacle de cellules
mésenchymateuses. Dans les deux cas, le nouveau matériau obtenu est étudié grâce à des
tests mécaniques et biologiques
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