251 research outputs found

    Correlation of the 83w421 Kortrijk (Sint-Antonius) and 83w44 Kortrijk (Lust) boreholes with acritarchs (late Aeronian-early Telychian, Silurian, Belgium)

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    25 samples from the 83W421 Kortrijk (Sint-Antonius) and 83W44 Kortrijk (Lust) boreholes are investigated. Acritarchs provide a more reliable and precise correlation of these two boreholes than graptolites and chitinozoans because of large barren and/or not indicative intervals. Based on this correlation, two subzones of the Dactylmofusa estillis Biozone are proposed around the Aeronian-Telychian boundary (Llandovery, Silurian). The two subzones are also found in sections from the Midlands platform and Welsh Basin and thus provides a tool to correlate shallower and deeper facies, at least on a regional scale

    Acritarchs from the Abbaye de Villers and Tribotte Formations in their type section of the Thyle river valley (Middle Ordovician, Brabant Massif, Belgium) and their stratigraphic implications

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    Reinvestigation of the Thyle river section, in the southern part of the Brabant Massif, has led to a better understanding of acritarch distribution in the Middle Ordovician Abbaye de Villers and Tribotte formations, and their stratigraphical significance in the type localities of both formations. The middle and upper parts of the Abbaye de Villers Formation and the lower part of the Tribotte Formation yielded an acritarch assemblage corresponding to the Frankea hamata-Striatotheca rarirrugulata Acritarch Zone of the English Lake District, demonstrating a late Arenig (late Fennian, early Darriwilian) age. Two species, Adorfia firma and Arbusculidium filamentosum, not recorded in the overlying Rigenée Formation, probably have their last appearances below the Arenig-Llanvirn boundary. Acritarch (late Arenig, late Fennian) and chitinozoan datings (middle Arenig, Whitlandian pro parte) of the middle part of the Abbaye de Villers Formation suggest correlation with the older part of the Frankea hamata-Striatotheca rarirrugulata Acritarch Zone. The uppermost part of the Tribotte Formation shows palynological similarities with the overlying Rigenée Formation. The exact position of the Arenig-Llanvirn boundary in the Thyle river section is not yet known and does not necessarily coincide with the Tribotte-Rigenée lithostratigraphical boundary

    Stealth nanocarriers based sterosomes using PEG post-insertion process

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    Sterosomes (STEs), a new and promising non-phospholipidic liposome platform based on palmitic acid (PA) and cholesterol (Chol) mixtures, need to have polyethylene glycol (PEG) chains grafted to their surface in order to obtain long-circulating nanocarriers in the blood stream. A post-insertion method was chosen to achieve this modification. The post-insertion process of PEG-modified distearoylphosphoethanolamine (DSPE-PEG) was monitored using the zeta potential value of STEs. Various conditions including PEG chain length and the DSPE-PEG/PA-Chol ratio, were explored. Zeta potential of STEs changed from about -40mV for non-modified STEs to values close to 0 mV by the end of the process, i.e. for PEG-modified STEs. The kinetics of DSPE-PEG insertion and the stability of the resulting PEG-modified STEs were not considerably influenced, within the investigated range, by changes in PEG chain lengths and in DSPE-PEG/PA-Chol proportion. The post-insertion of PEG chains reduced in vitro complement activation as well as in vitro macrophage uptake compared to the non-modified STEs. Moreover, longer blood circulation time in mice was established for PEG-modified STEs intravenously injected compared to non-modified STEs. These results establish that post-insertion process of PEG chains to STEs is a promising strategy for developing long-term circulating drug delivery nanocarriers

    An overview of anti-diabetic plants used in Gabon: Pharmacology and Toxicology

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    © 2017 Elsevier B.V. All rights reserved.Ethnopharmacological relevance: The management of diabetes mellitus management in African communities, especially in Gabon, is not well established as more than 60% of population rely on traditional treatments as primary healthcare. The aim of this review was to collect and present the scientific evidence for the use of medicinal plants that are in currect by Gabonese traditional healers to manage diabetes or hyperglycaemia based here on the pharmacological and toxicological profiles of plants with anti-diabetic activity. There are presented in order to promote their therapeutic value, ensure a safer use by population and provide some bases for further study on high potential plants reviewed. Materials and methods: Ethnobotanical studies were sourced using databases such as Online Wiley library, Pubmed, Google Scholar, PROTA, books and unpublished data including Ph.D. and Master thesis, African and Asian journals. Keywords including ‘Diabetes’ ‘Gabon’ ‘Toxicity’ ‘Constituents’ ‘hyperglycaemia’ were used. Results: A total of 69 plants currently used in Gabon with potential anti-diabetic activity have been identified in the literature, all of which have been used in in vivo or in vitro studies. Most of the plants have been studied in human or animal models for their ability to reduce blood glucose, stimulate insulin secretion or inhibit carbohydrates enzymes. Active substances have been identified in 12 out of 69 plants outlined in this review, these include Allium cepa and Tabernanthe iboga. Only eight plants have their active substances tested for anti-diabetic activity and are suitables for further investigation. Toxicological data is scarce and is dose-related to the functional parameters of major organs such as kidney and liver. Conclusion: An in-depth understanding on the pharmacology and toxicology of Gabonese anti-diabetic plants is lacking yet there is a great scope for new treatments. With further research, the use of Gabonese anti-diabetic plants is important to ensure the safety of the diabetic patients in Gabon.Peer reviewedFinal Accepted Versio

    La chimiothérapie inhalée – partie 1 : concept et challenges technologiques actuels

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    Despite severe adverse effects, chemotherapy is still widely used in the treatment of lung tumors, including primary lung tumors and metastases. In order to reduce the risk of harm and to intensify treatment responses, several strategies have been described recently. These include the use of nanomedicine-based chemotherapies and pulmonary drug delivery. However, to treat lung tumors, inhalation cannot be effective and safe without an adaptation of current inhalation techniques, i.e. inhalation devices and drug formulations. This can be very challenging. This review presents recent preclinical developments that could address the limitations observed with aerosolized chemotherapy. The solutions involve the use of dry powder inhalers and advanced drug formulations, such as controlled and sustained release formulations and nanomedicine-based formulations

    La chimiothérapie inhalée – partie 2 : clinique et applications potentielles

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    Lung tumours have a high incidence and cause many deaths worldwide. Despite progresses in treatment with targeted therapies and immunotherapies, the global 5-year survival rate remains low. In this context, inhaled chemotherapy could provide a means to intensify current therapeutic modalities. This review is based on clinical studies of inhaled chemotherapy against lung tumours. The advantages of this approach in terms of pharmacokinetic ratio and therapeutic index are presented as well as the limitations including contraindications and pulmonary side effects. Moreover, the challenges linked to technical aspects around administration are identified (inhalation device and facilities to limit aerosol propagation and exposure of healthcare professionals). The current developments proposed to overcome these challenges are described briefly. Also discussed are the potential applications for the distribution of the inhaled anticancer drug into tumour-bearing respiratory tracts and finally the potential indications for current therapeutic modalities

    Safe lipid nanocapsule-based gel technology to target lymph nodes and combat mediastinal metastases from an orthotopic non-small-cell lung cancer model in SCID-CB17 mice

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    The purpose of this study is the assessment of gel technology based on a lauroyl derivative of gemcitabine encapsulated in lipid nanocapsules delivered subcutaneously or intravenously after dilution to target lymph nodes, induce less systemic toxicity and combat mediastinal metastases from an orthotopic model of human, squamous, non-small-cell lung cancer Ma44-3 cells implanted in severe combined immunodeficiency mice. The gel technology mainly targeted lymph nodes as revealed by the biodistribution study. Moreover, the gel technology induced no significant myelosuppression (platelet count) in comparison with the control saline group, unlike the conventional intravenous gemcitabine hydrochloride treated group (P < 0.05). Besides, the gel technology, delivered subcutaneously twice a week, was able to combat locally mediastinal metastases from the orthotopic lung tumor and to significantly delay death (P < 0.05) as was the diluted gel technology delivered intravenously three times a week
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