1,721,262 research outputs found
Phytochemical composition and biological activity of extracts from Lebanese medicinal plants
No full textThe Mediterranean area especially the eastern part including Lebanon, is rich in term of plant biodiversity, including high valuable medicinal plants that are largely used by people as herbal medicine, these plants represent an important source of plant-derived bioactive compounds, besides, there is a need to characterize these compounds, evaluate their bioactivity and clarify scientifically the use of these plant as traditional and alternative medicine, lack of these information may limit their use, by contrast, studying the compositions and bioactivity of these plants may improve their use, discovery of new natural bioactive compounds and finally formulate new plant-based nutraceutical and therapeutically agents. In this context, the aim of my PhD thesis, and as a part of our ongoing program in the medicinal plants filed, was the characterization of a pool of phytochemical compounds with a special focus on polyphenols isolated from different medicinal plants from the Lebanese flora, using analytical tools (as described later in the chapters) including high-performance liquid chromatography (HPLC) coupled with different detectors such as UV-visible and electrospray ioniziation (ESI) Mass spectrometry (MS), following by the study of their biological activities using different in vitro cellular well-established model for several chronic diseases. The plants that I choose for my study have a significant value in the traditional medicine in Lebanon, where they are employed as a food but also in folk medicine to treat/prevent many illnesses. I employed different cellular models of oxidative stress and related chronic diseases (NAFLD, inflammation and cancer)
Advances in the pathophysiology, diagnosis and management of chronic diarrhoea from bile acid malabsorption: a systematic review
No full text: Bile acid malabsorption (BAM) is an important disorder of digestive pathophysiology as it generates chronic diarrhoea. This condition originates from intricate pathways involving bile acid synthesis and metabolism in the liver and gut, the composition of gut microbiota, enterohepatic circulation and key receptors as farnesoid X receptor (FXR), fibroblast growth factor receptor 4 (FGFR4), and the G-protein bile acid receptor-1 (GPBAR-1). Although symptoms can resemble those related to disorders of gut brain interaction, accurate diagnosis of BAM may greatly benefit the patient. The empiric diagnosis of BAM is primarily based on the clinical response to bile acid sequestrants. Specific tests including the 48-hour fecal bile acid test, serum levels of 7α-hydroxy-4-cholesten-3-one (C4) and fibroblast growth factor 19 (FGF19), and the 75Selenium HomotauroCholic Acid Test (SeHCAT) are not widely available. Nevertheless, lack of diagnostic standardization of BAM may account for poor recognition and delayed management. Beyond bile acid sequestrants, therapeutic approaches include the use of FXR agonists, FGF19 analogues, glucagon-like peptide-1 (GLP-1) receptor agonists, and microbiota modulation. These novel agents can best make their foray into the therapeutic armamentarium if BAM does not remain a diagnosis of exclusion. Ignoring BAM as a specific condition may continue to contribute to increased healthcare costs and reduced quality of life. Here, we aim to provide a comprehensive review of the pathophysiology, diagnosis, and management of BAM
The interaction of bile acids and gut inflammation influences the pathogenesis of inflammatory bowel disease
No full textBile acids (BA) are amphipathic molecules originating from cholesterol in the liver and from microbiota-driven biotransformation in the colon. In the gut, BA play a key role in fat digestion and absorption and act as potent signaling molecules on the nuclear farnesoid X receptor (FXR) and membrane-associated G protein-coupled BA receptor-1 (GPBAR-1). BA are, therefore, involved in the maintenance of gut barrier integrity, gene expression, metabolic homeostasis, and microbiota profile and function. Disturbed BA homeostasis can activate pro-inflammatory pathways in the gut, while inflammatory bowel diseases (IBD) can induce gut dysbiosis and qualitative and/or quantitative changes of the BA pool. These factors contribute to impaired repair capacity of the mucosal barrier, due to chronic inflammation. A better understanding of BA-dependent mechanisms paves the way to innovative therapeutic tools by administering hydrophilic BA and FXR agonists and manipulating gut microbiota with probiotics and prebiotics. We discuss the translational value of pathophysiological and therapeutic evidence linking BA homeostasis to gut inflammation in IBD
Converging Pathways between Metabolic Dysfunction–Associated Steatotic Liver Disease (MASLD) and Diabetes in Children
Full text linkIn the past thirty years, childhood obesity rates have risen significantly worldwide, affecting over 340 million children in affluent nations. This surge is intricately tied to metabolic disorders, notably insulin resistance, type 2 diabetes mellitus (T2DM), and the continually evolving spectrum of metabolic-associated (dysfunction) steatotic liver disease (MASLD). This review underscores the alarming escalation of childhood obesity and delves comprehensively into the evolving and dynamic changes of nomenclature surrounding diverse conditions of hepatic steatosis, from the initial recognition of non-alcoholic fatty liver disease (NAFLD) to the progressive evolution into MASLD. Moreover, it emphasizes the crucial role of pediatric endocrinologists in thoroughly and accurately investigating MASLD onset in children with T2DM, where each condition influences and exacerbates the progression of the other. This review critically highlights the inadequacies of current screening strategies and diagnosis, stressing the need for a paradigm shift. A proposed solution involves the integration of hepatic magnetic resonance imaging assessment into the diagnostic arsenal for children showing insufficient glycemic control and weight loss post-T2DM diagnosis, thereby complementing conventional liver enzyme testing. This holistic approach aims to significantly enhance diagnostic precision, fostering improved outcomes in this vulnerable high-risk pediatric population
A simulation study on the focal plane detector of the LAUE project
Full text linkAcknowledgements We acknowledge the ASI Italian Space Agency for its support to the LAUE project under contract I/068/09/0 .The LAUE project, supported by the Italian Space Agency (ASI), is devoted to the development of a long focal length (even 20 m or longer) Laue lens for gamma ray astronomy between 80 and 600 keV. These lenses take advantage of Bragg diffraction to focus radiation onto a small spot drastically improving the signal to noise ratio as well as reducing the required size of the detector significantly. In this paper we present a Monte-Carlo simulation study with MEGALIB to optimize, for space applications, the detector size to achieve high detection efficiency, and to optimize the position resolution of the detector to reconstruct the Point Spread Function of the lens considered for the LAUE project. Then we will show simulations, using the SILVACO semiconductor simulation toolkit, on the optimized detector to estimate its capacitance per channel and depletion voltage. In all of the simulations, two materials were compared; a low density material (Silicon) and a high density material (Germanium)
Extent and features of liver steatosis in vitro pave the way to endothelial dysfunction without physical cell-to-cell contact
No full textBackground and aims
Several chronic multifactorial diseases originate from energy unbalance between food intake and body energy expenditure, including non-alcoholic fatty liver disease (NAFLD), diabetes, and cardiovascular disorders. Vascular endothelium plays a central role in body homeostasis, and NAFLD is often associated with endothelial dysfunction (ED), the first step in atherosclerosis. Both sugars and fatty acids (FAs) are fuel sources for energy production, but their excess leads to liver steatosis which may trigger ED through a network of mechanisms which need to be clarified. Here, we investigated the crosstalk pathways between in vitro cultured steatotic hepatocytes (FaO) and endothelial cells (HECV) being mediated by soluble factors.
Methods and results
We employed the conditioned medium approach to test how different extent and features of hepatic steatosis distinctively affect endothelium leading to ED. The steatogenic media collected from steatotic hepatocytes were characterized by high triglyceride content and led to lipid accumulation and fat-dependent dysfunction in HECV cells. We found a parallelism between (i) extent of hepatocyte steatosis and level of lipid accumulation in HECV cells; (ii) type of hepatocyte steatosis (with macro- or microvesicular LDs) and extent of oxidative stress, lipid peroxidation, nitric oxide release and expression of ED markers in HECV cells.
Conclusions
The present findings seem to suggest that, in addition to triglycerides, other soluble mediators should be released by steatotic hepatocytes and may influence lipid accumulation and function of HECV cells. Further studies need to depict the exact profile of soluble factors involved in steatotic hepatocyte-endothelium crosstalk
Long-Term Shoreline Change Analysis in Tyre South Lebanon
No full textThis study investigates shoreline variation along the southern coast of Lebanon in Tyre, an ecologically sensitive area, over a period spanning from 1938 to 2021. Using a combination of cadastral maps, GNSS-based field surveys, and high-resolution satellite imagery (CORONA, KVR-1000, IKONOS, QUICKBIRD, GeoEye-1), a comprehensive temporal analysis was performed. Shoreline changes were evaluated using GIS tools, particularly the Digital Shoreline Analysis System (DSAS), which calculated Net Shoreline Movement (NSM) and End Point Rate (EPR). The findings show that the coastal area remained stable between 1938 and 1964(∼0.69 km2), followed by significant erosion between 1964 and 1994, with a net loss of 0.2 km2(23%). This erosion coincides with the Lebanese Civil War period and related illegal coastal interventions. From 2018 to 2021, an increase in area was observed, probably due to reduced tourism during the COVID-19 pandemic. DSAS results confirmed these trends, with NSM values reaching up to 118 meters and an average EPR of 1.42 m/ year. The results highlight the impact of human activities on shoreline dynamics and emphasize the need for informed coastal zone management to mitigate future risks
Antisteatotic and antioxidant activities of Thymbra spicata L. extracts in hepatic and endothelial cells as in vitro models of non-alcoholic fatty liver disease
No full textEthnopharmacological relevance: Thymbra spicata, a member of the Lamiaceae family, is native to eastern Mediterranean area. Leaves of this plant are rich in phenolic compounds and are a popular remedy of traditional medicine in Lebanon to prevent and/or counteract hyperlipidemia and hyperglycemia. Aim of the study: To evaluate the antisteatotic and antioxidant activities of extracts from leaves of Thymbra spicata L. using in vitro models of non-alcoholic fatty liver disease (NAFLD), a leading cause of liver-related morbidity and mortality worldwide, for whom no effective treatments are still available. Materials and methods: Two different extracts from Thymbra spicata L. aerial parts were prepared using water (TW) or ethanol (TE) as solvent. Their chemical composition was characterized by gas and liquid chromatography coupled with mass spectrometry. Both extracts were tested on cultured hepatic and endothelial cells treated to mimic in vitro a multisistemic pathology such as NAFLD. We assayed the effects on lipid accumulation, free radical production, lipid peroxidation, cell migration. Results: Both the total phenolic and the total flavonoid contents were higher in the ethanolic extract. Rosmarinic acid was the most abundant polyphenol in TW, while TE was richer in carvacrol. Our findings demonstrated that both extracts ameliorated lipid accumulation, oxidative stress and inflammation in the NAFLD cellular models. However, the aqueous extract was more effective to reduce hepatic steatosis, and the ethanolic extract had higheranti-oxidant potential and wound healing activity. Conclusions: T. spicata extracts could be promising bioactive products to develop natural therapeutic agents or dietary supplements to treat NAFLD and obesity-related metabolic disease. Our findings suggest that while the ethanolic extract might be used in preventing endothelium dysfunction, the aqueous extract would act better as lipid-lowering agent
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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