Publications by authors named "Leondios Leondiadis"

Climate change poses new challenges for environmental protection and food safety. With reported consequences including warmer temperatures, melting of Alpine glaciers, higher sea levels, droughts, extreme rainfall events and increased surface UV radiation, concerns about the impact on food contaminants have been raised. While the effects of climate change on POPs were initially expected to have the biggest impact in the arctic region, given the intensity, frequency and spread of extreme weather events, global influence on environmental pollution and food safety is currently anticipated.

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The blood levels of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) have been thoroughly investigated in Greek children from the Rhea birth cohort study. This investigation aimed to assess exposure levels, explore their possible relationship with children's age and sex, and indicate potential sources of exposure. Exposure patterns and common sources of PCBs and OCPs were analyzed using bivariate and multivariate statistics.

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Concentration levels of 26 polycyclic aromatic hydrocarbons and 20 trace elements were measured in dietary samples, in order to estimate the dietary intake and the potential exposure risk of the Greek population. Dietary samples were collected with the help of 30 volunteers inhabitants of Athens, Greece, according to the duplicate portion study (DPS) method where the determination of the compounds is conducted in the final consumed meal. DPS was selected as an alternative to a total diet study for its feasibility, low cost and realistic image that it provides.

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A new sensitive and selective gas chromatography tandem mass spectrometry (GC-MS/MS) method was developed for the analysis of 26 polycyclic aromatic hydrocarbons (PAHs), including 16 Environmental Protection Agency (EPA) and 15 + 1 European Union (EU) PAHs, in mussel samples from aquaculture farms in Thermaikos and Strymonian Gulf, Central Macedonia Region, in three sampling periods. Concentrations were found at moderate to low values at all sampling sites, without exceeding maximum levels set by EU. Low molecular weight PAHs were predominant in all samples.

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Food consumption has been recognized as the most significant contributor to human exposure to polyfluoroalkyl and perfluoroalkyl substances (PFASs) for the general population. In 2020, EFSA introduced for the first time safety limit of 4.4 ng/kg body weight (bw) for weekly intake for the sum of perfluorooctanoic acid (PFOA), perfluorooctane sulfonic acid (PFOS), perfluorononanoic acid (PFNA) and perfluorohexane sulfonic acid (PFHxS) which are all perfluoralkyl acids (PFAAs) that belong to PFASs group.

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Food and drinking water intake are the major routes of exposure to perfluoroalkyl substances (PFASs) for humans. In this study an initial oral exposure assessment of the non-occupationally exposed general Greek population to PFASs is presented. Levels of PFOA and PFOS determined in the present study in 128 food items from the Greek market and previously published analytical results of 43 water samples and 76 egg samples from Greece were combined with food availability data of the DAFNE-ANEMOS database for the calculation of oral intake of PFASs.

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This study was aimed at assessing the prenatal exposure to perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) in a cohort of pregnant women living in Reus (Tarragona County, Catalonia, Spain). These chemicals were biomonitored in maternal plasma during the first trimester of pregnancy, at delivery, and in cord blood. The dietary exposure of PFOS and PFOA was estimated by using questionnaires of food frequency and water intake, as well as data on food levels previously reported in the same area.

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Sample preparation is of critical importance in dioxin analysis of food and feed samples. It is a complex procedure that includes lipid extraction followed by the application of chromatographic separation techniques, aiming in removing undesirable interferences from the matrix. The separation of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) from polychlorinated biphenyls (PCBs) is achieved by carbon-based materials which should have high fat capacity in order to be suitable for lipid-containing matrices.

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Background: The European Union's 7th Framework Programme (EU's FP7) project HEALS - Health and Environment-wide Associations based on Large Population Surveys - aims a refinement of the methodology to elucidate the human exposome. Human biomonitoring (HBM) provides a valuable tool for understanding the magnitude of human exposure from all pathways and sources. However, availability of specific biomarkers of exposure (BoE) is limited.

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Perfluoroalkylated substances (PFASs) present a potential health risk for consumers. In animals these compounds are known to accumulate in livers. In order to determine potential PFASs contamination in commercially available livers, samples from farmed sheep, horses, cows, pigs and chicken were collected from the Dutch market.

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Fish is among the essential components of Mediterranean diet and has beneficial effects on human health. Farmed fish is an affordable alternative to wild fish and a significant food export product for Greece. Published studies worldwide have reported significant levels of environmental pollutants in fish tissues.

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Dietary intake is a major route of human exposure to perfluoroalkylated substances (PFASs). However, the available information on PFAS levels in food, including chicken eggs, is limited. In the present study, home produced and commercially produced eggs (organic, battery and free range eggs) were collected from the Netherlands (n = 95) and Greece (n = 76).

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In the present study 11 perfluoroalkylated substances (PFASs) were analysed in drinking tap water samples from the Netherlands (n = 37) and from Greece (n = 43) by applying LC-MS/MS and isotope dilution. PFASs concentrations above the limit of quantification, LOQ (0.6 ng/l) were detected in 20.

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Perfluorinated compounds (PFCs) were analyzed in several species of small Mediterranean fish and shellfish, all of which are popular in Greek diet. Analysis was conducted in raw samples and in samples cooked by the two ways preferred in Greek cuisine, i.e.

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Perfluorinated compounds (PFCs) are used in food packaging materials as coatings/additives for oil and moisture resistance. In the current study, foodstuff-packaging materials collected from the Greek market, made of paper, paperboard or aluminum foil were analyzed for the determination of PFCs. For the analysis of the samples, pressurized liquid extraction (PLE), liquid chromatography–tandem mass spectrometry (LC–MS/MS) and isotope dilution method were applied to develop a specific and sensitive method of analysis for the quantification of 12 PFCs: perfluorobutanoic acid (PFBA), perfluoropentanoic acid (PFPeA), perfluorohexanoic acid (PFHxA), perfluoroheptanoic acid (PFHpA), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), perfluoroundecanoic acid (PFUnDA), perfluorododecanoic acid (PFDoA), perfluorobutane sulfonate (PFBS), perfluorohexane sulfonate (PFHxS) and perfluorooctane sulfonate (PFOS) and the qualitative detection of 5 more: perfluorotridecanoic acid (PFTrDA), perfluorotetradecanoic acid (PFTeDA), perflyohexadecanoic acid (PFHxDA), perfluorooctadecanoic acid (PFODA) and perfluorodecane sulfonate (PFDS).

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The dietary exposure of infants to polychlorinated dibenzo dioxins and furans (PCDD/Fs) and dioxin like polychlorinated biphenyls (dl-PCBs) is an issue of great social impact. We investigated for the first time the dietary intake of these compounds in infants living in Greece. We included in our study two age groups: 0-6 months, when infants are fed exclusively by human milk and/or formula milk, and 6 to 12 months, when solid food is introduced to nutrition.

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Alpha thymosins are a family of immunostimulating peptides first isolated from thymus gland. In the present work, the structure of the ReO(V)³⁺ complex of an alpha 1 thymosin derivative containing the metal-chelating N,N-dimethylglycyl-L-seryl-L-cysteinyl group was studied with NMR, CD, and ESI. The analysis indicated the existence of two interconverting diastereomers depending on the orientation of the side chain of the chelated Ser syn- or anti- to the oxygen of the ReO(V)³⁺ core.

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The production of perfluorinated compounds which finds application in a wide variety of consumer products has led to their accumulation in the environment. This fact, in combination with their chemical properties of amphiphilicity and chemical stability is the cause of their occurrence in human tissues, which according to reports is widespread, not only in occupationally exposed workers, but also in the general population. In this study, we analyzed 182 blood samples from three different groups of adults living in Greece, in order to evaluate blood levels of two environmentally most common perfluorinated compounds, perfluorooctanesulfonate (PFOS) and perfluorooctanoate (PFOA).

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All three members of the oxytocinase subfamily of M1 aminopeptidases, endoplasmic reticulum aminopeptidase 1 (ERAP1), ERAP2, and placental leucine aminopeptidase (PLAP), also known as insulin-regulated aminopeptidase, have been implicated in the generation of MHC class I-presented peptides. ERAP1 and 2 trim peptides in the endoplasmic reticulum for direct presentation, whereas PLAP has been recently implicated in cross-presentation. The best characterized member of the family, ERAP1, has unique enzymatic properties that fit well with its role in Ag processing.

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During the summer of 2007, a series of massive forest fires broke out in several areas across Greece. The main sources of PCDD/Fs and dioxin-like PCBs in Greece are considered to be the uncontrolled combustion of municipal solid waste in open landfills and accidental fires in forest, rural and industrial areas. Combustion may also lead to the formation of PAHs, which are fat soluble substances of considerable toxicity.

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Angiotensin-converting enzyme (ACE) is a key molecule of the renin-angiotensin-aldosterone system which is responsible for the control of blood pressure. For over 30 years it has become the target for fighting off hypertension. Many inhibitors of the enzyme have been synthesized and used widely in medicine despite the lack of ACE structure.

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The interaction of pineal hormone melatonin, the histological dye thioflavin T, and the olive tree polyphenol oleuropein, with the 28 amino acid residue N-terminal fragment of the beta-amyloid peptide (beta-AP) of Alzheimer's disease, [beta-AP(1-28)], was detected in solution through the observation of transferred NOEs (trNOEs) in 1D and 2D NOE spectroscopy (NOESY) experiments. The trNOE method is applied for the first time in the detection of interactions of soluble beta-AP(1-28) with small molecules and may provide a means of screening for the identification of possible inhibitors of the formation of neurotoxic beta-AP assemblies.

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We report here a case study of dioxin contamination after a fire in the public landfill of Tagarades, which is situated southeast of Thessaloniki, Greece. The aim of this study was to determine the levels of PCDD/Fs and PCBs in food samples of meat, eggs, dairy products and vegetables, collected near the affected area, and to compare them with the usual levels found in Greek food. Soil samples were also gathered from various sites at a distance up to 5km from the landfill.

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Background: Endoplasmic reticulum aminopeptidase 1 (ERAP1) trims N-terminally extended antigenic peptide precursors down to mature antigenic peptides for presentation by major histocompatibility complex (MHC) class I molecules. ERAP1 has unique properties for an aminopeptidase being able to trim peptides in vitro based on their length and the nature of their C-termini.

Methodology/principal Findings: In an effort to better understand the molecular mechanism that ERAP1 uses to trim peptides, we systematically analyzed the enzyme's substrate preferences using collections of peptide substrates.

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