8 results on '"Siarkos I"'
Search Results
2. Delineating cost-effective wellhead protection zones in a rural area in Greece.
- Author
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Siarkos, I., Latinopoulos, D., and Katirtzidou, M.
- Subjects
WELLHEAD protection ,COST effectiveness ,RURAL geography ,WATER supply ,GEOGRAPHIC information systems - Abstract
The aim of this study is the protection of groundwater resources from nitrate pollution by regulating land use and by establishing guidelines for agricultural activities within specific wellhead protection areas. Wellhead protection zones are specifically designed in four wells in the municipality of Nea Moudania, an area of intensive agricultural activities in northern Greece. Recent water samples from these wells indicate high levels of nitrates concentrations. Wellhead protection areas are delineated through a geographic information systems ( GIS) analysis in order to determine the boundaries of protection zones, as well as to identify the land use patterns and the specific crop types around the contaminated wells. Different land use management techniques for groundwater protection zoning are also examined with respect to their implementation cost. The purpose of this analysis is to identify the least expensive management strategy for wellhead protection. The results show that land use changes are always more expensive than implementing agro-environmental measures. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
3. Effect of silibinin on endothelial dysfunction and ADMA levels in obese diabetic mice
- Author
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Siarkos Ilias, Urso Vincenzo, Mangiameli Andrea, Sorrenti Valeria, Salomone Salvatore, Li Volti Giovanni, Galvano Fabio, and Salamone Federico
- Subjects
diabetes ,silibinin ,db/db ,endothelial dysfunction ,ADMA ,vascular reactivity ,Diseases of the circulatory (Cardiovascular) system ,RC666-701 - Abstract
Abstract Background Cardiovascular diseases (CVD) in diabetic patients have endothelial dysfunction as a key pathogenetic event. Asymmetric dimethylarginine (ADMA), an endogenous inhibitor of nitric oxide synthase (NOS), plays a pivotal role in endothelial dysfunction. Different natural polyphenols have been shown to preserve endothelial function and prevent CVD. In this study, we assessed the effect of silibinin, a widely used flavonolignan from milk thistle, on ADMA levels and endothelial dysfunction in db/db mice. Methods Eight-week-old db/db mice were administrated a 20 mg/Kg i.p. daily dose of silibinin (n = 6) or vehicle (n = 6) for four weeks. Heterozygous lean db/m mice served as control. Plasma, aorta and liver ADMA levels were determined by ELISA. Vascular reactivity to phenilephrine (PE), acetylcholine (ACh), sodium nitroprusside (SNP) and ADMA was assessed in isolated aortic segments, in wire myograph. Results Plasma and aorta ADMA levels were higher in db/db than in control lean mice. Silibinin administration markedly decreased plasma ADMA; consistently, aorta ADMA was reduced in silibinin-treated animals. Plasma and aorta ADMA levels exhibited a positive correlation, whereas liver ADMA was inversely correlated with both plasma and aorta ADMA concentrations. Endothelium-(NO)-dependent vasodilatation to ACh was impaired in db/db mice and was restored in the silibinin group, in accordance with the observed reduction of plasma and vascular levels of ADMA. Endothelium-independent vasodilatation to SNP was not modified by silibinin administration; contractile tone induced in isolated aorta from db/db mice by challenging with exogenous ADMA was not affected by the treatment. Conclusions Silibinin markedly improves endothelial dysfunction in db/db mice by reducing circulating and vascular ADMA levels. Clinical studies are warranted to assess the efficacy of silibinin for cardiovascular protection.
- Published
- 2011
- Full Text
- View/download PDF
4. Implementation and evaluation of different techniques to modify DRASTIC method for groundwater vulnerability assessment: a case study from Bouficha aquifer, Tunisia.
- Author
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Siarkos I, Arfaoui M, Tzoraki O, Zammouri M, and Hamzaoui-Azaza F
- Subjects
- Tunisia, Environmental Monitoring methods, Water Pollution analysis, Models, Theoretical, Groundwater
- Abstract
Groundwater vulnerability assessment has nowadays evolved into an essential tool towards proper groundwater protection and management, while the DRASTIC method is included among the most widely applied vulnerability assessment methods. However, the high uncertainty of the DRASTIC method mainly associated with the subjectivity in assigning parameters ratings and weights has driven many researchers to apply various methods for improving its efficiency. In this context, in the present study, different techniques were implemented with the aim of modifying the DRASTIC framework and thus enhancing its performance for groundwater vulnerability assessment in the Bouficha aquifer, Tunisia. In a first stage, the land use type (L) was incorporated as an additional parameter in the typical DRASTIC framework, thus taking into consideration the impact of anthropogenic activities on groundwater vulnerability. Subsequently, the rating and weighting systems of the developed DRASTIC-L framework were modified through the application of statistical methods (DRASTIC-L-SA) and genetic algorithms (GA) (DRASTIC-L-GA) in an attempt to investigate and compare both linear and nonlinear modifications. To evaluate the various vulnerability frameworks, correlation between vulnerability values and nitrate concentrations, expressed as Spearman's rank correlation coefficient (ρ) and Correlation Index (CI), was examined. The results revealed that the DRASTIC-L-GA framework developed by applying a fully GA-based optimization procedure provided the highest values in terms of the performance metrics used, making it the most suitable for the study area. In addition, the aquifer under study was found to be less vulnerable to pollution when employing the typical DRASTIC framework instead of the modified ones, leading to the conclusion that the former substantially underestimates pollution potential in the study area., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)
- Published
- 2023
- Full Text
- View/download PDF
5. A methodological framework to assess the environmental and economic effects of injection barriers against seawater intrusion.
- Author
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Siarkos I, Latinopoulos D, Mallios Z, and Latinopoulos P
- Subjects
- Cost-Benefit Analysis, Groundwater, Environmental Monitoring, Seawater
- Abstract
Seawater intrusion is responsible for the progressive deterioration of groundwater quality in numerous coastal aquifers worldwide. As a consequence, seawater intrusion may constitute a serious threat to local groundwater resources, as well as to the regional economy of coastal areas. To alleviate these negative effects, a number of well-designed protective measures could be implemented. The implementation of these measures is usually associated with significant benefits for the environment and the local economy. In this perspective, the present study investigates the particular case of constructing injection barriers for controlling seawater intrusion by developing a methodological framework that combines numerical modeling with spatial and cost-benefit analyses. To this task, we introduce a novel approach, which considers the socio-economic aspects of seawater intrusion in the modeling procedure, and at the same time focuses on the spatial and temporal relationships between water salinity and farmers' income. To test the proposed methodology two alternative artificial recharge scenarios - with different volumes of water used for injection - are assessed. According to the results of this analysis, both scenarios are likely to have a positive impact on groundwater quality, as well as, a net economic benefit to local society., (Copyright © 2017 Elsevier Ltd. All rights reserved.)
- Published
- 2017
- Full Text
- View/download PDF
6. Reversible inhibition of vasoconstriction by thiazolidinediones related to PI3K/Akt inhibition in vascular smooth muscle cells.
- Author
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Sinagra T, Tamburella A, Urso V, Siarkos I, Drago F, Bucolo C, and Salomone S
- Subjects
- Anilides pharmacology, Animals, Chromans pharmacology, Dose-Response Relationship, Drug, Enzyme Inhibitors pharmacology, Femoral Artery, Male, Muscle, Smooth, Vascular physiology, Myocytes, Smooth Muscle physiology, Nitroarginine pharmacology, PPAR gamma antagonists & inhibitors, Phosphatidylinositol 3-Kinases genetics, Phosphatidylinositol 3-Kinases metabolism, Pioglitazone, Proto-Oncogene Proteins c-akt genetics, Proto-Oncogene Proteins c-akt metabolism, Rats, Rats, Sprague-Dawley, Rosiglitazone, Troglitazone, Muscle, Smooth, Vascular cytology, Myocytes, Smooth Muscle drug effects, Phosphoinositide-3 Kinase Inhibitors, Proto-Oncogene Proteins c-akt antagonists & inhibitors, Thiazolidinediones pharmacology, Vasoconstriction drug effects
- Abstract
Thiazolidinediones (also referred to as glitazones), agonists for Peroxisome Proliferator-Activated Receptor gamma (PPARγ), are used for treating type 2 diabetes mellitus, where they decrease insulin resistance and cardiovascular risk. Compounds bearing the thiazolidinedione structure have also been shown to inhibit phosphoinositide 3-kinase (PI3K). Here we tried to elucidate the poorly defined role of PI3K/Akt in the physiology of vascular smooth muscle cell contraction and tested the hypothesis that thiazolidinediones, by affecting the PI3K/Akt pathway, may influence vascular physiology. Isolated rat femoral arteries segments were mounted in a wire myograph and challenged with 100mM KCl or phenylephrine (PE), in the absence or presence of troglitazone, rosiglitazone, pioglitazone, LY294002 (PI3K inhibitor) and 10-DEBC (Akt inhibitor). All these compounds dose-dependently inhibited vasoconstriction to KCl or PE; their effect was reversible (after 60-120 min washout) and not affected by GW9662 (a PPARγ antagonist) or by N(G)-nitro-L-arginine (LNNA, an inhibitor of NO biosynthesis). Analysis of phospho-Akt (ser 473) in lysates from rat arteries (by immunoblot) revealed that thiazolidinediones, LY294002 and 10-DEBC, at the same concentration and kinetics inhibiting vasoconstriction, produced a similar decrease of Akt phosphorylation. PI3K/Akt pathway therefore appears to be an important, fast acting, modulator of contraction of vascular smooth muscle. Thiazolidinediones decrease vasoconstriction of isolated vessels possibly by inhibiting PI3K/Akt pathway. Such an effect of glitazones, if occurring in vivo, may impact cardiovascular syndromes related to vasospasm in diabetic patients., (Copyright © 2012 Elsevier Inc. All rights reserved.)
- Published
- 2013
- Full Text
- View/download PDF
7. Effect of silibinin on endothelial dysfunction and ADMA levels in obese diabetic mice.
- Author
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Li Volti G, Salomone S, Sorrenti V, Mangiameli A, Urso V, Siarkos I, Galvano F, and Salamone F
- Subjects
- Acetylcholine pharmacology, Animals, Antioxidants pharmacology, Aorta drug effects, Aorta metabolism, Aorta physiopathology, Arginine metabolism, Disease Models, Animal, Endothelium, Vascular metabolism, Insulin Resistance physiology, Liver metabolism, Male, Mice, Mice, Obese, Nitroprusside pharmacology, Phenylephrine pharmacology, Silybin, Vasoconstrictor Agents pharmacology, Vasodilator Agents pharmacology, Arginine analogs & derivatives, Diabetes Mellitus metabolism, Diabetes Mellitus physiopathology, Endothelium, Vascular drug effects, Endothelium, Vascular physiopathology, Obesity metabolism, Obesity physiopathology, Silymarin pharmacology
- Abstract
Background: Cardiovascular diseases (CVD) in diabetic patients have endothelial dysfunction as a key pathogenetic event. Asymmetric dimethylarginine (ADMA), an endogenous inhibitor of nitric oxide synthase (NOS), plays a pivotal role in endothelial dysfunction. Different natural polyphenols have been shown to preserve endothelial function and prevent CVD. In this study, we assessed the effect of silibinin, a widely used flavonolignan from milk thistle, on ADMA levels and endothelial dysfunction in db/db mice., Methods: Eight-week-old db/db mice were administrated a 20 mg/Kg i.p. daily dose of silibinin (n = 6) or vehicle (n = 6) for four weeks. Heterozygous lean db/m mice served as control. Plasma, aorta and liver ADMA levels were determined by ELISA. Vascular reactivity to phenilephrine (PE), acetylcholine (ACh), sodium nitroprusside (SNP) and ADMA was assessed in isolated aortic segments, in wire myograph., Results: Plasma and aorta ADMA levels were higher in db/db than in control lean mice. Silibinin administration markedly decreased plasma ADMA; consistently, aorta ADMA was reduced in silibinin-treated animals. Plasma and aorta ADMA levels exhibited a positive correlation, whereas liver ADMA was inversely correlated with both plasma and aorta ADMA concentrations. Endothelium-(NO)-dependent vasodilatation to ACh was impaired in db/db mice and was restored in the silibinin group, in accordance with the observed reduction of plasma and vascular levels of ADMA. Endothelium-independent vasodilatation to SNP was not modified by silibinin administration; contractile tone induced in isolated aorta from db/db mice by challenging with exogenous ADMA was not affected by the treatment., Conclusions: Silibinin markedly improves endothelial dysfunction in db/db mice by reducing circulating and vascular ADMA levels. Clinical studies are warranted to assess the efficacy of silibinin for cardiovascular protection.
- Published
- 2011
- Full Text
- View/download PDF
8. Endothelium-dependent vasomotor effects of telmisartan in isolated rat femoral arteries.
- Author
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Siarkos I, Urso V, Sinagra T, Drago F, and Salomone S
- Subjects
- Animals, Endothelium, Vascular physiology, Femoral Artery physiology, Male, Organ Culture Techniques, Rats, Rats, Sprague-Dawley, Telmisartan, Vasoconstriction physiology, Vasodilation physiology, Benzimidazoles pharmacology, Benzoates pharmacology, Endothelium, Vascular drug effects, Femoral Artery drug effects, Vasoconstriction drug effects, Vasodilation drug effects
- Abstract
AT(1) receptor antagonists (ARBs) are drugs widely used for preventing and/or treating major cardiovascular diseases. Some of these drugs also show AT(1) receptor-independent effects that may have patho-physiological significance, such as Peroxisome Proliferator-Activated Receptors gamma (PPARγ) stimulation. Here we investigated the effect of telmisartan (that also stimulates PPARγ) on vasomotor responses of femoral arteries isolated from rat, in comparison to losartan. Femoral artery segments were mounted in a wire myograph and challenged with cumulative concentrations of phenylephrine (PE) and acetylcholine (ACh) after 30-min incubation in the absence or presence of 30 μM telmisartan or 30 μM losartan. Vasomotor responses were not significantly changed by losartan, whereas telmisartan reduced vasoconstriction to PE and increased vasodilatation to ACh. Incubation with 0.1 mM N(G)-nitro-l-arginine abolished relaxation to ACh in untreated controls as well as in losartan-treated preparations, but did not in telmisartan-treated preparations (were 20% relaxation subsisted); this residual relaxing effect was abolished by indomethacin and by endothelium removal. Incubation with 30 μM GW9662 (PPARγ antagonist), 10 μM PD123319 (AT(2) antagonist) or 30 μM A779 (angiotensin(1-7)/Mas antagonist) did not change the effect of telmisartan on vasomotor responses in preparations with intact endothelium. We conclude that telmisartan modifies constriction and dilatation of isolated arteries in an endothelium-dependent manner, involving both nitric oxide and prostanoid production. The present effect of telmisartan, however, does not seem to involve PPARγ, AT(2) or angiotensin(1-7)/Mas., (Copyright © 2010 Elsevier Ltd. All rights reserved.)
- Published
- 2011
- Full Text
- View/download PDF
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