169 results on '"Papaioannou, N."'
Search Results
2. Harmonized quality assurance/quality control provisions to assess completeness and robustness of MS1 data preprocessing for LC-HRMS-based suspect screening and non-targeted analysis
- Author
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Lennon, S., Chaker, J., Price, E.J., Hollender, J., Huber, Carolin Elisabeth, Schulze, T., Ahrens, L., Béen, F., Creusot, N., Debrauwer, L., Dervilly, G., Gabriel, C., Guérin, T., Habchi, B., Jamin, E.L., Klánová, J., Kosjek, T., Le Bizec, B., Meijer, J., Mol, H., Nijssen, R., Oberacher, H., Papaioannou, N., Parinet, J., Sarigiannis, D., Stravs, M.A., Tkalec, Ž., Schymanski, E.L., Lamoree, M., Antignac, J.-P., David, A., Lennon, S., Chaker, J., Price, E.J., Hollender, J., Huber, Carolin Elisabeth, Schulze, T., Ahrens, L., Béen, F., Creusot, N., Debrauwer, L., Dervilly, G., Gabriel, C., Guérin, T., Habchi, B., Jamin, E.L., Klánová, J., Kosjek, T., Le Bizec, B., Meijer, J., Mol, H., Nijssen, R., Oberacher, H., Papaioannou, N., Parinet, J., Sarigiannis, D., Stravs, M.A., Tkalec, Ž., Schymanski, E.L., Lamoree, M., Antignac, J.-P., and David, A.
- Abstract
Non-targeted and suspect screening analysis using liquid chromatography coupled to high-resolution mass spectrometry (LC-HRMS) holds great promise to comprehensively characterize complex chemical mixtures. Data preprocessing is a crucial part of the process, however, some limitations are observed: (i) peak-picking and feature extraction might be incomplete, especially for low abundant compounds, and (ii) limited reproducibility has been observed between laboratories and software for detected features and their relative quantification. We first conducted a critical review of existing solutions that could improve the reproducibility of preprocessing for LC-HRMS. Solutions include providing repositories and reporting guidelines, open and modular processing workflows, public benchmark datasets, tools to optimize the data preprocessing and to filter out false positive detections. We then propose harmonized quality assurance/quality control guidelines that would allow to assess the sensitivity of feature detection, reproducibility, integration accuracy, precision, accuracy, and consistency of data preprocessing for human biomonitoring, food and environmental communities.
- Published
- 2024
3. THEREDA - Thermodynamic Reference Database
- Author
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Moog, H. C., Scharge, T., (0000-0002-5613-2833) Seher, H., (0000-0002-6885-2619) Bok, F., (0000-0001-5570-4177) Brendler, V., Richter, A., (0000-0002-7751-6334) Wissmeier, L., (0000-0002-1348-0811) Henneberg, M., (0000-0002-2639-0903) Altmaier, M., (0000-0002-0787-200X) Gaona, X., Cevirim-Papaioannou, N., (0000-0001-5522-2848) Freyer, D., Pannach, M., (0000-0002-5884-229X) Sohr, J., (0000-0003-2786-6907) Voigt, W., Moog, H. C., Scharge, T., (0000-0002-5613-2833) Seher, H., (0000-0002-6885-2619) Bok, F., (0000-0001-5570-4177) Brendler, V., Richter, A., (0000-0002-7751-6334) Wissmeier, L., (0000-0002-1348-0811) Henneberg, M., (0000-0002-2639-0903) Altmaier, M., (0000-0002-0787-200X) Gaona, X., Cevirim-Papaioannou, N., (0000-0001-5522-2848) Freyer, D., Pannach, M., (0000-0002-5884-229X) Sohr, J., and (0000-0003-2786-6907) Voigt, W.
- Abstract
Part of the process to ensure the safety of radioactive waste disposal is the predictive modeling of the solubility of all relevant toxic components in a complex aqueous solution. To ensure the reliability of thermodynamic equilibrium modeling as well as to facilitate the comparison of such calculations done by different institutions it is necessary to create a mutually accepted thermodynamic reference database. To meet this demand several institutions in Germany joined efforts and created THEREDA (Moog et al., 2015). THEREDA is a suite of programs at the base of which resides a relational databank. Special emphasis is put on thermodynamic data along with suitable Pitzer coefficients which allow for the calculation of solubilities in high-saline solutions. Registered users may either download single thermodynamic data or ready-to-use parameter files for the geochemical speciation codes PHREEQC, Geochemist’s Workbench, CHEMAPP, or TOUGHREACT. Data can also be downloaded in a generic JSON-format to allow for the import into other codes. The database can be accessed via the world wide web: www.thereda.de. Prior to release, the released part of the database is subjected to many tests. Results are compared to results from earlier releases and among the different codes. This is to ensure that by additions of new and modification of existing data no adverse side effects on calculations are caused. Furthermore, our website offers an increasing number of examples for applications, including graphical representation, which can be filtered by components of the calculated system. References Moog, H. C., Bok, F., Marquardt, C. M., and Brendler, V.: Disposal of Nuclear Waste in Host Rock formations featuring high-saline solutions - Implementation of a Thermodynamic Reference Database (THEREDA). Appl. Geochem., 55, 72-84, DOI: 10.1016/j.apgeochem.2014.12.016, 2015.
- Published
- 2023
4. Effect of ISA and chloride on the uptake of niobium(V) by hardened cement paste and C-S-H phases: quantitative description and mechanistic understanding
- Author
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Jo, Y., Çevirim-Papaioannou, N., Franke, K., Fuss, M., Pedersen, M., Lothenbach, B., Blochouse, B., Altmaier, M., Gaona, X., Jo, Y., Çevirim-Papaioannou, N., Franke, K., Fuss, M., Pedersen, M., Lothenbach, B., Blochouse, B., Altmaier, M., and Gaona, X.
- Abstract
The uptake of niobium by hardened cement paste (HCP) a calcium silicate hydrate (C-S-H) phases was investigated with ⁹³Nb and ⁹⁵Nb (t₁/₂=35.0 days). Structural materials used in nuclear reactors as well as cements contain the naturally occurring isotope ⁹³Nb, while radioactive ⁹⁴Nb with t₁/₂=2×10⁴ years is relevant in the context of nuclear waste disposal. Strong uptake of Nb was observed for both materials, confirming that C-S-H are the main sink of Nb in cement. Isotopic exchange with ⁹³Nb in cement can play a role in the uptake of ⁹⁴Nb under repository conditions. The formation of complexes with isosaccharinic acid (ISA) decreases the Nb uptake, although sorption remains strong up to [ISA]tot=0.1 M. Chloride has a negligible effect on the uptake of Nb up to [NaCl] = 2 M. This work provides a sound basis for the quantitative description and mechanistic understanding of ⁹⁴Nb retention in L/ILW repositories.
- Published
- 2023
5. Data publication: Effect of ISA and chloride on the uptake of niobium(V) by hardened cement paste and C-S-H phases: quantitative description and mechanistic understanding
- Author
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Jo, Y., Çevirim-Papaioannou, N., Franke, K., Fuss, M., Pedersen, M., Lothenbach, B., Blochouse, B., Altmaier, M., Gaona, X., Jo, Y., Çevirim-Papaioannou, N., Franke, K., Fuss, M., Pedersen, M., Lothenbach, B., Blochouse, B., Altmaier, M., and Gaona, X.
- Abstract
This dataset is a report about gamma spectroscopy measurement of the irradiated cyclotron target generated by GammaVision software (ORTEC/AMETEK, Version 8.00.03).
- Published
- 2023
6. Automated right ventricular strain by speckle tracking echocardiography in patients with systemic scleroderma
- Author
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Tsoukas, A, primary, Koutsogiannaki, E, additional, Giannakopoulou, I, additional, Gioti, O, additional, Iliopoulos, D, additional, Saad, R, additional, Chalkitis, V, additional, Peteinaki, A, additional, Karapedi, E, additional, and Papaioannou, N, additional
- Published
- 2022
- Full Text
- View/download PDF
7. Uptake of niobium by cement systems relevant for nuclear waste disposal: impact of ISA and chloride
- Author
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Cevirim-Papaioannou, N., Jo, Y., Franke, K., Fuss, M., Blochouse, B., Altmaier, M., Gaona, X., Cevirim-Papaioannou, N., Jo, Y., Franke, K., Fuss, M., Blochouse, B., Altmaier, M., and Gaona, X.
- Abstract
The isotope 94 of niobium (t1/2= 2.04·104 a) is produced during the operation of nuclear reactors due to the neutron activation of 93Nb, which is present in some structural components in nuclear reactor vessels. Related waste streams will be disposed of in repositories for low and intermediate level wastes (L/ILW), where cement is widely used for the stabilization of the waste and for construction purposes. The retention of niobium by young cement was investigated in a series of sorption experiments using a combination of active (95Nb + 91mNb) and inactive (93Nb) niobium isotopes. Sorption experiments assessed also the impact of iso-saccharinic acid (ISA, main degradation product of cellulose) and chloride on Nb retention, both expected in specific L/ILW. A pyrochlore-structure Ca-Nb(V) oxide was found to control the solubility of Nb(V) in cement pore water at pH= 13.5, defining [Nb(V)]aq = 2∙10-6 - 7·10–8 M. Sorption experiments revealed a strong uptake of Nb(V) by cement (5 ≤ log Rd ≤ 7, Rd in L·kg–1), in spite of the predominance of anionic hydrolysis species in the cement pore water. Sorption isotherms were found to be linear within 10–14 M ≤ [Nb(V)]aq ≤ 10–9 M. Calcium silicate hydrate (C-S-H) phases are defined as main sink of Nb(V) in cement, with Ca2+ playing a key role in bridging the negatively charged Nb(V) species to C-S-H. ISA significantly decreases the uptake of Nb(V) at [ISA]aq ≥ 10–4 M, reflecting the formation of stable (Ca-)Nb(V)-ISA complexes in the aqueous phase. Sorption is not affected by chloride within the investigated concentration range (10–5 M ≤ [Cl–] ≤ 1.0 M). This work represents the first experimental evidence on the uptake of niobium by young cement in the absence and presence of ISA and Cl–, thus providing key inputs for the assessment of 94Nb retention in the
- Published
- 2022
8. Relating SARS-CoV-2 shedding rate in wastewater to daily positive tests data: A consistent model based approach
- Author
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Petala, M. Kostoglou, M. Karapantsios, Th Dovas, I, C. and Lytras, Th Paraskevis, D. Roilides, E. and Koutsolioutsou-Benaki, A. Panagiotakopoulos, G. Sypsa, V and Metallidis, S. Papa, A. Stylianidis, E. Papadopoulos, A. and Tsiodras, S. Papaioannou, N.
- Abstract
During the COVID-19 pandemic, wastewater-based epidemiology (WBE) has been engaged to complement medical surveillance and in some cases to also act as an early diagnosis indicator of viral spreading in the community. Most efforts worldwide by the scientific community and commercial companies focus on the formulation of protocols for SARS-CoV-2 analysis in wastewater and approaches addressing the quantitative relationship between WBE and medical surveillance are lacking. In the present study, a mathematical model is developed which uses as input the number of daily positive medical tests together with the highly non-linear shedding rate curve of individuals to estimate the evolution of global virus shedding rate in wastewater along calendar days. A comprehensive parametric study by the model using as input actual medical surveillance and WBE data for the city of Thessaloniki (similar to 700,000 inhabitants, North Greece) during the outbreak of November 2020 reveals the conditions under which WBE can be used as an early warning tool for predicting pandemic outbreaks. It is shown that early warning capacity is different along the days of an outbreak and depends strongly on the number of days apart between the day of maximum shedding rate of infected individuals in their disease cycle and the day of their medical testing. The present data indicate for Thessaloniki an average early warning capacity of around 2 days. Moreover, the data imply that there exists a proportion between unreported cases (asymptomatic persons with mild symptoms that do not seek medical advice) and reported cases. The proportion increases with the number of reported cases. The early detection capacity of WBE improves substantially in the presence of an increasing number of unreported cases. For Thessaloniki at the peak of the pandemic in mid-November 2020, the number of unreported cases reached a maximum around 4 times the number of reported cases. (C) 2021 The Authors. Published by Elsevier B.V.
- Published
- 2022
9. Using neural network and random forest algorithmic approaches to predicting particulate emissions from a highly boosted GDI engine
- Author
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Papaioannou, N, Fang, X, Leach, F, Lewis, A, Akehurst, S, and Turner, J
- Abstract
Particulate emissions from gasoline direct injection (GDI) engines continue to be a topic of substantial research interest. Forthcoming regulation both in the USA and the EU will further reduce their emission and drive innovation. Substantial research effort is spent undertaking experiments to understand, characterize, and research particle number (PN) emissions from engines and vehicles. Recent advances in computing power, data storage, and understanding of artificial intelligence algorithms now mean that these are becoming an important tool in engine research. In this work artificial neural network (ANN) and random forest (RF) algorithms for the prediction of PN emissions from a highly boosted (up to 32 bar BMEP) GDI engine are used. Particle size, concentration and the accumulation mode geometric standard deviation (GSD) are all predicted by the two models. The ANN and RF results are compared, and an in depth study on parameter importance is carried out. The Random Forest algorithm is used as an estimator and the various engine parameters are ranked with a permutation feature importance technique using mean squared error as a performance metric. The results show that from 158 input parameters, only between 13 and 31 (depending on which output is of interest) are needed to characterize the concentration, size, and GSD of the particle spectrums to within 95% of the cumulative mean squared error. Overall, both models show good agreement to the experimental data.
- Published
- 2021
10. Neurodevelopmental effects of prenatal co-exposure to heavy metals and phthalates
- Author
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Anesti, O., primary, Sarigiannis, D., additional, Papaioannou, N., additional, Polanska, K., additional, Hanke, W., additional, Gabriel, A., additional, and Karakitsios, S., additional
- Published
- 2021
- Full Text
- View/download PDF
11. THEREDA - Thermodynamic Reference Database
- Author
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Moog, H. C., Scharge, T., (0000-0002-5613-2833) Seher, H., (0000-0002-6885-2619) Bok, F., (0000-0001-5570-4177) Brendler, V., Richter, A., (0000-0002-7751-6334) Wissmeier, L., (0000-0002-2639-0903) Altmaier, M., (0000-0002-0787-200X) Gaona, X., Cevirim-Papaioannou, N., (0000-0001-5522-2848) Freyer, D., Pannach, M., Sohr, J., (0000-0003-2786-6907) Voigt, W., Moog, H. C., Scharge, T., (0000-0002-5613-2833) Seher, H., (0000-0002-6885-2619) Bok, F., (0000-0001-5570-4177) Brendler, V., Richter, A., (0000-0002-7751-6334) Wissmeier, L., (0000-0002-2639-0903) Altmaier, M., (0000-0002-0787-200X) Gaona, X., Cevirim-Papaioannou, N., (0000-0001-5522-2848) Freyer, D., Pannach, M., Sohr, J., and (0000-0003-2786-6907) Voigt, W.
- Abstract
Part of the process to ensure the safety of radioactive waste disposal is the predictive modeling of the solubility of all relevant toxic components in a complex aqueous solution. To ensure the reliability of thermodynamic equilibrium modeling as well as to facilitate the comparison of such calculations done by different institutions it is necessary to create a mutually accepted thermodynamic reference database. To meet this demand several institutions in Germany joined efforts and created THEREDA 15 (Moog et al., 2015). THEREDA is a suite of programs at the base of which resides a relational databank. Special emphasis is put on thermodynamic data along with suitable Pitzer coefficients which allow for the calculation of solubilities in high-saline solutions. Registered users may either download single thermodynamic data or ready-to-use parameter files for the geochemical speciation codes 20 PHREEQC, Geochemist’s Workbench, CHEMAPP, or TOUGHREACT. Data can also be downloaded in a generic JSON-format to allow for the import into other codes. The database can be accessed via the world wide web: www.thereda.de Prior to release, the released part of the database is subjected to many tests. Results are compared to results from earlier releases and among the different codes. This is to ensure that by additions of new and modification of existing data no adverse side 25 effects on calculations are caused. Furthermore, our website offers an increasing number of examples for applications, including graphical representation, which can be filtered by components of the calculated system. References Moog, H. C., Bok, F., Marquardt, C. M., and Brendler, V.: Disposal of Nuclear Waste in Host Rock formations featuring high-saline solutions - Implementation of a Thermodynamic Reference Database (THEREDA). Appl. Geochem., 55, 72-84, doi: 30 10.1016/j.apgeochem.2014.12.016, 2015.
- Published
- 2021
12. Routine podiatry assessment as a potential preventive tool for atrial fibrillation screening in diabetics
- Author
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Petridou, M, primary, Matopoulou, E, additional, Kanellos, I, additional, Daios, S, additional, Patrikios, I, additional, Charalampous, K, additional, Lampropoulos, K, additional, Stefanou, A, additional, Skantzis, P, additional, Arkouli, V, additional, Papaioannou, N, additional, Papaioannou, G, additional, Kaiafa, G, additional, Savopoulos, C, additional, and Papaioannou, S, additional
- Published
- 2021
- Full Text
- View/download PDF
13. Mapping Cheshire Cats’ Leg: A histological approach of cortical bone tissue through modern GIS technology
- Author
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Mallouchou, M. Katikas, L. Stathopoulou, E. Papaioannou, N. Varagka, N. Nakos, B.
- Abstract
The present study concerns the histological examination of the hind limb of a cat (Felis sp.), with an emphasis on Haversian bone. Acknowledging the variety of obstacles to be confronted, during histological studies, it was decided the documentation, description, and comparison of the longitudinal distribution of the main microstructural characteristics. To reveal what remains hidden from the sight of knowledge, the novel Geographical Information Systems (GIS) methodology was followed. In means to provide conclusive and credible results, it was analyzed the full spectrum of the resulted cross sections and not just a statistical acceptable number or a specific region of interest. In addition, having used the right femur and tibia from the same animal, species and age discrepancies were eliminated. More thoroughly, osteon and Haversian canal size and circularity were calculated and spatially analyzed. Absolute and relative osteon population densities (OPDs) and tissue-type distributions were also estimated. The use of GIS software constituted the core of the current research, since its application transformed cross sections into informative maps, where inter-skeletal, inter-cortical, and intra-cortical distributional patterns were directly recognized and accordingly correlated to strain and load regimes. As result, it is provided the histomorphological and histomorphometrical profile of the samples, under the prism of the existing biomechanical regime. Finally, having further deployed the potentials of GIS software, it is verified and promoted the feasibility of histological mapping as an indispensable procedure, aligned with the necessities of modern science, regardless of discipline or background. © 2019, Japanese Association of Anatomists.
- Published
- 2020
14. Cancer pain ... who cares? : International and national patterns of evidence-based global guide-lines recommendations for physicians on the Web (2011 vs. 2018)
- Author
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Mauri, D., Konstantina Kalopita, Tsali, L., Polyzos, N. P., Valachis, A., Filis, P., Zarkavelis, G., Georgopoulos, C., Zafeiri, G., Yerolatsite, M., Papaioannou, N., Kapoulitsa, F., Valsamidis, D., Peponi, E., Vrekoussis, T., Ntellas, P., Tzamachou, E., and Pentheroudakis, G.
- Subjects
cancer pain ,Cancer och onkologi ,medical societies ,global awareness ,Cancer and Oncology ,oncology ,guideline implementation ,web ,anesthesiology - Abstract
Purpose: Although pain is a common event during treatment of cancer, its assessment and management remains suboptimal in everyday clinical practice at global level. Methods: Considering both the important role of Internet in daily life and that clinical guidelines are important for translating evidence in clinical practice, we performed a prospective study to scrutinize the magnitude of updated evidence-based cancer-pain guideline recommendation for physicians on the web. Changes over-time at a global level were scrutinized at two time points: 2011 for baseline and 2018 at first follow-up. Both anesthesiology and oncology societies were analyzed. Results: In 2011 we scrutinized 181,00 WebPages and 370 eligible societies were identified; 364 of these were eligible for analyses both in 2011 and 2018. The magnitude of cancer pain updated and evidence-based guideline recommendations on the web for health care providers was extremely low at global level and at any time point considered 1.1% (4/364) in 2011 and 4.7% (17364) in 2018. Continental and intercontinental patterns, National's highest developmental index, oncology tradition and economic-geographic areas were not found to influence cancer pain web-guideline provision. In 2018, pain & supportive care societies provided the highest rate of updated evidence-based cancer-pain guidelines for clinicians. Only 3/25 medical oncology societies and 1/34 radiation oncology societies, provided own or e-link (to other societies) evidence-based guidelines in their websites. Conclusions: Major medical oncology and radiation oncology societies - at global level - fail to produce updated cancer pain recommendations for their physicians, with most of these providing no or inconsistent or outdated guidelines.
- Published
- 2020
15. Dietary patterns of greek adults and their associations with serum vitamin d levels and heel quantitative ultrasound parameters for bone health
- Author
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Grigoriou, E. Trovas, G. Papaioannou, N. Dontas, I. Makris, K. Apostolou-Karampelis, K. Dedoussis, G.
- Abstract
The aim of this study is to investigate the dietary patterns which indicate the nutritional habits of Greek adults and their effects on serum 25(OH)D levels and quantitative ultrasound (QUS) parameters for bone health. This study is part of OSTEOS, an observational cross-sectional study. In total, 741 adults from rural and urban areas throughout Greece were recruited. A validated food frequency questionnaire (FFQ) was used for assessment of the population’s dietary habits. Serum 25(OH)D was measured by enzyme immunoassay; QUS parameters were assessed with an Achilles device. Principal component analysis (PCA) was carried out for dietary pattern determination, and univariate analysis of variance was used for the assessment of 25(OH)D, broadband ultrasound attenuation (BUA), speed of sound (SOS), and stiffness index (SI) determinants. Six dietary patterns explain 52.2% of the variability of Greek adults’ nutritional habits. The ‘vegetables–fruit’ dietary pattern explains the biggest rate of variability. Determinants of serum 25(OH)D are body mass index (BMI), elderly status, summer sun exposure, organized physical activity, a ‘healthy’ pattern in winter months, and adherence to a ‘sweet’ pattern. Determinants of QUS parameters are age, BMI, sedentary time, organized physical activity participation, and adherence to a ‘healthy’ pattern. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.
- Published
- 2020
16. THEREDA – Thermodynamic Reference Database
- Author
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Moog, H. C., Scharge, T., (0000-0002-6885-2619) Bok, F., (0000-0001-5570-4177) Brendler, V., Richter, A., Morin, D., Thoenen, T., (0000-0002-2639-0903) Altmaier, M., Cevirim-Papaioannou, N., Gaona, X., Marquardt, C., Freyer, D., Pannach, M., Sohr, J., Moog, H. C., Scharge, T., (0000-0002-6885-2619) Bok, F., (0000-0001-5570-4177) Brendler, V., Richter, A., Morin, D., Thoenen, T., (0000-0002-2639-0903) Altmaier, M., Cevirim-Papaioannou, N., Gaona, X., Marquardt, C., Freyer, D., Pannach, M., and Sohr, J.
- Abstract
Part of the process to assess the safety of disposal sites for radioactive or chemical-toxic waste is the predictive modeling of the solubility of hazardous components in a complex aqueous solution. To ensure the reliability of thermodynamic equilibrium modeling as well as to facilitate the comparison of such calculations done by different institutions it is necessary to create a mutually accepted thermodynamic reference database. To meet this demand in Germany several institutions joined efforts and created THEREDA. It contains a relational databank whose structure was designed in a way that promotes internal consistency of thermodynamic data. It serves as back end to a variety of supplementary programs which allow for adding, editing, and extracting subsets of data. Data considered cover the needs of Gibbs Energy Minimizers and Law-of-Mass-Action programs alike. Interaction parameters for an arbitrary number of mixed phases and p,T-functions of thermodynamic data may also be entered. At present, Pitzer- and SIT-parameters for the aqueous phase are considered. To enhance public use THEREDA is accessible via internet.
- Published
- 2020
17. Association of habitual alcohol consumption with carotid atherosclerotic lesions: results from the Corinthia study
- Author
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Theofilis, P, primary, Oikonomou, E, additional, Vogiatzi, G, additional, Lazaros, G, additional, Tsalamandris, S, additional, Mystakidi, V.C, additional, Goliopoulou, A, additional, Chasikidis, C, additional, Miliou, A, additional, Fountoulakis, P, additional, Papaioannou, N, additional, Papakonstantinou, M, additional, and Tousoulis, D, additional
- Published
- 2020
- Full Text
- View/download PDF
18. Increased exposure to air pollutants leads to greater atherosclerotic burden mediated by systemic inflammation
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Theofilis, P, primary, Oikonomou, E, additional, Vogiatzi, G, additional, Lazaros, G, additional, Mystakidi, V.C, additional, Barbaresos, N, additional, Tasios, P, additional, Tsalamandris, S, additional, Fountoulakis, P, additional, Miliou, A, additional, Papaioannou, N, additional, Asimakopoulos, M.N, additional, and Tousoulis, D, additional
- Published
- 2020
- Full Text
- View/download PDF
19. Thermal investigations on a high-speed direct injection diesel engine
- Author
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Papaioannou, N and Davy, M
- Subjects
Internal combustion engines - Abstract
Modern compression ignition engines offer higher thermal efficiency compared to gasoline engines, thus offering superior fuel consumption performance and lower CO2 emissions, a major greenhouse gas. With future legislation pushing the automotive manufacturers for even lower fleet average CO2 emissions the compression ignition engine can assist in achieving these goals, however further research is required to extend their efficiency. Understanding where the chemical energy of the fuel is transferred during the combustion process and from that identifying strategies that can assist in converting part of these energy flow terms into useful piston work can help enhance the engine’s efficiency. This work looked into the study of these energy flows by using a first law analysis approach and by developing the necessary instrumentation and methods that allow for the more accurate measurement of the various energy flows, subsequently increasing the accuracy of the first law analysis. Two thermal studies were carried out on a single cylinder diesel engine. The first study investigated the effect of different high-pressure EGR strategies on engine efficiency and emissions, in an attempt to reduce the negative effects of EGR application on soot emissions under two load/speed conditions. The second study compared the effects of different piston material on engine efficiency under two speed/load conditions. A baseline aluminium design, was compared against an alloy steel piston which, due to its lower thermal conductivity, was shown to provide lower heat transfer losses during combustion thus increasing efficiency. The results of the thermal studies showed that ~40% of fuel energy was transferred to the exhaust. Therefore, being able to accurately measure the exhaust temperature can offer significant insights to engine designers. The exhaust event is highly unsteady and the exhaust temperature is typically measured using a 3 mm sheathed thermocouple which, due to its thermal mass, cannot capture this transient event. Instead, a time-average measurement is only possible. This can result in an under prediction of the exhaust enthalpy since the measured temperature is lower than that of the flow field of interest due to measurement errors. A lumped capacitance model was developed in order to better understand the behaviour of thermocouple sensors under an unsteady flow environment. The sensors are subject to both dynamic errors, due to their thermal inertia, and conduction and radiation errors due to temperature gradients between the sensor and the surrounding environment. Understanding how different size thermocouples react under unsteady flow conditions has the potential to improve the measurement process and increase the accuracy of the measured exhaust temperature. A temperature reconstruction method was developed which can correct both the dynamic and conduction errors that are prevalent during the engine cycle, thus approaching the true exhaust gas temperature. This technique requires the use of thermocouples with different thermal masses, thus resulting in a different response under the same flow conditions. This reconstructed temperature then allowed the estimation of exhaust enthalpy on a mass-average basis improving the accuracy of the first law analysis.
- Published
- 2019
20. Red Wine Polyphenols Modulate Bone Loss in the Ovariectomized Rat Model of Postmenopausal Osteoporosis
- Author
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Passali, C. Patsaki, A. Lelovas, P. Aligiannis, N. and Makropoulou, M. Kourkoulis, S. Papaioannou, N. Mitakou, S. and Skaltsounis, A. L. Dontas, I
- Subjects
endocrine system ,surgical procedures, operative ,hormones, hormone substitutes, and hormone antagonists - Abstract
The aim of this study was to examine the effect of Red Wine Polyphenols (RWPs) extract on bone mineral density (BMD) in the ovariectomized (OVX) rat model. Thirty-five 10-month-old Wistar rats were separated into controls (CTRL), OVX and OVX plus RWPs in their drinking water (dose, 50 mg/kg body weight per day), starting immediately after OVX for 6 months. Βody and uterine weight, BMD of the tibia at baseline, 3 and 6 months post-OVX, and 3-pointing bending of the femur, were examined. Statistical comparison of the total tibia BMD within groups during the study period showed a significant reduction in the OVX and OVX+RWPs groups both from baseline to 3 and 6 months and from 3 to 6 months, whereas in the CTRL group, there was no significant change. For the proximal tibial metaphysis, comparison of BMD percentage changes from baseline to 3 months and 6 months and from 3 to 6 months revealed highly statistical differences between OVX and OVX+RWPs groups (P = 0.000). OVX induced a significant reduction of biomechanical parameters as expected; the 3-point bending test showed that the maximum force before fracture, energy absorption and fracture stress significantly increased in the OVX group treated with RWPs compared with the nontreated OVX rats (P = 0.048, P = 0.002 and P = 0.003, respectively). Dietary intake of RWPs for 6 months significantly prevented trabecular bone loss and improved bone strength in estrogen-deficient ovariectomized rats. Copyright © 2019 C. Passali, A. Patsaki, P. lelovas, N. Aligiannis, M. Makropoulou, s. Kourkoulis, N. Papaioannou, S. mitakou, A.l. Skaltsounis, I. Dontas
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- 2019
21. The effect of intensive abductor strengthening on postoperative muscle efficiency ands functional ability of hip-fractured patients: A randomized controlled trial
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Stasi, S. Papathanasiou, G. Chronopoulos, E. Dontas, I. Baltopoulos, I. Papaioannou, N.
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body regions - Abstract
Background: Hip fractures are common in the elderly and many patients fail to regain prefracture hip abductor strength or functional status. The purpose of this clinical trial was to compare the effects of an intensive abductor muscle exercise program versus a standard physiotherapy intervention in hip-fractured patients. Materials and Methods: Ninety six femoral neck-fractured patients were randomized into equal-sized groups. A 12-week standard physiotherapy program was implemented in the control group(S-PT) whereas an intensive exercise program, emphasizing on abductors' strengthening, was implemented in the research group(I-PT). Abductors' isometric strength of the fractured hip, abductor ratio% in the fractured compared to contralateral hip, and functional level were assessed at the 3 rd (postintervention) and 6 th (followup) months. Results: Postintervention, abductors' isometric strength was 35.7% greater (P < 0.0005) and abductor ratio% was 2.5% higher (P < 0.0005) in I-PT group, compared to S-PT group. With regard to functional assessments, I-PT group was 29.1% faster during Timed Up and Go (TUG) test and achieved a 26.7% higher Lower Extremity Functional Scale Greek version's (LEFS-Greek) total score, compared to S-PT group (P < 0.0005). At followup, abductors' isometric strength was 37.0% greater (P < 0.0005) and abductor ratio% was 7.1% higher (P < 0.0005) in I-PT group, compared to S-PT group. In addition, I-PT group was 45.9% faster during TUG test (P < 0.0005) and achieved an 11.2% higher LEFS-Greek total score, compared to S-PT group (P = 0.013). Conclusions: Compared to the standard physiotherapy intervention, the intensive abductor-strengthening program significantly increased both abductors' isometric strength of the fractured hip and abductor ratio% and resulted in patients' enhanced functional level. © 2019 Indian Journal of Orthopaedics.
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- 2019
22. Correction to: Conducting an observational study during an economic crisis: analysis of the treatment and follow-up phase of Greek patients participating in the ExFOS study (Hormones, (2018), 17, 4, (531-540), 10.1007/s42000-018-0077-6)
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Aloumanis, K. Kapetanos, G. Alexandridis, T. Drossinos, V. Papaioannou, N. for the Greek ExFOS study group
- Abstract
Unfortunately in the original publication, the affiliation of the author N. Papaioannou was incorrectly provided. The correct affiliation for N. Papaioannou should read as follows: 4 Laboratory for the Research of Musculoskeletal System, School of Medicine, National and Kapodistrian University of Athens, Greece. © 2019, Hellenic Endocrine Society.
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- 2019
23. INTRAOPERATIVE BILIARY SELF-EXPANDABLE METALLIC STENT PLACEMENT in UNRESECTABLE HILAR CHOLANGIOCARCIONOMAS: 5
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Karaliotas, C, Sgourakis, G, Goumas, C, Christofidis, T, and Papaioannou, N
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- 2005
24. PANCREATIC CARCINOMA: EFFECTIVE DIAGNOSIS WITH DUAL-PHASE SPIRAL CT, DSA OR ERCP ?: 22
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Thanos, L, Mylona, S, Goumas, K, Papaioannou, N, Ellinas, P, Karaliotas, K, and Batakis, N
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- 2005
25. SURGICAL VERSUS ENDOSCOPIC PROCEDURES for CHRONIC PANCREATITIS: 12
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Karaliotas, C, Sgourakis, G, Christofidis, T, Papaioannou, N, and Gekas, C
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- 2005
26. Serum 25-hydroxyvitamin D status, quantitative ultrasound parameters, and their determinants in Greek population
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Grigoriou, E.V. Trovas, G. Papaioannou, N. Makras, P. Kokkoris, P. Dontas, I. Makris, K. Tournis, S. Dedoussis, G.V.
- Abstract
Summary: Vitamin D deficiency and quantitative ultrasound measurements are associated with bone fragility. We assessed these parameters and their correlates. 87.7% of the population has vitamin D inadequacy and this correlated with lifestyle factors. These results contribute to epidemiological data needed for population guidelines for bone health. Purpose: Vitamin D deficiency and quantitative ultrasound (QUS) parameters are among the most important clinical risk factors of bone fragility. Few data are available for Greek population. The aim of the study was to evaluate the serum 25-hydroxyvitamin D [25(OH)D] level and their determinants, as well as QUS parameters in Greek population. Methods: OSTEOS is an observational cross-sectional study conducted from June 2010 to July 2012. Nine hundred seventy adults were recruited from rural and urban areas throughout Greece and completed the appropriate questionnaire. Serum 25(OH)D measured by enzyme immunoassay, QUS parameters, broadband ultrasound attenuation (BUA), speed of sound (SOS) and stiffness index (SI), was assessed with an Achilles device. Univariate Analysis of Variance was used for the assessment of serum 25(OH)D determinants. Results: Mean serum 25(OH)D of the total population was 20,00 ± 8,00 ng/mL. Females had lower levels than males. The negative determinants of serum 25(OH)D in the total population were the female sex and the winter-spring season of sampling while age proved negative association solely in obese subjects. Positive determinants of vitamin D status were summer sun exposure and organized physical activity as expected. Urban had lower SOS and SI than rural residents. Individuals with 25(OH)D ≥ 20 ng/mL had higher SOS than those with 25(OH)D < 20 ng/mL. BUA, SOS, and SI are positively correlated with organized physical activity and negatively with PTH. Conclusions: This study reports that vitamin D deficiency is highly prevalent among healthy Greek men and women, demonstrates the multifactorial causation of 25(OH)D levels, and points out that further research is required to determine more factors related to vitamin D status and bone health. © 2018, International Osteoporosis Foundation and National Osteoporosis Foundation.
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- 2018
27. MINIMAL RESIDUAL DISEASE FOR MULTIPLE MYELOMA: CAN WE DO BETTER?
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Kostopoulos, I Kastritis, E Tsitsilonis, O Argyriou, A Roussakis, P Papaioannou, N Dimopoulos, M Terpos, E
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Health Sciences ,Επιστήμες Υγείας - Published
- 2017
28. Effect of calcitriol on FGF23 level in healthy adults and its dependence on phosphate level
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Georgiadou, E. Marketou, H. Trovas, G. Dontas, I. Papaioannou, N. Makris, K. Galanos, A. Papavassiliou, A.G.
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polycyclic compounds ,lipids (amino acids, peptides, and proteins) - Abstract
Aim: To evaluate the short-Term effects of calcitriol and sevelamer hydrochloride on fibroblast growth factor-23 (FGF23) in humans and to determine whether the effect is direct or indirect through calcitriol-induced increased absorption of phosphorus from the intestine. Patients and Methods: A total of 15 healthy individuals were tested at three time points and stages, for 24 h and at 1-week intervals. During each stage, blood samples were taken at three time points (0, 8 and 24 h); baseline stage: under no intervention; second stage, while receiving 0.5 μg calcitriol orally twice daily; and at the third stage, while receiving 0.5 μg calcitriol orally twice daily and sevelamer hydrochloride during meals. The changes in FGF23, parathyroid hormone, calcitriol, Ca, and phosphorus were determined. Results: During calcitriol administration, the FGF23 level changed significantly (p=0.008), with the level at 24 h levels being significantly higher than at 8 h (8.8 pg/ml vs. 13.0 pg/ml, p=0.036). There was a statistically significant difference in the percentage change, among the three stages, at time 8 to 24 h and 0 to 24 h for FGF23 (p=0.014 and p=0.015, respectively), with significant differences between baseline vs. calcitriol for 8 to 24 h FGF23 change (-9.23% vs. 26.98%, p=0.003) and a trend between baseline vs. calcitriol (p=0.061) and calcitriol plus sevelamer (p=0.069) for 0 to 24 h FGF23 change.
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- 2017
29. Factors associated with high 24-month persistence with denosumab: results of a real-world, non-interventional study of women with postmenopausal osteoporosis in Germany, Austria, Greece, and Belgium
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Fahrleitner-Pammer, A. Papaioannou, N. Gielen, E. Feudjo Tepie, M. Toffis, C. Frieling, I. Geusens, P. Makras, P. Boschitsch, E. Callens, J. Anastasilakis, A.D. Niedhart, C. Resch, H. Kalouche-Khalil, L. Hadji, P.
- Abstract
Summary: Persistence with osteoporosis therapy is vital for fracture prevention. This non-interventional study of postmenopausal women receiving denosumab in Germany, Austria, Greece, and Belgium found that persistence with denosumab remains consistently high after 24 months in patients at high risk of fracture. Purpose: Continued persistence with osteoporosis therapy is vital for fracture prevention. This non-interventional study of clinical practice evaluated medication-taking behavior of postmenopausal women receiving denosumab in Germany, Austria, Greece, and Belgium and factors influencing persistence. Methods: Subcutaneous denosumab (60 mg every 6 months) was assigned according to prescribing information and local guidelines before and independently of enrollment; outcomes were recorded during routine practice for up to 24 months. Persistence was defined as receiving the subsequent injection within 6 months + 8 weeks of the previous injection and adherence as administration of subsequent injections within 6 months ± 4 weeks of the previous injection. Medication coverage ratio (MCR) was calculated as the proportion of time a patient was covered by denosumab. Associations between pre-specified baseline covariates and 24-month persistence were assessed using multivariable logistic regression. Results: The 24-month analyses included 1479 women (mean age 66.3–72.5 years) from 140 sites; persistence with denosumab was 75.1–86.0%, adherence 62.9–70.1%, and mean MCR 87.4–92.4%. No covariate had a significant effect on persistence across all four countries. For three countries, a recent fall decreased persistence; patients were generally older with chronic medical conditions. In some countries, other covariates (e.g., older age, comorbidity, immobility, and prescribing reasons) decreased persistence. Adverse drug reactions were reported in 2.3–6.9% patients. Conclusions: Twenty-four-month persistence with denosumab is consistently high among postmenopausal women in Europe and may be influenced by patient characteristics. Further studies are needed to identify determinants of low persistence. © 2017, The Author(s).
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- 2017
30. Response to: A role for thiazide diuretic therapy in preventing bone loss, fracture and nephrolithiasis in individuals with thalassemia and hypercalciuria?
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Dede, A.D. Trovas, G. Chronopoulos, E. Triantafyllopoulos, I.K. Dontas, I. Papaioannou, N. Tournis, S.
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- 2017
31. Secondary sarcopenia in spinal cord injured subjects
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Dionyssiotis, Y., primary, Skarantavos, G., additional, Papaioannou, N., additional, Papagelopoulos, P., additional, Papathanasiou, J., additional, and Lyritis, G., additional
- Published
- 2018
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32. Effects of mechanical loading on the expression of pleiotrophin and its receptor protein tyrosine phosphatase beta/zeta in a rat spinal deformity model
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Kaspiris, A. Chronopoulos, E. Grivas, T.B. Vasiliadis, E. Khaldi, L. Lamprou, M. Lelovas, P.P. Papaioannou, N. Dontas, I.A. Papadimitriou, E.
- Abstract
Mechanical loading of the spine is a major causative factor of degenerative changes and causes molecular and structural changes in the intervertebral disc (IVD) and the vertebrae end plate (EP). Pleiotrophin (PTN) is a growth factor with a putative role in bone remodeling through its receptor protein tyrosine phosphatase beta/zeta (RPTPβ/ζ). The present study investigates the effects of strain on PTN and RPTPβ/ζ protein expression in vivo. Tails of eight weeks old Sprague-Dawley rats were subjected to mechanical loading using a mini Ilizarov external apparatus. Rat tails untreated (control) or after 0 degrees of compression and 10°, 30° and 50° of angulation (groups 0, I, II and III respectively) were studied. PTN and RPTPβ/ζ expression were evaluated using immunohistochemistry and Western blot analysis. In the control group, PTN was mostly expressed by the EP hypertrophic chondrocytes. In groups 0 to II, PTN expression was increased in the chondrocytes of hypertrophic and proliferating zones, as well as in osteocytes and osteoblast-like cells of the ossification zone. In group III, only limited PTN expression was observed in osteocytes. RPTPβ/ζ expression was increased mainly in group 0, but also in group I, in all types of cells. Low intensity RPTPβ/ζ immunostaining was observed in groups II and III. Collectively, PTN and RPTPβ/ζ are expressed in spinal deformities caused by mechanical loading, and their expression depends on the type and severity of the applied strain. © 2015.
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- 2016
33. Thalassemia-associated osteoporosis: a systematic review on treatment and brief overview of the disease
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Dede, A.D. Trovas, G. Chronopoulos, E. Triantafyllopoulos, I.K. Dontas, I. Papaioannou, N. Tournis, S.
- Abstract
Summary: Thalassemia-associated osteoporosis constitutes a major complication in patients with thalassemia. This review presents the existing studies on the treatment of thalassemia-associated osteoporosis and discusses the management of this debilitating complication. A brief presentation of the disease characteristics and pathogenetic mechanisms is also provided. The life expectancy of patients with thalassemia has increased markedly in recent years resulting in the aging of the population and the emergence of new comorbidities. The majority of patients with thalassemia have low bone mineral density and experience lifelong fracture rates as high as 71 %. The pathogenesis of thalassemia-associated osteoporosis (TAO) is multifactorial with anemia and iron overload playing crucial role in its development. Data concerning the prevention and treatment of TAO are extremely limited. We performed a literature research in Pubmed and Scopus to identify interventional studies evaluating the effects of various agents on TAO. Seventeen studies were retrieved. We present the results of these studies as well as a brief overview of TAO including presentation, pathogenesis, and management. Most of the studies identified are of poor quality, are not randomized controlled, and include small number of participants. There are no data concerning effects on fracture rates. Bisphosphonates are the most widely studied agents and among them zoledronic acid is the most well studied. Hormone replacement treatment (HRT) shows beneficial but small effects. Denosumab and strontium ranelate have each been evaluated in only a single study, while there are no data about the effects of anabolic agents. Given the increased life expectancy and the increase in fracture rates with age, more data about the management of TAO are warranted. Moreover, due to the need for lifelong management starting at young age, careful treatment plans which may include sequential treatment may often be required. However, currently, there are no relevant data available. © 2016, International Osteoporosis Foundation and National Osteoporosis Foundation.
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- 2016
34. First summary of studies carried out on the grey mullet (Mugil cephalus) in the EU project: diversify
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Koven, W, Rosenfeld, H, Fauvel, Christian, Nixon, O, Meiri-ashkenazi, I, Bitan, A, Robles, R, Kotzamanis, Y, Shafran, G, and Papaioannou, N
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endocrine system ,urogenital system - Abstract
The deliverable (D7.1) of WP7 “Establishment of a Computer Assisted Sperm Analysis (CASA) for the evaluation of grey mullet sperm” has been submitted. Preliminary analyses show that mullet sperm motility pattern is not similar to that of sea bass (Dicentrarchus labrax) or rainbow trout (Oncorhynchus mykiss) in terms of velocity as well as motility duration (ca 1 min; Fig. 1a). Our preliminary results, indicate that the major bio-technical settings, dilution of sperm, quality of activation and mastering of video recordings have been determined and can now be applied to experimental protocols. Since fish sperm quality is usually assessed through subjective observation, in terms of motility classes and duration, statistical analysis becomes less precise. The current results will help improve assessment of the effect of different treatments on reproductive performances of mullet males.
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- 2015
35. Persistence, adherence, and medication-taking behavior in women with postmenopausal osteoporosis receiving denosumab in routine practice in Germany, Austria, Greece, and Belgium: 12-month results from a European non-interventional study
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Hadji, P. Papaioannou, N. Gielen, E. Feudjo Tepie, M. Zhang, E. Frieling, I. Geusens, P. Makras, P. Resch, H. Möller, G. Kalouche-Khalil, L. Fahrleitner-Pammer, A.
- Abstract
Summary: Persistence with and adherence to osteoporosis therapy are critical for fracture reduction. This non-interventional study is evaluating medication-taking behavior of women with postmenopausal osteoporosis (PMO) receiving denosumab in Germany, Austria, Greece, and Belgium. Patients were representative of the PMO population and highly persistent with and adherent to denosumab at 12 months. Introduction: Persistence with and adherence to osteoporosis therapy are important for optimal treatment efficacy, namely fracture reduction. This ongoing, non-interventional study will evaluate medication-taking behavior of women with postmenopausal osteoporosis (PMO) receiving denosumab in routine practice in four European countries. Methods: The study enrolled women who had been prescribed subcutaneous denosumab (60 mg every 6 months) in accordance with prescribing information and local guidelines. Persistence was defined as receiving the subsequent injection within 6 months + 8 weeks of the previous injection. Adherence was defined as receiving two consecutive injections within 6 months ± 4 weeks of each other. Medication coverage ratio (MCR) was calculated using the time a patient was covered with denosumab, as assessed from prescription records. Treatment was assigned prior to and independently of enrollment; outcomes are recorded during routine practice. Results: These planned 12-month interim analyses included data from 1500 patients from 141 sites. Mean age was 66.4–72.4 years, mean baseline total hip T-scores ranged from −2.0 to −2.1 and femoral neck T-scores from −2.2 to −2.6, and 30.7–62.1 % of patients had prior osteoporotic fracture. Persistence was 87.0–95.3 %, adherence 82.7–89.3 %, and MCR 91.3–95.4 %. In a univariate analysis, increased age, decreased mobility, and increased distance to the clinic were associated with significantly decreased persistence; parental history of hip fracture was associated with significantly increased persistence. Conclusions: These data extend the real-world evidence regarding persistence with and adherence to denosumab, both of which are critical for favorable clinical outcomes, including fracture risk reduction. © 2015, The Author(s).
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- 2015
36. Transient carotid ischemia as a remote conditioning stimulus for myocardial protection in anesthetized rabbits: Insights into intracellular signaling
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Andreadou, I. Bibli, S.-I. Mastromanolis, E. Zoga, A. Efentakis, P. Papaioannou, N. Farmakis, D. Kremastinos, D.Th. Iliodromitis, E.K.
- Abstract
Background: We investigated the effectiveneß of perconditioning (Perc) applied at different time points along with the role of RISK, SAFE, STAT5 and eNOS pathways. Methods and results: Anesthetized rabbitswere subjected to 30-min ischemia/3-hour reperfusion. Perc, consisted of 4 cycles of 1-min ischemia/reperfusion, was applied in the carotid artery at different time points. Perc was started and ended during ischemia, started during ischemia and ended at the beginning of reperfusion, started at the end of ischemia and ended at reperfusion and started and ended during reperfusion. The PI3K inhibitor wortmannin, or the JAK-2 inhibitor AG490, was also applied and the infarct size was aßeßed. In another series aßigned to the previous groups, the phosphorylation of Akt, PI3K, ERKs1/2, GSK3β, STAT3, and STAT5 was evaluated. All Perc groups had smaller infarction compared to those without Perc, independently of PI3K or JAK-2 inhibition. STAT5 was the only molecule that was phosphorylated in parallel with cardioprotection. Since Src and angiotensin II mediate the STAT5 pathway, we administered the Scr inhibitor PP1 and the angiotensin II receptor antagonist valsartan. PP1 and valsartan prevented STAT5 phosphorylation, but did not abrogate the effect of Perc. Furthermore, the NOS inhibitor L-NAME was administered and abrogated the infarct size limiting effect of Perc. In parallel, the expreßion of cleaved caspase-3 was elevated only in the control and Perc-A-LNAME groups. Conclusion: Perc reduces infarction independently of RISK, SAFE and STAT5 pathways. Src kinase and angiotensin II play a predominant role in STAT5 activation. eNOSmay protect themyocardiumthrough inhibition of apoptosis. © 2015 Elsevier Ireland Ltd. All rights reserved.
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- 2015
37. Vertebral fracture assessment: Current research status and application in patients with kyphoplasty
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Drampalos, E. Nikolopoulos, K. Baltas, C. Balanika, A. Galanos, A. Papaioannou, N. Pneumaticos, S.
- Abstract
Imaging of the spine is of paramount importance for the recognition of osteoporotic vertebral fractures (VFs), and standard radiography (SR) of the spine is the suggested diagnostic method but is not routinely used because of the cost and radiation exposure considerations. VF assessment (VFA) is an efficient, low radiation method for identifying VFs at the time of bone mineral density (BMD) measurement. Prediction models used to indicate the need for VFA may have little predictive power in subspecialty referral populations such as rheumatologic patients or patients who underwent kyphoplasty. Rheumatologic patients are frequently at increased risk for VFs, and VFA should be performed on an individual basis, also taking in account the guidelines for the general population. Kyphoplasty is a new minimal invasive procedure for the treatment of VFs and is being performed with increasing frequency. Following kyphoplasty, there may be a risk of new VFs in adjacent vertebrae. The assessment and follow-up of patients who underwent kyphoplasty requires repetitive X-ray imaging with the known limitations of SR. Thus, VFA may facilitate the evaluation of VFs in these patients because most of the kyphoplasty patients would fulfill the criteria. In a pilot study, we measured the BMD and performed VFA in 28 patients treated with kyphoplasty. Ratios of anterior to posterior (A/P) and middle to posterior (M/P) height were measured, and Genant's method was used to classify vertebrae accordingly. Intraobserver and interobserver reliability for A/P, M/P and the Genant's method were determined. Only 1 patient did not meet the criteria for VFA. Of the 364 available vertebrae, 295 could be analyzed. Most missing data (concerning 69 vertebrae) occurred in the upper thoracic region. Three of the 69 non-eligible vertebrae were lumbar vertebrae with cement leakage from the kyphoplasty procedure. In our hands, VFA was highly reproducible, demonstrating very good agreement in terms of intraobserver and interobserver reliability. Agreement was very good on the vertebral level, "vertebrae with kyphoplasty" level and "2 above and 1 below the kyphoplasty vertebrae" level. The application of Genant's method to these patients also resulted in perfect agreement. We believe that the potential value of VFA in patients treated with kyphoplasty requires further evaluation, particularly comparing VFA with SR and performing a longitudinal follow-up. More research will help to adopt care processes that determine which patients require VFA and how often VFA should be performed, while also considering the impact of this technique on the cost of healthcare organizations. © The Author(s) 2015. Published by Baishideng Publishing Group Inc.
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- 2015
38. Effects of teriparatide retreatment in a patient with β-thalassemia major
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Tournis, S. Dede, A.D. Savvidis, C. Triantafyllopoulos, I.K. Kattamis, A. Papaioannou, N.
- Abstract
BACKGROUND Bone disease is a frequent complication of β-thalassemia major (β-ΤΜ) and its etiology is multifactorial. Marrow expansion, chronic hypoxia, endocrine complications, and iron overload caused chiefly by chronic transfusion treatment are significant factors affecting skeletal health. Bone disease is prevalent even among patients on regular transfusions and adequate iron chelation. The life expectancy of patients with β-thalassemia has increased during the past decade and so, nowadays, patients with thalassemia-associated bone disease (TBD) often require long-term management. There are limited data concerning their pharmacologic treatment. Bisphosphonates represent the most widely studied agents in such patients and there are no published studies about the effects of anabolic treatment. Retreatment with teriparatide has only occasionally been studied in patients with osteoporosis. CASE REPORT We present a male adult patient with β-ΤΜ with a history of low bone mass and multiple vertebral fractures, who required sequential treatment for his longstanding bone disease. He had exhibited considerable, albeit delayed, response to a course of teriparatide treatment for 18 months but subsequently, and while on alendronate, sustained an insufficiency fracture at the left ischiopubic ramus. A second trial of teriparatide treatment resulted in further remarkable increase in total hip and femoral neck bone mineral density. We present the patient's response to sequential treatment during an 8-year follow-up. CONCLUSION Teriparatide could represent an alternative treatment for adults with TBD especially when long-term, sequential treatment is needed. Although there are limited data concerning retreatment, in selected cases, this might be considered. © 2015 AABB.
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- 2015
39. Prospective study of spinal orthoses in women
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Dionyssiotis, Y. Trovas, G. Thoma, S. Lyritis, G. Papaioannou, N.
- Abstract
Background: There are not many clinical trials investigating the efficiency and compliance of using spinal orthoses in the management of osteoporosis. Objectives: The purpose of this study was to investigate the effect of long-term use and the compliance of spinal orthoses in postmenopausal women with vertebral fractures. Study design: Clinical trial of spinal orthoses in postmenopausal women. Methods: Women were separated into groups wearing different types of orthoses (Spinomed, Osteomed, Spinomed active, and Spine-X). Isometric maximum strength of trunk muscles (F/Wabdominals-extensors) was calculated and back pain was assessed in all women. In addition, women completed a compliance questionnaire about the use of the orthoses. Results: Spinomed decreased pain (p = 0.001) and increased trunk muscle strength (F/Wabdominals, p = 0.005 and F/Wextensors, p = 0.003, respectively). The compliance of wearing an orthosis for 6 months was 66%. Conclusion: The results suggest that orthoses could be an effective intervention for back pain and muscle strengthening in osteoporotic women. Clinical relevance In women with established osteoporosis, wearing Spinomed orthosis for at least 2 h/day for 6 months decreased back pain significantly and increased personal isometric trunk muscle strength. All spinal orthoses could be valuable instruments to help all requested rehabilitation programs like spine muscles' strengthening and postural correct behavior, but only when used properly. © 2014 The International Society for Prosthetics and Orthotics.
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- 2015
40. Volumetric bone mineral density and bone geometry assessed by peripheral quantitative computed tomography in women with differentiated thyroid cancer under TSH suppression
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Tournis, S. Antoniou, J.D. Liakou, C.G. Christodoulou, J. Papakitsou, E. Galanos, A. Makris, K. Marketos, H. Nikopoulou, S. Tzavara, I. Triantafyllopoulos, I.K. Dontas, I. Papaioannou, N. Lyritis, G.P. Alevizaki, M.
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musculoskeletal diseases - Abstract
Objective TSH suppression therapy in patients with differentiated thyroid cancer (DTC) has been associated with adverse effects on areal bone mineral density (aBMD) only in postmenopausal women. The purpose of study was to examine the effect of TSH suppression therapy on skeletal integrity using peripheral quantitative computed tomography (pQCT) at the radius and tibia in pre- and postmenopausal women with DTC and controls. Study design and patients Subjects included 80 women with DTC (40 pre- and 40 postmenopausal) and 89 (29 and 60, respectively) controls. pQCT was performed at the radius and tibia, Dual-energy X-ray absorptiometry (DXA) at the hip and lumbar spine, while samples were taken for calciotropic hormones and bone markers. Results No differences were observed concerning aBMD by DXA. In premenopausal women, there were no significant differences concerning vBMD, while cortical thickness was higher at the radius in patients with DTC (P < 0·01) compared with controls. In postmenopausal women with DTC trabecular bone mineral content (BMC), area and vBMD were lower at the radius (all P < 0·05), while at the tibia trabecular BMC and vBMD were lower at the mixed transition zone (14% from the distal end, P < 0·05) compared with controls. Cortical thickness was lower at the radius (P < 0·01) in postmenopausal patients compared with controls. Serum CTX was higher in postmenopausal women with DCT (P < 0·01), while in premenopausal patients, parathyroid hormone (PTH) was lower (P = 0·01) compared with controls. Conclusions TSH suppression therapy is associated with higher bone resorption only in postmenopausal women; this adversely affects trabecular and cortical bone properties especially at nonweight-bearing sites such as the radius. © 2014 John Wiley & Sons Ltd.
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- 2015
41. Denosumab compared with risedronate in postmenopausal women suboptimally adherent to alendronate therapy: Efficacy and safety results from a randomized open-label study
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Roux, C. Hofbauer, L. C. Ho, P. R. Wark, J. D. and Zillikens, M. C. Fahrleitner-Pammer, A. Hawkins, F. Micaelo, M. Minisola, S. Papaioannou, N. Stone, M. Ferreira, I. and Siddhanti, S. Wagman, R. B. Brown, J. P.
- Abstract
Denosumab has been shown to reduce new vertebral, nonvertebral, and hip fractures in postmenopausal women with osteoporosis. In subjects who were treatment-naive or previously treated with alendronate, denosumab was associated with greater gains in bone mineral density (BMD) and decreases in bone turnover markers when compared with alendronate-treated subjects. This trial was designed to compare the efficacy and safety of denosumab with risedronate over 12 months in postmenopausal women who transitioned from daily or weekly alendronate treatment and were considered to be suboptimally adherent to therapy. In this randomized, open-label study, postmenopausal women aged >= 55 years received denosumab 60 mg subcutaneously every 6 months or risedronate 150 mg orally every month for 12 months. Endpoints included percentage change from baseline in total hip BMD (primary endpoint), femoral neck, and lumbar spine BMD at month 12, and percentage change from baseline in sCTX-1 at months 1 and 6. Safety was also assessed. A total of 870 subjects were randomized (435, risedronate; 435, denosumab) who had a mean (SD) age of 67.7 (6.9) years, mean (SD) BMD T-scores of -1.6 (0.9), -1.9 (0.7), and -2.2 (1.2) at the total hip, femoral neck, and lumbar spine, respectively, and median sCTX-1 of 03 ng/mL at baseline. At month 12, denosumab significantly increased BMD compared with risedronate at the total hip (2.0% vs 0.5%), femoral neck (1.4% vs 0%), and lumbar spine (3.4% vs 1.1%; p
- Published
- 2014
42. Enhancement of bone regeneration with the combination of platelet-rich fibrin and synthetic graft
- Author
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Nacopoulos, C. Dontas, I. Lelovas, P. Galanos, A. Vesalas, A.-M. Raptou, P. Mastoris, M. Chronopoulos, E. Papaioannou, N.
- Abstract
Introduction: Platelet-rich fibrin (PRF) is a relatively new developed platelet concentrate with several benefits over platelet-rich plasma. The aim of this study was to compare healing properties of PRF and its combination with a ceramic synthetic material (graft) composed of hydroxyapatite and b-tricalcium phosphate in an animal model. Methods: A bone deficit was surgically created in each femoral condyle of 15 New Zealand white rabbits. In each animal, 1 limb had (a) PRF only and the other (b) PRF plus synthetic graft material randomly implanted. Experimental animals were killed 3 months postoperatively. Histological and radiological examinations were made by means of computed tomography and peripheral quantitative computed tomography. Results: Mean density of the healed bone was statistically significantly greater when synthetic material was used (P < 0.0005). Moreover, combination of PRF with the synthetic material resulted in more cortical and subcortical bone formation (P = 0.038 and P = 0.037, respectively). Conclusions: The addition of the ceramic material significantly increased the formation of new bone, providing a better substrate for bone regeneration. ©2014 by Mutaz B. Habal, MD.
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- 2014
43. Prospective randomised controlled trial of an intramedullary nail versus a sliding hip screw for intertrochanteric fractures of the femur
- Author
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Aktselis, I. Kokoroghiannis, C. Fragkomichalos, E. Koundis, G. Deligeorgis, A. Daskalakis, E. Vlamis, J. Papaioannou, N.
- Abstract
Purpose: The purpose of this prospective randomised trial was to assess whether an intramedullary nail is superior to a sliding hip screw in the treatment of multifragmentary intertrochanteric fractures Methods: Eighty patients with a 31-A2.2 or A2.3 Arbeitsgemeinschaft für Osteosynthesefragen/Orthopaedic Trauma Association (AO/OTA) intertrochanteric fracture were randomly allocated to fixation with either the Gamma nail or the AMBI sliding hip screw device. Results: All patients were followed up at one, three, six and 12 months postoperatively, except for nine who died. There was no statistical difference in Parker mobility score between groups. The Gamma nail group had significantly higher Barthel Index and EuroQol-5D (EQ-5D) scores than the AMBI group at 12 months. At the same time, the EQ-5D score had returned to its pre-operative values in the Gamma nail group but not in the AMBI group. There were no differences in mortality, radiation time and hospital stay. Duration of the operation, incision length and hip pain occurrence were significantly less in the Gamma nail group. Conclusions: Few failures occur when unstable 31-A2.2 and A2.3 AO/OTA fractures are fixed with a sliding hip screw. Nevertheless, an intramedullary nail seems superior in reconstituting patients to their pre-operative state. © 2013 Springer-Verlag Berlin Heidelberg.
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- 2014
44. Effect of parathyroidectomy versus risedronate on volumetric bone mineral density and bone geometry at the tibia in postmenopausal women with primary hyperparathyroidism
- Author
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Tournis, S. Fakidari, E. Dontas, I. Liakou, C. Antoniou, J. Galanos, A. Marketou, H. Makris, K. Katsalira, K. Trovas, G. Lyritis, G.P. Papaioannou, N.
- Subjects
musculoskeletal diseases ,musculoskeletal system - Abstract
The objective of the study was to evaluate the effect of parathyroidectomy (PTX) versus 35 mg once-weekly (ow) risedronate administration on volumetric bone mineral density (vBMD) and bone geometry at the tibia in postmenopausal women with primary hyperparathyroidism (PHPT). Our open-label prospective observational study included 32 postmenopausal women with PHPT as the study group: 16 underwent PTX and 16 were treated with 35 mg ow risedronate for 2 years. We assessed areal BMD (aBMD) by DXA, and vBMD and bone mineral content (BMC) (cortical and trabecular area) by peripheral quantitative computed tomography (pQCT) at the tibia at baseline and at 2 years. Risedronate did not result in any significant change on vBMD and structural pQCT indices. PTX resulted in significant increase in trabecular (trab) BMC (6.44 %) and vBMD (4.64 %), with percent increase being significantly higher than risedronate (p < 0.05). At cortical sites, there was no significant change following PTX. However, the percent change in cortical (cort) vBMD was higher following PTX versus risedronate (0.39 % vs. -0.26 %, p < 0.05). In conclusion, in postmenopausal women with PHPT, PTX is superior to ow risedronate, in terms of improvement of trabecular mineralization and vBMD at the tibia, whereas the effect at cortical sites is less pronounced. © 2013 The Japanese Society for Bone and Mineral Research and Springer.
- Published
- 2014
45. Early changes in biochemical markers of bone formation during teriparatide therapy correlate with improvements in vertebral strength in men with glucocorticoid-induced osteoporosis
- Author
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Farahmand, P. Marin, F. Hawkins, F. Moericke, R. Ringe, J. D. Glueer, C. -C. Papaioannou, N. Minisola, S. and Martinez, G. Nolla, J. M. Niedhart, C. Guanabens, N. and Nuti, R. Martin-Mola, E. Thomasius, F. Pena, J. Graeff, C. Kapetanos, G. Petto, H. Gentzel, A. Reisinger, A. and Zysset, P. K.
- Abstract
Changes of the bone formation marker PINP correlated positively with improvements in vertebral strength in men with glucocorticoid-induced osteoporosis (GIO) who received 18-month treatment with teriparatide, but not with risedronate. These results support the use of PINP as a surrogate marker of bone strength in GIO patients treated with teriparatide. Introduction To investigate the correlations between biochemical markers of bone turnover and vertebral strength estimated by finite element analysis (FEA) in men with GIO. Methods A total of 92 men with GIO were included in an 18-month, randomized, open-label trial of teriparatide (20 mu g/day, n=45) and risedronate (35 mg/week, n=47). High-resolution quantitative computed tomography images of the 12th thoracic vertebra obtained at baseline, 6 and 18 months were converted into digital nonlinear FE models and subjected to anterior bending, axial compression and torsion. Stiffness and strength were computed for each model and loading mode. Serum biochemical markers of bone formation (amino-terminal-propeptide of type I collagen [PINP]) and bone resorption (type I collagen cross-linked C-telopeptide degradation fragments [CTx]) were measured at baseline, 3 months, 6 months and 18 months. A mixed-model of repeated measures analysed changes from baseline and between-group differences. Spearman correlations assessed the relationship between changes from baseline of bone markers with FEA variables. Results PINP and CTx levels increased in the teriparatide group and decreased in the risedronate group. FEA-derived parameters increased in both groups, but were significantly higher at 18 months in the teriparatide group. Significant positive correlations were found between changes from baseline of PINP at 3, 6 and 18 months with changes in FE strength in the teriparatide-treated group, but not in the risedronate group. Conclusions Positive correlations between changes in a biochemical marker of bone formation and improvement of biomechanical properties support the use of PINP as a surrogate marker of bone strength in teriparatide-treated GIO patients.
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- 2013
46. Physical activity is associated with bone geometry of premenarcheal girls in a dose-dependent manner
- Author
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Michalopoulou, M. Kambas, A. Leontsini, D. Chatzinikolaou, A. Draganidis, D. Avloniti, A. Tsoukas, D. Michopoulou, E. Lyritis, G.P. Papaioannou, N. Tournis, S. Fatouros, I.G.
- Abstract
Objective To determine the relationship between habitual physical activity (PA) level and peripheral qualitative computed tomography-determined quantitative tibia characteristics of premenarcheal girls. Methods Premenarcheal girls matched for age (10-13 years), bone age and maturity level were assigned into: a) low PA group (LPA, n = 25), b) moderate PA group (MPA, n = 17), and c) high PA group (HPA, n = 18). Participants' daily dietary intake, tibia's geometry and serum levels of calcium and vitamin D were assessed. Results Premenarcheal girls demonstrating HPA exhibited greater pericortical thickness, cross-sectional area (CSA) and bone mineral content (BMC) (p
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- 2013
47. Cross-Exercise on Quadriceps Deficit after ACL Reconstruction
- Author
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Papandreou, M. Papathanasiou, G. Spyropoulos, P. Billis, E. Papaioannou, N.
- Subjects
musculoskeletal system - Abstract
A few studies concerning the improvement of quadriceps muscle strength deficit (QD) at an early stage following anterior cruciate ligament (ACL) reconstruction have been conducted whereas, ACL rehabilitation protocols based on contralateral quadriceps strength (QS) do not exist. Given these, the goals of our study were (1) to evaluate the effects of cross-eccentric exercise (CEE) on QD on ACL reconstructed knees, and (2) to explore any changes in QD following CEE provided at the frequencies of 3 or 5 times per week. For this study, 42 ACL-reconstructed patients were randomly assigned into 3 groups, two experimental and one control and followed an 8-week rehabilitation program. Additionally, the experimental groups received CEE for 3 and 5 days per week for 8 weeks in their uninjured knees. QS was evaluated with an isokinetic/isometric test, at 60 degrees of knee flexion of both limbs before and after completion of CEE. Twofactor ANOVA showed a significant improvement of QD between groups (F = 5.16, p = 0.01) after CEE completion on ACL reconstructed knees. Statistically significant results arose from the 3 days per week (D = 18.60, p = 0.01) and 5 days per week (D = 15.12, p = 0.04) experimental groups, whereas the control group did not yield any statistically significant differences. CEE used as an adjunct to the ACL traditional rehabilitation program at the weekly frequencies of 3 and 5 times at the early stage of reconstruction significantly improved QD. © 2012, Thieme Medical Publishers. All rights reserved.
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- 2012
48. Application of FRAX algorithm in a sample of Greek male population - A preliminary study
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Stathopoulos, I. Trovas, G. Lampropoulou-Adamidou, K. and Zafeiris, C. Tournis, S. Katsalira, A. Galanos, A. and Papaioannou, N.
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- 2012
49. Correlation between bone mass index and fracture risk in a Greek female population
- Author
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Lampropoulou-Adamidou, K. Trovas, G. Stathopoulos, I. P. and Zafeiris, C. Tournis, S. Katsalira, A. Galanos, A. and Papaioannou, N. A.
- Published
- 2012
50. Hemolytic-uremic syndrome, malignant hypertension and IgA nephropathy: Successful treatment with plasma exchange therapy
- Author
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Pipili, C. Pantelias, K. Papaioannou, N. Paraskevakou, H. Grapsa, E.
- Abstract
A young patient with hemolytic-uremic syndrome and malignant hypertension with serious deterioration of renal function is described whose biopsy specimen showed additional IgA mesangial deposits. The patient responded to steroid treatment and to plasma exchange therapy without the need of hemodialysis sessions. In the following years, he achieved clinical remission and his blood pressure was in normal ranges without any further complications. IgA glomerulonephritis is rarely associated to hemolytic-uremic syndrome and malignant hypertension, with only a few previously described cases. We present an overview of potential pathophysiological connections between these diseases. © 2012 Elsevier Ltd.
- Published
- 2012
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