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result(s) for
"Marinos, Georgios"
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Medical education challenges and innovations during COVID-19 pandemic
by
Papapanou, Michail
,
Routsi, Eleni
,
Marinos, Georgios
in
Clinical medicine
,
Coronaviruses
,
COVID-19
2022
COVID-19 pandemic has undoubtedly disrupted the well-established, traditional structure of medical education. Τhe new limitations of physical presence have accelerated the development of an online learning environment, comprising both of asynchronous and synchronous distance education, and the introduction of novel ways of student assessment. At the same time, this prolonged crisis had serious implications on the lives of medical students including their psychological well-being and the impact on their academic trajectories. The new reality has, on many occasions, triggered the ‘acting up’ of medical students as frontline healthcare staff, which has been perceived by many of them as a positive learning and contributing experience, and has led to a variety of responses from the educational institutions. All things considered, the urgency for rapid and novel adaptations to the new circumstances has functioned as a springboard for remarkable innovations in medical education,including the promotion of a more “evidence-based” approach.
Journal Article
Defining the nutritional input for genome-scale metabolic models: A roadmap
by
Kaleta, Christoph
,
Marinos, Georgios
,
Waschina, Silvio
in
Amino acids
,
Biology
,
Biology and Life Sciences
2020
The reconstruction and application of genome-scale metabolic network models is a central topic in the field of systems biology with numerous applications in biotechnology, ecology, and medicine. However, there is no agreed upon standard for the definition of the nutritional environment for these models. The objective of this article is to provide a guideline and a clear paradigm on how to translate nutritional information into an in-silico representation of the chemical environment. Step-by-step procedures explain how to characterise and categorise the nutritional input and to successfully apply it to constraint-based metabolic models. In parallel, we illustrate the proposed procedure with a case study of the growth of Escherichia coli in a complex nutritional medium and show that an accurate representation of the medium is crucial for physiological predictions. The proposed framework will assist researchers to expand their existing metabolic models of their microbial systems of interest with detailed representations of the nutritional environment, which allows more accurate and reproducible predictions of microbial metabolic processes.
Journal Article
In vitro interaction network of a synthetic gut bacterial community
2022
A key challenge in microbiome research is to predict the functionality of microbial communities based on community membership and (meta)-genomic data. As central microbiota functions are determined by bacterial community networks, it is important to gain insight into the principles that govern bacteria-bacteria interactions. Here, we focused on the growth and metabolic interactions of the Oligo-Mouse-Microbiota (OMM
12
) synthetic bacterial community, which is increasingly used as a model system in gut microbiome research. Using a bottom-up approach, we uncovered the directionality of strain-strain interactions in mono- and pairwise co-culture experiments as well as in community batch culture. Metabolic network reconstruction in combination with metabolomics analysis of bacterial culture supernatants provided insights into the metabolic potential and activity of the individual community members. Thereby, we could show that the OMM
12
interaction network is shaped by both exploitative and interference competition in vitro in nutrient-rich culture media and demonstrate how community structure can be shifted by changing the nutritional environment. In particular,
Enterococcus faecalis
KB1 was identified as an important driver of community composition by affecting the abundance of several other consortium members in vitro. As a result, this study gives fundamental insight into key drivers and mechanistic basis of the OMM
12
interaction network in vitro, which serves as a knowledge base for future mechanistic in vivo studies.
Journal Article
Virtual Colon: spatiotemporal modeling of metabolic interactions in a computational colonic environment
by
Marinos, Georgios
,
Zimmermann, Johannes
,
Taubenheim, Jan
in
Colon - metabolism
,
Colon - microbiology
,
Computer Simulation
2026
Interactions between the human body and gut microbes are crucial for health and disease. We present the Virtual Colon, an extension of the individual-based microbiome modeling approach BacArena that mimics key features of the colon, including the crypts, mucus layers, lumen, and fluid flow. Using this model, we simulate gut environments including host cells with bacterial species alone and with a simplified gut microbiota (SIHUMIx). These simulations reveal patterns of host-microbe and microbe-microbe interactions that align with known findings. A key strength of the Virtual Colon is its ability to show how interactions unfold over time and space, offering new insights beyond traditional modeling approaches. The Virtual Colon is freely available and can be adapted to other structured biological environments ( http://www.github.com/maringos/VirtualColon ).
Journal Article
Assessment of Vaccination Status in Professional Football Players in Low Categories in Greece
by
Anyfantis, Ioannis
,
Marinos, Georgios
,
Rachiotis, Georgios
in
chief medical officers
,
Communication
,
football players
2022
Background: There are limited data on the vaccination practices of footballers in low professional categories in Greece and Europe. The aim of this study was to investigate the vaccination practices followed by the medical staff of the low professional football categories in Central Greece. Methods: A questionnaire was developed and included questions on the vaccination practices of football players. The participants were chief medical officers of the fifteen low-category football teams in Central Greece. Overall, 10 out of 15 chief medical officers participated (response rate: 67%). Results: All participants recommended only the tetanus monovalent vaccine in cases with deep trauma of athletes. Influenza, pneumococcal vaccine, and Hepatitis A and B vaccines were not recommended by the medical officers. This was also the case for measles, mumps, rubella (MMR) vaccine and meningococcal vaccine with strains A, C, Y, W. Participants reported the lack of specific guidelines for vaccination in professional footballers. Conclusions: The recent study showed poor vaccination practices in low categories of professional football teams in Central Greece. The qualitative view of the respondents revealed the importance of the absence of guidelines on vaccination of football players.
Journal Article
Impaired left ventricular deformation and ventricular-arterial coupling in post-COVID-19: association with autonomic dysregulation
by
Papaioannou, Theodore G.
,
Siasos, Gerasimos
,
Tousoulis, Dimitris
in
Abnormalities
,
Aorta
,
Autonomic nervous system
2023
Coronavirus disease-19 (COVID-19) has extended implications namely the long COVID-19 syndrome. We assessed over-time changes in left ventricular (LV) function, aortic stiffness, autonomic function, and ventricular-arterial coupling (VAC) in post-COVID-19 patients. We followed 34 post-COVID-19 subjects, up to 6 months post-hospital discharge. Subjects without COVID-19 served as control. We evaluated LV global longitudinal strain (LV-GLS), arterial stiffness [carotid-femoral pulse wave velocity (cf-PWV)], and heart rate variability -standard deviation of normal RR intervals (SDNN). VAC was estimated as the ratio of cf-PWV to LV-GLS. Post-COVID-19 individuals (1-month post-hospital discharge) presented with impaired LV-GLS [−18.4%(3.1) vs. −22.0%(2.7),
P
< 0.001], cf-PWV [12.1 m/s (3.2) vs. 9.6 m/s (1.9),
P
< 0.001], SDNN [111.3 ms (22.6) vs. 147.2 ms (14.0),
P
< 0.001], and VAC [−0.68 (0.22) vs. −0.44 (0.10),
P
< 0.001] compared to control. LV-GLS, SDNN, and VAC improved at the 6-month follow-up however they did not reach control levels. In post-COVID-19 subjects, SDNN and VAC were correlated at the 1-month (
R
= 0.499,
P
= 0.003) and 6-month (
R
= 0.372,
P
= 0.04) follow-up. Long COVID-19 syndrome was associated with impaired LV-GLS, SDNN, and VAC. Post-COVID-19 subjects presented with autonomic dysregulation associated with aortic stiffness, ventricular-arterial impairment, and LV dysfunction, even 6-months post-hospital discharge. These abnormalities may be related to the presence of long COVID-19 syndrome.
Graphical abstract
Journal Article
Reported COVID-19 Vaccination Coverage and Associated Factors among Members of Athens Medical Association: Results from a Cross-Sectional Study
by
Symvoulakis, Emmanouil K.
,
Pouletidis, Theodoros
,
Papagiannis, Dimitrios
in
Coronaviruses
,
COVID-19
,
COVID-19 vaccines
2021
There are limited data on the prevalence and determinants of COVID-19 vaccination coverage among physicians. A cross-sectional, questionnaire-based, online study was conducted among the members of the Athens Medical Association (I.S.A.) over the period 25 February to 13 March 2021. All members of I.S.A. were invited to participate in the anonymous online survey. A structured, anonymous questionnaire was used. Overall, 1993 physicians participated in the survey. The reported vaccination coverage was 85.3%. The main reasons of no vaccination were pending vaccination appointment followed by safety concerns. Participants being informed about the COVID-19 vaccines by social media resulted in lower COVID-19 vaccination coverage than health workers being informed by other sources. Logistic regression analysis demonstrated that no fear over COVID-19 vaccination-related side effects, history of influenza vaccination for flu season 2020–2021, and the perception that the information on COVID-19 vaccination from the national public health authorities is reliable, were independent factors of reported COVID-19 vaccination coverage. Our results demonstrate a considerable improvement of the COVID-19 vaccination uptake among Greek physicians. The finding that participants reported high reliability of the information related to COVID-19 vaccination provided by the Greek public health authorities is an opportunity which should be broadly exploited by policymakers in order to combat vaccination hesitancy, and further improve COVID-19 vaccination uptake and coverage among physicians/HCWs, and the general population.
Journal Article
Discovery of novel community-relevant small proteins in a simplified human intestinal microbiome
by
Riesbeck, Sarah
,
Poehlein, Anja
,
Daniel, Rolf
in
Bacteria
,
Bacteria - classification
,
Bacteria - genetics
2021
Background
The intestinal microbiota plays a crucial role in protecting the host from pathogenic microbes, modulating immunity and regulating metabolic processes. We studied the simplified human intestinal microbiota (SIHUMIx) consisting of eight bacterial species with a particular focus on the discovery of novel small proteins with less than 100 amino acids (= sProteins), some of which may contribute to shape the simplified human intestinal microbiota. Although sProteins carry out a wide range of important functions, they are still often missed in genome annotations, and little is known about their structure and function in individual microbes and especially in microbial communities.
Results
We created a multi-species integrated proteogenomics search database (iPtgxDB) to enable a comprehensive identification of novel sProteins. Six of the eight SIHUMIx species, for which no complete genomes were available, were sequenced and de novo assembled. Several proteomics approaches including two earlier optimized sProtein enrichment strategies were applied to specifically increase the chances for novel sProtein discovery. The search of tandem mass spectrometry (MS/MS) data against the multi-species iPtgxDB enabled the identification of 31 novel sProteins, of which the expression of 30 was supported by metatranscriptomics data. Using synthetic peptides, we were able to validate the expression of 25 novel sProteins. The comparison of sProtein expression in each single strain versus a multi-species community cultivation showed that six of these sProteins were only identified in the SIHUMIx community indicating a potentially important role of sProteins in the organization of microbial communities. Two of these novel sProteins have a potential antimicrobial function. Metabolic modelling revealed that a third sProtein is located in a genomic region encoding several enzymes relevant for the community metabolism within SIHUMIx.
Conclusions
We outline an integrated experimental and bioinformatics workflow for the discovery of novel sProteins in a simplified intestinal model system that can be generically applied to other microbial communities. The further analysis of novel sProteins uniquely expressed in the SIHUMIx multi-species community is expected to enable new insights into the role of sProteins on the functionality of bacterial communities such as those of the human intestinal tract.
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Video abstract
Journal Article
Life-long microbiome rejuvenation improves intestinal barrier function and inflammaging in mice
2025
Background
Alterations in the composition and function of the intestinal microbiota have been observed in organismal aging across a broad spectrum of animal phyla. Recent findings, which have been derived mostly in simple animal models, have even established a causal relationship between age-related microbial shifts and lifespan, suggesting microbiota-directed interventions as a potential tool to decelerate aging processes. To test whether a life-long microbiome rejuvenation strategy could delay or even prevent aging in non-ruminant mammals, we performed recurrent fecal microbial transfer (FMT) in mice throughout life. Transfer material was either derived from 8-week-old mice (young microbiome, yMB) or from animals of the same age as the recipients (isochronic microbiome, iMB) as control. Motor coordination and strength were analyzed by rotarod and grip strength tests, intestinal barrier function by serum LAL assay, transcriptional responses by single-cell RNA sequencing, and fecal microbial community properties by 16S rRNA gene profiling and metagenomics.
Results
Colonization with yMB improved coordination and intestinal permeability compared to iMB. yMB encoded fewer pro-inflammatory factors and altered metabolic pathways favoring oxidative phosphorylation. Ecological interactions among bacteria in yMB were more antagonistic than in iMB implying more stable microbiome communities. Single-cell RNA sequencing analysis of intestinal mucosa revealed a salient shift of cellular phenotypes in the yMB group with markedly increased ATP synthesis and mitochondrial pathways as well as a decrease of age-dependent mesenchymal hallmark transcripts in enterocytes and TA cells, but reduced inflammatory signaling in macrophages.
Conclusions
Taken together, we demonstrate that life-long and repeated transfer of microbiota material from young mice improved age-related processes including coordinative ability (rotarod), intestinal permeability, and both metabolic and inflammatory profiles mainly of macrophages but also of other immune cells.
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Video Abstract
Journal Article
Attitudes and Practices Related to COVID-19 Vaccination with the Second Booster Dose among Members of Athens Medical Association: Results from a Cross-Sectional Study
by
Benetou, Vasiliki
,
Papagiannis, Dimitrios
,
Riza, Elena
in
Attitudes
,
Beliefs, opinions and attitudes
,
booster vaccine
2023
Background: There are limited data on the attitudes and acceptance of the second booster (fourth dose) of the COVID-19 vaccination among physicians. Methods: A cross-sectional, questionnaire-based, online study was conducted among members of the Athens Medical Association (A.M.A.) who were invited to participate anonymously over the period from January to March 2023. Results: From the 1224 members who participated in the survey, 53.9% did not receive the fourth dose of the COVID-19 vaccine. The main reasons for no vaccination were the lack of obligation to receive the fourth dose, the history of three doses of the COVID-19 vaccine and the lack of sufficient information about the effectiveness of the fourth dose. Over half of the three-dose-vaccinated participants were willing to receive the fourth dose in the near future. Interestingly, the vaccination coverage among participants who had been informed about the fourth dose through scientific sources was low. Conclusions: The low vaccination coverage with the fourth dose reported in this study can lead to broad and serious consequences, such as increase in COVID-19 infections, reduction of available healthcare staff and increased caseloads of COVID-19 in hospitals. Furthermore, hesitant physicians will adversely influence the vaccination uptake among the general population due to their key role in informing and recommending the vaccine. The healthcare system administration should acknowledge and address physician’s concerns through effective communication and better support.
Journal Article