Constantinos C. Frangos

Problematic Internet Use among Greek university students: an ordinal logistic regression with risk factors of negative psychological beliefs, pornographic sites, and online games.

The aim of this paper is to investigate the relationships between Problematic Internet Use (PIU) among university students in Greece and factors such as gender, age, family condition, academic performance in the last semester of their studies, enrollment in unemployment programs, amount of Internet use per week (in general and per application), additional personal habits or dependencies (number of coffees, alcoholic drinks drunk per day, taking substances, cigarettes smoked per day), and negative psychological beliefs. Data were gathered from 2,358 university students from across Greece. The prevalence of PIU was 34.7% in our sample, and PIU was significantly associated with gender, parental family status, grade of studies during the previous semester, staying or not with parents, enrollment of the student in an unemployment program, and whether the student paid a subscription to the Internet (p < 0.0001). On average, problematic Internet users use MSN, forums, YouTube, pornographic sites, chat rooms, advertisement sites, Google, Yahoo!, their e-mail, ftp, games, and blogs more than non-problematic Internet users. PIU was also associated with other potential addictive personal habits of smoking, drinking alcohol or coffee, and taking drugs. Significant risk factors for PIU were being male, enrolment in unemployment programs, presence of negative beliefs, visiting pornographic sites, and playing online games. Thus PIU is prevalent among Greek university students and attention should be given to it by health officials.

Validity of intraoperative gross examination of myometrial invasion in patients with endometrial cancer: a meta-analysis.

Objective. The current recommended endometrial cancer surgical treatment is abdominal extrafascial total hysterectomy with bilateral salpingo‐oophorectomy followed by pelvic lymphadenectomy if >50% myometrial invasion is estimated by intraoperative gross examination (IGE). This meta‐analysis aims to quantify evidence regarding the validity/predictive value of IGE staging compared with final histology. Design. Meta‐analysis of studies published until October 2011. Setting. Systematic search, according to PRISMA guidelines, of the six major medical literature databases – Medline, Scopus, EMBASE, Google Scholar, Ovid, Cochrane. Population. Sixteen eligible studies including 2567 endometrial cancer patients. Methods. Pooled sensitivity/specificity, accuracy, negative/positive predictive value (NPV/PPV) and diagnostic odds ratio (DOR) of IGE were calculated and the summary receiver operator characteristic (sROC) curve was constructed. A meta‐regression analysis was used to explore the role of potential modifiers of sensitivity and specificity. Main outcome measures. Pooled diagnostic measures of IGE indices. Results. Sixteen studies (15 retrospective, one prospective) meeting the inclusion criteria were qualitatively analyzed. Pooled IGE estimates were: sensitivity = 0.75 (95%CI: 0.72–0.78), specificity = 0.92 (95%CI 0.90–0.94), accuracy = 0.87 (95%CI 0.86–0.88), NPV = 0.89 (95%CI 0.87–0.92), PPV = 0.80 (95%CI 0.76–0.84) and DOR = 36.9 (95%CI 28.7–47.4). No significant modifiers were identified for sensitivity or specificity. Conclusions. The synthesized measures presented here for the first time showed that accuracy, sensitivity and specificity of IGE were 87, 75 and 92%, respectively, which indicates that IGE is useful for estimating depth of myometrial invasion and staging of endometrial cancer in clinical practice. The degree to which the relatively low values of some of its performance indicators could be improved remains to be elucidated in order for the values to be comparable with those from frozen section biopsies.

Spatial and temporal evaluation of cell attachment to printed polycaprolactone microfibres

Surface topography plays a crucial role in influencing cellular responses and has therefore been utilized in the development of numerous implantable devices. Whilst numerous studies have either investigated cell attachment or migration post-attachment, few have looked at the early-stages of this process temporally. The aim of this study was to evaluate the use of time-lapse microscopy to study the behaviour of fibroblasts cultured with polycaprolactone microfibres and to assess spatially and temporally the cell-structure interaction over a 24h period. Ordered polymeric structures were printed (predetermined) onto glass substrates using an electrohydrodynamic direct write process to produce fine (3-5 μm wide) structures. Fibroblast attachment and migration were characterized as a function of distance perpendicular from structures (∼17.3, 34.6 and 51.9 μm). The use of time-lapse microscopy revealed a gradual decrease in cell attachment as the distance from the microfibres was increased. The technique also revealed that some cells were attaching and detaching from the microfibre multiple times. Our findings demonstrate that time-lapse microscopy is a useful technique for evaluating early-stage cell-biomaterial interaction that is capable of recording important events that might otherwise be overlooked.

Rapid magnetic cell delivery for large tubular bioengineered constructs

Delivery of cells into tubular tissue constructs with large diameters poses significant spatial and temporal challenges. This study describes preliminary findings for a novel process for rapid and uniform seeding of cells onto the luminal surface of large tubular constructs. Fibroblasts, tagged with superparamagnetic iron oxide nanoparticles (SPION), were directed onto the luminal surface of tubular constructs by a magnetic field generated by a k4-type Halbach cylinder device. The spatial distribution of attached cells, as measured by the mean number of cells, was compared with a conventional, dynamic, rotational cell-delivery technique. Cell loading onto the constructs was measured by microscopy and magnetic resonance imaging. The different seeding techniques employed had a significant effect on the spatial distribution of the cells (p < 0.0001). The number of attached cells at defined positions within the same construct was significantly different for the dynamic rotation technique (p < 0.05). In contrast, no significant differences in the number of cells attached to the luminal surface were found between the defined positions on the construct loaded with the Halbach cylinder. The technique described overcomes limitations associated with existing cell-delivery techniques and is amenable to a variety of tubular organs where rapid loading and uniform distribution of cells for therapeutic applications are required.

Online and mobile customer behaviour: a critical evaluation of grounded theory studies

With the rapid increase in electronic and mobile commerce over the last few years, the academic literature on online and mobile customer behaviour has been fairly plentiful with a great deal of quantitative studies testing variations of existing customer behaviour theories. However, little attention has been given to qualitative studies in the field, which seek to explore new aspects of online or mobile customer behaviour, adding to existing theories or even creating new ones. Thus, the purpose of the present paper is to critically evaluate studies employing Grounded Theory (GT), a method commonly used for theory building in qualitative social research. Nine studies were identified examining online or mobile customer behaviour under this approach, providing theories based on emerging categories. Results of their studies seem to be very similar to existing customer behaviour theories, occasionally adding new categories to the existing theory nomenclature. Studies presented weaknesses regarding the accurate methodological conduct of GT and the process of generating theory, attributed predominantly to methodological, verification and reporting bias. Nevertheless, the main advantage of GT studies remains the generation of theory that can be applied in practice, reinforced by the presentation of conceptual prospects for testing new variables in quantitative studies. Overall, the contribution of GT studies to online and mobile customer behaviour research should be based on more rigorous methodology and aim to challenge rather than confirm existing theories with the purpose of advancing knowledge in the field.

George Higoumenakis (1895-1983): Greek dermatologist.

This paper describes the Higoumenakis sign, enlargement of the sternal end of the clavicle in patients with late congenital syphilis and the dermatologist after whom it is named. Several professors and doctors from the Medical School of the University of Athens opposed his actions especially at the University in Greece. His persistence led him to productive scientific activity in syphilis, leishmaniasis and psoriasis. He became a member of the Greek Parliament from 1964 to 1967 and eventually Minister of Hygiene - even though this may have been an imprudent political choice, due to the unstable sociopolitical status of that period. He died on 27 December 1983 at the age of 88.

Towards an extension of the two-variable model of carcinogenesis through oncogenes and tumour suppressor genes

Currently, carcinogenesis is considered to be the result of mal-expression of tumour suppressor genes and oncogenes, leading either way to uncontrollable and disorganized cell mitosis. Recently a novel class of genes has drawn the interest of the scientific community. These are microRNAs (miRNAs), a class of noncoding RNAs, 20-23 nucleotides in length, that can up or downregulate gene expression of downstream gene targets (including transcription factors, oncogenes, and tumour suppressor genes) at the post-transcriptional level. Some members of this new class of genes seem to have the potential to act simultaneously either as oncogenes or as tumour suppressor genes depending on the molecular microenvironment of the cell. We elaborate on this hypothesis by giving examples of miRNAs (e.g. mir-9, miR-17-92) which seem to function by the abovementioned mechanism. This could mean that the deterministic notion of carcinogenesis as a result of merely tumour suppressor genes and oncogenes deregulation could be revised to contain the fact that certain members of this novel class of genes have the potential to play both roles simultaneously.

Towards a realistic approach to medical biography

It is notable that the history of medicine was first taught through biographies, and mainly through hagiographical texts of ‘great doctors’ – often called the Oslerian approach. Charles Coulston Gillispie saw the history of ideas ‘as centred on “individual great men”, the thought of a few brilliant lights who bravely probe at the “edge of objectivity” in a quest to advance the collective scientific understanding of humanity’. 1 Medical biography praises the inspirational work of these great doctors and medical men, exemplars in their fields. The social history of medicine attempted to demonize the old-school biographically-centred approach in the history of medicine, executing quite a hit on this mentality. Nevertheless, recent texts have proposed reconsidering the significance of medical biography by medical historians since biographies are, after all, another form of microhistory, versions of which currently fill the pages of medical history journals. Biography is suggested to have significance for the history of medicine but how is it possible to give reliable descriptions of facts, a necessary facet of history, if we tend to sanitize every action of the subject? A realistic approach depicts the subject in a more human dimension, under personal or social constraints and boundaries. Before we re-accept the role of medical biography in the history of medicine, we should reflect on the definition of biography and the purpose it serves. Nye 2 explains that it maintains a great public appeal and offers historians of science an opportunity to reach a