Detection of diarrhea-causing Escherichia coli using DNA-probes]

To assess the role of enterovirulent Escherichia coli at home and abroad, faeces samples of patients with diarrhoea and of healthy controls in Tunisia, Seville (southern Spain) and the Netherlands were investigated. Enterovirulent E. coli were identified by hybridization with five different non-radioactively labelled DNA probes specific for enterotoxigenic E. coli (ETEC), enteropathogenic E. coli (EPEC) and verocytotoxin producing E. coli (VTEC). ETEC was the main causative agent of travellers' diarrhoea in Tunisia. The isolation of ETEC in the Netherlands was shown to be related to travel in endemic areas. EPEC probe positive strains were isolated in children and in adults, but were not in all cases associated with intestinal disease. During this study no VTEC were detected. From an immunocompromised kidney transplantation patient with sepsis and diarrhoea ETEC were isolated from blood.     

Student perceptions about the characteristics of an effective discussion during the reporting phase in problem-based learning

To explore student perceptions of factors contributing to the effectiveness of discussions in the reporting phase of the problem-based learning (PBL) process, where students report and synthesise the results of self-study. Forty-eight Year 1 and 2 medical students participated in 6 focus group interviews about the characteristics of effective group discussions and possible improvements. The data were analysed qualitatively in several stages. The analysis yielded 4 main characteristics of effective discussions: asking for, giving and receiving explanations; integrating and applying knowledge; discussing differences with regard to learning content, and guiding and monitoring the content and the group process of the discussion. Integrating and applying knowledge included structuring, relating and summarising information and providing examples from practice. Discussing different opinions included discussing a variety of literature resources and disagreements. The main learning effects mentioned by the students were retention, understanding, integration and application of knowledge. Students have clear ideas about what promotes effective discussions during the reporting phase. Their PBL experience has provided them with some insights that are in line with theory and research on collaborative learning. Future research should examine differences between student and tutor perceptions of the quality of discussions. Introductions to PBL for students and tutors should include training in asking open but focused questions, supporting explanations with arguments and dealing with conflicts about learning content. Tutors should be trained in giving effective and personal feedback. Collaborative creation of external knowledge representations (i.e. concept maps) should be advocated, as should variety of literature resources.     

Participants' opinions on the usefulness of a teaching portfolio

BACKGROUND: Whether teaching portfolios achieve their aim of stimulating teachers' professional development is favourably affected by the incorporation of a balanced structure and effective social interactions, such as coaching. We explored teachers' experiences with a teaching portfolio that was structured by teaching roles, portfolio assignments and conversation protocols. The related social interactions consisted of meetings with peers and personal coaches. Teachers' and coaches' opinions were sought about the benefits and the enabling and disabling factors of the portfolio structure and the social interactions involved. METHOD: Five teachers and their personal coaches were individually interviewed about their experiences with the portfolio. Protocols were analysed using a top-down strategy. RESULTS: The teaching roles were helpful in analysing teaching, but the assignments and the conversation protocols were too detailed and directive. The social interactions were perceived as very valuable for professional development, particularly the meetings with personal coaches. CONCLUSIONS: The portfolio structure and social interactions, especially personal coaching, appeared to be helpful for teachers in analysing their teaching practice. The assignments and protocols, however, were too detailed and directive. This may be resolved by using assignments and conversation protocols more flexibly and enabling adjustment to personal learning needs. The high appreciation of personal coaching might be related to the freedom for teachers to choose their own coach. The results can be used by portfolio designers as guidelines for how to achieve a balanced structure and effective social interactions and how these might be combined to increase the benefits of working with a portfolio to teachers.     

Portfolio as a tool to stimulate teachers' reflections

Portfolios are increasingly being used to stimulate teachers' reflections. Frameworks for reflection on teaching often emphasize competencies and behaviours. However, other aspects of teacher functioning are also important, such as the teaching environment and individual teachers' beliefs, professional identity and mission. In a study among five medical school teachers, we explored how a portfolio stimulated reflections on the various aspects of teaching functioning. Outcomes of written portfolio assignments were collected and analysed to identify examples of reflections on the various aspects of teacher functioning. Examples of reflections on all aspects of teacher functioning were found, although examples of reflections on competencies were easier to find than those on beliefs, identity and mission. This study might help teachers and their trainers and coaches to recognize different aspects of teacher functioning when discussing portfolios for professional development purposes. However, further development of assignments and other methods to stimulate reflections on beliefs, identity and mission are needed. Furthermore, apart from the content of teachers' reflections, teachers' reflection processes should be researched, as well as the effects of portfolio meetings with peers and coaches.     

Quality of student-generated learning issues in a problem-based curriculum

In a problem-based curriculum students generate learning issues that are the guidelines for their individual study. In an earlier study it was found that a useful learning issue contains a keyword that demarcates the content of a certain topic to be studied and is formulated concisely and unambiguously for all members of the tutorial group. This study investigates two questions. First, how many learning issues can be classified as being of good or bad quality as evaluated against three criteria? Second, what are examples of well and badly formulated learning issues? Learning issues were collected for two problems in the first year during two tutorial meetings of the Maastricht Medical School in the academic year 1998-99. In the next academic year, 12 first year-students were asked to judge the learning issues for each problem against three criteria. The results showed that 21% of the learning issues for one problem and 32% for the other problem were classified as scoring high on all three characteristics. A very small percentage of learning issues (5% and 2%) were classified as scoring low on all three characteristics. Most learning issues scored differently on each of the characteristics. Although most learning issues contain a keyword, many of them were formulated ambiguously and not concisely. It is concluded that first-year students are not yet able to formulate clear learning issues.     

The effect of EDTA, cations, and various buffers on the morphology of erythrocyte membranes: an electron-microscopic study

Membranes of human erythrocytes were prepared by stepwise osmotic hemolysis in Ca2+-free solutions. Examination with the electron microscope after negative staining showed some short, conelike protuberances on the surface of about 20 percent of the ghosts, while 80 percent were round, intact spheres. After Ca2+ treatment, all membranes were round and intact. After exposure to ethylenediaminetetraacetic acid (EDTA) (1.0 mM, pH 7.4), the entire ghost surface was covered with long, thin extrusions called stromalytic forms (about 460 per cell). Their sizes, shapes, and fine structure are described. Exposure to ionic calcium (1.4 times 10-minus 4M) abolished the EDTA-induced stromalytic forms. A second exposure to EDTA reversed this Ca2+ effect. ATP, like EDTA, produced stromalytic forms. EDTA- induced stromalytic forms were also abolished by Zn2+, La3+, and Nd3+ at concentrations of 1-5 times 10-minus 4 M. Mg2+ at 10-minus 2 M was ineffective. Ghosts were prepared by graded lysis in various buffers. Those prepared in phosphate were the most stable and provided consistent EDTA effects and Ca2+ reversal. Ghosts in Tris-HCl showed breakdown unless salt was added. Moderately satisfactory ghosts were also obtained in Hepes-NaOH buffer and salt.     

Clinical,laboratory and radiological features and outcomes of moderate to severe COVID-19 patients: A descriptive retrospective study

Objective: To describe the clinical, laboratory and radiological characteristics and outcomes of moderate-to-severe coronvirus disease 2019 (COVID-19) patients.Methods: We retrospectively analyzed 43 RT-PCR confirmed moderate-to-severe COVID-19 patients who were admitted to a tertiary care center. The primary composite outcomes were admission to intensive care unit, requirement of mechanical ventilation, and death. Results: The median age of the patients was 50 years, and 62.8％ of the patients were male. Out of 43 patients, 15 (34.88％) were categorized as severe. A total of 26 (60.47％) patients had 1 or more comorbidities [diabetes (34.88％) and hypertension (30.23％)]. The median duration from the onset of symptoms to admission was 3 days, and the most common symptoms were dyspnoea (90.7％), cough (79.07％), fever (69.77％), and body ache (46.51％). Leucopenia was presented in 14 (32.56％) patients, lymphopenia in 26 (60.47％) patients, and monocytosis in 7 (16.28％) patients. Besides, 40 (93.02％) patients had bilateral patchy nodular or interstitial infiltration on chest X-ray. The primary outcomes occurred in 20 patients (46.5％), among whom 8 required mechanical ventilation. The patients who had met the primary outcomes were older. They were prone to have at least 1 comorbidity (P=0.004), diabetes (P=0.01), hypertension, higher sequential organ failure assessment score, more tachycardia, lower SpO2, lower PaO2/FiO2, more thrombocytopenia, and more pancytopenia. Conclusions: This retrospective study identified several risk factors for poor outcomes in adults with COVID-19. In particular, older age, tachycardia, high SOFA score, low SpO2, low PaO2/FiO2, presence of comorbidities in form of diabetes and hypertension, thrombocytopenia, and pancytopenia at admission were associated with higher odds of ICU admission, a requirement of mechanical ventilation and in-hospital death.