Development and characterization of a 3D oral mucosa model as a tool for host-pathogen interactions.

The aim of this study was to (i) design, develop and validate a practical and physiologically relevant reconstituted in vitro oral mucosa tissue model and (ii) to assess its applicability in in vitro host-pathogen interactions with C. albicans and S. aureus. Co-culture organotypic constructions were created by incorporating specific numbers of keratinocytes (NOK-si) onto cellularised, collagen gel scaffolds containing human gingival fibroblasts incubated in KGM media and cultured for 14 days. The detection of the appropriate oral mucosa/epithelial structure was evaluated by histology (hematoxylin and eosin (HE), periodic acid-Schiff (P.A.S.) and Picrosirius red), and immunocytochemistry (cytokeratin 13, cytokeratin 14, Ki-67 and collagen IV) compared to a normal human gingiva. The morphology of the reconstituted tissue was analyzed by Transmission Electron Microscopy. To further quantitate tissue damage, lactate dehydrogenase (LDH) was measured in the tissue supernatant. NOK-si grown upon a gingival scaffold provided an organotypic model in an in vitro setting and exhibited structural characteristics typically associated with normal oral mucosa. Immunocytochemistry revealed the detection of epithelial cytokeratins 13 and 14, Col IV and Ki-67 in the reconstituted oral mucosa model. Infection was detected after 8 h and 16 h. This study presents an in vitro cellularised, organotypic model of reconstituted oral mucosa, which enables close control and characterization of its structure and differentiation over a mid-length period of time in culture.

When another assessment attempt is bad for progress.

This article was migrated. The article was marked as recommended. The history and current practice of resit tests are briefly reviewed. The evidence supporting resits and also the problems associated with resits are evaluated. In addition, the financial implications of resits for both students and institutions are explored, along with the need to ensure assessments establish currency of ability and are a reflection of the long-term capability of students. Although resit outcomes are typically capped at the passing score we argue that they still afford an unfair advantage. We conclude that where resit opportunities are provided then they should have higher pass marks than first sit attempts. However, we recommend that the stress of high stakes exams, and thus resits, should be avoided. Consequently, a case is made for an alternative to resits whereby multiple lower stakes assessment results are aggregated.

Angoff anchor statements: setting a flawed gold standard?

This article was migrated. The article was marked as recommended. The Angoff standard setting method depends fundamentally on the conceptualisation of an anchor statement. The precise wording and consequent interpretation of anchor statements varies in practice. Emphasis is often placed on standard setting judges' perceptions of difficulty for a candidate subgroup. The current review focusses on the meaning of anchor statements and argues that when determining the required standard of performance it is more appropriate to consider: (1) what it is important to achieve, and not how difficult it is to achieve it; (2) what all candidates should achieve, and not what a subgroup of candidates would achieve. In summary, current practice should be refined by using an anchor statement which refers to estimating the 'minimum acceptable performance by every candidate' for each item being tested, and then requiring each judge to score the relevant aspects of importance which could then be combined to derive a cut-score.

Making progression and award decisions.

This article was migrated. The article was marked as recommended. It is incumbent on medical schools to show, both to regulatory bodies and to the public at large, that their graduating students are "fit for purpose" as doctors. Since students graduate by virtue of passing assessments, it is vital that schools quality assure their assessment procedures, standards and outcomes. An important part of this quality assurance process is how progression and award decisions are made. This begins with developing clear evidence-based policies and processes that ensure assessments are effective, relevant, fair, robust and secure. Assessment is a series of processes primarily designed to enable judgements to be made as to whether a student has, or has not, met the standard required for the outcomes at that stage. This article will provide a clear rationale and guidance for establishing robust processes for making progression and award decisions.