Is an Angoff standard an indication of minimal competence of examinees or of judges?

BACKGROUND: To establish credible, defensible and acceptable passing scores for written tests is a challenge for health profession educators. Angoff procedures are often used to establish pass/fail decisions for written and performance tests. In an Angoff procedure judges' expertise and professional skills are assumed to influence their ratings of the items during standard-setting. The purpose of this study was to investigate the impact of judges' item-related knowledge on their judgement of the difficulty of items, and second, to determine the stability of differences between judges. METHOD: Thirteen judges were presented with two sets of 60 items on different occasions. They were asked to not only judge the difficulty of the items but also to answer them, without the benefit of the answer key. For each of the 120 items an Angoff estimate and an item score were obtained. The relationship between the Angoff estimate and the item score was examined by applying a regression analysis to the 60 items (Angoff estimate, score) for each judge at each occasion. RESULTS AND CONCLUSIONS: This study shows that in standard-setting the individual judgement of the individual item is not only a reflection of the difficulty of the item but also of the inherent stringency of the judge and his/her subject-related knowledge. Considerable variation between judges in their stringency was found, and Angoff estimates were significantly affected by a judge knowing or not knowing the answer to the item. These findings stress the importance of a careful selection process of the Angoff judges when making pass/fail decisions in health professions education. They imply that judges should be selected who are not only capable of conceptualising the 'minimally competent student', but who would also be capable of answering all the items.

Do short cases elicit different thinking processes than factual knowledge questions do?

PURPOSE: To assess whether case-based questions elicit different thinking processes from factual knowledge-based questions. METHOD: 20 general practitioners (GPs) and 20 students solved case-based questions and matched factual knowledge-based questions while thinking aloud. Verbatim protocols were analysed. Five indicators were defined: extent of protocols; immediate responses; re-reading of information given in the stem or case after the question had been read; order of re-reading information, and type of consideration, i.e. 'true-false' type or 'vector', that is, a deliberation which has a magnitude and a direction. RESULTS: Cases elicited longer protocols than factual knowledge questions. Students re-read more given information than GPs. GPs gave an immediate response on twice as many occasions as students. GPs re-ordered the case information, whereas students re-read the information in the order it was presented. This ordering difference was not found in the factual knowledge questions. Factual knowledge questions mainly led to 'true-false' considerations, whereas cases elicited mainly 'vector' considerations. CONCLUSION: Short case-based questions lead to thinking processes which represent problem-solving ability better than those elicited by factual knowledge questions.

Interleukin-1beta and interferon-gamma differentially regulate release of monocyte chemotactic protein-1 and interleukin-8 by human bronchial epithelial cells.

Airway inflammation is characterized by an accumulation of activated leukocytes. Bronchial epithelial cells may contribute to this process by releasing chemokines and by expressing surface membrane molecules involved in the adhesion and activation of the recruited leukocytes. In this study, we analyzed the effects of cytokines and glucocorticoids on the release of monocyte chemotactic protein-1 (MCP-1), a potent chemoattractant for predominantly monocytes and lymphocytes, by human bronchial epithelial cells and compared this with the release of interleukin-8 (IL-8), which potently attracts neutrophils. In addition, we analyzed the effects of cytokines and glucocorticoids on the epithelial expression of intercellular adhesion molecule (ICAM)-1, CD40, and human leukocyte antigen (HLA) class II molecules. Primary cultures of human bronchial epithelial cells constitutively released MCP-1 and IL-8. IFN-gamma greatly increased MCP-1 release, which was accompanied by increased expression of MCP-1 mRNA and an increased monocyte chemotactic potential. In contrast, IFN-gamma had no effect on the release of IL-8, but it did increase the epithelial expression of ICAM-1, CD40, and HLA class II molecules. IL-1beta increased both MCP-1 and IL-8 release, and increased the expression of ICAM-1 and CD40, but not HLA class II molecules. Dexamethasone partially inhibited the cytokine-induced release of MCP-1 and IL-8 and the expression of ICAM-1, CD40, and HLA class II molecules by human bronchial epithelial cells. Our results indicate that IFN-gamma and IL-1beta differentially regulate the MCP-1 and IL-8 release by human bronchial epithelial cells. In addition, IL-1beta and particularly IFN-gamma increase the expression of ICAM-1, HLA class II and/or CD40 molecules, which are involved in the adhesion and possibly activation of the recruited leukocytes. Finally, the beneficial effect of glucocorticoid therapy in airway inflammatory diseases may be mediated in part by inhibition of chemokine release and ICAM-1, CD40, and HLA class II expression by bronchial epithelial cells.

Glucocorticoid receptor expression in human bronchial epithelial cells: effects of smoking and COPD.

Previously, we found that inflammatory mediators modulated the number and binding affinity of glucocorticoid receptors (GR) in human bronchial epithelial cell lines. In this study we investigated whether smoking and chronic obstructive pulmonary disease (COPD), both characterized by airway inflammation with increased levels of inflammatory mediators, affect GR characteristics in cultured human bronchial epithelial cells (HBEC). A statistically significant difference was found between the dissociation constant (Kd) values in HBEC from smoking (Kd = 0.98+/-0.08 nM; n = 6) and nonsmoking controls (Kd = 0.76+/-0.10 nM, P = 0.03; n = 5), but no significant difference was found between the mean number of binding sites. Our results are the first indication that cultured HBEC from smokers possess GR with a lower binding affinity. This may result from the inflammation found in the airways from smokers. Furthermore, these results provide further evidence that the bronchial epithelium may be an actual target for inhaled glucocorticoid therapy.

Modulation of glucocorticoid receptor expression in human bronchial epithelial cell lines by IL-1 beta, TNF-alpha and LPS.

Bronchial epithelium plays a major role in the regulation of inflammatory reactions in the airways. It is thought to be a possible target for glucocorticoid therapy. Glucocorticoid responsiveness requires the presence of specific glucocorticoid receptors (GR). Until now, little was known about the presence of such receptors in the human bronchial epithelium. In this study we demonstrated the expression of GR messenger ribonucleic acid (mRNA) in two simian virus (SV)-40/adenovirus-transformed human bronchial epithelial cell lines, BEAS S6 and BEAS 2B. In a whole cell dexamethasone binding assay, BEAS S6 and BEAS 2B cells were found to possess (mean +/- SEM) 28.9 +/- 4.4 x 10(3) and 32.1 +/- 5.7 x 10(3) binding sites per cell, respectively, with dissociation constant (Kd) values of 8.2 +/- 1.5 and 8.6 +/- 2.4 nM, respectively. Using electrophoretic mobility shift assays we demonstrated the binding of nuclear translocated GR to specific sites on deoxyribonucleic acid (DNA), named glucocorticoid responsive elements (GRE). Lipopolysaccharide (LPS) and interleukin-1 beta (IL-1 beta) significantly increased the number of GR per cell (median = 312% and 171% of control, respectively; p < 0.05), but significantly reduced the ligand affinity of these receptors, i.e. increased the Kd (median = 410% and 145% of control, respectively; p < 0.05) in BEAS 2B cells. These results indicate that the bronchial epithelium may be an actual target for glucocorticoid therapy. Inflammatory mediators, such as IL-1 beta and LPS, modulate the number and ligand affinity of these GR. Therefore, the response of bronchial epithelium to glucocorticoid therapy may be modulated by airway diseases associated with inflammation.

Expression of lipocortins in human bronchial epithelial cells: effects of IL-1beta , TNF-alpha, LPS and dexamethasone.

In this study, we investigated the expression of lipocortin I and II (annexin I and I in the human bronchial epithelium, both in vivo and in vitro. A clear expression of lipocortin I and II protein was found in the epithelium in sections of bronchial tissue. In cultured human bronchial epithelial cells we demonstrated the expression of lipocortin I and II mRNA and protein using Northern blotting, FACScan analysis and ELISA. No induction of lipocortin I or II mRNA or protein was observed after incubation with dexamethasone. Stimulation of bronchial epithelial cells with IL-1beta, TNF-alpha or LPS for 24 h did not affect the lipocortin I or II mRNA or protein expression, although PGE(2) and 6-keto-PGF(1alpha) production was significantly increased. This IL-1beta- and LPS-mediated increase in eicosanoids could be reduced by dexamethasone, but was not accompanied by an increase in lipocortin I or II expression. In human bronchial epithelial cells this particular glucocorticoid action is not mediated through lipocortin I or II induction.

Feasibility of in situ hybridisation with chromosome specific DNA probes on paraffin wax embedded tissue.

The feasibility was studied of in situ hybridisation using chromosome specific DNA probes on paraffin wax embedded normal and malignant tissues from different organs. Both isolated nuclei and 5 microns sections were used in in situ hybridisation experiments with biotinylated repetitive DNA probes specific for the centromeric regions of chromosomes 1 and 17. The hybridisation results were visualised with peroxidase-diaminobenzidine. The optimal pretreatments with sodium thiocyanate and pepsin were experimentally defined for the different tissues. Although interphase cytogenetics on paraffin wax embedded tissue is possible, the results indicate that it has its limitations, compared with investigations on fresh tumour tissue.