The effect of gender interactions on students' physical examination ratings in objective structured clinical examination stations.

PURPOSE: Previous studies have reached a variety of conclusions regarding the effect of gender on performance in objective structured clinical examinations (OSCEs). Most measured the effect on students' overall OSCE score. The authors of this study evaluated the effect of gender on the scores of specific physical examination OSCE stations, both "gender-sensitive" and "gender-neutral." METHOD: In 2008, the authors collected scores for 138 second-year medical students at the University of Calgary who underwent a seven-station OSCE. Two stations--precordial and respiratory exams--were considered gender-sensitive. Multiple linear regression was used to explore the effect of students', standardized patients' (SPs'), and raters' genders on the students' scores. RESULTS: All 138 students (69 female) completed the OSCE and were included in the analyses. The mean scores (SD) for the two stations involving examination of the chest were higher for female than for male students (83.2% [15.5] versus 78.3% [15.8], respectively, d = 0.3, P = .009). There was a significant interaction between student and SP gender (P = .02). In the stratified analysis, female students were rated significantly higher than male students at stations with female SPs (85.4% [15.5] versus 76.6% [16.5], d = 0.6, P = .004) but not at stations with male SPs (80.2% [15.0] versus 80.0% [15.0], P = 1.0). CONCLUSION: These results suggest student and SP genders interact to affect OSCE scores at stations that require examination of the chest. Further investigations are warranted to ensure that the OSCE is an equal experience for all students.

Characterization of PgPepO, a bacterial homologue of endothelin-converting enzyme-1.

PgPepO is a homologue of endothelin-converting enzyme-1 (ECE-1), with which it shares 31% identity. PgPepO was isolated from the periodontal pathogen Porphyromonas gingivalis. Recent studies have suggested a link between periodontal and cardiovascular disease, and several groups have suggested that bacterial and viral infections may contribute to the latter. P. gingivalis possesses the ability to invade, and multiply within, aortic endothelial cells and has been localized to atherosclerotic plaques. PgPepO was expressed and purified to homogeneity and we have begun detailed functional analysis, in terms of substrate preference and inhibitor specificity, in order to provide active-site comparisons with other members of the neprilysin (NEP)/ECE family. PgPepO possesses similar substrate specificity to ECE-1 and has been shown to cleave big endothelin-1 (big ET-1), big ET-2 and big ET-3, converting the substrates into their respective mature endothelin peptides. Substance P, angiotensin I, angiotensin II and neurotensin are all cleaved at multiple sites by PgPepO and the kinetics of these reactions have been compared. The potent vasoconstrictor urotensin II is not hydrolysed by PgPepO. Cleavage of bradykinin by PgPepO occurs at the Pro(7)-Phe(8) bond and is inhibited by the NEP and ECE-1 inhibitor phosphoramidon in a pH-dependent fashion (IC(50) =10 microM at pH 7.0) but not by thiorphan, an NEP-specific inhibitor. PgPepO activity is completely inhibited by EDTA. Characterization of this enzyme is important in elucidating possible links between periodontal pathogens and cardiovascular disorders such as atherosclerosis, and provides an opportunity to gain structural information on a bacterial protein with striking similarity to human ECE-1.

Beta-amyloid catabolism: roles for neprilysin (NEP) and other metallopeptidases?

The steady-state level of amyloid beta-peptide (Abeta) represents a balance between its biosynthesis from the amyloid precursor protein (APP) through the action of the beta- and gamma-secretases and its catabolism by a variety of proteolytic enzymes. Recent attention has focused on members of the neprilysin (NEP) family of zinc metalloproteinases in amyloid metabolism. NEP itself degrades both Abeta(1-40) and Abeta(1-42) in vitro and in vivo, and this metabolism is prevented by NEP inhibitors. Other NEP family members, for example endothelin-converting enzyme, may contribute to amyloid catabolism and may also play a role in neuroprotection. Another metalloproteinase, insulysin (insulin-degrading enzyme) has also been advocated as an amyloid-degrading enzyme and may contribute more generally to metabolism of amyloid-forming peptides. Other candidate enzymes proposed include angiotensin-converting enzyme, some matrix metalloproteinases, plasmin and, indirectly, thimet oligopeptidase (endopeptidase-24.15). This review critically evaluates the evidence relating to proteinases implicated in amyloid catabolism. Therapeutic strategies aimed at promoting A,beta degradation may provide a novel approach to the therapy of Alzheimer's disease.