Jack Rosenfeld

An admissions OSCE: the multiple mini‐interview

Context  Although health sciences programmes continue to value non‐cognitive variables such as interpersonal skills and professionalism, it is not clear that current admissions tools like the personal interview are capable of assessing ability in these domains. Hypothesising that many of the problems with the personal interview might be explained, at least in part, by it being yet another measurement tool that is plagued by context specificity, we have attempted to develop a multiple sample approach to the personal interview.

Predictive validity of the multiple mini-interview for selecting medical trainees.

Introduction  In this paper we report on further tests of the validity of the multiple mini‐interview (MMI) selection process, comparing MMI scores with those achieved on a national high‐stakes clinical skills examination. We also continue to explore the stability of candidate performance and the extent to which so‐called ‘cognitive’ and ‘non‐cognitive’ qualities should be deemed independent of one another.

The ability of the multiple mini-interview to predict preclerkship performance in medical school.

Problem Statement and Background. One of the greatest challenges continuing to face medical educators is the development of an admissions protocol that provides valid information pertaining to the noncognitive qualities candidates possess. An innovative protocol, the Multiple Mini-Interview, has recently been shown to be feasible, acceptable, and reliable. This article presents a first assessment of the techniques validity. Method. Forty five candidates to the Undergraduate MD program at McMaster University participated in an MMI in Spring 2002 and enrolled in the program the following autumn. Performance on this tool and on the traditional protocol was compared to performance on preclerkship evaluation exercises. Results. The MMI was the best predictor of objective structured clinical examination performance and grade point average was the most consistent predictor of performance on multiple-choice question examinations of medical knowledge. Conclusions. While further validity testing is required, the MMI appears better able to predict preclerkship performance relative to traditional tools designed to assess the noncognitive qualities of applicants.

Multiple mini‐interviews predict clerkship and licensing examination performance

Objective  The Multiple Mini‐Interview (MMI) has previously been shown to have a positive correlation with early medical school performance. Data have matured to allow comparison with clerkship evaluations and national licensing examinations.

Benzyl isothiocyanate is the chief or sole anthelmintic in papaya seed extracts

Papaya (Carica papaya) seeds were extracted in an aqueous buffer or in organic solvents, fractionated by chromatography on silica and aliquots tested for anthelmintic activity by viability assays using Caenorhabditis elegans. For all preparations and fractions tested, anthelmintic activity and benzyl isothiocyanate content correlated positively. Aqueous extracts prepared from heat-treated seeds had no anthelmintic activity or benzyl isothiocyanate content although both appeared when these extracts were incubated with a myrosinase-containing fraction prepared from papaya seeds. A 10 h incubation of crude seed extracts at room temperature led to a decrease in anthelmintic activity and fractionated samples showed a lower benzyl isothiocyanate content relative to non-incubated controls. Benzyl thiocyanate, benzyl cyanide, and benzonitrile were not detected in any preparations and cyanogenic glucosides. which were present, could not account for the anthelmintic activity detected. Thus, our results are best explained if benzyl isothiocyanate is the predominant or sole anthelmintic agent in papaya seed extracts regardless of how seeds are extracted.

The relationship between interviewers' characteristics and ratings assigned during a multiple mini-interview.

Purpose. To assess the consistency of ratings assigned by health sciences faculty members relative to community members during an innovative admissions protocol called the Multiple Mini-Interview (MMI). Method. A nine-station MMI was created and 54 candidates to an undergraduate MD program participated in the exercise in Spring 2003. Three stations were staffed with a pair of faculty members, three with a pair of community members, and three with one member of each group. Raters completed a four-item evaluation form. All participants completed post-MMI questionnaires. Generalizability Theory was used to examine the consistency of the ratings provided within each of these three subgroups. Results. The overall test reliability was found to be .78 and a Decision Study suggested that admissions committees should distribute their resources by increasing the number of interviews to which candidates are exposed rather than increasing the number of interviewers within each interview. Divergence of ratings was greater within the pairing of community member to faculty member and least for pairings of community members. Participants responded positively to the MMI. Conclusion. The MMI provides a reliable protocol for assessing the personal qualities of candidates by accounting for context specificity with a multiple sampling approach. Increasing the heterogeneity of interviewers may increase the heterogeneity of the accepted group of candidates. Further work will determine the extent to which different groups of raters provide equally valid (albeit different) judgments.

Solid-phase analytical derivatization: enhancement of sensitivity and selectivity of analysis

Analytical derivatizations enhance the sensitivity and selectivity of determinations for organic compounds. Classical techniques are often based on solution chemistry. Most modern sample preparation techniques, however, are based on solid-phase extractions. Solid-phase analytical derivatization bridges this gap and facilitates sample preparation by combining the isolation step with the derivatization. The solid-phase retains both reagents and derivatized analytes and often permits facile separation of excess reagent or selective elution of the desired products. The most recent solid-phase extraction techniques have been used in conjunction with analytical derivatization to automate the analysis. In this review, analytical derivatizations are presented as functional group analysis.

Derivatization in the current practice of analytical chemistry

A case is presented that analytical derivatization merits consideration in the development of modern analyses. The review demonstrates that there is sufficient data in the current literature to support such a contention. Whether using high-technology instrumentation or immunological methods that are also inherently specific and highly sensitive, investment of time and reagents pays off in higher sensitivity and improved structural information. Moreover, considerable development of automation in methods that employ analytical derivatizations has begun to answer concerns about cost-effective use of these reactions. However, the literature also cautions that such desired outcomes need to account for the complexity of the factors controlling the reaction rates for different molecules and the possibility of artefacts associated with oxygen. In biomedical analyses, there is also a particular need to take cognizance of the biochemistry involved in the formation of the analytes.

The sex-related differences in aspirin pharmacokinetics in rabbits and man and its relationship to antiplatelet effects

There are a number of reports which suggest that the antithrombotic effect of aspirin is limited to males. It is unclear whether this effect is due to sex-related differences in the effect of aspirin on platelets, the vessel wall, or the pharmacokinetics of aspirin. To test these possibilities we examined the sex-related differences in (1) vessel wall PGI2 release and its inhibition by and recovery from aspirin in rabbits; (2) the effects of aspirin on platelet aggregation, thromboxane B2 and beta-thromboglobulin (BTG) release in man, and (3) the pharmacokinetic characteristics of aspirin, in both rabbits and man. Vascular wall PGI2 measured as 6-keto-PGF1 alpha, was not different in male and females rabbits, and was inhibited to a similar extent by identical concentrations of aspirin. The duration of this inhibitory effect was also the same in males and females. The pattern of inhibition of collagen-induced platelet aggregation, and collagen-induced thromboxane B2 and BTG release by aspirin were not different in either sex. There was, however, a sex-related difference in a number of pharmacokinetic characteristics of aspirin both in rabbits and man. Thus, aspirin was absorbed more rapidly, distributed in larger apparent volume and was hydrolysed more rapidly in females. These observations suggest that the sex-related differences in the antithrombotic effects of aspirin seen in clinical studies are not due to differences in the effects of aspirin on the inhibition of platelet function mediated by the inhibition of cyclo-oxygenase in either the platelet or the vessel wall. An effect of aspirin on platelet function independent of the inhibition of cyclo-oxygenase has been described and it is possible that this effect may be influenced by sex-related differences in the pharmacokinetics of aspirin.

Solid-phase sample preparation of natural waters with reversed-phase disks

Abstract An investigation of sample preparation for natural waters using the Empore disk was conducted. The Empore disk is a new solid-phase sample preparation technology which was developed for rapid isolation of organic contaminants from aqueous matrix. In order to increase the volume of water that could be prepared, it was found that in-line or off-line filtration prior to the extraction step was required. The appropriate filters were identified. When more than 10 liters of natural water were analyzed a non-specific interference to capillary gas chromatography-electron-capture detection determination of analytes was present. The use of the Empore disks offered some advantages in ease and specificity of elution that was not available with solvent extraction and other solid-phase sample preparation technologies.