The difficult patient: creation of a curriculum by third-year family practice residents.

BACKGROUND AND OBJECTIVES: Family practice residents tend to perceive psychosocial problems as less important than other factual aspects of their curriculum. To address this, we developed a problem-based learning (PBL) approach to the biopsychosocial model of medical care. METHODS: Third-year residents presented current problematic patients at a PBL advanced psychiatry conference. Data were collected on topics generated, resident attendance, and conference evaluation. RESULTS: The residents generated a topic list that closely matched a prior faculty-generated list. Some topics were discussed on multiple occasions; others not on the faculty list were also generated. Topics omitted were mental health in the physician's home, crisis prevention/intervention, and troubled marriages. In 1992-1995, resident attendance ranged from 56%-79%. A minority (0-5 residents) consistently attended fewer than 50% of the conferences. Residents evaluated the conference from "good" to "very good." CONCLUSIONS: By employing a PBL format and allowing residents to present current patients, conferences were better attended and covered almost all topics previously identified as important. PBL promoted efficient use of residents' time since residents were only required to research the literature about group knowledge deficits. This provided good training for the residents and excellent continuing medical education for faculty.

The consistency of students' self-assessments in short-essay subject matter examinations.

This longitudinal study compares the accuracy of self-assessments of 22 students across four examinations during their first 2 years of medical school. The four examinations used a similar short-essay format and covered many of the same basic science disciplines at similar levels of difficulty. Immediately after answering an average of 20 questions on each examination, students predicted their performance on those questions. After assigned subject matter experts had scored the questions, the differences between students' predictions and the experts' scores were calculated for each question. The degree to which students had over- and underestimated their performance across all questions was determined by separately averaging all positive and negative differences between students' and experts' assessments on each examination. The results of the study indicated that accuracy in self-assessment improved from examination 1 to examination 3 (with less overestimation) and dropped on examination 4 (with more underestimation). The results revealed no relationship between self-assessment estimations and actual scores received. Furthermore, the self-assessment estimations tended to be statistically correlated between contiguous examinations (i.e., examinations 1 and 2, 2 and 3, etc.) but not between non-contiguous ones (i.e., examinations 1 and 3, etc.). The results of the study are interpreted to suggest that the students in the study have a self-assessment tendency towards over- or underestimation that is somewhat stable but that gradually evolves over time with experience, maturity and self-assessment practice. The most frequent direction of change is towards decreased overestimation and increased underestimation. These results are consistent with the findings of other recent longitudinal self-assessment studies.

Scoring the objective structured clinical examination using a microcomputer.

The objective structured clinical examination (OSCE) is being used increasingly to assess students' clinical competence in a variety of controlled settings. The OSCE consists of multiple stations composed of a variety of clinically relevant problems (e.g. examining simulated patients, diagnosing X-rays, etc.) Generally, three types of performance data are collected: answers to multiple choice or true/false questions, written short answers, and performance check-lists completed by observers. In most OSCEs these student performance measures are scored by hand. This is time-consuming, increases the probability of mistakes and reduces the amount of data available for analysis. This paper describes a method of computer scoring OSCEs with over 100 students using statistical and test-scoring software regularly used for multiple choice examinations. During the examination, students, markers and raters code answers and performance data directly on optical mark-sheets which are read into the computer using an optical mark reader. The resultant computer data can be efficiently scored and rescored, grouped into different types of subscales, weighted to reflect questions' relative importance, and easily printed in a variety of report formats.

Is it worth it? A look at the costs and benefits of an OSCE for second-year medical students.

For the past two years, the Bowman Gray School of Medicine has used an Objective Structured Clinical Exam (OSCE) to measure the performance of 117 first- and second-year medical students at the end of introductory courses on differential and physical diagnosis. Given the surprisingly high costs of conducting the OSCE ($1300 for supplies and 527 person-hours of donated time), data about the format's perceived benefits were collected. All of the faculty involved in the examination who responded to a questionnaire (80%) reported that it was worth the time they had volunteered to evaluate students by observation and that the format should be used in the future. The majority of student examinees also reported that the OSCE format was appropriate for the course and should continue to be used.

Amplified lymphokine production phenomenon confirmed by a macrophage 2-D-[3H]deoxyglucose transport assay.

The amplified lymphokine production phenomenon was confirmed by using an improved macrophage 2-d-[(3)H]deoxyglucose uptake assay as an indicator of lymphokine activity. Amplified lymphokine titers were determined in supernatants derived from tuberculin-sensitive, antigen (purified protein derivative)-stimulated, guinea pig peritoneal exudate and spleen cell suspensions after the cells were allowed to sediment into a pellicle in a conical culture tube. The deoxyglucose uptake assay, which probably measured an effect on the macrophage cell membrane, was easy to perform, and the prozone phenomenon observed with other lymphokine assay systems did not occur. The deoxyglucose uptake-enhancing moiety was stable at 56 degrees C for 1 h and had a molecular weight of between 50,000 and 100,000, as defined by Amicon ultrafiltration. Exposure of macrophages to the lymphokine-containing supernatants did not increase macrophage deoxyglucose uptake significantly until after 9 h of incubation had elapsed. The effect on deoxyglucose uptake was to increase the V(max) without changing the K(m) value. Deoxyglucose uptake also involved a stereospecific carrier-facilitated transport system both in the presence and in the absence of lymphokine. The increased deoxyglucose transport induced by the lymphokine-containing supernatants was reversible. A migration inhibitory factor activity of similar molecular weight and heat stability was also present in these supernatants, but in titers lower than the titers of the deoxyglucose uptake-enhancing activity. Consequently, in the absence of a complete biochemical characterization, the two effects cannot be ascribed to the same molecular species at this time. Such a characterization, along with studies of lymphokine production and action, should be facilitated greatly by the availability of very high-titer supernatants derived by this geometric culture method.

A lymphokine resembling transfer factor that stimulates MIF production by nonsensitive lymphocytes.

High potency preparations of a new heat-labile, low m.w. (less than 5000) lymphokine (LMWL) were obtained by culturing tuberculin-sensitive guinea pig peritoneal exudate cells (PEC) with PPD in geometric conditions that promote amplified lymphokine production. This LMWL has the ability, in the presence of PPD, to stimulate nonsensitive PEC to produce a heat-stable molecule(s) resembling MIF with a m.w. in the range 50,000 to 100,000. The effects of the LMWL (less than 5000 daltons) and the MIF-like molecule(s) (50,000 to 100,000 daltons) were defined by the indirect macrophage migration assay and a macrophage deoxyglucose uptake assay. It is possible that LMWL represents a form of transfer factor with the ability to recruit unsensitized lymphocytes to produce MIF.

Amplified migration inhibition effect.

When tuberculin-sensitive peritoneal exudate cells are incubated in a culture flask with tuberculin purified protein derivative, macrophage inhibition factor and other lymphokines are released into the culture medium. We have described how, if incubation is carried out in a stationary conical culture tube, intercellular contact between the peritoneal exudate cells is facilitated as the cells sediment into a pellicle at the bottom of the tube. This results in augmented release of inhibitory lymphokines into the supernatant culture medium with titers up to 10(9) times greater than those obtained by conventional culture methods using a flatbottomed culture dish or flask. When such high-titered inhibitory supernatants were subjected to fractionation by sequential Amicon ultrafiltration, two clearly distinct macrophage-inhibitory lymphokines were found. The first was present, after fractionation, in a titer of 10(12), had a molecular weight in the range of 50,000 to 100,000, and was heat stable at 56 degrees C for 1 h. This moiety is probably identical to guinea pig macrophage inhibition factor. Unexpectedly, a second heat-labile inhibitory substance with a molecular weight between 500 and 1,000 was found in a titer of 10(4) after fractionation. This low-molecular-weight, heat-labile material may represent a new lymphokine with a direct inhibitory action on macrophage migration. Theoretically, the data are also consistent with the possibility that it could act as a chemical immunotransmitter which stimulates amplified production of macrophage inhibition factor by lymphocytes within the cell pellicle and leads indirectly to inhibition of macrophage migration.

The defense of the lung: studies of the role of cell-mediated immunity.

The defense of the lung against infections, toxins and allergens is accomplished by an excretory transport mechanism and by the interaction of cellular and humoral defense systems. Pulmonary alveolar macrophages represent a common effector pathway for both nonspecific cellular phagocytic defenses and for specifically triggered cell-mediated immunity, via T lymphocytes. Nonspecific activation of macrophages is induced by toxic substances. Studies of the immunocytologic system indicate partial compartmentalization and "local" immunity for both cellular and humoral systems. Further studies on pulmonary cell-mediated immunity have characterized an amplification mechanism by which antigen-induced stimulation of T lymphocytes leads to recruitment of nonsensitive lymphocytes through the production of a low-molecular weight "transfer factor." Other lymphocyte-produced mediators (lymphokines) act to attract, aggregate and accumulate macrophages in areas of inflammation. In addition, macrophages are "activated" and show enhanced microbicidal capabilities as well as enhanced resistance to the cytotoxic effects of certain ingested microorganisms. It is postulated that cellular (nonspecific) and cell-mediated (specific) immune defenses play important roles in protection against several categories of microorganisms in a hierarchy of virulence.

Amplified migration inhibition effect.

Upon exposure to specific antigen in tissue culture, sensitive lymphocytes released macrophage migration inhibition factor and other lymphokines into the supernatant culture medium. Migration of peritoneal macrophages from nonsensitive animals was inhibited in the presence of such supernatants. However, with previous techniques it was found that an inhibitory effect was present at only low low titers (less than 10(2)). It is therfore of great interest that by increasing cellular density, the total number of cells being kept constant, inhibitory activity can be amplified by a factor as great as 10(10). This amplification was observed only when lymphocytes and macrophages were loosely packed, as by spontaneous sedimentation in a conical test tube. The effect was abolished by dispersing the cell suspension in a flat-bottomed flask or, alternatively, by shaking the test tube so that intimate prolonged intercellular contact was prevented.

Bacterial endocarditis. Echocardiographic and clinical evaluation during therapy.

In two patients with bacterial endocarditis and apparent vegetations, the echocardiographic findings included thickening but normal excursion of the mitral leaflet and abnormal shaggy echoes superimposed on the mitral leaflet echogram. Both patients had had endocarditis several weeks before the study was performed. In both patients the abnormal echoes disappeared after antibiotic therapy. Whether or not the echocardiographic findings are specific to bacterial endocarditis must be determined by further studies. One patient had evidence of "immune complex disease" with vasculitis, hypocomplementemia, and renal failure which persisted for weeks after disappearance of vegetations on the echocardiogram. This sequence was unexpected, as a continued source of antigen for this reaction was not apparent.

Secondary respiratory infection in hospital patients: effect of antimicrobial agents and environment.

A prospective study of 358 medical and 234 postoperative patients with clinical evidence of secondary chest infection showed that previous administration of antimicrobial agents greatly reduced the chance of obtaining a clear-cut laboratory report. In patients with radiographical evidence of pneumonia this led to a fourfold decrease in the overall rate of isolation of potential pathogens. Furthermore, 81 diverse "coliforms" were isolated from 258 medical and surgical patients who had received previous antimicrobial therapy while only four coliforms (all Escherichia coli) were isolated from 334 untreated patients. Thus the general hospital environment on its own seemed to have a negligible influence in promoting the growth of coliform flora in sputum. Any unique effect of underlying disease in this regard was masked by that of previous therapy. Finally, the results raised the possibility that previous antimicrobial therapy might have increased the risk of secondary pneumonia in hospital patients.

Amplification of migratory inhibition factor production during the first 48 hours of exposure to antigen.

When lymphocyte-macrophage suspensions from sensitized animals are preincubated with specific antigen for 24 or more h, the following results are observed. (i) In a standard capillary macrophage migration test, there is complete inhibition of migration. (ii) When the preincubated cell suspension is mixed in varying proportions with a similar suspension from nonsensitized animals and a macrophage migration test is performed, there is no linear relationship between the degree of inhibition of migration and the proportion of sensitized lymphocytes initially present. Inhibition thus appears to be an "all-or-none" effect. (iii) In spite of the second observation, increasing periods of preincubation with antigen result in increasing inhibition. (iv) These results suggest the existence of a complex amplifying mechanism operating within the early period of exposure to antigen. (v) To test the possibility that cell proliferation contributes to this amplification, cells from sensitized guinea pigs were irradiated with a dose of 1,000 rads prior to preincubation with antigen. Despite this dose, which virtually abolishes cell division in other systems, no diminution whatever in the amplification of inhibition was observed. These results suggest the existence of an early phase of increased production of migratory inhibition factor that is not dependent on cell division but that may be related to "recruitment" of nonsensitized lymphocytes.