Impacting faculty teaching and student performance: nine years' experience with the Objective Structured Clinical Examination.

BACKGROUND: The impetus for administering the 2nd-year Objective Structured Clinical Examination (OSCE) came from the great variability in student performance observed by 3rd-year clerkship directors. PURPOSE: To document the effects of the OSCE on faculty teaching, student performance, and the curriculum over 9 years of administration of the examinations to more than 1,000 second-year medical students. METHOD: A 20-station OSCE was administered to all medical students at the end of their 2nd year. Using predetermined criteria, clinical faculty served as evaluators in each station. A mix of 1st-, 3rd-, and 4th-year medical students were recruited to serve as simulated patients. Faculty evaluators and examinees completed a questionnaire evaluating their experience with the OSCE. Students received a report card of their performance. Small-group leaders of the Introduction to Clinical Medicine course received feedback on their group's performance on each station compared to the class mean. Summative data on class performance was reported to the curriculum committee. The academic status committee received data on students who performed unsatisfactorily. RESULTS: Faculty and examinee ratings of the OSCE experience were very positive. Over the 9-year period, student performance improved showing less variability and significantly fewer failed stations. CONCLUSION: The OSCE has proven to be a technically feasible, authentic evaluation method yielding valuable information for decisions regarding student performance, faculty teaching, and curriculum planning.

Mission-based budgeting: removing a graveyard.

Many activities in today's medical schools no longer have medical students' education as their central reason for existence. Faculty are hired primarily to provide clinical service or to make discoveries, with the role of educator of secondary importance. Budgeting in medical schools has not evolved in concert with these changing roles of faculty. The cost of medical students' education is still calculated as if all faculty were hired primarily to teach medical students and their other activities were to support this "central" mission. Most medical schools still mix revenues without regard to intent and cannot accurately determine costs because they confuse expenses with costs. At the University of Florida College of Medicine, a group of administrators, chairpersons, and faculty developed a budgeting process now called mission-based budgeting. This is a three-step process: (1) revenues are prospectively identified for each mission and then aligned with intended purposes; (2) faculty productivity, i.e., faculty effort and its quality, is measured for each of the missions; and (3) productivity is linked to the prospective budget for each mission. This process allows the institution to understand the intent of its revenues, to measure how productive its faculty are, to learn the true costs of its missions, to make wise investment decisions (subsidies), and to justify to various constituents its use of revenues. The authors describe this process, focusing particularly on methods used to develop a comprehensive database for assessment of faculty productivity in education.

The effect of the duration and structure of a surgery clerkship on student performance.

The emphasis on a generalist professional education has led to shortening and restructuring of the surgery clerkship in the curricula of many medical schools. Little data exist regarding the effect of these changes on student performance. Therefore, we examined the effect of the length, timing, and content of the third year surgery rotation on several clerkship and postclerkship performance measures of 487 students from July 1994 to July 1998. In addition, students' perceptions regarding their ability to understand surgical disease topics were surveyed. The 8-week clerkship (n = 232) was associated with higher NMBE surgery test scores (510.5 +/- 6.3 versus 457.4 +/- 10.0, P < 0.05) resulting in higher final clerkship grades (5.15 +/- 0.04 versus 4.87 +/- 0.03, P < 0.05). Although clerkship length had no significant effect on USMLE step 2 total or surgery subsection scores, the longer clerkship was associated with higher total (70.6 +/- 0.37 versus 68. 8 +/- 0.50, P < 0.05) and abdominal pain station (81.87 +/- 0.71 versus 79.54 +/- 0.73, P < 0.05) OCSE scores. Students rotating on surgery during the second half of third year (n = 233) had higher NMBE surgery test scores (513.1 +/- 8.9 versus 460.5 +/- 11.2, P < 0. 05) and final grades (5.17 +/- 0.03 versus 4.81 +/- 0.04, P < 0.05). Although the timing of the surgery clerkship did not significantly affect total OSCE scores, students who rotated on surgery in the second half of third year performed significantly better year on the abdominal pain OSCE station (80.47 +/- 0.92 versus 76.49 +/- 1.27, P < 0.05). Students who rotated on general surgery (n = 298) performed significantly better on the NBME surgery test (525.6 +/- 6.0 versus 459.6 +/- 9.1, P < 0.05), although this did not significantly affect the final grade. Although general versus subspecialty surgery rotation did not significantly affect total OSCE scores, students rotating on general surgery performed significantly better on the abdominal pain OSCE station (81.21 +/- 0.91 versus 78.17 +/- 0.32, P < 0.05). The length, timing, and content of the third year surgery rotation had no significant effect on performance on the oral examination. Students who had a 6-week clerkship and students who lacked exposure to general surgery felt their surgery rotation failed to prepare them to understand a number of surgical topics as well as students who had an 8-week clerkship or students who rotated on general surgery. The length, timing, and content of the surgery clerkship affect some clerkship performance measures and student perceptions of their understanding of surgical disease topics. While cognitive differences related to clerkship length are no longer detectable at the end of the third year of medical school, differences related to the acquisition of some clinical skills persist after the surgery clerkship.

Moving a graveyard: how one school prepared the way for continuous curriculum renewal.

From 1991 to 1996, the faculty at the University of Florida College of Medicine initiated several significant changes in its curriculum. These changes, included the introduction of early clinical experience in primary care settings; the enhancement of active learning experiences in small-group settings; production and use of computer-based interactive learning materials; increased clinical teaching in the ambulatory care training in an interdisciplinary primary care clerkship; effective course and faculty evaluation; establishment and use of an assessment center for instruction and performance-based evaluations utilizing standardized patients; creation of a medical education center as the focal point for logistics support of the teaching faculty and education data handling; creation of a faculty development program; and initiation of mission-based budgeting based on the faculty's teaching effort and quality. Because the faculty were relatively conservative, it was important to identify variables that would facilitate the introduction of changes and those that might hinder it. The following factors were most important: interest and support by the dean and clearly defined delegation of authority to an associate dean; introduction of a mission-based budgeting process that allocates education funds on the basis of faculty teaching effort and its quality; a clear understanding of the empowerment of the curriculum committee; and an identification of the principles that should guide educational planning and implementation. These efforts are considered the beginning of the continuous renewal needed to respond to information networking, scientific and technological innovations, and the fundamental changes in health care delivery. As these changes have taken place, a shift toward greater institutional control of the educational program leading to the MD degree has been evident.

Pregnancy-specific beta 1-glycoprotein messenger ribonucleic acid and immunoreactive protein in the rat testis.

Human pregnancy-specific beta 1-glycoprotein (PS beta G) is synthesized in large quantities by syncytiotrophoblasts of the placenta. Recent studies using a partial cDNA of PS beta G isolated from human term placenta detected the presence of mRNA highly homologous to placental PS beta G in a number of extraplacental tissues, including human and rat testis. The present study determined in the rat that the amount of PS beta G mRNA based on percentage of total tissue RNA was greatest in the testis of mature rats, followed by senescent and prepubertal rats. In experiments using rats with testicular feminization syndrome (Tfm) which exhibit end-organ insensitivity to androgen stimulation, slot blot analysis of testicular RNA showed reduced levels of PS beta G mRNA in Tfm rats compared to normal rats. Northern blot analysis of rat testicular RNA probed with a human placental PS beta G cDNA demonstrated the presence of a single mRNA species of 1.65 kilobases. Subsequent studies investigated whether proteins immunologically similar to PS beta G were present in the testes from normal and Tfm rats. The rat testes were perfused with fixative, and sections from paraffin-embedded tissues were treated with rabbit anti-human PS beta G, followed by the avidin-biotin-peroxidase complex. Testes from the normal rat showed intense immunostaining in late spermatids (steps 16, 17, 18, and 19 of spermiogenesis), residual bodies, as well as cytoplasm of Leydig cells. Spermatozoa within the epididymis also demonstrated intense immunolabeling. Paraffin sections of the testes from the Tfm rat showed light diffuse cytoplasmic immunostaining in cells of the seminiferous tubules. Since spermiogenesis does not proceed normally, and no spermatids were seen, it was not possible to accurately stage the seminiferous tubules of the Tfm rat. The Leydig cells of the Tfm testes stained intensely, however, as was observed in the testes of the normal rat. These data suggest that the rat may provide an animal model for the investigation of the biological function and regulation of PS beta G in the testis.

Dehydrodolichyl diphosphate synthase in Sertoli and spermatogenic cells of prepuberal rats.

The specific activity of 2,3-dehydrodolichyl diphosphate synthase in homogenates of protease-treated seminiferous tubules, enriched spermatogenic cells, and Sertoli cells changed as a function of the age of prepuberal rats. The highest enzymatic activity occurred in each case in 23-day-old rats. Homogenates of pachytene spermatocytes, spermatids, or Sertoli cells had higher synthase activity than a whole testicular homogenate prepared by protease treatment of tubules. Enzymatic activity in pachytene spermatocytes expressed per mg of protein was about 1.7-fold higher than in spermatids, 5.3-fold higher than in spermatogonia, and about 8.3-fold higher than in spermatozoa. Therefore, the increase in spermatogenic cell synthase before day 23 can be accounted for by the appearance of the pachytene spermatocytes. Enzymatic activity decreased remarkably after the differentiation of spermatids into spermatozoa. Synthase activity in enriched Sertoli cell preparations was 1.5-2.3-fold higher than in spermatogenic cell preparations between days 15 and 30. Therefore, both spermatogenic cells and Sertoli cells contribute to changes in the enzymatic activity in seminiferous tubules during development. These changes may be important in regulating the availability of dolichyl phosphate for glycoprotein synthesis during early stages of differentiation.

Functional differences between small and large luteal cells of the late-pregnant vs. nonpregnant cow.

This paper describes an in vitro model for the study of two types of steroidogenic luteal cells from cows in different physiological states. Two different populations of enzymatically dispersed bovine luteal cells were separated on the basis of size in a Cel-Sep Sedimentation Chamber. The separated small (12.5-23 micron in diameter) and large (greater than 23 micron in diameter) luteal cells of late-pregnant cows (Days 190-280) contained the distinct morphological characteristics previously defined for these two populations of cells. Cells were evaluated for progesterone (P4) production during a 3-h incubation with and without bovine luteinizing hormone (bLH, 10 ng/ml). Both small and large luteal cells from the late-pregnant cow were found to contain equal levels of P4 at Time 0 and increased but equal levels of P4 after a 3-h incubation. Neither cell type showed an increase in P4 production in response to the addition of bLH (p greater than 0.05). Since these results differed from earlier reports for luteal cells of the nonpregnant cow, small and large luteal cells of the mid-cycle (Day 14) were incubated, and the levels of P4 production were compared with P4 levels from the late pregnant cow. In agreement with previous reports for nonpregnant cows, progesterone content at Time 0 was 7-fold higher in large cells than in small cells (p less than 0.05), and after 3 h of incubation, 13-fold higher (p less than 0.05). Although the small cells responded to the presence of bLH in the incubation medium with a 4-fold increase in P4 production, this increase was not significant (p greater than 0.05). The large cell did not respond to bLH. However, the large cell type continued to contain and produce more P4 than did the small cells treated with bLH. This study indicates that both the small and large luteal cells of late-pregnancy are able to produce P4. However, the large luteal cell of the estrous cycle produces greater quantities of P4 than does the small luteal cell or the large luteal cell of late pregnancy.

Biosynthesis of specific histones during meiotic prophase of mouse spermatogenesis.

A kinetics study has demonstrated histone synthesis occurring at two distinct phases during meiotic prophase of mouse spermatogenesis. These two periods have been delineated by quantifying the synthesis of DNA and basic nuclear proteins in spermatogenic cells at discrete intervals following the intratesticular injection of [3H] thymidine and [14C] arginine, respectively. One phase of histone synthesis occurs coincident with DNA synthesis in preleptotene spermatocytes. By contrast, a second phase of histone synthesis occurs during midprophase of meiosis, independent of semiconservative DNA synthesis. The [14C] arginine incorporated into the basic nuclear proteins of pachytene spermatocytes is conserved during spermiogenesis and then subsequently discarded within the residual bodies, which are formed during late spermiogenesis. Fluorographic analyses of isotopically labeled basic nuclear proteins in pachytene spermatocytes has shown that only the somatic complement of histones are synthesized during the preleptotene period, whereas the second phase involves the synthesis of proteins H1t, H2S, and "A". In addition, several nonhistone basic nuclear proteins are synthesized concomitant with the germ cell-specific histones. Thus, the data clearly demonstrate that pachytene spermatocytes actively synthesize a number of novel chromatin-associated polypeptides.

Localization of a single sperm membrane autoantigen (RSA-1) on spermatogenic cells and spermatozoa.

The rabbit sperm membrane autoantigen RSA-1 is a sialoglycoprotein of 13,000 daltons which first appears on the surface of pachytene spermatocytes. Using specific antiserum to RSA-1 the antigen has been localized by immunofluorescence and immunoperoxidase staining. On testicular cells labeled at 37 degrees C, RSA-1 is seen in patches on the surfaces of pachytene spermatocytes, round spermatids, and over the acrosomal area of later spermatids and spermatozoa. Over the postacrosomal and middle-piece regions of late spermatids and spermatozoa the labeling appears uniform. The uniformity can be seen to stop abruptly at the equatorial segment-postacrosomal border. Labeling cells after fixation gives a uniform distribution of label over the surface where patches were seen at 37 degrees C. The polypeptides recognized by the antiserum used for labeling were identified by immunoadsorbent chromatography and subsequent SDS-PAGE. In testicular cells anti-RSA-1 recognizes the 13,000-dalton form and another component which migrates with the dye front. In ejaculated spermatozoa anti-RSA-1 recognizes a distinct ejaculate complex of higher-molecular-weight proteins containing an 84,000-dalton major band and five minor components.

Characterization of Sertoli cell-germ cell junctional specializations in dissociated testicular cells.

To further characterize Sertoli cell-germ cell junctional specializations seminiferous tubules from sexually mature Sprague-Dawley rats were dissociated by enzymatic and mechanical methods. Ultrastructural analysis of cell suspensions prepared by incubation in collagenase alone or by mechanical methods revealed that spermatids remained attached to Sertoli cells or Sertoli cell fragments. Such cellular associations were found only between Sertoli cell fragments and spematids in which the developing acrosome had made contact with the plasma membrane (step 8 and subsequent steps of spermiogenesis). Furthermore, the fragments were confined to that region of the plasma membrane over the acrosome. The Sertoli cell half of this adhesive site displayed the typical elements of Sertoli cell junctions, filamentous bundles and associated cisterna of endoplasmic reticulum, in apposition to the spermatids. The spermatids demonstrated no surface specializations at the attachment sites. In contrast, in cell suspensions prepared with trypsin, spermatids were free of attachments to Sertoli cells or their fragments. These results demonstrate that: (1) the junctions act to bind cells together, (2) adhesive type contact is established between Sertoli cells and spermatids at step 8 and subsequent steps of spermiogenesis, (3) contact is restricted to the spermatid plasma membrane over the acrosome, and (4) spermatids can be freed from the junctional specializations by treatment with trypsin.

The effects of temperature and glucose on protein biosynthesis by immature (round) spermatids from rat testes.

A method is described for the preparation of highly purified fractions (greater than 80% pure) of immature spermatids (round, steps 1--8) from rat testes by centrifugal elutriation in sufficient yields for biochemical studies when four rat testes are used. Electron microscopy established the identity of the cells and demonstrated that the cell membrane is intact. Some cells develop nuclear and cytoplasmic vacuoles during the 2 h required for preparation. Immature spermatids prepared by this method use glucose with an increase in oxygen consumption, lactate production, and protein synthesis over control levels (no glucose). The testicular cell suspension from which spermatids are separated, like whole testis and spermatids themselves, show higher incorporation of amino acids into TCA-precipitable material at 34 degrees C than at 38 degrees C and in the presence of glucose. A subcellular system prepared from immature spermatids with excess ATP shows greater incorporation of amino acids into TCA-precipitable material at 34 degrees C than at 38 degrees C. This difference does not result from increased breakdown of protein. It is concluded that body temperature (38 degrees C) inhibits some aspect(s) of protein synthesis in addition to previously reported effects on amino acid transport and production of ATP (Means and Hall. 1969. Endocrinology. 84:285--297.).

Isolation and separation of highly enriched fractions of viable mouse gastric parietal cells by velocity sedimentation.

Methods of tissue dissociation and cell separation have been modified to obtain highly enriched fractions of mouse gastric parietal cells. Suspension of gastric mucosal cells are prepared by pronase digestion of the glandular portion of the stomach from adult mice. By utilizing the velocity sedimentation technique to separate cells of different sizes it is possible to recovery parietal cells, which are larger than the other cell types, in fractions with purity of 75-95%. The homogeneity of cell fractions has been assessed by light and electron microscopy. The ability of the isolated cells to exclude the dye trypan blue, to incorporate labeled substrate, to consume oxygen, and to retain their structural integrity indicates that they are viable and still capable of functional activity.

Intraepithelial lymphocytes in the male reproductive tract of rats and rhesus monkeys.

Although lymphocytes are never present in 'normal ' seminiferous epithelium, they are found in the terminal portions of the seminiferous tubles near their junctions with the tubuli recti. Intraepithelia lymphocytes are also found in the tubuli recti testis, ductuli efferentes, epididymis and ductus deferens. The ultrastructural morphology of these cells closely resembles that of the intraepithelial lymphocytes in the intestinal mucosa and those obtained from the lymph nodes, spleen blood and thoracic duct. The mucleus is spherical and is characterized by clumps of chromatin near the nuclear membrane. A thin rim of cytoplasm is usually found, and is remarkably free of most cell organelles except for free ribosomes. Frequently, a blunt cytoplasmic process can be seen extending from one end of the cell. Membrane-bounded granules and other dense bodies are occasionally encountered in the cytoplasm. The possible functional significance of intraepithelial lymphocytes in the male reproductive tract is discussed.