Extended abstract of a paper presented at Microscopy and Microanalysis 2005 in Honolulu, Hawaii, USA, July 31--August 4, 2005

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Polychlorinated biphenyls (PCBs) are ubiquitous and persistent environmental contaminants. In mammals, PCBs affect spermatogenesis and may be associated with Sertoli cell changes. Therefore, our aim was to evaluate in vitro toxic effects of hydroxylated PCB (PCB-22; 2',3',4',5'-tetrachloro-4-biphenylol) and PCB congener (PCB-77; 3,3',4,4'-tetrachlorobiphenyl) on Sertoli cells isolated from 19- to 21-day-old male rats. Sertoli cells incubated for 24 hours in 10(-7) M PCB-22 and 10(-8) M PCB-77, but not in 0.05% ETOH or 10(-7) M 17beta-estradiol (E2) showed morphological changes. Sertoli cells demonstrated progressive damage with higher concentrations of PCB-77 (10(-7) M). After 24 hours, 10(-7) M PCB-22 killed 20% of the Sertoli cells and equimolar PCB-77 killed 45% of the Sertoli cells in culture. At 10(-8) M, PCB-22 did not kill any significant number of Sertoli cells, whereas PCB-77 killed 40% of cells in culture. This result showed differential effects of PCB compounds, with PCB-77 being more cytotoxic than PCB-22 as tested on Sertoli cells. Because PCB-77 produced greater toxic effects, we further tested this congener on Sertoli cell lactate production. After 24 hours, lactate production by Sertoli cells treated with 10(-7) or 10(-8) M PCB-77 was significantly increased. Finally, Sertoli cells exposed to 10(-7) M PCB-77 showed disorganized and less intense F-actin staining. The results demonstrate that PCBs, but not E2, is directly toxic to Sertoli cells in vitro, and suggest this toxic effect is independent of estrogenic action.

Alkylphenols, including the estrogenic 4-tert-octylphenol (OP), are environmental pollutants. Because administration of OP to adult male rats impairs spermatogenesis and OP has been shown to be toxic to aquatic animals and to mammalian splenocytes in vitro, we studied whether OP exerts direct toxic effects on cultured spermatogenic cells and Sertoli cells isolated from male rats. Cell viability was assessed with a Live/Dead Eukolight viability/cytotoxicity kit. Culture of mixed spermatogenic cells from adult rats with 10(-8) M OP or Sertoli cells from 19- to 21-day-old rats with 10(-12) M OP, but not with 0.08% EtOH (vehicle) or 10(-6) M 17beta-estradiol (E2) or dexamethasone (DEX), significantly decreased the percentage of viable cells after 24 h of treatment. None of the treatments significantly altered total cell number. Flow cytometric analyses of spermatogenic cells revealed that exposure to 10(-4) or 10(-6) M OP yielded abnormal relative ploidy classes. Four hours of treatment with 10(-6) M OP, but not with 10(-6) M E2 or DEX, caused significant chromatin condensation in Sertoli cells as observed with acridine orange staining. The decreased percentage of viable cells after 24 h of exposure to 10(-6) M OP remained when Sertoli cells were cultured in Ca2+-free medium. Sertoli cells contained nuclei of reduced size and labeled 3'-OH DNA ends as detected by microscopic analyses when the cells had been incubated for 24 h with 10(-6) M OP but not with vehicle or 10(-6) M E2 or DEX. The results demonstrate that OP, but not E2 or DEX, is directly toxic to cultured rat spermatogenic cells and Sertoli cells and suggest that this toxic effect in Sertoli cells is exerted through Ca2+-independent apoptosis.

Advances in every aspect of the art and science of medicine have occurred at a breathtaking pace during the latter half of the 20th century: Watson and Crick demonstrated the structure of DNA in 1953; medical centers throughout the world are transplanting livers, lungs, and mismatched bone marrow. Even cadaver hands may soon be transplanted routinely.15 Mammals can be cloned,18 and stem cells have been used to construct organs as complex as artificial kidneys.3 As a result of this explosion of knowledge in both the basic and clinical sciences, medical school faculties have devoted much time and effort toward revising curricula designed to prepare their students to enter this challenging new world successfully. Changes in the curriculum are often made without extramural consultation. It is no surprise that the results are highly variable. One of the ironies of this educational process is that we train our students in such divergent ways, yet determine their success by requiring them to pass nationally standardized examinations. One of the ironies of this educational process is that we train our students in such divergent ways, yet determine their success by requiring them to pass nationally standardized examinations (United States Medical Licensing Examination [USMLE] Step 1 and Step 2). Furthermore, faculty anticipate that many students will depart their home states to join groups in other parts of the country where they will work together harmoniously with colleagues who have been trained in many different fashions. Our aim in teaching medical microscopic anatomy (MMA) is to train students so that they will be competitive in any setting with graduates taught by traditional or nontraditional methods. As medical school faculty, we often wrestle with issues that impact the methods used to teach MMA. For example: (1) Are students trained as problem solvers, rather than memorizers and regurgitators? (2) How well do our students perform on the USMLE National Board Exams? (3) How well do our students perform in courses which require background knowledge in microscopic anatomy? To these ends, we debate (1) the relevance of our goals and objectives, (2) whether there is adequate integration of course content, both horizontally and vertically, (3) the clinical relevance of the course content, (4) how well we have emphasized problem-based learning skills, and (5) whether we have successfully implemented GPEP (General Professional Education for Physicians) recommendations and LCME (Liaison Committee on Medical Education) accreditation standards. In contemplating these issues (e.g., Hightower et al.11), it occurred to us that our counterparts throughout the United States and Canada may be experiencing similar concerns. We believe it would be advantageous for each of us to know how others have approached these matters. This can be addressed by documenting how the “average” MMA course is currently taught. To date, our impressions are the result of anecdotal evidence and personal conversations with friends and colleagues. No one has published a comprehensive survey designed to explain how a typical MMA course is currently taught to medical students. The importance of histological training for Ph.D. candidates has been discussed recently. 1,13 Askew and Heffelfinger1 concluded that anatomists are well suited to provide training appropriate for interpretation of, for example, phenotypic analysis of the transgenic mouse models now so prevalent in basic research. The objective of our study was to obtain relevant data on the manner in which MMA courses are taught and to relate these observations to current trends in medical education. Clearly these educational and academic concerns are not limited to MMA courses. We note with interest a similar recent discussion of gross anatomy courses in the United States and Canada7 and a more general consideration of the changing nature of anatomy education.5 A questionnaire (see Appendix) was e-mailed in 1998 to appropriate faculty at 89 public or private medical schools in the United States and Canada. Fifty-one completed questionnaires were received during the 1998 calendar year, a return rate of 57% (Table 1). Note that some respondents did not answer all questions. Most responders included additional supplemental information regarding their courses. Whenever possible, we utilized the supplemental data in this report. Several questions were designed to obtain an accurate picture of the type of information that is presented in a typical MMA course in the late 1990s. Respondents were asked: (1) their course titles, (2) whether they would characterize their courses as “traditional” or “nontraditional,” and (3) the types of materials students used to study MMA; specifically, textbooks, atlases, handouts, microscopes, and computers. Approximately three-fourths of the courses were named using some combination of the traditional terms “Microscopic Anatomy,” “Histology,” or “Histology/Cell Biology” (Table 2). Most of the remaining courses were not independent entities, but rather components of integrated curricula. The number of courses with traditional titles was similar to the number of courses termed traditional. Sixty-nine percent of the respondents (34 of 49) gave traditional titles, and 76% of the respondents (38 of 50) considered their courses to be traditional. By contrast, 31% (15 of 49) indicated that their courses were nontraditionally named, and 24% (12 of 50) considered their courses to be nontraditional. This suggests that most of the nontraditionally named courses in the survey were components of integrated curricula. To confirm this, individual responses to these two questions were compared. This comparison demonstrated that 83% of the responders had a traditional course title and also considered their course to be traditional. Despite these differences in classification, both “traditional” and “nontraditional” courses used similar teaching materials. Textbooks, atlases, and microscopes were employed in virtually all courses (Fig. 1). Supplemental information provided by some of the responders indicated that these three teaching materials were emphasized in their courses. Handouts and computers were used in approximately half of the courses, whether “traditional” or “nontraditional” (Fig. 1). Handouts were used only in conjunction with textbooks, although for five courses handouts represented the primary source of information. Computer use was the most variable parameter, regardless of whether the courses were considered traditional or nontraditional. Some courses used computers very little, while one course was taught to students who were required to purchase laptop computers. Teaching materials used to any extent by MMA courses. There were 49 responders to these questions. We also asked which textbook and/or atlas students used. We sought to determine how many courses were using condensed textbooks as opposed to complete, full-length textbooks. Eighty percent of the responders (39 of 49) reported the use of one of three condensed textbooks. They were: (1) Junqueira, Carneiro and Kelley,12 (2) Ross, Romrell and Kaye,14 and (3) Gartner and Hiatt.8 Most of the remaining responders reported using other condensed textbooks (e.g., Stevens and Lowe,16 Cormack,4 Goodman,9 and Wheater's2). Only two responders reported the use of an unabridged textbook (Bloom and Fawcett6). Sixty-eight percent of the responders (32 of 47 courses that used atlases) reported the required or suggested use of one of two atlases: Wheater's2 or Gartner and Hiatt.8 The remaining courses used nine different atlases. An unexpected result was the popularity of two particular books. Gartner and Hiatt 8 and Wheater's2 were used in many courses (Table 3). Twenty-two of the MMA courses required or recommended Gartner and Hiatt8 as either a text, an atlas, or both. Wheater's2 was required or suggested for use in some capacity by 23 of the reporting schools. Note, however, that this latter book was used almost exclusively as an atlas (Table 3). Other prevalent information sources, Ross et al.14 and Junquiera et al.,12 were used by a total of 12 and 15 courses, respectively, predominantly as textbooks. A second set of questions was formulated to determine the significance of the typical MMA course in the medical school curriculum. Specifically, respondents answered questions regarding: (1) contact hours, lecture hours, and laboratory hours, (2) number of students, (3) degree sought by students, and (4) number of instructors. Our data indicate that MMA courses still play a significant role in medical school curricula. Data on contact hours are shown in Figure 2. Total contact hours varied widely from 8 to 170 with a mean of 88. Seventy percent of the courses ranged from 70 to 120 hours. Courses averaged 34 lecture hours, 46 laboratory hours, and 8 exam hours. Total contact hours reported by respondents ranged from 8 to 170 with a mean of 88. Lecture contact hours averaged 34 and laboratory contact hours averaged 46. Laboratory contact remained a significant component in the great majority of courses. Exam hours, which averaged eight, were not plotted. Student census in a typical course was 136 with a range of 25 to 270 (Fig. 3). Approximately three-fourths of these courses were taught to medical students only. The remainder also included either graduate students (19%), dental students (4%), or both (4%). The total number of students enrolled in courses for which data were available ranged from 25 to 270, with a mean of 136. The vast majority were medical students. Although the questionnaire requested only the number of instructors, some responders included supplemental data distinguishing lecturers from other instructors. Other instructors included those faculty teaching solely in the laboratory, graduate teaching assistants, clinical coordinators, or individuals giving the occasional clinical correlation lecture. When responders specified only the total number of instructors, we assumed that all instructors lectured. There was an average of six faculty lecturers (Fig. 4). Supplemental information provided for some courses indicated that graduate students and/or clinical faculty assisted by teaching in the laboratory. In some courses, clinical faculty also lectured. On the other hand, some responders indicated that graduate students were not used in any capacity. Excluding graduate students and clinical faculty, the mean student-faculty ratio was 24 to 1. Participating faculty who lecture were distinguished from non-faculty or occasional guest lecturers. Lecturing faculty averaged six in number. The mean lecturing faculty to student ratio was 24 to 1. Additional questions were structured to determine the manner in which medical students were tested. We asked how often students were quizzed, tested on lecture information, and tested on laboratory material. In addition, we asked whether students took a standardized final exam like the shelf test written by the National Board of Medical Examiners. Moreover, we assessed whether traditional and/or nontraditional testing methods were used. We sought to determine the frequency and types of nontraditional testing methods. The data indicate that quizzes were not popular: only 30% of the courses gave them (Fig. 5). Roughly 80% of the courses administered two to four lecture exams and a similar number of laboratory exams. Respondents unanimously indicated that they tested traditionally (Fig. 6). Some courses added nontraditional means of testing that ranged from computer-generated exams to take-home exams done on the honor system, and/or oral exams and essays. Thirty-nine percent of the courses surveyed evaluated both traditionally and nontraditionally. Finally, 10 responders indicated that standardized tests were used. The number of quizzes and tests was assessed with tests being differentiated into written and laboratory exams. Only 30% of the respondents reported giving quizzes. Two to four written exams and similar number of laboratory exams were given by approximately 80% of all courses for which data were obtained. All respondents reported administering some traditional forms of testing. Standardized testing was not popular. Thirty-nine percent of courses for which data were available evaluated using both traditional and nontraditional methods. We have heard anecdotal evidence of major cuts in time, emphasis, and material allotted to MMA courses. This concerned us. As a result, we attempted to identify the significance of these reputed changes. Our survey asked whether course philosophy had changed during the past few years in response to GPEP, intramural pressure for more clinical contact time, or any other factors. Forty-eight percent of returned questionnaires indicated that major philosophical changes had occurred. Without accurate information regarding the characteristics of pre-GPEP histology courses, we can only speculate on how a widespread change in philosophy has affected the manner in which histology is taught to medical students. However, a general picture of how the typical MMA course was taught in the 1950s and 1960s does exist. Textbooks have changed dramatically, from thousand-page tomes (e.g., Weiss and Greep17 or Ham10) to more concise, visually appealing books characterized by less text and more colorful, eye-catching figures and photomicrographs. Atlases also have changed, mainly in format, with a greater use of photomicrographs as opposed to drawings. Several of the popular books today are combination text-atlases. The aforementioned changes clearly suggest that MMA courses of the 1990s have been streamlined. Unfortunately, sufficient quantitative evidence is not available. Therefore, we do not know precisely how much streamlining has occurred with regard to parameters such as contact hours, subject material, and faculty involvement. In spite of changes in the overall medical curriculum and perceived changes specific to MMA, the present study suggests that core methods for teaching histology have not changed appreciably. The typical MMA course is still taught and tested via traditional pedagogical modalities. The laboratory remains a significant component and microscopes are still an important laboratory tool. These results were unexpected in light of GPEP and its emphasis on problem-solving and self-learning. Upon consideration, however, this finding can be rationalized effectively. Possibly, one of the reasons new teaching modalities have not been used more frequently is that many courses still do use microscopes. Microscopy encourages problem-solving, and self-learning. When used in conjunction with equipment allowing simultaneous viewing by more than one student, microscopy also fosters small-group interaction. Thus, a tool which has been used for many decades continues to be useful and effective in carrying out the goals and objectives of modern MMA courses which are attentive to GPEP and LCME recommendations. We thank Ms. Janice H. Burns for her expertise in typing, distribution of the questionnaire, and data collation. The authors are members of the Department of Cell Biology and Neuroscience in the School of Medicine at the University of South Carolina. Drs. Hightower, Boockfor, and Millette currently teach Medical Microscopic Anatomy (MMA) to entering medical students during the first semester. They have taught the subject for 29, 12, and 22 years, respectively. Dr. Blake is chair of the department and previously taught MMA for 8 years. Between them, they have taught MMA at six different medical schools as faculty. Dr. Hightower is course director of MMA. The course consists of 120 contact hours. It is taught to 75–80 medical students and up to five graduate students yearly. It consists of traditional lectures, laboratories, and exams. A nontraditional take-home essay which involves scientific literature searches and study is also required. A primary goal is for students to learn how to “read” glass slides. This enables them to identify, recognize, and appreciate normal tissues, providing a basis to distinguish normal tissues from abnormal tissues and artifacts. I am writing to you in hopes that you will refer this questionnaire to the most appropriate individual in your department. It shouldn't take more than 5 minutes to complete. In preparing a journal article, I need to know how our Medical Microanatomy course compares with similar courses taught in the United States and Canada. To that end, will you answer the following questions regarding your course? Please be assured that your responses will be confidential. We will collate information from a number of sources to present an overview of a “typical” histology course taught to medical students today. What is the title of the microanatomy course which is taught at your institution? Would you characterize the course as a “traditional” lecture/lab course? Yes/No How many students take the course? Number of contact hours? Number of lecture hours? Number of laboratory hours? Number of individuals who teach the course? Is the course taught primarily to medical (m), dental (d) or graduate (g) students? m/d/g/ Has the course philosophy changed significantly during the past few years in response to GPEP or other extramural or intramural factors? Yes/No Do students use individual microscopes to study glass slides? Yes/No Do students use a textbook? Yes/No If “yes,” which one? Do students use an atlas? Yes/No If “yes,” which one? Do you use handouts instead of a textbook? Yes/No Do you rely heavily (h), moderately (m) or slightly (s) on computer technology? h/m/s/ Are student grades determined by traditional testing methods? Yes/No Number of quizzes in the course? None/1/2/3/4/5/6 or more Number of written exams in the course? None/1/2/3/4/5/6 or more Number of laboratory exams in the course? None/1/2/3/4/5/6 or more Do students take a standardized exam at the end of the course? Yes/No Are students tested in nontraditional ways? Yes/No If your answer to question 20 is “yes,” are the ways essays and reports/oral exams/other? If you circled “other” in question 21, please indicate what you mean.