IU Indianapolis ScholarWorks :: Browsing by Author "Seifert, Mark F."

Browsing by Author "Seifert, Mark F."

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Cell Kinetics of Osteoblast Histogenesis in Evolving Rabbit Secondary Haversian Systems Using a Double Labeling Technique with [³H]-Thymidine and Bromodeoxyuridine
(1995) Sim, Yeongsuk; Roberts, Eugene; Garetto, Lawrence P.; Katona, Thomas R.; McDonald, James L.; Seifert, Mark F.
The mechanism for internal cortical bone remodeling is orchestrated by the evolving secondary Haversian systems (SHSs), which originate on the surfaces of Volkmann's canals. During this coupled process, a cortical tunnel advances by the cutting cone of osteoclasts and closes by the bone-forming trail of osteoblasts. This study investigated the hypothesis that osteoblast histogenesis, within evolving SHSs of larger animals, is a vascular-related process, i.e., less differentiated osteogenic cells reside in close proximity to the advancing central blood vessel (CBV) while differentiating osteoblast precursors migrate toward the bone surface and become osteoblasts. Using a double-labeling method with [3 H]-thymidine and bromodeoxyuridine (BrdU), this study examined cell kinetics in 120 SHSs per rabbit at 12 hour intervals up to 72 hours after labeling. A total of 7 rabbits were injected with alizarin complexone (-1 O days: 20 mg/kg/day), tetracycline (-3 days: 10 mg/kg/day), [3H]-thymidine (time zero: 0.25 μCi/gm), and BrdU (1 hour before sacrifice: 25 mg/kg). The femoral midshaft was used for undecalcified fluorescent microscopic analysis of new bone vs. old bone and two adjacent diaphyseal tissues were demineralized for nuclear volume morphometric analysis of cells via light microscopy. Evolving SHSs demonstrating intense remodeling activity were selected for detailed cell kinetic analysis. The results showed that BrdU labeled cells were consistently located at the leading edge of the CBV (within 160 μm of its tip) and that the [3H]thymidine labeled cells were progressively left behind the advancing CBV (160 μm from the tip of CBV by 72 hours). The labeling indices (sampled 1 hour after labeling) between BrdU (10.6 ± 0.3 %) and [3H]-thymidine (14.4 ± 1.3 %) were comparable. Lightly labeled A+A' cells (identified as osteoprogenitor cells) remained in close approximation to the surface of the CBV (within 25 μm) and C+D cells (preosteoblasts) were located closer to bone-forming surfaces (~50 μm away from the CBV). The number of osteoblasts were increased up to 60 hours and about 22.5 ± 6.6 % of them survived to become osteocytes. The B cell compartment, characteristic of osteogenic tissues with a dense connective tissue component such as the periodontal ligament (POL), was essentially absent in the SHSs in this study. Although the direction of evolving SHSs was highly variable (caudally directed: 53.4 ± 11.2 % and rostrally directed: 41.6 ± 8.1 %), the osteogenic process along the advancing CBV was remarkably consistent. These results support the hypothesis that osteoblast histogenesis, associated with cortical bone remodeling, is a vascular-oriented differentiation process closely related to the internal angiogenesis within the evolving SHS. The primary proliferating region supporting osteogenesis was consistently located at the advancing tip of the CBV, suggesting the presence of a self-renewing, perivascular proliferative pool of cells accompanying the advancing vessel. In addition, a secondary proliferating region of cells trails the advancing CBV, providing for lateral migration of preosteoblasts to bone surfaces where they complete their development into functional osteoblasts. This study provides further insight into the similarities and differences in osteoblast histogenesis within evolving SHSs from adult rabbits and the more extensively studied rat POL model.
Does time matter? : a search for meaningful medical school faculty cohorts
(2014-12) Guillot III, Gerard Majella; Palmer, Megan M.; Dankoski, Mary E.; Nelson Laird, Thomas F.; Seifert, Mark F.; Shew, Ronald L.
Background. Traditionally, departmental appointment type (basic science or clinical) and/or degree earned (PhD, MD, or MD-PhD) have served as proxies for how we conceptualize clinical and basic science faculty. However, the landscape in which faculty work has considerably changed and now challenges the meaning of these cohorts. Within this context I introduce a behavior-based role variable that is defined by how faculty spend their time in four academic activities: teaching, research, patient care, and administrative duties. Methods. Two approaches to role were compared to department type and degree earned in terms of their effects on how faculty report their perceptions and experiences of faculty vitality and its related constructs. One approach included the percent of time faculty spent engaged in each of the four academic activities. The second approach included role groups described by a time allocation rubric. This study included faculty from four U.S. medical schools (N = 1,497) and data from the 2011 Indiana University School of Medicine Faculty Vitality Survey. Observed variable path analysis evaluated models that included traditional demographic variables, the role variable, and faculty vitality constructs (e.g., productivity, professional engagement, and career satisfaction). Results. Role group effects on faculty vitality constructs were much stronger than those of percent time variables, suggesting that patterns of how faculty distribute their time are more important than exactly how much time they allocate to single activities. Role group effects were generally similar to, and sometimes stronger than, those of department type and degree earned. Further, the number of activities that faculty participate in is as important a predictor of how faculty experience vitality constructs as their role groups. Conclusions. How faculty spend their time is a valuable and significant addition to vitality models and offers several advantages over traditional cohort variables. Insights into faculty behavior can also show how institutional missions are (or are not) being served. These data can inform hiring practices, development of academic tracks, and faculty development interventions. As institutions continue to unbundle faculty roles and faculty become increasingly differentiated, the role variable can offer a simple way to study faculty, especially across multiple institutions.
Grit and beliefs about intelligence: the relationship and role these factors play in the self-regulatory processes involved in medical students learning gross anatomy
(2015-05) Fillmore, Erin Paige; Helfenbein, Robert J.; Palmer, Megan M.; Seifert, Mark F.; Shew, Ronald L.; Brokaw, James J.
Background: Gross anatomy is a foundational medical school course upon which other courses and patient care is grounded; however, variability in student performance suggests potential in studying underlying non-academic factors to explain some of these inconsistencies. Thus, this study examined medical students’ implicit theories of intelligence (ITI) and grit in order to better understand student learning outcomes in gross anatomy. Methods: A mixed methods study was conducted using 2nd, 3rd, and 4th year medical students who successfully completed gross anatomy. Students (n=382) completed the ITI Scale and Short Grit Scale in order to identify individual’s ITI and grit scores. Subsequent interviews (n=25) were conducted to explore how medical students set goals, operated while reaching those goals, and monitored their progress in achieving those goals. Results: Entity and incremental theorists with high grit performed significantly better in gross anatomy when compared to those with low grit. Further, highly gritty incremental and entity theorists were hard workers and showed resilience in the face of challenges. Specifically, those with an entity ITI had the central goal of getting an honors grade, while those with an incremental ITI desired to understand and apply their anatomical knowledge. Conversely, low grit individuals became overwhelmed by challenges, were more likely to show an inconsistent work ethic, and questioned their ability to master the material. An individual’s ITI, more so than grit, drove the presence of negative emotions in a medical student, with entity theorists feeling anxious and vulnerable, and incremental theorists feeling fewer negative emotions. Finally, grit level moderated how a medical student would respond to negative emotions, with highly gritty individuals exhibiting more constructive coping mechanisms. Conclusions: These findings suggest that medical students who possess high grit and an incremental theory of intelligence have the most effective learning strategies, set achievable goals, and enlist effective coping mechanisms while learning gross anatomy. The findings and tools used in this study could be incorporated into the medical school admissions process. Finally, findings reinforce the value of examining the ITI and grit of medical students, as they can provide educators with insight regarding important non-academic factors driving learning in gross anatomy.
The professionalization of medical students : a longitudinal analysis of professional identity formation and professionalism perceptions in second and third year medical students
(2017-12) Byram, Jessica Nichole; Scheurich, James J.; Brokaw, James J.; Hoffman, Leslie A.; Seifert, Mark F.; Hoffmann-Longtin, Krista
Background: Recent literature on professional identity formation (PIF) conceptualizes the developmental process into stage theories that remove critical context. This study employed a longitudinal approach to PIF that explored the processes through which professional identity is formed in second (MS2) and third (MS3) year medical students and how their perceptions of professionalism transformed and influenced their PIF. Methods: Nine medical students (n=9) from Indiana University School of Medicine completed this study spanning MS2 and MS3. Participants completed three semi-structured interviews and submitted 10 audio diaries at two-month intervals between interviews. Participants also completed the Professionalism Assessment Tool (PAT) at the beginning of MS2 (PAT1) and end of MS3 (PAT2). Interviews and audio diaries were analyzed using the constant comparative approach and a Wilcoxon signed-rank test was used to determine significant differences between mean domain scores of PAT1 and PAT2. Results: This study found several processes of PIF within five themes: Exploring Self in Medicine, Connecting to Image of Medicine, Embodying Role, Internalizing Values, and Exploring Specialty Choice. Processes of participating in patient care and selecting a specialty have the most profound impact on PIF and resulted in medical students feeling like members of the medical community. Analyses revealed participants’ perceptions of professionalism became more complex with clinical experiences and their perceptions of their ability to enact those behaviors transformed across the study period. Furthermore, the participants’ perceptions of professionalism set the foundation for the values they desired to demonstrate as part of their professional identities. Conclusions: This study presents a cohesive picture of how PIF occurs across MS2 and MS3 and how professionalism influences this important developmental process. These results indicate PIF is best cultivated within a medical curriculum where students are able to utilize processes to foster its development. Since professionalism serves as an important foundation to professional identity and a comprehensive understanding is needed for medical students to appreciate a physician’s role in society, the curriculum must be structured in a way to promote a complex, reflective understanding of professionalism that is based on values, actions, and who one wants to be as a physician.
A Psychometric Evaluation of Script Concordance Tests for Measuring Clinical Reasoning
(2013-06) Wilson, Adam Benjamin; Pike, Gary R. (Gary Robert), 1952-; Humbert, Aloysius J.; Brokaw, James J.; Seifert, Mark F.
Purpose: Script concordance tests (SCTs) are assessments purported to measure clinical data interpretation. The aims of this research were to (1) test the psychometric properties of SCT items, (2) directly examine the construct validity of SCTs, and (3) explore the concurrent validity of six SCT scoring methods while also considering validity at the item difficulty and item type levels. Methods: SCT scores from a problem solving SCT (SCT-PS; n=522) and emergency medicine SCT (SCT-EM; n=1040) were used to investigate the aims of this research. An item analysis was conducted to optimize the SCT datasets, to categorize items into levels of difficulty and type, and to test for gender biases. A confirmatory factor analysis tested whether SCT scores conformed to a theorized unidimensional factor structure. Exploratory factor analyses examined the effects of six SCT scoring methods on construct validity. The concurrent validity of each scoring method was also tested via a one-way multivariate analysis of variance (MANOVA) and Pearson’s product moment correlations. Repeated measures analysis of variance (ANOVA) and one-way ANOVA tested the discriminatory power of the SCTs according to item difficulty and type. Results: Item analysis identified no gender biases. A combination of moderate model-fit indices and poor factor loadings from the confirmatory factor analysis suggested that the SCTs under investigation did not conform to a unidimensional factor structure. Exploratory factor analyses of six different scoring methods repeatedly revealed weak factor loadings, and extracted factors consistently explained only a small portion of the total variance. Results of the concurrent validity study showed that all six scoring methods discriminated between medical training levels in spite of lower reliability coefficients on 3-point scoring methods. In addition, examinees as MS4s significantly (p<0.001) outperformed their MS2 SCT scores in all difficulty categories. Cross-sectional analysis of SCT-EM data reported significant differences (p<0.001) between experienced EM physicians, EM residents, and MS4s at each level of difficulty. When considering item type, diagnostic and therapeutic items differentiated between all three training levels, while investigational items could not readily distinguish between MS4s and EM residents. Conclusions: The results of this research contest the assertion that SCTs measure a single common construct. These findings raise questions about the latent constructs measured by SCTs and challenge the overall utility of SCT scores. The outcomes of the concurrent validity study provide evidence that multiple scoring methods reasonably differentiate between medical training levels. Concurrent validity was also observed when considering item difficulty and item type.

Browsing by Author "Seifert, Mark F."

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