Implementation and evaluation of a near-peer-facilitated medical ethics curriculum for first-year medical students: a pilot study.

INTRODUCTION: The primary objectives of this study were to implement a novel near-peer-facilitated case-based medical ethics curriculum intended for the audience of a large cohort of first-year medical students (n = 193) and to objectively evaluate the immediate efficacy of the curriculum based on pre- and post-session survey responses to ethical quandaries. METHODS: Two near-peer-facilitated medical ethics case discussion sessions were included in the first-year curriculum during the 2017-2018 academic year. The sessions were designed and led by second-year medical student facilitators under the direction of a faculty mentor and were presented as a year-long curricular thread. First-year students were asked to complete pre- and post-session surveys with ethical questions relevant to each case and session. Students were additionally asked to measure the contribution of discussion sessions to their development as a future physician. RESULTS: Post-session survey results showed that students had a better understanding of specific ethical issues immediately following discussion sessions (p<0.0001). Over three-quarters of students indicated that the near-peer-led medical ethics case discussions contributed somewhat or very much to their development as a future physician. Anecdotal feedback from second-year medical students also suggested that their involvement as facilitators was beneficial to their educational development. CONCLUSION: Near-peer-facilitated case discussions were an effective strategy for teaching medical ethics to first-year medical students with demonstrated objective improvements in ethical decision-making. Additionally, near-peer discussions of ethical cases and principles with first-year medical students aided in subjective measures of professional development.

The body as a living bioreactor: a feasibility study of pedicle flaps for tracheal transplantation.

Reconstruction of long-segment tracheal stenosis remains problematic. Ex vivo transplantation of stem cell-derived tracheas has been established in humans using external tissue bioreactors. These bioreactors, however, are not widely accessible. Thus, we are developing a rotational flap-based "internal bioreactor" to allow in vivo stem cell engraftment in a pre-vascularized recipient bed. This muscle will also then serve as a carrier for the transplanted trachea during rotation into position for airway reconstruction. Herein, we present a study investigating the feasibility of two pedicle muscle flaps for implantation and subsequent tracheal transplantation. Trapezius and latissimus flaps were raised using established surgical techniques. The length and width of each flap, along with the distance from the pedicle takeoff to the trachea, were measured. The overall ability of the flaps to reach the trachea was assessed. Twelve flaps were raised in 5 fresh adult human cadavers. For the trapezius flap, averages were: flap length of 16.4 cm, flap width of 5.95 cm at the tip, and distance from the pedicle takeoff to the trachea of 11.1 cm. For the latissimus dorsi flap, averages were: flap length of 35.4 cm, flap width of 7.25 cm at the tip, and distance from the pedicle takeoff to the trachea of 27.3 cm. All flaps showed sufficient durability and rotational ability. Our results show that both trapezius and latissimus dorsi flaps can be transposed into the neck to allow tension-free closure of tracheal defects. For cervical tracheal transplantation, both flaps are equally adequate. We believe that trapezius and latissimus dorsi muscle flaps are potential tracheal implantation beds in terms of vascular supply, durability, and rotational ability.

Microbial signature lipid profiling and exopolysaccharides: experiences initiated with Professor David C White and transported to Tasmania, Australia.

Developments and applications with signature lipid and exopolysaccharide (EPS) methodologies covering a thirty year period in the DC White laboratories at Florida State University and the University of Tennessee at Knoxville are illustrated. These powerful techniques were used to gain new insight into microbial communities, not obtainable by classical approaches. Selected case examples are highlighted and include: use of a specific dimethyl disulphide (DMDS) derivitization procedure with monounsaturated fatty acids (MUFA) to precisely determine double bond position and geometry; application of the DMDS procedure in taxonomic and environmental studies including the degradation of pollutant halogenated hydrocarbons in groundwater and subsurface aquifers; exploiting the ubiquitous nature of uronic acids in microbial EPS to quantify these exopolymers in complex environmental samples; development of rapid and non-destructive approaches including FT-IR to follow biofilm formation in a unique manner not possible with other approaches. The foundations laid in the DC White laboratories have seen a wide suite of applications in modern microbial ecology and associated fields. The training of young scientists by DC White will also ensure that his unique approach and quest for new and or novel methodologies for use in environmental microbiology will continue.

L-type Ca2+ channel function in the avian embryonic heart after cardiac neural crest ablation.

In avian and mammalian embryos, surgical ablation or severely reduced migration of the cardiac neural crest leads to a failure of outflow tract septation known as persistent truncus arteriosus (PTA) and leads to embryo lethality due partly to impaired excitation-contraction coupling stemming primarily from a reduction in the L-type Ca(2+) current (I(Ca),(L)). Decreased I(Ca,L) occurs without a corresponding reduction in the alpha(1)-subunit of the Ca(2+) channel. We hypothesize that decreased I(Ca),(L) is due to reduced function at the single channel level. The cell-attached patch clamp with Na(+) as the charge carrier was used to examine single Ca(2+) channel activity in myocytes from normal hearts from sham-operated embryos and from hearts diagnosed with PTA at embryonic days (ED) 11 and 15 after laser ablation of the cardiac neural crest. In normal hearts, the number of single channel events per 200-ms depolarization and the mean open channel probability (P(o)) was 1.89 +/- 0.17 and 0.067 +/- 0.008 for ED11 and 1.14 +/- 0.17 and 0.044 +/- 0.005 for ED15, respectively. These values represent a normal reduction in channel function and I(Ca),(L) observed with development. However, the number of single channel events was significantly reduced in hearts with PTA at both ED11 and ED15 (71% and 47%, respectively) with a corresponding reduction in P(o) (75% and 43%). The open time frequency histograms were best fitted by single exponentials with similar decay constants (tau approximately or equal 4.5 ms) except for the sham operated at ED15 (tau = 3.4 ms). These results indicate that the cardiac neural crest influences the development of myocardial Ca(2+) channels.