Efficacy of Video-Based Forearm Anatomy Model Instruction for a Virtual Education Environment.

INTRODUCTION: As virtual education becomes more widespread, particularly considering the recent COVID-19 pandemic, studies that assess the impact of online teaching strategies are vital. Current anatomy curriculum at Paul L. Foster School of Medicine consists of self-taught PowerPoint material, clinical vignette-centered team-based learning (dry lab), and prosection-based instruction (wet lab). This study examined the impact of video-based muscle model (VBMM) instruction using a student-designed forearm muscle model on anatomy quiz scores and student perceptions of its effectiveness with regards to learning outcomes. METHODS: Students divided into Group 1 (54 students) and Group 2 (53 students) were assessed prior to and following a 3.5-minute video on anterior forearm compartment musculature using the muscle model. Group 1 began by completing a pretest, then received VBMM instruction, and then completed a posttest prior to participating in the standard dry lab and 1 hour wet lab. Group 2 completed the wet lab, then received the pretest, VBMM instruction, and posttest prior to participating in the dry lab. Both groups took an identical five-question quiz covering locations and functions of various anterior forearm muscles each time. RESULTS: Mean scores were higher than no formal intervention with exposure to VBMM instruction alone (0.73 points, P = .01), wet lab alone (0.88 points, P = .002), and wet lab plus VBMM instruction (1.35 points, P= <.001). No significant difference in scores was found between instruction with VBMM versus wet lab alone (P = 1.00), or between either instruction method alone compared to a combination of the two methods (P = .34, .09). Student survey opinions on the VBMM instruction method were positive. CONCLUSION: VBMM instruction is comparable to prosection-based lab with regards to score outcomes and was well received by students as both an independent learning tool and as a supplement to cadaveric lab. When compared to either instruction method alone, the supplementation of VBMM with cadaveric prosection instruction was best. VBMM instruction may be valuable for institutions without access to cadaveric specimens, or those looking to supplement their current anatomy curriculum.

Predictability of Lower Extremity Peripheral Nervous Anatomy.

Lower extremity nervous anatomy is highly variable. This study sought to determine relationships of lower extremity peripheral nerves to anatomic landmarks. Sixteen well-preserved lower extremities were dissected. The distance from each nerve point of interest to relevant landmarks was measured in standardized fashion. The sciatic nerve divided on average 26.0% ± 5% of the distance from the superior aspect of the fibula to the greater trochanter proximal to the knee joint line [Pearson correlation coefficient (PCC) D 0.764]. The superficial peroneal nerve pierced the crural fascia at an average of 28.0% ± 6% of the fibular length proximal to the lateral malleolus (PCC D 0.718). The deep peroneal nerve emerged between the tibialis anterior and extensor hallucis longus on average 2.7% ± 0.4% of the fibular length proximal to the tibiotalar joint line (PCC D 0.530). While there was substantial variability in the course of lower extremity peripheral nerves, the study found strong correlation with femur and fibula length within each specimen. (Journal of Surgical Orthopaedic Advances 26(4):206-210, 2017).

Clinical considerations of the glandular branch of the lacrimal artery.

The lacrimal artery is classically described as a branch of the ophthalmic artery supplied by the internal carotid. In this study, 25 orbits were dissected to identify variations in glandular branching and to compare them to previously published accounts. The glandular branching patterns of the lacrimal artery fall into two categories, those that branch (56%) and those that do not branch (44%). We found the medial and lateral glandular branches to be equal in diameter with a divergence of 2.67-40.58 mm proximal to the gland parenchyma. The long glandular branches run alongside the superolateral aspect of the orbit. The lateral branch runs lateral to the lateral rectus muscle. The medial branch runs superomedial to the lateral rectus muscle and lateral to the superior rectus muscle. In relation to the lacrimal gland, the medial branch enters the superior aspect of the gland parenchyma and the lateral branch enters its inferior aspect. The average branch lengths were 17.88 mm (medial) and 13.51 mm (lateral) as measured with a Mitutoyo Absolute 1/100 mm caliper. We could not confirm the existence of a third branch supplying the lacrimal gland, as posited by other authors. The key finding in this study is that the lacrimal gland is predominantly supplied by two significant arterial branches, both of which must be identified during procedures involving the lateral orbit.

Patterns of innervation of the lacrimal gland with clinical application.

Parasympathetic stimulation of the lacrimal gland is responsible for tear production, and this innervation originates from fibers conveyed in the facial nerve. After synapse in the pterygopalatine ganglion, postsynaptic parasympathetic fibers travel within the zygomatic and zygomaticotemporal nerves (ZTN) into the orbit. As described in most anatomy texts, ZTN communicates with the lacrimal nerve (LN) posterior to the gland and then secretomotor fibers enter the gland. This study was performed to gain a better understanding of the innervation of the lacrimal gland. Seventeen cadaver heads were bisected for a total of 34 sides, which then underwent dissection of the superolateral orbital region to observe the course for the LN and ZTN. Three variations of the course of the LN and ZTN were found. In 20 (60.6%) dissections it was documented that the ZTN entered directly into the lacrimal gland with no communication with the LN. In 12 (36.4%) of the bisected heads, ZTN had both a direct connection into the gland and a communicating branch with the LN. In only one (3.0%) bisected head, ZTN communicated with the LN before entering the gland as it is commonly described in anatomy texts. Our study reveals that the ZTN usually takes a different course than is classically described in most anatomy textbooks. A greater understanding of the typical course these nerves take may help surgeons identify them more easily and avoid damaging them.

The cochaperone SGTA (small glutamine-rich tetratricopeptide repeat-containing protein alpha) demonstrates regulatory specificity for the androgen, glucocorticoid, and progesterone receptors.

Steroid hormone receptors are ligand-dependent transcription factors that require the ordered assembly of multichaperone complexes for transcriptional activity. Although heat shock protein (Hsp) 90 and Hsp70 are key players in this process, multiple Hsp70- and Hsp90-associated cochaperones associate with receptor-chaperone complexes to regulate receptor folding and activation. Small glutamine-rich tetratricopeptide repeat-containing protein alpha (SGTA) was recently characterized as an Hsp70 and Hsp90-associated cochaperone that specifically regulates androgen receptor activity. However, the specificity of SGTA for additional members of the steroid hormone receptor superfamily and the mechanism by which SGTA regulates receptor activity remain unclear. Here we report that SGTA associates with and specifically regulates the androgen, glucocorticoid, and progesterone receptors and has no effect on the mineralocorticoid and estrogen receptors in both yeast and mammalian cell-based reporter assays. In both systems, SGTA knockdown/deletion enhances receptor activity, whereas SGTA overexpression suppresses receptor activity. We demonstrate that SGTA binds directly to Hsp70 and Hsp90 in vitro with similar affinities yet predominately precipitates with Hsp70 from cell lysates, suggesting a role for SGTA in early, Hsp70-mediated folding. Furthermore, SGTA expression completely abrogates the regulation of receptor function by FKBP52 (52-kDa FK506-binding protein), which acts at a later stage of the chaperone cycle. Taken together, our data suggest a role for SGTA at distinct steps in the chaperone-dependent modulation of androgen, glucocorticoid, and progesterone receptor activity.

Targeting the regulation of androgen receptor signaling by the heat shock protein 90 cochaperone FKBP52 in prostate cancer cells.

Drugs that target novel surfaces on the androgen receptor (AR) and/or novel AR regulatory mechanisms are promising alternatives for the treatment of castrate-resistant prostate cancer. The 52 kDa FK506 binding protein (FKBP52) is an important positive regulator of AR in cellular and whole animal models and represents an attractive target for the treatment of prostate cancer. We used a modified receptor-mediated reporter assay in yeast to screen a diversified natural compound library for inhibitors of FKBP52-enhanced AR function. The lead compound, termed MJC13, inhibits AR function by preventing hormone-dependent dissociation of the Hsp90-FKBP52-AR complex, which results in less hormone-bound receptor in the nucleus. Assays in early and late stage human prostate cancer cells demonstrated that MJC13 inhibits AR-dependent gene expression and androgen-stimulated prostate cancer cell proliferation.

The anti-estrogenic activity of sediments from agriculturally intense watersheds: assessment using in vivo and in vitro assays.

The goal of the current study was to determine whether sediments from agriculturally intense watersheds can act as a potential source of anti-estrogenic endocrine-disrupting compounds. The specific objectives of the current study were to determine (1) whether female fathead minnows (Pimephales promelas) experience alterations in endocrine function when exposed to sediments collected from agriculturally intense watersheds and (2) if these sediments display anti-estrogenic activity in an in vitro assay. In addition, sediment samples were analyzed for the presence of steroid hormones and pesticides associated with local agricultural practices. To accomplish this, sediments and water were collected from three sites within two agriculturally intense Nebraska watersheds (Bow Creek and the Elkhorn River). In 2009, minnows were exposed to sediment and/or water collected from the two Bow Creek sites (East Bow Creek and the Confluence) in the laboratory, while in 2010, minnows were exposed to sediment and/or water from East Bow Creek, the Confluence and the Elkhorn River. Following the 7-day exposure period, the hepatic mRNA expression of two-estrogen responsive genes, estrogen receptor α (ERα) and vitellogenin (Vtg) was determined. In 2009, females exposed to Confluence sediments, in the presence of laboratory water or Confluence water, experienced significant reductions in ERα expression relative to unexposed and Confluence water-exposed females. The defeminization of these females suggests the presence of a biologically available anti-estrogenic compound in sediments collected from this site. In 2010, sediments were assessed for anti-estrogenic activity on days 0 and 7 of the exposure period using a 4-h yeast estrogen screen. Lipophilic extracts (LEs) of day 0 sediments collected from the Confluence and the Elkhorn River induced significant reductions in the estrogenic reporter activity of treated yeast cultures suggesting the presence of a lipophilic anti-estrogenic compound in these extracts. Chemical analysis revealed the presence of a variety of steroid hormones, including those associated with the production of beef cattle (i.e. ß-trenbolone, α-zearalanol and α-zearalenol), in sediments indicating that compounds utilized by local beef cattle operations are capable of entering nearby watersheds. Overall, the results of this study indicate that an environmentally relevant anti-estrogenic compound is present in sediments from agriculturally intense watersheds and that this compound is bioavailable to fish. Furthermore, the presence of steroid hormones in sediments from these watersheds provides evidence indicating that steroids are capable of sorbing to sediments.

A four-hour yeast bioassay for the direct measure of estrogenic activity in wastewater without sample extraction, concentration, or sterilization.

The assay described here represents an improved yeast bioassay that provides a rapid yet sensitive screening method for EDCs with very little hands-on time and without the need for sample preparation. Traditional receptor-mediated reporter assays in yeast were performed twelve to twenty four hours after ligand addition, used colorimetric substrates, and, in many cases, required high, non-physiological concentrations of ligand. With the advent of new chemiluminescent substrates a ligand-induced signal can be detected within thirty minutes using high picomolar to low nanomolar concentrations of estrogen. As a result of the sensitivity (EC(50) for estradiol is approximately 0.7nM) and the very short assay time (2-4h) environmental water samples can typically be assayed directly without sterilization, extraction, and concentration. Thus, these assays represent rapid and sensitive approaches for determining the presence of contaminants in environmental samples. As proof of principle, we directly assayed wastewater influent and effluent taken from a wastewater treatment plant in the El Paso, TX area for the presence of estrogenic activity. The data obtained in the four-hour yeast bioassay directly correlated with GC-mass spectrometry analysis of these same water samples.

Yeast-based reporter assays for the functional characterization of cochaperone interactions with steroid hormone receptors.

Steroid hormone receptor-mediated reporter assays in the budding yeast Saccharomyces cerevisiae have been an invaluable tool for the identification and functional characterization of steroid hormone receptor-associated chaperones and cochaperones. This chapter describes a hormone-inducible androgen receptor-mediated beta-galactosidase reporter assay in yeast. In addition, the immunophilin FKBP52 is used as a specific example of a receptor-associated cochaperone that acts as a positive regulator of receptor function. With the right combination of receptor and cochaperone expression plasmids, reporter plasmid, and ligand, the assay protocol described here could be used to functionally characterize a wide variety of nuclear receptor-cochaperone interactions. In addition to the functional characterization of receptor regulatory proteins, a modified version of this assay is currently being used to screen compound libraries for selective FKBP52 inhibitors that represent attractive therapeutic candidates for the treatment of steroid hormone receptor-associated diseases.