bluuebunny/crossref_metadata_2025 huggingface dataset:
GLP‐1‐producing Neurons in the Control of Glucose Homeostasis and Insulin Sensitivity
Authors: Shi Xuemei , Chacko Shaji , Li Depei , Li Feng , Guan Xinfu
Published: November 2023

Background and Objective

Glucagon‐like peptides (GLP‐1/2) are co‐released from enteroendocrine L cells in the gut and preproglucagon (PPG) neurons in the nucleus of the solitary tract (NTS) of the brainstem; and are key signals for the control of energy balance and glucose homeostasis. It is unknown if PPG neurons fine‐tunes central autonomic outputs to improve peripheral metabolism and insulin sensitivity. Our objective was to define if acute activation of PPG neurons enhances peripheral glycemic control and insulin sensitivity.

Methods and Results

1) Establishment of a pharmacogenetics mouse model for the remote control of activation of PPG neurons in vivo. First, we generated glucagon (Gcg) promoter‐driven Cre transgenic mouse line in which Gcg‐Cre expression was co‐localized to GLP‐1‐positive neurons in the brainstem. Second, we created a remote control of activation of PPG neurons in vivo mouse model using the DREADD approach. Cre‐dependent, excitatory AAV‐hM3Dq‐mCherry vectors were injected into the brainstem NTS of 8‐wk old Gcg‐Cre mice. 2) Validation of Gcg Cre‐dependent hM3Dq activation: The hM3Dq expression in the brainstem was validated using Gcg‐Cre::Rosa26‐eGFP reporter mice, in which hM3Dq‐mCherry was faithfully expressed in GFP‐positive neurons (identified by Gcg‐Cre‐mediated eGFP). Moreover, excitation of hM3Dq‐expressing neurons was confirmed by the whole‐cell patch clamp. Membrane potential and firing rate of Gcg‐Cre::hM3Dq‐mCherryNTS neurons were recorded in brains slices. 3) Central neural function of PPG neuronal activation: Activation of hM3Dq‐expressing neurons‐mediated neural circuitry was mapped by immuostaining c‐Fos in the brain after ip clozapine‐N‐oxide (CNO). Increased c‐fos expression was mainly localized to central autonomic regions. Moreover, PPG neurons‐mediated neurotransmitter profiling was quantified by LC‐MS/MS‐based metabolomics. As major neurotransmitters, GLP‐1/2 were released from activated PPG neurons. Upon CNO stimulus, the hM3Dq receptors rapidly activate infected PPG neurons in vivo. 4) Peripheral metabolic impact of PPG neuronal activation: With glucose tolerance test and hyperinsulinemic euglycemic clamp, glucose homeostasis and insulin sensitivity were quantified in conscious Gcg‐Cre mice injected with Cre‐dependent hM3Dq vectors. Fasting glucose was decreased while glucose tolerance was enhanced in the Gcg‐Cre mice after ip CNO. Glucose infusion rate was increased as resulted from augmentation of insulin‐mediated stimulation of glucose disposal and insulin‐mediated suppression of endogenous glucose production upon ip CNO.

Conclusions

Acute activation of PPG neurons in the brainstem NTS improves glucose tolerance and augments insulin sensitivity, suggesting that PPG neurons play an important physiological role in glycemic control and insulin sensitivity.

Support or Funding Information

The USDA CRIS grant 6250‐51000‐059 and the National NSFC grant 81570722.
The Role of Ankrd2 in Obesity‐Induced Inflammation and Insulin Resistance
Authors: Hernandez‐Carretero Angelina Marie , Weber Natalie , Doan Nhu Y Thi , Osborn Olivia
Published: November 2023

Obesity‐induced chronic inflammation is a key component in the pathogenesis of insulin resistance. Skeletal muscle is the major site of postprandial glucose uptake and in insulin resistance states, such as type 2 diabetes, insulin‐stimulated glucose disposal in skeletal muscle is markedly impaired. In this study we used RNA‐seq to discover differentially expressed genes between lean and obese/diabetic muscle that were also conserved across species in both mouse and human samples. We found that expression of ankyrin repeat domain protein 2 (Ankrd2) was reduced in both mouse and human muscle from obese/diabetic samples compared with control, lean muscle. We hypothesized that Ankrd2 contributes to muscle insulin sensitivity and that reduction of Ankrd2 may impair insulin‐stimulated glucose uptake. We used siRNA‐mediated knockdown of Ankrd2 in rat L6 myotube cells and performed glucose uptake assays. Preliminary results show that ~75% knockdown of Ankrd2 expression impairs insulin‐stimulated glucose uptake by 1.5‐fold. Furthermore, this knockdown of Ankrd2 led to changes in inflammatory gene expression. This study will determine whether Ankrd2 is a potential therapeutic target to enhance insulin sensitivity.

Support or Funding Information

A.H. is supported by National Institutes of Health IRACDA K12 GM068524 grant award
Epigenetic Regulation of Macrophage Polarization and Renal Inflammation
Authors: Pushpakumar Sathnur , Ren Lu , Biswas Raktim , Sen Utpal
Published: November 2023

Elevated level of homocysteine known as hyperhomocysteinemia (HHcy), is associated with hypertension and consistently reported in chronic kidney disease and occurs in >85% of patients suffering from end‐stage renal disease. HHcy can cause or potentiate renal injury by a variety of mechanisms including inflammation, oxidative stress, apoptosis and cellular proliferation. Recent studies suggest epigenetic factors may regulate some of these mechanisms. The purpose of this study was to investigate whether HHcy‐induced DNA methylation and histone modification causes macrophage polarization toward inflammatory M1 phenotype and thus persistent inflammation leading to progressive glomerular and microvascular injury. We also determined whether epigenetic inhibitor, 5‐Aza‐2′‐deoxycytidine (5‐Aza) will mitigate renal inflammation. Wild type (WT, C57BL/6J), and CBS+/− mice representing HHcy were treated without or with 5‐Aza. Control mice received saline. In vitro studies were done on RAW264.7 cells. Compared to WT groups, CBS+/− mice exhibited increased pro‐inflammatory mediators (TNFα, IL‐6) and chemokine expression (MCP‐1, CXCL2). Macrophage isolation and flow cytometry revealed increased expression of F4/80+/CD40+ cells suggesting M1 phenotype in CBS+/− mice compared to WT. Classically activated M1 macrophage was associated with hypomethylation of pro‐inflammatory mediators (TNFα, IL‐6) and hypermethylation of anti‐inflammatory mediators (IL‐4, IL10). 5‐Aza treatment in CBS+/−, mice resulted in reversal of methylation levels and reduction of inflammation. Measurement of iNOS/Arginase‐1 activity revealed increased M1/M2 ratio in hyperhomocysteinemia compared to normal homocysteine levels. 5‐Aza treatment decreased M1/M2 ratio suggesting increase in alternately activated M2 macrophage. The results above combined with mRNA and immunohistochemistry suggested persistent inflammation in the kidney during hyperhomocysteinemia.

Conclusion

Epigenetic alterations during HHcy promote macrophage polarization toward pro‐inflammatory response and therapeutic intervention with epigenetic inhibitor 5‐Aza has the potential to abrogate renal inflammation.

Support or Funding Information

AHA: 15SDG25840013NIH: HL104103
There is a greater ratio of Phox2B positive neurons to total neurons in the Nucleus of the Solitary Tract (NTS) than in the Dorsal Motor Nucleus of the Vagus (DMV)
Authors: Smith Madison , Martino Paul F. , Miller Justiin , Neumueller Suzanne , Hodges Matthew R. , Forster Hubert V.
Published: November 2023

Background

Congenital Central Hypoventilation Syndrome (CCHS) is characterized by severe apnea during sleep and dysfunctional chemosensitivity while awake. These patients exhibit a mutation in the 4p13 gene which codes for the Phox2b transcription factor. It has been established that the chemosensitive Retrotrapezoid Nucleus (RTN) is defined by Phox2b positive neurons on the ventral surface of the medulla which underlies the ventilator deficits for this syndrome. However, some patients also exhibit gastrointestinal and auditory complications, which are not related to the RTN. These neurons have yet to be defined in other areas of the brainstem for their specific functionality such as in the Nucleus of the Solitary Tract (NTS) and Dorsal nucleus of the vagus nerve (DMV). Discovering the functions of Phox2b+ neurons in other nuclei will help explain the other complications that can be expressed by the 4p13 gene mutation other than hypoventilation.

Method

To begin this process we defined whether there are Phox2b+ neurons in the NTS and DMV of goat subjects as well as the ratio of Phox2b+ neurons to total number of neurons in the NTS both caudal and rostral to obex. This was done through counting neurons in both a nissl and a Phox2b stain under a standard microscope.

Result

Thus far, we have found a significant number of Phox2b+ neurons from −1 to 3 mm in NTS and DMV. However, there is a lower ratio of Phox2b+ to total neurons within 1 millimeter both caudal and rostral from obex in the NTS, and from obex to 2 millimeters rostral in the DMV. The caudal portion of NTS has been known to be a site of central chemosensitivity, while the DMV is known to have gastrointestinal and respiratory functions.

Conclusion

Now that we have characterized the expression of Phox2b in the NTS and DMV, future studies will be aimed at determining their contribution to physiologic functions characterized in the NTS.

Support or Funding Information

Support: NIH HL25739 & Veterans Administration
The inwardly‐rectifying potassium channel subunit Kir5.1 contributes to acute and chronic pH homeostasis in rats
Authors: Hodges Matthew Robert , Puissant Madeleine Marie , Geurts Aron M.
Published: November 2023

The brain contains pH/CO2‐sensitive cells that may contribute to the acute regulation of pH through the ventilatory CO2 chemoreflex, including serotonergic neurons. However, molecular mechanisms by which these cells “sense” pH and or CO2 are not clear. We previously showed that inwardly‐rectifying potassium (Kir) subunit genes, Kcnj10 and Kcnj16 and their respective proteins (Kir4.1 and Kir5.1, respectively) increased in expression across development in serotonin (5‐HT) neuron‐enriched cell pools collected via flow cytometry. These Kir channel subunits combine with each other and other subunits to form pH sensitive K+ channels, and knockout of Kir5.1 in mice eliminates neuronal pH responses. Thus, we tested the hypotheses that in rats: 1) Kir5.1 channels were expressed in mature 5‐HT neurons, 2) that mutation of Kir5.1 channels would disrupt pH homeostasis and blunt the relationship between ventilation and pH/CO2. Kir4.1 and Kir5.1 immunoreactive (‐ir) cells were found throughout the brainstem, where all Kir4.1‐ir was co‐localized to glial cells (GFAP+). In contrast, Kir5.1‐ir cells were both glial and neuronal (NeuN+), where many 5‐HT (TPH+) neurons co‐localized with Kir5.1. We then measured breathing and blood gases in Kcnj16 mutant rats, in which a 18 base pair deletion was created in exon 1 of the Kcnj16 gene in Dahl S (SS) rats (SS‐Kcnj16em1Mcwi rats). SS‐Kcnj16em1Mcwi rats were smaller in size (~40%) but did not show increased mortality after weaning. SS‐Kcnj16em1Mcwi rats had Kir5.1‐ir cells throughout the CNS, indicating the mutation was not a null mutation. SS‐Kcnj16em1Mcwi rats were in chronic metabolic acidosis (pH ~7.32) at rest breathing room air, which was partially compensated as ventilation was increased (via increased tidal volume) and arterial PCO2 was decreased compared to naïve SS rats (P<0.05). Paradoxically, SS‐Kcnj16em1Mcwi rats showed a blunted relationship between ventilation and arterial PCO2 and pH when environmental CO2 was increased to 3, 5, 7 or 9% CO2. In control SS rats, ventilation increased 528.5 ± 58.4 ml/min for every decrease of 0.1 of pH units, compared to 300.8 ± 51.2 ml/min/0.1 pH unit in SS‐Kcnj16em1Mcwi rats. Similarly, ventilation increased 40.4 ml/min/mmHg and 25.8 ± 2.9 ml/min/mmHg in control and SS‐Kcnj16em1Mcwi rats, respectively. These data suggest that pH sensitive Kir5.1‐containing channels may contribute to glial and (5‐HT) neuronal pH sensitivity in rats, and that Kir5.1 channels contribute to acute and chronic regulation of pH homeostasis.

Support or Funding Information

NIH HL122358 and HL112996
How Inhibition of CO2/H+‐sensitive Ionic Currents affects the Firing Rate of a Single‐Neuron Model of Central Chemoreceptors?
Authors: Quintero Maria Carolina , Cordovez Juan Manuel , Putnam Robert
Published: November 2023

An increase in CO2/H+ is a major stimulus for increased ventilation and is sensed by central chemoreceptor neurons in various nuclei of the brainstem. Of particular importance in the study of central chemoreception are the cellular factors that determine the increased firing rate response of these neurons to acidotic conditions. A multiple factors model proposes that a set of signals and ion channel targets results in the increased firing rate response when chemoreceptors are stimulated with hypercapnic acidosis. We have developed a mathematical model for a mammalian chemoreceptor to understand the interplay between the underlying pH‐sensitive ionic currents when stimulated with increased CO2/H+. It consists of an ionic membrane model of the Hodgkin‐Huxley type with several CO2/H+‐sensitive currents that makes the neuron fire at frequencies between 0.4 and 4 Hz. The currents included in the model are: fast Na+, delayed rectifier K+, inward rectifier K+, TASK, A‐type K+, L‐type Ca2+, BK‐type Ca2+‐activated K+, and a hyperpolarization activated current. We also included a background current to take account of ion flows driven by pumps and regulatory mechanisms that are not represented as independent currents in the model. We performed a sensitivity analysis for the pH‐sensitive currents to study the effect of their conductance on the firing frequency of the neuron and to determine which currents are playing the major role in the chemosensitive response. For each current, a sensitivity factor was calculated as the rate of change of the firing frequency with regard to conductance in normocapnic conditions. The analysis revealed a higher sensitivity for TASK, L‐type Ca2+, and background currents, with sensitivity values between −3.3 and −1.5, compared with other currents with sensitivity absolute values below 0.05. These results indicate that a small inhibition of these currents results in a significant increase in the firing rate of the neuron compared with other channels, which would result in an increased chemosensitive response with the appropriate stimulus. These findings support the multiple factors model of chemosensitive signaling and postulate TASK and Ca2+ currents as primary sensors. We also highlight the contribution of unknown mechanisms like acid sensitive pumps and pH regulatory mechanisms, which might be responsible for the unexpectedly high sensitivity of the background current in this model.
Activation of Bitter Taste Receptors in Rat Pulmonary Sensory Neurons Augments Capsaicin‐Evoked TRPV1 Responses
Authors: Gu Qihai , Joe Deanna , Gilbert Carolyn , Gabriel Sabry
Published: November 2023

Bitter taste receptors (T2Rs), a G‐protein‐coupled receptor family capable of detecting hundreds of bitter‐tasting compounds, have recently been shown to be expressed and play diverse roles in various extraoral tissues. Here we report the functional expression of T2Rs in rat pulmonary sensory neurons. In anesthetized spontaneously breathing rats, intratracheal instillation of T2Rs agonist chloroquine (10 mM, 0.1 ml) significantly augmented the chemoreflex responses evoked by right‐atrial injection of capsaicin, a specific activator for transient receptor potential vanilloid receptor 1 (TRPV1); whereas intravenous infusion of chloroquine failed to significantly affect capsaicin‐evoked reflexes. In patch‐clamp recordings with isolated rat vagal pulmonary sensory neurons, pretreatment with chloroquine (1–1000 μM, 90 s) concentration‐dependently potentiated capsaicin‐induced inward currents. This sensitizing effect of chloroquine was effectively blocked by phospholipase C inhibitor U73122 (0.75 μM), or by protein kinase C inhibitor chelerythrine (5 μM). In summary, our study showed that activation of T2Rs augments capsaicin‐evoked TRPV1 responses in rat pulmonary sensory neurons, through phospholipase C and protein kinase C signaling pathway.

Support or Funding Information

Supported by funds from MEDCEN and MUSM.
Blocking Volume Regulated Anion Channels (VRAC) with DCPIB Depresses Avian Intrapulmonary Chemoreceptor (IPC) Discharge more in Tonic than Phasic Units
Authors: Molloy Rhett Gordon , Bassett Peter Ross , Lonjaret Jean‐Guillaume , Burchinal Krystal L , Hempleman Steven Curtis
Published: November 2023

Intrapulmonary chemoreceptors (IPC) are respiratory vagal afferents that sense PCO2 changes and are responsible for controlling breathing in birds. Volume regulated anion channels (VRAC) are responsible for volume regulation in a large variety of cell types. Small doses of DCPIB (1 to 8 μmol/kg), a specific blocker of VRAC, were used to test for VRAC presence in IPC of pentobarbital‐anesthetized ducks (Anas platyrhyncos, n=11). Cycle triggered stimulus histograms of IPC action potential discharge to 0%–7% inspired CO2 steps were recorded and separated into 2 groups according to their spike frequency adaptation: phasic (n=4), tonic (n=7). The IPC discharge for phasic units remained unchanged from the control for the 1 to 4 μmol/kg doses, while the 8 μmol/kg dose reduced the peak phasic adaptation (ANOVA, p<0.01). Tonic units progressively reduced discharge for all doses (ANOVA, p<0.01). Since DCPIB more strongly affects IPC discharge in tonic units compared to phasic units the results suggest that: 1. Tonic and phasic units may have different mechanisms for VRAC activation, or 2. Tonic units express more VRAC than phasic units.

Support or Funding Information

Support: NIH R15 HL087269‐02.
The Testing Effect Varies with Spaced Versus Massed Learning of Skeletal Muscle Information
Authors: Dobson John , Perez Jose
Published: November 2023

Learners who engage in testing or effortful retrieval throughout learning tend to retain more following a delay compared to those who read and reread to‐be‐learned materials. Additionally, studying sessions that are spaced apart by one or more days tend to promote more recall than do those that are massed together at the same time. Although both the testing and spacing effects are well‐established in the cognitive psychology literature, no studies have examined their additive effect with anatomy and physiology information. The purpose of this study was to determine if the benefits of a testing‐based strategy vary with massed versus spaced learning sessions. Participants used the following strategies to learn sets of human skeletal muscle information: 1. reading‐rereading on three different days (RRRRx3), 2. reading‐testing on three different days (RTRTx3), 3. reading‐rereading on two different days (RRRRRRx2), 4. reading‐testing on two different days (RTRTRTx2) and 5. reading‐testing on a single day (RT6x1). The five strategies were standardized so that participants used each for a total of exactly twenty four minutes. The retention of muscle information was assessed via free recall. One week after learning, the assessment scores were 24.10 ± 3.08, 33.74 ± 3.43, 15.47 ± 2.44, 20.56 ± 2.89 and 12.76 ± 2.02 for the RRRRx3, RTRTx3, RRRRRRx2, RTRTRTx2 and RT6x1 strategies, respectively. In conclusion, the more spaced strategies produced better recall than the less spaced strategies, the testing‐based strategies produced better recall than reading‐only strategies, and the combination of spacing and testing generated the greatest recall of muscle information.

Support or Funding Information

None
How do we train our future faculty to teach? Results from a multidisciplinary comparison of pedagogy courses offered at a large midwestern university
Authors: O'Loughlin Valerie Dean , Kearns Katherine D , Robinson Jennifer Meta , Sherwood‐Laughlin Catherine
Published: November 2023

Much effort is devoted to training graduate students (a.k.a. future faculty) to perform research; less attention is paid to their development as teachers. Previous research has demonstrated that pedagogy courses help support the developmental progression of graduate students. These courses allow the student to develop and reflect on teaching experience, and progress from excellent teachers to teacher‐scholars (individuals who practice scholarly teaching). This previous research typically has focused on single pedagogy courses, where findings may be context‐specific and sample sizes (i.e., student enrollment) typically is small.

Our research is the result of a metacollaboration among individuals with prior experience in studying the effects of individual pedagogy courses. Here, we focus on examining multiple (over 30) discipline‐specific and interdisciplinary graduate pedagogy courses offered at Indiana University, a large midwestern research‐intensive university. By comparing and pooling data from multiple courses, we have been able to substantially increase sample sizes and generalize our research findings about teacher‐scholar development. Faculty who teach pedagogy courses were invited to complete an online survey and provide the researchers with the syllabi from their courses for analysis of how these courses help graduate students a) develop into teacher‐scholars and b) express their teaching identity through a teaching statement.

Survey results indicated that multiple disciplines across the university offer graduate pedagogy courses. These courses typically are 3‐credit hour semester courses, although some courses are offered as intensive summer sessions or as 8 week courses. Enrollment means range from 8–15 students for most courses. Over 3/4 of these courses introduce students to the concept of a teaching statement, and the majority of these courses require students to complete a teaching statement as part of the course. Additional data and comparisons will be presented at the meetings, and the implications for graduate student teacher‐scholar development will be discussed.

Support or Funding Information

This research was funded, in part, by a 2015 Indiana University SoTL (Scholarship of Teaching and Learning) grant
Measurement Theory and the P‐matrix: Ramifications of Variable Choice
Authors: Savell Kristen R. R. , Auerbach Benjamin M.
Published: November 2023

Choosing which measurements to include in an analysis is often as much a matter of tradition and training as critical evaluation. Variable choice, however, may have unintended consequences on conclusions, especially in studies that assume these variables reflect evolutionary and developmental processes. Such studies include quantitative genetic analyses that use phenotypic variance‐covariance matrices (P‐matrices) as an estimation of genotypic variance‐covariance. P‐matrices are assumed to be proportional to G‐matrices within a population, and therefore serve as proxies for interpreting evolutionary change. However, since the multivariate space of a P‐matrix will change with the addition or subtraction of variables, P‐matrices may be limited by the biases associated with variable choice. For example, what is the range of possible variation observed in the P‐matrices of a single skeletal element within the same taxa, and how can this variance inform our understanding of P‐matrix construction?

To study the ramifications of variable choice in the construction of P‐matrices, linear measurements (representing a range of genetic, developmental, and activity‐based morphologies) were taken from the tibiae of 60 tamarins (Saguinus). These dimensions were mean‐scaled to remove the effects of trait size magnitude. Individuals from three subspecies (S. oedipus, S.f. illigeri, S. f. nigrifrons) were pooled, as random skewer analysis indicated no significant differences between their sub‐specific P‐matrices. This pooled P‐matrix was created of all six measurements then subjected to randomly‐generated selection gradients to allow for comparison between responses (following Lande). The influence of matrix construction was evaluated by calculating cosine‐similarities between the response vectors of the complete P‐matrix and P‐matrices that had either one measurement or a pair of related measurements (lengths, diaphyseal diameters, or epiphyseal widths) removed. Results indicate that, regardless of selection gradient, tibial length provides nearly all of information included in the complete P‐matrix response. Similarly, the removal of other measurements did not substantially alter the response vector. In fact, the role of non‐length measurements was so low and the correlation between the two length measurements so high, the same amount of explanatory information was contained within a single variable of length as in the complete variance‐covariance matrix.

Though this relationship may be unsurprising on a biological level, it demonstrates the importance of variable choice in the creation of a P‐matrix. Ultimately, quantitative genetic analyses of this variety rely on understanding the structure and apportionment of variance, and so traits that explain most of the variance will swamp the explanatory power of other traits that may be evolutionarily informative. Care must therefore be taken in selecting traits to include in evolutionary studies using P‐matrices.
Surgery to Relieve Thoracic Outlet Syndrome Complaints Should Have Preoperative Imaging:MRI/MRA/MRV
Authors: Collins James Douglas , Saxton Ernestina Howell , Gelabert Hugh Anthony , Carnes Alfred
Published: November 2023

INTRODUCTION

Thoracic Outlet Syndrome (TOS) patients are normally managed conservatively with physical therapy (PT) and may undergo scalenectomy and first rib resection without imaging. Bilateral multiplanar magnetic resonance imaging and 2D time of flight magnetic resonance angiography and venography (MRA/MRV) of the brachial plexus display costoclavicular compression of the draining veins within the neck, supraclavicular fossae, and neurovascular bundles as the diagnostic cause of thoracic outlet syndrome.

METHODS

Bilateral MRI/MRA/MRV displays sites of obstruction of the draining veins of the neck and the subclavian and axillary arteries with binding nerve roots. Monitored multiplanar images are acquired on a 1.5 Tesla GE Signa LX unit, 44 cm field of view, 512 × 256 matrix with saline water bags to enhance signal to noise ratio.

The case selected for this presentation was diagnosed with left TOS and left pectoralis minor syndrome. Her surgeon convinced her that there was no need for imaging. However, she developed postoperative complaints and sought evaluation by a neurologist. Thereafter, bilateral imaging of the brachial plexus was requested displaying the surgical alteration of landmark anatomy, costoclavicular compression of binding nerves to the subclavian and axillary arteries, obstruction to venous drainage, scarring and fibrosis from the resected lymphatics marginating veins within the pectoralis minor muscle adhering the pectoralis major muscle to the anterior chest wall.

CONCLUSION

Nerves, arteries, veins and lymphatics are within the fascial planes marginating muscles. Health professionals should be aware that resection of the pectoralis minor muscle tendon (tenotomy) at the coracoid process disrupts lymph drainage precipitating fibrosis and scarring of those structures within. Baseline plain radiographs and MRI of the brachial plexus should be obtained prior to all surgical intervention.
The Use of “Structured Lab Review” to Augment Student Learning and Its’ Impact on Cadaveric Practical Examination Performance
Authors: Vasan Cheryl , Gentile Mathew , Vasan Nagaswami
Published: November 2023

In an integrated organ systems‐based preclinical curriculum time for cadaveric dissection and learning from it is becoming a challenge due to reduced curricular hours for delivery of anatomy content. This poses a challenge in which judicial planning is essential in determining how to maximize the available time to benefit student learning. At Cooper Medical School of Rowan University, we faced such a challenge in our Skin and Musculoskeletal (SMS) course during the 2013/2014 academic year that resulted in poorer student exam performance. While students performed satisfactorily on anatomy specific content in the written exam, their performance in the cadaver based practical exam suffered. The cadaver oriented exam required students to identify a tagged structure and answer a primary, secondary, or tertiary question related to the tagged structure. We realized that students were able to identify structures on their cadaver, but not on their fellow classmate's cadavers as they spent very little time in reviewing cadavers other than their own. This resulted in a lack of familiarity, on the part of the students, with regards to structures on the other cadavers. This presented a challenge as to how to improve student recognition of structures across cadavers, as well as it created an opportunity to institute Structured Lab Review sessions within the 2015 SMS course. The Structured Lab Review required students to rotate as a dissection team through all the cadavers, identify several structures from a list provided at each cadaver, answer secondary and tertiary questions about the structures, as well as engage in peer‐to‐peer teaching when group members required help in answering a question(s). We found that students performed significantly better in the 2015 SMS practical exams when compared to the 2014 exams. In addition, students were very satisfied with the Structured Lab Review sessions. This poster will provide the details of planning and executing a Structured Lab Review session as well as provide examples of questions used. Analysis of student performance will be presented. Furthermore, we have since instituted “Structured Lab Review” sessions in the other system‐based modules for academic year 2015/2016.

Support or Funding Information

This study was supported by the Department of Biomedical Sciences.
How the distinctive cultures of osteopathic and allopathic medical schools affect the careers, perceptions, and institutional efforts of their anatomy faculties: A qualitative case study of two schools
Authors: Byram Jessica , Traser Courtney , Arbor Tafline , Brokaw James
Published: November 2023

Recent years have witnessed major curricular changes that pose significant challenges to anatomy faculty members’ job satisfaction and sense of autonomy at both allopathic and osteopathic medical institutions. This case study examined anatomy faculty perceptions at two philosophically distinct medical schools to assess how different institutional characteristics and curricular change have impacted anatomy faculty members’ teaching responsibilities and research, as well as their sense of autonomy and overall career satisfaction. Semi‐structured interviews of teaching‐ and research‐focused anatomy faculty from a large, well‐established allopathic medical school (Indiana University School of Medicine, n = 5) and a small, new osteopathic medical school (Marian University College of Osteopathic Medicine, n = 4) were explored using qualitative thematic analysis. The results demonstrated that anatomists teaching at allopathic and osteopathic medical schools had more similarities than differences, particularly in their commitment to teaching. Most of the differences between the two faculties were unrelated to the philosophical orientation of the institution (i.e., allopathy vs. osteopathy). Rather, differences were predominately shaped by the size and history of the institution, the school's promotion and tenure guidelines, and the perceived degree of faculty autonomy. Furthermore, the anatomists’ personal educational philosophies and research agendas had a greater impact on their global satisfaction and instructional strategies than did the philosophical orientation of their institution. These findings accentuate the similarities amongst anatomy faculty members at allopathic and osteopathic institutions. We advocate for a sharing of educational resources and research collaborations to improve anatomy education and faculty development between institutions.
Seeing is Knowing: Instructor Perceptions of Teaching an Online Undergraduate Anatomy Course with Laboratory
Authors: Attardi Stefanie M , Mintz Noah M , Barnett John , Rogers Kem A
Published: November 2023

Online versions of traditional face‐to‐face (F2F) courses at post‐secondary institutions have become prevalent due to increased enrollment in undergraduate programs. While many studies assess the impact of online delivery formats on student outcomes, fewer examine how teaching online affects instructors. An online section of a traditional F2F undergraduate anatomy course with a prosection laboratory commenced in 2012–13 at Western University Canada. Lectures for F2F students were broadcast in both live and archived format to online students using Blackboard Collaborate virtual classroom software (BBC). Laboratories were delivered online by a teaching assistant (TA) who manipulated 3‐dimensional (3D) anatomical computer models in BBC. The objectives of this study were to reveal instructor perceptions of teaching online and suggest modifications for future years. Online instructors (4 professors; 5 TAs) who taught during the first two course offerings participated in individual open‐ended interviews. Emergent themes were generated from a content analysis of interview transcripts (2 independent coders; Fleiss’ kappa = 0.82). The major emergent theme encompassed issues pertaining to teaching without seeing the learner. The instructors were unable to use non‐verbal student feedback (e.g body language) during a lesson to assess engagement (N = 8) and understanding (N = 4). The instructors identified additional methods of communication (email, instant messaging and drawing in BBC) to be sufficient when initiated by students (N = 6). The impact of BBC use on teaching practices was also discussed. Preparation time for teaching online was longer than for F2F, although the difference was not substantial (N=7). Though BBC was reliable and easy to use for lecture broadcasts, all professors noted that it impeded their mobility in the lecture hall, thus it was perceived that interaction with the F2F students decreased. In the online laboratory, live desktop sharing of 3D models in BBC was not possible due to the quality of students’ internet connection speeds; however, the majority of TAs (N = 3) found pedagogical value in the students drawing on screen captures of 3D models to communicate understanding. In the future, mandatory synchronous participation through instant messaging may improve feedback to instructors on student engagement and understanding, though it might not be feasible due to schedule conflicts. It is recommended that online instructors organize frequent formative student assessments to obtain feedback on engagement and understanding.
Using Ultrasound To Assess Accuracy Of Liver Measurement And Palpation During Early Medical Training
Authors: Brower Gregory L. , Tipton Valerie , Kim Jongyeol , Lee Vaughan H. , Prabhu Fiona R.
Published: November 2023

The changing nature of medicine requires the innovative use of new techniques and technologies in medical education. A specific learning objective in our Development of Clinical Skills (DOCS) course is that students develop proficiency in palpation of subcutaneous structures when performing physical examinations. Abdominal examination is a challenging skill for Year 1 medical students to master. Evaluation of the abdominal system with respect to the liver typically includes percussion, palpation and/or the scratch test to determine localization of the liver edge and measurement of liver span. Historically it has been difficult to assess the student's proficiency in performing this aspect of the physical examination. Moreover, studies show that clinicians routinely underestimate the liver span as compared to that measured by ultrasonography. Thus, more effective methods to enhance learning of abdominal examination techniques are needed. Accordingly, we have developed and evaluated an approach to teaching examination of the liver that incorporates real‐time ultrasound imaging to provide immediate feedback to improve diagnostic accuracy. The dimension of liver span and location of the liver edge along the right midclavicular line were first determined by percussion and palpation in a standardized patient. Students were not initially given feedback as to the accuracy of their perceived liver edge localization. The accuracy of the student's estimated measurement was then compared to the exact dimension of liver span and the edge visualized using ultrasound imaging (GE LOGIQ ultrasound using a 4C probe). A distinct advantage of utilizing this approach is the student can develop their palpation skills based on immediate feedback, thus improving their accuracy for times when ultrasound is not available. We found ultrasound‐assisted determination of liver edge localization and span to be a useful adjunct to traditional means of teaching abdominal examination skills resulting in improved student physical examination technique. Finally, it provides our students with a solid foundation in point‐of‐care ultrasonography.
Individualized Learning in Anatomy to Diversify Tomorrow's Medical Field
Authors: Gong Jing Jing , Schindel Benjamin , Jerome Christopher , Antoine Kevin L. , Pagano Anthony S. , Márquez Samuel
Published: November 2023

In public school classrooms, the large‐class format encourages the majority to dictate learning pace, often to the detriment of individual progress. This problem is especially pressing among “minority” groups that have been “historically underrepresented in medicine relative to their numbers in the general population” (as defined by the American Association of Medical Colleges – AAMC). Downstate Health Professions Recruitment and Exposure Program (HPREP) annually invites 36 Brooklyn high school students from minority groups to attend physiology lectures, conduct anatomical dissections, and learn clinical skills from medical students. To quantify student learning, five‐question pre‐ and post‐test evaluations are conducted at each session. Results showed a statistically significant difference in pre‐ and post‐test assessment (P < 0.02) for the first session of our program, which is comparable to the P‐values of all session activities from last year. The key to the outreach program stems from HPREP's individualized curriculum approach and using anatomy to fuel the high school students’ passion for medicine. The low student‐to‐mentor ratio of 2:1 encourages students to ask questions, explore the scientific method in a hands‐on approach, and gain confidence in their academic abilities. The Assistant Vice President of the Office of Diversity & Inclusion at SUNY Downstate supports this student‐driven education outreach program because it will have an immediate impact on our community by initiating excitement, cultivating enthusiasm, and promoting the exposure of our young underrepresented students to medical career options. While the long‐term effects cannot be immediately measured, fostering this early interest in medicine and familiarity with the essential discipline of anatomy is a critical first step to ensuring greater diversity among healthcare professionals.
Proteomic analysis of a meiotic recombination hotspot
Authors: Storey Aaron J , Protacio Reine U , Tackett Alan J , Davidson Mari K , Wahls Wayne P
Published: November 2023

Meiotic recombination promotes genetic diversity within species and is essential for accurate segregation of homologous chromosomes in meiosis I. Hotspots regulate the frequency and distribution of recombination in the genome. DNA binding proteins and post‐translational modifications (PTMs) of histones help to regulate hotspots by recruiting the basal recombination machinery (e.g., Spo11/Rec12), but few of the ~400 known histone PTMs have even been interrogated for a potential role in recombination. Here, we developed a mass spectrometry‐based approach for the unbiased, systematic discovery of hotspot‐specific (potentially regulatory) proteins and histone PTMs using the well‐characterized, DNA sequence‐dependent hotspot ade6‐M26 of fission yeast. We constructed small (4.2 kbp) minichromosomes (MiniCs) harboring hotspot and negative control alleles. Chromatin immunoprecipitation (ChIP) of recombination‐initiating dsDNA breaks revealed that the hotspot is active in MiniCs. MiniCs were purified from meiotic cultures using the high‐affinity interaction between LacO DNA sites in the MiniCs and a prA‐LacI fusion protein conjugated to beads. Enrichment levels of 20,000‐fold (relative to single copy loci) were routinely observed by gel electrophoresis and quantitative PCR. Mass spectrometry of the MiniCs identified 1023 proteins, 71 of which were enriched specifically in the hotspot sample. Fifteen different histone PTMs were identified, along with 7 histone modifying enzymes and 37 recombination‐related proteins. The DNA repair proteins Dmc1 and Rad50 were highly enriched in the hotspot sample, further validating the sensitivity and accuracy of this approach. We are currently implementing isobaric mass tag strategies using the latest generation of mass spectrometry instruments for more powerful quantitation of resulting proteomic datasets, and we are validating the biological functions of newly discovered hotspot factors.

Support or Funding Information

National Institute of General Medical Sciences (R01 GM081766)
Complex Roles of ADAM Cell Surface Metalloproteases During Cranial Neural Crest Cell Migration
Authors: Alfandari Dominique , Abbruzzese Genevieve , Mathavan Ketan , Cousin Helene
Published: November 2023

Objective/Background

ADAMs are cell surface metalloproteases that shed a variety of substrate from the plasma membrane and contribute to multiple signaling cascades. Our objective was to determine the role of this protease during cranial neural crest cell migration.

Methods

We have used replacement of the endogenous ADAM proteins with proteins encoding truncated and mutated forms to test their ability to promote neural crest cell migration. Migration was assessed by following fluorescently labeled cells in vivo and in vitro.

Results

We found that meltrins (ADAM9, 13 and 19) play a complex role to promote cranial neural crest cell migration. ADAM9 and 13 cleave Cadherin‐11 to release an extracellular fragment that promotes cell migration by signaling via receptor tyrosine kinases. In addition ADAM13 cleaves multiple protocadherins and extracellular matrix proteins that may contribute to its activity during CNC migration. Finally, the cytoplasmic domain of ADAM13 undergoes multiple phosphorylation and cleavage that result in its translocation into the nucleus where it regulates the expression of multiple genes including cytoplasmic (calpain8) and extracellular proteases (MMP13).

Conclusions

While the proteolytic activity of ADAM is certainly critical as confirmed by our study, our result also uncovered an independent role for the cytoplasmic domains that has been conserved during evolution.

Support or Funding Information

NIH RO1‐DE016289, NIH F31‐DE023275
Deletion of five senescence‐associated lncRNAs in Saccharomyces cerevisiae
Authors: Krauss Katarzyna , McMurdie Karen , Zappulla David
Published: November 2023

Telomerase is a ribonucleoprotein composed of a long noncoding RNA (lncRNA), reverse transcriptase, and associated proteins. This enzyme is responsible for maintaining telomere length, and when it is inactive, as in most somatic cells, telomeres gradually shorten, leading to aging and aging‐related illnesses. In contrast, telomerase activity is high in approximately 90% of cancers, allowing for the cells to continuously divide. To better understand the cellular mechanisms surrounding senescence and determine the role that lncRNAs have in this process, RNA sequencing was performed on a strain of Saccharomyces cerevisiae that lacked functional telomerase both during and after senescence, resulting in the identification of 112 novel senescence‐associated lncRNAs. Five of these lncRNAs were further characterized because they were highly conserved among yeast species and appeared to be independently transcribed. Each lncRNA was knocked out in both a diploid and haploid yeast strain, creating ten novel strains. The budding yeast strains were tested at varying temperatures and in the presence of caffeine, which is known to cause telomere shortening, to search for phenotypic responses in these conditions. Future research in this area and in a wider variety of conditions could increase understanding of lncRNAs associated with aging and senescence.

Support or Funding Information

Funding for this project was provided by the National Science Foundation REU site award DBI‐1262985
Non‐Coding RNA Regulations in Pseudomonas aeruginosa
Authors: Ammons Mary Cloud B
Published: November 2023

Bacterial biofilms are the major bioburden contributing to pathogenesis in chronic wounds such as diabetic foot ulcers, pressure ulcers, and veins leg ulcers. Mechanisms of biofilm formation are still under intense investigation and targets of precision therapeutics. Virulence and quorum sensing genes are increasingly appreciated as transcriptionally directed by non‐coding RNAs. Typically associated with eukaryotic regulation, bacterial have recently been appreciated as utilizing ncRNAs for gene and post‐transcriptional regulation. Using a RNseq and bioinformatic approach, we demonstrate significant utilization of ncRNAs in the biofilm phenotype when compared to planktonic cultures in Pseudomonas aeruginosa PAO1 biofilms. Through this analysis and network analysis, we confirm recently identified ncRNA regulation of quorum sensing and virulence factors, was well as identify novel ncRNAs associated with biofilm formation. Specifically, we find ncRNA regulation associated with the metabolic phenotype of P. aeruginosa PAO1 biofilms and confirm the transcriptional regulation of this phenotype through 1H NMR metabolomics profiling.

Support or Funding Information

5K01GM103821‐04

1R03AR060995‐01

16‐746Q‐MSU‐PG51‐00, a pilot and feasibility award of parent grant 5U54GM104944‐03
Post‐transcriptional Modifications Alter Anticodon Loop Dynamics and Codon Recognition in E. coli tRNAArg1,2
Authors: Sarachan Kathryn Lorenz , Cantara William A. , Vangaveti Sweta , Spears Jessica L. , DeMirci Hasan , Murphy Frank V. , Ranganathan Srivathsan V. , Agris Paul F.
Published: November 2023

In Escherichia coli, three of six arginine codons (CGU, CGC and CGA) are decoded by only two tRNAArg isoacceptors. The anticodon‐stem loop (ASL) domains of tRNAArg1 and tRNAArg2 differ only at position 32: tRNAArg1 is post‐transcriptionally modified to contain a 2‐thiocytidine (s2C32), while the same cytidine in tRNAArg2 is unmodified. Both isoacceptors also contain naturally‐occurring modifications at positions 34 (inosine, I34) and 37 (2‐methyladenosine, m2A37). To investigate the functional roles of these modifications, six ASL constructs, differing in their array of modifications, were analyzed using binding studies and structural and computational methods. Ribosome filter binding assays showed that while I34, as expected, facilitates wobble codon binding, both s2C32 and m2A37 modulated that effect by negating binding to the rare CGA codon. When a non‐naturally occurring s2C32 was introduced for C32 in an unrelated S. cerevisiae tRNA ASLIle construct also containing C32 and I34 and capable of wobble pairing, the same functional restriction of CGA binding was observed. The NMR and x‐ray crystallographic structures of the ASLs failed to offer an explanation for this effect and showed only minor anticodon loop perturbation upon inclusion of s2C32. The mechanism by which the modification affects codon binding was then investigated by molecular dynamics simulations. Using free‐‐energy perturbation calculations, s2C32 was shown to destabilize the anticodon stem loop in solution; a free energy penalty was demonstrated to exist for the introduction of s2C32 in ribosome‐bound tRNA, explaining the reduction in binding observed experimentally. Simulation and experimental results are consistent and provide a platform for gaining insights into the modulation of tRNA function by post‐transcriptional modifications.