bluuebunny/crossref_metadata_2025 huggingface dataset:
BK channel differences in near‐term fetal and adult ovine small pulmonary arteries
Authors: Hessinger David A , Thorington Glyne U , Sokolova Irina , Fletcher William H , Pretorius Miles R , Morris Daniel P , Longo Lawrence D
Published: November 2023

Pulmonary vasodilatation at birth underlies the fetal transition to lung breathing. Failure to vasodilate causes persistent pulmonary hypertension of newborn, persistent patency of the ductus arteriosus and foramen ovale, and bronchopulmonary dysplasia‐related hypoxia, often with dire consequences. The mechanism of pulmonary vasodilatation at birth is poorly understood. Pulmonary artery smooth muscle cells (PASMCs) isolated from 4th and 5th order resistance vessels of ovine near‐term fetus exhibited resting membrane potentials 8 mV more depolarized than adult (P<0.05), consistent with vasoconstriction. Whole‐cell Kv current densities for voltage‐clamped fetal and adult PASMCs were similar. In contrast, large‐conductance, calcium‐activated K+ (BK) channel current densities for fetal cells were significantly lower than adult at +20 to +60 mV, but equal to adult at higher potentials. By Western immunoblots, fetal PASMCs expressed twice the pore‐forming BKα subunit protein as adult, but only half as much accessary BKβ□ subunit. By flow cytometry, cell surface βl expression was also significantly lower in fetal PASMCs. Since optimal BK channel activity occurs at 1:1 β‐to‐α stoichiometry, our results suggested the near‐term fetus expressed BK β:α ratios about ¼ that of adult. These findings suggest near‐term fetal PASMCs are more depolarized than adult due to lower BK activity and lower BKβ□ subunit expression. In agreement with BKα protein levels, BKα mRNA levels were two‐fold higher in near‐term fetus than in adult by qRT‐PCR. However, in contrast to BKβ□ protein levels, BKβ□ mRNA levels were two‐fold higher in near‐term fetus than adult. These findings suggest that BKβ□ mRNA levels may be poised to express higher levels of BKβ□ protein at birth in order to enhance BK channel activity and promote pulmonary vasodilatation upon transition to lung breathing.

Support or Funding Information

National Institutes of Health Grants HD‐003807‐41 and HD031226‐20 (to LDL)
Developing Online Guided Self‐assessments in Cardiovascular Physiology for Medical School
Authors: Pressley Thomas A. , Fowler John C.
Published: November 2023

Preclinical medical students have access to numerous question banks and books that provide examples of NBME‐style questions for use in USMLE Step 1 preparation. However, many of these questions are beyond the scope of first‐year medical physiology and are of limited utility when preparing for exams. Accordingly, many course directors and faculty members develop their own questions that are used by students for self‐assessment. In this study, we developed self‐assessment questions about cardiovascular physiology that could be delivered online and provided specific feedback to students in response to both correct and incorrect responses. We used Microsoft PowerPoint to create a series of multiple choice questions. Incorrect responses were linked to subsequent slides that attempted to correct misunderstandings or errors that might have contributed to the wrong choice. Correct responses were linked to slides that provided encouragement and reinforced the critical concept. The slides for both incorrect and correct responses offered links to slides containing short reviews of the relevant concepts. Once the PowerPoints were reviewed by colleagues and revised, iSpring Presenter was used to create online learning “packages” that could be posted on our course management system. These packages offered two advantages. First, they could be created in multiple formats that were compatible with most computers and tablets. Second, they prevented a student from circumventing the question‐response sequence via download of the original PowerPoint file. After developing four 10‐question self‐assessments covering various cardiovascular concepts, we compared students’ utilization statistics with those for four traditional sets of example questions on renal physiology. In the first year of their introduction, the online self‐assessment packages were used nearly twice as often. Our data suggest that such online guided self‐assessments are a popular mechanism for student learning that should be explored further.

Support or Funding Information

Supported by departmental and institutional funds.
The Prevalence of Exercise Prescription‐related Course Offerings in U.S. Pharmacy School Curricula: Exercise is Medicine®
Authors: Dirks‐Naylor Amie J , Griffiths Carrie L. , Gibson Jacob L. , Luu Jacqueline A.
Published: November 2023

Exercise training has proven to be beneficial in the prevention of disease. In addition, exercise can improve the pathogenesis and symptoms associated with a variety of chronic disease states and can attenuate drug‐induced adverse effects. Exercise is a drug‐free polypill. Because the benefits of exercise are clear and profound, Exercise is Medicine®, a joint initiative between the American Medical Association and the American College of Sports Medicine, was launched in 2007 to call on all health care providers to counsel patients and prescribe exercise in the prevention and treatment of chronic disease states. Pharmacists play an increasing role in direct patient care and are the most accessible health care providers in the community. Thus, pharmacists should be knowledgeable in counseling patients on the amount and type of exercise that is appropriate for various conditions and disease states. The aim of the study was to determine the prevalence of didactic course offerings in U.S. pharmacy school curricula regarding training in exercise prescription. School websites were accessed for information regarding course offerings in Pharm.D. programs. The majority of U.S. pharmacy schools do not offer courses with a focus on the role of exercise in disease prevention or exercise prescription in disease management. When offered, such courses are commonly titled with descriptors such as lifestyle/behavioral modifications, wellness, disease prevention, and health promotion which comprised of several modifiable behavior topics affecting health and disease. No institutions offer a course dedicated solely to exercise prescription.

Support or Funding Information

None
Blended learning within an undergraduate exercise physiology laboratory
Authors: Elmer Steven J , Carter Kathryn , Armga Austin J , Carter Jason R
Published: November 2023

In physiological education, blended course formats (i.e., integration of face‐to‐face and online instruction) can facilitate increased student learning, performance, and satisfaction in classrooms settings. There is limited evidence on the effectiveness of utilizing blending course formats in laboratory settings. We evaluated the impact of blended‐learning on student performance and perceptions in an undergraduate exercise physiology laboratory. Using a randomized, crossover design, four laboratory topics were delivered in either a blended or traditional format. For blended laboratories, content was off‐loaded to self‐paced video demonstrations (~15min). Laboratory Section 1 (n=16) completed blended laboratories for 1) neuromuscular power and 2) blood lactate while Section 2 (n=17) completed blended laboratories for 1) VO2max and 2) muscle electromyography. Both sections completed the same assignments (scored in a blinded manner using standardized rubric) and practicum exams (evaluated by two independent investigators). Pre‐ and post‐course surveys were used to assess student perceptions. Most students (~79%) watched videos for both blended laboratories. Assignment scores did not differ between blended and traditional laboratories (P=0.62) or between sections (P=0.91). Practicum scores did not differ between sections (both P>0.05). At the end of the course, students’ perceived value of the blended format increased (P<0.01) and a greater percentage of students agreed that learning key foundational content through video demonstrations prior to class greatly enhanced their learning of course material when compared to a pre‐assigned reading (94% vs. 78%; P<0.01). Blended exercise physiology laboratories provided an alternative method for delivering content that was favorably perceived by students, and did not compromise student performance.
Student Perceptions and Effectiveness of Team‐Based Learning in an Undergraduate Anatomy and Physiology Course
Authors: Luckey Stephen , McLaughlin Nathan
Published: November 2023

Team‐based learning (TBL) is a student‐centered pedagogical technique that engages students in their education. Students are required to learn concepts on their own before coming to class and their acquisition of this knowledge is assessed through a short multiple‐choice assessment. Students first take the assessment individually and then with their team. The remaining class time is spent applying the concepts and solving application problems with their team, culminating in a class‐wide discussion on their choice of answers. This pedagogy is purported to improve student participation, independent learning, problem solving, and promote development of skills required for teamwork. We implemented TBL in an undergraduate anatomy and physiology (A&P) course and evaluated students’ perceptions of TBL and its effectiveness. Upon completion of the second of two A&P classes, students complete a TBL‐specific survey, called Team‐Based Learning Student Assessment Instrument. In general, we found that students perceived that TBL increased their level of accountability, students had a preference for TBL, and students indicated that they were satisfied with TBL. The aggregate data indicates that students had an overall favorable experience with TBL. A 22 multiple‐choice question test was administered three weeks after the A&P classes were completed to compare students who learned A&P in a TBL‐based class with those who were taught primarily by traditional lectures. Although, students who learned A&P through TBL had a higher score, the difference was not statistically different between the two student cohorts. In conclusion, undergraduate students were very positive to the use of TBL as a teaching strategy for A&P. Moreover, it appears that the use of TBL to deliver A&P was at least as effective as traditional lecture‐based classes.
Students as the Unit and Instrument of Analysis for the Assessment of Advising
Authors: Johnson Kathryn M.S. , Greene Kathleen , Guttchen Emma , McLeod Ruth , Paquin Zachary W. , Young Megan K.M.
Published: November 2023

Since the 1970's, advising has been one of four areas of faculty evaluation (with teaching, scholarship/professional activity, and service/campus citizenship) at Beloit College, a small residential liberal arts college in the Midwest. Advising can occur in many different ways, but can be considered a form of teaching, and faculty members’ approaches to teaching and advising are closely related. Assessment of faculty advising for the tenure process at the institution is limited, but includes a consensus within the department about the faculty member's ability to engage in conversations with students. Evaluation is primarily determined by the accessibility of the advisor to the students, with less acknowledgment of the content of the conversation or student gains. To understand what students are learning from advising interactions and the effectiveness of advising, four student facilitators were trained and actively participated in the development and implementation of student‐facilitated student and alumni focus groups (8 total groups, 6 student, 2 alumni). Participants (n=51, 40 current students, 11 alumni) assembled in small groups (4–12 participants/group) and student facilitators (2–4 facilitators/group) asked participants a series of questions pertaining to their experiences with advising. Student facilitators recorded and analyzed focus group responses. Comparing responses between current students and alumni provided evidence of similar experiences, with alumni responses providing the advantage of retrospection. Student facilitators identified six themes: 1) students are much more likely to have influential conversations and seek advice from family, friends, and peers, rather than from academic advisors; 2) a good advisor is honest and knows how to “be real”; 3) advisees should be open‐minded and come prepared; 4) pre‐major advising varies from horrible to wonderful; 5) peer mentoring works and students love it; and 6) according to alumni, advising happens everywhere. Based on their analysis, the student facilitators concluded that students recognize that positive, effective, and successful advising involves a two‐way relationship between the advisor and the advisee. Working closely with the student facilitators to analyze and interpret the focus group responses has helped us identify institutional advising strengths and avenues for evaluating and addressing weaknesses.

Support or Funding Information

This research was supported by the Beloit College Office of the Provost and Dean of the College.
Contrasting Force Reduction at the Greater Trochanter Using Different Surgical Procedures for Relief of Greater Trochanteric Pain Syndrome
Authors: Taylor Victor , Wood Addison , Belmares Ricardo , Guttmann Geoffrey , Reeves Rustin
Published: November 2023

INTRODUCTION

Greater Trochanteric Pain Syndrome (GTPS) is associated with hip pain from repeated trauma to the greater trochanter bursa. Surgical procedures cut the iliotibial tract (ITT) in order to relieve the pressure around the greater trochanter. We propose that the ITT may not be the primary cause of GTPS. In this study, we hypothesize the primary cause of GTPS is the force generated by the gluteus maximus (gmax) tendon where it inserts onto the gluteal tuberosity of the femur.

METHODS

Force measurements were made using a K‐scan portable tactile pressure measurement system (Tekscan, Inc., S. Boston, MA). Tests were performed on 6 unembalmed cadavers. Cadavers were stabilized on a gurney at the hip. The skin on the top half of the thigh was reflected and superficial fascia removed to expose the ITT. A 7cm incision was made between the ITT and tensor fascia latae muscle. Next, a force sensor pad was placed in the incision between the greater trochanter and ITT. Three categories were used for motion measurements: normal (no cut), ITT cut, and gmax cut. For each category, a range of motions was measured at 0º, 10º, and 15º adduction while subjected to 0º, 10º, 20º flexion and/or extension. Each measurement was made in triplicates.

RESULTS

A total of 12 hips were observed in the study. Two‐way Analysis of Variance statistical analysis was used to compare force generated from the normal (uncut) hips to hips with either the gmax tendon or ITT cut. Preliminary results indicate more reduction in force in the hips with the ITT cut; however, some relief of force over the greater trochanter was seen with the gmax tendon cut.

CONCLUSION

Taking into account the surgical approaches, the gmax tendon cut is the more invasive procedure, and these data suggest the ITT cut to be more effective at relieving force on the greater trochanter, with much less trauma to the patient. More studies will be conducted in the future.
Manganese (Mn) in Human Teeth
Authors: Jelaca‐Tavakoli Maria , Gerlach Raquel F. , Djuric Marija
Published: November 2023

A preliminary non‐invasive chemical analysis of dental enamel was conducted on healthy permanent teeth from various Serbian archaeological settings. This provisional report suggests significance of until now by anthropologists rather overlooked concentrations of Manganese (Mn) accumulated in human teeth. Remarkably high concentrations of Mn isolated from a sample from Vinca warrant this report and urges further interdisciplinary efforts. This pilot study is a part of a larger ongoing study that aims to investigate links between changes in human health and factors affecting diverse environmental and geographical contexts. The toxic levels of Mn in human hard tissues adds to pre‐existing anthropological tool kit as it recognizes and rationalizes both pre‐historic and contemporary connections between environmental pressures, human health and behavior. High concentrations of Mn isolated from deciduous and or permanent teeth have been directly linked to distressed development, neurodegenerative, neuropsychiatric disorders and reproductive health. Therefore, measuring concentration of Mn could potentially improve our understanding of associations between human health and behavior in anatomical, anthropological, forensic, and clinical contexts.
PRELIMINARY ANALYSIS OF SKELETAL TRAUMA FROM AN ATYPICAL EARLY COLONIAL PERIOD PIT BURIAL WITH COMPARISON TO FRACTURES OBSERVED AMONG TYPICAL LATE INTERMEDIATE PERIOD (ca AD 1250) ABOVE‐GROUND TOMBS IN THE ANCASH REGION OF HIGHLAND PERU
Authors: Titelbaum Anne , Ibarra Bebel
Published: November 2023

An atypical subterranean pit burial discovered under a house floor at a prehistoric highland site in Ancash, Peru contains the skeletonized remains of adults and children who appear to have been deposited in a single event. It was hypothesized that the mass grave represents a deposit of individuals who were killed in a situation associated with warfare. To test this hypothesis, a macroscopic analysis of the traumatic injuries of a minimum number of 44 adult skeletons from the pit burial was compared to the pattern of injuries sustained by individuals from an earlier time period who were interred in more typical above‐ground tombs. Results demonstrate that the skeletons from the pit burial demonstrate 20 healed and unhealed traumatic injuries, many of which are found on the posterior aspects of the crania. In contrast, the individuals from the earlier time period demonstrate a low prevalence (1.6%) of postcranial fractures related to falling injuries, and relatively high frequency (33%) of healed and unhealed cranial injuries that cluster on the front left side of the face. Whereas this latter pattern of injury is reflective of face‐to‐face combat, the pattern of injury sustained by the individuals from the pit burial may suggest that the individuals were fleeing their assailants. Implications of these findings are explored.

Support or Funding Information

Visiting Scholarship awarded by the American Association of Anatomists
Comparative anatomy of the ischiorectal fossa and pudendal canal in humans and domestic animals
Authors: Rodriguez‐Sosa Jose R. , Hall Margaret , Adrian Brent , Plochocki Jeffrey H
Published: November 2023

Increasing development of veterinary medicine and use of non‐rodent research models have led to the frequent use of the comparative approach to focus on the anatomy of human and other species. However, as the anatomy of any species has not been studied as much as human, comparisons often fail to produce meaningful conclusions. This is particularly the case when the species compared to human are domestic mammals, which already offer significant structural differences due to their wide variation as species. For example, the ischiorectal fossa (ischioanal fossa in humans) and the pudendal canal, both important elements of the pelvic and perineal regions, are barely described in domestic mammals. This is especially true for the pudendal canal and the neurovascular elements contained in it. As part of our efforts to study the anatomy of pelvis and perineum in several species we have focused on the ischiorectal fossa and pudendal canal using human and domestic animals. Using silicone casts and dissections of the ischiorectal fossa, pelvic wall, and perineum of dogs (n=16), goats (n=9), pigs (n=9), horse (n=3), cats (n=3), and humans (n=22), we have initially defined the particular shapes of the fossa, the pudendal canal and the structural elements that contribute to make their walls in these species (e.g. pelvic diaphragm, sacrotuberal ligament, etc.). Moreover, we have also defined the specific neurovascular elements contained in them (caudal rectal and pudendal nerves, internal pudendal vessels, etc.). Among some interesting findings we found that, unlike in humans, the pudendal canal in domestic animals is not within the ischiorectal fossa. In these species, there is a ‘conceptual’ fossa and a ‘real’ one. The pudendal nerve and vessels (and other associated elements) are compressed against the pelvic wall by the pelvic diaphragm to form the pudendal canal. Then, unlike in humans, the pelvic diaphragm separates caudally from the pelvic wall to generate a ‘real’ ischiorectal fossa.

Support or Funding Information

Midwestern University Intramural Funds
Trabecular Bone mass and Daily Travel Distance in Mammals
Authors: Chirchir Habiba , Ruff Christopher B. , Helgen Kristofer M. , Potts Richard
Published: November 2023

The novel energetics of bipedalism affords humans the ability to walk and run for long distances; for instance, humans in traditional societies are known to walk up to 11km a day. Compared to their close relatives, humans appear unique in their ability to travel long distances, and it has been posited that this ability conferred human ancestors an advantage in exploiting large home ranges, tracking down prey, avoiding predation and scavenging for meat and marrow, and was related to changes in body shape in some members of early Homo. To better understand the anatomical adaptations that offered advantages to members of our genus, it is useful to employ comparative models of living mammals that bear adaptations for long distance travel and running. Cursorial mammals, in comparison to non‐cursorial ones, display external structural adaptations that minimize mass, such as having thin, distally‐tapering limbs to reduce the energetic costs of moving the distal limb; however, it is unclear how internal anatomical structures vary. Specifically, it is not clear how trabecular bone mass varies in related taxa with differing daily travel distances. It is plausible that taxa with long daily travel distances have adapted to greater energetic demands with decreased trabecular bone mass in limbs relative to those with short daily travel distances, as a means of minimizing energetic costs associated with moving and maintaining greater mass.

To test this hypothesis, we measured trabecular bone mass (TBM) in fore‐ and hindlimb articulations of canids (Crocuta crocuta, Canis mesomelas, Lycaon pictus, Vulpes vulpes, Canis lupus), felids (Panthera onca, Panthera pardus, Acinonyx jubatus, Puma concolor), and cercopithecines (Chlorocebus aethiops, Erythrocebus patas, Theropithecus gelada, Papio anubis)—taxa underlined represent those with long daily travel distances (>10km/day). We accounted for body size differences by dividing TBM by body mass. TBM was measured using peripheral Quantitative Computed Tomography scans taken through epiphyseal regions. The sample sizes per species ranged from N=5 to N=20.

Our overall results show that, instead of minimizing mass as a way of reducing energetic expenditure, mammals with longer daily travel distances display higher TBM, which is consistent with observations of greater bone mass resulting from greater physical activity in experimental and exercise science studies. These results are not only consistent with the conventional understanding of bone functional adaptation, but also support the idea that recently documented variation in trabecular bone structure among hominins was not specifically related to a suite of adaptations for long‐distance travel and running in early Homo, but were more influenced by changes in physical activity levels.

Support or Funding Information

This study was supported by the Peter Buck Postdoctoral Fellowship at the National Museum of Natural History, Smithsonian Institution.
Variability in the post‐hatching growth trajectory of alligators from eggs incubated with and without the eggshell
Authors: Gonzalez Estefania , Doyle Janelle , Noriega Marlene , Hocson Anna , Membreno Nelson A. , Elsey Ruth M. , Owerkowicz Tomasz
Published: November 2023

Archosaur embryos use their eggshell as a source of calcium for normal development and growth. Our previous work on eggs of the American alligator (Alligator mississippiensis) showed that physical removal of the eggshell during egg incubation results in viable but diminutive hatchlings with inferior skeletal material properties. When maintained on a twice weekly ad libitum diet of dry formula chow (minimum crude protein 50% w/w), experimental hatchlings (n=26) from eggshell‐less eggs grew at rates similar to their control siblings (n=23), and at three months post‐hatching were still significantly smaller in total mass (−10%) and length (−3%). When the study was repeated with an identical ad libitum diet offered thrice a week, all animals grew at a significantly higher rate than previously (1.3 g/day versus 0.2 g/day). Further, experimental animals (n=35) showed accelerated growth and caught up in size to control animals (n=49). Depending on the clutch (n=4), significant differences between treatments in whole body size disappeared by the first, fourth, fifth, or eighth week. Time to convergence of growth trajectories was dependent on animal size at hatching, with smaller experimental animals taking longer than larger experimental animals to catch up to sibling controls. These results suggest that compensatory growth of crocodilians can be accomplished with an adequate increase in food intake and without supplementation of dietary calcium. We conclude that alligator growth trajectories are a function of embryonic calcium provisioning (via the eggshell), feeding frequency, and clutch‐specific genetic effects.
Ontogenetic cranial and postcranial regional variation in bone strength: comparisons in two archaeological populations
Authors: Garofalo Evan M , Holmes Megan A
Published: November 2023

Divergent developmental patterns in cranial and postcranial skeletal elements have been demonstrated in both traditional osteometric dimensions and measures of bone strength properties. These differences have been attributed to the separate driving forces of varying functional demands in each distinct regions. Additionally, it has been shown that postcranial long bone strength properties are genetically constrained relative to body size during growth. Yet, few analyses have considered whether regional patterns are similar across populations. Here we test these relationships in the Tigara and Arikara, two genetically separate archaeological populations which demonstrate differing subsistence practices. We expect that patterns of development in cranial and postcranial elements will correspond with both distinct functional demands and conserved genetic determination of body form throughout ontogeny.

Strength properties and linear measurements were taken for mandibles, femora, and humeri from Arikara (Sully site; n=41) and Tigara (Point Hope, n=44) individuals. Ages ranged from infancy to younger adulthood and were determined by dental eruption, and examination of skeletal maturity. Both bending strength (Zx) and bending rigidity (Ix) were calculated for each element along the sagittal plane utilizing bi‐planar radiography, external latex molds for limb elements, and hollow beam modeling. To assess developmental relationships between crania and postcrania, variables were subjected to loess regression and percent adult attainment analyses.

Results reveal divergent growth trajectories between skeletal regions within and between populations. As expected, ontogenetic attainment of strength properties followed functional demands within cranial and postcranial regions. Mandibular strength attained near‐adult strength earlier in adolescence in accordance with the onset of an adult diet. Postcranial strength continued to develop into later adolescence, related to increases in body mass particularly in femora. Interestingly, loess regressions showed that postcranial robusticity was significantly different between populations throughout growth, whereas population differences in mandibular robusticity only emerged later in adolescence. Our initial results suggest mandibular strength is developmentally plastic while postcranial robusticity is largely conserved. These differing trends are likely due to ongoing functional demands on the mandible and the relationship of postcranial elements to body size.

Support or Funding Information

Wenner‐Gren Foundation, Gr. 8114
Polyisomerism, Anisomerism, and the Evolution and Development of the Vertebrate Head Muscles
Authors: Ziermann Janine M , Diogo Rui
Published: November 2023

Early vertebrates like cyclostomes (lampreys and hagfish) have many muscles that appear as linear series of similar and equivalent structures, also called polyisomeres. In the first half of the 20th century William K. Gregory postulated that there is an evolutionary trend to reduce the numbers of repeating structures and/or to modify them into more specialized structures, which he designated as anisomerism. Similarly, “Williston's Law” is a trend towards a reduction in number and/or specialization in function of the bones of the skull. Interestingly, most of the discussion about anisomerism, polyisomerism, and Williston's Law focus on hard tissues. Here we provide an encompassing overview of the cephalic muscle evolution in vertebrates and show that there is (1) a trend to have less polyisomeric (serially similar) and more specialized muscles (anisomerism), and (2) a parallel between ontogeny and phylogeny, i.e. the same trends observed in evolution are observed in development. That is, it is important to stress that the decrease in polyisomeric muscles and increase in specialized muscles does not reflect the total number of cephalic muscles in the adult specimen. For example, during the cephalic muscle evolution from the last common ancestor of gnathostomes to humans 27 polyisomeric muscles were lost, but a single muscle (interhyoideus) got specialized into numerous muscles that are present in the adult human (ca. 22 muscles of facial expression).
Scaling of the Ectotympanic Tube and Tympanic Membrane Diameter among Catarrhine Primates
Authors: Fricano Ellen E. I. , DeLeon Valerie Burke
Published: November 2023

The ectotympanic portion of the ear is often used as a phylogenetic marker among primates. However, the factors influencing growth and adult structure of this region are not well studied. The ectotympanic tube is a C‐ or U‐ shaped tube that is fused to the petrosal part of the temporal bone. In catarrhine primates, the ectotympanic tube consists of a bony part between the tympanic membrane and the external auditory meatus and an external cartilaginous part. In ceboids and strepsirrhines the ectotympanic tube is almost completely cartilaginous. It has been suggested that the bony ectotympanic tube may be an adaptation to reduce noise produced during mastication. The present study suggests that the length of the ectotympanic tube is dictated by relative brain size and spatial packing, specifically the lateral expansion of the brain relative to the cranial base. This study examines the relationship between the length of the ectotympanic tube and other related structures, including brain volume, basicranial lengths and widths, and tympanic diameter. The sample includes CT data of adult primates from a wide range of catarrhine species. Two males and two females of each species were included where available. The results of this study show that ectotympanic tube length is positively allometric relative to endocranial volume, but negatively allometric when regressed on body mass. Tympanic diameter has a weaker correlation with brain size and body size, and is negatively allometric when regressed on either. Length of the ectotympanic tube was shown to be significantly correlated with basicranial breadth and endocranial volume, suggesting that these two factors may cause the ectotympanic tube to lengthen in some primates.
Dental Wear, Molar Shape and Dietary Adaptation in Early Australopithecus
Authors: Bauer Nathan M , Middleton Emily R , Ward Carol V
Published: November 2023

The evolution of the ability to process hard‐to‐chew food is considered to be a key innovation in the origin of the Australopithecus‐human clade. This conclusion is based on consideration of the best‐known species of early Australopithecus, A. afarensis. However, the discovery of an even earlier species A. anamensis has led to the realization that these species are likely two ends of an evolving lineage and that A. anamensis may not have been as specialized for chewing difficult foods. If so, this would lead to a significant reconsideration of the biology of the first Australopithecus and the origin of the genus.

Here, we test two hypothesized differences between A. anamensis and A. afarensis that have led to these interpretations. First, we test the hypothesis that A. afarensis had relatively lighter wear on its anterior teeth compared with the earlier A. anamensis. Total occlusal area and area of exposed patches of dentine were measured from photographs of fossil specimens using the ImageJ software package. We calculated the amount of dentine exposure relative to occlusal area on each tooth and standardized the amount of dentine exposure on the first molar. Second, we tested the hypothesis that A. afarensis had higher tooth crowns with straighter sides, and possibly relatively larger occlusal areas. To quantify tooth crown height and contours, casts of molar teeth were scanned with a NextEngine scanner, and 3D polygonal models were created for each molar tooth. Pairs of teeth were scaled to the same cervical area and a best‐fit algorithm used to align the models. Comparison of minimum distances between the surfaces was calculated and a heat map of surface difference created. Magnitude of deviations between the crown surfaces was calculated along the crown, which allows comparison of differentially worn teeth.

Sample sizes are small, but compared to the rate of wear on the first molar, A. anamensis anterior teeth were more heavily worn anteriorly than those of A. afarensis. Molar crowns were also taller with more sloping sides, seen in significant increase in average deviation from A. anamensis crowns away from the base of the tooth. These results support the observations that A. afarensis shifted its dietary behavior from greater processing with the anterior dentition and increased emphasis on mastication with taller molar crowns with relatively larger occlusal surfaces that could withstand more wear. Thus, the dietary adaptation of A. afarensis likely did not fully characterize the origin of the lineage.
Cervical Vertebral Morphology and Neck Mobility in Gibbons (Hylobates lar) and Humans
Authors: Grider‐Potter Neysa , Goto Ryosuke , Nakano Yoshihiko
Published: November 2023

The form and function of the primate cervical spine is poorly understood. Specifically, how the bony morphology of the cervical vertebrae facilitates spinal range of motion within primates is not known. Within mammals, primate cervical vertebrae present relatively unique morphologies, such as the uncinate processes. The objective of this study was to investigate the relationship between vertebral morphology and range of motion in the cervical spine of gibbons and humans. Vertebral morphology is variable within the cervical column (i.e. the morphology of C3 is different from that of C7). Range of motion also varies between intervertebral joints. These variations allow us to explore the relationship between form and function intraspecifically. We predict that range in flexion will be greater in vertebrae with taller bodies, extension inhibited by long spinous processes, and the range of lateral flexion will be lesser in vertebrae with longer transverse process length and taller uncinate processes. These hypotheses were tested using humans and gibbons (Hylobates lar).

Morphological variables were quantified by digitizing cervical vertebral specimens (n=130) using a Microscribe 3DS and measured using Rhinoceros 3DM. Gibbon range of motion was measured from radiographs of maximum flexion, extension, and lateral flexion movements (n=1) and human range of motion was collected from the literature. Ordinary least squares (OLS) regression was used to test the intraspecific relationships between vertebral morphology and ranges of motion. In both gibbons and humans, regression results indicate a relationship between the range of lateral flexion and the length of the adjacent transverse process (p<0.1) but no relationship between the other variables. It may be that soft tissue influences ranges of flexion and extension more so than bony morphology. It is also possible the intraspecific differences are too minute to show a significant pattern. An interspecific comparison could elucidate a pattern.

Support or Funding Information

This project was supported by the National Science Foundation's East Asia and Pacific Summer Program.
The Application of Iodine‐Enhanced Micro‐CT Scanning Protocols to Analyze Multiple Tissue Types and Organ Systems in Mouse Embryos with Short‐term Gestational Hypoxia
Authors: Fisher Rebecca E. , Chapman Gavin , Dunwoodie Sally L. , Kusumi Kenro
Published: November 2023

We have previously demonstrated that mutations in Hes7 and Mesp2 genes, coupled with short‐term gestational hypoxia, significantly increase the range and severity of vertebral defects in a mouse model (Sparrow et al., 2012). In addition, disruptions of the Notch pathway result not only in vertebral, but also muscle defects (Fisher et al., 2012). These studies utilized skeletal preparations to document the range of vertebral defects, while micro‐dissections were conducted to investigate muscle defects. These techniques are relatively labor‐intensive and not amenable to analyses of multiple tissue types and organ systems within each specimen. In order to facilitate the analysis of multiple tissues in whole embryos, we investigated the utility of iodine‐enhanced microCT scanning protocols. A series of experiments were conducted to determine the optimal percentage concentration and duration of staining for 17.5‐day‐old mouse embryos. Embryos were fixed in 4% paraformaldehyde and subsequently stained with various concentrations of Lugol's iodine solution (25%, 50%, 75%, 100%), for different lengths of time (2, 5, 10 days). Images were acquired using a SKYSCAN 1172 micro‐CT scanner, with an X‐ray source at 70kVp and 142 μA, or 55kVp and 181 μA, using a 0.5 mm aluminum filter. The iodine staining protocols did result in visualization of a diversity of soft‐tissue structures including skeletal muscle, blood vessels, and internal organs. However, the specific parameters of the staining protocols greatly impacted the quality of the images, with low concentrations (25%) resulting in poor resolution of soft tissue and high concentrations (100%) resulting in tissue deformation. Results also indicate that the duration of staining as well as the delivery of the stain (one dose versus a step‐wise progression) may affect outcomes. Despite these challenges, this study suggests that iodine‐enhanced micro‐CT scanning protocols can be utilized to conduct whole embryo analyses of defects related to hypoxic conditions during development.

Support or Funding Information

Funding for this project was provided by the American Association of Anatomists and the University of Arizona.
Use of Axial CT Scans to Assess Early Postnatal Development of the Internal Nares: a Test of Reliability
Authors: Gupta Anmol , Meaike Joshua , Pagano Anthony , Curcio Daniella Franco , Som Peter , Laitman Jeffrey T.
Published: November 2023

Human newborns are exclusively nasal breathers due to an anatomical configuration of the aerodigestive tract, similar to those of non‐human primates. Thus, choanal stenosis and other upper airway obstructions may be serious conditions among infants. Morphometric studies lack standardized methods to investigate size, proportion and position of the internal nares in relation to the skull. This study tests the hypothesis that 3D coordinates for landmarks and craniometric points taken on axial CT scans can be reliably used to assess choanal aperture and craniofacial anatomy via 3D geometric morphometrics. We used the computer program Osirix® to identify 16 landmarks on 23 axial scans of monkey skulls (Macaca mulatta) as a model to test accuracy. Two observers underwent four training sessions to plot the landmarks on specimens apart from the study sample. Each observer performed three assessments per specimen and no specimen was evaluated twice in the same day. We assessed landmark accuracy using Generalized Procrustes Analysis by optimal superimposition, scaling by Centroid Size and measured the procrustes distances to interpret data. The obtained interobserver errors were higher than 5%, which indicates that 3D landmark coordinates obtained from axial slices generate considerable interobserver variation and low reproducibility of measurements between structures or bone regions situated in different planes. There was no significant difference in interobserver accuracy in identifying standard craniometric points or regional landmarks assessed by ANOVA. This study indicates that collection of 3D coordinates from axial slices to assess the complex morphology of the choanae and how it changes with growth and development involves intrinsic errors of measurement that must be addressed and controlled when performing geometric morphometric analysis. Next step of this project is using volume rendered 3D CT scans and obtain coordinates for the same landmarks to determine interobserver variability, assess accuracy, and validate reproducibility.

Support or Funding Information

Icahn School of Medicine's Summer Student Investigator Program Award/CNPq ‐ Brazilian National Counsel of Technological Development
Pole‐Shark (Galeorhinus galeus): Seriated CT‐scanned Cross‐sections Every 1mm of the Rostral Extremity and Reconstructions
Authors: LE FLOCH‐PRIGENT PATRICE P , VERDEILLE Stéphane
Published: November 2023

The 23 first cm of a pole‐shark (Galeorhinus galeus, Linnnaeus 1758) which total length was estimated to 1m, was CT‐scanned every 1 mm. The shark had been frozen and the prelevment included the pectoral fins. The CT‐scan apparatus was a Siemens somatom definition with 64 detectors. The native, frontal cross‐sections were reconstructed every 1 mm all along the longitudinal axis. 28 external or deep reconstruction’ aspects were defined. The morphological and topographical results were interesting and numerous. The eyes were voluminous inside large orbital cavities. The encephalon laid in a narrow and stretched intra‐cranial cavity with three vesicles. The cervical vertebrae were “diabolo” shaped surrounding the medulla. The digestive apparatus was placed just below the anterior face of the vertebral column. The seriated CT‐scan with reconstruction is actually an unvaluable method for the morphological studies. This method is completetely justified as numerous species are endangered.
Musculoskeletal Anatomy Education: Evaluating the Influence of Different Methods of Delivery on Medical Students Perception and Academic Performance
Authors: Peeler Jason , Longo Alison , Bergen Hugo
Published: November 2023

Introduction

Medical schools have traditionally used a dissection‐based approach for educating students about musculoskeletal (MSK) anatomy. There is a growing trend towards the use of prosected, and 2 or 3‐D imaging materials as learning resources. While data may suggest that these methods of delivery enhance the learning environment, controversy still exists among medical educators about the most efficient or effective way to educate students.

Purpose

The main objective of this investigation was to examine whether the method of educational delivery would influence student perceptions about learning, and academic performance on MSK anatomy exams.

Methods

Undergraduate students from the same medical school were compared. One cohort was educated using a dissection based teaching model; the second cohort was taught using a prosection based method of delivery. All other aspects of the MSK curriculum were the same, including contact hours. Information was gathered about student perceptions using a standardized survey that compared 6 different methods of delivery (dissection/prosection/lecture/case‐based/on‐line/medical imaging) on 8 specific learning objectives. Survey results were compared against student performance on MSK practical exams.

Results

Ninety‐three students (dissection=39, prosection=54) participated. Only 27 students had previously taken an anatomy course. Both groups rated learning via medical imaging and case based scenarios highly. Each cohort ranked their specific method of delivery (dissect vs prosect) in the top 3. There was no significant difference in the academic performance between the groups.

Conclusions

Data support the inclusion of medical imaging and case‐based scenarios as a key component of MSK anatomy curriculum, but suggest that little difference exists in student performance when comparing dissection and prosection based curriculums. These results should help guide the selection of effective MSK anatomy delivery methods within medical programs.

Support or Funding Information

Funding provided through the University of Manitoba teaching and Learning Enhancement Fund
Prosection based gross anatomy lab for dental students
Authors: Sanders Luke E , Dorius Geoff , Morton David A , Hutcheson David A
Published: November 2023

While developing a new dental specific gross anatomy lab curriculum at the U. of Utah, we were faced with the task of determining how best to use the cadaver lab for teaching first year dental students. Relative to the existing anatomy course for medical students, two problems emerged. First, the critical tissues for dental students, the head and neck, are among the most complex and difficult to dissect. For novice dissectors it is very difficult to do a quality dissection and preserve the structures of interest. Second, with only two hours each week, the time allotted for lab was not sufficient to create head and neck dissections, even for very skilled dissectors. To address these two issues, a prosection based lab curriculum was instituted. By using prosections that were prepared in advance by experienced dissectors, and forgoing traditional student dissection, we aimed to present detailed anatomy clearly and in an efficient manner. As the students arrived to lab they were divided into small groups and paired with an instructor to learn a specific set of objectives. Over the course of the lab, students would rotate through the stations, each of which had a prosection prepared to teach a specific set of anatomical structures. Where appropriate, non‐cadaver based activities were used to supplement and help integrate concepts and overriding principles. Students were also given access to the lab outside of scheduled lab teaching time so that they could come in and study using the prosections on their own. Critically, these high quality prosections have made it possible to teach students very detailed anatomy in a relatively short period of time. The prosections have also allowed the students to see structures and relationships that are often destroyed in a traditional lab setting where students do the dissections. Initial results have been encouraging. Student feedback has been positive, and scores on practical exams suggest students are learning the material. Our future plans include creation of a greater number of prosections to allow material to be taught both systemically and regionally, as well as a 4th year elective dissection course for senior dental students who wish to gain the skills that would come from the more traditional dissection experience.