Browsing by Author "Maddux, Scott D."
Now showing 1 - 20 of 34
- Results Per Page
- Sort Options
Item An Analysis of Student Satisfaction with Active Learning Techniques in an Online Graduate Anatomy Course: Consideration of Demographics and Previous Course Enrollment(2023) Bradley, Libby; Meyer, Kim; Robertson, Taylor; Kerr, Marcel; Maddux, Scott D.; Heck, Amber; Reeves, Rustin; Handler, EmmaPurpose: Online learning has become an essential part of mainstream higher education, allowing greater access for students. With the increase in online course enrollment, specifically that of anatomy, understanding online teaching best practices is critical. Active learning has previously shown many benefits in face-to-face anatomy courses, including increases in student satisfaction. Currently, no research has measured the satisfaction of several active learning techniques implemented in an asynchronous, online graduate anatomy course. Methods: This study compared the student satisfaction achieved by four active learning techniques with consideration of demographics and previous course enrollment. Survey questions consisted of multiple-choice and Likert-style that asked students to indicate their level of satisfaction with the active learning techniques. One hundred seventy (170) students completed the online anatomy course and surveys. Results: Students were more satisfied with question constructing and jigsaw than with concept mapping and team-learning module. Additionally, historically excluded student groups (underrepresented racial minorities) were more satisfied with active learning than White students. Age, gender, previous anatomy experience and/or online course experience did not influence the satisfaction of the active learning techniques. However, students with higher GPAs and those who had no graduate degree were more satisfied with the active learning techniques than students who had lower GPAs and those with a graduate degree. Conclusion: These findings provide evidence that students enrolled in an online graduate anatomy course were satisfied with the active learning techniques, dependent on the specific technique, demographics, and previous course enrollment. Results provide anatomy educators with a better understanding of which techniques work best in an online anatomy course. Currently, there is a lack of research comparing active learning techniques in an online learning environment. These findings provide online anatomy educators with evidence that active learning techniques improve satisfaction, with consideration of student demographics and previous course enrollment.Item Anatomical Adaptation to Climate: Patterns of Covariation Between Brain and Nasal Morphology(2019-03-05) Maddux, Scott D.; Pineda, JonathanAnatomical adaptation to climate: Patterns of covariation between brain and nasal morphology Jonathan Pineda* & Scott D. Maddux, Ph.D.** *TCOM, **Center for Anatomical Sciences, Dept. of Physiology and Anatomy, UNTHSC PURPOSE: Previous research has shown that the geographic distributions of both brain and nasal shape are highly correlated with climatic variables. Specifically, individuals indigenous to cold-dry environments typically exhibit relatively wider brains (for retention of heat), and taller/longer/narrower nasal passages (for enhanced warming and humidification of respired air) compared to individuals from hot-humid climates. While these ecogeographic patterns of brain and nasal shape are both well established, the spatial interaction of these two structures in relation to climate has not been as rigorously investigated. METHODS: We employed CT scan data collected from a total of 30 human crania from the Arctic Circle (9 female, 6 male) and West Africa (8 female, 7 male). 3D digital models were subsequently rendered for each cranium using the 3D Slicer software program and a total of 35 craniofacial landmarks were then placed on each 3D model, permitting assessment of both linear measurements (i.e., Euclidean distances) and 3D spatial relationships via univariate and multivariate statistical analyses. RESULTS: Largely consistent with previous research, permutational t-test results indicate that individuals from the Arctic Circle possess shorter (p=0.029) and wider (p=0.002) braincases compared to West Africans. Similarly, Arctic natives were also found to possess both taller (p=0.0001) and narrower (p=0.001) nasal passages. While on average the Arctic sample also possessed a longer nasal passage (69.8 mm) compared to the Africans (67.1 mm), this difference was not statistically significant (p=0.097). Moreover, a simultaneous-fit two-block partial least squares (2B-PLS) analysis of 3D coordinate landmarks, reveals a significant pattern of covariation (RV=0.37, p=0.012) between nasal and brain morphology, with the first PLS dimension (46.3% of the total covariation) reflecting a significant association between relative brain width and nasal height, width, and length (r=0.74, p=0.032). CONCLUSIONS: Cumulatively, these results are consistent with previous studies, and support the hypothesis that climate has simultaneously influenced both brain and nasal anatomy. Moreover, our 2B-PLS results suggest that the relative spatial positioning of the nose may actually contribute to overall brain thermoregulation by differentially influencing airflow under the basicranium in different climatic regimes.Item Assessing Ecogeographic Variation in the Nasal Passages Utilizing 3D Semilandmarks(2021) Higgs, Lyndee; Maddux, Scott D.; Thai, ElizabethPurpose: Prior research has shown strong statistical relationships between geographically-patterned variation in nasal skeletal morphology and global climatic conditions. Specifically, the nasal skeletons of individuals indigenous to cold-dry environments tend to be longer, taller, and especially narrower, than those from hot-humid environments. As the nose heats and humidifies inspired air, this morphological patterning is believed to reflect the specific air-conditioning demands of different climates. However, while it is widely assumed the morphology of the nasal skeleton accurately reflects that of the functional (soft-tissue) nasal passages, the existence of ecogeographic variation in the three-dimensional (3D) nasal soft tissues has yet to be empirically demonstrated. Thus, this study investigates 3D shape variation in decongested soft-tissue nasal passages of individuals of European (EA) and African (AA) descent (n=15). Methods: Using 3D Slicer and Avizo, a total of 260 semi-landmarks were collected from the decongested nasal passages of each individual. General Procrustes Analysis (GPA) was then used to align the semilandmark configurations and a Principal Component Analysis (PCA) was subsequently performed using the Geomorph package in R. Results: PC1 (20.2%) largely contrasts EA individuals with positive PC1 scores (relatively narrower nasal passages) from AA individuals with negative PC1 scores (relatively wider nasal passages). Conclusions: These results generally conform to morphological expectations, suggesting a concordance between skeletal and decongested soft-tissue nasal anatomy. This study thus provides the impetus for future research investigating the relationship between variation in nasal soft-tissue anatomy and air-conditioning physiology.Item Assessing Ecogeographical Variation in the Nasal Passages Utilizing 3D Semilandmarks(2021-05) Ward, Lyndee A.; Maddux, Scott D.; Menegaz, Rachel A.; Handler, EmmaPrior research has shown strong statistical relationships between geographically-patterned variation in nasal skeletal morphology and global climatic conditions. Specifically, the nasal skeletons of individuals indigenous to cold-dry environments tend to be longer, taller, and especially narrower, than those from hot-humid environments. As the nasal passages heat and humidify inspired air for entry into the lungs, this morphological patterning is believed to reflect the specific air-conditioning demands of different climates. However, while it is widely assumed the morphology of the nasal skeleton accurately reflects that of the functional (soft-tissue) nasal passages, the existence of ecogeographic variation in the three-dimensional (3D) nasal soft tissues has yet to be empirically demonstrated. This study investigates 3D shape variation in decongested soft-tissue nasal passages of individuals ancestrally derived from cold-dry (CD) and hot-humid (HH) environments (n=20). Using 3D Slicer and Avizo, a total of 260 semilandmarks were collected from the decongested nasal passages of Each individual. General Procrustes Analysis (GPA) was then used to align the semilandmark configurations of all 20 individuals and a Principal Component Analysis (PCA) was subsequently performed using the Geomorph package in R. Our results indicate PC1 (19.13%) largely contrasts CD individuals with positive PC1 scores (relatively narrower nasal passages) from HH individuals with negative PC1 scores (relatively wider nasal passages). These results generally conform to morphological expectations, suggesting a general concordance between skeletal and decongested soft-tissue nasal anatomy. This study thus provides the impetus for future research investigating the relationship between ecogeographic variation in nasal soft-tissue anatomy and air-conditioning physiology.Item Craniofacial Bone Mineral Density in Mice with Osteogenesis Imperfecta(2019-05) McBride, Alexandra H.; Menegaz, Rachel A.; Muchlinski, Magdalena N.; Maddux, Scott D.Osteogenesis imperfecta (OI) is a rare genetic disorder characterized by the abnormal synthesis and assembly of type I collagen, a major organic component of bone. Clinical manifestations of the severe OI type III include small body size, limb deformities, and low bone mineral density (BMD) within the post-cranial skeleton. OI type III often co-occurs with craniofacial defects, such as dentinogenesis imperfecta (DI). The goals of this study are: (1) to examine whether type I collagen defects, as seen in OI type III, affect BMD within the craniofacial skeleton; (2) to determine whether BMD varies among specific region of the craniofacial skeleton; (3) to examine whether diet-related variation in biomechanical loading is related to higher craniofacial BMD. The homozygous recessive murine mouse (OIM-/-) is a model for OI Type III. Similar to human OI patients, OIM-/- mice exhibit low post-cranial BMD, smaller body size, and DI. OIM-/- mice and WT littermates were weaned at 21 days and raised on either hard (high loading) or soft (low loading) diets. This resulted in four genotype x diet treatment groups: OIM-soft (n=3), OIM-hard (n=6), WT-soft (n=3), and WT-hard (n=9). Micro-CT scans were collected at 16 weeks (skeletal maturity). BMD was measured using Bruker CTAnalyzer software for eight regions of interest (ROIs) within the mandible (TMJ, corpus at the second molar, and symphysis), facial skeleton (nasal bone, maxilla at the second molar, premaxilla at the incisor), and cranial vault (frontal and parietal bones). Pairwise Mann-Whitney U tests were used to statistically compare BMD between genotypes (α = 0.100). When controlling for diet, WT mice had significantly greater BMD values than OIM mice at each ROI except at the maxilla at M2. Although variation between treatment groups, a general trend for increased BMD in "high" strain regions, such as the mandibular symphysis or the maxillary incisor, existed. Lastly, WT mice raised on a hard diet were observed to have the highest BMD measurements across each region the craniofacial skeleton, however no significant differences were observed between OIM-/- mice raised on hard versus soft diets. These results suggest that craniofacial BMD is generally lower in individuals with type I collagen defects, consistent with the post-cranial presentation. Additionally, regions associated with high strain during routine masticatory loading exhibited increased BMD as compared to regions of the skull that experience relatively "low" strain during chewing. While diet-associated loading may influence craniofacial BMD, in this study type I collagen status appears to be the primary determinant of BMD.Item Craniofacial Morphology of Juvenile Mice with Osteogenesis Imperfecta(2020-05) Steele, Ashley T.; Menegaz, Rachel A.; Maddux, Scott D.; Kesterke, Matthew J.Osteogenesis Imperfecta (OI) is a heritable connective tissue disorder affecting the synthesis and structure of type I collagen (Col1) due to autosomal dominant mutations in proa1(I) or proa2(I) collagen genes (COL1A1 and COL1A2). Clinical manifestations of the severe OI type III include bone fragility, reduced physical stature, and midface hypoplasia resulting in a "triangle face" phenotype. Current treatment options have low-success rates and focus primarily on alleviating symptoms through surgical interventions and pharmacologic use of antiresorptive drugs. The homozygous OI murine (OIM-/-) mouse model has a nonlethal, recessively inherited mutation of the COL1A2 gene and exhibits adult cranial and post-cranial phenotypes similar to humans with severe OI type III; however, the juvenile phenotype is unknown. The goals of this study are: (1) to determine if significant differences in craniofacial skeletal shape and size are present at the age of weaning (21 days/4 weeks) in the OIM-/- mice compared to the wild type (WT) and (2) to determine if these differences are still significant when adjusted for the allometric effects of body size. OIM-/- and WT littermates were weaned at 21 days and scanned in-vivo with a Skyscan 1176 micro-CT system. Craniofacial geometric landmarks were collected using 3D Slicer software and were subsequently used to calculate interlandmark distances (ILDs) and centroid sizes. ILDs were scaled against skull/mandible centroid size to account for the effect of overall body size on shape analyses. Mann-Whitney U-tests were used to compare both absolute and relative (scaled) ILDs between the genotypes. Craniomandibular centroid sizes and absolute linear distances (skull, rostrum, palate, and mandible lengths) demonstrate that the OIM-/- mice are smaller overall than their WT littermates. When scaled to centroid size, juvenile OIM-/- mice have a decrease in nasal length, mandibular diastema length, and basicranium but an increase in cranial vaults, midface heights, and both maxillary and mandibular toothrow lengths compared to WT mice. For a given skull length, OIM-/- mice have shorter faces in both the anteroposterior and dorsoventral dimensions. The morphometric changes seen in the juvenile OIM-/- mice replicate the "triangle face" and relative macrocephaly that is commonly seen in human pediatric populations with OI. This suggests that this mouse model can potentially be used to investigate the structural changes underlying the human OI phenotype and for potential therapeutic interventions, such as biomechanical loading, myostatin knock-out, and pharmaceutical therapies. Additionally, the results of this study can be used to inform future investigations of Col1 in craniofacial development. Continuing to evaluate the etiology of this disorder can lead to better treatment options to improve the quality of life for patients with OI, especially pediatric patients.Item CT-based assessment of lower limb surface area, volume, and tissue composition: Implications for ecogeographic rules of thermoregulation(2022-05) Carey, Barclay L.; Maddux, Scott D.; Romero, Steven A.; Gonzales, LaurenAnthropological research into human climatic adaptation has shown that global variation in skin surface-area to body volume ratio is generally consistent with theoretical predictions of ecogeographic rules. NSF has funded a research project in which human subjects will undergo full-body computed tomography scanning, and physiological testing during exposure to climatic extremes, to permit direct evaluation of associations between morphological variation and thermoregulatory physiology. This project entailed the development of analytical methods for the NSF project, which will be used to 1) compare CT-derived SA/V ratios to traditional estimation methods, and 2) to evaluate potential volume differences in internal tissue compositions (e.g., bone, muscle, fat).Item CT-based assessment of lower limb surface area, volume, and tissue composition: Implications for ecogeographic rules of thermoregulation(2022) Carey, Clay; Maddux, Scott D.Purpose: Anthropological research into human climatic adaptation has shown that global variation in skin surface-area to body volume (SA/V) ratio is generally consistent with theoretical predictions of ecogeographic rules. However, most studies have ignored the fact that internal body volume is comprised of various tissues (e.g., bone, muscle, fat) which exhibit different thermoregulatory properties. To address this issue, NSF has recently funded a research project in which human subjects will undergo full-body computed tomography (CT) scanning, and physiological testing during exposure to climatic extremes in an environmental chamber, to permit direct evaluation of associations between morphological variation and thermoregulatory physiology. Accordingly, the goal of the current project is to develop analytical methods for the NSF project, which will be used to 1) compare CT-derived SA/V ratios to traditional estimation methods, and 2) to evaluate potential volume differences in internal tissue compositions (e.g., bone, muscle, fat). Methods: 20 full body CT scans were selected from the New Mexico Decedent Image Database, a repository of CT scans made available to researchers by the New Mexico Office of the Medical Examiner. CT scan processing was performed in the Avizo software program. Appropriate anatomical landmarks were identified for segmentation of the hip, knee, and foot. The boundary between torso and lower limb is defined by a transverse plane between left and right greater trochanters. Separation of thigh and leg is defined by a similar plane between the medial and lateral midpoints of the knee on the tibial plateau. A final plane at the ankle passes through the medial and lateral malleoli. Identification of tissue types (bone, muscle, adipose) from the CT data began with generally accepted Hounsfield unit (i.e., density) ranges. These threshold ranges include +400 HU and higher for bone, -29 to +150 HU for muscle, and -190 to -30 HU for adipose. Results: Landmarks employed to orient planes of anatomical division were found to be readily identifiable across all specimens, permitting accurate collection of surface area and volume data for each of the 4 regions of interest (lower limb, thigh, leg, foot). In contrast, the use of basic Hounsfield unit threshold ranges was not found to permit reliable differentiation between bones, muscle, and adipose tissues. In particular, thresholding rages for bone had to be substantially altered to account for density-related differences between cortical bone, trabecular bones, and bone marrow. Hounsfield unit ranges for muscle and adipose did not need as much adjustment, but selections required more manual segmentation for contouring and removal of scanning artifacts. Conclusion: The methods developed by this project allow differences in tissue composition to be accurately accounted for during assessments of body volume. Thus, these methods provide advantages over traditional volumetric methods which assume tissue uniformity, and consequently, are well positioned to facilitate future experimental research into the relationships between anatomical variation and thermoregulatory physiology.Item Dental size reduction in the domesticated fox: Implications for the 'domestication syndrome'(2020) Maddux, Scott D.; Franciscus, Robert; Kharlamova, Anastasiya; Southard, Thomas; Trut, Lyudmila; Wood, EmmaPurpose: The "Domestication Syndrome" is an explanatory model for the suite of morphological and physiological traits common across domesticated species. One oft-cited morphological change common to domesticates is a reduction in dental size relative to wild progenitors, yet there are a dearth of studies exploring this dynamic. Moreover, domestication theory has long emphasized that dental size reduction is a byproduct of artificial selection for non-aggressive behavior. The Russian fox domestication experiment provides an untapped source for studying this evolutionary dynamic because it provides a controlled, long term study of selection for non-aggressive behavior and attendant morphological consequences. Yet, the dentition of these experimental foxes has not been heretofore studied. Methods: We employed univariate and multivariate comparisons of maxillary P4, M1, and canine mesiodistal length, buccolingual breadth, and crown height of the canine, as well as mandibular M1 mesiodistal length and buccolingual breadth. These data were collected in sex-balanced samples of the unselected (n=50), tame (n=49), and aggressive (n=50) experimental strains. All measurements were taken directly on macerated, fully cleaned elements using Vernier calipers affording measurement accuracy to 0.05 mm. Results: Consistent with expectations from the 'domestication syndrome' model, tame fox skulls exhibited statistically significantly reduced tooth dimensions in virtually all comparisons relative to both unselected and aggressive strain individuals. Tame-selected foxes also demonstrated more variability in the dentition. Conclusion: These results appear to support domestication hypotheses and highlight the utility of dental evidence as a morphological indicator of reduced aggression.Item Diagnostic Value of Dynamic Ultrasound in Supination-External Rotation Injuries(2018-08) Fisher, Cara L.; Reeves, Rustin E.; Berg, Rance E.; Maddux, Scott D.; Rosales, Armando; Wood, Addison R.Ankle syndesmosis injuries are common and range in severity from subclinical to grossly unstable. Definitive diagnosis of these injuries can be made with plain film radiographs if the injury is severe enough, but often is missed when severity or image quality is low. Computed tomography (CT) and magnetic resonance imaging (MRI) can provide early definitive diagnosis regardless of severity, but are costly and introduce the patient to radiation when CT is used. Ultrasound diagnosis may circumvent many of these disadvantages by being inexpensive, efficient, and able to detect subtle injuries without radiation exposure. This study evaluates the ability of ultrasound to detect subtle supination-external rotation (SER) ankle syndesmosis injuries with a dynamic external rotational stress test. Nine all male fresh frozen specimens were secured to an ankle rig and stress tested to 10 Nm of external rotational torque with ultrasound monitoring at the tibiofibular clear space. The ankles were subjected to syndesmosis ligament sectioning and repeat stress measurements of the tibiofibular clear space at peak torque. Stress tests and measurements were repeated three times and averaged. Data was analyzed using a two-way repeated measures ANOVA.Item Evaluating Ecogeographic Variation in Human Nasal Passages Using In-Silico Decongestion of the Nasal Cycle(2020-05) Thai, Elizabeth; Maddux, Scott D.; Menegaz, Rachel A.; Rosales, ArmandoTo protect the lungs from desiccation and thermal damage, inspired air must be heated to core body temperature (37°C) and 100% saturated with water vapor upon reaching pulmonary tissues. The majority of air conditioning occurs in the nasal passages, where heat and moisture are transferred to inspired air from nasal mucosa via concurrent convection and evaporation. Given that physiological demand for air conditioning is largely dependent on the external environment, many studies have noted strong associations between climate and ecogeographic patterning of human nasal morphology. Specifically, these studies have shown that individuals indigenous to cold-dry environments exhibit relatively longer, taller, and narrower nasal passages than individuals from hot-humid climates. These apparent climate-mediated morphologies are assumed to reflect functional differences, with longer, taller, and narrower nasal passages in cold-dry climates enhancing respiratory heat and moisture exchange via the increased relative mucosal surface area. However, due to the nasal cycle, direct associations between nasal passage dimensions and mucosal surface area to airway volume (SA/V) have been challenging to quantitatively establish. The nasal cycle refers to the alternating congestion and decongestion of the venous sinuses lining the nasal turbinates and part of the septum. In this study, we tested associations between nasal passage height, breadth, and length dimensions and passage SA/V ratio via 3D morphometric assessments of computed tomography (CT) cranial scans in 8 individuals - four of European ancestry (EA) and four of African ancestry (AA). 3D models of the nasal passages were created using 3D Slicer software. Airway models were artificially dilated in-silico to simulate fully decongested nasal passages. Morphometric measurements of passage height, breadth, and length dimensions; mucosal surface area; and airway volume were collected from both congested and decongested airway models. Consistent with expectations, there appears to be no noticeable difference in median congested SA/V ratios (p=0.8) between EA subjects (SA/V=0.99) and AA subjects (SA/V=0.99). There was a trend for EA subjects to have greater median decongested SA/V ratios (SA/V=0.51) than AA subjects (SA/V=0.49), however, this difference did not reach statistical significance with the number of subjects included in our study (p=0.2). Further analysis reveals EA individuals' nasal length to be significantly longer than AA individuals (p=0.028) while all other measurements (nasal height and nasal breadth) demonstrate expected trends but are not significant (all p≥0.8). Our results provide evidence to support that the congestion level of subjects on CT imaging could significantly impact morphometric analysis of the nasal cavity and computational fluid dynamics (CFD) analysis of nasal airflow - and thus is important to consider when creating models for CFD analysis. Future research employing CFD analyses may provide insight into how morphological differences impact intranasal heat and moisture exchange thus providing further insight into how ecogeographic variation in human nasal morphology may reflect climatically adaptive differences in nasal function.Item Evaluating Energetic Demands on the Human Nose Within a Regional Sample(2019-03-05) Kelly, Alexa; Maddux, Scott D.; Prazak, PatrickPurpose: It is widely recognized that the primary function of the nose is to warm, humidify, and filter air in preparation for entry into the lungs. Accordingly, geographic variability in nasal anatomy has long been attributed to climatic adaptation. However, as the human nose is also the primary respiratory conduit during normal breathing, it must facilitate a sufficient intake of oxygen to meet metabolic demands. Thus, given that body size also exhibits considerable geographic-mediated variation, it has long been argued that metabolism may represent a confounding influence on human nasal morphology. In particular, given its critical role in air-conditioning, it has been hypothesized nasal passage breadth should most strongly correlate with climate. Conversely, it has been suggested that nasal height and length dimensions may represent compensatory mechanisms for ensuring that a sufficient volume of oxygen can be inspired to meet body size/metabolic demands. Methods: To test these hypotheses, we obtained CT scan data for 35 modern human crania from the Bronze-Age archaeological site of Tepe Hissar, Iran. CT dicom images for each cranium were initially processed using the 3D Slicer software program, rendering a 3D digital model which was subsequently oriented in the Frankfurt Horizontal position to permit anthropometry. A total of 61 craniofacial landmarks were then placed on each 3D model, from which 15 linear measurements of nasal morphology were ultimately calculated using the Euclidean distance formula. These 15 nasal measurements were then employed in conjunction with body size/stature estimations (i.e., metabolic proxies) derived from associated post-cranial measurements, to assess the relationship between body size and nasal anatomy. Results:Following theoretical expectations, our results indicate that, within this one geographic sample (i.e., holding climate constant), no measure of nasal passage breadth was significantly correlated with body size (all p-values [greater than] 0.06). Conversely, all height and length measurements of the nasal aperture and internal cavity were found to be significantly correlated with body size (all r-values=0.48-0.62, all p-values Conclusions: Collectively, these results support the assertion that airway height and length dimensions reflect metabolic demands for sufficient intake of oxygen, while nasal breadth dimensions are more likely driven by climatic factors.Item Investigating Associations Between Asthma and Nasal Abnormalities: A Computed Tomography (CT) Approach(2023) McCullough, Jason "Drew"; Maddux, Scott D.; Cho, Elizabeth; Ward, LyndeePurpose: Asthma affects over 300 million people worldwide and 3,500 people suffer asthma related deaths each year. Although there is no clear cause of asthma, approximately 90% of asthmatics suffer from cold/exercise induced bronchoconstriction, a symptom triggered by the inhalation of cold and/or dry air. As the nasal passages account for most of the heat and moisture transferred to inspired air during respiration, anatomical variation in nasal morphology may contribute to asthma development. While the existence of nasal anatomical variants is well documented, little is known about the prevalence of such variants among asthmatics. Methods: Accordingly, this study sought to investigate potential associations between asthma and three common nasal anatomical variants: septal deviations, concha bullosa, and paradoxical turbinate. This study analyzed Computer Topography (CT) scans of a diverse, mixed sex sample (n=242) from the New Mexico Decedent Image Database (NMDID). The asthmatic individuals (n= 120) were identified through associated medical records and compared to a control sample of non-asthmatics (n = 122). CT scans were analyzed using Avizo permitting qualitative coding of each anatomical variant for presence and type. Chi-square tests of independence were then used to test for differences in variant prevalence between the asthmatic and control samples. Results: The results of our study show significantly higher prevalence of concha bullosa in asthmatics compared to control individuals (χ2= 5.87, p=0.015), with 70.0% asthmatics exhibiting at least one pneumatized turbinate compared to only 54.9% of control individuals. Conclusions: This result suggests a potential relationship between the presence of conchae bullosa and asthma, possibly due to this variant negatively influencing intranasal air-conditioning capabilities. Future work employing computational fluid dynamics (CFD) analyses may be able to further elucidate the influence concha bullosa have on nasal passage air flow and conditioning. Such work could provide important insights into the role nasal anatomy may play in asthma prevalence and severity. This project was supported by Texas Center for Health Disparities grants RF00241 & RI40241Item INVESTIGATING ECOGEOGRAPHIC VARIATION IN SUPERIOR AND FUNCTIONAL ETHMOIDAL BREADTH IN INTERNAL AIRWAY DIMENSIONS(2021) Grace, Caroline; Maddux, Scott D.; Schaefer, CeceliaSuperior Ethmoidal Breadth (SEB = maximum breadth between the left and right frontoethmoidal sutures) is widely employed as a proxy for internal nasal airway dimensions. SEB is also commonly argued to evince climatic adaption in modern humans, as populations living in cold-dry environments predictably exhibit narrower SEB dimensions than those inhabiting tropical environments. However, as SEB anatomically spans the upper nasal airways (common and superior meatuses) and the ethmoid air cells, the accuracy of SEB as a proxy for airway dimensions remains questionable. Here, we evaluate the correlation between SEB and internal airway dimensions using linear measurements collected on CT scans from a mixed-sex sample of human crania (n=217) ancestrally derived from sub-Saharan Africa, Europe, East Asia, and the Arctic Circle. Our results demonstrate SEB is highly correlated (r=0.807, p< 0.0001) with functional airway breadth (FEB), suggesting SEB is a reliable proxy. ANOVA results indicate, in addition to significant differences in SEB (F=36.5, p< 0.0001), regional differences exist for common (F=3.95, p=0.009) and superior (F=3.19, p=0.024) meatus breadths and ethmoid air cell breadth (F=9.01, p< 0.0001). Specifically, the African-derived sample consistently exhibit the widest nasal dimensions and the Arctic-derived sample the narrowest dimensions. Our results indicate a positive scaling relationship between SEB and internal airway breadths, with the wider SEB values of the African-derived sample actually underestimating their disproportionately wider common and superior meatuses. Cumulatively, these results empirically support use of SEB as proxy for upper nasal airway breadth.Item Major Musculoskeletal Injuries and the Menstrual Cycle: A Case Study(2023) Prado, Cynthia; Maddux, Scott D.Background: There is a clear difference between males and females in the incidence of certain sports injuries. For example, females are about 9 times more likely to experience anterior cruciate ligament (ACL) tears, while males are about 7 times more likely to experience calcaneal (Achilles) tears. These discrepancies warrant further evaluation into the core differences between males and females, one of which is the menstrual cycle. During the first 15 days of the of the menstrual cycle, estrogen levels rise. There is discussion in medical literature about estrogen’s effects on the musculoskeletal system, which may begin to correlate these injury rates and menstruation. One study measured estrogen levels and presynaptic inhibition in males and females during day 1 and day 15 of the menstrual cycle, and found that both measurements were significantly different on day 15. This suggests that as estrogen concentration increases in the first half of the menstrual cycle, gamma-aminobutyric acid (GABA) in the spinal cord is attenuated, decreasing pre-synaptic inhibition, resulting in altered skeletal motor control. Another study evaluated estrogen’s effect on failure load, which is the force necessary to break or tear a certain object. It analyzed two groups of ovariectomized rabbits, administering estrogen supplementation to one and not the other. It found a reduction in failure load in the hormonal substitution group, implying that tendons and ligaments under estrogen’s influence could rupture at a lower applied force. Another study analyzed the extracellular matrix (ECM) enzyme lysyl oxidase (LOX), which oxidizes lysin in collagen and elastin, mediating the cross-linking between these ECM fibrils. It showed that estrogen inhibits LOX activity in engineered ligaments, implying that the increased estrogen in vivo may decrease the stiffness of tendons/ligaments in women, leading to increased risk of injury. This case illustrates two major musculoskeletal injuries in a young female patient that both occurred within the first fifteen days of her menstrual cycle. Case information: 17-year-old female sustained a right ACL tear during a track meet on day 5 of her menstrual cycle. The same female at age 27 sustained a left Achilles tear during a recreational volleyball game on day 6 of her menstrual cycle. In both occurrences, the patient had no previous injury to the area, no medical conditions, and was not taking any medication. Conclusions: The fact that both of this patient’s major musculoskeletal tears occurred during the first week of her menstrual cycle suggests that changing hormones may have influenced these injuries. The studies that support this conclusion have evaluated estrogen’s effects on the musculoskeletal system and concluded that estrogen has been shown to 1) decrease presynaptic inhibition, 2) reduce failure load, and 3) decrease the stiffness of tendons/ligaments. This research together may begin to explain the correlation between this patient’s injuries and her menstrual cycle. More research is needed on this topic, so that we can definitively identify all risk factors for these kinds of injuries and begin to take steps toward prevention for the appropriate athletes.Item Modern Day Osteometrics: Testing the Concordance of Postcranial Measurements Collected Manually vs. Digital Methods(2020) Maddux, Scott D.; Kelly, Alexa; Tadlock, JohnathanThe use of medical imaging (CT/MRI) modalities for the collection of osteometric data has become increasingly common in anatomical research. However, the relative accuracy of skeletal measurements collected using these modalities is poorly established. Thus, the purpose of this study was to test the hypothesis that osteometric data collected manually and digitally are reliably comparable. The software program 3D Slicer was chosen for collection of digital measurements because of its widespread usage in modern morphometric research. Maximum femoral length, maximum humeral length, humeral epicondylar breadth, and anteroposterior femoral head diameter (FHD) were collected on 36 humeri and 23 femora. Each of these measurements was taken three times using different methods: (1) physical anthropometry, (2) digitally directly from raw Computed Tomography (CT) scans, and (3) digitally from full-bone 3D models generated from CT scans. Maximum length and epicondylar breadth measurements were all found to be highly comparable between all three measurement methods (Lin's Concordance coefficients 0.96-0.99). Conversely, FHD measurements collected via the two digital methods were found to be poorly comparable to manual measurements (Lin's CC: 0.0832-0.160) with average differences of approximately 7.0 mm (16%). These results suggest that measurements collected digitally are generally comparable to those collected manually using traditional osteometric tools. Methodological discrepancies in measuring FHD may relate to the difficulty of reliably orienting the proximal femur in 3D digital space. Future research into these discrepancies is necessary as FHD is frequently used in regression formulae for estimating stature, body mass, and metabolic requirements.Item Nasal morphology and health disparities in asthma: A study assessing semi-automated tools for processing computed tomography scans in 3D morphometric research(2020) Maddux, Scott D.; Kim, Suhhyun; Das, SiddharthPurpose: As the nasal complex is predominantly responsible for respiratory heat and moisture exchange, it has been suggested that abnormal nasal anatomy may increase asthmatic symptoms. Recent research has increasingly turned to medical imaging modalities, requiring processing of large samples (n>10,000). The lack of automated procedures for scan processing has represented a significant obstacle for such studies. Accordingly, the purpose of this project was to evaluate the applicability of a newly developed subroutine for the NIH-funded 3D Slicer program to semi-automate the alignment of cranial CT-scans into the Frankfort Horizontal plane for subsequent morphometric assessment as a part of a larger asthma-related study. Methods: Selected CT scans were drawn from 5,221 asthma and control cohorts from JPS hospital in Fort Worth, TX. Each scan was first processed using traditional methods for aligning the cranium into the Frankfort Horizontal plane, followed by a trial employing a new python-based alignment subroutine for "SlicerMorph" extension on 3D Slicer for comparison. Results: Overall, the subroutine showed a significant improvement in image processing times, reducing alignment time for a single scan by approximately 60%. The accuracy of alignment was found to be substantially improved due to the relative ease of locating three fiducial landmarks (left orbitale, left porion, right porion) for alignment compared to the traditional method. Conclusion: This novel subroutine allows for efficient processing of CT scans. Furthermore, we expect use of this subroutine will significantly decrease intra- and inter-observer error, increasing the accuracy of obtained morphometric data.Item Nasal morphology and health disparities in asthma: A study assessing semi-automated tools for processing computed tomography scans in 3D morphometric research(2021) Das, Siddharth; Kim, Suhhyun; Maddux, Scott D.Purpose: As the nasal complex is predominantly responsible for respiratory heat and moisture exchange, it has been suggested that abnormal nasal anatomy may predisposes certain individuals to asthma. Recent research into anatomical etiologies of asthma have increasingly turned to medical imaging modalities(e.g., CT/MRI scans) to quantify 3D nasal anatomy across large samples(n > 10,000) of asthmatic patients. However, lack of automated and semi-automated procedures for scan processing has represented a significant obstacle for such anatomical studies. Accordingly, the purpose of this project was to evaluate the applicability of a newly developed subroutine for the NIH-funded 3D Slicer software program designed to semi-automate the alignment of cranial CT-scans into the Frankfort Horizontal plane for subsequent morphometric assessment. Methods: Our study sample consisted of 10 high-resolution cranial CT scans of dried skulls. These CT scans were first processed using traditional methods for aligning the cranium into the Frankfort Horizontal plane, followed by a second trial employing a new python-based script alignment subroutine for the "SlicerMorph" extension module of 3D Slicer. Results: Overall, the automated subroutine showed a significant improvement in image processing times, reducing alignment time for a single scan by approximately 60% from 50-60 minutes down to 15-20 minutes. Furthermore, the accuracy of alignment was found to be substantially improved. Conclusion: This novel subroutine will allow future researchers to efficiently process segmented scans of human crania while decreasing observer error yet increasing the morphometric accuracy.Item Next Generation Sequencing Assessment of Mitochondrial Oxidative DNA Damage in Cognitive Impairment: Shedding Light on Health Disparities in Mexican Americans(2022-08) Reid, Danielle M.; Phillips, Nicole R.; Barber, Robert C.; Sumien, Nathalie; Thorpe, Roland; Planz, John V.; Maddux, Scott D.Currently, Alzheimer's Disease (AD) is listed as the 5th and 7th leading cause of death in the US aging (individuals 65+ years of age) and general population, respectively. The US aging population has been expanding over time and is projected to triple over the next two to three decades. As this demographic shift occurs, the impact of age-related diseases, including AD will increase. Due to differences in biology, behavior, socio-economic status and health care access, this impact will not be distributed evenly across racial and ethnic divides in the US population. Unfortunately, most scientific data exists for non-Hispanic Whites (NHWs). Although limited in scope, the observations that we have for admixed populations such as Hispanics clearly show that racial/ethnic disparities and etiologies for AD exist; however, the details of these disparities remain to be elucidated. Collaborative research efforts from the Texas Alzheimer's Research and Care Consortium (TARCC) aim to identify ethnicity-specific factors that influence the development and progression of AD among Mexican Americans (MAs) compared to their NHW counterparts, and to better understand the role these factors play. Common risk factors for developing cognitive impairment (CI) in the MA population are stroke, diabetes, obesity, and depression. Although the reasons for the association between cognitive decline and comorbidities remain unclear, the incidence of these comorbid conditions is known to vary greatly across race and ethnicity. Diabetes for example is three times more prevalent among MAs relative to NHWs. Accumulating evidence indicates a correlation between common pathological changes observed in AD and DNA damage, particularly within the mitochondrial genome (mtDNA), which is positioned to be particularly vulnerable to DNA damage. Age-associated decline in mitochondrial function generates an accumulation of reactive oxygen species that are capable of damaging essential biomolecules including DNA and may help explain some of the racial and ethnic differences in etiology that exist for AD. Many forms of oxidative DNA damage exist, but oxidation of guanine (G) to 8-oxo-guanine (8oxoG) is one of the most prevalent lesions and an indicator of mitochondrial dysfunction. Damaged mtDNA, such as 8oxoG serve as important markers of age-related systemic inflammation and upon release into peripheral circulation may exacerbate the physiology and pathophysiology contributing to AD development and/or progression. Current methods for the detection of oxidized bases are limited, costly, cumbersome, and lack reproducibility. Here we describe the use of Illumina-based next-generation sequencing to quantify variants of oxidatively modified G residues in mtDNA of MA vs NHW TARCC participants. Our first study focused on investigating whether impaired mitochondrial function, represented by levels of oxidative DNA damage indicative of 8oxoG differed between MAs and NHWs. Additionally, we evaluated the effects of sex, CI, and type-2 diabetes (T2D) on risk for AD. We discovered variants representing 8oxoG from buffy coat were significantly higher in MAs compared to NHWs. Interestingly, MA females were especially affected, and years of education was significantly associated with 8oxoG load in MAs. We report suggestive evidence that 8oxoG mutational load is associated with cognitive impairment. Further, we identified individual mtDNA haplotypes that render an increased risk for oxidative DNA damage. Our second study used blood-based measurements of 8oxoG from both buffy coat and plasma to determine associations with population, sex, and T2D, for AD risk. We investigate genomic regions specially burdened by 8oxoG affecting mitochondrial function in relation to population and disease. Lastly, we characterize differences in 8oxoG mutational load between buffy coat and plasma portions of blood on assessing AD risk and endophenotype. Our results show that both buffy coat and plasma were significantly associated with population, sex, years of education, and suggest association with AD.Item Sexual Dimorphism in Permanent Human Dentition(2021-05) Aldeeb, Sara; Handler, Emma; Menegaz, Rachel A.; Maddux, Scott D.Sexual dimorphism refers to differences between males and females of the same species. A general pattern of sexual dimorphism is displayed in humans. Across mammalian populations, males generally have a larger body than females. Many studies have shown that, as body mass increases, tooth volume increases isometrically (Ungar, 2014). For example, on average, males have larger teeth than females (Schwartz and Dean, 2005). However, despite clear gross dental size differences, some studies have suggested that males and females also exhibit divergent quantities of enamel (Saunders et al., 2007). Females have been shown to have relatively thicker enamel, and a larger enamel cap area than males (Smith et al., 2006). This reveals an ambiguity. Although males possess overall larger teeth, studies suggest that male dental composition contains less relative enamel than would be expected given their tooth size. Similarly, females have been shown to exhibit smaller teeth than males, but a greater relative amount of enamel. This study has developed a methodological protocol for taking volumetric measures on dental microstructure using computed tomography (CT) scans. This protocol will help future studies evaluate the relative quantity of enamel and dentin in teeth. A better understanding of the volumetric differences in the dental microstructure is imperative to the understanding of dental sexual dimorphism. We examined the dental microstructure using 3D modeling from individuals in the Point Hope population. This population has been known to use their teeth as tools in several ways. We understand the microstructure of the dentition within the sample population may be impacted by some wear and use of dentition within this community. The dental microstructure was examined using 3D modelling in 14 individuals from a sample of the Point Hope population including eight adult females and six adult males of unknown age. Three hundred and twelve total teeth were examined. One hundred and eighty-six teeth came from female subjects, and one hundred twenty-six teeth came from males. The 3D models of the dentition and microstructure of enamel and dentin was generated using the software. Due to a small sample size, analysis of gross dental size and enamel volumes were performed using a one-tailed, non-parametric Mann-Whitney U-Test (a=0.10). Volumetric measurements of the total tooth volume, enamel volume, and dentin volume were recorded for each subject. Our results suggest that there are divergent quantities of enamel between males and females within the mandibular teeth. Specifically, the central incisors, lateral incisors, canines, first premolars, second premolars, and second molars within the mandible showed that there are statistical differences between sexes in dental composition. Males possessed a greater amount of enamel in their mandibular central incisors, lateral incisors, canines, first premolars, second premolars, and second molars. Additionally, the maxillary dentition also demonstrated notable statistical difference in enamel quantity within the second premolars between males and females. Males had a larger enamel quantity within their second molars than females. Males also demonstrated larger average total dental volume (345.59 mm3) than females (342.02 mm3). We have successfully generated a protocol in which future studies could quantify dental microstructure and add to the understanding of dental sexual dimorphism. Further research implementing this protocol for segmenting CT scans and utilizing the segmentation to gather volumetric measurements of dental microstructure should use higher resolution micro-CT scans and a larger sample population.