bluuebunny/crossref_metadata_2025 huggingface dataset:
RNA Next Gen Sequencing of Kidneys from Diabetic Rats Provides Insights Into Reno‐protective Effects Of Vitamin D Receptor Activation
Authors: Prabhakar Sharma S , Kam Katherine , Kottapalli Rao , Yego Chepchumba
Published: November 2023

Introduction

Diabetic nephropathy (DN) is the leading cause of end stage renal disease. The current therapy of DN remains suboptimal despite many currently available options. Recent experimental studies including from our laboratory and clinical reports support the therapeutic potential of vitamin D receptor activators, particularly paricalcitol. However molecular mechanisms underlying such protective effects are unclear. The goal of this study was to evaluate global gene expression changes using next‐generation sequencing‐based transcriptome analysis following paricalcitol treatment in obese ZSF1 rats, a murine model of metabolic syndrome that develops DN.

Methods

All rats were fed with a high fat diet to maintain hyperglycemia from 8 to 31 weeks. The test group of rats was injected subcutaneously twice a week with 0.2 μg of paricalcitol from 21 to 31 weeks. Following treatment, kidneys were harvested and total RNA was isolated and processed for transcriptome analysis using Illumina HiSeq 2500. Paricalcitol‐ treated ZSF1 rats were compared with obese untreated rats. The differential gene list from this analysis was imported into Ingenuity® Pathway Analysis (IPA®) for global transcriptome analysis and pathway mapping.

Results

We detected 650 genes that had a significant change of at least 2 fold based on log 2 fluorescence intensity values. Of these 568 transcripts were up‐regulated whereas 82 transcripts were down regulated. Established pathways that were dominantly regulated include the Wnt signaling pathway that is primarily associated with cell cycle regulation. Specific molecules that were regulated with this pathway are Wnt3 Wnt9B and Wnt11 that were up regulated. Wnt 10b was also down regulated. OX40 signaling that involves regulation of the NF kB pathway was also regulated. Vitamin D signaling molecules that significantly changed following paricalcitol include the transcription factor enhancer binding protein α (EBPα), interleukin‐12 (IL‐12), interferon γ (IFNγ) and IP‐10. Several pathways that have previously been linked to diabetic nephropathy were differentially regulated by paricalcitol. These include endothelial nitric oxide synthase (eNOS) signaling, vascular endothelial growth factor (VEGF), protein kinase C and NF kB.

Conclusions

Paricalcitol treatment induces significant changes of gene expression in the kidney and most of these changes involve up regulation of several genes. Wnt signaling as well as changes in vitamin D signaling are regulated by paricalcitol. Thus the reno‐protective effects by paricalcitol treatment possibly involve inhibition of signaling pathways that have previously been associated with the progression of DN.

Support or Funding Information

Supported by Woirhaye Research Endowment
Whole Genome and RNA Sequencing Identifies Genetic Factors involved in Nephron Deficiency in the HSRA Congenital Solitary Kidney Rat
Authors: Wang Xuexiang , Johnson Ashley C. , Garrett Michael R
Published: November 2023

The HSRA rat is a unique polygenic model of congenital abnormalities of the kidney and urogenital tract, with 50–75% of offspring developing a single kidney. The model also exhibits nephron deficiency (~20% less nephrons) in the remaining kidney, glomerular and kidney hypertrophy, and elevated single nephron GFR, which leads to progressive kidney injury and decline in kidney function with age. A number of animal studies have provided an understanding of the physiological mechanism of injury, but it remains unknown the specific genetic factors that cause failure of one kidney to develop, as well as the mechanism of nephron deficiency in the remaining kidney. A recent genome‐wide association study (GWAS) performed by others using the heterogeneous stock rat (progenitor of the HSRA model), identified genomic loci on chromosomes (RNO) 4, 10, and 14 associated with the solitary kidney trait. The confidence interval for the RNO4 locus is ~4.2 Mb containing 14 genes, the RNO10 interval is ~1.5Mb containing 15 genes, and the RNO14 locus is consistent with locus linked to solitary kidney in the ACI rat. The whole genome was sequenced to a depth of 18X coverage using the Illumina NextSeq500 platform. Sequence alignment and annotation [BN reference genome (UCSC Rn5)], identified 1,776,635 SNP, 314,786 INDEL, and 25,346 structural variants. RNA sequencing of embryonic kidney isolated at key stages of nephrogenesis (E14.5, 15.5, and 16.5) between single kidney and two‐kidney control identified dysregulation of genes linked to cellular movement (p‐value= 2.36E‐06 ‐ 1.49E‐02 n=78/451), cell morphology (p‐value= 1.86E‐05 ‐ 1.49E‐02 n=82/451) and cell‐to‐cell signaling and interaction (p‐value= 8.38E‐05 ‐1.49E‐02 n=68/451). The top canonical pathway was associated with Wnt/b‐catenin (p‐value= 4.89E‐05) which includes Wnt2/Nlk candidates genes and is highly relevant to kidney development. Based on the GWAS, whole genome sequencing, and RNA sequencing, the causative genomic loci were refined to specific genes [c‐Kit (RNO14), Fam58b and Nlk (RNO10), and Met and Wnt2 (RNO4)] that could play a role in the solitary kidney trait and nephron deficiency in the HSRA model. In summary, the identification of the specific gene defect, modifier genes, and signaling pathways that lead to loss of one kidney and nephron deficiency will provide a mechanistic link between the solitary kidney genotype and the development of kidney dysfunction exhibited by the HSRA rat.

Support or Funding Information

Supported by HL094446 (Garrett), UMMC, and Robert Hearin Foundation. Genomics Core [P20 GM103476 [MS‐INBRE‐(Elarsi)], P30GM103328 (CPN‐COBRE) and P20GM104357 (Obesity‐COBRE)
Conditional knockout of astrocytic Kir4.1 channels impairs central respiratory drive despite maintaining a subset of Cx26+ astrocytes within the RTN
Authors: Hawkins Virginia E , Kolling Fred W , Nelson Craig E , Mulkey Daniel K
Published: November 2023

Central chemoreception is the mechanism by which the brain regulates breathing in response to changes in tissue CO2/H+. The retrotrapezoid nucleus (RTN) has been identified as a key locus for central respiratory control. Neurons in this region are intrinsically sensitive to changes in CO2/H+ (i.e. are chemosensitive). RTN astrocytes also function as chemoreceptors by sensing CO2/H+ through inhibition of an inwardly rectifying (Kir4.1‐like) K+ channel, and respond by releasing ATP via connexin 26 (Cx26) hemichannels. This CO2/H+‐dependent purinergic drive from RTN astrocytes has been shown to increase the chemosensitive RTN neuron response by ~30%. However, it is not known whether Kir4.1 in astrocytes is required for RTN chemoreceptor function, and little is known regarding the molecular identity of the chemosensitive astrocyte cell subset. To investigate this we generated an inducible astrocyte specific Kir4.1 channel knockout (Kir4.1 cKO) using GFAP‐CreERT2 and Kir4.1 floxed mouse lines, along with a TdTomato reporter line. Whole‐cell voltage clamp recordings of RTN astrocytes in juvenile brainstem slices from Kir4.1 cKO mice showed the absence of a Kir4.1‐like, CO2/H+ ‐sensitive current. RTN neurons from Kir4.1 cKO brainstem slices show a reduced purinergic component to their CO2/H+ response, suggesting deletion of Kir4.1 from astrocytes may disrupt the ability of these cells to respond normally to changes in CO2/H+. Respiratory activity was measured in adult mice by whole body plethysmography and showed that Kir4.1 cKO mice hypoventilate in 100% O2 and have a reduced tidal volume response to hypercapnia, compared to controls. For examination of gene expression, RTN GFAP‐TdT+ astrocytes from both control and Kir4.1 cKO brainstems were acutely dissociated and single cells were isolated by FACS into 96‐well plates. Single cell qPCR revealed that the majority of astrocytes within the RTN express glial markers Kcnj10 (Kir4.1), Aqp4, Aldh1L1 and Gfap, and NeuN was probed for to exclude neuronal transcript contamination. A subset of RTN astrocytes expressed Gjb2 (Cx26), which unlike Kcnj10 expression, was not greatly reduced in astrocytes from the Kir4.1 cKO mouse RTN. These results demonstrate that Kir4.1 channels in astrocytes contribute to the central drive to breathe, and suggest that RTN astrocytes are a heterogeneous population, with a discrete subset that expresses Cx26. These findings provide insight into the specialized nature of astrocyte chemoreceptors and may identify new targets important for the central control of breathing.

Support or Funding Information

NIH HL104101 (DKM) and F32HL126381 (VEH)
Influence of CO2 and HCO3− on Basal Activity and Acid Sensitivity of Chemosensitive Neurons in the Retrotrapezoid Nucleus
Authors: Goncalves Christopher M. , Kuo Fu‐Shan , Daniel Emily , Mulkey Daniel K.
Published: November 2023

Central chemoreception is the mechanism by which the brain regulates breathing in response to changes in tissue CO2/H+. A region of the brainstem called the retrotrapezoid nucleus (RTN) is an important site of chemoreception. The mechanisms of RTN chemoreception involve direct H+‐mediated activation of chemosensitive neurons, and indirect modulation of chemosensitive neurons by CO2/H+‐dependent ATP‐purinergic signaling. Recent evidence identifies astrocytes as the source of CO2/H+‐evoked ATP release, possibly by a mechanism involving CO2‐mediated opening of connexin 26 hemichannels. However, the extent to which ATP contributes to RTN chemoreception is questionable; some studies report that ATP release from astrocytes is required for chemosensitive RTN neurons to sense changes in CO2/H+, whereas other studies showed that blocking ATP receptors in the RTN decreased (~ 30%) but did not eliminate CO2/H+‐sensitivity of RTN chemoreceptors. Based on evidence that CO2 is required for ATP release by RTN astrocytes, we chose to investigate the contribution of purinergic to RTN chemoreception by comparing the firing responses of chemosensitive RTN neurons to graded acidifications in the presence and absence of CO2 and HCO3−. Cell‐attached recordings were used to identify RTN chemoreceptors in brainstem slices (300 μm thick) isolated from rat pups (P7–11 days postnatal) incubated in a bicarbonate (26 mM) buffered solution by their characteristic response to CO2; i.e., low basal activity in 5% CO2 (pH=7.3; 0.7 ± 0.1 Hz) and high activity in 10% CO2 (pH=7.0; 1.7 ± 0.3 Hz) or 15% CO2 (pH=6.9; 2.2 ± 0.4 Hz). After returning to control conditions (5% CO2; pH=7.3) switching to a bicarbonate‐free HEPES buffered solution (pH=7.3) decreased baseline activity by 0.5 ± 0.4 Hz (T3=5.175, p=0.014; paired t‐test). In HEPES buffer, acidifications to pH=7.0 and pH=6.9 increased activity by 0.65 ± 0.2 Hz and 0.8 ± 0.2 Hz, respectively. In some cases, during prolonged exposure to HEPES baseline activity increased to near control levels, suggesting that removal of CO2/HCO3− from the perfusate only transiently suppressed chemoreceptor activity. These results suggest that RTN chemoreceptors respond more vigorously to hypercapnic acidosis compared to the same acidification in HEPES buffer. This finding is consistent with the possibility that CO2‐evoked ATP release from astrocytes contributes in part to RTN chemoreception. These results also suggest that HCO3− controls baseline activity of RTN chemoreceptors, possibly by influencing intracellular pH or regulating HCO3−‐sensitive K+ channels (i.e., KCNQ).

Support or Funding Information

NIH Grant HL104101
Noradrenergic modulation of chemosensitive neurons in the retrotrapezoid nucleus
Authors: Kuo Fu‐Shan , Barna Bárbara F , Chen Dawei , Takakura Ana C , Mulkey Daniel K
Published: November 2023

Chemosensitive neurons in the retrotrapezoid nucleus (RTN) regulate breathing in response to CO2/H+ changes, and serve as an integration center for other autonomic centers including brainstem noradrenergic neurons. Considering that application of norepinephrine (NE) into the RTN strongly modulates breathing (see abstract by Oliveira et al.) and disruption of NE signaling has been implicated in breathing disorders associated with Rett syndrome, sleep‐disordered breathing and multiple system atrophy, we sought to characterize the effects of NE on chemosensitive RTN neurons. Cell‐attached recordings were used to identify RTN chemoreceptors in brainstem slices (300 μm thick) isolated from rat pups (P7–11 days postnatal) by their characteristic response to CO2; i.e., low basal activity in 5% CO2 (0.2 ± 0.1 Hz) and high activity in 10% (1.8 ± 0.1 Hz) or 15% CO2 (2.1 ± 0.1 Hz ). We found that bath application of NE (1 μM) increased activity by 1.1 ± 0.1 Hz in 48 of 66 cells (73%), decreased activity by 1.0 ± 0.1 Hz in 6 of 66 cells (9%), or had no effect on activity in 12 of 66 (18%) of cells. Interestingly, basal activity but not CO2/H+‐sensitivity differed between each group based on their NE response; e.g., basal activity and firing response to 10% CO2 was 0.4 ± 0.1 and 1.2 ± 0.1 Hz (NE‐activated), 1.1 ± 0.3. and 1.1 ± 0.1 Hz (NE‐inhibited) and 0.03 ± 0.01 and 1.1 ± 0.01 Hz (NE‐insensitive). The excitatory effect of NE on RTN chemoreceptors was dose dependent (EC50 of 235 nM), retained during synaptic blockade (high Mg+2/low Ca2+) and could be mimicked by an α1‐receptor agonist (phenylephrine; 10 μM) and blocked with a α1‐receptor antagonist (prazosin; 1 μM). The inhibitory effect of NE on RTN chemoreceptors was retained during synaptic blockade and blunted by a α2‐receptor antagonist (idazoxan; 1 μM). A subset of NE‐activated cells were inhibited by NE in the presence of prazosin, whereas some NE‐inhibited cells showed an excitatory response to NE in the presence of idazoxan. A third group of RTN chemoreceptors did not respond to NE under control conditions or during hypercapnia, and these cells also did not respond to phenylephrine. In addition, whole‐cell voltage clamp (Vhold= −80 mV; TTX) recordings from CO2/H+‐sensitive RTN astrocytes show the absence of an NE‐sensitive current. These results indicate that i) RTN chemoreceptors are intrinsically sensitive to NE; ii) NE can increase or decrease chemoreceptor activity by α1‐ and α2‐receptor dependent mechanisms, respectively; and iii) NE modulates discrete subsets of RTN chemoreceptors based on basal activity and the differential contributions of α1‐α2‐receptors.

Support or Funding Information

NIH Grant :HL104101
Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) is Crucial for CO2 Signal Transduction in Avian Intrapulmonary Chemoreceptors (IPC)
Authors: Molloy Rhett Gordon , Low Trevor Michael , Bassett Peter Ross , Lonjaret Jean‐Guillaume , Hempleman Steven Curtis
Published: November 2023

CFTR is an anion channel and ABC transmembrane protein which also modulates other anion channels and transporters. Since CFTR is widely expressed in cells that transport anions, and we hypothesize that anion transport in IPC is critical for CO2 transduction, we tested for the presence of CFTR in IPC. Glibenclamide, a non‐selective CFTR inhibitor, and CFTR‐172inh, a highly specific CFTR inhibitor were given separately to pentobarbital‐anesthetized mallards (Anas platyrhynchos, n =15) while recording single cell IPC spike train responses to inspired CO2 steps (0%–7%, 11sec period). Both drugs produced similar results, where IPC discharge with the lowest 2 μmol/kg doses was unchanged from control, while the 4 and 8 μmol/kg doses significantly decreased both mean IPC discharge and phasic adaptation (ANOVA, p<0.01). IPC CO2 sensitivity was completely abolished in 4 CFTR‐172inh experiments and 4 glibenclamide experiments. Results suggest that CFTR is a crucial anion regulating channel involved in IPC CO2 signal transduction.

Support or Funding Information

Support: NIH R15 HL087269‐02.
Pulmonary Arteries Show Differences in the Effects of Angiotensin II Stimulation of Mitochondrial Superoxide on Regulation of Heme Biosynthesis and Soluble Guanylate Cyclase Expression
Authors: Patel Dhara , Kelly Melissa R. , Accarino John J.O. , Sun Dong , Wolin Micahel S.
Published: November 2023

It is well established that Angiotensin II (AngII) increases mitochondrial superoxide levels through the AT1 receptor. Ferrochelatase (FECH), the mitochondrial heme‐generating enzyme, has an iron‐sulfur cluster required for its stability and activity, which could potentially be disrupted by superoxide. We have observed that 24 hr organoid culture of bovine coronary arteries (BCAs) with AngII caused a depletion of mitochondrial superoxide dismutase‐2 (SOD‐2), FECH and soluble guanylate cyclase (sGC), as well as an increase in deficiency in heme (detected by depletion of cytochrome oxidase subunit‐4 (COx4), but not catalase). The heme precursor δ‐aminolevulinic acid (ALA) prevents these effects of AngII through a mechanism that appears to involve promoting protoporphyrin IX (PpIX) accumulation and its stimulation of sGC/cGMP‐activation of protein kinase G (PKG). Thus, in this study we investigated the effects of AngII on 24 hr organoid cultured endothelium‐denuded bovine pulmonary arteries (BPAs). AngII increased mitochondrial (MitoSox/HPLC) and extra‐mitochondrial/cytosolic superoxide (DHE/HPLC) and protoporphyrin IX (PpIX) levels (detected by its surface fluorescence), and it depleted SOD‐2 (western blot) and Cox4 (western blot) protein expression. However AngII did not deplete protein expression of FECH, sGC and catalase (western blot). ALA prevented AngII‐elicited increases in mitochondrial superoxide, and depletion of SOD‐2 and COx4. Furthermore, co‐organoid culture of BPAs with AngII in presence of cGMP‐independent activation of PKG (DHEA (dehydroepiandrosterone)) and cGMP‐mediated activation of PKG (8‐bromo‐cGMP) reverses the increases in mitochondrial and extra‐mitochondrial superoxide induced by AngII in BPA. The increase in PpIX and depletion of heme, but not FECH, suggests that increased mitochondrial superoxide in AngII‐treated BPA is impairing the availability of iron for heme generation from PpIX. Since agents which bind the heme site of sGC appear to protect it from depletion when the sGC heme is oxidized, the observed AngII‐elicited increase in PpIX in BPA may prevent the depletion of sGC. In contrast, AngII did not increase PpIX in BCA, and the depletion of both FECH and heme appears to be a more dominant factor in AngII‐treated BCA. While increased PKG stimulation by PpIX generation from ALA may function to attenuate AngII‐induced increases in mitochondrial superoxide and depletion of heme in both BPA and BCA, and the increase in PpIX observed in BPA treated with AngII may function to prevent the depletion of sGC, and perhaps FECH.

Support or Funding Information

Supported by NIH grant: R01HL115124
Do “Job Aids” Facilitate Retention of Physiology Concepts
Authors: Povlow Michael , Harris David
Published: November 2023

Medical students are tasked with learning and managing large amounts of information and often find it difficult to distinguish between concepts critical for clinical application versus factual information. Since physiology is so conceptual in nature, many students struggle with integrating material due to previously formed study habits where repeated readings were effective. Therefore, it is important for educators to highlight critical information from learning sessions to facilitate student learning. In this study, we hypothesized that providing “job aids” or flash cards with a disease, pertinent questions about the underlying science, a critical graph/schematic for understanding, and a celebrity with the disorder would improve retention of physiology content.

Methods

Students participated in a high fidelity patient simulation or computerized case using lab tutor involving physiology concept. Each student then received a flash card which included a celebrity “mnemonic” relating that person to the session's physiology concept.

Results

A total of 120 second year medical students were recruited to participate in a study about 6 months after the physiology course. A survey with questions asking whether students recognized the celebrity and could match the celebrity with their disease was included. Also, physiology questions were administered as part of a quiz to determine whether concepts supplemented with a job aid were retained better than those not supported by a job aid.

Discussion

Finding ways to improve student retention of physiology material as well as identifying critical concepts versus factoids is paramount to medical educators. The use of job aids which are relatively cheap to develop and design could enable students to better retain some physiology concepts. Aspects such as celebrity information may facilitate better retention as well.
Metric Variation in the Human Sacrum: Costal Process Length among Black and White South Africans
Authors: Wayne Christy Rose
Published: November 2023

Considerable attention has been given to the measureable differences that exist between different human populations in the size and shape of the pelvis, with Africans having a narrower pelvis than Europeans. By collecting data on sacral breadth from a South African skeletal population, this study (1) tests the hypothesis that African blacks possess a narrower pelvis than whites; (2) determines whether the size variation between blacks and white is due to nutritional, historical and social differences, to a genetic basis related to climatic adaptation, or to both; and (3) considers the influence of sexual dimorphism on pelvic size and shape. 393 individuals from the Pretoria Bone Collection (University of Pretoria, South Africa) were studied: 98 white males, 100 white females, 100 black (Bantu) males, and 95 black (Bantu) females. Measurements included anteroposterior and transverse diameters and costal process lengths of the 1st sacral and the 3rd and 5th lumbar vertebrae. White South Africans possess a significantly wider sacrum and significantly longer costal processes than black South Africans. The average maximum diameter of the sacrum was 119 mm for white males, 106.6 mm for black males, 116.7 mm for white females, and 106.4 mm for black females. Two possible interpretations of these results are addressed: (1) Size variation may be a result of nutritional differences related to socioeconomic status; or (2) it may be a result of climatic adaptation based on thermoregulatory principles (Bergmann's rule). A comparison between the sacra of South African and North American blacks and whites did not support the hypothesis that size variation is due only to nutritional differences. Whereas the United States and South Africa share a history of racial segregation, they differ in that this racial segregation is not strictly correlated with nutritional or socioeconomic status in North America, but is so in South Africa. Nevertheless, the sacra of whites are wider in both populations. This comparison did, however, provide some support for the interpretation that size variation in the sacrum is a result of long‐term adaptation to climate. Unlike short‐term variation in stature due to nutritional or socioeconomic status, the wider sacrum of whites and the narrower sacrum of blacks reveals a longer evolutionary history. Hence, this study provides a possible explanation for the origin of metric differences between phenotypic populations according to latitude.
Development of Wing Bone Laminarity in the Pigeon
Authors: Ourfalian Raffi M. , Ezell Kelly , Lee Andrew H.
Published: November 2023

Wing bones of adult birds may have microscopic adaptations for flight. In birds that use continuous flapping flight, circumferential vascular canals are abundant in the humerus and ulna, where they form laminar bone presumably to resist twisting loads during flight. In contrast, the paucity of laminar bone in the radius presumably reflects reduced twisting loads in that part of the wing. Here, we test this biomechanical hypothesis with ontogenetic data. If wing bone laminarity is an avian adaptation to resist flight‐induced torsion, then it should increase with age until maturity. Alternatively, if wing bone laminarity reflects allometry, then laminarity should vary directly with growth rate and decrease with age. We collected 19 pigeons of known age (0 –9 weeks post‐hatching). Transverse sections were cut from the midshaft of the humerus, ulna, and radius. Midshaft bone circumference was measured and used to plot growth curves for each element. From these growth curves, we calculated the mean circumferential growth rate for the elements of each sampled specimen. In elements containing cortical bone, the proportion of circumferential to total canals (laminarity index) was calculated. Linear regression was used to assess the correlation between laminarity and mean circumferential growth rate. Our results reveal that wing bone laminarity is greater in juveniles than in adults. Moveover, as mean circumferential growth rate decreases with age, so does wing bone laminarity. Linear regression analysis suggests that growth rate explains approximately 70% of the variation in wing bone laminarity. We conclude that wing bone laminarity, at least in the pigeon, is not a flight adaptation but instead an expression of ontogenetic allometry. Evolutionary shifts in ontogenetic allometry may explain interspecific variation of wing bone laminarity across birds.
Effects of selection for high voluntary wheel running on sexual dimorphism in the sacrum of Mus musculus
Authors: Asplund Crystal Lynn , Perry Kyler W. , Schutz Heidi
Published: November 2023

Comparative studies have shown that pelvic girdle (os coxae and sacrum) morphology may be influenced by sex and/or locomotion and that a possible evolutionary trade‐off exists between reproductive constraints and locomotor activity. Previous unpublished work explored how sexual dimorphism in the os coxae responds to locomotor activity in Mus musculus through analyses of mice from an artificial selection experiment that bred mice for high voluntary wheel running. Three of the eight lines from this experiment were sampled, representing control (C), selected (HRNORMAL), and selected mini‐muscle (HRMINI) groups, with the mini‐muscle individuals possessing a Mendelian recessive mutation that causes a 50% decrease in skeletal muscle mass. Based on prior comparative work on the pelvis and the specific results from the os coxae of these mice showing differing patterns of dimorphism in shape, density and bone volume, we hypothesized that a similar pattern would be present in the sacrum. Using 122 specimens from the aforementioned experiment, we obtained shape and size (mass and centroid size) metrics of the sacra and compiled these with previously recorded body masses and lengths. ANOVAs of size metrics showed significant differences in body length, mass and sacral centroid size between the lines and sexes. On all metrics, both HR lines were smaller than the C line and the HRMINI line was smaller than the HRNORMAL line. In addition, females were smaller than males in all metrics. Finally, there was no significant sex‐by‐line interaction for either body size metrics or centroid size, indicating no differential sexual dimorphism patterns in these variables between lines.

Results of MANOVAs showed that sex and line, but not body mass, had a significant effect on sacral shape, and there was no significant sex‐by‐line interaction. Further, we calculated a proxy measurement of sacral density using a ratio of sacral mass to sacral centroid size. ANOVAs showed a significant effect of sex, line, and the sex‐by‐line interaction, with females showing a greater mean bone density than males (a result opposite that found in a similar proxy metric in the os coxae). Overall, these results support the hypothesis that sacral morphology is influenced by sex, selection for high locomotor activity, and the presence of the mini‐muscle mutation in a complex manner, which affects specific skeletal elements in different ways.

Support or Funding Information

Murdock Charitable Trust
Optimization of technical photographic variables to assess newborn length using photographic imaging
Authors: Orozco Monica N. , Gwaltney Rebecca , Solomons Noel W.
Published: November 2023

Background

In the past we explored the use of standardized photographic images as a potential method to measure length in newborns, which showed corrigible limitations in accuracy.

Objective

To refine a photographic technique used to assess newborn anthropometry by studying the effect of several technical photographic variables on intrinsic error, using inanimate baby models.

Methods

Vertical (25, 50, 75, 100 and 125 cm) and horizontal (left, center and right) camera displacements, reference object size (5, 10, 20 and 25 cm), camera type (digital vs smartphone), and zoom magnification (pre vs post) were varied to optimize length accuracy from the photographic image. Total length from the images was calculated by adding up the head+trunk plus upper‐ and lower‐leg segments of the models, measured in mm on a paper print‐out, computer or smartphone screen, and then converted to actual length in cm in reference to the object. These were compared to the gold standard infantometer measurements for accuracy.

Results

Increasing focal length reduces error, with an optimal height at 1 m (0.07% error, p<0.001). Camera must be centered over a focal point equidistant to the baby and reference bar to minimize error (0.01%, p<0.001). Camera optics impact error significantly (p=0.018). Variance in procedures for zoom and in reference bar length do not appear to significantly minimize error.

Conclusion

Thus, technical photographic variables can be optimized to minimize estimated length error in inanimate model figures, promising a new, valid and comfortable camera‐based technique for assessing birth‐length in newborns.
Assessment of Myocardial Architecture Depends on Imaging DTMRI Parameters
Authors: Agger Peter , Laustsen Christoffer , Hjortdal Vibeke , Pedersen Michael
Published: November 2023

Background

Diffusion tensor magnetic resonance imaging (DTMRI) is widely used when assessing the orientation of cardiomyocytes in the heart. Three important parameters are obtained from DTMRI in order to define the myocardial anatomical substructures: fractional anisotropy (FA), mean diffusivity (MD), and helical angle (HA). The aim of this study was to demonstrate the effect of DTMRI sequence parameters: averaging, anisotropic resolution and number of diffusion‐weighted directions, on FA, MD and HA.

Methods

Health adult porcine hearts were harvested, formalin‐fixed, and a transmural biopsy of the left ventricular free wall was sampled and positioned in a 9.4 T MRI system. Five different DTMRI examinations were conducted: 1) with 6 predefined gradient directions, 2) with 30 directions, 3) with 6 directions and 2 averages, 4+5) with 6 and 30 directions, but with double slice thickness rendering the voxels anisotropic. All other DTMRI imaging parameters were kept constant. Differences in FA, MD and HA were analysed using ANOVA statistics.

Results

MD showed only minor non‐significant differences between groups. FA was decreased when using 30 diffusion directions (0.25±0.08) as compared with 6 directions (0.33±0.13), p<0.001. Helical angulations as compared using Bland‐Altman plots (Fig. 1) confirmed this finding revealing a variance indicative of low precision when using only 6 directions. Tractographies based on only 6 directions were less smooth and shorter when compared with 30 directions (Fig. 2).

Conclusions

This DTMRI study revealed that fewer gradient directions resulted in deterioration of the image quality, increasing the degree of averaging does not compensate for this. Introduction of anisotropic voxels on the other hand did not alter FA, MD or HA significantly. The results of this study are of importance when designing DTMRI protocols for the purpose of investigating myocardial microanatomy. We emphasize that interpretation of DTMRI results depends on the number of predefined diffusion directions.

Support or Funding Information

This work is supported by the Danish Children Heart Foundation.
Using CT Scans to Assess Early Postnatal Development of the Bony Eustachian Tube and Hyolaryngeal Apparatus: A Test of Reliability
Authors: Meaike Joshua , Gupta Anmol , Pagano Anthony , Curcio Daniella Franco , Som Peter , Laitman Jeffrey T.
Published: November 2023

Human infants, like non‐human primates, can breathe and swallow simultaneously, due to similarities in the anatomy of the aerodigestive tract (ADT). Morphometric studies lack standardized methods to investigate the descent of the hyolaryngeal apparatus in relation to the skull base and bony Eustachian tube – a process taking place throughout the first three years of postnatal life. This study tests the hypothesis that 3D landmark coordinates taken on sagittal CT scans can be reliably used to assess ADT and craniofacial structures via 3D geometric morphometrics. We used the computer program Osirix® to identify 14 landmarks on head and neck sagittal CT scans obtained from 22 monkeys (Macaca mulatta) as a model to test accuracy. After four training sessions on images apart from the study sample, two observers assessed the study sample. Each observer performed three assessments per specimen and no specimen was evaluated twice in the same day. We used Generalized Procrustes Analysis, involving optimal superimposition and scaling by Centroid Size, and measured the procrustes distances to interpret data. Inter‐observer errors were significantly high (> 5%), indicating that plotting landmarks on sagittal CTs allows for low reproducibility of measurements via 3D analysis. ANOVA of inter‐observer distances per landmark yielded a significant result (p<0.0001), indicating that some landmarks are less reliable, and a series of t‐tests with Bonferroni‐Dunn adjustment revealed that the craniometric point Prosthion was the least accurate (p<0.05). Tracking the descent of the hyolaryngeal complex relative to craniofacial structures in early postnatal life requires a careful methodological approach. This study indicates that using 3D landmarks obtained from CT sagittal slices to ascertain measurements of the hyoid bone and craniofacial structures situated in different planes yields intrinsic errors of measurements that may jeopardize reproducibility of geometric morphometric analysis. Next step of this project is to use volume rendered 3D CT scans and collect 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
A Refined Study of the Effect of Cadaver Dissection on Written and Practical Gross Anatomy Test Scores
Authors: Olivieri Marion Pace , Hurley Mary Ida , Gervasi Megan E , Olivieri Nina Ruthie , Rokitka Elizabeth M , Georger Lesley , Bistulfi Gaia
Published: November 2023

Since 2010, over 425 Italian medical students participated in D'Youville College's (DYC's) Giovanni Mazzotti Anatomy Conference (GMAC), named in honor of the late president of the Medical School of Bologna and the Italian Anatomy Society. In Italy, students rarely dissect cadavers. Instead, models, drawings, and computer‐generated images are utilized. Conference participants were selected by their professors at their corresponding Italian medical universities for their excellent anatomy competency and proficiency in English.

After careful review of the previous five years of data from similar populations, modifications were made to improve data collection and validate results. For this analysis, the written examinations were scrutinized by faculty in the US and Italy for proper word choice and grammar. Exams were available to each student in both English and Italian. The written exams were identical for pre‐ and post‐testing. The practical exams contained identical content for pre‐ and post‐testing, utilizing different cadavers and a re‐arrangement of question order. Results, including scores, were only provided to the students after completion of the conference. Data analysis focused on comparing learning in three specific areas comprising V (viscera), H (head and neck) and E (extremities). After ~100 hours of available laboratory time, pre‐ and post‐examination results were compared. On average, a significant improvement was observed in individual written exam scores by 9% (n=60; p<0.001), practical knowledge scores increased 23% (n=60; p<0.001) with combined anatomical knowledge scores averaging a 16% increase (n=60; p<0.001). Overall, the cadaver dissection experience increased the practical as well as theoretical knowledge of these elite high performing medical students.

We expect this collaboration to continue providing a more comprehensive analysis. We thank Todd Stevens and Russ Gullekson for their work with the Italian students in the anatomy laboratory. We also thank our collaborators, Professors Falconi & Manzoli (U of Bologna), Zecchi & Orlandini (U of Florence), Papa (U of Naples), Nori (U of Salerno), Sette (Rome's Tor Vergata) and Forni (U of Pisa).

Support or Funding Information

Supported by the GMAC and approved through the IRB of DYC.
A Comparison of Student Approach to Learning Between Dissection‐ and Prosection‐based Undergraduate Human Anatomy Courses
Authors: McWatt Sean C. , Newton Genevieve S. , Jadeski Lorraine C.
Published: November 2023

Human anatomy is among the oldest and most thoroughly studied sciences in modern history. In recent years, the focus of the field has become largely pedagogical, sparking debates on education and the instructional approaches that best facilitate deep‐learning and student understanding. The Undergraduate Human Anatomy Program at the University of Guelph features both dissection‐ and prosection‐based human anatomy courses in the third‐year of the Human Kinetics and Bio‐Medical Science majors. Students enrolled in these courses attend the same lectures, but one cohort participates in a dissection‐based laboratory, whereas the other participates in a prosection‐based laboratory session once per week. The University of Guelph is a learner‐centred institution; thus, a continuous effort to improve the student learning experience while maintaining the efficient and effective delivery of course content is of primary focus for the program. Literature suggests that the most effective method of anatomy instruction is a multifaceted approach that provides students with various resources that they may use to build a deeper understanding of the human body. Accordingly, supplemental teaching modalities are being explored at the University of Guelph to promote deep‐learning and improve the overall educational experience for human anatomy students. The objective of this study was to compare learning approach, performance, and course satisfaction between the two aforementioned cohorts of third‐year human anatomy students so that supplemental teaching modalities may be designed to target potential shortcomings of the program. Participating students completed surveys to collect demographic data (gender, age, program of study, etc.), learning approach (Revised Two‐factor Study Process Questionnaire), and perceived course experience (Course Experience Questionnaire) measures prior to their first laboratory and after the completion of the course. Preliminary results demonstrate an overall shift toward a deeper learning approach taken by students after the completion of the course and a generally positive perceived course experience. These findings suggest that participation in a dissection‐ or prosection‐based undergraduate human anatomy course promotes deep‐learning and is considered by students to be beneficial to their educational experience.
A Kinetic Model for Learning Gross Anatomy
Authors: Malone Erica Renee , Pine Michelle , Bingham Glenda
Published: November 2023

Many different types of visual aids have been proven valuable in teaching gross anatomy. Diagrams, illustrations, cadavers, and physical models are all common teaching aids in gross anatomy courses. While these types of visual aids are quite useful for identifying structures or understanding one structure's spatial relationship to another, these visual aids are incapable of demonstrating movement, a concept that is critical to understanding the practical applications of gross anatomy. In order to create a model capable of demonstrating movement, knowledge of concepts from disciplines including design, sculpture, architecture, and simple physics should be employed. Using this interdisciplinary approach to demonstrate movement allows for more valuable tools for learning and teaching gross anatomy. In order to test this concept, a design for an interactive kinetic model of the canine thoracic limb was created. Once a basic design for the model was conceived, many different materials were tested for their ability to mimic anatomical structures such as bones, ligaments, tendons, and muscles. These materials were then used to build a model complete with simulations of all relevant anatomical structures involved in movement. Once a preliminary iteration of the model was successfully constructed, students enrolled in Biomedical Anatomy at Texas A&M University's College of Veterinary Medicine and Biomedical Sciences were provided multiple opportunities to interact with the model. Observing the students’ interactions with the model gave us the opportunity to evaluate the design's ability to visually demonstrate proper movement of the thoracic limb. This preliminary iteration of the model, while valuable in proving the capabilities of the design, also proved some of the materials were inadequate. A second iteration of the model was then constructed using new, more durable, materials. Students were again allowed and encouraged to interact with the model, even using the model to complete an in‐lab assignment. After interacting with the model and being allowed access to the model for studying purposes, outside of assigned lab and lecture periods, these students were asked to fill out an anonymous questionnaire evaluating their perceived efficiency of the model as a tool for learning. Analysis of these questionnaires revealed that the vast majority of students found the model helpful with at least one concept related to movement. Further iterations of this kinetic model will include improvements to movement capabilities and material durability. Kinetic models for other relevant areas such as the pelvic limb, as well as models for equine, bovine, caprine, and other species are possible areas of research for the kinetic anatomical model.

Support or Funding Information

TAMU Summer 2012 Faculty Institute “Flipping Your Course”
ARE PROSECTIONS AN EFFECTIVE SUPPLEMENTAL TOOL FOR IMPROVING STUDENTS’ KNOWLEDGE OF NECK ANATOMY?
Authors: ALSHEHRY SAMI , Sedlmayr Jayc , Cork John
Published: November 2023

Introduction

The neck is a complex area that can be difficult for students to understand. Although cadaver dissection is still the best way to teach anatomy there are many other tools that can be used to help students understand neck anatomy. One of these tools is prosection.

Aim

To evaluate students’ understanding of neck anatomy after studying prosections of the neck.

Materials and methods

63 first‐year dental students at LSUHSC were involved in this study during their head and neck anatomy course. The students took a quiz (pre‐test) on their knowledge of neck anatomy. Then, they were provided access to 8 neck prosections for 3 full labs (total 9 hours). Labeled photos for these prosections were placed next to each prosection and instructor was available to answer students’ questions. Finally, students answered the same quiz (post‐test). The quiz also included demographic data questions.

Results

63 responses were collected each time. The mean score on the pre‐test was 62.1% and mean score for the post‐test was 65.9% (this difference was statistically significant at p = 0.0003). When asked whether they had studied the prosections 24 (38%) of the students said no. When comparing the mean scores of the pre‐test and post‐test for the group who didn't study the prosections, the mean difference was insignificant (p‐value= 0.2). For the group who did study the prosections, the difference in scores was significant (p‐value=0.0004).

Conclusion

We found in this study that the use of prosections will improve students’ understanding of neck anatomy.

Support or Funding Information

LSUHSC‐NO
The Utility of Cadaver‐Based Approaches for the Teaching of Human Anatomy: A Survey of British and Irish Anatomy Teachers
Authors: Balta Joy Y. , Cronin Michael , Cryan John F. , O'Mahony Siobhain M.
Published: November 2023

Human cadavers have been used for centuries to learn about the human body. Today they still represent a key anatomy learning tool in most Medical Schools. Using reality anatomy such as dissection and demonstrating using cadavers has been described as a superior way to create meaning. To prevent the decomposition of cadavers and to decrease any health risks, cadavers are embalmed using different chemicals. These chemicals can differentially alter the tissue of the human body which has led to the usage of different processes along the hard to soft‐fixed spectrum of preserved cadavers. However, it is currently unclear what is the perceived utility of the different preservation modalities within anatomy learning environments.

To this end we used a questionnaire based approach to gain a better insight into the opinion of anatomists on the use of preserved cadavers for the teaching of human anatomy. We focused on anatomy teachers in the United Kingdom and Ireland. From the 125 participating anatomists, 34.4% were medically qualified, 30.4% had a PhD in a non‐anatomical science and 22.4% had a PhD in an anatomical science, these figures include ten anatomists who had combinations of MD with the two other PhD qualifications. Anatomists with different background had different experiences. Table 1 shows the experiences of participating anatomist.

The main findings from the questionnaire were that 61.6% of participants agreed that hard‐fixed formalin cadavers accurately resemble features of a human body while 21.6% disagreed. Moreover, anatomists rated the teaching aids on how accurately resemble features of the human body as follows (Figure 1) : plastic models the least accurate followed by plastinated specimen, and hard fixed cadavers; soft preserved cadavers were considered to be the most accurate when it comes to resembling features of the human body. Friedman test was conducted followed by Post hoc analysis with Wilcoxon signed‐rank tests showing that there was a statistically significant difference in rating between the different teaching aids.

With different embalming solutions becoming more commercially available, it is important to remain unbiased and consider the best interest of education and research. Further research is required in order to investigate which techniques or methods provide better teaching tool for a range of anatomical teaching levels and for the sections of the body used in surgical training.

Experience of anatomists teaching in the U.K. and Ireland in surgery, teaching a cadaver based anatomy module, examining the tissue of dissected fresh cadavers and examining the tissue of dissected soft preserved cadavers.

Experience
Yes (%)

Surgery±
34.4%

Cadaver Teaching
98.4%

Examine Fresh Cadaver
52%

Examine Soft Preserved cadaver
56%

relevant to those who chose Medical Degree