1
|
Panagiotopoulou O, Robinson D, Iriarte-Diaz J, Ackland D, Taylor AB, Ross CF. Dynamic finite element modelling of the macaque mandible during a complete mastication gape cycle. Philos Trans R Soc Lond B Biol Sci 2023; 378:20220549. [PMID: 37839457 PMCID: PMC10577025 DOI: 10.1098/rstb.2022.0549] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Accepted: 09/14/2023] [Indexed: 10/17/2023] Open
Abstract
Three-dimensional finite element models (FEMs) are powerful tools for studying the mechanical behaviour of the feeding system. Using validated, static FEMs we have previously shown that in rhesus macaques the largest food-related differences in strain magnitudes during unilateral postcanine chewing extend from the lingual symphysis to the endocondylar ridge of the balancing-side ramus. However, static FEMs only model a single time point during the gape cycle and probably do not fully capture the mechanical behaviour of the jaw during mastication. Bone strain patterns and moments applied to the mandible are known to vary during the gape cycle owing to variation in the activation peaks of the jaw-elevator muscles, suggesting that dynamic models are superior to static ones in studying feeding biomechanics. To test this hypothesis, we built dynamic FEMs of a complete gape cycle using muscle force data from in vivo experiments to elucidate the impact of relative timing of muscle force on mandible biomechanics. Results show that loading and strain regimes vary across the chewing cycle in subtly different ways for different foods, something which was not apparent in static FEMs. These results indicate that dynamic three-dimensional FEMs are more informative than static three-dimensional FEMs in capturing the mechanical behaviour of the jaw during feeding by reflecting the asymmetry in jaw-adductor muscle activations during a gape cycle. This article is part of the theme issue 'Food processing and nutritional assimilation in animals'.
Collapse
Affiliation(s)
- Olga Panagiotopoulou
- Monash Biomedicine Discovery Institute, Department of Anatomy and Developmental Biology, Monash University, Melbourne, Victoria 3800, Australia
| | - Dale Robinson
- Department of Biomedical Engineering, University of Melbourne, Melbourne, Victoria 3053, Australia
| | - Jose Iriarte-Diaz
- Department of Biology, University of the South, Sewanee, TN 37383, USA
| | - David Ackland
- Department of Biomedical Engineering, University of Melbourne, Melbourne, Victoria 3053, Australia
| | - Andrea B. Taylor
- Department of Foundational Biomedical Sciences, Touro University California, Vallejo, CA 94592, USA
| | - Callum F. Ross
- Department of Organismal Biology and Anatomy, University of Chicago, Chicago, IL 60637, USA
| |
Collapse
|
2
|
Chivers S, Cleary A, Knowles R, Babu-Narayan SV, Simpson JM, Nashat H, Dimopoulos K, Gatzoulis MA, Wilson D, Prica M, Anthony J, Clift PF, Jowett V, Jenkins P, Khodaghalian B, Jones CB, Hardiman A, Head C, Miller O, Chung NA, Mahmood U, Bu'Lock FA, Ramcharan TK, Chikermane A, Shortland J, Tometzki A, Crossland DS, Reinhardt Z, Lewis C, Rittey L, Hares D, Panagiotopoulou O, Smith B, Najih L M, Bharucha T, Daubeney PE. COVID-19 in congenital heart disease (COaCHeD) study. Open Heart 2023; 10:e002356. [PMID: 37460271 PMCID: PMC10357297 DOI: 10.1136/openhrt-2023-002356] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Accepted: 06/23/2023] [Indexed: 07/20/2023] Open
Abstract
BACKGROUND COVID-19 has caused significant worldwide morbidity and mortality. Congenital heart disease (CHD) is likely to increase vulnerability and understanding the predictors of adverse outcomes is key to optimising care. OBJECTIVE Ascertain the impact of COVID-19 on people with CHD and define risk factors for adverse outcomes. METHODS Multicentre UK study undertaken 1 March 2020-30 June 2021 during the COVID-19 pandemic. Data were collected on CHD diagnoses, clinical presentation and outcomes. Multivariable logistic regression with multiple imputation was performed to explore predictors of death and hospitalisation. RESULTS There were 405 reported cases (127 paediatric/278 adult). In children (age <16 years), there were 5 (3.9%) deaths. Adjusted ORs (AORs) for hospitalisation in children were significantly lower with each ascending year of age (OR 0.85, 95% CI 0.75 to 0.96 (p<0.01)). In adults, there were 24 (8.6%) deaths (19 with comorbidities) and 74 (26.6%) hospital admissions. AORs for death in adults were significantly increased with each year of age (OR 1.05, 95% CI 1.01 to 1.10 (p<0.01)) and with pulmonary arterial hypertension (PAH; OR 5.99, 95% CI 1.34 to 26.91 (p=0.02)). AORs for hospitalisation in adults were significantly higher with each additional year of age (OR 1.03, 95% CI 1.00 to 1.05 (p=0.04)), additional comorbidities (OR 3.23, 95% CI 1.31 to 7.97 (p=0.01)) and genetic disease (OR 2.87, 95% CI 1.04 to 7.94 (p=0.04)). CONCLUSIONS Children were at low risk of death and hospitalisation secondary to COVID-19 even with severe CHD, but hospital admission rates were higher in younger children, independent of comorbidity. In adults, higher likelihood of death was associated with increasing age and PAH, and of hospitalisation with age, comorbidities and genetic disease. An individualised approach, based on age and comorbidities, should be taken to COVID-19 management in patients with CHD.
Collapse
Affiliation(s)
- Sian Chivers
- Department of Congenital Cardiology, Royal Brompton & Harefield NHS Foundation Trust, London, UK
- Department of Congenital Cardiology, Evelina London Children's Hospital, London, UK
| | - Aoife Cleary
- Department of Congenital Cardiology, Evelina London Children's Hospital, London, UK
- Department of Congenital Cardiology, Great Ormond Street Hospital for Children, London, UK
| | - Rachel Knowles
- Department of Public Health Medicine, Great Ormond Street Hospital for Children, London, UK
- UCL Great Ormond Street Institute of Child Health Population Policy and Practice, London, UK
| | - Sonya V Babu-Narayan
- Department of Congenital Cardiology, Royal Brompton & Harefield NHS Foundation Trust, London, UK
- Imperial College London, London, UK
| | - John M Simpson
- Department of Congenital Cardiology, Evelina London Children's Hospital, London, UK
| | - Heba Nashat
- Department of Adult Congenital heart disease, Royal Brompton & Harefield NHS Foundation Trust, London, UK
| | - Konstantinos Dimopoulos
- Department of Adult Congenital heart disease, Royal Brompton & Harefield NHS Foundation Trust, London, UK
| | - Michael A Gatzoulis
- Department of Adult Congenital heart disease, Royal Brompton & Harefield NHS Foundation Trust, London, UK
| | - Dirk Wilson
- Department of Congenital Cardiology, University Hospital of Wales Healthcare NHS Trust, Cardiff, UK
| | - Milos Prica
- Department of Adult Congenital heart disease, Leeds Teaching Hospitals NHS Trust, Leeds, UK
| | - James Anthony
- Department of Adult Congenital heart disease, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK
| | - Paul F Clift
- Department of Adult Congenital heart disease, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK
| | - Victoria Jowett
- Department of Congenital Cardiology, Great Ormond Street Hospital for Children, London, UK
| | - Petra Jenkins
- Department of Adult Congenital heart disease, Liverpool Heart and Chest Hospital NHS Foundation Trust, Liverpool, UK
| | - Bernadette Khodaghalian
- Department of Congenital Cardiology, Alder Hey Children's NHS Foundation Trust, Liverpool, UK
| | - Caroline B Jones
- Department of Congenital Cardiology, Alder Hey Children's NHS Foundation Trust, Liverpool, UK
| | - Antonia Hardiman
- Department of Adult Congenital heart disease, Norfolk and Norwich University Hospital NHS Trust, Norwich, UK
| | - Catherine Head
- Department of Adult Congenital heart disease, Norfolk and Norwich University Hospital NHS Trust, Norwich, UK
| | - Owen Miller
- Department of Congenital Cardiology, Evelina London Children's Hospital, London, UK
| | - Natali Ay Chung
- Department of Adult Congenital heart disease, St Thomas' Hospital, London, UK
| | - Umar Mahmood
- Department of Congenital Cardiology, Glenfield Hospital East Midlands Congenital Heart Centre, Leicester, UK
| | - Frances A Bu'Lock
- Department of Congenital Cardiology, Glenfield Hospital East Midlands Congenital Heart Centre, Leicester, UK
| | - Tristan Kw Ramcharan
- Department of Congenital Cardiology, Birmingham Women's and Children's NHS Foundation Trust, Birmingham, UK
| | - Ashish Chikermane
- Department of Congenital Cardiology, Birmingham Children's Hospital NHS Foundation Trust, Birmingham, UK
| | - Jennifer Shortland
- Department of Congenital Cardiology, Bristol Royal Hospital for Children, Bristol, UK
| | - Andrew Tometzki
- Department of Congenital Cardiology, Bristol Royal Hospital for Children, Bristol, UK
| | - David S Crossland
- Department of Congenital Cardiology, Freeman Hospital Cardiothoracic Centre, Newcastle upon Tyne, UK
| | - Zdenka Reinhardt
- Department of Congenital Cardiology, Freeman Hospital Cardiothoracic Centre, Newcastle upon Tyne, UK
| | - Clive Lewis
- Department of Adult Congenital heart disease, Papworth Hospital, Cambridge, UK
| | - Leila Rittey
- Department of Congenital Cardiology, Leeds Children's Hospital, Leeds, UK
| | - Dominic Hares
- Department of Congenital Cardiology, Leeds Teaching Hospitals NHS Trust, Leeds, UK
| | - Olga Panagiotopoulou
- Department of Congenital Cardiology, Royal Hospital for Sick Children Yorkhill, Glasgow, UK
| | - Benjamin Smith
- Department of Congenital Cardiology, Royal Hospital for Sick Children Yorkhill, Glasgow, UK
| | - Muhammad Najih L
- Department of Congenital Cardiology, Southampton Children's Hospital, Southampton, UK
| | - Tara Bharucha
- Department of Congenital Cardiology, Southampton Children's Hospital, Southampton, UK
| | - Piers Ef Daubeney
- Department of Congenital Cardiology, Royal Brompton and Harefield NHS Trust, London, UK
| |
Collapse
|
3
|
Haravu PN, Gonzalez M, Nathan SL, Ross CF, Panagiotopoulou O, Reid RR. The biomechanics of chewing and suckling in the infant: A potential mechanism for physiologic metopic suture closure. PLoS Comput Biol 2023; 19:e1011227. [PMID: 37347795 DOI: 10.1371/journal.pcbi.1011227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2023] [Accepted: 05/30/2023] [Indexed: 06/24/2023] Open
Abstract
Craniosynostosis is a condition with neurologic and aesthetic sequelae requiring invasive surgery. Understanding its pathobiology requires familiarity with the processes underlying physiologic suture closure. Animal studies have shown that cyclical strain from chewing and suckling influences the closure of cranial vault sutures, especially the metopic, an important locus of craniosynostosis. However, there are no human data correlating strain patterns during chewing and suckling with the physiologically early closure pattern of the metopic suture. Furthermore, differences in craniofacial morphology make it challenging to directly extrapolate animal findings to humans. Eight finite-element analysis (FEA) models were built from craniofacial computer tomography (CT) scans at varying stages of metopic suture closure, including two with isolated non-syndromic metopic craniosynostosis. Muscle forces acting on the cranium during chewing and suckling were simulated using subject-specific jaw muscle cross-sectional areas. Chewing and suckling induced tension at the metopic and sagittal sutures, and compressed the coronal, lambdoid, and squamous sutures. Relative to other cranial vault sutures, the metopic suture experienced larger magnitudes of axial strain across the suture and a lower magnitude of shear strain. Strain across the metopic suture decreased during suture closure, but other sutures were unaffected. Strain patterns along the metopic suture mirrored the anterior to posterior sequence of closure: strain magnitudes were highest at the glabella and decreased posteriorly, with minima at the nasion and the anterior fontanelle. In models of physiologic suture closure, increased degree of metopic suture closure correlated with higher maximum principal strains across the frontal bone and mid-face, a strain regime not observed in models of severe metopic craniosynostosis. In summary, our work provides human evidence that bone strain patterns from chewing and suckling correlate with the physiologically early closure pattern of the metopic suture, and that deviations from physiologic strain regimes may contribute to clinically observed craniofacial dysmorphism.
Collapse
Affiliation(s)
- Pranav N Haravu
- Pritzker School of Medicine, University of Chicago, Illinois, United States of America
| | - Miguel Gonzalez
- Pritzker School of Medicine, University of Chicago, Illinois, United States of America
| | - Shelby L Nathan
- Section of Plastic & Reconstructive Surgery, University of Chicago, Illinois, United States of America
| | - Callum F Ross
- Department of Organismal Biology and Anatomy, University of Chicago, Chicago, Illinois, United States of America
| | - Olga Panagiotopoulou
- Monash Biomedicine Discovery Institute, Department of Anatomy and Developmental Biology, Monash University, Victoria, Australia
| | - Russell R Reid
- Section of Plastic & Reconstructive Surgery, University of Chicago, Illinois, United States of America
| |
Collapse
|
4
|
Semple BD, Panagiotopoulou O. Cranial Bone Changes Induced by Mild Traumatic Brain Injuries: A Neglected Player in Concussion Outcomes? Neurotrauma Rep 2023; 4:396-403. [PMID: 37350792 PMCID: PMC10282977 DOI: 10.1089/neur.2023.0025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/24/2023] Open
Abstract
Mild traumatic brain injuries (TBIs), particularly when repetitive in nature, are increasingly recognized to have a range of significant negative implications for brain health. Much of the ongoing research in the field is focused on the neurological consequences of these injuries and the relationship between TBIs and long-term neurodegenerative conditions such as chronic traumatic encephalopathy and Alzheimer's disease. However, our understanding of the complex relationship between applied mechanical force at impact, brain pathophysiology, and neurological function remains incomplete. Past research has shown that mild TBIs, even below the threshold that results in cranial fracture, induce changes in cranial bone structure and morphology. These structural and physiological changes likely have implications for the transmission of mechanical force into the underlying brain parenchyma. Here, we review this evidence in the context of the current understanding of bone mechanosensitivity and the consequences of TBIs or concussions. We postulate that heterogeneity of the calvarium, including differing bone thickness attributable to past impacts, age, or individual variability, may be a modulator of outcomes after subsequent TBIs. We advocate for greater consideration of cranial responses to TBI in both experimental and computer modeling of impact biomechanics, and raise the hypothesis that calvarial bone thickness represents a novel biomarker of brain injury vulnerability post-TBI.
Collapse
Affiliation(s)
- Bridgette D. Semple
- Department of Neuroscience, Monash University, Prahran, Victoria, Australia
- Department of Neurology, Alfred Health, Prahran, Victoria, Australia
- Department of Medicine (Royal Melbourne Hospital), University of Melbourne, Parkville, Victoria, Australia
| | - Olga Panagiotopoulou
- Monash Biomedicine Discovery Institute, Department of Anatomy and Developmental Biology, Monash University, Clayton, Victoria, Australia
| |
Collapse
|
5
|
Panagiotopoulou O, Iriarte-Diaz J, Abraha HM, Taylor AB, Wilshin S, Dechow PC, Ross CF. Corrigendum to "Biomechanics of the mandible of Macaca mulatta during the power stroke of mastication: Loading, deformation, and strain regimes and the impact of food type" [Journal of Human Evolution 147 (2020) 102865]. J Hum Evol 2023; 179:103367. [PMID: 37084622 PMCID: PMC10627476 DOI: 10.1016/j.jhevol.2023.103367] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/23/2023]
Affiliation(s)
- Olga Panagiotopoulou
- Department of Anatomy & Developmental Biology, Monash Biomedicine Discovery Institute, Faculty of Medicine Nursing and Health Sciences, Monash University, Clayton, Melbourne, Victoria, 3800, Australia.
| | - Jose Iriarte-Diaz
- Department of Biology, University of the South, Sewanee, TN, 37383, USA
| | - Hyab Mehari Abraha
- Department of Anatomy & Developmental Biology, Monash Biomedicine Discovery Institute, Faculty of Medicine Nursing and Health Sciences, Monash University, Clayton, Melbourne, Victoria, 3800, Australia
| | - Andrea B Taylor
- Department of Basic Science, Touro University, CA, 94592, USA
| | - Simon Wilshin
- Comparative Biomedical Sciences, The Royal Veterinary College, Hawkshead Lane, Herts, AL97TA, UK
| | - Paul C Dechow
- Department of Biomedical Sciences, Texas A&M University College of Dentistry, Dallas, TX, 75246, USA
| | - Callum F Ross
- Department of Organismal Biology and Anatomy, University of Chicago, Chicago, IL, 60637, USA.
| |
Collapse
|
6
|
Smith AL, Davis J, Panagiotopoulou O, Taylor AB, Robinson C, Ward CV, Kimbel WH, Alemseged Z, Ross CF. Does the model reflect the system? When two-dimensional biomechanics is not 'good enough'. J R Soc Interface 2023; 20:20220536. [PMID: 36695017 PMCID: PMC9874278 DOI: 10.1098/rsif.2022.0536] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Models are mathematical representations of systems, processes or phenomena. In biomechanics, finite-element modelling (FEM) can be a powerful tool, allowing biologists to test form-function relationships in silico, replacing or extending results of in vivo experimentation. Although modelling simplifications and assumptions are necessary, as a minimum modelling requirement the results of the simplified model must reflect the biomechanics of the modelled system. In cases where the three-dimensional mechanics of a structure are important determinants of its performance, simplified two-dimensional modelling approaches are likely to produce inaccurate results. The vertebrate mandible is one among many three-dimensional anatomical structures routinely modelled using two-dimensional FE analysis. We thus compare the stress regimes of our published three-dimensional model of the chimpanzee mandible with a published two-dimensional model of the chimpanzee mandible and identify several fundamental differences. We then present a series of two-dimensional and three-dimensional FE modelling experiments that demonstrate how three key modelling parameters, (i) dimensionality, (ii) symmetric geometry, and (iii) constraints, affect deformation and strain regimes of the models. Our results confirm that, in the case of the primate mandible (at least), two-dimensional FEM fails to meet this minimum modelling requirement and should not be used to draw functional, ecological or evolutionary conclusions.
Collapse
Affiliation(s)
- Amanda L. Smith
- Department of Organismal Biology and Anatomy, University of Chicago, 1027 East 57th St, Chicago, IL 60637, USA,Department of Anatomy, Pacific Northwest University of Health Sciences, Yakima, WA 90981, USA
| | - Julian Davis
- Department of Engineering, University of Southern Indiana, 8600 University Blvd, Evansville, IN 47712, USA
| | - Olga Panagiotopoulou
- Department of Anatomy & Developmental Biology, Monash Biomedicine Discovery Institute, Faculty of Medicine Nursing and Health Sciences, Monash University, Clayton, Melbourne, Victoria 3800, Australia
| | | | - Chris Robinson
- Department of Biological Sciences, Bronx Community College, Bronx, NY 10453, USA,Doctoral Program in Anthropology, The Graduate Center, City University of New York, New York, NY 10016, USA
| | - Carol V. Ward
- Department of Pathology & Anatomical Sciences, One Hospital Drive, University of Missouri, Columbia, MO 65212, USA
| | - William H. Kimbel
- School of Human Evolution and Social Change, Arizona State University, Tempe, AZ 85287-4101, USA
| | - Zeresenay Alemseged
- Department of Organismal Biology and Anatomy, University of Chicago, 1027 East 57th St, Chicago, IL 60637, USA
| | - Callum F. Ross
- Department of Anatomy, Pacific Northwest University of Health Sciences, Yakima, WA 90981, USA
| |
Collapse
|
7
|
Haravu PN, Abraha HM, Shang M, Iriarte-Diaz J, Taylor AB, Reid RR, Ross CF, Panagiotopoulou O. Macaca mulatta is a good model for human mandibular fixation research. R Soc Open Sci 2022; 9:220438. [PMID: 36405636 PMCID: PMC9667141 DOI: 10.1098/rsos.220438] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Accepted: 10/26/2022] [Indexed: 06/16/2023]
Abstract
Biomechanical and clinical studies have yet to converge on the optimal fixation technique for angle fractures, one of the most common and controversial fractures in terms of fixation approach. Prior pre-clinical studies have used a variety of animal models and shown abnormal strain environments exacerbated by less rigid (single-plate) Champy fixation and chewing on the side opposite the fracture (contralateral chewing). However, morphological differences between species warrant further investigation to ensure that these findings are translational. Here we present the first study to use realistically loaded finite-element models to compare the biomechanical behaviour of human and macaque mandibles pre- and post-fracture and fixation. Our results reveal only small differences in deformation and strain regimes between human and macaque mandibles. In the human model, more rigid biplanar fixation better approximated physiologically healthy global bone strains and moments around the mandible, and also resulted in less interfragmentary strain than less rigid Champy fixation. Contralateral chewing exacerbated deviations in strain, moments and interfragmentary strain, especially under Champy fixation. Our pre- and post-fracture fixation findings are congruent with those from macaques, confirming that rhesus macaques are excellent animal models for biomedical research into mandibular fixation. Furthermore, these findings strengthen the case for rigid biplanar fixation over less rigid one-plate fixation in the treatment of isolated mandibular angle fractures.
Collapse
Affiliation(s)
- Pranav N. Haravu
- Department of Surgery, Section of Plastic Surgery, The University of Chicago Medical Centre, Chicago, IL, USA
| | - Hyab Mehari Abraha
- Monash Biomedicine Discovery Institute, Department of Anatomy and Developmental Biology, Monash University, Victoria, Australia
| | - Michelle Shang
- Department of Surgery, Section of Plastic Surgery, The University of Chicago Medical Centre, Chicago, IL, USA
| | - Jose Iriarte-Diaz
- Department of Biology, The University of the South, Sewanee, TN, USA
| | | | - Russell R. Reid
- Department of Surgery, Section of Plastic Surgery, The University of Chicago Medical Centre, Chicago, IL, USA
| | - Callum F. Ross
- Department of Organismal Biology and Anatomy, University of Chicago, Chicago, IL, USA
| | - Olga Panagiotopoulou
- Monash Biomedicine Discovery Institute, Department of Anatomy and Developmental Biology, Monash University, Victoria, Australia
| |
Collapse
|
8
|
Pollock TI, Panagiotopoulou O, Hocking DP, Evans AR. Taking a stab at modelling canine tooth biomechanics in mammalian carnivores with beam theory and finite-element analysis. R Soc Open Sci 2022; 9:220701. [PMID: 36300139 PMCID: PMC9579775 DOI: 10.1098/rsos.220701] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Accepted: 09/30/2022] [Indexed: 06/16/2023]
Abstract
Canine teeth are vital to carnivore feeding ecology, facilitating behaviours related to prey capture and consumption. Forms vary with specific feeding ecologies; however, the biomechanics that drive these relationships have not been comprehensively investigated. Using a combination of beam theory analysis (BTA) and finite-element analysis (FEA) we assessed how aspects of canine shape impact tooth stress, relating this to feeding ecology. The degree of tooth lateral compression influenced tolerance of multidirectional loads, whereby canines with more circular cross-sections experienced similar maximum stresses under pulling and shaking loads, while more ellipsoid canines experienced higher stresses under shaking loads. Robusticity impacted a tooth's ability to tolerate stress and appears to be related to prey materials. Robust canines experience lower stresses and are found in carnivores regularly encountering hard foods. Slender canines experience higher stresses and are associated with carnivores biting into muscle and flesh. Curvature did not correlate with tooth stress; however, it did impact bending during biting. Our simulations help identify scenarios where canine forms are likely to break and pinpoint areas where this breakage may occur. These patterns demonstrate how canine shape relates to tolerating the stresses experienced when killing and feeding, revealing some of the form-function relationships that underpin mammalian carnivore ecologies.
Collapse
Affiliation(s)
- Tahlia I. Pollock
- School of Biological Sciences, Monash University, Clayton 3800, Australia
| | - Olga Panagiotopoulou
- Monash Biomedicine Discovery Institute, Department of Anatomy & Developmental Biology, Monash University, Clayton 3800, Australia
| | - David P. Hocking
- School of Biological Sciences, Monash University, Clayton 3800, Australia
- Zoology, Tasmanian Museum and Art Gallery, Hobart, Australia
| | - Alistair R. Evans
- School of Biological Sciences, Monash University, Clayton 3800, Australia
- Geosciences, Museums Victoria, Melbourne, Victoria, Australia
| |
Collapse
|
9
|
Jannel A, Salisbury SW, Panagiotopoulou O. Softening the steps to gigantism in sauropod dinosaurs through the evolution of a pedal pad. Sci Adv 2022; 8:eabm8280. [PMID: 35947665 PMCID: PMC9365286 DOI: 10.1126/sciadv.abm8280] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Accepted: 06/27/2022] [Indexed: 06/15/2023]
Abstract
How sauropod dinosaurs were able to withstand the forces associated with their immense size represents one of the most challenging biomechanical scenarios in the evolution of terrestrial tetrapods, but also one lacking robust biomechanical testing. Here, we use finite element analyses to quantify the biomechanical effects of foot skeletal postures with and without the presence of a soft tissue pad in sauropodomorphs. We find that none of the models can maintain bone stresses that fall within optimal bone safety factors in the absence of a soft tissue pad. Our findings suggest that a soft tissue pad in sauropods would have reduced bone stresses by combining the mechanical advantages of a functionally plantigrade foot with the plesiomorphic skeletally digitigrade saurischian condition. The acquisition of a developed soft tissue pad by the Late Triassic-Early Jurassic may represent one of the key adaptations for the evolution of gigantism that has become emblematic of these dinosaurs.
Collapse
Affiliation(s)
- Andréas Jannel
- School of Biological Sciences, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Steven W. Salisbury
- School of Biological Sciences, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Olga Panagiotopoulou
- Monash Biomedicine Discovery Institute, Department of Anatomy and Developmental Biology, Monash University, Clayton, VIC 3800, Australia
| |
Collapse
|
10
|
Sinopidis X, Tsekoura E, Plotas P, Gkentzi D, Roupakias S, Fouzas S, Karatza A, Skaperda M, Panagiotopoulou O, Spyridakis I, Sakellaris G, Jelastopulu E. Healthcare workers' hand hygiene knowledge and compliance evaluation, in a Greek university hospital. Eur Rev Med Pharmacol Sci 2022; 26:5667-5675. [PMID: 36066138 DOI: 10.26355/eurrev_202208_29500] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
OBJECTIVE Healthcare associated infections affect both patients and employees, in terms of morbidity, mortality, and financial costs. Routine hand hygiene is the most important factor against this pestilence. Hand hygiene knowledge and compliance of healthcare workers are considered poor worldwide. Herein, we aimed to measure knowledge and compliance with hand hygiene of the healthcare workers at a university hospital. MATERIALS AND METHODS The "WHO hand hygiene knowledge questionnaire for healthcare workers" was translated in the Greek language, and was validated linguistically, culturally, and psychometrically. Reliability, content, construct, and convergent validity were measured. A survey on hand hygiene knowledge, and compliance, based on this questionnaire, was conducted on 439 employees. RESULTS The translated questionnaire presented good reliability, with Guttman's Lambda-6 evaluation (0.7). Content Validity Ratio was 84.6%. Confirmatory and exploratory factor analysis showed moderate construct validity. Convergent validity showed low correlation between the questionnaire items. Regarding the answers received, it was found that only 55.3% of the respondents received formal training on hand hygiene during the last three years prior to the study. Furthermore, 74.0% of them used alcohol-based solutions routinely. Only 54.3% of the participants presented an acceptable level of hand hygiene knowledge. CONCLUSIONS The translation and validation of the WHO questionnaire resulted in an acceptable, reliable, and valid instrument. The survey showed that hand hygiene is rather a matter of habit, than of knowledge, and that there is great need of more organized training.
Collapse
Affiliation(s)
- X Sinopidis
- Department of Pediatric Surgery, Department of Pediatrics, University of Patras School of Medicine, Patras, Greece.
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
11
|
Mehari Abraha H, Iriarte‐Diaz J, Reid RR, Ross CF, Panagiotopoulou O. Fracture Fixation Technique and Chewing Side Impact Jaw Mechanics in Mandible Fracture Repair. JBMR Plus 2021; 6:e10559. [PMID: 35079674 PMCID: PMC8770999 DOI: 10.1002/jbm4.10559] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Revised: 08/17/2021] [Accepted: 09/07/2021] [Indexed: 12/04/2022] Open
Abstract
Lower jaw (mandible) fractures significantly impact patient health and well‐being due to pain and difficulty eating, but the best technique for repairing the most common subtype—angle fractures—and rehabilitating mastication is unknown. Our study is the first to use realistic in silico simulation of chewing to quantify the effects of Champy and biplanar techniques of angle fracture fixation. We show that more rigid, biplanar fixation results in lower strain magnitudes in the miniplates, the bone around the screws, and in the fracture zone, and that the mandibular strain regime approximates the unfractured condition. Importantly, the strain regime in the fracture zone is affected by chewing laterality, suggesting that both fixation type and the patient's post‐fixation masticatory pattern—ipsi‐ or contralateral to the fracture— impact the bone healing environment. Our study calls for further investigation of the impact of fixation technique on chewing behavior. Research that combines in vivo and in silico approaches can link jaw mechanics to bone healing and yield more definitive recommendations for fixation, hardware, and postoperative rehabilitation to improve outcomes. © 2021 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.
Collapse
Affiliation(s)
- Hyab Mehari Abraha
- Monash Biomedicine Discovery Institute, Department of Anatomy and Developmental Biology Monash University Melbourne Australia
| | | | - Russell R Reid
- Department of Surgery, Section of Plastic Surgery The University of Chicago Medical Centre Chicago IL USA
| | - Callum F Ross
- Department of Organismal Biology and Anatomy University of Chicago Chicago IL USA
| | - Olga Panagiotopoulou
- Monash Biomedicine Discovery Institute, Department of Anatomy and Developmental Biology Monash University Melbourne Australia
| |
Collapse
|
12
|
Smith AL, Robinson C, Taylor AB, Panagiotopoulou O, Davis J, Ward CV, Kimbel WH, Alemseged Z, Ross CF. Comparative biomechanics of the Pan and Macaca mandibles during mastication: finite element modelling of loading, deformation and strain regimes. Interface Focus 2021; 11:20210031. [PMID: 34938438 PMCID: PMC8361577 DOI: 10.1098/rsfs.2021.0031] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/09/2021] [Indexed: 10/17/2023] Open
Abstract
The mechanical behaviour of the mandibles of Pan and Macaca during mastication was compared using finite element modelling. Muscle forces were calculated using species-specific measures of physiological cross-sectional area and scaled using electromyographic estimates of muscle recruitment in Macaca. Loading regimes were compared using moments acting on the mandible and strain regimes were qualitatively compared using maps of principal, shear and axial strains. The enlarged and more vertically oriented temporalis and superficial masseter muscles of Pan result in larger sagittal and transverse bending moments on both working and balancing sides, and larger anteroposterior twisting moments on the working side. The mandible of Pan experiences higher principal strain magnitudes in the ramus and mandibular prominence, higher transverse shear strains in the top of the symphyseal region and working-side corpus, and a predominance of sagittal bending-related strains in the balancing-side mandible. This study lays the foundation for a broader comparative study of Hominidae mandibular mechanics in extant and fossil hominids using finite element modelling. Pan's larger and more vertical masseter and temporalis may make it a more suitable model for hominid mandibular biomechanics than Macaca.
Collapse
Affiliation(s)
- Amanda L. Smith
- Department of Anatomy, Pacific Northwest University of Health Sciences, 200 University Parkway, Yakima, WA 98901, USA
- Department of Organismal Biology and Anatomy, University of Chicago, 1027 East 57th Street, Chicago, IL 60637, USA
| | - Chris Robinson
- Department of Biological Sciences, Bronx Community College, Bronx, NY 10453, USA
| | | | - Olga Panagiotopoulou
- Department of Anatomy and Developmental Biology, Monash Biomedicine Discovery Institute, Faculty of Medicine, Nursing and Health Sciences, Monash University, Clayton, Melbourne, Victoria 3800, Australia
| | - Julian Davis
- Department of Engineering, University of Southern Indiana, 8600 University Boulevard, Evansville, IN 47712, USA
| | - Carol V. Ward
- Department of Pathology and Anatomical Sciences, One Hospital Drive, University of Missouri, Columbia, MO 65212, USA
| | - William H. Kimbel
- School of Human Evolution and Social Change, Arizona State University, Tempe, AZ 85287-4101, USA
| | - Zeresenay Alemseged
- Department of Organismal Biology and Anatomy, University of Chicago, 1027 East 57th Street, Chicago, IL 60637, USA
| | - Callum F. Ross
- Department of Organismal Biology and Anatomy, University of Chicago, 1027 East 57th Street, Chicago, IL 60637, USA
| |
Collapse
|
13
|
Beltran Diaz S, H'ng CH, Qu X, Doube M, Nguyen JT, de Veer M, Panagiotopoulou O, Rosello-Diez A. A New Pipeline to Automatically Segment and Semi-Automatically Measure Bone Length on 3D Models Obtained by Computed Tomography. Front Cell Dev Biol 2021; 9:736574. [PMID: 34513850 PMCID: PMC8427701 DOI: 10.3389/fcell.2021.736574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Accepted: 08/06/2021] [Indexed: 11/13/2022] Open
Abstract
The characterization of developmental phenotypes often relies on the accurate linear measurement of structures that are small and require laborious preparation. This is tedious and prone to errors, especially when repeated for the multiple replicates that are required for statistical analysis, or when multiple distinct structures have to be analyzed. To address this issue, we have developed a pipeline for characterization of long-bone length using X-ray microtomography (XMT) scans. The pipeline involves semi-automated algorithms for automatic thresholding and fast interactive isolation and 3D-model generation of the main limb bones, using either the open-source ImageJ plugin BoneJ or the commercial Mimics Innovation Suite package. The tests showed the appropriate combination of scanning conditions and analysis parameters yields fast and comparable length results, highly correlated with the measurements obtained via ex vivo skeletal preparations. Moreover, since XMT is not destructive, the samples can be used afterward for histology or other applications. Our new pipelines will help developmental biologists and evolutionary researchers to achieve fast, reproducible and non-destructive length measurement of bone samples from multiple animal species.
Collapse
Affiliation(s)
- Santiago Beltran Diaz
- Australian Regenerative Medicine Institute, Monash University, Clayton, VIC, Australia
| | - Chee Ho H'ng
- Australian Regenerative Medicine Institute, Monash University, Clayton, VIC, Australia
| | - Xinli Qu
- Australian Regenerative Medicine Institute, Monash University, Clayton, VIC, Australia
| | - Michael Doube
- Department of Infectious Diseases and Public Health, City University of Hong Kong, Kowloon, Hong Kong, SAR China
| | - John Tan Nguyen
- Australian Regenerative Medicine Institute, Monash University, Clayton, VIC, Australia
| | - Michael de Veer
- Monash Biomedical Imaging, Monash University, Clayton, VIC, Australia
| | - Olga Panagiotopoulou
- Department of Anatomy and Developmental Biology, Monash Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
| | - Alberto Rosello-Diez
- Australian Regenerative Medicine Institute, Monash University, Clayton, VIC, Australia
| |
Collapse
|
14
|
Palci A, LeBlanc ARH, Panagiotopoulou O, Cleuren SGC, Mehari Abraha H, Hutchinson MN, Evans AR, Caldwell MW, Lee MSY. Plicidentine and the repeated origins of snake venom fangs. Proc Biol Sci 2021; 288:20211391. [PMID: 34375553 PMCID: PMC8354744 DOI: 10.1098/rspb.2021.1391] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Accepted: 07/19/2021] [Indexed: 12/26/2022] Open
Abstract
Snake fangs are an iconic exemplar of a complex adaptation, but despite striking developmental and morphological similarities, they probably evolved independently in several lineages of venomous snakes. How snakes could, uniquely among vertebrates, repeatedly evolve their complex venom delivery apparatus is an intriguing question. Here we shed light on the repeated evolution of snake venom fangs using histology, high-resolution computed tomography (microCT) and biomechanical modelling. Our examination of venomous and non-venomous species reveals that most snakes have dentine infoldings at the bases of their teeth, known as plicidentine, and that in venomous species, one of these infoldings was repurposed to form a longitudinal groove for venom delivery. Like plicidentine, venom grooves originate from infoldings of the developing dental epithelium prior to the formation of the tooth hard tissues. Derivation of the venom groove from a large plicidentine fold that develops early in tooth ontogeny reveals how snake venom fangs could originate repeatedly through the co-option of a pre-existing dental feature even without close association to a venom duct. We also show that, contrary to previous assumptions, dentine infoldings do not improve compression or bending resistance of snake teeth during biting; plicidentine may instead have a role in tooth attachment.
Collapse
Affiliation(s)
- Alessandro Palci
- College of Science and Engineering, Flinders University, Adelaide, SA 5042, Australia
- South Australian Museum, North Terrace, Adelaide, SA 5000, Australia
| | - Aaron R. H. LeBlanc
- Department of Biological Sciences, University of Alberta, Edmonton, AB Canada, T6G 2E9
- Faculty of Dentistry, Oral and Craniofacial Sciences, Guy's Campus, King's College London, London WC2R 2LS, UK
| | - Olga Panagiotopoulou
- Department of Anatomy and Developmental Biology, Monash Biomedicine Discovery Institute, Faculty of Medicine Nursing and Health Sciences, Monash University, Melbourne, VIC 3800, Australia
| | | | - Hyab Mehari Abraha
- Department of Anatomy and Developmental Biology, Monash Biomedicine Discovery Institute, Faculty of Medicine Nursing and Health Sciences, Monash University, Melbourne, VIC 3800, Australia
| | - Mark N. Hutchinson
- College of Science and Engineering, Flinders University, Adelaide, SA 5042, Australia
- South Australian Museum, North Terrace, Adelaide, SA 5000, Australia
| | - Alistair R. Evans
- School of Biological Sciences, Monash University, VIC 3800, Australia
- Geosciences, Museums Victoria, Melbourne, VIC 3001, Australia
| | - Michael W. Caldwell
- Department of Biological Sciences, University of Alberta, Edmonton, AB Canada, T6G 2E9
- Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, AB Canada, T6G 2E9
| | - Michael S. Y. Lee
- College of Science and Engineering, Flinders University, Adelaide, SA 5042, Australia
- South Australian Museum, North Terrace, Adelaide, SA 5000, Australia
| |
Collapse
|
15
|
Panagiotopoulou O, Chiesa ST, Tousoulis D, Charakida M. Dyslipidaemias and Cardiovascular Disease: Focus on the Role of PCSK9 Inhibitors. Curr Med Chem 2020; 27:4494-4521. [PMID: 31453780 DOI: 10.2174/0929867326666190827151012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2017] [Revised: 12/23/2018] [Accepted: 01/15/2019] [Indexed: 12/19/2022]
Abstract
Genetic, experimental and clinical studies have consistently confirmed that inhibition of Proprotein Convertase Subtilisin/Kexin type 9 (PCSK9) can result in significant lowering of LDL-C and two fully human PCSK9 monoclonal antibodies have received regulatory approval for use in highrisk patients. Co-administration of PCSK9 with statins has resulted in extremely low LDL-C levels with excellent short-term safety profiles. While results from Phase III clinical trials provided significant evidence about the role of PCSK9 inhibitors in reducing cardiovascular event rates, their impact on mortality remains less clear. PCSK9 inhibitor therapy can be considered for high-risk patients who are likely to experience significant cardiovascular risk reduction.
Collapse
Affiliation(s)
- Olga Panagiotopoulou
- School of Biomedical Engineering and Imaging Sciences, King's College London, 4th Floor, Lambeth Wing St. Thomas' Hospital, London SE1 7EH, United Kingdom
| | - Scott T Chiesa
- UCL Institute of Cardiovascular Sciences, London, United Kingdom
| | | | - Marietta Charakida
- School of Biomedical Engineering and Imaging Sciences, King's College London, 4th Floor, Lambeth Wing St. Thomas' Hospital, London SE1 7EH, United Kingdom
| |
Collapse
|
16
|
Panagiotopoulou O, Iriarte-Diaz J, Mehari Abraha H, Taylor AB, Wilshin S, Dechow PC, Ross CF. Biomechanics of the mandible of Macaca mulatta during the power stroke of mastication: Loading, deformation, and strain regimes and the impact of food type. J Hum Evol 2020; 147:102865. [PMID: 32905895 PMCID: PMC7541691 DOI: 10.1016/j.jhevol.2020.102865] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2020] [Revised: 07/21/2020] [Accepted: 07/21/2020] [Indexed: 12/26/2022]
Abstract
Mandible morphology has yet to yield definitive information on primate diet, probably because of poor understanding of mandibular loading and strain regimes, and overreliance on simple beam models of mandibular mechanics. We used a finite element model of a macaque mandible to test hypotheses about mandibular loading and strain regimes and relate variation in muscle activity during chewing on different foods to variation in strain regimes. The balancing-side corpus is loaded primarily by sagittal shear forces and sagittal bending moments. On the working side, sagittal bending moments, anteroposterior twisting moments, and lateral transverse bending moments all reach similar maxima below the bite point; sagittal shear is the dominant loading regime behind the bite point; and the corpus is twisted such that the mandibular base is inverted. In the symphyseal region, the predominant loading regimes are lateral transverse bending and negative twisting about a mediolateral axis. Compared with grape and dried fruit chewing, nut chewing is associated with larger sagittal and transverse bending moments acting on balancing- and working-side mandibles, larger sagittal shear on the working side, and larger twisting moments about vertical and transverse axes in the symphyseal region. Nut chewing is also associated with higher minimum principal strain magnitudes in the balancing-side posterior ramus; higher sagittal shear strain magnitudes in the working-side buccal alveolar process and the balancing-side oblique line, recessus mandibulae, and endocondylar ridge; and higher transverse shear strains in the symphyseal region, the balancing-side medial prominence, and the balancing-side endocondylar ridge. The largest food-related differences in maximum principal and transverse shear strain magnitudes are in the transverse tori and in the balancing-side medial prominence, extramolar sulcus, oblique line, and endocondylar ridge. Food effects on the strain regime are most salient in areas not traditionally investigated, suggesting that studies seeking dietary effects on mandible morphology might be looking in the wrong places.
Collapse
Affiliation(s)
- Olga Panagiotopoulou
- Department of Anatomy & Developmental Biology, Monash Biomedicine Discovery Institute, Faculty of Medicine Nursing and Health Sciences, Monash University, Clayton, Melbourne, Victoria, 3800, Australia.
| | - Jose Iriarte-Diaz
- Department of Biology, University of the South, Sewanee, TN, 37383, USA
| | - Hyab Mehari Abraha
- Department of Anatomy & Developmental Biology, Monash Biomedicine Discovery Institute, Faculty of Medicine Nursing and Health Sciences, Monash University, Clayton, Melbourne, Victoria, 3800, Australia
| | | | - Simon Wilshin
- Comparative Biomedical Sciences, The Royal Veterinary College, Hawkshead Lane, Herts, AL97TA, UK
| | - Paul C Dechow
- Department of Biomedical Sciences, Texas A&M University College of Dentistry, Dallas, TX, USA
| | - Callum F Ross
- Department of Organismal Biology and Anatomy, University of Chicago, Chicago, IL, 60637, USA.
| |
Collapse
|
17
|
Fung S, Lee J, Yong R, Ranjitkar S, Kaidonis J, Pilbrow V, Panagiotopoulou O, Fiorenza L. A functional analysis of Carabelli trait in Australian aboriginal dentition. Am J Phys Anthropol 2020; 174:375-383. [PMID: 32779189 DOI: 10.1002/ajpa.24120] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Revised: 06/16/2020] [Accepted: 07/08/2020] [Indexed: 12/24/2022]
Abstract
OBJECTIVES Carabelli is a nonmetric dental trait variably expressed as a small pit to a prominent cusp in the maxillary molars of modern humans. Investigations on the occurrence and expression rates of this trait have been conducted extensively, tracing its origin to genetic sources. However, there remains a lack of understanding about its potential role in chewing. In this study, we examine molar macrowear with the aim of reconstructing Carabelli trait occlusal dynamics occurring during chewing. METHODS We have examined 96 deciduous and permanent maxillary molars of children and young adults from Yuendumu, an Australian Aboriginal population that was at an early stage of transition from a nomadic and hunter-gatherer way of life to a more settled existence. We apply a well-established method, called Occlusal Fingerprint Analysis, which is a digital approach for analyzing dental macrowear allowing the reconstruction of jaw movements required to produce wear pattern specific to each tooth. RESULTS Carabelli trait slightly enlarges the surface functional area, especially in those molars where this feature is expressed in its cuspal form and it is closer to the occlusal plane. Moreover, the highly steep contact planes would also indicate that Carabelli wear areas contribute to increasing the shearing abilities of the occluded teeth, which are particularly important when processing fibrous and tough foods. CONCLUSIONS The macrowear analysis suggests that Carabelli trait in the Aboriginal people from Yuendumu slightly enhanced occlusion and probably played some functional role during mastication. Future biomechanical and microwear analyses could provide additional information on the mechanical adaptation of Carabelli trait in modern human dentition.
Collapse
Affiliation(s)
- Sarah Fung
- Monash Biomedicine Discovery Institute, Department of Anatomy and Developmental Biology, Monash University, Melbourne, Victoria, Australia
| | - Jinyoung Lee
- Monash Biomedicine Discovery Institute, Department of Anatomy and Developmental Biology, Monash University, Melbourne, Victoria, Australia
| | - Robin Yong
- Adelaide Dental School, University of Adelaide, Adelaide, South Australia, Australia
| | - Sarbin Ranjitkar
- Adelaide Dental School, University of Adelaide, Adelaide, South Australia, Australia
| | - John Kaidonis
- Adelaide Dental School, University of Adelaide, Adelaide, South Australia, Australia
| | - Varsha Pilbrow
- Australian Institute of Archaeology, La Trobe University, Melbourne, Victoria, Australia
| | - Olga Panagiotopoulou
- Monash Biomedicine Discovery Institute, Department of Anatomy and Developmental Biology, Monash University, Melbourne, Victoria, Australia
| | - Luca Fiorenza
- Monash Biomedicine Discovery Institute, Department of Anatomy and Developmental Biology, Monash University, Melbourne, Victoria, Australia.,Earth Sciences, University of New England, Armidale, New South Wales, Australia
| |
Collapse
|
18
|
Panagiotopoulou O, Syngelaki A, Georgiopoulos G, Simpson J, Akolekar R, Shehata H, Nicolaides K, Charakida M. Metformin use in obese mothers is associated with improved cardiovascular profile in the offspring. Am J Obstet Gynecol 2020; 223:246.e1-246.e10. [PMID: 32017923 DOI: 10.1016/j.ajog.2020.01.054] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2019] [Revised: 01/26/2020] [Accepted: 01/27/2020] [Indexed: 12/13/2022]
Abstract
BACKGROUND Maternal obesity increases the risk for pregnancy complications and adverse neonatal outcome and has been associated with long-lasting adverse effects in the offspring, including increased body fat mass, insulin resistance, and increased risk for premature cardiovascular disease. Lifestyle interventions in pregnancy have produced no or modest effects in the reduction of adverse pregnancy outcomes in obese mothers. The Metformin in Obese Pregnant Women trial was associated with reduced adverse pregnancy outcomes and had no effect on birthweight. However, the long-term implications of metformin on the health of offspring remain unknown. OBJECTIVE The purpose of this study was to assess whether prenatal exposure to metformin can improve the cardiovascular profile and body composition in the offspring of obese mothers. STUDY DESIGN In 151 children from the Metformin in Obese Pregnant Women trial, body composition, peripheral blood pressure, and arterial pulse wave velocity were measured. Central hemodynamics (central blood pressure and augmentation index) were estimated with the use of an oscillometric device. Left ventricular cardiac function and structure were assessed by echocardiography. RESULTS Children were 3.9±1.0 years old, and 77 of them had been exposed to metformin prenatally. There was no significant difference in peripheral blood pressure, arterial stiffness, and body composition apart from gluteal and tricep circumferences, which were lower in the metformin group (P<.05). The metformin group, compared with the placebo group, had lower central hemodynamics (mean adjusted decrease, -0.707 mm Hg for aortic systolic blood pressure, -1.65 mm Hg for aortic pulse pressure, and -2.68% for augmentation index; P<.05 for all) and lower left ventricular diastolic function (adjusted difference in left atrial area, -0.525 cm2, in isovolumic relaxation time, -0.324 msec, and in pulmonary venous systolic wave, 2.97 cm/s; P<.05 for all). There were no significant differences in metabolic profile between the groups. CONCLUSION Children of obese mothers who were exposed prenatally to metformin, compared with those who were exposed to placebo, had lower central hemodynamic and cardiac diastolic indices. These results suggest that the administration of metformin in obese pregnant women potentially may have a beneficial cardiovascular effect for their offspring.
Collapse
Affiliation(s)
- Olga Panagiotopoulou
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, UK
| | - Argyro Syngelaki
- Harris Birthright Research Centre for Fetal Medicine, Fetal Medicine Research Institute, King's College Hospital, London, UK
| | - Georgios Georgiopoulos
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, UK
| | - John Simpson
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, UK
| | - Ranjit Akolekar
- Fetal Medicine Unit, Medway Maritime Hospital, Gillingham, UK
| | - Hassan Shehata
- Department of Maternal Medicine, Epsom and St Helier University Hospitals NHS Trust, Surrey, UK
| | - Kypros Nicolaides
- Harris Birthright Research Centre for Fetal Medicine, Fetal Medicine Research Institute, King's College Hospital, London, UK
| | - Marietta Charakida
- Harris Birthright Research Centre for Fetal Medicine, Fetal Medicine Research Institute, King's College Hospital, London, UK; School of Biomedical Engineering and Imaging Sciences, King's College London, London, UK.
| |
Collapse
|
19
|
To XV, Benetatos J, Soni N, Liu D, Mehari Abraha H, Yan W, Panagiotopoulou O, Nasrallah FA. Ultra-High-Field Diffusion Tensor Imaging Identifies Discrete Patterns of Concussive Injury in the Rodent Brain. J Neurotrauma 2020; 38:967-982. [PMID: 32394788 DOI: 10.1089/neu.2019.6944] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Although concussions can result in persistent neurological post-concussion symptoms, they are typically invisible on routine magnetic resonance imaging (MRI) scans. Our study aimed to investigate the use of ultra-high-field diffusion tensor imaging (UHF-DTI) in discerning severity-dependent microstructural changes in the mouse brain following a concussion. Twenty-three C57BL/6 mice were randomly allocated into three groups: the low concussive (LC, n = 9) injury group, the high concussive (HC, n = 6) injury group, and the sham control (SC, n = 7) group. Mice were perfused on day 2 post-injury, and the brains were scanned on a 16.4T MRI scanner with UHF-DTI and neurite orientation dispersion imaging (NODDI). Finite element analysis (FEA) was performed to determine the pattern and extent of the physical impact on the brain tissue. MRI findings were correlated with histopathological analysis in a subset of mice. In the LC group, increased fractional anisotropy (FA) and decreased orientation dispersion index (ODI) but limited neurite density index (NDI) changes were found in the gray matter, and minimal changes to white matter (WM) were observed. The HC group presented increased mean diffusivity (MD), decreased NDI, and decreased ODI in the WM and gray matter (GM); decreased FA was also found in a small area of the WM. WM changes were associated with WM degeneration and neuroinflammation. FEA showed varying region-dependent degrees of stress, in line with the different imaging findings. This study provides evidence that UHF-DTI combined with NODDI can detect concussions of variable intensities. This has significant implications for the diagnosis of concussion in humans.
Collapse
Affiliation(s)
- Xuan Vinh To
- The Queensland Brain Institute, The University of Queensland, Brisbane, Queensland, Australia
| | - Joseph Benetatos
- The Queensland Brain Institute, The University of Queensland, Brisbane, Queensland, Australia
| | - Neha Soni
- The Queensland Brain Institute, The University of Queensland, Brisbane, Queensland, Australia
| | - Dedao Liu
- Department of Mechanical and Aerospace Engineering, Faculty of Engineering, Department of Anatomy and Developmental Biology, Faculty of Medicine, Nursing and Health Sciences, Monash University, Melbourne, Victoria, Australia
| | - Hyab Mehari Abraha
- Monash Biomedicine Discovery Institute, Department of Anatomy and Developmental Biology, Faculty of Medicine, Nursing and Health Sciences, Monash University, Melbourne, Victoria, Australia
| | - Wenyi Yan
- Department of Mechanical and Aerospace Engineering, Faculty of Engineering, Department of Anatomy and Developmental Biology, Faculty of Medicine, Nursing and Health Sciences, Monash University, Melbourne, Victoria, Australia
| | - Olga Panagiotopoulou
- Monash Biomedicine Discovery Institute, Department of Anatomy and Developmental Biology, Faculty of Medicine, Nursing and Health Sciences, Monash University, Melbourne, Victoria, Australia
| | - Fatima A Nasrallah
- The Queensland Brain Institute, The University of Queensland, Brisbane, Queensland, Australia.,The Center for Advanced Imaging, The University of Queensland, Brisbane, Queensland, Australia
| |
Collapse
|
20
|
Clemente CJ, Dick TJM, Glen CL, Panagiotopoulou O. Biomechanical insights into the role of foot pads during locomotion in camelid species. Sci Rep 2020; 10:3856. [PMID: 32123239 PMCID: PMC7051995 DOI: 10.1038/s41598-020-60795-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Accepted: 02/10/2020] [Indexed: 11/09/2022] Open
Abstract
From the camel’s toes to the horse’s hooves, the diversity in foot morphology among mammals is striking. One distinguishing feature is the presence of fat pads, which may play a role in reducing foot pressures, or may be related to habitat specialization. The camelid family provides a useful paradigm to explore this as within this phylogenetically constrained group we see prominent (camels) and greatly reduced (alpacas) fat pads. We found similar scaling of vertical ground reaction force with body mass, but camels had larger foot contact areas, which increased with velocity, unlike alpacas, meaning camels had relatively lower foot pressures. Further, variation between specific regions under the foot was greater in alpacas than camels. Together, these results provide strong evidence for the role of fat pads in reducing relative peak locomotor foot pressures, suggesting that the fat pad role in habitat specialization remains difficult to disentangle.
Collapse
Affiliation(s)
- Christofer J Clemente
- School of Science and Engineering, University of the Sunshine Coast, Sippy Downs, Australia. .,School of Biomedical Sciences, University of Queensland, St Lucia, Australia.
| | - Taylor J M Dick
- School of Biomedical Sciences, University of Queensland, St Lucia, Australia
| | - Christopher L Glen
- School of Biomedical Sciences, University of Queensland, St Lucia, Australia
| | - Olga Panagiotopoulou
- School of Biomedical Sciences, University of Queensland, St Lucia, Australia. .,Monash Biomedicine Discovery Institute, Department of Anatomy and Developmental Biology, Monash University, Melbourne, Australia.
| |
Collapse
|
21
|
Weisbecker V, Guillerme T, Speck C, Sherratt E, Abraha HM, Sharp AC, Terhune CE, Collins S, Johnston S, Panagiotopoulou O. Individual variation of the masticatory system dominates 3D skull shape in the herbivory-adapted marsupial wombats. Front Zool 2019; 16:41. [PMID: 31695725 PMCID: PMC6824091 DOI: 10.1186/s12983-019-0338-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Accepted: 10/04/2019] [Indexed: 12/19/2022] Open
Abstract
Background Within-species skull shape variation of marsupial mammals is widely considered low and strongly size-dependent (allometric), possibly due to developmental constraints arising from the altricial birth of marsupials. However, species whose skulls are impacted by strong muscular stresses – particularly those produced through mastication of tough food items – may not display such intrinsic patterns very clearly because of the known plastic response of bone to muscle activity of the individual. In such cases, allometry may not dominate within-species shape variation, even if it is a driver of evolutionary shape divergence; ordination of shape in a geometric morphometric context through principal component analysis (PCA) should reveal main variation in areas under masticatory stress (incisor region/zygomatic arches/mandibular ramus); but this main variation should emerge from high individual variability and thus have low eigenvalues. Results We assessed the evidence for high individual variation through 3D geometric morphometric shape analysis of crania and mandibles of three species of grazing-specialized wombats, whose diet of tough grasses puts considerable strain on their masticatory system. As expected, we found little allometry and low Principal Component 1 (PC1) eigenvalues within crania and mandibles of all three species. Also as expected, the main variation was in the muzzle, zygomatic arches, and masticatory muscle attachments of the mandibular ramus. We then implemented a new test to ask if the landmark variation reflected on PC1 was reflected in individuals with opposite PC1 scores and with opposite shapes in Procrustes space. This showed that correspondence between individual and ordinated shape variation was limited, indicating high levels of individual variability in the masticatory apparatus. Discussion Our results are inconsistent with hypotheses that skull shape variation within marsupial species reflects a constraint pattern. Rather, they support suggestions that individual plasticity can be an important determinant of within-species shape variation in marsupials (and possibly other mammals) with high masticatory stresses, making it difficult to understand the degree to which intrinsic constraints act on shape variation at the within-species level. We conclude that studies that link micro- and macroevolutionary patterns of shape variation might benefit from a focus on species with low-impact mastication, such as carnivorous or frugivorous species.
Collapse
Affiliation(s)
- Vera Weisbecker
- 1School of Biological Sciences, The University of Queensland, Brisbane, Australia
| | - Thomas Guillerme
- 1School of Biological Sciences, The University of Queensland, Brisbane, Australia
| | - Cruise Speck
- 1School of Biological Sciences, The University of Queensland, Brisbane, Australia
| | - Emma Sherratt
- 2School of Biological Sciences, The University of Adelaide, Adelaide, Australia
| | - Hyab Mehari Abraha
- 3Monash Biomedicine Discovery Institute, Department of Anatomy & Developmental Biology, Monash University, Melbourne, Australia
| | - Alana C Sharp
- 4Department of Cell & Developmental Biology, University College London, London, UK.,5Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, UK
| | - Claire E Terhune
- 6Department of Anthropology, University of Arkansas, Fayetteville, USA
| | - Simon Collins
- 7School of Agricultural and Food Sciences, The University of Queensland, Brisbane, Australia
| | - Stephen Johnston
- 7School of Agricultural and Food Sciences, The University of Queensland, Brisbane, Australia
| | - Olga Panagiotopoulou
- 3Monash Biomedicine Discovery Institute, Department of Anatomy & Developmental Biology, Monash University, Melbourne, Australia
| |
Collapse
|
22
|
Mehari Abraha H, Iriarte-Diaz J, Ross CF, Taylor AB, Panagiotopoulou O. The Mechanical Effect of the Periodontal Ligament on Bone Strain Regimes in a Validated Finite Element Model of a Macaque Mandible. Front Bioeng Biotechnol 2019; 7:269. [PMID: 31737614 PMCID: PMC6831558 DOI: 10.3389/fbioe.2019.00269] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Accepted: 09/27/2019] [Indexed: 11/13/2022] Open
Abstract
The primary anatomical function of the periodontal ligament (PDL) is to attach teeth to their sockets. However, theoretical and constitutive mechanical models have proposed that during mastication the PDL redistributes local occlusal loads and reduces the jaw's resistance to torsional deformations. These hypotheses imply that accurately modeling the PDL's material properties and geometry in finite element analysis (FEA) is a prerequisite to obtaining precise strain and deformation data. Yet, many finite element studies of the human and non-human primate masticatory apparatus exclude the PDL or model it with simplicity, in part due to limitations in μCT/CT scan resolution and material property assignment. Previous studies testing the sensitivity of finite element models (FEMs) to the PDL have yielded contradictory results, however a major limitation of these studies is that FEMs were not validated against in vivo bone strain data. Hence, this study uses a validated and subject specific FEM to assess the effect of the PDL on strain and deformation regimes in the lower jaw of a rhesus macaque (Macaca mulatta) during simulated unilateral post-canine chewing. Our findings demonstrate that the presence of the PDL does influence local and global surface strain magnitudes (principal and shear) in the jaw. However, the PDL's effect is limited (diff. ~200-300 με) in areas away from the alveoli. Our results also show that varying the PDL's Young's Modulus within the range of published values (0.07-1750 MPa) has very little effect on global surface strains. These findings suggest that the mechanical importance of the PDL in FEMs of the mandible during chewing is dependent on the scope of the hypotheses being tested. If researchers are comparing strain gradients across species/taxa, the PDL may be excluded with minimal effect on results, but, if researchers are concerned with absolute strain values, sensitivity analysis is required.
Collapse
Affiliation(s)
- Hyab Mehari Abraha
- Moving Morphology and Functional Mechanics Laboratory, Department of Anatomy and Developmental Biology, Monash Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
| | - Jose Iriarte-Diaz
- Department of Biology, The University of the South, Sewanee, TN, United States
| | - Callum F. Ross
- Department of Organismal Biology and Anatomy, University of Chicago, Chicago, IL, United States
| | - Andrea B. Taylor
- Department of Basic Science, Touro University, Vallejo, CA, United States
| | - Olga Panagiotopoulou
- Moving Morphology and Functional Mechanics Laboratory, Department of Anatomy and Developmental Biology, Monash Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
| |
Collapse
|
23
|
Affiliation(s)
- Ageliki A. Karatza
- Department of Pediatrics, University of Patras Medical School, Patras, Greece
- * Address for Correspondence: Department of Pediatrics, University of Patras Medical School, Patras, Greece Phone: +30-2610-999821 E-mail:
| | | | - Despoina Gkentzi
- Department of Pediatrics, University of Patras Medical School, Patras, Greece
| | - Gabriel Dimitriou
- Department of Pediatrics, University of Patras Medical School, Patras, Greece
| |
Collapse
|
24
|
Panagiotopoulou O, Pataky TC, Hutchinson JR. Foot pressure distribution in White Rhinoceroses ( Ceratotherium simum) during walking. PeerJ 2019; 7:e6881. [PMID: 31143533 PMCID: PMC6525597 DOI: 10.7717/peerj.6881] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Accepted: 04/01/2019] [Indexed: 11/20/2022] Open
Abstract
White rhinoceroses (Ceratotherium simum) are odd-toed ungulates that belong to the group Perissodactyla. Being second only to elephants in terms of large body mass amongst extant tetrapods, rhinoceroses make fascinating subjects for the study of how large land animals support and move themselves. Rhinoceroses often are kept in captivity for protection from ivory poachers and for educational/touristic purposes, yet a detrimental side effect of captivity can be foot disease (i.e., enthesopathies and osteoarthritis around the phalanges). Foot diseases in large mammals are multifactorial, but locomotor biomechanics (e.g., pressures routinely experienced by the feet) surely can be a contributing factor. However, due to a lack of in vivo experimental data on rhinoceros foot pressures, our knowledge of locomotor performance and its links to foot disease is limited. The overall aim of this study was to characterize peak pressures and center of pressure trajectories in white rhinoceroses during walking. We asked two major questions. First, are peak locomotor pressures the lowest around the fat pad and its lobes (as in the case of elephants)? Second, are peak locomotor pressures concentrated around the areas with the highest reported incidence of pathologies? Our results show a reduction of pressures around the fat pad and its lobes, which is potentially due to the material properties of the fat pad or a tendency to avoid or limit "heel" contact at impact. We also found an even and gradual concentration of foot pressures across all digits, which may be a by-product of the more horizontal foot roll-off during the stance phase. While our exploratory, descriptive sample precluded hypothesis testing, our study provides important new data on rhinoceros locomotion for future studies to build on, and thus impetus for improved implementation in the care of captive/managed rhinoceroses.
Collapse
Affiliation(s)
- Olga Panagiotopoulou
- Monash Biomedicine Discovery Institute, Department of Anatomy and Developmental Biology, Moving Morphology & Functional Mechanics Laboratory, Monash University, Clayton, VIC, Australia
| | - Todd C Pataky
- Department of Human Health Sciences, Kyoto University, Kyoto, Japan
| | - John R Hutchinson
- Department of Comparative Biomedical Sciences, Structure and Motion Laboratory, Royal Veterinary College, Hatfield, UK
| |
Collapse
|
25
|
Jannel A, Nair JP, Panagiotopoulou O, Romilio A, Salisbury SW. “Keep your feet on the ground”: Simulated range of motion and hind foot posture of the Middle Jurassic sauropod
Rhoetosaurus brownei
and its implications for sauropod biology. J Morphol 2019; 280:849-878. [DOI: 10.1002/jmor.20989] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Revised: 03/06/2019] [Accepted: 03/21/2019] [Indexed: 11/11/2022]
Affiliation(s)
- Andréas Jannel
- School of Biological SciencesThe University of Queensland Brisbane Queensland Australia
| | - Jay P. Nair
- School of Biological SciencesThe University of Queensland Brisbane Queensland Australia
| | - Olga Panagiotopoulou
- Department of Anatomy and Developmental BiologyMonash Biomedicine Discovery Institute, Monash University Clayton Victoria Australia
| | - Anthony Romilio
- School of Biological SciencesThe University of Queensland Brisbane Queensland Australia
| | - Steven W. Salisbury
- School of Biological SciencesThe University of Queensland Brisbane Queensland Australia
| |
Collapse
|
26
|
Feng T, Paterson B, Panagiotopoulou O, Green K, Mardon K, Johnston S. The functional anatomy of external genitalia in the black tiger prawn (Penaeus monodon) studied by micro-computed tomography and scanning electron microscopy. J Morphol 2018; 279:1346-1354. [PMID: 30117611 DOI: 10.1002/jmor.20875] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Revised: 06/22/2018] [Accepted: 06/26/2018] [Indexed: 11/06/2022]
Abstract
Although artificial insemination has been used for decades in Penaeus monodon aquaculture, the interaction of male and female external genitalia during spermatophore transfer has not been fully documented. As a result, studying the functional anatomy of this process may help to better refine the insemination technique. The sexual act in penaeoid prawns is virtually impossible to observe directly; as a result, this study aimed to describe the functional anatomy and interaction of external genitalia, such as the petasma, appendices masculinae and genital papillae of the male, with that of the thelycum and genital lobes of the female, using a combination of micro-computed tomography and scanning electron microscopy. We hypothesise that the spermatophores are ejaculated into the ventromedial groove of the petasma and squeezed by abdominal flexure into the spermathecae of female's thelycum. During this process, the 'spike-like' setae observed on the petasma and appendices masculinae are speculated to control the transferring direction of the spermatophores. The approach of three dimensional remodelling and animation reported in this study may prove useful in the examination of further hypotheses related to the functional anatomy of external genitalia and/or appendages for other crustacean species.
Collapse
Affiliation(s)
- Tianyi Feng
- School of Agriculture and Food Sciences, University of Queensland, Gatton, Queensland, Australia
| | - Brian Paterson
- Queensland Department of Agriculture and Fisheries, Bribie Island Research Centre, Woorim, Queensland, Australia
| | - Olga Panagiotopoulou
- Monash Biomedicine Discovery Institute, School of Biomedical Sciences, Monash University, Clayton, Victoria, Australia
| | - Kathryn Green
- Centre for Microscopy & Microanalysis, University of Queensland, St Lucia, Queensland, Australia
| | - Karine Mardon
- Centre for Advanced Imaging, University of Queensland, St Lucia, Queensland, Australia
| | - Stephen Johnston
- School of Agriculture and Food Sciences, University of Queensland, Gatton, Queensland, Australia
| |
Collapse
|
27
|
Iriarte-Díaz J, Panagiotopoulou O. Editorial: Determinants of mammalian feeding system design. ZOOLOGY 2017; 124:1-2. [PMID: 29224670 DOI: 10.1016/j.zool.2017.10.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
- José Iriarte-Díaz
- Department of Oral Biology, University of Illinois at Chicago, 801 S. Paulina St., Chicago, IL 60612, USA.
| | - Olga Panagiotopoulou
- Moving Morphology and Functional Mechanics Laboratory, School of Biomedical Sciences, The University of Queensland, St Lucia, Brisbane, QLD 4072, Australia; Department of Anatomy and Developmental Biology, School of Biomedical Sciences, Monash University, Clayton, Melbourne, VIC 3800, Australia.
| |
Collapse
|
28
|
Panagiotopoulou O, Iriarte-Diaz J, Wilshin S, Dechow PC, Taylor AB, Mehari Abraha H, Aljunid SF, Ross CF. In vivo bone strain and finite element modeling of a rhesus macaque mandible during mastication. ZOOLOGY 2017; 124:13-29. [PMID: 29037463 DOI: 10.1016/j.zool.2017.08.010] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2016] [Revised: 08/25/2017] [Accepted: 08/25/2017] [Indexed: 12/29/2022]
Abstract
Finite element analysis (FEA) is a commonly used tool in musculoskeletal biomechanics and vertebrate paleontology. The accuracy and precision of finite element models (FEMs) are reliant on accurate data on bone geometry, muscle forces, boundary conditions and tissue material properties. Simplified modeling assumptions, due to lack of in vivo experimental data on material properties and muscle activation patterns, may introduce analytical errors in analyses where quantitative accuracy is critical for obtaining rigorous results. A subject-specific FEM of a rhesus macaque mandible was constructed, loaded and validated using in vivo data from the same animal. In developing the model, we assessed the impact on model behavior of variation in (i) material properties of the mandibular trabecular bone tissue and teeth; (ii) constraints at the temporomandibular joint and bite point; and (iii) the timing of the muscle activity used to estimate the external forces acting on the model. The best match between the FEA simulation and the in vivo experimental data resulted from modeling the trabecular tissue with an isotropic and homogeneous Young's modulus and Poisson's value of 10GPa and 0.3, respectively; constraining translations along X,Y, Z axes in the chewing (left) side temporomandibular joint, the premolars and the m1; constraining the balancing (right) side temporomandibular joint in the anterior-posterior and superior-inferior axes, and using the muscle force estimated at time of maximum strain magnitude in the lower lateral gauge. The relative strain magnitudes in this model were similar to those recorded in vivo for all strain locations. More detailed analyses of mandibular strain patterns during the power stroke at different times in the chewing cycle are needed.
Collapse
Affiliation(s)
- Olga Panagiotopoulou
- Moving Morphology & Functional Mechanics Laboratory, School of Biomedical Sciences, The University of Queensland, St Lucia, Brisbane, QLD 4072, Australia; Department of Anatomy and Developmental Biology, School of Biomedical Sciences, Faculty of Medicine, Nursing and Health Sciences, Monash University, Clayton, Melbourne, Victoria 3800, Australia
| | - José Iriarte-Diaz
- Department of Oral Biology, University of Illinois, 801 S. Paulina St., Chicago, IL 60612, USA
| | - Simon Wilshin
- Department of Biomedical Sciences, The Royal Veterinary College, Hawkshead Lane, North Mymms, Hatfield, Hertfordshire AL9 7TA, United Kingdom
| | - Paul C Dechow
- Department of Biomedical Sciences, College of Dentistry, Texas A&M University, 3302 Gaston Ave., Dallas, TX 75246, USA
| | - Andrea B Taylor
- Department of Basic Science, Touro University, 1310 Club Drive, Mare Island, Vellejo, CA 94592, USA
| | - Hyab Mehari Abraha
- Moving Morphology & Functional Mechanics Laboratory, School of Biomedical Sciences, The University of Queensland, St Lucia, Brisbane, QLD 4072, Australia
| | - Sharifah F Aljunid
- Materialise Unit 5-01, Menara OBYU, No. 4, Jalan PJU 8/8A, Damansara Perdana, 47820 Petaling Jaya, Selangor, Malaysia
| | - Callum F Ross
- Department of Organismal Biology and Anatomy, University of Chicago, 1027 E. 57th St., Chicago, IL 60637, USA.
| |
Collapse
|
29
|
Fouzas S, Panagiotopoulou O, Sinopidis X, Papadopoulou C, Dimitriou G, Karatza AA. Surgical anomalies in twins: The role of assisted reproductive technology and chorionicity: RE: "Congenital malformations associated with assisted reproductive technology: A California statewide analysis" by Kelley-Quon LI et al. J Pediatr Surg 2013; 48; 1218-1224. J Pediatr Surg 2017; 52:1379-1380. [PMID: 28456424 DOI: 10.1016/j.jpedsurg.2017.03.065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Accepted: 03/22/2017] [Indexed: 02/05/2023]
Affiliation(s)
- Sotirios Fouzas
- Department of Paediatrics, NICU, University of Patras Medical School, Patras, Greece.
| | - Olga Panagiotopoulou
- Department of Paediatrics, NICU, University of Patras Medical School, Patras, Greece
| | - Xenophon Sinopidis
- Department of Paediatric Surgery, University of Patras Medical School, Patras, Greece
| | | | - Gabriel Dimitriou
- Department of Paediatrics, NICU, University of Patras Medical School, Patras, Greece
| | - Ageliki A Karatza
- Department of Paediatrics, NICU, University of Patras Medical School, Patras, Greece
| |
Collapse
|
30
|
Dechow PC, Panagiotopoulou O, Gharpure P. Biomechanical implications of cortical elastic properties of the macaque mandible. ZOOLOGY 2017; 124:3-12. [PMID: 28811166 DOI: 10.1016/j.zool.2017.06.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Revised: 06/15/2017] [Accepted: 06/15/2017] [Indexed: 11/24/2022]
Abstract
Knowledge of the variation in the elastic properties of mandibular cortical bone is essential for modeling bone function. Our aim was to characterize the elastic properties of rhesus macaque mandibular cortical bone and compare these to the elastic properties from mandibles of dentate humans and baboons. Thirty cylindrical samples were harvested from each of six adult female rhesus monkey mandibles. Assuming orthotropy, axes of maximum stiffness in the plane of the cortical plate were derived from ultrasound velocity measurements. Further velocity measurements with longitudinal and transverse ultrasonic transducers along with measurements of bone density were used to compute three-dimensional cortical elastic properties using equations based on Hooke's law. Results showed regional variations in the elastic properties of macaque mandibular cortical bone that have both similarities and differences with that of humans and baboons. So far, the biological and structural basis of these differences is poorly understood.
Collapse
Affiliation(s)
- Paul C Dechow
- Department of Biomedical Sciences, College of Dentistry, Texas A&M University, 3302 Gaston Avenue, Dallas, TX 75204, USA.
| | - Olga Panagiotopoulou
- Moving Morphology and Functional Mechanics Laboratory, School of Biomedical Sciences, University of Queensland, St. Lucia 4072, Brisbane, QLD, Australia
| | - Poorva Gharpure
- Department of Prosthodontics, Rutgers School of Dental Medicine, 110 Bergen Street, Newark, NJ 07103, USA
| |
Collapse
|
31
|
Panagiotopoulou O, Pataky TC, Day M, Hensman MC, Hensman S, Hutchinson JR, Clemente CJ. Foot pressure distributions during walking in African elephants ( Loxodonta africana). R Soc Open Sci 2016; 3:160203. [PMID: 27853539 PMCID: PMC5098964 DOI: 10.1098/rsos.160203] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Accepted: 08/28/2016] [Indexed: 06/06/2023]
Abstract
Elephants, the largest living land mammals, have evolved a specialized foot morphology to help reduce locomotor pressures while supporting their large body mass. Peak pressures that could cause tissue damage are mitigated passively by the anatomy of elephants' feet, yet this mechanism does not seem to work well for some captive animals. This study tests how foot pressures vary among African and Asian elephants from habitats where natural substrates predominate but where foot care protocols differ. Variations in pressure patterns might be related to differences in husbandry, including but not limited to trimming and the substrates that elephants typically stand and move on. Both species' samples exhibited the highest concentration of peak pressures on the lateral digits of their feet (which tend to develop more disease in elephants) and lower pressures around the heel. The trajectories of the foot's centre of pressure were also similar, confirming that when walking at similar speeds, both species load their feet laterally at impact and then shift their weight medially throughout the step until toe-off. Overall, we found evidence of variations in foot pressure patterns that might be attributable to husbandry and other causes, deserving further examination using broader, more comparable samples.
Collapse
Affiliation(s)
- Olga Panagiotopoulou
- Moving Morphology and Functional Mechanics Laboratory, School of Biomedical Sciences, The University of Queensland, Brisbane, Australia
| | - Todd C. Pataky
- Institute for Fiber Engineering, Department of Bioengineering, Shinshu University, Ueda, Japan
| | - Madeleine Day
- Moving Morphology and Functional Mechanics Laboratory, School of Biomedical Sciences, The University of Queensland, Brisbane, Australia
| | - Michael C. Hensman
- Adventures with Elephants, PO Box 1500, Bela Bela 0480, Limpopo, South Africa
| | - Sean Hensman
- Adventures with Elephants, PO Box 1500, Bela Bela 0480, Limpopo, South Africa
| | - John R. Hutchinson
- Moving Morphology and Functional Mechanics Laboratory, School of Biomedical Sciences, The University of Queensland, Brisbane, Australia
- Structure and Motion Laboratory, Department of Comparative Biomedical Sciences, The Royal Veterinary College, Hatfield, UK
| | | |
Collapse
|
32
|
Panagiotopoulou O, Fouzas S, Sinopidis X, Mantagos SP, Dimitriou G, Karatza AA. Congenital heart disease in twins: The contribution of type of conception and chorionicity. Int J Cardiol 2016; 218:144-149. [PMID: 27232926 DOI: 10.1016/j.ijcard.2016.05.029] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Revised: 05/07/2016] [Accepted: 05/12/2016] [Indexed: 02/08/2023]
Abstract
BACKGROUND Increased incidence of congenital heart disease (CHD) has been reported in the offspring of monochorionic twin gestations. Assisted reproductive technology (ART), which is related to increased rates of twinning, has also been associated with higher risk of birth defects. We studied the incidence of CHD in a cohort of twins to clarify the contribution of type of conception and chorionicity. METHODS Data concerning 874 live-born twins of which at least one was admitted in our Neonatal Unit during 1995-2012 were analysed. Forty-five % (N=197) of the gestations resulted from ART (in vitro fertilisation or intracytoplasmic sperm insertion). RESULTS In the ART group 32/389 (8.2%) had CHD compared to 21/485 (4.3%) infants conceived naturally (OR 1.90, 95%CI 1.08-3.34, p=0.024). Spontaneous-conception gestations had higher incidence of monochorionic placentation (47/245 versus 4/197, p<0.001), and included younger mothers (29.1±5.2 versus 33.9±5.5years, p<0.001) who had higher parity (median 2 [range 1-7] versus 1 Pinborg (2005), Blondel and Kaminski (2002), Knopman et al. (2014), Kyvik and Derom (2006) ; p<0.001). Multivariable logistic regression analysis showed that ART (OR 2.60, 95% CI 1.24-5.45) and monochorionicity (OR 3.49, 95% CI 1.57-7.77) were significant determinants of CHD, independently of maternal age, parity, and the gender of the offspring. CONCLUSIONS We confirmed that monochorionic twins have increased risk of CHD and we documented a higher incidence of CHD in ART twins independently of chorionicity. We suggest improvement of echocardiographic skills of health care professionals involved in prenatal screening and foetal cardiology referral of ART dichorionic twins with suspicious findings at screening, in addition to all monochorionic gestations.
Collapse
Affiliation(s)
- Olga Panagiotopoulou
- Department of Paediatrics, Neonatal Intensive Care Unit, University of Patras Medical School, Patras, Greece
| | - Sotirios Fouzas
- Department of Paediatrics, Neonatal Intensive Care Unit, University of Patras Medical School, Patras, Greece
| | - Xenophon Sinopidis
- Department of Paediatrics, Neonatal Intensive Care Unit, University of Patras Medical School, Patras, Greece
| | - Stefanos P Mantagos
- Department of Paediatrics, Neonatal Intensive Care Unit, University of Patras Medical School, Patras, Greece
| | - Gabriel Dimitriou
- Department of Paediatrics, Neonatal Intensive Care Unit, University of Patras Medical School, Patras, Greece
| | - Ageliki A Karatza
- Department of Paediatrics, Neonatal Intensive Care Unit, University of Patras Medical School, Patras, Greece.
| |
Collapse
|
33
|
Panagiotopoulou O, Rankin JW, Gatesy SM, Hutchinson JR. A preliminary case study of the effect of shoe-wearing on the biomechanics of a horse's foot. PeerJ 2016; 4:e2164. [PMID: 27478694 PMCID: PMC4950542 DOI: 10.7717/peerj.2164] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Accepted: 06/01/2016] [Indexed: 11/20/2022] Open
Abstract
Horse racing is a multi-billion-dollar industry that has raised welfare concerns due to injured and euthanized animals. Whilst the cause of musculoskeletal injuries that lead to horse morbidity and mortality is multifactorial, pre-existing pathologies, increased speeds and substrate of the racecourse are likely contributors to foot disease. Horse hooves have the ability to naturally deform during locomotion and dissipate locomotor stresses, yet farriery approaches are utilised to increase performance and protect hooves from wear. Previous studies have assessed the effect of different shoe designs on locomotor performance; however, no biomechanical study has hitherto measured the effect of horseshoes on the stresses of the foot skeleton in vivo. This preliminary study introduces a novel methodology combining three-dimensional data from biplanar radiography with inverse dynamics methods and finite element analysis (FEA) to evaluate the effect of a stainless steel shoe on the function of a Thoroughbred horse's forefoot during walking. Our preliminary results suggest that the stainless steel shoe shifts craniocaudal, mediolateral and vertical GRFs at mid-stance. We document a similar pattern of flexion-extension in the PIP (pastern) and DIP (coffin) joints between the unshod and shod conditions, with slight variation in rotation angles throughout the stance phase. For both conditions, the PIP and DIP joints begin in a flexed posture and extend over the entire stance phase. At mid-stance, small differences in joint angle are observed in the PIP joint, with the shod condition being more extended than the unshod horse, whereas the DIP joint is extended more in the unshod than the shod condition. We also document that the DIP joint extends more than the PIP after mid-stance and until the end of the stance in both conditions. Our FEA analysis, conducted solely on the bones, shows increased von Mises and Maximum principal stresses on the forefoot phalanges in the shod condition at mid-stance, consistent with the tentative conclusion that a steel shoe might increase mechanical loading. However, because of our limited sample size none of these apparent differences have been tested for statistical significance. Our preliminary study illustrates how the shoe may influence the dynamics and mechanics of a Thoroughbred horse's forefoot during slow walking, but more research is needed to quantify the effect of the shoe on the equine forefoot during the whole stance phase, at faster speeds/gaits and with more individuals as well as with a similar focus on the hind feet. We anticipate that our preliminary analysis using advanced methodological approaches will pave the way for new directions in research on the form/function relationship of the equine foot, with the ultimate goal to minimise foot injuries and improve animal health and welfare.
Collapse
Affiliation(s)
- Olga Panagiotopoulou
- Structure & Motion Laboratory, Department of Comparative Biomedical Sciences, The Royal Veterinary College, Hatfield, Hertfordshire, United Kingdom
- Moving Morphology & Functional Mechanics Laboratory, School of Biomedical Sciences, Faculty of Medicine and Biomedical Sciences, The University of Queensland, Brisbane, Australia
| | - Jeffery W. Rankin
- Structure & Motion Laboratory, Department of Comparative Biomedical Sciences, The Royal Veterinary College, Hatfield, Hertfordshire, United Kingdom
| | - Stephen M. Gatesy
- Department of Ecology and Evolutionary Biology, Brown University, Providence, RI, USA
| | - John R. Hutchinson
- Structure & Motion Laboratory, Department of Comparative Biomedical Sciences, The Royal Veterinary College, Hatfield, Hertfordshire, United Kingdom
- Moving Morphology & Functional Mechanics Laboratory, School of Biomedical Sciences, Faculty of Medicine and Biomedical Sciences, The University of Queensland, Brisbane, Australia
| |
Collapse
|
34
|
Hadjilouka A, Molfeta C, Panagiotopoulou O, Paramithiotis S, Mataragas M, Drosinos EH. Expression of Listeria monocytogenes key virulence genes during growth in liquid medium, on rocket and melon at 4, 10 and 30 °C. Food Microbiol 2016; 55:7-15. [DOI: 10.1016/j.fm.2015.11.008] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Revised: 10/19/2015] [Accepted: 11/17/2015] [Indexed: 10/22/2022]
|
35
|
Panagiotopoulou O, Spyridis P, Mehari Abraha H, Carrier DR, Pataky TC. Architecture of the sperm whale forehead facilitates ramming combat. PeerJ 2016; 4:e1895. [PMID: 27069822 PMCID: PMC4824896 DOI: 10.7717/peerj.1895] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Accepted: 03/14/2016] [Indexed: 11/20/2022] Open
Abstract
Herman Melville’s novel Moby Dick was inspired by historical instances in which large sperm whales (Physeter macrocephalus L.) sank 19th century whaling ships by ramming them with their foreheads. The immense forehead of sperm whales is possibly the largest, and one of the strangest, anatomical structures in the animal kingdom. It contains two large oil-filled compartments, known as the “spermaceti organ” and “junk,” that constitute up to one-quarter of body mass and extend one-third of the total length of the whale. Recognized as playing an important role in echolocation, previous studies have also attributed the complex structural configuration of the spermaceti organ and junk to acoustic sexual selection, acoustic prey debilitation, buoyancy control, and aggressive ramming. Of these additional suggested functions, ramming remains the most controversial, and the potential mechanical roles of the structural components of the spermaceti organ and junk in ramming remain untested. Here we explore the aggressive ramming hypothesis using a novel combination of structural engineering principles and probabilistic simulation to determine if the unique structure of the junk significantly reduces stress in the skull during quasi-static impact. Our analyses indicate that the connective tissue partitions in the junk reduce von Mises stresses across the skull and that the load-redistribution functionality of the former is insensitive to moderate variation in tissue material parameters, the thickness of the partitions, and variations in the location and angle of the applied load. Absence of the connective tissue partitions increases skull stresses, particularly in the rostral aspect of the upper jaw, further hinting of the important role the architecture of the junk may play in ramming events. Our study also found that impact loads on the spermaceti organ generate lower skull stresses than an impact on the junk. Nevertheless, whilst an impact on the spermaceti organ would reduce skull stresses, it would also cause high compressive stresses on the anterior aspect of the organ and the connective tissue case, possibly making these structures more prone to failure. This outcome, coupled with the facts that the spermaceti organ houses sensitive and essential sonar producing structures and the rostral portion of junk, rather than the spermaceti organ, is frequently a site of significant scarring in mature males suggest that whales avoid impact with the spermaceti organ. Although the unique structure of the junk certainly serves multiple functions, our results are consistent with the hypothesis that the structure also evolved to function as a massive battering ram during male-male competition.
Collapse
Affiliation(s)
- Olga Panagiotopoulou
- Faculty of Medicine and Biomedical Sciences, Moving Morphology & Functional Mechanics Laboratory, School of Biomedical Sciences, The University of Queensland , Brisbane , Australia
| | - Panagiotis Spyridis
- Polytropos Ltd, London, United Kingdom; Department of Civil Engineering and Natural Hazards, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Hyab Mehari Abraha
- Faculty of Medicine and Biomedical Sciences, Moving Morphology & Functional Mechanics Laboratory, School of Biomedical Sciences, The University of Queensland , Brisbane , Australia
| | - David R Carrier
- Department of Biology, University of Utah , Salt Lake City , Utah, United States of America
| | - Todd C Pataky
- Institute for Fiber Engineering, Department of Bioengineering, Shinshu University , Ueda, Nagano , Japan
| |
Collapse
|
36
|
Panagiotopoulou O, Curtis N, O’Higgins P, Cobb S. Retraction notice to erratum to “Modelling subcortical bone in finite element analyses: A validation and sensitivity study in the macaque mandible” [J. Biomech. 43 (2010) 2867]. J Biomech 2015; 48:1234. [DOI: 10.1016/j.jbiomech.2015.02.046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
|
37
|
Affiliation(s)
- Olga Panagiotopoulou
- Department of Comparative Biomedical SciencesThe Royal Veterinary CollegeUnited Kingdom
- School of Biomedical Sciences The University of QueenslandAustralia
| | - Jeffery Rankin
- Department of Comparative Biomedical SciencesThe Royal Veterinary CollegeUnited Kingdom
| | - Stephen Gatesy
- Department of Ecology and Evolutionary Biology Brown UniversityUnited States
| | - John Hutchinson
- Department of Comparative Biomedical SciencesThe Royal Veterinary CollegeUnited Kingdom
| |
Collapse
|
38
|
Panagiotopoulou O, Wilshin SD, Rayfield EJ, Shefelbine SJ, Hutchinson JR. What makes an accurate and reliable subject-specific finite element model? A case study of an elephant femur. J R Soc Interface 2014; 11:rsif.2014.0854. [DOI: 10.1098/rsif.2014.0854] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
|
39
|
Panagiotopoulou O, Wilshin SD, Rayfield EJ, Shefelbine SJ, Hutchinson JR. What makes an accurate and reliable subject-specific finite element model? A case study of an elephant femur. J R Soc Interface 2014; 11:20140700. [PMID: 25030388 PMCID: PMC4233712 DOI: 10.1098/rsif.2014.0700] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
|
40
|
Samuel CN, Panagiotopoulou O. Retracted: Corrigendum. J Anat 2014; 224:252-254. [PMID: 28349544 DOI: 10.1111/joa.12146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
|
41
|
Warner SE, Pickering P, Panagiotopoulou O, Pfau T, Ren L, Hutchinson JR. Size-related changes in foot impact mechanics in hoofed mammals. PLoS One 2013; 8:e54784. [PMID: 23382967 PMCID: PMC3559824 DOI: 10.1371/journal.pone.0054784] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2012] [Accepted: 12/17/2012] [Indexed: 11/18/2022] Open
Abstract
Foot-ground impact is mechanically challenging for all animals, but how do large animals mitigate increased mass during foot impact? We hypothesized that impact force amplitude scales according to isometry in animals of increasing size through allometric scaling of related impact parameters. To test this, we measured limb kinetics and kinematics in 11 species of hoofed mammals ranging from 18-3157 kg body mass. We found impact force amplitude to be maintained proportional to size in hoofed mammals, but that other features of foot impact exhibit differential scaling patterns depending on the limb; forelimb parameters typically exhibit higher intercepts with lower scaling exponents than hind limb parameters. Our explorations of the size-related consequences of foot impact advance understanding of how body size influences limb morphology and function, foot design and locomotor behaviour.
Collapse
Affiliation(s)
- Sharon Elaine Warner
- Structure and Motion Laboratory, Comparative Biomedical Sciences, The Royal Veterinary College, Hatfield, Hertfordshire, United Kingdom.
| | | | | | | | | | | |
Collapse
|
42
|
Panagiotopoulou O, Pataky TC, Hill Z, Hutchinson JR. Statistical parametric mapping of the regional distribution and ontogenetic scaling of foot pressures during walking in Asian elephants (Elephas maximus). ACTA ACUST UNITED AC 2012; 215:1584-93. [PMID: 22496296 DOI: 10.1242/jeb.065862] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Foot pressure distributions during locomotion have causal links with the anatomical and structural configurations of the foot tissues and the mechanics of locomotion. Elephant feet have five toes bound in a flexible pad of fibrous tissue (digital cushion). Does this specialized foot design control peak foot pressures in such giant animals? And how does body size, such as during ontogenetic growth, influence foot pressures? We addressed these questions by studying foot pressure distributions in elephant feet and their correlation with body mass and centre of pressure trajectories, using statistical parametric mapping (SPM), a neuro-imaging technology. Our results show a positive correlation between body mass and peak pressures, with the highest pressures dominated by the distal ends of the lateral toes (digits 3, 4 and 5). We also demonstrate that pressure reduction in the elephant digital cushion is a complex interaction of its viscoelastic tissue structure and its centre of pressure trajectories, because there is a tendency to avoid rear 'heel' contact as an elephant grows. Using SPM, we present a complete map of pressure distributions in elephant feet during ontogeny by performing statistical analysis at the pixel level across the entire plantar/palmar surface. We hope that our study will build confidence in the potential clinical and scaling applications of mammalian foot pressures, given our findings in support of a link between regional peak pressures and pathogenesis in elephant feet.
Collapse
Affiliation(s)
- Olga Panagiotopoulou
- Structure and Motion Laboratory, Department of Veterinary Basic Sciences, The Royal Veterinary College, University of London, Hatfield, AL9 7TA, UK.
| | | | | | | |
Collapse
|
43
|
Panagiotopoulou O, Wilshin SD, Rayfield EJ, Shefelbine SJ, Hutchinson JR. What makes an accurate and reliable subject-specific finite element model? A case study of an elephant femur. J R Soc Interface 2012; 9:351-61. [PMID: 21752810 PMCID: PMC3243395 DOI: 10.1098/rsif.2011.0323] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2011] [Accepted: 06/22/2011] [Indexed: 11/12/2022] Open
Abstract
Finite element modelling is well entrenched in comparative vertebrate biomechanics as a tool to assess the mechanical design of skeletal structures and to better comprehend the complex interaction of their form-function relationships. But what makes a reliable subject-specific finite element model? To approach this question, we here present a set of convergence and sensitivity analyses and a validation study as an example, for finite element analysis (FEA) in general, of ways to ensure a reliable model. We detail how choices of element size, type and material properties in FEA influence the results of simulations. We also present an empirical model for estimating heterogeneous material properties throughout an elephant femur (but of broad applicability to FEA). We then use an ex vivo experimental validation test of a cadaveric femur to check our FEA results and find that the heterogeneous model matches the experimental results extremely well, and far better than the homogeneous model. We emphasize how considering heterogeneous material properties in FEA may be critical, so this should become standard practice in comparative FEA studies along with convergence analyses, consideration of element size, type and experimental validation. These steps may be required to obtain accurate models and derive reliable conclusions from them.
Collapse
Affiliation(s)
- O Panagiotopoulou
- Structure and Motion Laboratory, Department of Veterinary Basic Sciences, The Royal Veterinary College, University of London, London, UK.
| | | | | | | | | |
Collapse
|
44
|
Panagiotopoulou O, Cobb SN. The mechanical significance of morphological variation in the macaque mandibular symphysis during mastication. Am J Phys Anthropol 2011; 146:253-61. [PMID: 21826640 DOI: 10.1002/ajpa.21573] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2010] [Accepted: 05/11/2011] [Indexed: 11/06/2022]
Abstract
Catarrhine symphyseal morphology displays considerable variation. Although this has been related to dentition, phylogeny, sexual dimorphism, and facial orientation, most emphasis has been given to the functional significance of the symphysis to mechanical loading during mastication. The current state of knowledge regarding the mechanical significance of the symphysis is based on a combination of in vivo experimental and comparative studies on Macaca fascicularis. These approaches have provided considerable insight into the stereotypical patterns of loading in the symphyseal region during chewing and hypotheses related to the associated symphyseal morphologies. Finite element analysis (FEA) was used to assess how in silico manipulation translates into the mechanical loading hypotheses previously proposed experimentally. In particular, this study tests the form-function relationship of the symphysis of an adult M. fascicularis mandible during lateral transverse bending and dorsoventral shear of the mandibular symphysis, and a series of modified hypothetical morphologies including absence/presence of tori and variation in the inclination and depth of the symphysis. FEA results of this study support previous findings that stresses associated with lateral transverse bending and dorsoventral shear of the mandibular symphysis can be minimized via an increased labio-lingual thickness in the superior transverse torus, an oblique symphyseal inclination, and/or an increased symphyseal depth. The finding that reduction of strains related to lateral transverse bending and dorsoventral shear can be achieved through a number of different morphologies contributes to our understanding of the influence of morphological and/or developmental constraints, such as dental development, on symphyseal form.
Collapse
Affiliation(s)
- Olga Panagiotopoulou
- Structure and Motion Laboratory, Department of Veterinary Basic Sciences, The Royal Veterinary College, University of London, London, UK.
| | | |
Collapse
|
45
|
Cobb SN, Panagiotopoulou O. Balancing the spatial demands of the developing dentition with the mechanical demands of the catarrhine mandibular symphysis. J Anat 2011; 218:96-111. [PMID: 21158857 DOI: 10.1111/j.1469-7580.2010.01321.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
The superior transverse torus of the catarrhine mandible has been shown to effectively reduce bending at the symphysis during unilateral postcanine biting. While the adult superior transverse torus contains trabecular bone, the juvenile one is almost entirely filled by developing permanent incisors until their eruption. This study uses finite elements analysis (FEA) to investigate whether the presence of developing incisors in the juvenile symphysis increases strains on the superior transverse torus. Two FE models of a juvenile Macaca fascicularis mandible were created: one included all the developing teeth; the second was modified to remove the incisor tooth crypts by filling them with trabecular bone. The models were loaded identically to simulate static physiological unilateral biting on dp(4) and strain magnitudes, patterns and distributions of the two FE models were compared. The FEA results show a notable increase in strain magnitudes by up to 40% when the developing incisors are present. The results indicate that, in order to maintain the same symphyseal strain magnitudes during chewing, the presence of the incisors in the symphysis necessitates a larger superior transverse torus in the juvenile than would be required if the superior transverse torus did not house the developing incisors. These results highlight the adaptational balance of the symphyseal morphology throughout ontogeny between biomechanics and the spatial demands of the developing dentition. Based on the findings we therefore propose that the spatial requirements of the developing incisors during ontogeny can act as a constraint on the functional adaptation and subsequent adult morphology observed in the catarrhine mandibular symphysis.
Collapse
Affiliation(s)
- Samuel N Cobb
- Functional Morphology and Evolution Unit, Hull York Medical School, University of Hull, Hull, UK.
| | | |
Collapse
|
46
|
Panagiotopoulou O, Kupczik K, Cobb SN. The mechanical function of the periodontal ligament in the macaque mandible: a validation and sensitivity study using finite element analysis. J Anat 2011; 218:75-86. [PMID: 20584094 DOI: 10.1111/j.1469-7580.2010.01257.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Whilst the periodontal ligament (PDL) acts as an attachment tissue between bone and tooth, hypotheses regarding the role of the PDL as a hydrodynamic damping mechanism during intraoral food processing have highlighted its potential importance in finite element (FE) analysis. Although experimental and constitutive models have correlated the mechanical function of the PDL tissue with its anisotropic, heterogeneous, viscoelastic and non-linear elastic nature, in many FE simulations the PDL is either present or absent, and when present is variably modelled. In addition, the small space the PDL occupies and the inability to visualize the PDL tissue using μCT scans poses issues during FE model construction and so protocols for the PDL thickness also vary. In this paper we initially test and validate the sensitivity of an FE model of a macaque mandible to variations in the Young's modulus and the thickness of the PDL tissue. We then tested the validity of the FE models by carrying out experimental strain measurements on the same mandible in the laboratory using laser speckle interferometry. These strain measurements matched the FE predictions very closely, providing confidence that material properties and PDL thickness were suitably defined. The FE strain results across the mandible are generally insensitive to the absence and variably modelled PDL tissue. Differences are only found in the alveolar region adjacent to the socket of the loaded tooth. The results indicate that the effect of the PDL on strain distribution and/or absorption is restricted locally to the alveolar bone surrounding the teeth and does not affect other regions of the mandible.
Collapse
Affiliation(s)
- Olga Panagiotopoulou
- Functional Morphology and Evolution Unit, Hull York Medical School, University of York, UK.
| | | | | |
Collapse
|
47
|
Panagiotopoulou O, Curtis N, O'Higgins P, Cobb S. RETRACTED: Erratum to “Modelling subcortical bone in finite element analyses: A validation and sensitivity study in the macaque mandible” [J. Biomech. 43 (2010) 1603–1611]. J Biomech 2010. [DOI: 10.1016/j.jbiomech.2010.06.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
48
|
Panagiotopoulou O. Finite element analysis (FEA): Applying an engineering method to functional morphology in anthropology and human biology. Ann Hum Biol 2009; 36:609-23. [DOI: 10.1080/03014460903019879] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
|