The Effects of Mechanical Scale on Neural Control and the Regulation of Joint Stability

Recent work has demonstrated how the size of an animal can affect neural control strategies, showing that passive viscoelastic limb properties have a significant role in determining limb movements in small animals but are less important in large animals. We extend that work to consider effects of mechanical scaling on the maintenance of joint integrity; i.e., the prevention of aberrant contact forces within joints that might lead to joint dislocation or cartilage degradation. We first performed a literature review to evaluate how properties of ligaments responsible for joint integrity scale with animal size. Although we found that the cross-sectional area of the anterior cruciate ligament generally scaled with animal size, as expected, the effects of scale on the ligament’s mechanical properties were less clear, suggesting potential adaptations in passive contributions to the maintenance of joint integrity across species. We then analyzed how the neural control of joint stability is altered by body scale. We show how neural control strategies change across mechanical scales, how this scaling is affected by passive muscle properties and the cost function used to specify muscle activations, and the consequences of scaling on internal joint contact forces. This work provides insights into how scale affects the regulation of joint integrity by both passive and active processes and provides directions for studies examining how this regulation might be accomplished by neural systems.

Download Full-text

How flexible is the neural control of muscle properties?

Journal of Experimental Biology ◽

10.1242/jeb.115.1.393 ◽

1985 ◽

Vol 115 (1) ◽

pp. 393-402 ◽

Cited By ~ 1

Author(s):

V. R. Edgerton ◽

T. P. Martin ◽

S. C. Bodine ◽

R. R. Roy

Keyword(s):

Motor Unit ◽

Neural Control ◽

Succinic Dehydrogenase ◽

Neural System ◽

Muscle Fibres ◽

Muscle Proteins ◽

Muscle Properties ◽

Cross Sectional ◽

Glycerophosphate Dehydrogenase ◽

Metabolic Properties

The issue addressed in this paper is to what extent are selected physiological properties and associated protein systems of muscle fibres controlled or regulated by neuronal systems. One extreme position would be that all muscle proteins are controlled completely by the neural system that innervates the muscle. The opposite position would be that none of the muscle proteins are under neural influence. Although the concept that there is complete neural control of all proteins has generally received more support, it is more likely that there is only partial neural control of some proteins. Identical physiological, morphological and metabolic properties of all muscle fibres within a motor unit would suggest a complete neural control of all protein systems in muscle fibres. However, evidence against this idea is provided by the marked heterogeneity in the activities of two enzymes, alpha glycerophosphate dehydrogenase and succinic dehydrogenase (SDH), and in the wide variations in muscle fibre cross-sectional areas among fibres of the same motor unit in the cat soleus and tibialis anterior.

Download Full-text

An in vitro Comparison of Two Replacement Techniques Utilizing Fascia Lata after Cranial Cruciate Ligament Transection in the Dog

Veterinary and Comparative Orthopaedics and Traumatology ◽

10.1055/s-0038-1633025 ◽

1993 ◽

Vol 06 (02) ◽

pp. 85-92 ◽

Cited By ~ 3

Author(s):

G. L. Coetzee

Keyword(s):

Femoral Condyle ◽

Cruciate Ligament ◽

Maximum Load ◽

Fascia Lata ◽

Patellar Ligament ◽

Cross Sectional ◽

Cranial Cruciate Ligament ◽

Replacement Technique ◽

Over The Top

SummaryThe immediate postoperative biomechanical properties of an “underand-over” cranial cruciate ligament (CCL) replacement technique consisting of fascia lata and the lateral onethird of the patellar ligament, were compared with that of a modified intra- and extracapsular “under-and-over-the-top” (UOTT) method. The right CCL in twelve adult dogs was dissected out and replaced with an autograft. The contralateral, intact CCL served as the control. In group A, the graft was secured to the lateral femoral condyle with a spiked washer and screw. In group B the intracapsular graft was secured to the lateral femoro-fabellar ligament, and the remainder to the patellar tendon. Both CCL replacement techniques exhibited a 2.0 ± 0.5 mm anterior drawer immediately after the operation. After skeletonization of the stifles, the length and cross-sectional area of the intact CCL and CCL substitutes were determined. Each bone-ligament unit was tested in linear tension to failure at a fixed distraction rate of 15 mm/s with the stifle in 120° flexion. Data was processed to obtain the corresponding material parameters (modulus, stress and strain in the linear loading region, and energy absorption to maximum load).The immediate postoperative structural and material properties of the “under-and-over” cranial cruciate ligament replacement technique with autogenous fascia lata, were compared to that of a modified intra- and extracapsular “under-and-over-the-top” (UOTT) method. The combined UOT T technique was slightly stronger (6%), but allowed 2.8 ± 0.9 mm more cranial tibial displacement at maximum linear force.

Download Full-text

Biomechanical Properties of the Stifle Joint Lateral Collateral Ligament in Dogs

Veterinary and Comparative Orthopaedics and Traumatology ◽

10.1055/s-0038-1633103 ◽

1992 ◽

Vol 05 (04) ◽

pp. 158-162 ◽

Cited By ~ 1

Author(s):

D. Blackketter ◽

J Harari ◽

J. Dupuis

Keyword(s):

Mechanical Properties ◽

Cruciate Ligament ◽

Lateral Collateral Ligament ◽

Biomechanical Properties ◽

Fibular Head ◽

Joint Stability ◽

Collateral Ligament ◽

Cranial Cruciate Ligament ◽

Stifle Joint

Bone/lateral collateral ligament/bone preparations were tested and structural mechanical properties compared to properties of cranial cruciate ligament in 15 dogs. The lateral collateral ligament has sufficient stiffness to provide stifle joint stability and strength to resist acute overload following fibular head transposition.

Download Full-text

HIV/AIDS Knowledge and Risk-Taking Behaviours among Youths at a University in Enugu, Nigeria

Africa Journal of Nursing and Midwifery ◽

10.25159/2520-5293/3487 ◽

2018 ◽

Vol 20 (1) ◽

Author(s):

Ada C. Nwaneri ◽

Okwudili Callistus Ezike ◽

Agnes N. Anarado ◽

Ifeoma Ndubisi ◽

Jane-Lovena Onyia-Pat

Keyword(s):

Risk Taking ◽

Control Strategies ◽

Analysis Of Covariance ◽

Cross Sectional ◽

Awareness Campaigns ◽

South Eastern ◽

Risky Behaviours ◽

Aids Knowledge ◽

The University ◽

Hiv Aids

A national sentinel survey of 2006 shows that Enugu State in south-eastern Nigeria is the worst hit by HIV infections. Despite numerous control strategies having been implemented, the state was still reported by another national HIV sentinel survey in 2010 as the worst hit by HIV/AIDS within the zone, and that youths are the most affected. The researchers conducted a cross-sectional descriptive survey to assess the HIV/AIDS knowledge and risk-taking behaviours of youths at a federal university in Enugu, south-eastern Nigeria. They adopted a multistage sampling method to recruit 460 unmarried, consenting students between 15 and 30 years of age, from three faculties of the university. Almost 90 per cent of the university youths had a sound knowledge of key concepts related to HIV/AIDS; despite this, a subset (7.39%) still engaged in risk-taking behaviours. The major risky behaviours identified include having premarital sex, having multiple sexual partners, the sharing of shaving or razor blades, the use of public clippers and tribal marking. Although an analysis of variance demonstrated no significant relationship (t = −0.036) between university youths’ knowledge of HIV/AIDS and their related risk-taking behaviour, risky behaviours were found to be more (13%) among respondents who had insufficient or incorrect knowledge of the disease. An analysis of covariance, however, showed that gender and socio-economic backgrounds were not determinants of the HIV/AIDS risk-taking behaviours of these youths. Therefore, factors such as attitude or culture are areas that should be focused on, and should then, along with educational awareness campaigns, help to reduce the spread and prevalence of the disease.

Download Full-text

An Investigation of Knee Injury Profiles among Iranian Elite Karatekas: Observations from a Cross-Sectional Study

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph18136888 ◽

2021 ◽

Vol 18 (13) ◽

pp. 6888

Author(s):

Hamidreza Naserpour ◽

Julien S. Baker ◽

Amir Letafatkar ◽

Giacomo Rossettini ◽

Frédéric Dutheil

Keyword(s):

Knee Injury ◽

Cruciate Ligament ◽

Knee Injuries ◽

Cross Sectional Study ◽

Lower Extremity Injury ◽

Sectional Study ◽

Positive Health ◽

Sports Activity ◽

Cross Sectional ◽

National Team

Karate training, despite the many positive health benefits, carries a risk of injury for participants. The current cross-sectional study aimed to investigate knee injury profiles among Iranian elite karatekas. Participants who attended the national team qualifiers, which included 390 male Kumite karatekas (age 24 ± 3 years old and weight 63 ± 12 kg), participated in this study. Information on knee injuries (injury history, type of injury mechanisms, and effects of knee symptoms on the ability to perform daily activities and recreational activities) were obtained using the Knee Outcome Survey (KOS). Using Pearson’s correlation coefficient, the study examined the relationships between different variables, including KOS subscales and levels of self-reported knee joint function. Our findings indicated that 287 karatekas (73.6%) experienced knee injuries. The anterior cruciate ligament (ACL) rupture (6.9%), articular cartilage (5.4%), and meniscus damage (3.8%) were the main typology of injury. In addition, there were no differences in knee injuries between the non-dominant and dominant legs. Most injuries occurred during the preparatory period (n = 162, 50%), especially during training periods. The KOS subscales scores (Mean ± Sd) for activities of daily living (ADL) and sports activity (SAS) were, respectively, 89 ± 11 and 91 ± 9. The self-reported scores for both the ADL and SAS subscales were, respectively, 89 ± 11 and 90 ± 10. Pearson coefficients of ADL and SAS subscales with their self-reported score were r = 0.761 (p < 0.0001) and r = 0.782 and (p < 0.0001), respectively. The profile of knee injuries in the current investigation is similar to previous surveys that reported lower extremity injury patterns. The findings of this study could be adopted to inform practice aimed at planning interventions for the reduction and prevention of knee injuries among karatekas.

Download Full-text

Insight into One Health Approach: Endoparasite Infections in Captive Wildlife in Bangladesh

Pathogens ◽

10.3390/pathogens10020250 ◽

2021 ◽

Vol 10 (2) ◽

pp. 250

Author(s):

Tilak Chandra Nath ◽

Keeseon S. Eom ◽

Seongjun Choe ◽

Shahadat Hm ◽

Saiful Islam ◽

...

Keyword(s):

One Health ◽

Control Strategies ◽

Limited Resource ◽

Cross Sectional Study ◽

Cox1 Gene ◽

Parasite Control ◽

Cross Sectional ◽

Zoo Animals ◽

Health Concept ◽

Control Knowledge

Introduction: Endoparasites in captive wildlife might pose a threat to public health; however, very few studies have been conducted on this issue, and much remains to be learned, especially in limited-resource settings. This study aimed to investigate endoparasites of captive wildlife in Bangladesh. Perception and understanding of veterinarians regarding one health and zoonoses were also assessed. Materials and Methods: A cross-sectional study was conducted from October 2019 to August 2020. A total of 45 fecal samples from 18 different species of wild animals (i.e., 11 species of mammals: herbivores, carnivores, and omnivores, six birds, and a single reptile species) were collected randomly. Parasitological assessments were done by modified formalin ether sedimentation technique and rechecked by Sheather’s sugar floatation technique. Molecular identification of Spirometra spp. was conducted by amplifying the cytochrome c oxidase 1 (cox1) gene. Questionnaire surveys among 15 veterinarians and an in-depth interview (IDI) with a zoo officer were conducted. Results: Helminths (Spirometra sp., Capillaria sp., Ascaridia/Heterakis, opisthorchiid, strongyles, acuariid, hookworms, roundworms, and unidentified nematode larvae) and protozoa (coccidian oocyst) were identified, and the overall prevalence was 48.9% (22/45). The cox1 sequences (341 bp) of the Bangladesh-origin Spirometra species from lion showed 99.3–99.7% similarity to the reference sequences of Spirometra decipiens (GenBank No: KJ599679.1; MT122766). The majority of study participants (86.6%) agreed about the importance of endoparasite control in zoo animals, and 73.3% expressed that the one health concept should be promoted in Bangladesh. Only 6.7% of veterinarians perceived confidence in diagnosing parasitic diseases and preventing antiparasiticidal resistance. Conclusions: In the present survey, we found a considerable prevalence of endoparasites in captive wildlife. For the first time, zoonotically important S. decipiens from lion was molecularly characterized in Bangladesh. Veterinarian training is required to improve parasite control knowledge and practice. This study highlights the need for routine parasitological assessment, promotion of one health, and improvement of the implementation of current parasite control strategies in zoo animals.

Download Full-text

Risk factors associated with Ctenocephalides felis flea infestation of peri-urban goats: a neglected parasite in an under-appreciated host

Tropical Animal Health and Production ◽

10.1007/s11250-021-02620-7 ◽

2021 ◽

Vol 53 (1) ◽

Author(s):

Julia Rose Dahm ◽

Jordana Burdon Bailey ◽

Robert F. Kelly ◽

Patrick Chikungwa ◽

Julius Chulu ◽

...

Keyword(s):

Risk Factors ◽

Urban Communities ◽

Control Strategies ◽

Animal Health ◽

Animal Husbandry ◽

Ctenocephalides Felis ◽

Disease Spread ◽

Health Concern ◽

Cross Sectional ◽

Flea Infestation

AbstractGoats are critical in mixed smallholder agricultural systems in lower and middle-income countries, while fleas are important human and animal health concerns around the world. Convenience sampling was used to describe and consider risk factors for flea infestations of peri-urban goats, with the aim of informing the iterative development of animal husbandry and management based control strategies. Seven hundred and ninety-two goats were examined in 228 households across 10 peri-urban communities surrounding Blantyre in southern Malawi. The prevalence of Ctenocephalides felis fleas was 18.3, 37.1 and 100% at the levels of individual goats, households and communities, respectively, highlighting a neglected human and animal health concern. Constant introduction of new livestock coupled to a lack of biosecurity within communities, the ubiquitous presence of dog and cat hosts for C. felis, the frequency and thoroughness of cleaning overnight goat accommodation, and goat age less than 12 months old were identified as risk factors for flea infestation. This focal cross-sectional study highlights the significance of fleas in peri-urban communities and uncovers trends and commonalities that are needed to inform sustainable disease management. The majority of the peri-urban goat keepers were female, had resided in the same community throughout their whole life and had primary level education. Advice on the planned management of fleas in livestock needs to be tailored towards this demographic group. This approach affords an opportunity to promote public health measures to address household flea infestations and zoonotic disease spread.

Download Full-text

Seeing Beyond Morphology-Standardized Stress MRI to Assess Human Knee Joint Instability

Diagnostics ◽

10.3390/diagnostics11061035 ◽

2021 ◽

Vol 11 (6) ◽

pp. 1035

Author(s):

Eva-Maria Winkelmeyer ◽

Justus Schock ◽

Lena Marie Wollschläger ◽

Philipp Schad ◽

Marc Sebastian Huppertz ◽

...

Keyword(s):

Knee Joint ◽

Imaging Modality ◽

Cruciate Ligament ◽

Acl Injury ◽

Anterior Tibial Translation ◽

Joint Stability ◽

Anatomic Landmarks ◽

Human Knee Joint ◽

Custom Made ◽

Tibial Translation

While providing the reference imaging modality for joint pathologies, MRI is focused on morphology and static configurations, thereby not fully exploiting the modality’s diagnostic capabilities. This study aimed to assess the diagnostic value of stress MRI combining imaging and loading in differentiating partial versus complete anterior cruciate ligament (ACL)-injury. Ten human cadaveric knee joint specimens were subjected to serial imaging using a 3.0T MRI scanner and a custom-made pressure-controlled loading device. Emulating the anterior-drawer test, joints were imaged before and after arthroscopic partial and complete ACL transection in the unloaded and loaded configurations using morphologic sequences. Following manual segmentations and registration of anatomic landmarks, two 3D vectors were computed between anatomic landmarks and registered coordinates. Loading-induced changes were quantified as vector lengths, angles, and projections on the x-, y-, and z-axis, related to the intact unloaded configuration, and referenced to manual measurements. Vector lengths and projections significantly increased with loading and increasing ACL injury and indicated multidimensional changes. Manual measurements confirmed gradually increasing anterior tibial translation. Beyond imaging of ligament structure and functionality, stress MRI techniques can quantify joint stability to differentiate partial and complete ACL injury and, possibly, compare surgical procedures and monitor treatment outcomes.

Download Full-text