Occlusal Movements of the Brushtail Possum, Trichosurus-Vulpecula, From Microwear on the Teeth

This study characterises the jaw movements of the brushtail possum, Trichosurus vulpecula, from an analysis of microwear on the premolar and molar teeth. From 10 skulls of T, vulpecula, micrographs of tooth replicas which exhibitied progressive degrees of dental wear were examined for the location of wear facets and the orientation of striae on them. These data were transferred to transparencies overlying occlusal photographs of the jaws. Two movements, a vertical sectorial movement in the premolars segment and an anteromedial shearing and grinding stroke in the molar segment, were inferred. The directions of wear striations with respect to the sagittal plane supported the concept that the mandible rotates around the contralateral condyle from the working side. No evidence of balancing contact facets were found on the teeth of the contralateral side, in agreement with an anisognathous jaw movement. Videoradiographic observations of the chewing cycle of one brush-tailed possum confirmed that puncture crushing is employed early in the chewing cycle, followed by an anisognathous labiolingual transit of the mandibular molars. However, the resolution of the condyle by videoradiography was insufficient to determine the point of rotation of the jaw movements.

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Development of 2-D Jaw Movement Simulator (JSN/S1)

Journal of Robotics and Mechatronics ◽

10.20965/jrm.1998.p0499 ◽

1998 ◽

Vol 10 (6) ◽

pp. 499-504 ◽

Cited By ~ 5

Author(s):

Shin-ichi Nakajima ◽

◽

Toyohiko Hayashi ◽

Hiroshi Kobayashi ◽

◽

...

Keyword(s):

Degrees Of Freedom ◽

Sagittal Plane ◽

Jaw Movements ◽

Occlusal Force ◽

Neural Network Learning ◽

Jaw Movement ◽

Network Learning ◽

Control Scheme ◽

Muscle Actuators ◽

Dc Servomotor

Human mastication is performed by coordinated activities of several jaw muscles. To clarify functions of these muscles, we developed a jaw movement simulator (JSN/Sl) consisting of a 2 degrees of freedom (2DOF) mechanism and five muscle actuators able to reproduce jaw movements on a sagittal plane. The actuator is a cable-tendon driven by a DC servomotor controlled by a compliance control scheme to obtain viscoelastic muscle characteristics. To simulate life-like clenching, we controlled occlusal position and force by incorporating position and force sensors, using neural network learning control. Occlusal force successfully converged to a desired value through learning. Tension patterns of muscle actuators during clenching well coincided with human jaw activities.

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Nitrogen Requirements and Urea Metabolism in Two Arboreal Marsupials, the Greater Glider (Petauroides volans) and the Brushtail Possum (Trichosurus vulpecula), Fed Eucalyptus Foliage

Physiological Zoology ◽

10.1086/physzool.60.2.30158648 ◽

1987 ◽

Vol 60 (2) ◽

pp. 241-250 ◽

Cited By ~ 35

Author(s):

W. J. Foley ◽

I. D. Hume

Keyword(s):

Brushtail Possum ◽

Trichosurus Vulpecula ◽

Arboreal Marsupials ◽

Urea Metabolism

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Preovulatory follicle development and ovulation in the brushtail possum (Trichosurus vulpecula) monitored by repeated laparoscopy

Reproduction ◽

10.1530/jrf.0.1100361 ◽

1997 ◽

Vol 110 (2) ◽

pp. 361-370 ◽

Cited By ~ 21

Author(s):

J. L. Crawford ◽

G. H. Shackell ◽

E. G. Thompson ◽

B. J. McLeod ◽

P. R. Hurst

Keyword(s):

Brushtail Possum ◽

Follicle Development ◽

Trichosurus Vulpecula ◽

Preovulatory Follicle

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Increased protection against bovine tuberculosis in the brushtail possum (Trichosurus vulpecula) when BCG is administered with killed Mycobacterium vaccae

Tuberculosis ◽

10.1054/tube.2001.0318 ◽

2002 ◽

Vol 82 (1) ◽

pp. 15-22 ◽

Cited By ~ 18

Author(s):

M.A. Skinner ◽

D.L. Keen ◽

N.A. Parlane ◽

G.F. Yates ◽

B.M. Buddle

Keyword(s):

Bovine Tuberculosis ◽

Brushtail Possum ◽

Trichosurus Vulpecula ◽

Mycobacterium Vaccae

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Contact patterns as a risk factor for bovine tuberculosis infection in a free-living adult brushtail possum Trichosurus vulpecula population

Preventive Veterinary Medicine ◽

10.1016/j.prevetmed.2011.03.014 ◽

2011 ◽

Vol 100 (3-4) ◽

pp. 221-230 ◽

Cited By ~ 15

Author(s):

T. Porphyre ◽

J. McKenzie ◽

M.A. Stevenson

Keyword(s):

Risk Factor ◽

Bovine Tuberculosis ◽

Tuberculosis Infection ◽

Brushtail Possum ◽

Trichosurus Vulpecula ◽

Free Living ◽

Contact Patterns ◽

Living Adult

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Expression of the FcRn receptor (α and β) gene homologues in the intestine of suckling brushtail possum (Trichosurus vulpecula) pouch young

Molecular Immunology ◽

10.1016/s0161-5890(02)00260-2 ◽

2003 ◽

Vol 39 (12) ◽

pp. 707-717 ◽

Cited By ~ 9

Author(s):

A.H Western ◽

D.C Eckery ◽

J Demmer ◽

J.L Juengel ◽

K.P McNatty ◽

...

Keyword(s):

Brushtail Possum ◽

Trichosurus Vulpecula

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In Vitro Hepatic Assessment of Cineole and Its Derivatives in Common Brushtail Possums (Trichosurus vulpecula) and Rodents

Biology ◽

10.3390/biology10121326 ◽

2021 ◽

Vol 10 (12) ◽

pp. 1326

Author(s):

Ravneel R. Chand ◽

Mhairi Nimick ◽

Belinda Cridge ◽

Rhonda J. Rosengren

Keyword(s):

Catalytic Activity ◽

Management Strategies ◽

Brushtail Possum ◽

Trichosurus Vulpecula ◽

Cytochrome P450 3A ◽

Phascolarctos Cinereus ◽

Catalytic Activities ◽

Rats And Mice ◽

Drug Metabolising Enzymes

Folivore marsupials, such as brushtail possum (Trichosurus Vulpecula) and koala (Phascolarctos cinereus), can metabolise higher levels of dietary terpenes, such as cineole, that are toxic to eutherian mammals. While the highly efficient drug metabolising enzymes, cytochrome P450 3A (CYP3A) and phase II conjugating enzymes (UDP-glucuronosyltransferase, UGT), are involved in the metabolism of high levels of dietary terpenes, evidence for inhibitory actions on these enzymes by these terpenes is scant. Thus, this study investigated the effect of cineole and its derivatives on catalytic activities of hepatic CYP3A and UGT in mice, rats, and possums. Results showed that cineole (up to 50 µM) and its derivatives (up to 25 µM) did not significantly inhibit CYP3A and UGT activities in mice, rats, and possums (both in silico and in vitro). Interestingly, basal hepatic CYP3A catalytic activity in the possums was ~20% lower than that in rats and mice. In contrast, possums had ~2-fold higher UGT catalytic activity when compared to mice and rats. Thus, these basal enzymatic differences may be further exploited in future pest management strategies.

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A Novel Technique to Assess Rotational Deformities in Lower Extremities

10.21203/rs.3.rs-115250/v1 ◽

2020 ◽

Author(s):

Peyman Bakhshayesh ◽

Ugwunna Ihediwa ◽

Sukha Sandher ◽

Alexandros Vris ◽

Nima Heidari ◽

...

Keyword(s):

Moving Objects ◽

Sagittal Plane ◽

Three Dimensional ◽

Contralateral Side ◽

Ct Images ◽

New Technique ◽

X Rays ◽

Digital Technique ◽

The Right ◽

Im Nailing

Abstract Introduction: Rotational deformities following IM nailing of tibia has a reported incidence of as high as 20%. Common techniques to measure deformities following IM nailing of tibia are either based on clinical assessment, plain X-rays or CT-scan comparing the treated leg with the uninjured contralateral side. All these techniques are based on examiners manual calculation inherently subject to bias. Following our previous rigorous motion analysis and symmetry studies on hemi pelvises, femurs and orthopaedic implants, we aimed to introduce a novel fully digital technique to measure rotational deformities in the lower legs.Material and Methods: Following formal institutional approval from the Imperial College, CT images of 10 pairs of human lower legs were retrieved. Images were anonymized and uploaded to a research server. Three dimensional CT images of the lower legs were bilaterally reconstructed. The mirrored images of the left side were merged with the right side proximally as stationary and distally as moving objects. Discrepancies in translation and rotation were automatically calculated.Results: Our study population had a mean age of 54 ± 20 years. There were six males and four females. We observed a greater variation in translation (mm) of Centre of Mass (COM) in sagittal plane (CI: -2.959--.292) which was also presented as rotational difference alongside the antero-posterior direction or Y axis (CI: .370-1.035). In other word the right lower legs in our study were more likely to be in varus compared to the left side. However, there were no statistically significant differences in coronal or axial planes.Conclusion: Using our proposed fully digital technique we found that lower legs of the human adults were symmetrical in axial and coronal plane. We found sagittal plane differences which need further addressing in future using bigger sample size. Our novel recommended technique is fully digital and commercially available. This new technique can be useful in clinical practice addressing rotational deformities following orthopaedic surgical intervention. This new technique can substitute the previously introduced techniques.

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