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- Cauda equina redundant nerve roots are associated to the degree of spinal stenosis and to spondylolisthesis. [JOURNAL ARTICLE]
- Arq Neuropsiquiatr 2014 Oct; 72(10):782-787.
To evaluate the association of redundant nerve roots of cauda equina (RNRCE) with the degree of lumbar spinal stenosis (LSS) and with spondylolisthesis. Method After Institutional Board approval, 171 consecutive patients were retrospectively enrolled, 105 LSS patients and 66 patients without stenosis. The dural sac cross-sectional area (CSA) was measured on T2w axial MRI at the level of L2-3, L3-4 and L4-5 intervertebral discs. Two blinded radiologists classified cases as exhibiting or not RNRCE in MRI. Intra- and inter-observer reproducibility was assessed. Results RNRCE were associated with LSS. RRNCE was more frequent when maximum stenosis<55 mm2. Substantial intra- observer agreement and moderate inter-observer agreement were obtained in the classification of RNRCE. Spondylolisthesis was identified in 27 patients and represented increased risk for RRNCE. Conclusion LSS is a risk factor for RNRCE, especially for dural sac CSA<55 mm2. LSS and spondylolisthesis are independent risk factors for RNRCE.
- Shifts in stability and control effectiveness during evolution of Paraves support aerial maneuvering hypotheses for flight origins. [Journal Article]
- PeerJ 2014.:e632.
The capacity for aerial maneuvering was likely a major influence on the evolution of flying animals. Here we evaluate consequences of paravian morphology for aerial performance by quantifying static stability and control effectiveness of physical models for numerous taxa sampled from within the lineage leading to birds (Paraves). Results of aerodynamic testing are mapped phylogenetically to examine how maneuvering characteristics correspond to tail shortening, forewing elaboration, and other morphological features. In the evolution of Paraves we observe shifts from static stability to inherently unstable aerial planforms; control effectiveness also migrated from tails to the forewings. These shifts suggest that a some degree of aerodynamic control and capacity for maneuvering preceded the evolution of a strong power stroke. The timing of shifts also suggests features normally considered in light of development of a power stroke may play important roles in control.
- Fundamental fluid transport mechanisms through articular cartilage. [Journal Article, Research Support, U.S. Gov't, Non-P.H.S.]
- Ann Rheum Dis 1975 Dec.:Suppl 82-4.
A unified self-consistent set of equations governing the fundamental fluid transport mechanisms through articular cartilage is described. These equations include Darcy's law for fluid flow through a permeable medium and Biot's consolidation equations for a fluid-filled elastically deformable permeable solid matrix. Kinematical, mechanical, and geometrical parameters which are important in the understanding of the biomechanics of normal and pathological articular cartilage are identified. Clearly, the present investigation is inchoate in that many of the mechanical and physical constants associated with articular cartilage are as yet unknown and imprecisely defined. Thus only a parametric study has been reported. It was found that in normal, healthy human articular cartilage during normal function the mechanical pumping mechanism dominated the processes of interstitial fluid transport, with the direct fluid pressure mechanism being the mode of fluid transport in the transitory phase of flow reversal. Further, upon load application the interstitial fluid was exuded across the articular surface directly under the load, and upon load removal the fluid was then imbibed under the load. Finally it was found that after one complete cycle there was a very small amount of net flux of fluid into the tissue.
- Calcitonin controls bone formation by inhibiting the release of sphingosine 1-phosphate from osteoclasts. [JOURNAL ARTICLE]
- Nat Commun 2014.:5215.
The hormone calcitonin (CT) is primarily known for its pharmacologic action as an inhibitor of bone resorption, yet CT-deficient mice display increased bone formation. These findings raised the question about the underlying cellular and molecular mechanism of CT action. Here we show that either ubiquitous or osteoclast-specific inactivation of the murine CT receptor (CTR) causes increased bone formation. CT negatively regulates the osteoclast expression of Spns2 gene, which encodes a transporter for the signalling lipid sphingosine 1-phosphate (S1P). CTR-deficient mice show increased S1P levels, and their skeletal phenotype is normalized by deletion of the S1P receptor S1P3. Finally, pharmacologic treatment with the nonselective S1P receptor agonist FTY720 causes increased bone formation in wild-type, but not in S1P3-deficient mice. This study redefines the role of CT in skeletal biology, confirms that S1P acts as an osteoanabolic molecule in vivo and provides evidence for a pharmacologically exploitable crosstalk between osteoclasts and osteoblasts.
- The Achilles tendon: fundamental properties and mechanisms governing healing. [Journal Article, Review]
- Muscles Ligaments Tendons J 2014 Apr; 4(2):245-55.
This review highlights recent research on Achilles tendon healing, and comments on the current clinical controversy surrounding the diagnosis and treatment of injury. The processes of Achilles tendon healing, as demonstrated through changes in its structure, composition, and biomechanics, are reviewed. Finally, a review of tendon developmental biology and mechano transductive pathways is completed to recognize recent efforts to augment injured Achilles tendons, and to suggest potential future strategies for therapeutic intervention and functional tissue engineering. Despite an abundance of clinical evidence suggesting that current treatments and rehabilitation strategies for Achilles tendon ruptures are equivocal, significant questions remain to fully elucidate the basic science mechanisms governing Achilles tendon injury, healing, treatment, and rehabilitation.
- Robotics in shoulder rehabilitation. [Journal Article, Review]
- Muscles Ligaments Tendons J 2014 Apr; 4(2):207-13.
In the last few decades, several researches have been conducted in the field of robotic rehabilitation to meet the intensive, repetitive and task-oriented training, with the goal to recover the motor function. Up to now, robotic rehabilitation studies of the upper extremity have generally focused on stroke survivors leaving less explored the field of orthopaedic shoulder rehabilitation. In this review we analyse the present status of robotic technologies, in order to understand which are the current indications and which may be the future perspective for their application in both neurological and orthopaedic shoulder rehabilitation.
- Assessment of the ability of wheelchair subjects with spinal cord injury to perform a specific protocol of shoulder training: a pilot study. [Journal Article]
- Muscles Ligaments Tendons J 2014 Apr; 4(2):165-76.
a regular program of exercises in subjects with spinal cord injury (SCI) can contribute to reduce the risk of upper extremities injuries.in this prospective laboratory study we tested the hypothesis that a training machine developed for able-body users is suitable for a shoulder training protocol in 11 paraplegic subjects with SCI. Overall subjects were assessed with the SCIM III, CS, DASH and standard shoulder examination. We set a protocol of shoulder exercises performed with a training machine. Overall subjects were able to perform the protocol but 2 did not complete the exercises n° 6 and 7. The position of the wheelchair during each exercise was recorded. Wheelchair position/loading level were significantly correlated with the protocol n° 2, 3 and 5 as well as BMI/loading level for the exercises n° 5 and 9 and age/loading level for the exercise n° 7. Clinical scores were neither correlated with loading nor with anthropometric data.FROM THE ANALYSIS OF DATA COLLECTED IN THIS STUDY ARISED THAT: 1) the training machine needs some adjustments for paraplegic subjects, 2) the training protocol was appropriate except for the exercises needing a torso-rotation and 3) the template for wheelchair position may be a valid guide for an optimal paraplegic shoulder training.
- Walking and running on treadmill: the standard criteria for kinematics studies. [Journal Article, Review]
- Muscles Ligaments Tendons J 2014 Apr; 4(2):159-62.
In humans, walking and running represent the most studied locomotion forms. The motorized treadmill has always been a very useful scientific tool, because it allows administer a variety of speed/slope combinations, which is not always easy-to-find in nature. The purpose of this short communication is to help improve the scientific use of the treadmill and explain some simple kinematics variables together with simple ways to measure/calculate them.
- Biomechanical design of Less Invasive Stabilization System femoral plates: Computational evaluation of the fracture environment. [JOURNAL ARTICLE]
- Proc Inst Mech Eng H 2014 Oct 20.
Less Invasive Stabilization System femoral plates are currently accepted as a suitable fixation technique for supra-intercondylar femoral fractures. However, general agreement does not exist regarding the optimum design of this fixator type. Therefore, the aim of this article is to reduce the intrinsic Less Invasive Stabilization System complications by clarifying, from a biomechanical point of view, how the number of screws, the screw connection type (unicortical or bicortical), or the structured position of the screws can influence the outcome of the fracture site. These studies include a specific finite element analysis that determines how several biomechanical variables, such as the movement at the fracture site, are influenced by the preconditions of bone healing. The results of this study show that the screw type affects the mechanical stabilization of the femur to a greater extent than the material type of the Less Invasive Stabilization System femoral plates. The most significant differences among all the analyzed configurations are observed in the shear interfragmentary strain between screw types. Values are approximately 50% higher with unicortical screws than with bicortical ones.
- The influence of different footwear on 3-D kinematics and muscle activation during the barbell back squat in males. [JOURNAL ARTICLE]
- Eur J Sport Sci 2014 Oct 21.:1-8.
Abstract The barbell back squat is commonly used by athletes participating in resistance training. The barbell squat is typically performed using standard athletic shoes, or specially designed weightlifting footwear, although there are now a large number of athletes who prefer to squat barefoot or in barefoot-inspired footwear. This study aimed to determine how these footwear influence 3-D kinematics and muscle activation potentials during the barbell back squat. Fourteen experienced male participants completed squats at 70% 1 rep max in each footwear condition. 3-D kinematics from the torso, hip, knee and ankle were measured using an eight-camera motion analysis system. In addition, electromyographical (EMG) measurements were obtained from the rectus femoris, tibialis anterior, gastrocnemius, erector spinae and biceps femoris muscles. EMG parameters and joint kinematics were compared between footwear using repeated-measures analyses of variance. Participants were also asked to subjectively rate which footwear they preferred when performing their squat lifts; this was examined a chi-squared test. The kinematic analysis indicated that, in comparison to barefoot the running shoe was associated with increased squat depth, knee flexion and rectus femoris activation. The chi-squared test was significant and showed that participants preferred to squat barefoot. This study supports anecdotal evidence of athletes who prefer to train barefoot or in barefoot-inspired footwear although no biomechanical evidence was found to support this notion.