271 research outputs found
Clinical, Biomechanical, and Physiological Translational Interpretations of Human Resting Myofascial Tone or Tension
Background: Myofascial tissues generate integrated webs and networks of passive and active tensional forces that provide stabilizing support and that control movement in the body. Passive [central nervous system (CNS)âindependent] resting myofascial tension is present in the body and provides a low-level stabilizing component to help maintain balanced postures. This property was recently called âhuman resting myofascial toneâ (HRMT). The HRMT model evolved from electromyography (EMG) research in the 1950s that showed lumbar muscles usually to be EMG-silent in relaxed gravity-neutral upright postures.
Methods: Biomechanical, clinical, and physiological studies were reviewed to interpret the passive stiffness properties of HRMT that help to stabilize various relaxed functions such as quiet balanced standing. Biomechanical analyses and experimental studies of the lumbar multifidus were reviewed to interpret its passive stiffness properties. The lumbar multifidus was illustrated as the major core stabilizing muscle of the spine, serving an important passive biomechanical role in the body.
Results: Research into muscle physiology suggests that passive resting tension (CNS-independent) is generated in sarcomeres by the molecular elasticity of low-level cycling cross-bridges between the actomyosin filaments. In turn, tension is complexly transmitted to intimately enveloping fascial matrix fibrils and other molecular elements in connective tissue, which, collectively, constitute the myofascial unit. Postural myofascial tonus varies with age and sex. Also, individuals in the population are proposed to vary in a polymorphism of postural HRMT. A few people are expected to have outlier degrees of innate postural hypotonicity or hypertonicity. Such biomechanical variations likely predispose to greater risk of related musculoskeletal disorders, a situation that deserves greater attention in clinical practice and research. Axial myofascial hypertonicity was hypothesized to predispose to ankylosing spondylitis. This often-progressive deforming condition of vertebrae and sacroiliac joints is characterized by stiffness features and particular localization of bony lesions at entheseal sites. Such unique features imply concentrations and transmissions of excessive force, leading to tissue micro-injury and maladaptive repair reactions.
Conclusions: The HRMT model is now expanded and translated for clinical relevance to therapists. Its passive role in helping to maintain balanced postures is supported by biomechanical principles of myofascial elasticity, tension, stress, stiffness, and tensegrity. Further research is needed to determine the molecular basis of HRMT in sarcomeres, the transmission of tension by the enveloping fascial elements, and the means by which the myofascia helps to maintain efficient passive postural balance in the body. Significant deficiencies or excesses of postural HRMT may predispose to symptomatic or pathologic musculoskeletal disorders whose mechanisms are currently unexplained
Acute ST-segment elevation myocardial infarction in a young patient with essential thrombocythemia: a case with long-term follow-up report
Essential thrombocythemia (ET) is a neoplastic proliferation of mature myeloid cells - in particular, megakaryocytes - leading to persistently elevated platelet count. Usual clinical presentation is related to an increase in the risk of hemorrhage and/or thrombosis. Management of ET consists of antiplatelet therapies - mainly aspirin and cytoreductive therapies. Coronary involvement in patients with ET is rare. The optimal treatment strategies for ET patients presenting with acute myocardial infarction remains unclear. Acute interventions like intracoronary thrombolytic therapy, angioplasty, and coronary-artery bypass grafting have been reported in such patients. However, several questions remain unanswered about the acute and long-term management of these patients. Herein, we report the case of a 47-year-old female who presented with acute myocardial infarction as the first clinical sign of ET, and also present the long-term follow-up of this patient
TexturalMineralogical and Microfacies Characteristics of the Lower Plaeogene Succesion at the nile valley and Kharga Oasis RegionsCentral Egypt
Petrography and Geochemistry of the Lower Paleozoic Araba Formation, Northern Eastern Desert, Egypt : Implications for Provenance, Tectonic Setting and Weathering Signature
Simultaneous genotyping and species identification using hybridization pattern recognition analysis of generic Mycobacterium DNA arrays
High-density oligonucleotide arrays can be used to rapidly examine large amounts of DNA sequence in a high throughput manner. An array designed to determine the specific nucleotide sequence of 705 bp of the rpoB gene of Mycobacterium tuberculosis accurately detected rifampin resistance associated with mutations of 44 clinical isolates of M. tuberculosis. The nucleotide sequence diversity in 121 Mycobacterial isolates (comprised of 10 species) was examined by both conventional dideoxynucleotide sequencing of the rpoB and 165 genes and by analysis of the rpoB oligonucleotide array hybridization patterns. Species identification for each of the isolates was similar irrespective of whether 16S sequence, rpoB sequence, or the pattern of rpoB hybridization was used. However, for several species, the number of alleles in the 16S and rpoB gene sequences provided discordant estimates of the genetic diversity within a species. In addition to confirming the array's intended utility for sequencing the region of M. tuberculosis that confers rifampin resistance, this work demonstrates that this array can identify the species of nontuberculous Mycobacteria. This demonstrates the general point that DNA microarrays that sequence important genomic regions (such as drug resistance or pathogenicity islands) can simultaneously identify species and provide some insight into the organism's population structure
Implications of invariance of the Hamiltonian under canonical transformations in phase space
We observe that, within the effective generating function formalism for the
implementation of canonical transformations within wave mechanics, non-trivial
canonical transformations which leave invariant the form of the Hamilton
function of the classical analogue of a quantum system manifest themselves in
an integral equation for its stationary state eigenfunctions. We restrict
ourselves to that subclass of these dynamical symmetries for which the
corresponding effective generating functions are necessaarily free of quantum
corrections. We demonstrate that infinite families of such transformations
exist for a variety of familiar conservative systems of one degree of freedom.
We show how the geometry of the canonical transformations and the symmetry of
the effective generating function can be exploited to pin down the precise form
of the integral equations for stationary state eigenfunctions. We recover
several integral equations found in the literature on standard special
functions of mathematical physics. We end with a brief discussion (relevant to
string theory) of the generalization to scalar field theories in 1+1
dimensions.Comment: REVTeX v3.1, 13 page
Hamiltonian quantization of General Relativity with the change of signature
We show in this article how the usual hamiltonian formalism of General
Relativity should be modified in order to allow the inclusion of the Euclidean
classical solutions of Einstein's equations. We study the effect that the
dynamical change of signature has on the superspace and we prove that it
induces a passage of the signature of the supermetric from () to
(). Next, all these features are more particularly studied on the
example of minisuperspaces. Finally, we consider the problem of quantization of
the Euclidean solutions. The consequences of different choices of boundary
conditions are examined.Comment: 32 pages, GCR-93/11/01, To appear in Phys. Rev.
Quantum equivalence of sigma models related by non Abelian Duality Transformations
Coupling constant renormalization is investigated in 2 dimensional sigma
models related by non Abelian duality transformations. In this respect it is
shown that in the one loop order of perturbation theory the duals of a one
parameter family of models, interpolating between the SU(2) principal model and
the O(3) sigma model, exhibit the same behaviour as the original models. For
the O(3) model also the two loop equivalence is investigated, and is found to
be broken just like in the already known example of the principal model.Comment: As a result of the collaboration of new authors the previously
overlooked gauge contribution is inserted into eq.(43) changing not so much
the formulae as part of the conclusion: for the models considered non Abelian
duality is OK in one loo
TCT-378 Not Every TEE Is a âStandard of Careâ TEE
Background: Intraprocedural structural heart imaging is more challenging and has unique differences from standard of care (SOC) imaging. However, the variations in time and complexity of different types of SOC transesophageal echocardiographs (TEEs) versus interventional TEEs is not well studied. In this study, we aim to compare the complexity of SOC nonvalvular indication TEE with SOC valvular TEE studies and interventional TEEs performed in the guidance of transcatheter edge-to-edge repair (TEER) MitraClip (Abbott Vascular) procedures.
Methods: A retrospective case-control analysis was performed on 200 patients who underwent TEE in the Henry Ford Health System. One hundred cases of interventional TEE-guided TEER were compared with 73 nonvalvular (endocarditis and stroke evaluation) SOC TEEs and 27 valvular (preprocedural mitral, aortic, and tricuspid valve evaluations) SOC TEEs. Complexity was quantified by the total procedure duration, the total number of images, and the number of 3-dimensional (3D) clips captured. The mean, median, and SD were compared between these groups. The Kruskal-Wallis test was used to evaluate statistical significance.
Results: The mean duration of TEE procedures, the number of images, and the number of 3D clips were all significantly higher in the interventional imaging TEER group compared with the noninterventional groups (P \u3c 0.0001) (Table 1). The duration and number of images were also significantly higher among valvular compared with nonvalvular SOC TEE groups (P \u3c 0.0002) as well as number of 3D clips (P \u3c 0.0012).
Conclusion: Interventional TEE was more complicated and time-consuming compared with SOC TEE performed for both nonvalvular and valvular indications. The latter was also more complex than SOC nonvalvular TEE. This is the first study of its kind demonstrating objective differences between interventional and 2 SOC TEE groups. These results emphasize the need of dedicated training for intraprocedural imaging as well as restructuring of reimbursement codes.
Categories: STRUCTURAL: Valvular Disease: Mitra
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