Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Torso”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 127 records · Page 7Linked to original sources
PubMed1989

Why is the lower torso protected in traumatic asphyxia? A new hypothesis.

Traumatic asphyxia secondary to a crush injury of the chest is characterized by craniocervical cyanosis, subconjunctival hemorrhage, and severe vascular engorgement of the head and neck. These signs are believed to be due to high venous pressures causing stasis and capillary rupture. A "fear response" that produces a strong Valsalva maneuver is thought to be necessary for their development. The lower torso seems to be protected, and previously this was thought to be due to its superior system of valves. We present here ultrasonographic evidence that the inferior vena cava is compressed or obliterated during a Valsalva maneuver, and propose that this compression protects the lower torso during traumatic asphyxia.

Abdomen↗
PubMed1989

A technique for assessment of torso kinesiology.

A technique is described for monitoring and analysis of the angular displacement of the human torso. The technique is based on the use of miniature electromechanical inclinometers and video recording. The system was developed for continuous measurement of the angular displacement of spinal segments in the sagittal plane during all stages of lifting. Angular displacements of the cervical, thoracic and lumbar regions were obtained from a dynamic lifting case study using a digital processing system. The geometrical changes of the torso during five prescribed stages were measured. The system revealed good accuracy with high correlation coefficient scores for a wide range of lifting tasks in a comparative laboratory study. This paper describes the monitoring technique; the system's advantages, disadvantages and measuring accuracy are discussed.

Journal Article↗
PubMed1987

Torso trauma.

This monograph represents an overview of torso trauma. The torso should be viewed as a single unit and injuries may affect the thoracic and abdominal viscera. My approach to the various injuries is pragmatic and usually fairly aggressive. The purpose is to reduce complications and missed injuries and it applies equally well to the surgeon whose practice is extensive or to the surgeon who treats only occasional injuries.

Abdominal Injuries↗
PubMed1986

Developmental analysis of the torso-like phenotype in Drosophila produced by a maternal-effect locus.

The segmental plan of the Drosophila embryo is already established at the blastoderm stage through the action of maternal effect genes which determine the polarity of the embryo and zygotically active genes involved in segmentation. We have analyzed the first example of a group of maternally acting genes which are necessary for establishing the developmental potential of the posterior 25% of the blastoderm. Females, homozygous for the X-linked maternal-effect mutation female sterile(1)Nasrat211 [fs(1)N211], produce embryos, characterized as torso-like, which lack all posterior endodermal derivatives as well as structures characteristic of abdominal segments 8 to 10. In addition, anterior endodermal derivatives are deficient and the absence of pharyngeal musculature causes a collapse of the cephalopharyngeal apparatus. The columnar blastoderm cell layer is defective at the posterior tip below the pole cells in these embryos. This defect, however, is presumably secondary to some abnormal feature of pole cell formation since in double mutants of fs(1)Nasrat211; tudor3 the blastoderm is normal but the embryos still show the torso-like phenotype. In situ hybridization with RNA probes derived from the fushi tarazu gene establishes that the cellular determination of the posterior blastoderm of embryos produced by fs(1)N211 is changed. This represents the first direct demonstration that a maternal-effect mutation alters the spatial distribution of a zygotic gene product involved in the segmental patterning of the embryo.

Alleles↗
PubMed1989

The effect of torso inhomogeneities on body surface potentials quantified using "tailored" geometry.

The effect of torso inhomogeneities on the electrocardiographic body surface potentials in general, and the waveform of the QRS complex in the standard leads in particular, were studied by using an inhomogeneous, numerical model of the torso including the (lower) conductivity of the lungs and the (higher) conductivity of the ventricular cavities. The relevant geometry was derived from actual data as measured from NMR scans of the subjects studied. The simulated potentials were compared to the body surface potentials recorded in the same individuals. In view of the observed high quality of the correspondence in the fully inhomogeneous case, the quantitative results of the study of the effects of the involved inhomogeneities attain a high level of credibility. To facilitate this analysis a new tool is introduced: the contribution maps.

Action Potentials↗
PubMed1995

The torso receptor tyrosine kinase can activate Raf in a Ras-independent pathway.

Activation of the receptor tyrosine kinase (RTK) torso defines the spatial domains of expression of the transcription factors tailless and huckebein. Previous analyses have demonstrated that Ras1 (p21ras) operates upstream of the D-Raf (Raf1) serine/threonine kinase in this signaling pathway. By using a recently developed technique of germline mosaics, we find that D-Raf can be activated by torso in the complete absence of Ras1. This result is supported by analysis of D-Raf activation in the absence of either the exchange factor Son of sevenless (Sos) or the adaptor protein drk (Grb2), as well as by the phenotype of a D-Raf mutation that abolishes binding of Ras1 to D-Raf. Our study provides in vivo evidence that Raf can be activated by an RTK in a Ras-independent pathway.

Animals↗
PubMed1990

Computer model of an inhomogeneous human torso.

Based on the atlas of sectional human anatomy, a three dimensional computer model of a human torso, including four cavities of the heart (LV, RV, LA, RA), two lobes of the lung and the body surface, and a three dimensional model of the myocardium is introduced. The torso model, with more than 10,000 surface triangles, depicts the structures and appropriate proportions of the internal organs, especially of the heart. Algorithms for the model construction are given in detail and the validity of the models for the purpose of simulation research into the electrocardiogram is discussed.

Algorithms↗
PubMed1995

Three-dimensional simulation of epicardial potentials using a microcomputer-based heart-torso model.

Previous cardiac simulation studies have focused on simulating the activation isochrones and subsequently the body surface potentials. Epicardial potentials, which are important for clinical applications as well as for electrocardiography inverse problem studies, however, have usually been neglected. This paper presents a procedure of simulating epicardial potentials using a microcomputer-based heart-torso model with real geometry. The heart model developed earlier which was composed of more than 60,000 cell units was used in this study. To simulate the epicardial potentials, an epicardial surface model which enclosed the whole heart was constructed. The heart model, together with the epicardial surface model, are mounted in an inhomogeneous human torso model. Electric dipoles, which are proportional to the spatial gradient of the action potential, are generated in all cell units. These dipoles give rise to a potential distribution on the epicardial surface, which is calculated by means of the boundary element method. The simulated epicardial potential maps during a normal heart beat and in patients with left bundle branch block (LBBB) are in close agreement with those reported in the literature.

Action Potentials↗
PubMed2006

Early predictors of prolonged mechanical ventilation in major torso trauma patients who require resuscitation.

BACKGROUND: The study purpose was to identify early predictors of prolonged mechanical ventilation in major torso trauma patients. METHODS: This was a retrospective review of torso trauma patients who met specific criteria for shock resuscitation and required 48 hours of mechanical ventilation. Independent variables evaluated included patient demographics, injury characteristics, and initial 24-hour resuscitation parameters. Univariate and multivariate logistic regression analyses were performed using a significance level of P <.05. RESULTS: Over 59 months, 224 patients met study criteria. Age was 34 years (range 25 to 69), 68% were male, 78% sustained blunt trauma, and injury severity score was 27 (range 18 to 38). Thirty-three percent required prolonged mechanical ventilation. In the analysis, predictors of prolonged mechanical ventilation included total fluid resuscitation, facial trauma, age, positive end-expiratory pressure > or =10 mm Hg on admission, arterial partial pressure of oxygen divided by the fraction of inspired oxygen ratio less than 300 at 24 hours, and chest abbreviated injury scale score. CONCLUSIONS: The need for prolonged mechanical ventilation can be accurately predicted and these predictors may assist clinicians in resource allocation and patient management decisions.

Adult↗
PubMed2006

Effects of different levels of torso coactivation on trunk muscular and kinematic responses to posteriorly applied sudden loads.

BACKGROUND: Studies examining rapid spine loading have documented the influence of steady-state trunk preloads, and the resulting levels of trunk muscle preactivation, on the control of spine stability. However, the effects of different levels of muscle coactivation, and resulting spine loads, on the response to a perturbation of the externally unloaded trunk are unclear. METHODS: Fourteen male subjects coactivated the abdominal muscles at four different levels (approximately 0%, 10%, 20% and 30% of the maximal voluntary contraction) monitored by an electromyography biofeedback system while semi-seated in a neutral lumbar spine position. They were loaded posteriorly in two directions (0 degrees and 30 degrees from the sagittal plane) and with two different loads (6.80 and 9.07 kg). Force perturbation, spine displacement and electromyography activity were measured, and torso compression and stability were modeled. FINDINGS: Abdominal coactivation significantly increased spine stability and reduced the movement of the lumbar spine after perturbation, but at the cost of increasing spinal compression. Preactivation also reduced the frequency and magnitude, and delayed the onset of muscle reactions, mainly for the back muscles and the internal oblique. The higher magnitude load and the load applied in an oblique direction both showed more potentially hazardous effects on the trunk. INTERPRETATION: Torso coactivation increases spinal stiffness and stability and reduces the necessity for sophisticated muscle responses to perturbation. Although further investigation is needed, it appears there is an asymptotic function between coactivation and both stiffness and stability. There also appears to be more hazard when buttressing twisting components of a sudden load compared to sagittal components. Patients with trunk instability and intolerance to spine compression may benefit from low to moderate levels of coactivation.

Abdominal Muscles↗
PubMed2005

Maternal torso signaling controls body axis elongation in a short germ insect.

In the long germ insect Drosophila, all body segments are determined almost simultaneously at the blastoderm stage under the control of the anterior, the posterior, and the terminal genetic system . Most other arthropods (and similarly also vertebrates) develop more slowly as short germ embryos, where only the anterior body segments are specified early in embryogenesis. The body axis extends later by the sequential addition of new segments from the growth zone or the tail bud . The mechanisms that initiate or maintain the elongation of the body axis (axial growth) are poorly understood . We functionally analyzed the terminal system in the short germ insect Tribolium. Unexpectedly, Torso signaling is required for setting up or maintaining a functional growth zone and at the anterior for the extraembryonic serosa. Thus, as in Drosophila, fates at both poles of the blastoderm embryo depend on terminal genes, but different tissues are patterned in Tribolium. Short germ development as seen in Tribolium likely represents the ancestral mode of how the primary body axis is set up during embryogenesis. We therefore conclude that the ancient function of the terminal system mainly was to define a growth zone and that in phylogenetically derived insects like Drosophila, Torso signaling became restricted to the determination of terminal body structures.

Animals↗
PubMed2005

Developmental evolution: torso--a story with different ends?

The Torso pathway patterns the ends of the Drosophila embryo. Now, it has been found to control axis elongation in the short germ insect Tribolium. This result raises the issue of the ancestral function of the Torso pathway and its evolution.

Animals↗
PubMed2005

An integrative model of mouse cardiac electrophysiology from cell to torso.

AIMS: Although the transgenic mouse has become an important new tool in the study of human diseases and the design of new therapies, a complete picture of cardiac electrophysiology in the mouse, from genome to body surface, is lacking. A computational model of the mouse heart is presented, which is used to study the impact of ion-channel and structural manipulations on the distributions of extracellular potentials on the heart and body surface. METHODS: A model of the mouse heart anatomy, fibre organization and torso geometry was constructed from DTMRI images. An anisotropic bidomain model, with a modified Pandit et al. model for the ionic currents, was used to represent the electrical properties of the tissue. Spatial heterogeneity in the ion currents was introduced by modulating the transient outward current. A sinus beat was simulated in hearts with different tissue and membrane properties and the extracellular potentials were computed at both the heart and body surface. RESULTS: The simulated transmembrane patterns in the heart, and the timing and morphology of the simulated ECG waveforms were consistent with experimental measurements. In addition, the patterns of activation and recovery and the waveforms of the corresponding ECG were found to be relatively insensitive to changes in cell type distribution and tissue anisotropy. CONCLUSION: Because of the small size of the heart, an integrative model of mouse electrophysiology can be simulated from cell to torso, enabling a new tool to study how extracellular signals might be used to detect molecular changes underlying an arrhythmogenic substrate.

Algorithms↗
PubMed2006

Torso flexion modulates stiffness and reflex response.

Neuromuscular factors that contribute to spinal stability include trunk stiffness from passive and active tissues as well as active feedback from reflex response in the paraspinal muscles. Trunk flexion postures are a recognized risk factor for occupational low-back pain and may influence these stabilizing control factors. Sixteen healthy adult subjects participated in an experiment to record trunk stiffness and paraspinal muscle reflex gain during voluntary isometric trunk extension exertions. The protocol was designed to achieve trunk flexion without concomitant influences of external gravitational moment, i.e., decouple the effects of trunk flexion posture from trunk moment. Systems identification analyses identified reflex gain by quantifying the relation between applied force disturbances and time-dependent EMG response in the lumbar paraspinal muscles. Trunk stiffness was characterized from a second order model describing the dynamic relation between the force disturbances versus the kinematic response of the torso. Trunk stiffness increased significantly with flexion angle and exertion level. This was attributed to passive tissue contributions to stiffness. Reflex gain declined significantly with trunk flexion angle but increased with exertion level. These trends were attributed to correlated changes in baseline EMG recruitment in the lumbar paraspinal muscles. Female subjects demonstrated greater reflex gain than males and the decline in reflex gain with flexion angle was greater in females than in males. Results reveal that torso flexion influences neuromuscular factors that control spinal stability and suggest that posture may contribute to the risk of instability injury.

Abdomen↗
PubMed1977

Effect of torso geometry on the magnetocardiogram.

Calculations of the effect of torso geometry on the extracorporeal magnetic field produced by a simple cardiac source have been carried out. Contrary to the results at present in the literature, it is found that the field solution is stable under perturbations of geometry in the sense that small relative changes in geometry produce comparably small changes in the magnetic field. Thus, simplified torso models may have a wider range of validity and usefulness than was previously thought.

Heart Function Tests↗
PubMed1998

Finite element analysis of defibrillation fields in a human torso model for ventricular defibrillation.

In order to optimize defibrillation electrode systems for ventricular defibrillation thresholds (DFTs), a Finite Element Torso model was built from fast CT scans of a patient who had large cardiac dimensions (upper bound of normal) but no heart disease. Clinically used defibrillation electrode configurations, i.e. Superior Vena Cava (SVC) to Right Ventricle (RV) (SVC-RV), left pectoral Can to RV (Can-RV) and Can + SVC-RV, were analyzed. The DFTs were calculated based on 95% ventricular mass having voltage gradient > 5 V/cm and these results were also compared with clinical data. The low voltage gradient regions with voltage gradient < 5 V/cm were identified and the effect of electrode dimension and location on DFTs were also investigated for each system. A good correlation between the model results and the clinical data supports the use of Finite Element Analysis of a human torso model for optimization of defibrillation electrode systems. This correlation also indicates that the critical mass hypothesis is the primary mechanism of defibrillation. Both the FEA results and the clinical data show that Can + SVC-RV system offers the lowest voltage DFTs when compared with SVC-RV and Can-RV systems. Analysis of the effect of RV, SVC and Can electrode dimensions and locations can have an important impact on defibrillation lead designs.

Computational Biology↗
PubMed2002

A Prolog-based centroid algorithm for isovolume extraction from finite element torso simulations.

Computer modeling and simulation of the human torso provides a rapid and non-invasive means to observe the effects of implanted defibrillators. The objective of this study was to improve a method of extracting data from an implanted defibrillator simulation for subsequent visualization. Electrical quantities, such as the potential and gradient fields, are computed at points throughout various regions of a three-dimensional (3-D) torso model via a finite element solution. Software is then implemented in the Prolog language to extract and visualize a subset of the data, from within any subregion of the model, satisfying a given declarative constraint. In past work, membership in these subsets had been determined solely by the electrical quantities at the vertices of the tetrahedral elements within the model along with an arbitrary choice made by the user. However, this study expands upon previous work to utilize an alternative means of classification, calculating the centroid of each tetrahedron and assigning electrical properties to these centroids based on the distances of each centroid to the four corners of the tetrahedron. After the modifications, it is expected that the extracted subsets of the model will represent the data in a more realistic and conservative manner and provide more insight into the process of defibrillation than previous methods of data extraction and visualization.

Algorithms↗
PubMed1998

Dissecting the mechanism of torso receptor activation.

Regulated activation of receptor tyrosine kinases depends both on the presence of the receptors at the cell surface and on the availability of their ligands. In Drosophila the torso (tor) tyrosine kinase receptor is distributed along the surface of the embryo but it is only activated at the poles by a diffusible extracellular ligand generated at each pole which is trapped by the receptor, thereby impeding further diffusion. However, it is not well understood how this signal is generated, although it is known to depend on the activity of many genes such as torso-like (tsl) and trunk (trk). To further investigate the mechanism involved in the local activation of the tor receptor we have altered the normal expression of the tsl protein by generating females in which the tsl gene is expressed in the oocyte under the control of the tor promoter rather than in the ovarian follicle cells. Analysis of the phenotypes generated by this hybrid gene and its interactions with mutations in other genes in the pathway has enabled us to further dissect the mechanism of tor receptor activation and to define more precisely the role of the different genes acting in this process.

Animals↗