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PubMed1994

Simultaneous ST-segment measurements using standard and monitoring-compatible torso limb lead placements at rest and during coronary occlusion.

Electrocardiographic recordings used to assess ST-segment deviation are performed using both standard and torso limb lead positions, where bony prominences give more artifact-free signal. Whereas significant QRS artifact can be introduced by such changes in lead location, the impact on ST-segment measurements has never been assessed. Digital electrocardiographic recordings were performed in 29 patients throughout elective angioplasty balloon inflation in the left anterior descending (n = 12), right coronary (n = 14), and circumflex (n = 3) arteries. In all cases, unipolar leads V1, V4, and V6 were affixed to the torso lead positions, allowing reconstruction of simultaneously acquired standard and modified 9-lead electrocardiograms (ECGs). ST levels in the 26 patients who had ST deviation during angioplasty were compared at both baseline and peak ischemia of up to 1,046 microV in the anterior, and 551 microV in the inferior leads. Differences in recorded ST levels for modified versus standard lead locations were all < 100 microV, even at peak ischemia. Although ST-segment elevation in the inferior leads appeared to show slightly more pronounced differences between lead sets than did anterior elevation, all differences were < 100 microV. Thus, measurement of ST-segment levels appears unlikely to be importantly affected by the intermixture of ECGs recorded with standard lead positions and ECGs recorded with monitoring-compatible lead positions on the torso. Recalibration of ST-segment measurements may be necessary for meticulous quantification of ischemia, infarct size, or other measurements that might be affected by variations < 100 microV.

Constriction↗
PubMed1995

Effect of torso position on arthrometric assessment of anterior knee laxity.

The purpose of the study was to examine the effect of changes in torso position on arthrometric assessment of knee laxity. Anterior tibial translation (ATT) of 12 control and 12 ACL deficient subjects was assessed using a Dynamic Cruciate Tester during five maximal isometric knee extensions and five passive tests (240 N load) on the right and left knee in each of three torso positions: vertical, reclined, and supine. Electromyographic activity of rectus femoris, vastus lateralis, biceps femoris, and semimembranosus were sampled during arthrometric assessment. Results indicated there was no significant difference in mean ATT as a function of torso position. However, subjects demonstrated significantly greater hamstring activity when seated vertically compared to reclined or supine and significantly greater hamstring activity when reclined compared to supine.

Journal Article↗
PubMed2005

Sagittal plane moment arms of the female lumbar region rectus abdominis in an upright neutral torso posture.

BACKGROUND: Prior imaging studies of torso muscle moment arms for use as inputs into biomechanical models have been derived from subjects lying supine. Recent research suggests moment arms of the rectus abdominis are larger when standing versus lying supine. METHODS: Axial MRI images, through and parallel to the intervertebral discs were obtained from five females in a standing upright neutral posture. Digitizing software was utilized to quantify the distance in the sagittal plane between the centroids of the intervertebral disc and the rectus abdominis muscle, and converted to the transverse plane to allow comparisons with studies with subjects in a supine posture. FINDINGS: The mean sagittal plane moment arms in the transverse plane were 9.7, 9.1, 8.5, 8.5 and 9.8 cm at the L(1)/L(2), L(2)/L(3), L(3)/L(4), L(4)/L(5) and L(5)/S(1) intervertebral levels, respectively. Compared with a study on females of a similar age group, the moment arms from this study were larger at each level, increasing from 7.3% larger at L(1)/L(2) to 43.7% larger at L(5)/S(1). INTERPRETATION: Accurate anatomical geometrical representation in biomechanical models is necessary for valid estimates of internal loading. Sagittal plane rectus abdominis moment arms were larger from the upright neutral torso posture in this study compared to studies with subjects lying supine. This suggests the torso internal moment generating capability would be represented differently in biomechanical models that use data from studies where subjects were upright, which is more reflective of the postures biomechanical models are utilized for, than when using anatomical geometry derived from supine postures.

Abdomen↗
PubMed2005

Ras-independent activation of ERK signaling via the torso receptor tyrosine kinase is mediated by Rap1.

In Drosophila embryos, the Torso receptor tyrosine kinase (RTK) activates the small G protein Ras (D-Ras1) and the protein kinase Raf (D-Raf) to activate ERK to direct differentiation of terminal structures . However, genetic studies have demonstrated that Torso, and by extension other RTKs, can activate Raf and ERK independently of Ras . In mammalian cells, the small G protein Rap1 has been proposed to couple RTKs to ERKs. However, the ability of Rap1 to activate ERKs remains controversial, in part because direct genetic evidence supporting this hypothesis is lacking. Here, we present biochemical and genetic evidence that D-Rap1, the Drosophila homolog of Rap1, can activate D-Raf and ERK. We show that D-Rap1 binds D-Raf and activates ERKs in a GTP- and D-Raf-dependent manner. Targeted disruption of D-Rap1 expression decreased both Torso-dependent ERK activation and the ERK-dependent expression of the zygotic genes tailless and huckebein to levels similar to those achieved in D-Ras1 null embryos. Furthermore, combined deficiencies of D-Ras1 and D-Rap1 completely abolished expression of these genes, mimicking the phenotype observed in embryos lacking D-Raf. These studies provide the first direct genetic evidence of Rap1-mediated activation of the MAP kinase cascade in eukaryotic organisms.

Amino Acid Sequence↗
PubMed2005

Computational and experimental models of the human torso for non-penetrating ballistic impact.

Both computational finite element and experimental models of the human torso have been developed for ballistic impact testing. The human torso finite element model (HTFEM), including the thoracic skeletal structure and organs, was created in the finite element code LS-DYNA. The skeletal structure was assumed to be linear-elastic while all internal organs were modeled as viscoelastic. A physical human surrogate torso model (HSTM) was developed using biosimulant materials and the same anthropometry as the HTFEM. The HSTM response to impact was recorded with piezoresistive pressure sensors molded into the heart, liver and stomach and an accelerometer attached to the sternum. For experimentation, the HSTM was outfitted with National Institute of Justice (NIJ) Level I, IIa, II and IIIa soft armor vests. Twenty-six ballistic tests targeting the HSTM heart and liver were conducted with 22 caliber ammunition at a velocity of 329 m/s and 9 mm ammunition at velocities of 332, 358 and 430 m/s. The HSTM pressure response repeatability was found to vary by less than 10% for similar impact conditions. A comparison of the HSTM and HTFEM response showed similar pressure profiles and less than 35% peak pressure difference for organs near the ballistic impact point. Furthermore, the peak sternum accelerations of the HSTM and HTFEM varied by less than 10% for impacts over the sternum. These models provide comparative tools for determining the thoracic response to ballistic impact and could be used to evaluate soft body armor design and efficacy, determine thoracic injury mechanisms and assist with injury prevention.

Biomechanical Phenomena↗
PubMed1976

Part III: the effect of the torso boundaries on the magnetocardiogram.

The magnetic field produced by a current dipole is made up of two parts: the field from the dipole element, and from the current generated by the dipole in the volume conductor. It was previously shown for the semi-infinite volume conductor, infinite slab, and the sphere that the volume-current contribution is zero to the component of magnetic field which is normal to the boundary. The volume conductor in the form of the human torso is here investigated by computer simulation. Three different heart-torso models are used. The contribution to the normal field component (Bn) by the volume current (via the boundaries) and by the heart dipoles are computed. For comparison, the boundary contribution to the surface potential (V) is also computed. For Bn the three models yield a ratio of boundary to dipole contribution in the same range, with 0.28 as the average. Simple subtractions can make this ratio negligible. For V the equivalent ratio is somewhat greater. The arrow map, developed previously to display Bn over special surfaces, is shown to be valid for the human torso, for visually estimating the heart dipoles.

Electromagnetic Phenomena↗
PubMed1994

Terminal pattern elements in Drosophila embryo induced by the torso-like protein.

The genes torso (tor) and torso-like (tsl) are two of the Drosophila maternal group genes implicated in a receptor tyrosine kinase signalling pathway that specifies terminal cell fate (reviewed in ref. 3). Loss-of-function mutations in these loci cause an identical phenotype in which pattern elements from the anterior (acron) and posterior (telson) ends have been deleted. We have cloned the tsl gene and demonstrate here that, in agreement with previous genetic data, it encodes a protein that is secreted and whose transcription is restricted to specialized categories of follicle cells localized at the poles of the egg chamber. At early blastoderm stage, tsl protein forms a symmetrical concentration gradient at the poles on the surface of the devitellinized embryo. Unrestricted expression of the tsl protein in tsl female mutants induces terminal pattern elements and suppresses the formation of abdomen in embryos. These results suggest that the tsl protein is the ligand that binds to the torso receptor.

Amino Acid Sequence↗
PubMed1994

Immediate versus delayed fluid resuscitation for hypotensive patients with penetrating torso injuries.

BACKGROUND: Fluid resuscitation may be detrimental when given before bleeding is controlled in patients with trauma. The purpose of this study was to determine the effects of delaying fluid resuscitation until the time of operative intervention in hypotensive patients with penetrating injuries to the torso. METHODS: We conducted a prospective trial comparing immediate and delayed fluid resuscitation in 598 adults with penetrating torso injuries who presented with a pre-hospital systolic blood pressure of < or = 90 mm Hg. The study setting was a city with a single centralized system of pre-hospital emergency care and a single receiving facility for patients with major trauma. Patients assigned to the immediate-resuscitation group received standard fluid resuscitation before they reached the hospital and in the trauma center, and those assigned to the delayed-resuscitation group received intravenous cannulation but no fluid resuscitation until they reached the operating room. RESULTS: Among the 289 patients who received delayed fluid resuscitation, 203 (70 percent) survived and were discharged from the hospital, as compared with 193 of the 309 patients (62 percent) who received immediate fluid resuscitation (P = 0.04). The mean estimated intraoperative blood loss was similar in the two groups. Among the 238 patients in the delayed-resuscitation group who survived to the postoperative period, 55 (23 percent) had one or more complications (adult respiratory distress syndrome, sepsis syndrome, acute renal failure, coagulopathy, wound infection, and pneumonia), as compared with 69 of the 227 patients (30 percent) in the immediate-resuscitation group (P = 0.08). The duration of hospitalization was shorter in the delayed-resuscitation group. CONCLUSIONS: For hypotensive patients with penetrating torso injuries, delay of aggressive fluid resuscitation until operative intervention improves the outcome.

Abdominal Injuries↗
PubMed2002

A clinical decision rule for identifying children with thoracic injuries after blunt torso trauma.

STUDY OBJECTIVE: We sought to determine the prevalence of thoracic injuries in children sustaining blunt torso trauma and to develop a clinical prediction rule to identify children with these injuries. METHODS: We prospectively enrolled pediatric patients (<16 years) who presented to the emergency department of a Level I trauma center with blunt torso trauma and underwent chest radiography. Clinical findings were recorded in a standardized fashion by the ED faculty physician. Thoracic injuries included the following: pulmonary contusion, hemothorax, pneumothorax, pneumomediastinum, tracheal-bronchial disruption, aortic injury, hemopericardium, pneumopericardium, cardiac contusion, rib fracture, sternal fracture, or any injury to the diaphragm. Multiple logistic regression and recursive partitioning analyses were performed to generate a clinical prediction rule for identifying children with these injuries. RESULTS: Nine hundred eighty-six patients with a mean age of 8.3+/-4.8 years were enrolled. Eighty (8.1%; 95% confidence interval [CI] 6.5% to 10.0%) patients sustained thoracic injuries. Multiple logistic regression and recursive partitioning analyses identified the following predictors of thoracic injuries: low systolic blood pressure (14% with injury versus 2% without injury; adjusted odds ratio [OR] 4.6), elevated age-adjusted respiratory rate (51% versus 16%; adjusted OR 2.9), abnormal results on examination of the thorax (68% versus 36%; adjusted OR 3.6), abnormal chest auscultation findings (14% versus 1%; adjusted OR 8.6), femur fracture (13% versus 5%; adjusted OR 2.2), and a Glasgow Coma Scale (GCS) score of less than 15 (61% versus 26%; adjusted OR 3.3). Seventy-eight (98%; 95% CI 91% to 100%) of the 80 patients with thoracic injuries had at least 1 of these predictive factors. Three hundred thirty-six (37%) children had none of these predictive factors, including 2 (0.6%; 95% CI 0.1% to 2.1%) with thoracic injuries. These 2 injuries, however, did not require any intervention. CONCLUSION: Predictors of thoracic injury in children sustaining blunt torso trauma include low systolic blood pressure, elevated respiratory rate, abnormal results on thoracic examination, abnormal chest auscultation findings, femur fracture, and a GCS score of less than 15. These predictors can be used to create a sensible clinical decision rule for the identification of children with thoracic injuries.

Accidental Falls↗
PubMed2005

Presenting directions with a vibrotactile torso display.

Vibrotactile displays covering the torso present spatial information in an intuitive way since the stimuli are directly mapped to the body coordinates; left is left, front is front, etc. The present study investigated the direction in the horizontal plane to which a specific torso location is mapped using a 15 tactor linear display. Participants indicated the observed external direction of a localized vibration by positioning a remotely controlled cursor. The results show that the observed direction is toward the midsagittal plane (i.e. the navel or the spine) compared to the tactor direction. This bias is consistent over the observers tested, and up to 10 degrees for the oblique directions. Inspection of the response patterns revealed that observers did not use the body midaxis as the origin for the observed direction, but used two spatially separated internal reference points, one for each body half. Therefore, the use of a torso-related transfer function in applications that require a high level of precision is suggested. The variability of the responses also depends on the tactor direction. It is higher for the left - right direction and lower for the fore - aft direction, which may be caused by the spine and navel acting as anchor points. The present results are relevant for tactile navigation displays for visually handicapped individuals or for jet pilots.

Adult↗
PubMed2002

Comparison of Cobb angles measured manually, calculated from 3-D spinal reconstruction, and estimated from torso asymmetry.

While scoliotic spinal deformity is traditionally measured by the Cobb angle, we seek to estimate scoliosis severity from the torso surface without X-ray radiation. Here, we measured the Cobb angle in three ways: by protractor from postero-anterior X-ray, by computer from a 3-D digitized model of the vertebral body line, and by neural-network estimation from indices of torso surface asymmetry. The estimates of the Cobb angle by computer and by neural network were equally accurate in 153 records from 52 patients (standard deviation of 6 degrees from the Cobb angle, r=0.93), showing that torso asymmetry reliably predicted spinal deformity. Further improvements in predictive accuracy may require estimation of other 3-D indices of spinal deformity besides the Cobb angle with its wide measurement variability.

Adolescent↗
PubMed2003

Effect of torso adipose tissue thickness on effective dose in a broad parallel photon beam.

The effect of torso adipose tissue thickness on effective dose was studied for external broad parallel photon beams using the MCNP code and a mathematical anthropomorphic phantom. The variation of torso adipose tissue thickness was modeled by adding a layer of soft tissue (1-7 cm) around the torso of the phantom. This study found that effective dose varies almost linearly with the thickness of the adipose tissue layer. For most irradiation geometries (i.e., antero-posterior, postero-anterior, and lateral), effective dose decreases with the thickness of the adipose tissue layer due to the shielding effect of the layer. Effective dose decreases by 11-35% when the thickness of the adipose tissue layer increases from 0 to 7 cm considering all photon energies (0.08, 0.3, and 1.0 MeV) and irradiation geometries in this study. For overhead irradiation geometry, however, an increase of adipose tissue layer thickness results in an increase of effective dose. This is because the organs and tissues in the body are additionally exposed by the photons that are scattered from the added adipose tissue layer. For the overhead irradiation geometry, effective dose increases by 13-27% when the adipose tissue thickness increases from 0 to 7 cm.

Adipose Tissue↗
PubMed2001

Determining the need for laparotomy in penetrating torso trauma: a prospective study using triple-contrast enhanced abdominopelvic computed tomography.

BACKGROUND: The nontherapeutic laparotomy rate in penetrating abdominal trauma remains high and the morbidity rate in these cases is approximately 40%. Selective management, rather than mandatory laparotomy, has become a popular approach in both stab wounds and gunshot wounds. The advent of spiral technology has stimulated a reassessment of the role of computed tomography (CT) in many aspects of trauma care. We prospectively investigated the current utility of triple-contrast CT as a diagnostic tool to facilitate initial therapeutic management decisions in penetrating torso trauma. METHODS: We studied hemodynamically stable patients with penetrating injury to the torso (abdomen, pelvis, flank, back, or lower chest) without definite indication for laparotomy, admitted to our trauma center during the 1-year period from 7/99 through 6/00. Patients underwent triple-contrast enhanced spiral CT as the initial study. A positive CT scan was defined as any evidence of peritoneal violation (free air or fluid, contrast leak, or visceral injury). Patients with positive CT, except those with isolated solid viscus injury, underwent laparotomy. Patients with negative CT were observed. RESULTS: There were 75 consecutive patients studied: mean age 30 years (range 15-85 years); 67 (89%) male; 41 (55%) gunshot wound, 32 (43%) stab wound, 2 (3%) shotgun wound; mean admission systolic blood pressure 141 mm Hg (range 95-194 mm Hg); 26 (35%) had positive CT and 49 (65%) had negative CT. In patients with positive CT, 18 (69%) had laparotomy: 15 therapeutic, 2 nontherapeutic, and 1 negative. Five patients had isolated hepatic injury and 2 had hepatic and diaphragm injury on CT and all were successfully managed without laparotomy. Of these seven patients, three had angioembolization and two had thoracoscopic diaphragm repair. In patients with negative CT, 47/49 (96%) had successful nonoperative management and 1 had negative laparotomy. The single CT-missed peritoneal violation had a left diaphragm injury at laparotomy. CT accurately predicted whether laparotomy was needed in 71/75 (95%) patients. CONCLUSION: In penetrating torso trauma, triple-contrast abdominopelvic CT can accurately predict need for laparotomy, exclude peritoneal violation, and facilitate nonoperative management of hepatic injury. Adjunctive angiography and investigation for diaphragm injury may be prudent.

Abdominal Injuries↗
PubMed1993

Torso muscle moment arms at intervertebral levels T10 through L5 from CT scans on eleven male and eight female subjects.

Moment arms for eight pairs of torso muscles were estimated based on data obtained from 19 sets of computed tomography (CT) scans. Muscle centroid locations of the rectus abdominis, external oblique, internal oblique, transversus abdominis, latissimus dorsi, psoas, quadratus lumborum, and the erector spinae mass were identified and digitized relative to vertebral body centers, which were also determined from the scans of the eight females and eleven males. Muscle moment arms were then calculated as the distance between the muscle and vertebral body centroids. The centroids for each torso muscle were plotted at each intervertebral level from T10-11 to L4-L5. When these sections were ordered in a cephalocaudad manner, the centroid-line paths, essential to the determination of muscle force lines-of-action, could be traced. Finally, anthropometric variables such as height, weight, torso depth, breadth, and age were regressed against the moment arm group means to develop several prediction equations that would determine moment arm lengths based on these anthropometric variables.

Biomechanical Phenomena↗
PubMed2004

A prospective evaluation of ultrasonography for the diagnosis of penetrating torso injury.

BACKGROUND: Ultrasound (US) is commonly used for the diagnosis of hemoperitoneum after blunt abdominal trauma, but the value of US as an aid for identification of operative lesions after penetrating trauma is not well documented. The purpose of this investigation was to determine the accuracy of US for the evaluation of penetrating torso trauma and to assess the impact of this information on patient management. METHODS: We conducted a prospective cohort observational study of consecutive penetrating torso patients at a Level I trauma center. RESULTS: During the 6-month trial period, 177 victims of penetrating torso trauma were assessed by our trauma teams. Ninety-two patients had stab wounds, 84 patients had gunshot wounds, and 1 patient had a puncture wound. All 28 patients with positive US examination had an exploratory laparotomy or thoracotomy (one patient had more than one procedure), resulting in 26 therapeutic operations. There were 149 negative US examinations, but in this group, 36 patients underwent laparotomy or thoracotomy, and 28 had therapeutic operations. The overall accuracy of the US examination was therefore 85%, the sensitivity was 48%, and the specificity was 98%. There were only three patients who had their initial management altered by a positive US examination. CONCLUSION: The US examination lacks sensitivity to be used alone in determining operative intervention after gunshot or stab wounds. Rarely does US information contribute to the management of patients with penetrating abdominal injuries.

Adolescent↗
PubMed2002

Cell surface proteins Nasrat and Polehole stabilize the Torso-like extracellular determinant in Drosophila oogenesis.

Structural cell-surface and extracellular-matrix proteins modulate intercellular signaling events during development, but how this is achieved remains largely unknown. Here we identify a novel family of Drosophila proteins, Nasrat and Polehole, that coat the oocyte surface and play two roles: They mediate assembly of the eggshell, and act in the Torso RTK signaling pathway that specifies the terminal regions of the embryo. Nasrat and Polehole are essential for extracellular accumulation of Torso-like, a factor secreted during oogenesis that initiates Torso receptor activation. Stabilization of secreted factors by specialized pericellular proteins may be a general mechanism during signaling and developmental patterning.

Animals↗
PubMed1998

MCG simulations with a realistic heart-torso model.

Magnetocardiograms (MCG's) simulated with a high-resolution heart-torso model of an adult subject were compared with measured MCG's acquired from the same individual. An exact match of the measured and simulated MCG's was not found due to the uncertainties in tissue conductivities and cardiac source positions. However, general features of the measured MCG's were reasonably represented by the simulated data for most, but not all of the channels. This suggests that the model accounts for the most important mechanisms underlying the genesis of MCG's and may be useful for cardiac magnetic field modeling under normal and diseased states. MCG's were simulated with a realistic finite-element heart-torso model constructed from segmented magnetic resonance images with 19 different tissue types identified. A finite-element model was developed from the segmented images. The model consists of 2.51 million brick-shaped elements and 2.58 million nodes, and has a voxel resolution of 1.56 x 1.56 x 3 mm. Current distributions inside the torso and the magnetic fields and MCG's at the gradiometer coil locations were computed. MCG's were measured with a Philips twin Dewar first-order gradiometer SQUID-system consisting of 31 channels in one tank and 19 channels in the other.

Adult↗
PubMed1991

Magnetocardiographic functional localization using a current dipole in a realistic torso.

We describe a fast and numerically effective biomagnetic inverse solution using a moving dipole in a realistic homogeneous torso. We applied the localization model and high-resolution magnetocardiographic mapping to localize noninvasively the ventricular preexcitation site in ten patients suffering from Wolff-Parkinson-White syndrome. In all cases, the computed localization results were compared to the results obtained by invasive catheter technique. Using a standard-size torso model in all cases, the average 3-D distance between the computed noninvasive locations and the invasively obtained results was 2.8 +/- 1.4 cm. When the torso was rescaled to better match the true shape of the subject in five cases, the 3-D average was improved to 2.2 +/- 1.0 cm. This accuracy is very satisfactory, suggesting that the method would be clinically useful.

Adult↗