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Three-dimensional osseo-ligamentous model of the thorax representing initiation of scoliosis by asymmetric growth.

A biomechanical model of the human thorax was constructed to investigate how asymmetric growth of the thorax might initiate spinal lateral curvature and axial rotation as seen in scoliosis deformities. Geometric data specifying nodal points of the model were taken from stereo-radiographs of an adolescent subject. An initially symmetrical geometry was created by 'mirroring' measurements of a hemi-thorax and spine. Published data provided cross-sectional measurements of the ribs, material properties of tissues and global flexibilities of the intervertebral motion segments. The ribs, sternum, intervertebral motion segments and intercostal ligaments were represented by elastic elements. Model deformations were calculated by the direct stiffness finite element method, with growth represented by an initial strain term in the constitutive law. Non-linear behavior was accommodated by running the model recursively, with updated node locations at each step. Both stress relaxation and stress modulation of growth in the component tissues were simulated. Thoracic growth of 20% with asymmetric growth of the ribs was simulated to give rib length asymmetries of 11%. similar to that observed in a previous study of patients with idiopathic scoliosis. This resulted in the model having a small thoracic scoliosis curvature convex toward the side of the longer ribs. Variations of the model which permitted free motion at the costo-vertebral joints or produced changes in the curvature of the posterior parts of the ribs resulted in axial rotation of the vertebrae similar to that observed clinically. The model supports the idea that growth asymmetry could initiate a small scoliosis during adolescence.

Adolescent↗

Influence of thorax irradiation on the survival of mice with spontaneous or artificial lung metastases from a transplantable mammary adenocarcinoma.

The effect of thorax irradiation on lung metastases, either occurring spontaneously from a primary mammary adenocarcinoma (M8013X) transplanted on the leg or artificially induced by intravenous injection of tumor cells was studied. Increasing the interval between the moment at which lung metastases are supposed to originate and the thorax irradiation resulted in a rapid decrease of the effectiveness of this treatment in preventing the development of lung metastases. Early treatment of the mice not only resulted in a considerable number of animals that were cured, but also in a significant decrease in the number of tumor localizations in the lung of those animals still developing metastases. Thorax irradiation performed later was much less effective; at autopsy the lung showed a large number of small metastases. Increasing the radiation dose led to an increased number of cures; however, an increased number of mice dying of lethal lung damage was also observed. Irradiation of the lungs of mice with 5 or 10 Gy, 24 hours, 7 days or 14 days prior to i.v. injection with tumor cells, did not significantly increase the number of mice with lung metastases. Immunological resistance against the tumor played a role in our experiments with both spontaneous and artificial lung metastases.

Adenocarcinoma↗

Magnetic resonance imaging of the thorax. Past, present, and future.

Magnetic resonance imaging is a valuable modality of extreme flexibility for specific problem-solving capability in the thorax. This article reviews MR applications in the imaging of great vessels, which are currently the most important applications in the thorax; other established applications in the thorax; and pulmonary functional MR imaging.

Humans↗

A misexpression study examining dorsal thorax formation in Drosophila melanogaster.

We studied thorax formation in Drosophila melanogaster using a misexpression screen with EP lines and thoracic Gal4 drivers that provide a genetically sensitized background. We identified 191 interacting lines showing alterations of thoracic bristles (number and/or location), thorax and scutellum malformations, lethality, or suppression of the thoracic phenotype used in the screen. We analyzed these lines and showed that known genes with different functional roles (selector, prepattern, proneural, cell cycle regulation, lineage restriction, signaling pathways, transcriptional control, and chromatin organization) are among the modifier lines. A few lines have previously been identified in thorax formation, but others, such as chromatin-remodeling complex genes, are novel. However, most of the interacting loci are uncharacterized, providing a wealth of new genetic data. We also describe one such novel line, poco pelo (ppo), where both misexpression and loss-of-function phenotypes are similar: loss of bristles and scutellum malformation.

Animals↗

Source and direction of thoracic lymphatics: Part I--upper thorax.

The purpose of this set of two articles is to illustrate the source and direction of lymphatic drainage in the thorax on axial CT schematics. The first article describes the upper thorax. The second article will describe the lower thorax. The nodal groups are given conventional anatomic names and the corresponding terminology of the American Thoracic Society. Arrows indicate the direction of the flow. The region or organ drained is color-coded, and nodes that receive lymph from each area are assigned appropriately colored boxes. Major drainage patterns are also described. This information can be used to assess a suggestive lymph node by tracing it to the region of drainage and looking for pathological lesions. Alternatively, one may extrapolate the potential drainage routes of a tumor and scrutinize specific sites for nodal metastases.

Fluorodeoxyglucose F18↗

The source and direction of thoracic lymphatics, part II: The lower thorax.

The purpose of this set of 2 articles is to illustrate the source and direction of lymphatic drainage in the thorax on axial computed tomographic (CT) schematics. The first article describes the upper thorax. This article describes the lower thorax. The nodal groups are given conventional anatomic names and the corresponding terminology of the American Thoracic Society. Arrows indicate the direction of the flow. The region or organ drained is color-coded, and nodes that receive lymph from each area are assigned appropriately colored and numbered boxes. Major drainage patterns are also described. This information can be used to assess a suspicious lymph node by tracing it to the region of drainage and looking for pathology. Alternately, one may extrapolate the potential drainage routes of a tumor and scrutinize specific sites for nodal metastases.

Humans↗

Gas flow distribution in distal high frequency jet ventilation and lung thorax compliance.

To investigate the influence of changes in thorax and lung compliance on ventilation during distal High Frequency Jet Ventilation (HFJV), similar ventilator settings were compared before and after changing the compliance in two groups of anaesthetized mongrel dogs. Each period of distal HFJV was preceded by adequate Intermittent Positive Pressure Ventilation (IPPV) to assure a start with baseline values. In Group 1 (n = 7), thorax compliance was changed by chest strapping, while in Group 2 (n = 7) lung compliance was changed by inducing acute lung injury by injection of oleic acid into the right atrium. Gas flow distribution in the ventilatory circuit during distal HFJV was determined before and after the changes in compliance were induced. Comparing similar ventilator settings during distal HFJV in the same dog, a decrease in lung or thorax compliance led to changes in gas flow distribution in the ventilatory circuit. Entrainment was decreased and bypass increased with a negative effect on the gas volume entering the lungs and on gas exchange. The results indicate that distal HFJV should be regarded as pressure-limited ventilation.

Animals↗

Intercostal muscles are used during rotation of the thorax in humans.

To test the idea that the lateral intercostal muscles may be more suited to aid in rotational than respiratory movements of the thorax, we inserted bipolar fine-wire electrodes in external and internal intercostal muscles in the right midaxillary line in nine sitting subjects and examined the pattern of contraction of these muscles during voluntary axial rotations of the thorax (30-35 degrees), resting breathing, and CO2-induced hyperpnea. The right external intercostal muscles were strongly recruited in rotations to the left but were not active in rotations to the right. In contrast, the right internal intercostal muscles were active in rotations to the right but not in rotations to the left. Rotations completed in 1 or 2 s were associated with an early burst of electromyographic activity, followed by a low plateau that persisted while the rotation was held. Rotations made very gradually over 5-10 s were associated with gradually rising electromyographic activity. The amplitude of activity recorded during 30-35 degrees rotations was equivalent to that measured when minute ventilation was increased by CO2 to 50 l/min. We conclude that the lateral intercostal muscles have a major role in producing axial rotations of the thorax.

Adult↗

Regulation of the spalt/spalt-related gene complex and its function during sensory organ development in the Drosophila thorax.

The nuclear proteins Spalt and Spalt-related belong to a conserved family of transcriptional regulators characterised by the presence of double zinc-finger domains. In the wing, they are regulated by the secreted protein Decapentaplegic and participate in the positioning of the wing veins. Here, we identify regulatory regions in the spalt/spalt-related gene complex that direct expression in the wing disc. The regulatory sequences are organised in independent modules, each of them responsible for expression in particular domains of the wing imaginal disc. In the thorax, spalt and spalt-related are expressed in a restricted domain that includes most proneural clusters of the developing sensory organs in the notum, and are regulated by the signalling molecules Wingless, Decapentaplegic and Hedgehog. We find that spalt/spalt-related participate in the development of sensory organs in the thorax, mainly in the positioning of specific proneural clusters. Later, the expression of at least spalt is eliminated from the sensory organ precursor cells and this is a requisite for the differentiation of these cells. We postulate that spalt and spalt-related belong to a category of transcriptional regulators that subdivide the thorax into expression domains (prepattern) required for the localised activation of proneural genes.

Animals↗

Clinical estimation of left ventricular size: precordial electrocardiographic voltage corrected by the measurement of thorax.

The left ventricular muscle volume (LVMV) was determined echocardiographically and the radius of the circle with equal circumference to the thorax (R1) was calculated from thorax-circumference in 688 children as a part of the Shimane Heart Study. correlation of the summed precordial voltage (SV1 + RV5) with LVMV was not close (r = 0.377 in boys and -0.095 in girls). The precordial voltage (SV1 + RV5) was corrected by the square of R1 to compensate for the diminution of electrical potential by distance. Correlation between (R1) 2 x (SV1 + RV5) and LVMV was good in boys (r = 0.681) and relatively good in girls (r= 0.554). This fact indicates that LVMV can be predicted from ECG and anthropometric measurements of thorax without using echocardiography. Therefore, (R1) 2 x (SV1 + RV5) seems to have clinical applicability as the index of LV size, if the differences in (R1) 2 x (SV1 + RV5) and in the correlation coefficient between both sexes are clarified further.

Adolescent↗

The causative mechanisms of mitral valve prolapse in progressive muscular dystrophy in reference to thorax and thoracic spine deformities and left ventricular dysfunction.

The causative mechanisms of mitral valve prolapse (MVP) were evaluated in 58 patients with progressive muscular dystrophy (PMD). Two possible causes, 1) left ventricular (LV) dysfunction and 2) thoracic spine and thorax deformities were assessed. Patients were classified into three groups by echocardiographic findings. Group 1: 31 patients without MVP, group 2: 11 patients with MVP confirmed only by M-mode echocardiogram, group 3: 16 patients with MVP confirmed by both two-dimensional and M-mode echocardiograms. LV functions evaluated by systolic time intervals and fractional shortening showed no significant differences among the three groups. Scoliosis of the thoracic spine was not related to the incidence of MVP. Lordotic or straight spines were found in 32.3%, 100%, 93.8% of cases in group 1, group 2 and group 3, respectively, and the incidences of MVP in cases with kyphosis, straight spine and lordosis were 4.8%, 66.7% and 77.8%, respectively. The shape of the thorax as evaluated by the ratio of anteroposterior internal diameter to transverse diameter was more flattened in groups 2 and 3 than in group 1. From these results, we concluded that LV dysfunction was not related to the incidence of MVP and that the lordotic or straight spine and the flattened thorax were supposed to be the major factors in the occurrence of MVP in PMD.

Adolescent↗

[Effects of human thorax tissues on conduction of electrocardiogram and body surface potential].

In this paper, the forward problem of electrocardiogram(ECG) has been calculated by means of numerical simulating techniques. Firstly, It is focused on the effects of organs and tissues within the thorax on the body surface potentials under a 2-D cross section of thorax in terms of finite element method (FEM). To check the effect of skeletal muscle layers on ECG, the simulating computation of ECG, by a method combining FEM with boundary element method (BEM), has been carried out in terms of a 3-D thorax model.

Algorithms↗

Cutaneous innervation of the thorax and abdomen of the dog.

The anatomy of the cutaneous nerves innervating the canine thorax and abdomen was investigated by gross dissection of 38 dogs. Additionally, the cutaneous areas innervated by the thoracic and abdominal cutaneous nerves were mapped in a 2nd group of 33 barbiturate-anesthetized male dogs, using electrophysiologic techniques. The skin of the thorax was innervated by dorsal cutaneous branches, lateral cutaneous branches, and ventral cutaneous branches of the spinal nerves. The dorsal cutaneous branches were branches of the dorsal primary branches of spinal nerves C6 and T2 through T11. The lateral cutaneous branches were branches of the ventral primary branches of spinal nerves T2 through T12. The ventral cutaneous branches were branches of the ventral primary branches of spinal nerves T2 through T10. The skin of the abdomen was innervated by dorsal and lateral cutaneous branches of spinal nerves T12 through L3 (and occasionally L4). The cutaneous areas of the dorsal cutaneous branches occupied the dorsal half of the scapular and thoracic regions and the dorsal 2/5 of the abdominal region. The cutaneous areas of the lateral cutaneous branches covered the major portion of the ventral half of the thorax and the ventral 3/5 of the abdomen. The cutaneous areas of the ventral cutaneous branches occupied the axilla and the ventral part of the thoracic wall.

Abdomen↗

[Effectiveness of selection for thorax length in model Drosophila populations in chemical mutagen exposure].

Artificial selection for increasing and decreasing Drosophila thorax length was carried out over 20 generations. Chemical mutagen, dimethylsulfate (DMS) was regularly applied to enhance genetic variation in selected lines. It was determined that under the influence of mutagen the efficiency of selection for decreasing thorax length was much higher, while selection course for increasing thorax length was not affected significantly. Regression coefficient of responses to selection, general for males and females, was equal to b = -0.035 +/- 0.004 for lines of negative direction of selection when the mutagen was applied and -b = -0.023 +/- 0.004 without mutagenesis; for lines of positive direction b = 0.026 +/- 0.005 and b = 0.024 +/- 0.005. Fitness component variation by artificial selection was studied. A complex correlation was detected between direction of selection, the shift value of model quantitative character and fitness component variation by selection. The main factor stimulating a sharp drop of average fitness of lines appeared to be the influence of directional artificial selection. The regular treatment by a moderate dose of the mutagen did not affect markedly the average fitness variation of selected lines.

Animals↗

[Perimeters of the arm and the thorax as indicators of low birth weight].

In a group of 317 newborns, measurements of the perimeter of the arm and the thorax were taken as an indicator of low birth weight. The perimeters of both the arm and the thorax had a high correlation with low birth weight (LBW) (0.88-0.80 respectively). In the sample group, the cut-off point to define low birth weight in the case of perimeter of the arm was 9 cm and was 29-30 cm for perimeter of the thorax. Applying these measurements facilitates early detection and treatment of low birth weight babies who are at risk for infant mortality in situations where it is not possible to weigh the baby at birth.

Arm↗

High energy (42-66 MeV reactions) fast neutron dose optimization studies in the head and neck, thorax, upper abdomen, pelvis and extremities.

Five hundred and fifty patients were entered into a set of dose-searching studies designed to determine normal tissue tolerance to high energy (42-66 MeV reactions) fast neutrons delivered in 12 equal fractions over 4 weeks. Participating institutions included: The Fermilab (66 MeV p+----Be), The University of Washington (50 MeVp+----Be), U.C.L.A. (45 MeVH-----Be), M.D. Anderson Hospital (42 MeVH-----Be), and The Cleveland Clinic (42 MeVp+----Be). Patients were stratified by treatment facility and then randomized to receive 16, 18 or 20 Gy for tumors located in the upper abdomen or pelvis, and 18, 20 or 22 Gy for tumors located in the head and neck, thorax or extremities. Following completion of the randomized protocols, additional patients were studied at the 20.4 Gy level in the head and neck, thorax and pelvis. Normal tissue effect scoring was accomplished using the RTOG-EORTC acute and late normal tissue effect scales. Acute Grade 3 + toxicity rates in the head and neck were 19% for 20/20.4 Gy and 20% for 22 Gy. Time adjusted late toxicity rates in the head and neck at 12 months were 15% for 20/20.4 Gy and 0% for 22 Gy. The 18 Gy treatment arm of the head and neck protocol was dropped early in the study after only two patients were accrued. For cases treated in the thorax, acute Grade 3 + toxicity rates were 6% for 18 Gy, 15% for 20/20.4 Gy and 7% for 22 Gy. Late toxicity rates at 12 months were 0% for 18 Gy, 11% for 20/20.4 Gy and 18% for 22 Gy. Acute Grade 3+ toxicity rates in the upper abdomen were 0% for 16 Gy, 8% for 18 Gy and 12% for 20 Gy. There were no Grade 3 + late toxicities in the upper abdomen. In the pelvis, acute Grade 3 + toxicity rates were 0% for 16 Gy, 3% for 18 Gy and 3% for 20/20.4 Gy. Late Grade 3 + toxicities at 24 months were 20% for 16 Gy, 5% for 18 Gy and 24% for 20/20.4 Gy. In extremities, acute Grade 3 + toxicity rates were 7% for 20 Gy and 21% for 22 Gy while at 12 months, late Grade 3 + toxicity rates were 14 and 35%, respectively. The 18 Gy treatment arm of the extremities protocol was dropped early in the study after only two patients were accrued. Factors associated with normal tissue effects in addition to treatment dose are discussed.

Abdominal Neoplasms↗

Neurogenic tumors of the thorax.

Neurogenic tumors of the thorax are observed in all age groups, although they are rare in the elderly. They are more likely to be malignant in the child than in the adult. Tumors of the autonomic system are common in children, whereas the nerve sheath tumors are more likely to be found in adults. The malignant lesions are almost always symptomatic and the benign lesions asymptomatic, except in the child, in whom a benign lesion may result in symptoms because of its size relative to the volume of the child's thorax. Intraspinal canal extension, although relatively infrequent, should be sought for in all paravertebral tumors, for a significant percentage of these may be initially asymptomatic. Excision of such an hourglass tumor without foreknowledge of such extension may lead to serious spinal cord complications. Surgical excision of most of these tumors is sufficient except for the malignant lesions, especially in infancy and childhood, for which the addition of postoperative irradiation and chemotherapy may be beneficial. The prognosis after the removal of benign neurogenic tumors of the thorax is excellent. In the infant or child with Stage III or IV neuroblastoma, ganglioneuroblastoma, or an Askin tumor, the prognosis is poor. In the adult with a malignant neurogenic sarcoma or a malignant paraganglioma, the prognosis likewise is grave.

Autonomic Nervous System Diseases↗

Magnetic resonance imaging of the thorax. Past, present, and future.

Magnetic resonance is a valuable modality of extreme flexibility for specific problem-solving capability in the thorax. This article reviews MR applications in the imaging of great vessels, which are currently the most important applications in the thorax; other established applications in the thorax; and pulmonary functional MR imaging.

Aortic Diseases↗