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Interactions of Eph-related receptors and ligands confer rostrocaudal pattern to trunk neural crest migration.

BACKGROUND: In the trunk of avian embryos, neural crest migration through the somites is segmental, with neural crest cells entering the rostral half of each somitic sclerotome but avoiding the caudal half. Little is known about the molecular nature of the cues-intrinsic to the somites-that are responsible for this segmental migration of neural crest cells. RESULTS: We demonstrate that Eph-related receptor tyrosine kinases and their ligands are essential for the segmental migration of avian trunk neural crest cells through the somites. EphB3 localizes to the rostral half-sclerotome, including the neural crest, and the ligand ephrin-B1 has a complementary pattern of expression in the caudal half-sclerotome. To test the functional significance of this striking asymmetry, soluble ligand ephrin-B1 was added to interfere with receptor function in either whole trunk explants or neural crest cells cultured on alternating stripes of ephrin-B1 versus fibronection. Neural crest cells in vitro avoided migrating on lanes of immobilized ephrin-B1; the addition of soluble ephrin-B1 blocked this inhibition. Similarly, in whole trunk explants, the metameric pattern of neural crest migration was disrupted by addition of soluble ephrin-B1, allowing entry of neural crest cells into caudal portions of the sclerotome. CONCLUSIONS: Both in vivo and in vitro, the addition of soluble ephrin-B1 results in a loss of the metameric migratory pattern and a disorganization of neural crest cell movement. These results demonstrate that Eph-family receptor tyrosine kinases and their transmembrane ligands are involved in interactions between neural crest and sclerotomal cells, mediating an inhibitory activity necessary to constrain neural precursors to specific territories in the developing nervous system.

Animals↗

Effects of subthalamic nucleus stimulation and L-dopa in trunk kinematics of patients with Parkinson's disease.

In the advanced phase of Parkinson's disease (PD), high frequency electrical stimulation (HFS) of the subthalamic nucleus (STN) can represent a good therapeutic option, whose effects on walking have been recently quantified by kinematic and dynamic gait analysis. The goal of the present study was to compare, in a group of PD patients, the effects of STN stimulation and of L-dopa on trunk kinematics during walking. The additive effect of these two treatments was investigated as well. Ten idiopathic PD patients implanted bilaterally with a STN stimulation system and ten age-matched controls were studied using a three dimensional motion analyser. Four conditions were considered: with (s+) and without (s-) STN stimulation and with (m+) and without (m-) L-dopa administration. The results showed that both stimulation alone and L-dopa alone significantly increased the stride length and the gait speed, with an additional effect if applied simultaneously. Cadence was more influenced by L-dopa. The range of lateral bending and torsion of the trunk, which were reduced in s-/m-, increased similarly in s-/m+ and in s+/m- conditions. The exaggerated forward inclination of the trunk reduced towards control values in all therapeutic conditions. There was a tendency for L-dopa to increase trunk movements in the frontal plane, similar to events seen in quiet stance. Due to the presence of additive and synergistic effects, we concluded that the mechanisms of action of the two treatments are likely to be different.

Aged↗

Sitting balance I: trunk-arm coordination and the contribution of the lower limbs during self-paced reaching in sitting.

The effects of reach distance and type of task on the functional relationship between the trunk, upper limb segments and the lower limbs during self-paced reaching in sitting were examined. Two-dimensional kinematic, kinetic and electromyography (EMG) data were collected as six healthy subjects reached forward under three distance (60, 100, 140% arm's length) and two task (reaching to press a switch, reaching to grasp a glass) conditions. The results demonstrate that type of task affected primarily the temporal aspects of coordination, with the grasp task taking consistently longer than the press task. In contrast, reach distance affected both the spatio-temporal aspects of coordination between the trunk and arm segments and the active contribution of the lower limbs. As reach distance increased, the magnitude of trunk and upper-arm segmental motion increased, whereas forearm segmental motion decreased. However, at each reach distance the path of the hand was relatively straight and there was remarkable consistency in the relationship between trunk and arm segments both within and between subjects suggesting that despite the presence of redundant degrees of freedom, the individual uses a parsimonious coordinative pattern. The vertical ground reaction force (GRF) and EMG data demonstrated that the lower limbs actively contributed to support the body mass when the object was located at 140% arm's length.

Adult↗

Clinical analysis of pericardial devascularization by preserving vagus trunks in 42 patients with portal hypertension.

Pericardial devascularization (PD) is less of a burden and provides better bleeding control to patients compared to shunt procedures, and so has been widely used in portal hypertension in China. However, because the vagus trunks are interrupted during surgery, patients easily suffer from postoperative stomach adynamia. Based on our understanding from autopsy of the path of vagus trunks along the distal oesophagus, we designed the operative procedure of PD by preserving vagus trunks (PDPVT) to treat portal hypertension. Between May 1991 and January 2003, patients with portal hypertension were treated surgically using PDPVT (n = 42), single PD (n = 32), or PD with pyloroplasty (PD+PP; n = 16). Operative mortality was 2.4% in the PDPVT group and 6.3% in both the PD and PD+PP groups (p > 0.05). The postoperative rebleeding rate was 9.5% in the PDPVT group and 12.5% in both the PD and PD+PP groups (p > 0.05). There were no differences in operative time and estimated blood loss between the three groups (p > 0.05). The recovery time for gastroenteric function was shorter with PDPVT (mean, 3.5 days) than with PD (mean, 5.7 days) and PD+PP (mean, 4.2 days; p < 0.02). Incidences of early satiety and enterogastric reflux were significantly lower in the PDPVT group (both 4.8%) than in the PD group (46.9% and 18.8%) and PD+PP group (12.5% and 100%; p < 0.005). Incidences of retention of gastric juice, diarrhoea and late gallstones were 12.5%, 15.6% and 7.1%, respectively, in the PD group, and 12.5%, 18.8% and 6.3%, respectively, in the PD+PP group, but none of these were observed in the PDPVT group. Since it preserves vagus trunks, PDPVT can maintain normal stomach dynamics and physiological function of hepatobiliary and gut systems better than PD and PD+PP, thus reducing incidences of postoperative complications. Thus, PDPVT is superior to PD and PD+PP in the treatment of portal hypertension.

Adolescent↗

Integrin antagonists affect growth and pathfinding of ventral motor nerves in the trunk of embryonic zebrafish.

Integrins are thought to be important receptors for extracellular matrix (ECM) components on growing axons. Ventral motor axons in the trunk of embryonic zebrafish grow in a midsegmental pathway through an environment rich in ECM components. To test the role of integrins in this process, integrin antagonists (the disintegrin echistatin in native and recombinant form, as well as the Arg-Gly-Asp-Ser peptide) were injected into embryos just prior to axon outgrowth at 14-16 h postfertilization (hpf). All integrin antagonists affected growth of ventral motor nerves in a similar way and native echistatin was most effective. At 24 hpf, when only the three primary motor axons per trunk hemisegment had grown out, 80% (16 of 20) of the embryos analyzed had abnormal motor nerves after injection of native echistatin, corresponding to 19% (91 of 480) of all nerves. At 33 hpf, when secondary motor axons were present in the pathway, 100% of the embryos were affected (24 of 24), with 20% of all nerves analyzed (196 of 960) being abnormal. Phenotypes comprised abnormal branching (64% of all abnormal nerves) and truncations (36% of all abnormal nerves) of ventral motor nerves at 24 hpf and mostly branching of the nerves at 33 hpf (94% of all abnormal nerves). Caudal branches were at least twice as frequent as rostral branches. Surrounding trunk tissue and a number of other axon fascicles were apparently not affected by the injections. Thus integrin function contributes to both growth and pathfinding of axons in ventral motor nerves in the trunk of zebrafish in vivo.

Animals↗

The comparison of trunk muscles EMG activation between subjects with and without chronic low back pain during flexion-extension and lateral bending tasks.

The purpose of the study was to compare the electromyographic (EMG) activity of the trunk muscles between normal subjects and chronic low back pain (CLBP) patients during standardized trunk movements. Thirty-three male subjects (18 normals, 15 suffering from non specific CLBP) aged between 35 and 45 yr participated. A biomechanical analysis involving the recording of EMG signals from 12 trunk muscles, the kinematics of trunk segments and the computation of L5/S1 moments was performed. The subjects performed flexion-extension and lateral bending (left and right) tasks (three complete cycles) with and without a 12 kg load. Between group comparisons were performed on the full cycle average pattern of all biomechanical variables for each task. The reliability of EMG variables was evaluated for 10 subjects (5 normals and 5 CLBP) who performed the tasks on three different days. The reliability of EMG amplitude values was generally excellent for agonist muscles but poor to moderate for antagonists. The EMG amplitude analysis revealed significant differences between groups for some muscles (left lumbar and thoracic erector spinae). The abnormal (asymmetric) EMG patterns detected among CLBP patients were not explained by postural asymmetries.

Adult↗

Biochemical responses of Pinus pinaster trees to fire-induced trunk girdling and crown scorch: secondary metabolites and pigments as needle chemical indicators.

The biochemical responses to varying levels of localized heat damage to stems and crowns were studied in Pinus pinaster trees in Galicia, Spain. The objective was to ascertain the utility of secondary metabolites (total polyphenols. condensed tannins, astringency, free and esterified phenolic acids) and pigments (chlorophylls and carotenoids) as chemical indicators of localized fire damage. The study involved three levels of girdling by trunk heating (0%, 60%, and 75%), three levels of crown scorching (0%, 50%, and 75%), and all combinations of those trunk and crown treatment levels. Secondary metabolites and pigments were analyzed in needles before, during, and up to 8 months after fire treatments. High levels of polyphenols, condensed tannin, and pigments occurred in situations where the sole treatment was 75% crown scorching. Low levels of hydroxycinnamic acids were the result when the treatment was 75% trunk girdling. These responses occurred in the first two months after fire. Thereafter, normal values were observed. Low values of chlorophyll a/b ratio and high levels of free protocatechuic and esterified syringic acids were found to be long-term indicators of trunk girdling damage combined with crown scorching.

Analysis of Variance↗

Isoresistive dynamometer measurement of trunk muscle velocity at different angular phases of flexion and extension.

Isoresistive trunk muscle dynamometer is a potentially useful piece of equipment in evaluation of trunk muscle velocity, but to date, studies analysing the possibilities and limitations of such measurements are scarce. The aim of this study was to analyse the trunk muscle velocity in repetitive flexion and extension movements at three different angular phases, using an isoresistive trunk muscle dynamometer, and to assess the reliability of the measurements. The study population consisted of 120 healthy, sedentary men and women who volunteered for the study. The measurements were carried out before and after a 22-week training intervention programme. The results show that the peak velocities of the phases between 15 and 35 degrees in flexion and 20-0 degrees in extension (i.e. the second phases) correlated highly (r=0.99 in flexion and in extension) with the peak velocity of the whole movement ranging from -5 to 55 degrees in flexion and 40 to -20 degrees in extension. Correlations were high, both before and after the intervention. The LISREL model analysis showed high reliability of measurement for the second angular phases (in flexion and extension). According to the model, the correlation between the first and second measurement (with a 22-week training intervention in between) was 0.78 in flexion and 0.81 in extension. In conclusion, the angular phases from 15 to 35 degrees in flexion and from 20 to 0 degrees in extension represent the peak velocity of the whole movement. Negative residual correlations between the first and last angular phases in the LISREL model reflect the way of performing the movement: the faster the start the slower the end, and vice versa.

Adult↗

Socio-economic and dietary influences on leg length and trunk length in childhood: a reanalysis of the Carnegie (Boyd Orr) survey of diet and health in prewar Britain (1937-39).

Social class differences in height have been recognised for many centuries. However, few studies have examined the extent to which these differences are made up of differences in leg length or trunk length. This paper reanalyses cross-sectional information on children examined in Britain in the 1930s. We assess associations between socio-economic status and diet and the components of childhood stature. The analyses were based on the records of 2990 children aged 2 years to 14 years 9 months who were examined in the Carnegie (Boyd Orr) survey of diet and health (1937-39). z-Scores for the measures of childhood stature were calculated using polynomial regression techniques with the study population as the standard. Univariable and multivariable statistical techniques were used to assess the relationships between childhood height, leg length and trunk length, and dietary and socio-economic factors measured at the level of the household. Leg length was the component of stature most strongly associated with measures of childhood diet and socio-economic status. A greater part of the difference in stature between socio-economic groups was caused by differences in leg length rather than trunk length. In multiple regression analyses, district of residence and family food expenditure were generally the two factors most strongly related to stature. In a subsample of the surveyed children, for whom birthweight information was available, trunk length and leg length were equally strongly related to birthweight. Leg length appears to be a particularly sensitive indicator of childhood socio-economic circumstances. Although contemporary studies highlight the importance of biological factors in determining childhood height, the data analysed in this study suggest that socio-economic circumstances were also important in explaining height differentials in prewar Britain.

Adolescent↗

Surface landmarks of the facial nerve trunk: a prospective measurement study.

BACKGROUND: Facial nerve identification and preservation is the key to safe parotidectomy in most clinical situations. Traditional approaches to the main trunk have depended solely on internal landmarks but localization may further be enhanced if data are available on its position with reference to neighbouring external features. METHODS: Prospective measurements were taken on a series of parotidectomy patients intraoperatively. Using that spot on the main trunk 10 mm proximal to its bifurcation as the reference point, the depth from the skin and its cranio-caudal distance from the summit of the tragus were measured. RESULTS: Thirty-three patients were included, whose body mass index showed that they had average body build. The reference point nerve was 23.6 mm (SD = 5.1 mm) from the skin surface, and 18.8 mm (SD = 6.0 mm) caudal to the tragus. CONCLUSION: Measurements relating to the siting of the facial nerve trunk were obtained live at operation. This information should be helpful in the initial mobilization of the parotid gland from its posterior relations and in facilitating the classical internal landmarks in the 3-D localization of the main trunk, thereby allowing quicker and safer parotidectomy.

Adult↗

Appearance of right bundle branch block in electrocardiograms of patients with pulmonary embolism as a marker for obstruction of the main pulmonary trunk.

A number of changes occur in the electrocardiogram (ECG) of pulmonary embolism. This article deals with the diagnostic value of the newly emerged right bundle branch block (RBBB) as a manifestation of acute right ventricular overload. A certain correlation between the extent of obstruction of the pulmonary artery and the appearance of RBBB is established through dynamic monitoring of the ECG. Fifty cases of dissectionally proven pulmonary embolism are observed, in 20 of which massive trunk obstruction had taken place, and in the remaining 30 peripheral embolism in the pulmonary artery was established. With 80% of the trunk embolism patients (16 cases), a newly emerged RBBB was detected in their ECG, and with the remaining 20% (4 cases), ST-segment depression and T-wave inversion in leads V(1)-V(4) were observed as well as right axis deviation. S(1)Q(3)T(3) syndrome was detected among 60% (12 cases) of trunk embolism patients. In none of the peripheral embolism cases was RBBB in the ECG registered. Thus, its appearance on dynamic monitoring of the ECG of pulmonary embolism patients is a significant sign of the probability of massive obstruction of the main pulmonary trunk.

Bundle-Branch Block↗

Nerve trunk pain: physical diagnosis and treatment.

The management of peripheral neuropathic pain or nerve trunk pain relies upon accurate differential diagnosis. In part neurogenic pain has been attributed to increased activity in, as well as to abnormal processing of non-nociceptive input from, the nervi nervorum. For neurogenic pain to be identified as the dominant feature of a painful condition there should be evidence of increased nerve trunk mechanosensitivity from all aspects of the physical examination procedure. Consistent dysfunction should be identified on key active and passive movements, neural tissue provocation tests as well as nerve trunk palpation. A local cause for the neurogenic pain disorder should also be identified if the condition is to be treated by manual therapy. A treatment approach is presented which has been shown to have efficacy in the relief of pain and restoration of function in cervicobrachial pain disorders where there is evidence according to the outlined examination protocol of nerve trunk pain.

Brachial Plexus Neuritis↗

[Function of the trunk musculature in elite rowers].

In sports medicine, disorders of muscle function and muscular imbalance play an important role in both risk of injury and lack of improvement. They are highly important for the trunk muscle function, since low back pain is one of the most common disorders of sportsmen and is usually diagnosed as "functional disorder" without further specification. Despite its relevance, little is known about the specific capabilities of trunk muscle function in elite sportsmen. This study describes the measurement of trunk muscle torque, velocity, endurance and coordination in elite sportsmen. The study was performed by clinical examination and an isoinertial testing device (ISOSTATION-B200, Isotechnologies, Hillsborough, NC, USA). The results of a study of 20 German elite male rowers are presented and the relevance of these results is discussed in respect of their implications for training and therapy in injured athletes. Mean torques in extension and flexion were 319 Nm and 295 Nm, respectively. Elite rowers were stronger in isometric torque in all planes compared to normals and other sports groups, such as tennis players and swimmers. The better the rowing performance was, the lower was the extension/flexion ratio, the coordination and the decrease in velocity during endurance testing. This testing procedure is a useful tool in the measurement of trunk performance in elite sportsmen.

Adult↗

Reversible pulmonary trunk banding. II. An experimental model for rapid pulmonary ventricular hypertrophy.

OBJECTIVE: An experimental model with a reversible pulmonary trunk banding device was developed with the aim of inducing rapid ventricular hypertrophy. The device consists of an insufflatable cuff connected to a self-sealing button. METHODS: The right ventricles of 7 young goats (average weight, 8.7 kg) were submitted to systolic overload and evaluated according to the hemodynamic, echocardiographic, and morphologic aspects. Baseline biopsy specimens were taken from the myocardium for microscopic analysis. The device was implanted on the pulmonary trunk and inflated so that a 0.7 right ventricular/left ventricular pressure ratio was achieved. Echocardiographic and hemodynamic evaluations were performed every 24 hours. Systolic overload was maintained for 96 hours. The animals were then killed for morphologic study. Another 9 goats (average weight, 7.7 kg) were used for control right ventricular weight. RESULTS: The systolic right ventricular/pulmonary trunk pressure gradient varied from 10.1 +/- 4.3 mm Hg (baseline) to 60.0 +/- 11.0 mm Hg (final). Consequently, the right ventricular/left ventricular pressure ratio increased from 0.29 +/- 0.06 to 1.04 +/- 0.14. The protocol group showed a 74% increase in right ventricular mass when compared with the control group. Serial 2-dimensional echocardiography showed a 66% increase in right ventricular wall thickness. There was a 24% increase in the mean myocyte perimeter, and the myocyte area increased 61%. CONCLUSIONS: The device is easily adjustable percutaneously, enabling right ventricular hypertrophy in 96 hours of gradual systolic overload. This study suggests that the adjustable pulmonary trunk banding might provide better results for the 2-stage Jatene operation and for the failed atrial switch operations to convert to the double-switch operation.

Animals↗

Trunk asymmetry and facial symmetry in young adults.

The aim of the present study was to detect possible associations between trunk and cervical asymmetry and facial symmetry. Frontal cephalograms prepared in the natural head position, representing 79 subjects (40 males, 39 females) with mild to moderate trunk asymmetry, were analyzed separately for thoracic humps, lumbar prominences, and cervical inclination by discriminating two groups: right-sided-dominant and left-sided-dominant. The differences between the groups were analyzed using an unpaired 2-group t test. The results showed that location of the thoracic humps and inclination of the cervical spine was predominantly right-sided, while the location of lumbar prominence was predominantly left-sided. Craniofacial morphological variables of the head and face were nearly equal for right-sided and left-sided thoracic humps and lumbar prominences, showing that moderate trunk asymmetry does not affect facial symmetry. Further, it was found that frontal head position in relation to the true vertical (VER/ORB) is stable in that the angle between the supraorbital and vertical lines is constantly maintained close to 90 degrees regardless of moderate trunk asymmetry, indicating that visual perception control is most important in orienting the head in frontal plane. Maintenance of the head position takes place by cervical spine adaptation.

Adaptation, Physiological↗

Effect of trunk rotation and arm position on gross upper extremity adduction strength and muscular activity.

The aim of the experiment was to determine the impact of axial trunk rotation and arm position on upper extremity adduction force and muscle activity. Ten healthy male subjects performed graded maximum voluntary contractions under isometric conditions in seven upper extremity positions and three trunk postures (neutral and 90 degrees left/right rotated) in a simulated manual materials handling task. A custom built lightweight force-measuring device was held between the palmar surfaces of the hands and subjects compressed the lateral surfaces of the device. Muscle activity was recorded bilaterally over the muscle bellies of the anterior deltoid, the long head of the biceps brachii and over the flexor carpi radialis. The activity of the right pectoralis major was also recorded unilaterally. Descriptive, multivariate analysis of variance (MANOVA) and post-hoc Scheffé comparisons were performed on the mean and peak force as well as the EMG [electromyographic] data. Further analysis was performed on the force-EMG relationship at 20% intervals of maximum voluntary contraction (force). Both upper extremity adduction force and EMG were significantly affected by position (p<0.01) but not by trunk rotation. The muscle activity increased and force decreased with flexion of the upper extremity. Pearson correlation coefficients between force and EMG were low. The biceps and flexors were the most active muscles depending upon upper extremity position, and the right pectoralis major muscle activity expressed the highest correlation with force. The present findings confirm earlier hypotheses that upper extremity adduction strength is not significantly affected by trunk rotation.

Adult↗

Measuring trunk motions in industry: variability due to task factors, individual differences, and the amount of data collected.

The focus of this study was to determine the amount of data needed to ensure sufficient accuracy in estimating mean trunk motions of employees performing industrial manual materials handling tasks. Over 450 tasks were selected, in which the load weight and the vertical start and destination heights of the activity remained constant throughout the task. Data were collected as employees did their work at the job site, using the Lumbar Motion Monitor. Variance components were estimated in a hierarchical design and used to compute standard errors of mean trunk kinematic measures. These analyses found task-to-task variation to be much larger than the variability due to either multiple employees performing the same task or to repetitive movements within a task. Also, it was found that no significant reduction in the standard errors occurred when data were gathered for more than three employees and three repetitions of each task by an employee. This study indicates that the vast majority of variability in mean trunk motions is accounted for by the design of work tasks, and variations due to repeated cycles of a task or to employees are rather minor. It is also important as a basis for future work on modelling low-back disorder risk based on a job's trunk kinematic measures.

Adult↗

A neuro-fuzzy model for estimating electromyographical activity of trunk muscles due to manual lifting.

The main objective of this study was to develop a hybrid neuro-fuzzy system for estimating the magnitude of EMG responses of 10 trunk muscles based on two lifting task variables (trunk velocity and trunk moment) as model inputs. The input and output variables were represented using the fuzzy membership functions. The initial fuzzy rules were generated by the neural network using true EMG data. Two different laboratory-derived EMG data sets were used for model development and validation, respectively. The mean absolute error (MAE) between the actual and model-estimated normalized EMG values was calculated. Across all muscles, the average value of MAE was 8.43% (SD=2.87%) of the normalized EMG data. The larger absolute errors occurred in the left side of the trunk, which exhibited higher levels of muscular activity. Overall, the developed model was capable of estimating the normalized EMG values with average value of the mean absolute differences of 6.4%. It was hypothesized that model performance could be improved by increasing the number of inputs, including additional task variables as well as the subjects' characteristics.

Biomechanical Phenomena↗