WorldWideScience
 
 
1

NEUROMUSCULAR CONTROL IN LUMBAR DISORDERS  

Directory of Open Access Journals (Sweden)

Full Text Available Impaired motor and sensory functions have been associated with low back pain (LBP). This includes disturbances in a wide range of sensorimotor control e.g. sensory dysfunctions, impaired postural responses and psychomotor control. However, the physiological mechanisms, clinical relevance and characteristics of these findings in different spinal pathologies require further clarification. The purposes of this study were to investigate postural control, lumbar muscle function, movement perception and associations between these findings in healthy volunteers (n=35), patients with lumbar disc herniation (n=20) and lumbar spinal stenosis (LSS, n=26). Paraspinal muscle responses for sudden upper limb loading and muscle activation during flexion-extension movement and the lumbar endurance test were measured by surface electromyography (EMG). Postural stability was measured on a force platform during two- and one-footed standing. Lumbar movement perception was assessed in a motorised trunk rotation unit in the seated position. In addition, measurements of motor-(MEP) and somatosensory evoked potentials (SEP) and needle EMG examination of lumbar multifidus muscles were performed in the LSS patients. Clinical and questionnaire data were also recorded. A short latency paraspinal muscle response (~50 ms) for sudden upper limb loading was observed. The latency of the response was shortened by expectation (p=0.017). The response latency for unexpected loading was similar in healthy persons and disc herniation patients but the latency was not shortened by expectation in the patients (p = 0.014). Also impaired postural control (p < 0.05) and lumbar movement perception (p = 0.012) were observed in disc herniation patients. The impaired lumbar movement perception (p=0.054) and anticipatory muscle activation (p = 0.043) tended to be restored after successful surgery but postural control had still not recovered after 3 months of follow-up. The majority of LSS patients were unable to sense a rotational movement in the lumbar area and thus had clearly impaired lumbar movement perception (p = 0.006). Abnormal MEPs had only inconsistent and SEPs showed no associations with impaired movement perception and postural stability in LSS. Abnormal needle EMG findings and flexion-extension activation of paraspinal muscles were frequently observed in LSS patients. Lumbar paraspinal muscle endurance was better than in previously evaluated healthy subjects and chronic LBP patients (p < 0.001). The results demonstrated clearly impaired lumbar sensory and motor function in sciatica and LSS patients. The pure reflex activation of paraspinal muscles was not affected in sciatica but a difference was found in the premotoneuronal response control. The impaired proprioceptive functions and premotoneuronal response control seem to recover at least partially but the maintenance of postural stability is a complex activity which does not seem to recover automatically in operated sciatica patients at least in three months follow-up. Paraspinal muscle denervation and dysfunction were clearly detectable in LSS but lumbar paraspinal muscle endurance was unexpectedly good.

Ville Leinonen

2004-01-01

2

NEUROMUSCULAR CONTROL IN LUMBAR DISORDERS  

Directory of Open Access Journals (Sweden)

Full Text Available Impaired motor and sensory functions have been associated with low back pain (LBP). This includes disturbances in a wide range of sensorimotor control e.g. sensory dysfunctions, impaired postural responses and psychomotor control. However, the physiological mechanisms, clinical relevance and characteristics of these findings in different spinal pathologies require further clarification.The purposes of this study were to investigate postural control, lumbar muscle function, movement perception and associations between these findings in healthy volunteers (n=35), patients with lumbar disc herniation (n=20) and lumbar spinal stenosis (LSS, n=26).Paraspinal muscle responses for sudden upper limb loading and muscle activation during flexion-extension movement and the lumbar endurance test were measured by surface electromyography (EMG). Postural stability was measured on a force platform during two- and one-footed standing. Lumbar movement perception was assessed in a motorised trunk rotation unit in the seated position. In addition, measurements of motor-(MEP) and somatosensory evoked potentials (SEP) and needle EMG examination of lumbar multifidus muscles were performed in the LSS patients. Clinical and questionnaire data were also recorded. A short latency paraspinal muscle response (~50 ms) for sudden upper limb loading was observed. The latency of the response was shortened by expectation (p=0.017). The response latency for unexpected loading was similar in healthy persons and disc herniation patients but the latency was not shortened by expectation in the patients (p = 0.014). Also impaired postural control (p < 0.05) and lumbar movement perception (p = 0.012) were observed in disc herniation patients. The impaired lumbar movement perception (p=0.054) and anticipatory muscle activation (p = 0.043) tended to be restored after successful surgery but postural control had still not recovered after 3 months of follow-up. The majority of LSS patients were unable to sense a rotational movement in the lumbar area and thus had clearly impaired lumbar movement perception (p = 0.006). Abnormal MEPs had only inconsistent and SEPs showed no associations with impaired movement perception and postural stability in LSS. Abnormal needle EMG findings and flexion-extension activation of paraspinal muscles were frequently observed in LSS patients. Lumbar paraspinal muscle endurance was better than in previously evaluated healthy subjects and chronic LBP patients (p < 0.001).The results demonstrated clearly impaired lumbar sensory and motor function in sciatica and LSS patients. The pure reflex activation of paraspinal muscles was not affected in sciatica but a difference was found in the premotoneuronal response control. The impaired proprioceptive functions and premotoneuronal response control seem to recover at least partially but the maintenance of postural stability is a complex activity which does not seem to recover automatically in operated sciatica patients at least in three months follow-up. Paraspinal muscle denervation and dysfunction were clearly detectable in LSS but lumbar paraspinal muscle endurance was unexpectedly good

Ville Leinonen

2004-01-01

3

[Molecular mechanisms underlying the formation of neuromuscular junction].  

UK PubMed Central (United Kingdom)

The neuromuscular junction (NMJ) is a synapse between a motor neuron and skeletal muscle. The contraction of skeletal muscle is controlled by the neurotransmitter acetylcholine (ACh), which is released from the motor nerve terminal. To achieve efficient neuromuscular transmission, acetylcholine receptors (AChRs) must be densely clustered on the muscle membrane of the NMJ. Failure of AChR clustering is associated with disorders of neuromuscular transmission such as congenital myasthenic syndromes (CMS) and myasthenia gravis (MG). Motoneuronal agrin and muscle-specific receptor tyrosine kinase (MuSK) are known to play essential roles in the formation and maintenance of NMJs in the central region of each muscle. However, it had been unclear how agrin activates MuSK. Recent studies have elucidated the roles of several key molecules, including the cytoplasmic adaptor protein Dok-7 and LDL receptor-related protein 4 (Lrp4), in agrin-induced MuSK activation. Moreover, new evidence indicates that cyclin-dependent kinase 5 (Cdk5) regulates postsynaptic differentiation. In this review, we summarize the latest developments in molecular mechanisms underlying NMJ formation in vertebrates.

Higuchi O; Yamanashi Y

2011-07-01

4

Proprioceptive Neuromuscular Facilitation (PNF): Its Mechanisms and Effects on Range of Motion and Muscular Function.  

UK PubMed Central (United Kingdom)

Proprioceptive neuromuscular facilitation (PNF) is common practice for increasing range of motion, though little research has been done to evaluate theories behind it. The purpose of this study was to review possible mechanisms, proposed theories, and physiological changes that occur due to proprioceptive neuromuscular facilitation techniques. Four theoretical mechanisms were identified: autogenic inhibition, reciprocal inhibition, stress relaxation, and the gate control theory. The studies suggest that a combination of these four mechanisms enhance range of motion. When completed prior to exercise, proprioceptive neuromuscular facilitation decreases performance in maximal effort exercises. When this stretching technique is performed consistently and post exercise, it increases athletic performance, along with range of motion. Little investigation has been done regarding the theoretical mechanisms of proprioceptive neuromuscular facilitation, though four mechanisms were identified from the literature. As stated, the main goal of proprioceptive neuromuscular facilitation is to increase range of motion and performance. Studies found both of these to be true when completed under the correct conditions. These mechanisms were found to be plausible; however, further investigation needs to be conducted. All four mechanisms behind the stretching technique explain the reasoning behind the increase in range of motion, as well as in strength and athletic performance. Proprioceptive neuromuscular facilitation shows potential benefits if performed correctly and consistently.

Hindle KB; Whitcomb TJ; Briggs WO; Hong J

2012-03-01

5

The role of intrinsic muscle mechanics in the neuromuscular control of stable running in the guinea fowl.  

UK PubMed Central (United Kingdom)

Here we investigate the interplay between intrinsic mechanical and neural factors in muscle contractile performance during running, which has been less studied than during walking. We report in vivo recordings of the gastrocnemius muscle of the guinea fowl (Numida meleagris), during the response and recovery from an unexpected drop in terrain. Previous studies on leg and joint mechanics following this perturbation suggested that distal leg extensor muscles play a key role in stabilisation. Here, we test this through direct recordings of gastrocnemius fascicle length (using sonomicrometry), muscle-tendon force (using buckle transducers), and activity (using indwelling EMG). Muscle recordings were analysed from the stride just before to the second stride following the perturbation. The gastrocnemius exhibits altered force and work output in the perturbed and first recovery strides. Muscle work correlates strongly with leg posture at the time of ground contact. When the leg is more extended in the drop step, net gastrocnemius work decreases (-5.2 J kg(-1) versus control), and when the leg is more flexed in the step back up, it increases (+9.8 J kg(-1) versus control). The muscle's work output is inherently stabilising because it pushes the body back toward its pre-perturbation (level running) speed and leg posture. Gastrocnemius length and force return to level running means by the second stride following the perturbation. EMG intensity differs significantly from level running only in the first recovery stride following the perturbation, not within the perturbed stride. The findings suggest that intrinsic mechanical factors contribute substantially to the initial changes in muscle force and work. The statistical results suggest that a history-dependent effect, shortening deactivation, may be an important factor in the intrinsic mechanical changes, in addition to instantaneous force-velocity and force-length effects. This finding suggests the potential need to incorporate history-dependent muscle properties into neuromechanical simulations of running, particularly if high muscle strains are involved and stability characteristics are important. Future work should test whether a Hill or modified Hill type model provides adequate prediction in such conditions. Interpreted in light of previous studies on walking, the findings support the concept of speed-dependent roles of reflex feedback.

Daley MA; Voloshina A; Biewener AA

2009-06-01

6

The role of intrinsic muscle mechanics in the neuromuscular control of stable running in the guinea fowl.  

Science.gov (United States)

Here we investigate the interplay between intrinsic mechanical and neural factors in muscle contractile performance during running, which has been less studied than during walking. We report in vivo recordings of the gastrocnemius muscle of the guinea fowl (Numida meleagris), during the response and recovery from an unexpected drop in terrain. Previous studies on leg and joint mechanics following this perturbation suggested that distal leg extensor muscles play a key role in stabilisation. Here, we test this through direct recordings of gastrocnemius fascicle length (using sonomicrometry), muscle-tendon force (using buckle transducers), and activity (using indwelling EMG). Muscle recordings were analysed from the stride just before to the second stride following the perturbation. The gastrocnemius exhibits altered force and work output in the perturbed and first recovery strides. Muscle work correlates strongly with leg posture at the time of ground contact. When the leg is more extended in the drop step, net gastrocnemius work decreases (-5.2 J kg(-1) versus control), and when the leg is more flexed in the step back up, it increases (+9.8 J kg(-1) versus control). The muscle's work output is inherently stabilising because it pushes the body back toward its pre-perturbation (level running) speed and leg posture. Gastrocnemius length and force return to level running means by the second stride following the perturbation. EMG intensity differs significantly from level running only in the first recovery stride following the perturbation, not within the perturbed stride. The findings suggest that intrinsic mechanical factors contribute substantially to the initial changes in muscle force and work. The statistical results suggest that a history-dependent effect, shortening deactivation, may be an important factor in the intrinsic mechanical changes, in addition to instantaneous force-velocity and force-length effects. This finding suggests the potential need to incorporate history-dependent muscle properties into neuromechanical simulations of running, particularly if high muscle strains are involved and stability characteristics are important. Future work should test whether a Hill or modified Hill type model provides adequate prediction in such conditions. Interpreted in light of previous studies on walking, the findings support the concept of speed-dependent roles of reflex feedback. PMID:19359369

Daley, Monica A; Voloshina, Alexandra; Biewener, Andrew A

2009-04-09

7

THE ANALYSIS OF NEUROMUSCULAR MECHANISMS IN CHITON.  

UK PubMed Central (United Kingdom)

1. The degree of curvature of the body and of the girdle of a Chiton is determined by the activity of antagonistic muscle groups. At a certain, early stage in the strychninization of a Chiton the reciprocal inhibition involved in the natural use of these muscle groups is reversed, such that extensor muscles, rather than, as normally, flexor muscles, contract as the result of stimulation. This condition involves a reversal, under strychnine, of the normally positive stereotropism of the foot, and of the usual response of the mollusk to an increased illumination of its ventral surface. Strychnine reversal of this character is not a matter of the relative strength of the opposed muscle groups, for the flexor muscles are the more powerful and are the ones always shortened in tetanic contraction. 2. Nicotine, in contrast to strychnine, primarily induces contraction of flexor muscles. Its effects, moreover, are in a degree selective, being notably exerted on "cerebral" nervous structures. Curare is devoid of characteristic action on the neuromuscular responses of Chiton. 3. The chemical organization of the neuromuscular organs of Chiton, as far as revealed by these tests, corresponds to a more simple condition than is inferred for gastropods. In particular, the behavior with respect to curare resembles more that of the neuromuscular apparatus of flatworms.

Crozier WJ

1920-07-01

8

Functional instability of the ankle and the role of neuromuscular control: a comprehensive review.  

UK PubMed Central (United Kingdom)

A review of current knowledge of the clinical syndrome of functional ankle instability is presented. Recent evidence has demonstrated that the majority of patients with functional instability of the ankle do not have mechanical hypermobility of the ankle joint. Functional instability of the ankle results from a loss of neuromuscular control. Components of neuromuscular control include proprioception, muscle strength, muscle reaction time, and postural control. Proprioceptive deficits lead to a delay in peroneal reaction time, which appears to be a peripheral reflex. Proprioception and eversion muscle strength improve with the use of passive supportive devices. Balance and postural control of the ankle appear to be diminished after a lateral ankle sprain and can be restored through training that is mediated through central nervous mechanisms. Methods of detecting deficits in neuromuscular control are presented along with rehabilitation techniques to treat functional instability of the ankle.

Richie DH Jr

2001-07-01

9

Functional instability of the ankle and the role of neuromuscular control: a comprehensive review.  

Science.gov (United States)

A review of current knowledge of the clinical syndrome of functional ankle instability is presented. Recent evidence has demonstrated that the majority of patients with functional instability of the ankle do not have mechanical hypermobility of the ankle joint. Functional instability of the ankle results from a loss of neuromuscular control. Components of neuromuscular control include proprioception, muscle strength, muscle reaction time, and postural control. Proprioceptive deficits lead to a delay in peroneal reaction time, which appears to be a peripheral reflex. Proprioception and eversion muscle strength improve with the use of passive supportive devices. Balance and postural control of the ankle appear to be diminished after a lateral ankle sprain and can be restored through training that is mediated through central nervous mechanisms. Methods of detecting deficits in neuromuscular control are presented along with rehabilitation techniques to treat functional instability of the ankle. PMID:11924686

Richie, D H

10

Neuromuscular control of free-flight yaw turns in the hawkmoth Manduca sexta.  

UK PubMed Central (United Kingdom)

The biomechanical properties of an animal's locomotor structures profoundly influence the relationship between neuromuscular inputs and body movements. In particular, passive stability properties are of interest as they may offer a non-neural mechanism for simplifying control of locomotion. Here, we hypothesized that a passive stability property of animal flight, flapping counter-torque (FCT), allows hawkmoths to control planar yaw turns in a damping-dominated framework that makes rotational velocity directly proportional to neuromuscular activity. This contrasts with a more familiar inertia-dominated framework where acceleration is proportional to force and neuromuscular activity. To test our hypothesis, we collected flight muscle activation timing, yaw velocity and acceleration data from freely flying hawkmoths engaged in planar yaw turns. Statistical models built from these data then allowed us to infer the degree to which the moths inhabit either damping- or inertia-dominated control domains. Contrary to our hypothesis, a combined model corresponding to inertia-dominated control of yaw but including substantial damping effects best linked the neuromuscular and kinematic data. This result shows the importance of including passive stability properties in neuromechanical models of flight control and reveals possible trade-offs between manoeuvrability and stability derived from damping.

Springthorpe D; Fernández MJ; Hedrick TL

2012-05-01

11

Young men utilise limited neuromuscular preparation to regulate post-impact knee mechanics during step landing.  

UK PubMed Central (United Kingdom)

PURPOSE: The neuromuscular mechanisms determining the mechanical behaviour of the knee during landing impact remain poorly understood. It was hypothesised that neuromuscular preparation is subject-specific and ranges along a continuum from passive to active. METHODS: A group of healthy men (N=12) stepped-down from a knee-high platform for 60 consecutive trials. Surface EMG of the quadriceps and hamstrings was used to determine pre-impact onset timing, activation amplitude and cocontraction for each trial. Partial least squares regression was used to associate pre-impact preparation with post-impact knee stiffness and coordination. RESULTS: The group analysis revealed few significant changes in pre-impact preparation across trial blocks. Single-subject analyses revealed changes in muscle activity that varied in size and direction between individuals. Further, the association between pre-impact preparation and post-impact knee mechanics was subject-specific and ranged along a continuum of strategies. CONCLUSION: The findings suggest that neuromuscular preparation during step landing is subject-specific and its association to post-impact knee mechanics occurs along a continuum, ranging from passive to active control strategies. Further work should examine the implications of these strategies on the distribution of knee forces in vivo.

Scholes CJ; McDonald MD; Parker AW

2013-08-01

12

Invasive home mechanical ventilation, mainly focused on neuromuscular disorders  

Directory of Open Access Journals (Sweden)

Full Text Available Introduction and background: Invasive home mechanical ventilation is used for patients with chronic respiratory insufficiency. This elaborate and technology-dependent ventilation is carried out via an artificial airway (tracheal cannula) to the trachea. Exact numbers about the incidence of home mechanical ventilation are not available. Patients with neuromuscular diseases represent a large portion of it. Research questions: Specific research questions are formulated and answered concerning the dimensions of medicine/nursing, economics, social, ethical and legal aspects. Beyond the technical aspect of the invasive home, mechanical ventilation, medical questions also deal with the patient’s symptoms and clinical signs as well as the frequency of complications. Economic questions pertain to the composition of costs and the differences to other ways of homecare concerning costs and quality of care. Questions regarding social aspects consider the health-related quality of life of patients and caregivers. Additionally, the ethical aspects connected to the decision of home mechanical ventilation are viewed. Finally, legal aspects of financing invasive home mechanical ventilation are discussed. Methods: Based on a systematic literature search in 2008 in a total of 31 relevant databases current literature is viewed and selected by means of fixed criteria. Randomized controlled studies, systematic reviews and HTA reports (health technology assessment), clinical studies with patient numbers above ten, health-economic evaluations, primary studies with particular cost analyses and quality-of-life studies related to the research questions are included in the analysis. Results and discussion: Invasive mechanical ventilation may improve symptoms of hypoventilation, as the analysis of the literature shows. An increase in life expectancy is likely, but for ethical reasons it is not confirmed by premium-quality studies. Complications (e. g. pneumonia) are rare. Mobile home ventilators are available for the implementation of the ventilation. Their technical performance however, differs regrettably. Studies comparing the economic aspects of ventilation in a hospital to outpatient ventilation, describe home ventilation as a more cost-effective alternative to in-patient care in an intensive care unit, however, more expensive in comparison to a noninvasive (via mask) ventilation. Higher expenses arise due to the necessary equipment and the high expenditure of time for the partial 24-hour care of the affected patients through highly qualified personnel. However, none of the studies applies to the German provisionary conditions. The calculated costs strongly depend on national medical fees and wages of caregivers, which barely allows a transmission of the results. The results of quality-of-life studies are mostly qualitative. The patient’s quality of life using mechanical ventilation is predominantly considered well. Caregivers of ventilated patients report positive as well as negative ratings. Regarding the ethical questions, it was researched which aspects of ventilation implementation will have to be considered. From a legal point of view the financing of home ventilation, especially invasive mechanical ventilation, requiring specialised technical nursing is regulated in the code of social law (Sozialgesetzbuch V). The absorption of costs is distributed to different insurance carriers, who often, due to cost pressures within the health care system, insurance carriers, who consider others and not themselves as responsible. Therefore in practice, the necessity to enforce a claim of cost absorption often arises in order to exercise the basic right of free choice of location. Conclusion: Positive effects of the invasive mechanical ventilation (overall survival and symptomatic) are highly probable based on the analysed literature, although with a low level of evidence. An establishment of a home ventilation registry and health care research to ascertain valid data to improve outpatient structures is necessary. Gathering spec

Geiseler, Jens; Karg, Ortrud; Börger, Sandra; Becker, Kurt; Zimolong, Andreas

2010-01-01

13

Tai Chi and vestibular rehabilitation improve vestibulopathic gait via different neuromuscular mechanisms: Preliminary report  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Vestibular rehabilitation (VR) is a well-accepted exercise program intended to remedy balance impairment caused by damage to the peripheral vestibular system. Alternative therapies, such as Tai Chi (TC), have recently gained popularity as a treatment for balance impairment. Although VR and TC can benefit people with vestibulopathy, the degree to which gait improvements may be related to neuromuscular adaptations of the lower extremities for the two different therapies are unknown. Methods We examined the relationship between lower extremity neuromuscular function and trunk control in 36 older adults with vestibulopathy, randomized to 10 weeks of either VR or TC exercise. Time-distance measures (gait speed, step length, stance duration and step width), lower extremity sagittal plane mechanical energy expenditures (MEE), and trunk sagittal and frontal plane kinematics (peak and range of linear and angular velocity), were measured. Results Although gait time-distance measures were improved in both groups following treatment, no significant between-groups differences were observed for the MEE and trunk kinematic measures. Significant within groups changes, however, were observed. The TC group significantly increased ankle MEE contribution and decreased hip MEE contribution to total leg MEE, while no significant changes were found within the VR group. The TC group exhibited a positive relationship between change in leg MEE and change in trunk velocity peak and range, while the VR group exhibited a negative relationship. Conclusion Gait function improved in both groups consistent with expectations of the interventions. Differences in each group's response to therapy appear to suggest that improved gait function may be due to different neuromuscular adaptations resulting from the different interventions. The TC group's improvements were associated with reorganized lower extremity neuromuscular patterns, which appear to promote a faster gait and reduced excessive hip compensation. The VR group's improvements, however, were not the result of lower extremity neuromuscular pattern changes. Lower-extremity MEE increases corresponded to attenuated forward trunk linear and angular movement in the VR group, suggesting better control of upper body motion to minimize loss of balance. These data support a growing body of evidence that Tai Chi may be a valuable complementary treatment for vestibular disorders.

McGibbon Chris A; Krebs David E; Parker Stephen W; Scarborough Donna M; Wayne Peter M; Wolf Steven L

2005-01-01

14

Neuromuscular control of childbirth-prepared women during the first stage of labor.  

Science.gov (United States)

To evaluate the neuromuscular control of Lamaze-prepared women during the first stage of labor and to identify the factors which influenced control, 94 women were studied. The women were categorized into two groups: class-taught and self-taught. A tool was devised to evaluate neuromuscular control. The study revealed that class-taught women exhibited a significantly higher degree of neuromuscular control, more frequent practice patterns, and a greater ability to make goal-directed statements about their labor than the self-taught women. The data also demonstrated an association between practice and control and goal directedness and control. PMID:6551540

Bernardini, J Y; Maloni, J A; Stegman, C E

15

Neuromuscular blockade in children  

Directory of Open Access Journals (Sweden)

Full Text Available Neuromuscular blocking agents (NMBAs) have been widely used to control patients who need to be immobilized for some kind of medical intervention, such as an invasive procedure or synchronism with mechanical ventilation. The purpose of this monograph is to review the pharmacology of the NMBAs, to compare the main differences between the neuromuscular junction in neonates, infants, toddlers and adults, and moreover to discuss their indications in critically ill pediatric patients. Continuous improvement of knowledge about NMBAs pharmacology, adverse effects, and the many other remaining unanswered questions about neuromuscular junction and neuromuscular blockade in children is essential for the correct use of these drugs. Therefore, the indication of these agents in pediatrics is determined with extreme judiciousness. Computorized (Medline 1990-2000) and active search of articles were the mechanisms used in this review.

Almeida João Fernando Lourenço de; Kalil Filho W. Jorge; Troster Eduardo J.

2000-01-01

16

Energy expenditure in patients with severe head injury: controlled normothermia with sedation and neuromuscular blockade.  

UK PubMed Central (United Kingdom)

OBJECTIVES: Providing optimal caloric intake is important for patients with severe traumatic brain injury. Insufficient nutrition worsens prognosis, and excessive nutrition may lead to complications such as weaning delay from mechanical ventilation. However, using controlled normothermia with sedation and neuromuscular blockade for patients with anticipated severe brain edema, the optimal caloric intake is still unclear. METHODS: Ten patients with severe traumatic brain injury were studied. All patients received midazolam and vecuronium or pancuronium to control body temperature to 36.0°C. Energy expenditure was measured using indirect calorimetry. Age, body height, body weight, heart rate, blood pressure, body temperature, and minute ventilation volume were evaluated at the time of the study. Differences between the mean measured energy expenditures (MEEs) and predicted basal energy expenditures (PEEs from the Harris-Benedict equation) were analyzed using paired t test. Furthermore, the relationships between these variables and MEEs were analyzed with multiple regression analysis. RESULTS: The result of MEE was 1279±244 kcal/d. When compared with PEE, MEE/PEE was 87.2% ± 10%. Multiple regression analysis showed that age, body height, body weight, heart rate, and minute ventilation volume were related with MEE. CONCLUSIONS: Energy expenditure in patients with severe traumatic brain injury who need mechanical ventilation and have received controlled normothermia with sedation and neuromuscular blockade was 13% less than predicted basal levels. Energy expenditure might be obtained from age, body height, body weight, heart rate, and minute ventilation.

Osuka A; Uno T; Nakanishi J; Hinokiyama H; Takahashi Y; Matsuoka T

2013-04-01

17

Sensory-motor control of ligaments and associated neuromuscular disorders.  

UK PubMed Central (United Kingdom)

The ligaments were considered, over several centuries, as the major restraints of the joints, keeping the associated bones in position and preventing instability, e.g. their separation from each other and/or mal-alignment. This project, conducted over 25 years, presents the following hypothesis: 1. Ligaments are also major sensory organs, capable of monitoring relevant kinesthetic and proprioceptive data. 2. Excitatory and inhibitory reflex arcs from sensory organs within the ligaments recruit/de-recruit the musculature to participate in maintaining joint stability as needed by the movement type performed. 3. The synergy of the ligament and associated musculature allocates prominent role for muscles in maintaining joint stability. 4. The viscoelastic properties of ligaments and their classical responses to static and cyclic loads or movements such as creep, tension-relaxation, hysteresis and strain rate dependence decreases their effectiveness as joint restraint and stabilizers and as sensory organs and exposes the joint to injury. 5. Long-term exposure of ligaments to static or cyclic loads/movements in a certain dose-duration paradigms consisting of high loads, long loading duration, high number of load repetitions, high frequency or rate of loading and short rest periods develops acute inflammatory responses which require long rest periods to resolve. These inflammatory responses are associated with a temporary (acute) neuromuscular disorder and during such period high exposure to injury is present. 6. Continued exposure of an inflamed ligament to static or cyclic load may result in a chronic inflammation and the associated chronic neuromuscular disorder known as cumulative trauma disorder (CTD). 7. The knowledge gained from basic and applied research on the sensory - motor function of ligaments can be used as infrastructure for translational research; mostly for the development of "smart orthotic" systems for ligament deficient patients. Three such "smart orthosis", for the knee and lumbar spine are described. 8. The knowledge gained from the basic and applied research manifests in new physiotherapy modalities for ligament deficient patients. Ligaments, therefore, are important structures with significant impact on motor control and a strong influence on the quality of movement, safety/stability of the joint and potential disorders that impact the safety and health of workers and athletes.

Solomonow M

2006-12-01

18

Molecular mechanisms underlying maturation and maintenance of the vertebrate neuromuscular junction.  

UK PubMed Central (United Kingdom)

The vertebrate neuromuscular junction (NMJ), a peripheral synapse formed between motoneuron and skeletal muscle, is characterized by a protracted postnatal period of maturation and life-long maintenance. In neuromuscular disorders such as congenital myasthenic syndromes (CMSs), disruptions of NMJ maturation and/or maintenance are frequently observed. In particular, defective neuromuscular transmission associated with structural and molecular abnormalities at the pre- and postsynaptic membranes, as well as at the synaptic cleft, has been reported in these patients. Here, we review recent advances in the understanding of molecular and cellular events that mediate NMJ maturation and maintenance. The underlying regulatory mechanisms, including key molecular regulators at the presynaptic nerve terminal, synaptic cleft, and postsynaptic muscle membrane, are discussed.

Shi L; Fu AK; Ip NY

2012-07-01

19

Hypohydration and hyperthermia impair neuromuscular control after exercise.  

UK PubMed Central (United Kingdom)

PURPOSE: This study aimed to evaluate the effects of hypohydration and hyperthermia during exercise on movement technique and postural control. METHODS: Twelve healthy men (age = 20 ± 2 yr, height = 182 ± 8 cm, mass = 74.0 ± 8.2 kg, V?O2max = 57.0 ± 6.0 mL·kg·min; mean ± SD) completed four randomized test sessions: euhydrated temperate (EUT), euhydrated hot (EUH), hypohydrated temperate (HYT), and hypohydrated hot (HYH). Temperate and hot conditions were performed in 18.0°C ± 0.2°C, 50.0% ± 3.5% relative humidity, and 34.0°C ± 0.3°C, 45.0% ± 4.5% relative humidity, respectively. Movement technique and postural control were assessed before exercise (PRE), after exercise (POST), and after recovery (REC). Movement technique was evaluated using the Landing Error Scoring System (LESS). Postural control was assessed using the Balance Error Scoring System (BESS) and center-of-pressure sway velocity (SV) and elliptical sway area (ESA) during a dynamic balance test. The 90-min treadmill exercise protocol (1.34-1.78 m·s; 5% grade) required subjects to walk carrying a 20.5-kg rucksack. Subjects sat quietly in the test environment during a 60-min recovery period after exercise. Repeated-measures ANOVAs with a Tukey-HSD post hoc test evaluated differences between time and condition for dependent variables. RESULTS: Exercise during HYH significantly increased LESS scores (PRE = 3.72 ± 1.73, POST = 4.42 ± 1.75) compared with HYT (3.75 ± 1.76) and EUH (3.61 ± 1.71) (P < 0.05). LESS scores remained elevated during REC for HYH compared with EUT (4.39 ± 1.47 vs 3.47 ± 2.05, P < 0.05). The HYH condition caused the greatest number of BESS errors (P = 0.02), largest ESA (P < 0.05), and highest SV (P = 0.02). Regardless of the condition, participants had the most BESS errors (P = 0.002) and highest SV (P = 0.003) during POST compared with the PRE and REC. CONCLUSIONS: Hypohydration during exercise in the heat impairs neuromuscular control. These findings suggest that physical activity in the heat while dehydrated may affect parameters associated with a higher risk of injury.

Distefano LJ; Casa DJ; Vansumeren MM; Karslo RM; Huggins RA; Demartini JK; Stearns RL; Armstrong LE; Maresh CM

2013-06-01

20

Assessment of neuromuscular control in patients after anterior cruciate ligament reconstruction.  

UK PubMed Central (United Kingdom)

BACKGROUND: The anterior cruciate ligament (ACL) is one of the most important stabilisers of the knee joint. The key role of ACL is to resist anterior translation of the tibia in relation to the femur. At the same time, ACL does not only perform a mechanical limiting function, but is also an important component of the sensorimotor system. The aim of this study was to assess neuromuscular control in patients after ACL reconstruction by evaluatingthe maintenance of dynamic balance. MATERIAL AND METHODS: Twenty-six patients (aged 28.4±6.3 years) after ACL reconstruction (ACLR group) were enrolled. All patients had undergone arthroscopic reconstruction of ACL, and were recruited to the study 11-13 months after the surgery. Thirty-seven healthy individuals served as a control group (CTRL). The maintenance of the single-leg and two-leg standing position on an unstable surface was assessed using the Biodex Balance System SD. RESULTS: The ACLR group differed from the control group in the values of the overall stability index (p<0.05; 6.53±2.04, and 5.27±1.42, respectively) when stability control in the two-leg position was assessed. Additionally, in the single-leg position, the values of the study parameters were significantly higher (p<0.05) in ACLR in comparison to CTRL: 9.73±2.55 vs.7.23±1.48, and 9.42±2.38 vs. 5.64±1.51 respectively, for the dominant and non-dominant leg. CONCLUSIONS: At one year after ACL reconstruction, significant deficits of neuromuscular control were observed during motor tasks requiring considerable sensorimotor system involvement.

B?czkowicz D; Skomudek A

2013-06-01

 
 
 
 
21

[Mechanism of the effect of methylcobalamin on the recovery of neuromuscular functions in mechanical and toxin denervation].  

Science.gov (United States)

It has been shown in experiments on rats that daily administration of methylcobalamine in a dose of 50 micrograms/100 g bw produces marked activation of the regeneration of mechanically damaged axons of motoneurons. Systematic administration of the drug has a protective action on the development of neuromuscular transmission blockade induced by botulinum toxoid. PMID:6653768

Mikha?lov, V V; Mikha?lov, V V; Avakumov, V M

22

[Mechanism of the effect of methylcobalamin on the recovery of neuromuscular functions in mechanical and toxin denervation].  

UK PubMed Central (United Kingdom)

It has been shown in experiments on rats that daily administration of methylcobalamine in a dose of 50 micrograms/100 g bw produces marked activation of the regeneration of mechanically damaged axons of motoneurons. Systematic administration of the drug has a protective action on the development of neuromuscular transmission blockade induced by botulinum toxoid.

Mikha?lov VV; Mikha?lov VV; Avakumov VM

1983-11-01

23

The role of neuromuscular changes in aging and knee osteoarthritis on dynamic postural control.  

UK PubMed Central (United Kingdom)

Knee osteoarthritis (OA) is a chronic joint condition, with 30% of those over the age of 75 exhibiting severe radiographic disease. Nearly 50% of those with knee OA have experienced a fall in the past year. Falls are a considerable public health concern, with a high risk of serious injury and a significant socioeconomic impact. The ability to defend against a fall relies on adequate dynamic postural control, and alterations in dynamic postural control are seen with normal aging. Neuromuscular changes associated with aging may be responsible for some of these alterations in dynamic postural control. Even greater neuromuscular deficits, which may impact dynamic postural control and the ability to defend against a fall, are seen in people with knee OA. There is little evidence to date on how knee OA affects the ability to respond to and defend against falls and the neuromuscular changes that contribute to balance deficits. As a result, this review will: summarize the key characteristics of postural responses to an external perturbation, highlight the changes in dynamic postural control seen with normal aging, review the neuromuscular changes associated with aging that have known and possible effects on dynamic postural control, and summarize the neuromuscular changes and balance problems in knee OA. Future research to better understand the role of neuromuscular changes in knee OA and their effect on dynamic postural control will be suggested. Such an understanding is critical to the successful creation and implementation of fall prevention and treatment programs, in order to reduce the excessive risk of falling in knee OA.

Takacs J; Carpenter MG; Garland SJ; Hunt MA

2013-04-01

24

Treatment With Neuromuscular Blocking Agents and the Risk of In-Hospital Mortality Among Mechanically Ventilated Patients With Severe Sepsis.  

UK PubMed Central (United Kingdom)

OBJECTIVES:: Recent trials suggest that treatment with neuromuscular blocking agents may improve survival in patients requiring mechanical ventilation for acute respiratory distress syndrome. We examined the association between receipt of a neuromuscular blocking agent and in-hospital mortality among mechanically ventilated patients with severe sepsis. DESIGN:: A pharmacoepidemiologic cohort study of patients with sepsis and a respiratory infection who had been admitted to intensive care and placed on mechanical ventilation within the first 2 days of hospitalization. We used propensity score matching and instrumental variable methods to compare the outcomes of patients treated with neuromuscular blocking agents within the first 2 hospital days to those who were not. Sensitivity analysis was used to model the effects of a hypothetical unmeasured confounder. SETTING:: Three hundred thirty-nine U.S. hospitals that participated in the Premier Perspective database between 2004 and 2006. PATIENTS:: Seven thousand eight hundred sixty-four patients met inclusion criteria, including 1,818 (23%) who were treated with a neuromuscular blocking agent by hospital day 2. INTERVENTIONS:: None. MEASUREMENTS AND MAIN RESULTS:: Patients who received neuromuscular blocking agents were younger (mean age, 62 vs 68), more likely to be treated with vasopressors (69% vs 65%)and had a lower in-hospital mortality rate (31.9% vs 38.3%, p < 0.001). In 3,518 patients matched on the propensity for treatment, receipt of a neuromuscular blocking agent was associated with a reduced risk of in-hospital mortality (risk ratio, 0.88; 95% CI, 0.80, 0.96). An analysis using the hospital neuromuscular blocking agent-prescribing rate as an instrumental variable found receipt of a neuromuscular blocking agent associated with a 4.3% (95% CI, -11.5%, 1.5%) reduction in in-hospital mortality. CONCLUSIONS:: Among mechanically ventilated patients with severe sepsis and respiratory infection, early treatment with a neuromuscular blocking agent is associated with lower in-hospital mortality.

Steingrub JS; Lagu T; Rothberg MB; Nathanson BH; Raghunathan K; Lindenauer PK

2013-08-01

25

Air leaks during mechanical ventilation as a cause of persistent hypercapnia in neuromuscular disorders.  

UK PubMed Central (United Kingdom)

OBJECTIVE: This study investigated whether air leaks from the upper airway during assisted ventilatory support are associated with persistent hypercapnia (PaCO(2) >45 mmHg) in patients with neuromuscular disorders. SETTING: A rehabilitation hospital. PATIENTS: The study was performed in 95 neuromuscular patients; 52 were tracheostomized with a cuffless tracheostomy tube (invasive ventilation), and 43 received noninvasive ventilation. MEASUREMENTS AND RESULTS: The volume of air leaked (VL) and arterial carbon dioxide (PaCO(2)) were routinely measured during mechanical ventilation; PaCO(2) was also measured during spontaneous breathing. VL, expressed as a percentage of tidal volume, was higher in the hypercapnic group (32+/-14%, n=20) than the nonhypercapnic group ( vs. 20+/-14%). PaCO(2) during mechanical ventilation was correlated with both VL and the duration of ventilatory support per day; PaCO(2) during spontaneous breathing was correlated only with the volume of air leaked. In stepwise multiple regression analysis, air leaks contributed to 8% of the variance in PaCO(2) during mechanical ventilation, and daily duration of ventilatory support contributed 5%. In addition, reduction in VL with normalization of PaCO(2) was achieved in five of the noninvasively ventilated patients with persistent hypercapnia by using a chin strap. CONCLUSIONS: Air leaks during wakefulness are an important cause of persistent hypercapnia in both invasively and noninvasively ventilated neuromuscular patients. However, simple practical measures to reduce the volume of air leaks improve the efficacy of ventilation in these patients.

Gonzalez J; Sharshar T; Hart N; Chadda K; Raphaël JC; Lofaso F

2003-04-01

26

The mechanism for prejunctional enhancement of neuromuscular transmission by ethanol in the mouse.  

UK PubMed Central (United Kingdom)

Ethanol has been shown to have both presynaptic and postsynaptic effects on synaptic transmission. However, the mechanisms by which ethanol affects evoked neurotransmitter release have not been studied at the mouse neuromuscular junction, a synapse at which binomial analysis of neurotransmitter release and measurements of prejunctional ionic currents can be made. Ethanol (400 mM) increased neurotransmitter release independently of both the cAMP and phorbol ester/Munc13 signaling pathways. Binomial analysis of neurotransmitter release revealed that ethanol increases the average probability of secretion without an effect on the immediately available store of the neurotransmitter. Application of ethanol also resulted in an inhibition of potassium currents in the motor nerve endings. These results suggest that the potentiating effects of ethanol on neurotransmitter release at the skeletal neuromuscular junction are mediated by an inhibition of the delayed rectifier potassium current, thus increasing both calcium entry into the nerve ending and the probability of neurotransmitter release. Identifying the mechanism through which ethanol enhances neurotransmitter release at the neuromuscular junction may be useful in determining the processes underlying the enhancement of neurotransmitter release at other synapses.

Searl TJ; Silinsky EM

2010-11-01

27

Neuromuscular mechanisms and anthropometric modifications in the initial stages of independent gait.  

Science.gov (United States)

The gait acquisition is an important milestone of motor development. Structural modifications observed during this period add complexity to the process, and the child needs to use appropriate neuromuscular strategies to walk independently. The objective of this study was to document the longitudinal modifications in neuromuscular mechanisms and in functional anthropometric measures during independent gait acquisition in typically developing children. Twelve children were followed for 2 months after gait acquisition, with its initial period documented by the standardized test Alberta Infant Motor Scale. Quantification of the EMG signals of six muscles in the right lower limb allowed the calculation of the co-contraction indexes (CCI) considering pairs of antagonistic muscles, representing the hip, knee and ankle joints. The CCIs were summed up to yield a total index. Anthropometric measures were transformed into gravitational torque (mLg) values for stance and swing phases of gait. Statistical analyses included repeated measures ANOVA models with one factor (week post-acquisition) for the dependent variables mLg and normalized CCI (CCI/mLg). A significant increase was observed in the mLg during the period evaluated both in stance and swing phases (p=0.0001). In addition, there was a decrease in the value of the normalized hip and total CCIs in both phases of gait (p<0.05). The results revealed changes in the neuromuscular mechanisms used by typical children to deal with the demands involved in the process of gait acquisition. PMID:16412641

Chagas, P S C; Mancini, M C; Fonseca, S T; Soares, T B C; Gomes, V P D; Sampaio, R F

2006-01-18

28

Neuromuscular mechanisms and anthropometric modifications in the initial stages of independent gait.  

UK PubMed Central (United Kingdom)

The gait acquisition is an important milestone of motor development. Structural modifications observed during this period add complexity to the process, and the child needs to use appropriate neuromuscular strategies to walk independently. The objective of this study was to document the longitudinal modifications in neuromuscular mechanisms and in functional anthropometric measures during independent gait acquisition in typically developing children. Twelve children were followed for 2 months after gait acquisition, with its initial period documented by the standardized test Alberta Infant Motor Scale. Quantification of the EMG signals of six muscles in the right lower limb allowed the calculation of the co-contraction indexes (CCI) considering pairs of antagonistic muscles, representing the hip, knee and ankle joints. The CCIs were summed up to yield a total index. Anthropometric measures were transformed into gravitational torque (mLg) values for stance and swing phases of gait. Statistical analyses included repeated measures ANOVA models with one factor (week post-acquisition) for the dependent variables mLg and normalized CCI (CCI/mLg). A significant increase was observed in the mLg during the period evaluated both in stance and swing phases (p=0.0001). In addition, there was a decrease in the value of the normalized hip and total CCIs in both phases of gait (p<0.05). The results revealed changes in the neuromuscular mechanisms used by typical children to deal with the demands involved in the process of gait acquisition.

Chagas PS; Mancini MC; Fonseca ST; Soares TB; Gomes VP; Sampaio RF

2006-11-01

29

Long term mechanical ventilation equipment for neuromuscular patients: meeting the expectations of patients and prescribers.  

UK PubMed Central (United Kingdom)

BACKGROUND: To maximise the likelihood of successful long term mechanical ventilation (MV) in patients with neuromuscular diseases, ventilators characteristics and settings must be chosen carefully taking into account both medical requisites and the patient's preference and comfort. The general objectives of the survey were 1) to evaluate patients comfort with, and knowledge about, their long term MV; 2) to compare patients and prescribers opinions and expectations regarding long term MV; 3) to compare the equipment used by the patients with prescribers present opinion. METHODS: Neuromuscular patients receiving long term MV and home MV prescribers in Belgium and France and MV prescribers were asked to respond to a questionnaire survey specifically developed for the study. RESULTS: Completed questionnaires were collected from 209 patients, mean age 35.4±15.9 years (range 3 to 86 years), ventilated since 11 ± 17 year, and 45 MV prescribers. Hundred sixty three (78%) patients correctly designed their MV mode as a volume or a pressure targeted mode and 86% considered their MV as "efficient". When an inspiratory trigger was available, 92% of the patients were able to use it but only 72% were satisfied. Prescribers were more prone than patients to use new technologies, such as an emergency system to release a noninvasive interface (visual analogue scale (VAS/10): 9.2±1.5 vs 6.8±3.3, P=0.0001), a humidification system (VAS: 8.6±1.4 vs 7.8±2.6, P=0.02), a contactor for providing larger inspiratory volumes (VAS: 8.4±1.7 vs 6.0±3.0, P=0.009), an in-built cough assistance mode (VAS: 9.2±1.4 vs 5.5±3.3 P=0.00001), new options to improve speech, or new MV modes such as a volume targeted-pressure controlled mode. CONCLUSIONS: Patient's and prescriber's opinion differ about the ideal home ventilator. Patients are less prone to use new technologies, mainly because of a lack of information, underlining the need of regular MV update in patients receiving long term MV.

Lofaso F; Prigent H; Tiffreau V; Menoury N; Toussaint M; Finet Monnier A; Stremler N; Devaux C; Leroux K; Orlikowski D; Mauri C; Pin I; Sacconi S; Pereira C; Pépin JL; Fauroux B

2013-06-01

30

Integration of an adaptive swing control into a neuromuscular human walking model.  

UK PubMed Central (United Kingdom)

Understanding the neuromuscular control underlying human locomotion has the potential to deliver practical controllers for humanoid and prosthetic robots. However, neurocontrollers developed in forward dynamic simulations are seldom applied as practical controllers due to their lack of robustness and adaptability. A key element for robust and adaptive locomotion is swing leg placement. Here we integrate a previously identified robust swing leg controller into a full neuromuscular human walking model and demonstrate that the integrated model has largely improved behaviors including walking on very rough terrain (±10cm) and stair climbing (15cm stairs). These initial results highlight the potential of the identified robust swing control. We plan to generalize it to a range of human locomotion behaviors critical in rehabilitation robotics.

Song S; Desai R; Geyer H

2013-07-01

31

The effects of neuromuscular training on knee joint motor control during sidecutting in female elite soccer and handball players  

DEFF Research Database (Denmark)

OBJECTIVE: The project aimed to implement neuromuscular training during a full soccer and handball league season and to experimentally analyze the neuromuscular adaptation mechanisms elicited by this training during a standardized sidecutting maneuver known to be associated with non-contact anterior cruciate ligament (ACL) injury. DESIGN: The players were tested before and after 1 season without implementation of the prophylactic training and subsequently before and after a full season with the implementation of prophylactic training. PARTICIPANTS: A total of 12 female elite soccer players and 8 female elite team handball players aged 26 +/- 3 years at the start of the study. INTERVENTION: The subjects participated in a specific neuromuscular training program previously shown to reduce non-contact ACL injury. METHODS: Neuromuscular activity at the knee joint, joint angles at the hip and knee, and ground reaction forces were recorded during a sidecutting maneuver. Neuromuscular activity in the prelanding phase was obtained 10 and 50 ms before foot strike on a force plate and at 10 and 50 ms after foot strike on a force plate. RESULTS: Neuromuscular training markedly increased before activity and landing activity electromyography (EMG) of the semitendinosus (P < 0.05), while quadriceps EMG activity remained unchanged. CONCLUSIONS: Neuromuscular training increased EMG activity for the medial hamstring muscles, thereby decreasing the risk of dynamic valgus. This observed neuromuscular adaptation during sidecutting could potentially reduce the risk for non-contact ACL injury.

Zebis, Mette K; Bencke, Jesper

2008-01-01

32

Fatiguing Exercise Intensity Influences the Relationship between Parameters Reflecting Neuromuscular Function and Postural Control Variables.  

UK PubMed Central (United Kingdom)

The purpose of this study was to investigate the influence of fatiguing exercise intensity on the nature and extent of fatigue-induced changes in neuromuscular function and postural stability in quiet standing. We also explored the contribution of selected neuromuscular mechanisms involved in force production to postural stability impairment observed following fatigue using an approach based on multivariate regressions. Eighteen young subjects performed 30-s postural trials on one leg with their eyes closed. Postural trials were performed before and after fatiguing exercises of different intensities: 25, 50 and 75% of maximal isometric plantarflexor torque. Fatiguing exercises consisted of sustaining a plantarflexor isometric contraction at the target intensity until task failure. Maximal isometric plantarflexor torque, electromyographic activity of plantarflexor and dorsiflexor muscles, activation level (twitch interpolation technique) and twitch contractile properties of plantarflexors were used to characterize neuromuscular function. The 25% exercise was associated with greater central fatigue whereas the 50 and 75% exercises involved mostly peripheral fatigue. However, all fatiguing exercises induced similar alterations in postural stability, which was unexpected considering previous literature. Stepwise multiple regression analyses showed that fatigue-related changes in selected parameters related to neuromuscular function could explain more than half (0.51?R(2)?0.82) of the changes in postural variables for the 25% exercise. On the other hand, regression models were less predictive (0.17?R(2)?0.73) for the 50 and 75% exercises. This study suggests that fatiguing exercise intensity does not influence the extent of postural stability impairment, but does influence the type of fatigue induced and the neuromuscular function predictors explaining changes in postural variables.

Boyas S; Remaud A; Rivers E; Bilodeau M

2013-01-01

33

The influence of auditory and visual information on the neuromuscular control of chewing crispy food.  

UK PubMed Central (United Kingdom)

The influence of auditory and/or visual information on the neuromuscular control of chewing a crispy food was investigated. Participants chewed biscuits of three different levels of crispness under four experimental conditions: no masking, auditory masking, visual masking, and auditory plus visual masking. The order of the four masking condition blocks was randomized. The sound of chewing was masked by loud sounds on a headphone, and visual masking of the food was achieved by closing the eyes. Mechanical tests were performed on the biscuits to determine their characteristics, yield force, and sound production. Skull vibration, jaw-muscle activity, and jaw movement were measured while the subjects chewed and swallowed the food. Auditory and/or visual masking did not have a significant effect on skull vibration, muscle activity, and number of chewing cycles until swallowing. However, auditory and/or visual masking significantly increased the chewing cycle duration, but only for the participants who started the experiments with auditory and/or visual masking. The other participants were not influenced by masking. The memory of the unmodified stimuli helped these subjects to maintain their habitual chewing rate in later trials.

van der Bilt A; Pocztaruk RL; Frasca LC; van der Glas HW; Abbink JH

2011-12-01

34

The influence of auditory and visual information on the neuromuscular control of chewing crispy food.  

Science.gov (United States)

The influence of auditory and/or visual information on the neuromuscular control of chewing a crispy food was investigated. Participants chewed biscuits of three different levels of crispness under four experimental conditions: no masking, auditory masking, visual masking, and auditory plus visual masking. The order of the four masking condition blocks was randomized. The sound of chewing was masked by loud sounds on a headphone, and visual masking of the food was achieved by closing the eyes. Mechanical tests were performed on the biscuits to determine their characteristics, yield force, and sound production. Skull vibration, jaw-muscle activity, and jaw movement were measured while the subjects chewed and swallowed the food. Auditory and/or visual masking did not have a significant effect on skull vibration, muscle activity, and number of chewing cycles until swallowing. However, auditory and/or visual masking significantly increased the chewing cycle duration, but only for the participants who started the experiments with auditory and/or visual masking. The other participants were not influenced by masking. The memory of the unmodified stimuli helped these subjects to maintain their habitual chewing rate in later trials. PMID:22112027

van der Bilt, Andries; Pocztaruk, Rafael L; Frasca, Luis C F; van der Glas, Hilbert W; Abbink, Jan H

2011-12-01

35

Generation of neuromuscular specificity in Drosophila: novel mechanisms revealed by new technologies.  

UK PubMed Central (United Kingdom)

The Drosophila larval neuromuscular system is one of the best-characterized model systems for axon targeting. In each abdominal hemisegment, only 36 identified motor neurons form synaptic connections with just 30 target muscles in a highly specific and stereotypic manner. Studies in the 1990s identified several cell-surface and secreted proteins that are expressed in specific muscles and contribute to target specificity. Emerging evidence suggests that target selection is determined not only by attraction to the target cells but also by exclusion from non-target cells. Proteins with leucine-rich repeats (LRR proteins) appear to be a major molecular family of proteins responsible for the targeting. While the demonstrated roles of the target-derived cues point to active recognition by presynaptic motor neurons, postsynaptic muscles also reach out and recognize specific motor neurons by sending out cellular protrusions called myopodia. Simultaneous live imaging of myopodia and growth cones has revealed that local and mutual recognition at the tip of myopodia is critical for selective synapse formation. A large number of candidate target cues have been identified on a single muscle, suggesting that target specificity is determined by the partially redundant and combinatorial function of multiple cues. Analyses of the seemingly simple neuromuscular system in Drosophila have revealed an unexpected complexity in the mechanisms of axon targeting.

Nose A

2012-01-01

36

Neuromuscular electrical stimulation for stroke rehabilitation: Is spinal plasticity a possible mechanism associated with diminished spasticity?  

UK PubMed Central (United Kingdom)

Although the specific pathophysiological mechanisms underlying the development of spasticity are not fully understood, a large amount of evidence suggests that abnormalities in spinal pathways regulating the stretch reflex may contribute to the hypertonia and hyperreflexia that characterize spasticity. It is quite interesting that neuromuscular electrical stimulation (NMES) has been reported as an efficient treatment for reducing spasticity after stroke while other reports have shown that it promotes neuroplasticity in healthy subjects. The hypothesis addressed in this paper is that plastic effects within some spinal cord pathways may be a possible mechanism associated with the NMES-induced improvements in spasticity. If the hypothesis is proven corrected, the association between plasticity within specific spinal pathways and NMES-induced improvements in spasticity may be used to guide the choice of stimulation parameters to be used in NMES-based stroke rehabilitation protocols.

Motta-Oishi AA; Magalhães FH; Mícolis de Azevedo F

2013-08-01

37

Doenças neuromusculares/ Neuromuscular disorders  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese Objetivo: apresentar os dados essenciais para o diagnóstico diferencial entre as principais doenças neuromusculares, denominação genérica sob a qual agrupam-se diferentes afecções, decorrentes do acometimento primário da unidade motora (motoneurônio medular, raiz nervosa, nervo periférico, junção mioneural e músculo). Fontes dos dados: os aspectos clínicos fundamentais para estabelecer o diagnóstico diferencial entre as diferentes doenças neuromusculares, (more) bem como entre estas e as causas de hipotonia muscular secundária ao comprometimento do sistema nervoso central ou a doenças sistêmicas não-neurológicas, são enfatizados, com base na experiência clínica vinda do atendimento a crianças com doenças neuromusculares durante os últimos 12 anos, no ambulatório de doenças neuromusculares do Hospital das Clínicas da Faculdade de Medicina, da Universidade de São Paulo. A revisão bibliográfica foi efetuada através do Medline e do periódico Neuromuscular Disorders, publicação oficial da World Muscle Society. Síntese dos dados: nas crianças, a maior parte destas afecções é geneticamente determinada, sendo as mais comuns a distrofia muscular progressiva ligada ao sexo, de Duchenne, a amiotrofia espinal infantil, a distrofia muscular congênita, a distrofia miotônica de Steinert, e as miopatias congênitas, estruturais e não estruturais. Polineuropatias hereditárias, síndrome miastênica congênita e miopatias metabólicas são menos comuns, porém mostram correlação geno-fenotípica cada vez mais precisa. Conclusões: na década passada, inúmeros avanços da genética molecular facilitaram imensamente o diagnóstico e o aconselhamento genético das doenças neuromusculares mais comuns das crianças, inclusive possibilitando diagnóstico fetal e, adicionalmente, vieram permitir melhor caracterização fenotípica e classificação mais objetiva. Abstract in english Objective: to discuss the most important aspects for performing a differential diagnosis among the main neuromuscular disorders in children, that include the diseases affecting the motor unity, i.e. spinal motor neurons, peripheral nerves, neuromuscular junction and muscular fibers. Sources: the review of the clinical aspects that should be considered for a prompt differential diagnosis among several neuromuscular disorders as well as between those and the main causes of (more) secondary muscular hypotonia due to central nervous system or systemic disturbances is based on the clinical experience acquired along the last 12 years in following-up children with Neuromuscular Disorders attended at the outpatient Service of Neuromuscular Disorders at the Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo. In addition, it is based on Medline and on the review of the most recent numbers of Neuromuscular Disorders, the official journal of the World Muscle Society. Summary of the findings: most of neuromuscular disorders are genetic conditions in children and the most common of them are X-linked Progressive Muscular Dystrophy of Duchenne, Spinal Muscular Atrophy, Congenital Muscular Dystrophy, Myotonic Dystrophy and Congenital Myopathies. Conclusions: due to the phenomenal development in human molecular genetics the pathogenesis of several neuromuscular disorders in children has been clarified over the last decade. Nowadays many new diagnostic methods, including techniques of fetal diagnosis, and a more objective genotype-phenotype correlation as well as classification are available.

Reed, Umbertina C.

2002-08-01

38

Neuromuscular scoliosis.  

UK PubMed Central (United Kingdom)

Scoliosis is a common deformity in many types of neuromuscular disease. Severe spinal curvature can cause difficulty in sitting. Conservative and surgical treatment of neuromuscular scoliosis differs from idiopathic scoliosis, being more complex and with a higher complications rate. Non-surgical measures rarely fully control progressive scoliosis, but aim to prevent spinal deformities secondary to muscular hypotonia or contracture. Twenty-four hour bracing should be adjusted throughout growth, and may induce functional impairment and loss of independence. Corrective surgery requires multidisciplinary management and perioperative screening. Pelvic obliquity is commonly associated with neuromuscular scoliosis, making sitting difficult: correction needs to be considered during surgical planning. The goal of surgical correction is to obtain and maintain a well-balanced spine above a well-positioned pelvis. Preoperative multidisciplinary assessment enables potential problems of terrain to be anticipated. Respiratory function investigation will guide possible non-invasive perioperative ventilation. Nutritional and psychosocial assessment should also be incorporated in this preparation, as should overall postoperative care. Implementing this overall strategic planning can achieve a good surgical and functional result in the vast majority of cases.

Vialle R; Thévenin-Lemoine C; Mary P

2013-02-01

39

Effect of orthoses on changes in neuromuscular control and aerobic cost of a 1-h run.  

UK PubMed Central (United Kingdom)

PURPOSE: The study's purpose was to determine the effect of foot orthoses on neuromuscular control and the aerobic cost of running. METHODS: Twelve recreational athletes ran for 1 h on a treadmill at a constant velocity (i.e., 10% higher than their first ventilatory threshold) with and without custom-molded foot orthoses, in a counterbalanced order. Surface EMG activity of five lower limb muscles, together with oxygen consumption and HR, was recorded at 8-min intervals, starting after 2 min, during the run. A series of neuromuscular tests including voluntary and electrically evoked contractions of the ankle plantar flexors was performed before and after running. RESULTS: Peroneus longus root mean square amplitude decreased with time, independently of the condition (-18.9%, P < 0.01). Lower root mean square signal amplitude for vastus medialis (-13.3%, P < 0.02) and gastrocnemius medialis (-10.7%, P < 0.05), combined with increased peroneus longus burst duration (+14.7%, P < 0.05), occurred when running with orthoses. There was no main effect of the condition for oxygen consumption (P > 0.05), whereas HR was significantly lowered while wearing foot orthoses (-3%, P < 0.02). Maximal strength capacity (-9%, P < 0.01), normalized EMG activity (-17%, P < 0.001), and peak twitch torque (-14%, P < 0.01) declined from before to after exercise, independently of the condition. Smaller fatigue-induced decrements in the rate of torque development within the first 200 ms (-6% vs -33%, P < 0.01) were reported after running with foot orthoses. CONCLUSIONS: Wearing foot orthoses alters neuromuscular control during a submaximal 1-h treadmill run and partly protects from the resulting fatigue-induced reductions in rapid force development characteristics of the plantar flexors. However, these changes may be too small to alter the aerobic cost of running.

Kelly LA; Girard O; Racinais S

2011-12-01

40

Postoperative effects of neuromuscular exercise prior to hip or knee arthroplasty: a randomised controlled trial.  

Science.gov (United States)

OBJECTIVE: To investigate the postoperative efficacy of a supervised programme of neuromuscular exercise prior to hip or knee arthroplasty. METHODS: In this assessor-blinded randomised controlled trial, we included 165 patients scheduled for hip or knee arthroplasty due to severe osteoarthritis (OA). An 8-week preoperative neuromuscular supervised exercise programme was delivered twice a week for 1 h as adjunct treatment to the standard arthroplasty procedure and compared with the standard arthroplasty procedure alone. The primary outcome was self-reported physical function measured on the activities of daily living (ADL) subscale in the Hip disability and Osteoarthritis Outcome Score (HOOS) and the Knee injury and Osteoarthritis Outcome Score (KOOS) questionnaires for patients with hip and knee OA, respectively. Primary endpoint was 3 months after surgery. RESULTS: 165 patients randomised to the two groups were on average 67±8 years, 84 (51%) had hip OA and 92 (56%) were women. 153 patients (93%) underwent planned surgery and were evaluated postoperatively. There was no statistically significant difference in effects between hip or knee patients (p=0.7370). Three months postoperatively, no difference was found between groups for ADL (4.4, 95% CI -0.8 to 9.5) or pain (4.5, 95% CI -0.8 to 9.9). However, there was a statistically significant difference indicating an effect of exercise over the entire period (baseline to 3-months postoperatively) (p=0.0029). CONCLUSIONS: Eight weeks of supervised neuromuscular exercise prior to total joint arthroplasty (TJA) of the hip or knee did not confer additional benefits 3 months postoperatively compared with TJA alone. However, the intervention group experienced a statistically significant short-term benefit in ADL and pain, suggesting an earlier onset of postoperative recovery. TRIAL REGISTRATION: ClinicalTrials NCT01003756. PMID:23661494

Villadsen, Allan; Overgaard, Søren; Holsgaard-Larsen, Anders; Christensen, Robin; Roos, Ewa M

2013-05-01

 
 
 
 
41

Postoperative effects of neuromuscular exercise prior to hip or knee arthroplasty : a randomised controlled trial  

DEFF Research Database (Denmark)

OBJECTIVE: To investigate the postoperative efficacy of a supervised programme of neuromuscular exercise prior to hip or knee arthroplasty. METHODS: In this assessor-blinded randomised controlled trial, we included 165 patients scheduled for hip or knee arthroplasty due to severe osteoarthritis (OA). An 8-week preoperative neuromuscular supervised exercise programme was delivered twice a week for 1 h as adjunct treatment to the standard arthroplasty procedure and compared with the standard arthroplasty procedure alone. The primary outcome was self-reported physical function measured on the activities of daily living (ADL) subscale in the Hip disability and Osteoarthritis Outcome Score (HOOS) and the Knee injury and Osteoarthritis Outcome Score (KOOS) questionnaires for patients with hip and knee OA, respectively. Primary endpoint was 3 months after surgery. RESULTS: 165 patients randomised to the two groups were on average 67±8 years, 84 (51%) had hip OA and 92 (56%) were women. 153 patients (93%) underwent planned surgery and were evaluated postoperatively. There was no statistically significant difference in effects between hip or knee patients (p=0.7370). Three months postoperatively, no difference was found between groups for ADL (4.4, 95% CI -0.8 to 9.5) or pain (4.5, 95% CI -0.8 to 9.9). However, there was a statistically significant difference indicating an effect of exercise over the entire period (baseline to 3-months postoperatively) (p=0.0029). CONCLUSIONS: Eight weeks of supervised neuromuscular exercise prior to total joint arthroplasty (TJA) of the hip or knee did not confer additional benefits 3 months postoperatively compared with TJA alone. However, the intervention group experienced a statistically significant short-term benefit in ADL and pain, suggesting an earlier onset of postoperative recovery. TRIAL REGISTRATION: ClinicalTrials NCT01003756.

Villadsen, Allan; Overgaard, SØren

2013-01-01

42

Postoperative effects of neuromuscular exercise prior to hip or knee arthroplasty: a randomised controlled trial.  

UK PubMed Central (United Kingdom)

OBJECTIVE: To investigate the postoperative efficacy of a supervised programme of neuromuscular exercise prior to hip or knee arthroplasty. METHODS: In this assessor-blinded randomised controlled trial, we included 165 patients scheduled for hip or knee arthroplasty due to severe osteoarthritis (OA). An 8-week preoperative neuromuscular supervised exercise programme was delivered twice a week for 1 h as adjunct treatment to the standard arthroplasty procedure and compared with the standard arthroplasty procedure alone. The primary outcome was self-reported physical function measured on the activities of daily living (ADL) subscale in the Hip disability and Osteoarthritis Outcome Score (HOOS) and the Knee injury and Osteoarthritis Outcome Score (KOOS) questionnaires for patients with hip and knee OA, respectively. Primary endpoint was 3 months after surgery. RESULTS: 165 patients randomised to the two groups were on average 67±8 years, 84 (51%) had hip OA and 92 (56%) were women. 153 patients (93%) underwent planned surgery and were evaluated postoperatively. There was no statistically significant difference in effects between hip or knee patients (p=0.7370). Three months postoperatively, no difference was found between groups for ADL (4.4, 95% CI -0.8 to 9.5) or pain (4.5, 95% CI -0.8 to 9.9). However, there was a statistically significant difference indicating an effect of exercise over the entire period (baseline to 3-months postoperatively) (p=0.0029). CONCLUSIONS: Eight weeks of supervised neuromuscular exercise prior to total joint arthroplasty (TJA) of the hip or knee did not confer additional benefits 3 months postoperatively compared with TJA alone. However, the intervention group experienced a statistically significant short-term benefit in ADL and pain, suggesting an earlier onset of postoperative recovery. TRIAL REGISTRATION: ClinicalTrials NCT01003756.

Villadsen A; Overgaard S; Holsgaard-Larsen A; Christensen R; Roos EM

2013-05-01

43

A holistic view of adenosine in the control of intestinal neuromuscular functions: the enteric 'purinome' concept  

Science.gov (United States)

Adenosine is involved in the modulation of enteric neuromuscular functions, operating a fine tuning of smooth muscle contractility, peristaltic reflex and transit. In this issue of the BJP, Zizzo et al. report novel findings on the expression of adenosine receptors in mouse duodenum, extending our knowledge of their involvement in the control of spontaneous and neurogenic intestinal motility. In this study, particular attention was paid to the differential activation of adenosine receptors, as a result of their interplay with regulatory systems, modulating the availability of endogenous adenosine in a compartmentalised manner. This evidence will contribute to the holistic evaluation of the role played by adenosine in the regulation of intestinal motility, in accordance with the novel concept of the enteric ‘purinome’. This commentary discusses the role of the ‘purinome’ in the modulation of enteric neuromuscular activity, pointing out its involvement in the intestinal neuroplasticity associated with bowel dysmotility. LINKED ARTICLE This article is a commentary on Zizzo et al., pp. 1580–1589 of this issue. To view this paper visit http://dx.doi.org/10.1111/j.1476-5381.2011.01498.x

Antonioli, Luca; Fornai, Matteo; Colucci, Rocchina; Tuccori, Marco; Blandizzi, Corrado

2011-01-01

44

Estimulação elétrica neuromuscular e o alongamento passivo manual na recuperação das propriedades mecânicas do músculo gastrocnêmio imobilizado/ Neuromuscular electric stimulation and manual passive stretching when recovering mechanical properties of immobilized gastrocnemius muscles  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese Avaliamos a influência da imobilização, remobilização livre, remobilização com alongamento passivo manual, remobilização com estimulação elétrica neuromuscular (NMES) e remobilização por NMES e alongamento passivo manual associados sobre algumas propriedades mecânicas do músculo gastrocnêmio de ratas. Foram avaliadas 60 ratas divididas em seis grupos.Um destes grupos foi usado como controle. Todos os outros grupos tiveram o membro posterior direito imobil (more) izado por 14 dias consecutivos. Destes grupos um foi imobilizado e em seguida avaliado, um foi liberado da imobilização e permaneceu nas gaiolas plásticas por 10 dias, outro foi submetido a técnica de alongamento passivo manual por 10 dias consecutivos, outro foi submetido a NMES por 10 dias consecutivos e o último foi submetido a NMES somado ao alongamento passivo manual por 10 dias consecutivos. Observamos que a imobilização reduziu os valores das propriedades mecânicas avaliadas no músculo. A remobilização livre não restabeleceu nenhuma das propriedades avaliadas. A remobilização por alongamento passivo manual devolveu ao músculo as propriedades de alongamento no limite de proporcionalidade, rigidez e resiliência. A remobilização estimulada por NMES restabeleceu todas as propriedades estudadas. A remobilização por NMES somada ao alongamento passivo restabeleceu as propriedades mecânicas de alongamento no limite máximo e de proporcionalidade e rigidez. Abstract in english We evaluated the influence of immobilization, free remobilization, remobilization with manual passive stretching, remobilization with neuromuscular electric stimulation (NMES) and remobilization with electric stimulation and associated passive stretching on some mechanical properties of the gastrocnemius muscle of female rats. Sixty female rats were assessed, being distributed into 6 experimental groups. One of these groups served as control. The animals of the five remai (more) ning groups had their right posterior limb immobilized for 14 consecutive days. From the five groups, one was sacrificed right after the immobilization period, a second group was released from immobilization, a third was submitted to the manual passive stretching technique for 10 consecutive days, a fourth was submitted to NMES for 10 consecutive days and the last one was submitted to NMES and manual passive stretching for 10 consecutive days. We found that the immobilization caused a significant reduction of the mechanical properties values evaluated on the muscle. The free remobilization could not reestablish any of the properties. The remobilization by manual passive stretching restored the mechanical properties of stretching at the proportionality limit, stiffness and resilience. The remobilization stimulated by NMES reestablished all of studied properties. The remobilization by electric stimulation and passive stretching reestablished the mechanical properties of stretching at the maximum limit, proportionality limit, and stiffness.

Carvalho, Leonardo César; Shimano, Antonio Carlos; Picado, Celso Hermínio Ferraz

2008-01-01

45

Use of a neuromuscular electrical stimulation device for facial muscle toning: a randomized, controlled trial.  

UK PubMed Central (United Kingdom)

BACKGROUND: Age-related loss of muscle mass contributes to aging of the human face. AIMS: To evaluate the effects of a neuromuscular electrical stimulation (NMES) device on facial muscle tone and signs of facial aging in healthy women. PATIENTS/METHODS: One hundred and eight healthy women (mean age 43.7, range 32 to 58-45 years) participated in this randomized, controlled, partially blinded study. Participants were randomized to 12 weeks' treatment with the NMES facial device (20 min/day, 5 days/week) or to a nonintervention control group. Participants could not alter fitness, diet or facial care routines during the study. Assessments included psychometric evaluations of facial appearance and assessor-blinded ultrasound measurements of the thickness of the zygomatic major muscle. RESULTS: Mean muscle thickness increased vs. baseline in the NMES group (18.6%) but not the control group. Between-group differences were significant at 6 and 12 weeks (P = 0.05 and P = 0.0001). NMES users reported subjective improvements in facial attributes. The control group did not. In an overall evaluation, ?80% of NMES users reported improved firmness, tone and lift vs. <5% of the control group (P < 0.001). CONCLUSIONS: A 12-week course of facial NMES was associated with increased thickness of the zygomatic major muscle and subjective improvements in facial attributes.

Kavanagh S; Newell J; Hennessy M; Sadick N

2012-12-01

46

Center of Mass Acceleration Feedback Control for Standing by Functional Neuromuscular Stimulation - a Simulation Study  

Science.gov (United States)

The potential efficacy of total body center of mass (COM) acceleration for feedback control of standing balance by functional neuromuscular stimulation (FNS) following spinal cord injury (SCI) was investigated. COM acceleration may be a viable alternative to conventional joint kinematics due to its rapid responsiveness, focal representation of COM dynamics, and ease of measurement. A computational procedure was developed using an anatomically-realistic, three-dimensional, bipedal biomechanical model to determine optimal patterns of muscle excitations to produce targeted effects upon COM acceleration from erect stance. The procedure was verified with electromyographic data collected from standing able-bodied subjects undergoing systematic perturbations. Using 16 muscle groups targeted by existing implantable neuroprostheses, data were generated to train an artificial neural network (ANN)-based controller in simulation. During forward simulations, proportional feedback of COM acceleration drove the ANN to produce muscle excitation patterns countering the effects of applied perturbations. Feedback gains were optimized to minimize upper extremity (UE) loading required to stabilize against disturbances. Compared to the clinical case of maximum constant excitation, the controller reduced UE loading by 43% in resisting external perturbations and by 51% during simulated one-arm reaching. Future work includes performance assessment against expected measurement errors and developing user-specific control systems.

Audu, Musa L.; Kirsch, Robert F.; Triolo, Ronald J.

2013-01-01

47

Center of mass acceleration feedback control for standing by functional neuromuscular stimulation: a simulation study.  

Science.gov (United States)

The potential efficacy of total body center of mass (COM) acceleration for feedback control of standing balance by functional neuromuscular stimulation (FNS) following spinal cord injury (SCI) was investigated. COM acceleration may be a viable alternative to conventional joint kinematics because of its rapid responsiveness, focal representation of COM dynamics, and ease of measurement. A computational procedure was developed using an anatomically realistic, three-dimensional, bipedal biomechanical model to determine optimal patterns of muscle excitations to produce targeted effects upon COM acceleration from erect stance. The procedure was verified with electromyographic data collected from standing nondisabled subjects undergoing systematic perturbations. Using 16 muscle groups targeted by existing implantable neuroprostheses, we generated data to train an artificial neural network (ANN)-based controller in simulation. During forward simulations, proportional feedback of COM acceleration drove the ANN to produce muscle excitation patterns countering the effects of applied perturbations. Feedback gains were optimized to minimize upper-limb (UL) loading required to stabilize against disturbances. Compared with the clinical case of maximum constant excitation, the controller reduced UL loading by 43% in resisting external perturbations and by 51% during simulated one-arm reaching. Future work includes performance assessment against expected measurement errors and development of user-specific control systems. PMID:22773529

Nataraj, Raviraj; Audu, Musa L; Kirsch, Robert F; Triolo, Ronald J

2012-01-01

48

Center of mass acceleration feedback control for standing by functional neuromuscular stimulation: a simulation study.  

UK PubMed Central (United Kingdom)

The potential efficacy of total body center of mass (COM) acceleration for feedback control of standing balance by functional neuromuscular stimulation (FNS) following spinal cord injury (SCI) was investigated. COM acceleration may be a viable alternative to conventional joint kinematics because of its rapid responsiveness, focal representation of COM dynamics, and ease of measurement. A computational procedure was developed using an anatomically realistic, three-dimensional, bipedal biomechanical model to determine optimal patterns of muscle excitations to produce targeted effects upon COM acceleration from erect stance. The procedure was verified with electromyographic data collected from standing nondisabled subjects undergoing systematic perturbations. Using 16 muscle groups targeted by existing implantable neuroprostheses, we generated data to train an artificial neural network (ANN)-based controller in simulation. During forward simulations, proportional feedback of COM acceleration drove the ANN to produce muscle excitation patterns countering the effects of applied perturbations. Feedback gains were optimized to minimize upper-limb (UL) loading required to stabilize against disturbances. Compared with the clinical case of maximum constant excitation, the controller reduced UL loading by 43% in resisting external perturbations and by 51% during simulated one-arm reaching. Future work includes performance assessment against expected measurement errors and development of user-specific control systems.

Nataraj R; Audu ML; Kirsch RF; Triolo RJ

2012-01-01

49

EEG controlled neuromuscular electrical stimulation of the upper limb for stroke patients  

Science.gov (United States)

This paper describes the Brain Computer Interface (BCI) system and the experiments to allow post-acute (<3 months) stroke patients to use electroencephalogram (EEG) to trigger neuromuscular electrical stimulation (NMES)-assisted extension of the wrist/fingers, which are essential pre-requisites for useful hand function. EEG was recorded while subjects performed motor imagery of their paretic limb, and then analyzed to determine the optimal frequency range within the mu-rhythm, with the greatest attenuation. Aided by visual feedback, subjects then trained to regulate their mu-rhythm EEG to operate the BCI to trigger NMES of the wrist/finger. 6 post-acute stroke patients successfully completed the training, with 4 able to learn to control and use the BCI to initiate NMES. This result is consistent with the reported BCI literacy rate of healthy subjects. Thereafter, without the loss of generality, the controller of the NMES is developed and is based on a model of the upper limb muscle (biceps/triceps) groups to determine the intensity of NMES required to flex or extend the forearm by a specific angle. The muscle model is based on a phenomenological approach, with parameters that are easily measured and conveniently implemented.

Tan, Hock Guan; Shee, Cheng Yap; Kong, Keng He; Guan, Cuntai; Ang, Wei Tech

2011-03-01

50

Persons with unilateral lower-limb amputation have altered and asymmetric trunk mechanical and neuromuscular behaviors estimated using multidirectional trunk perturbations.  

UK PubMed Central (United Kingdom)

Among persons with unilateral lower-limb amputation (LLA), proximal compensations and preferential use of the sound limb during gait and movement may lead to chronic alterations and/or asymmetries in trunk mechanical and neuromuscular behaviors. Trunk stiffness, the magnitude and timing of maximum reflex force, and EMG reflex delays of superficial trunk muscles, were estimated here using multidirectional (anteriorly- and laterally-directed) position-controlled horizontal trunk perturbations (±5mm, applied at T8) with the pelvis immobilized. Alterations and asymmetries in these trunk behaviors were quantified and compared among eight males with unilateral LLA, and eight male non-amputation controls. During anteriorly-directed perturbations, trunk stiffness and maximum reflex force were 24% and 23% lower, respectively, among participants with LLA compared to non-amputation controls, and the timing of maximum reflex force was 8% later. During lateral perturbations, trunk stiffness and maximum reflex force were also significantly lower among participants with LLA, by 22% and 27%, respectively. Bilateral asymmetries were present in trunk stiffness and the timing of maximum reflex force among persons with LLA. Specifically, trunk stiffness was 20% lower and timing of maximum reflex force was 9% later during perturbations involving spinal tissues and muscles ipsilateral to the side of amputation. Reduced and asymmetric trunk mechanical and neuromuscular behaviors may suggest a condition of reduced trunk stability among individuals with LLA, which could be due to repeated exposure to altered and asymmetric gait and movement and/or compensatory muscle recruitment in response to lost or altered musculature subsequent to LLA.

Hendershot BD; Bazrgari B; Nussbaum MA

2013-07-01

51

[Mechanism of the development of neuromuscular disorders in Itsenko-Cushing disease  

UK PubMed Central (United Kingdom)

The results of electromyographic studies indicate that the affection of the neuromuscular system is seen in all the patients with Icenko-Cushing's disease. Changes in different indices of the electromyogram (EMG), i.e. denervation activity, a character of the summary EMG alteration, mean duration of the motor unit action potentials (MUAP), the number of polyphase action potentials, their amplitude and the MUAP synchronization in different spheres indicate a neurogenic character of this affection. It was shown that both denervation and reinnervation processes are more pronounced in the foot muscles than in the hand ones. The denervation process is seemed to be primarily developed in the foot muscles, followed by the hand musculature injury. Therefore, the changes in several EMG parameters may be seen during several stages of the disease in some muscles and not to be observed in the others.

Agafonov BV; Lahutina TS; Deianova AF

1982-11-01

52

Role of temperature in quanta mechanisms of facilitation in the frog neuromuscular junction.  

UK PubMed Central (United Kingdom)

The results of computer simulations on the Double Barrier Synapse (DBS) model are presented which quantify the relationship between the synapse parameters and the quanta transfer process. The DBS model is applicable to a variety of states of synaptic activity, and by changing the synapse parameters it is possible to simulate various conditions of quanta transmission. The influence of the bathing solution temperature change on the synaptic parameters under different conditions of transmitter release in the frog neuromuscular junction is investigated. Simulations demonstrate that several synaptic parameters, including the parameters of the presynaptic membrane, are not affected by the temperature change. It is shown that a stimulation frequency exists at which the steady-state level of facilitation during a long train of stimuli is the same for a wide range of temperatures.

Yeghiazarian L; Kaiser M

1998-07-01

53

No effect on performance tests from a neuromuscular warm-up programme in youth female football: a randomised controlled trial.  

UK PubMed Central (United Kingdom)

PURPOSE: The objective of the present randomised controlled trial was to study the effect of a neuromuscular warm-up programme on performance tests in youth female football. METHODS: Four youth female football teams with players aged 12-16 years were randomised into an intervention group and control group. The intervention was a 15-min neuromuscular warm-up programme carried out twice a week during the 11-week study period. Baseline and follow-up measurements of performance were made indoors and included the star excursion balance test, a countermovement jump test, a triple-hop for distance test, a modified Illinois agility test, and 10- and 20-m sprint tests. RESULTS: Fifty-two players (intervention 28; control 24) took part in baseline measurements, and after dropout, 41 players (intervention 23; control 18) were included for analysis. Minor positive changes were seen in the control group compared to the intervention group for a sub-score of the star excursion balance test (P < 0.05) and in the modified Illinois agility test (P < 0.05). No improvement was seen in the intervention group from baseline to follow-up. CONCLUSIONS: The study showed that a neuromuscular warm-up programme carried out during 11 weeks did not improve performance in youth female football. This could indicate that the programme does not contain sufficient stimulus to improve performance. A low player attendance at training sessions, and low specificity between exercises in the warm-up programme and the evaluated performance tests may also contribute to the lack of effect. LEVEL OF EVIDENCE: I.

Lindblom H; Waldén M; Hägglund M

2012-10-01

54

Efeitos da estimulação elétrica neuromuscular durante a imobilização nas propriedades mecânicas do músculo esquelético Efectos de la estimulación eléctrica neuromuscular durante la inmovilización en las propiedades mecánicas del músculo esquelético Effects of neuromuscular electric stimulation during immobilization in the mechanical properties of the skeletal muscle  

Directory of Open Access Journals (Sweden)

Full Text Available A estimulação elétrica neuromuscular (EENM) é um importante recurso utilizado em medicina esportiva para acelerar processos de recuperação. O objetivo deste estudo foi analisar os efeitos da EENM durante a imobilização do músculo gastrocnêmio, em posições de alongamento (LP) e encurtamento (SP). Para tanto, 60 ratas fêmeas jovens Wistar foram distribuídas em seis grupos e acompanhadas durante sete dias: controle (C), eletroestimuladas (EE), imobilizadas em encurtamento (ISP), imobilizadas em alongamento (ILP), imobilizadas em encurtamento e eletroestimuladas (ISP + EE) e imobilizadas em alongamento e eletroestimuladas (ILP + EE). Para a imobilização, o membro posterior direito foi envolvido por uma malha tubular e ataduras de algodão juntamente à atadura gessada. A EENM foi utilizada com freqüência de 50Hz, 10 minutos por dia, totalizando 20 contrações em cada sessão. Após sete dias os animais foram submetidos a eutanásia e os músculos gastrocnêmios retirados para a realização do ensaio mecânico de tração em uma máquina universal de ensaios (EMIC®). A partir dos gráficos carga versus alongamento, foram calculadas as seguintes propriedades mecânicas: alongamento no limite de proporcionalidade (ALP), carga no limite de proporcionalidade (CLP) e rigidez. As imobilizações SP e LP promoveram reduções significativas (p La estimulación eléctrica neuromuscular (EENM) es un importante recurso utilizado en medicina deportiva para acelerar procesos de recuperación. El objetivo de este estudio ha sido analizar los efectos de la EENM durante la inmovilización del músculo gastrocnemio, en posiciones de alongamiento (LP) y contracción (SP). Para tal fin, 60 ratones hembras jóvenes Wistar fueron distribuidas en seis grupos y monitoreadas durante 7 días: control (C), electro estimuladas (EE), inmovilizadas en contracción (ISP), inmovilizadas en alongamiento (ILP), inmovilizadas en contracción y electro estimuladas (ISP + EE) e inmovilizadas en alongamiento y electro estimuladas (ILP + EE). Para la inmovilización, el miembro posterior derecho fue envuelto por una malla tubular y vendas de algodón en conjunto con vendas de escayola. La EENM fue utilizada con una frecuencia de 50 Hz, 10 minutos por día, totalizando 20 contracciones en cada sesión. Después de 7 días los animales fueron sometidos a eutanasia y los músculos gastrocnemios fueron retirados para la realización del ensayo mecánico de tracción en una máquina universal de ensayos (EMIC®). A partir de los gráficos carga versus alongamiento se calculó las siguientes propiedades mecánicas: alongamiento en el límite de proporcionalidad (ALP), carga en el límite de proporcionalidad (CLP) y rigidez. Las inmovilizaciones SP y LP dieron reducciones significativas (p The neuromuscular electric stimulation (NMES) is an important tool used in sports medicine to accelerate the recovery process. The objective of this study was to analyze the effects of NMES during immobilization of the gastrocnemius muscle, in lengthened (LP) and shortened positions (SP). Sixty young female Wistar rats were distributed into six groups and followed for 7 days: control (C); electric stimulation (ES); immobilized in shortening (ISP); immobilized in lengthening (ILP); immobilized in shortening and electric stimulation (ISP + ES) and immobilized in lengthening and electric stimulation (ILP + ES). For the immobilization, a tubular mesh and cotton rolls together with the plaster were wrapped around the rat's right posterior paw. NMES in a frequency of 50 Hz was used 10 minutes a day, totaling 20 contractions in each session. After 7 days the animals were sacrificed and their gastrocnemius muscles of the right paw were submitted to a mechanical test of traction in a universal test machine (EMIC®). From the load versus elongation curves the following mechanical properties were obtained: elongation in the yield limit (EPL), load in the yield limit (LPL) and stiffness. The SP and LP immobilizations promoted significant reductions (p < 0

João Paulo Chieregato Matheus; Liana Barbaresco Gomide; Juliana Goulart Prata de Oliveira; José Batista Volpon; Antônio Carlos Shimano

2007-01-01

55

Efeitos da estimulação elétrica neuromuscular durante a imobilização nas propriedades mecânicas do músculo esquelético/ Effects of neuromuscular electric stimulation during immobilization in the mechanical properties of the skeletal muscle/ Efectos de la estimulación eléctrica neuromuscular durante la inmovilización en las propiedades mecánicas del músculo esquelético  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese A estimulação elétrica neuromuscular (EENM) é um importante recurso utilizado em medicina esportiva para acelerar processos de recuperação. O objetivo deste estudo foi analisar os efeitos da EENM durante a imobilização do músculo gastrocnêmio, em posições de alongamento (LP) e encurtamento (SP). Para tanto, 60 ratas fêmeas jovens Wistar foram distribuídas em seis grupos e acompanhadas durante sete dias: controle (C), eletroestimuladas (EE), imobilizadas em e (more) ncurtamento (ISP), imobilizadas em alongamento (ILP), imobilizadas em encurtamento e eletroestimuladas (ISP + EE) e imobilizadas em alongamento e eletroestimuladas (ILP + EE). Para a imobilização, o membro posterior direito foi envolvido por uma malha tubular e ataduras de algodão juntamente à atadura gessada. A EENM foi utilizada com freqüência de 50Hz, 10 minutos por dia, totalizando 20 contrações em cada sessão. Após sete dias os animais foram submetidos a eutanásia e os músculos gastrocnêmios retirados para a realização do ensaio mecânico de tração em uma máquina universal de ensaios (EMIC®). A partir dos gráficos carga versus alongamento, foram calculadas as seguintes propriedades mecânicas: alongamento no limite de proporcionalidade (ALP), carga no limite de proporcionalidade (CLP) e rigidez. As imobilizações SP e LP promoveram reduções significativas (p Abstract in spanish La estimulación eléctrica neuromuscular (EENM) es un importante recurso utilizado en medicina deportiva para acelerar procesos de recuperación. El objetivo de este estudio ha sido analizar los efectos de la EENM durante la inmovilización del músculo gastrocnemio, en posiciones de alongamiento (LP) y contracción (SP). Para tal fin, 60 ratones hembras jóvenes Wistar fueron distribuidas en seis grupos y monitoreadas durante 7 días: control (C), electro estimuladas (E (more) E), inmovilizadas en contracción (ISP), inmovilizadas en alongamiento (ILP), inmovilizadas en contracción y electro estimuladas (ISP + EE) e inmovilizadas en alongamiento y electro estimuladas (ILP + EE). Para la inmovilización, el miembro posterior derecho fue envuelto por una malla tubular y vendas de algodón en conjunto con vendas de escayola. La EENM fue utilizada con una frecuencia de 50 Hz, 10 minutos por día, totalizando 20 contracciones en cada sesión. Después de 7 días los animales fueron sometidos a eutanasia y los músculos gastrocnemios fueron retirados para la realización del ensayo mecánico de tracción en una máquina universal de ensayos (EMIC®). A partir de los gráficos carga versus alongamiento se calculó las siguientes propiedades mecánicas: alongamiento en el límite de proporcionalidad (ALP), carga en el límite de proporcionalidad (CLP) y rigidez. Las inmovilizaciones SP y LP dieron reducciones significativas (p Abstract in english The neuromuscular electric stimulation (NMES) is an important tool used in sports medicine to accelerate the recovery process. The objective of this study was to analyze the effects of NMES during immobilization of the gastrocnemius muscle, in lengthened (LP) and shortened positions (SP). Sixty young female Wistar rats were distributed into six groups and followed for 7 days: control (C); electric stimulation (ES); immobilized in shortening (ISP); immobilized in lengtheni (more) ng (ILP); immobilized in shortening and electric stimulation (ISP + ES) and immobilized in lengthening and electric stimulation (ILP + ES). For the immobilization, a tubular mesh and cotton rolls together with the plaster were wrapped around the rat's right posterior paw. NMES in a frequency of 50 Hz was used 10 minutes a day, totaling 20 contractions in each session. After 7 days the animals were sacrificed and their gastrocnemius muscles of the right paw were submitted to a mechanical test of traction in a universal test machine (EMIC®). From the load versus elongation curves the following mechanical properties were obtained: elongation in the yield limit (EPL), load in the yield limit (L

Matheus, João Paulo Chieregato; Gomide, Liana Barbaresco; Oliveira, Juliana Goulart Prata de; Volpon, José Batista; Shimano, Antônio Carlos

2007-02-01

56

Ankles back in randomized controlled trial (ABrCt): braces versus neuromuscular exercises for the secondary prevention of ankle sprains. Design of a randomised controlled trial  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Ankle sprains are the most common sports and physical activity related injury. There is extensive evidence that there is a twofold increased risk for injury recurrence for at least one year post injury. In up to 50% of all cases recurrences result in disability and lead to chronic pain or instability, requiring prolonged medical care. Therefore ankle sprain recurrence prevention in athletes is essential. This RCT evaluates the effect of the combined use of braces and neuromuscular training (e.g. proprioceptive training/sensorimotor training/balance training) against the individual use of either braces or neuromuscular training alone on ankle sprain recurrences, when applied to individual athletes after usual care. Methods/Design This study was designed as three way randomized controlled trial with one year follow-up. Healthy individuals between 12 and 70 years of age, who were actively participating in sports and who had sustained a lateral ankle sprain in the two months prior to inclusion, were eligible for inclusion. After subjects had finished ankle sprain treatment by means of usual care, they were randomised to any of the three study groups. Subjects in group 1 received an eight week neuromuscular training program, subjects in group 2 received a sports brace to be worn during all sports activities for the duration of one year, and group 3 received a combination of the neuromuscular training program and a sports brace to be worn during all sports activities for the duration of eight weeks. Outcomes were assessed at baseline and every month for 12 months therafter. The primary outcome measure was incidence of ankle sprain recurrences. Secondary outcome measures included the direct and indirect costs of recurrent injury, the severity of recurrent injury, and the residual complaints during and after the intervention. Discussion The ABrCt is the first randomized controlled trial to directly compare the secondary preventive effect of the combined use of braces and neuromuscular training, against the use of either braces or neuromuscular training as separate secondary preventive measures. This study expects to identify the most effective and cost-efficient secondary preventive measure for ankle sprains. The study results could lead to changes in the clinical guidelines on the prevention of ankle sprains, and they will become available in 2012. Trial registration Netherlands Trial Register (NTR): NTR2157

Janssen Kasper W; van Mechelen Willem; Verhagen Evert ALM

2011-01-01

57

Neuromuscular control adaptations in elite athletes: the case of top level karateka.  

UK PubMed Central (United Kingdom)

This paper aimed at investigating the neuromuscular response of knee flexor and extensor muscles in elite karateka and karate amateurs (Amateurs) during isokinetic knee flexion/extensions and during the execution of a front kick (FK). Surface electromyograms (sEMG) were recorded from the right vastus lateralis (VL) and biceps femoris (BF) muscles with a four-array electrode during maximal isometric knee flexion and extension (maximal voluntary contraction), during isokinetic contractions (30 degrees , 90 degrees , 180 degrees , 270 degrees , 340 degrees , 400 degrees /s), and during the FK. The level of VL and BF agonist (ago) and antagonist (ant) activation during the isokinetic and FK protocols was quantified through normalized sEMG root mean square value (%RMS(ago/ant-ISOK/FK)). VL and BF average muscle fiber conduction velocity (CV) was computed for isokinetic and FK. Isokinetic flexion and extension torques and knee angular velocity during FK were also assessed. Analysis of variance was used to test the effect of group, angular velocity, and task on the assessed variables (P < 0.05). Elite karateka showed higher isokinetic knee flexion torque when compared with Amateurs. For all angular velocities, VL and BF %RMS(ant-isokinetic) were lower in elite karateka, while their BF-CV(isokinetic) BF-CV(front kick) and BF %RMS(ant-front kick) values were higher. For VL and BF, %RMS(ago-front kick) was lower than %RMS(ago-isokinetic) in both groups. Elite karateka demonstrated a typical neuromuscular activation strategy that seems task and skill level dependent. Knee flexion torque and CV results suggest the presence of an improved ability of elite karateka to recruit fast MUs as a part of training induced neuromuscular adaptation.

Sbriccoli P; Camomilla V; Di Mario A; Quinzi F; Figura F; Felici F

2010-04-01

58

Tetracyclines and Neuromuscular Disorders  

Science.gov (United States)

Tetracyclines are a class of antibiotics which could act as neuroprotective molecules in several neurological disorders, such as Huntington disease, Parkinson disease, stroke and multiple sclerosis. The main biological effects of tetracyclines are the inhibition of microglial activation, the attenuation of apoptosis and the suppression of reactive oxygen species production. The anti-apoptotic effect of tetracyclines involves the mitochondrion, and the major target for neuroprotective effects of tetracyclines lies within the complex network that links mitochondria, oxidative stress and apoptosis. Neuromuscular disorders are due to dysfunction of motor neurons, peripheral nerves, neuromuscular junction, or skeletal muscle itself. Animal studies have shown that minocycline could play neuroprotective effects in amyotrophic lateral sclerosis, but these positive findings have not been replicated in patients. Other neuromuscular disorders which tetracyclines may benefit are Guillain-Barré syndrome and other neuropathies, muscular dystrophies and mitochondrial disorders. However, well-designed double-blind controlled trials are still needed. Further studies are strongly needed to establish the most appropriate timing and dosage, as well as the indications for which tetracyclines could be effective and safe. Here, we review the neuroprotective effects of tetracyclines in animal models, the clinical studies in humans, and we focus on their potential application in patients with neuromuscular disorders.

Orsucci, Daniele; Mancuso, Michelangelo; Filosto, Massimiliano; Siciliano, Gabriele

2012-01-01

59

Effect of pre-operative neuromuscular training on functional outcome after total knee replacement: a randomized-controlled trial.  

UK PubMed Central (United Kingdom)

BACKGROUND: Total Knee Replacement (TKR) is the standard treatment for patients with severe knee osteoarthritis (OA). Significant improvement in pain and function are seen after TKR and approximately 80% of patients are very satisfied with the outcome. Functional status prior to TKR is a major predictor of outcome after the intervention. Thus, improving functional status prior to surgery through exercise may improve after surgery outcome. However, results from several previous trials testing the concept have been inconclusive after surgery. METHODS/DESIGN: In a randomized controlled trial (RCT) we will test the effect of a pre-operative neuromuscular training program versus an attention control program on lower extremity function - before and after surgery. We will enroll 80 participants, aged between 55-90 years, who are scheduled for TKR. In this single-blinded RCT, the intervention group will receive a minimum of 8 and a maximum of 24 training sessions plus 3 educational sessions of the knee school. The control group will receive the 3 educational sessions only. Assessments are performed immediately before and after the intervention (before surgery), at 6? weeks, 3? months and 12? months (after surgery). The primary outcome will include the Chair Stand Test as a measure of leg strength and reaction time. Secondary outcomes are knee function and pain assessed with the self-reported Knee Injury and Osteoarthritis Outcome Score (KOOS). All measurements will be carried out by a specially trained physical therapist, blinded to group allocation. DISCUSSION: To our knowledge this is the first single-blinded RCT to test the effect of pre-operative neuromuscular training plus knee school against knee school alone--on knee function and pain, assessed immediately after the interventions prior to surgery and repeatedly after surgery. TRIAL REGISTRATION: Clinical Trials NCT00913575.

Huber EO; de Bie RA; Roos EM; Bischoff-Ferrari HA

2013-01-01

60

Influência da procainamida sobre o bloqueio neuromuscular produzido pelo rocurônio e investigação sobre o mecanismo de ação da procainamida na junção neuromuscular/ Influence of procainamide on the neuromuscular blockade caused by rocuronium and investigation on the mechanism of action of procainamide on the neuromuscular junction/ Influencia de la procainamida sobre el bloqueo neuromuscular producido por el rocuronio e investigación sobre el mecanismo de acción de la procainamida en la junción neuromuscular  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese JUSTIFICATIVA E OBJETIVOS: A potencialização da procainamida sobre o bloqueio neuromuscular produzido pela d-tubocurarina já está comprovada, porém o mecanismo é controverso. O objetivo do estudo foi avaliar a influência da procainamida no bloqueio neuromuscular produzido pelo rocurônio e investigar os mecanismos desta interação. MÉTODO: Foram utilizados 15 ratos (250 a 300 g) em preparação descrita por Bülbring. Formaram-se os seguintes grupos (n = 5 cada): (more) procainamida - 20 µg.mL-1 (Grupo I); rocurônio - 4 µg.mL-1 (Grupo II) e rocurônio - 4 µg.mL-1 e procainamida - 20 µg.mL-1 (Grupo III). Avaliaram-se: 1) a amplitude das contrações musculares sob estimulação indireta em cada grupo, antes e após a adição dos fármacos; 2) os potenciais de placa terminal em miniatura (PPTM); 3) a eficácia da 4-aminopiridina na reversão do bloqueio neuromuscular. O mecanismo da interação foi estudado em Biventer cervicis (n = 5) e diafragma de rato desnervado (n = 5), observando-se a influência da procainamida na resposta à acetilcolina antes e após a adição da procainamida. RESULTADOS: A procainamida isoladamente não alterou as respostas neuromusculares. O bloqueio produzido com o Grupo III foi de 68,6% ± 7,1%, com diferença significativa (p = 0,0067) em relação ao Grupo II (10,4% ± 4,5%), revertido pela 4-aminopiridina. A procainamida ocasionou aumento na freqüência dos PPTM, seguido de bloqueio revertido pela 4-aminopiridina. Em Biventer cervicis a procainamida aumentou a resposta à ação de contração da acetilcolina, resultado não observado com o diafragma desnervado. CONCLUSÕES: A procainamida potencializou o bloqueio produzido pelo rocurônio. As alterações observadas com PPTM e Biventer cervicis identificaram ação pré-sináptica. O antagonismo da 4-aminopiridina sobre o bloqueio dos PPTM sugeriu dessensibilização dos receptores pela procainamida. Abstract in spanish JUSTIFICATIVA Y OBJETIVOS: La potenciación de la procainamida sobre el bloqueo neuromuscular producido por la d-tubocurarina ya está comprobada, pero sin embargo el mecanismo es controvertido. El objetivo del estudio fue el de evaluar la influencia de la procainamida en el bloqueo neuromuscular producido por el rocuronio e investigar los mecanismos de esa interacción. MÉTODO: Se utilizaron 15 ratones (250 a 300 g) en preparación descrita por Bülbring. Se formaron lo (more) s siguientes grupos (n = 5 cada): procainamida - 20 µg.mL-1 (Grupo I); rocuronio - 4 µg.mL-1 (Grupo II) y rocuronio - 4µg.mL-1 y procainamida - 20µg.mL-1 (Grupo III). Se evaluó: 1) la amplitud de las contracciones musculares bajo la estimulación indirecta en cada grupo, antes y después de la adición de los fármacos; 2) los potenciales de placa terminal en miniatura (PPTM); 3) la eficacia de la 4-aminopiridina en la reversión del bloqueo neuromuscular. El mecanismo de la interacción se estudió en Biventer cervicis (n = 5) y diafragma de ratón desnervado (n = 5), observándose la influencia de la procainamida en la respuesta a la acetilcolina antes y después de la adición de la procainamida. RESULTADOS: De forma aislada, la procainamida no alteró las respuestas neuromusculares. El bloqueo producido con el Grupo III fue de 68,6% ± 7,1%, con una diferencia significativa (p = 0,0067) con relación al Grupo II (10,4% ± 4,5%), revertido por la 4-aminopiridina. La procainamida ocasionó un aumento en la frecuencia de los PPTM, seguido de bloqueo revertido por la 4-aminopiridina. En Biventer cervicis, la procainamida aumentó la respuesta a la acción de contracción de la acetilcolina, resultado no observado con el diafragma desnervado. CONCLUSIONES: La procainamida potenció el bloqueo producido por el rocuronio. Las alteraciones observadas con PPTM y Biventer cervicis identificaron una acción presináptica. El antagonismo de la 4-aminopiridina sobre el bloqueo de los PPTMs sugirió la desensibilización de los rece

Martins, Thalita Duque; Loyola, Yolanda Christina S.; Braga, Angélica de Fátima de Assunção

2007-02-01

 
 
 
 
61

Influência da procainamida sobre o bloqueio neuromuscular produzido pelo rocurônio e investigação sobre o mecanismo de ação da procainamida na junção neuromuscular Influencia de la procainamida sobre el bloqueo neuromuscular producido por el rocuronio e investigación sobre el mecanismo de acción de la procainamida en la junción neuromuscular Influence of procainamide on the neuromuscular blockade caused by rocuronium and investigation on the mechanism of action of procainamide on the neuromuscular junction  

Directory of Open Access Journals (Sweden)

Full Text Available JUSTIFICATIVA E OBJETIVOS: A potencialização da procainamida sobre o bloqueio neuromuscular produzido pela d-tubocurarina já está comprovada, porém o mecanismo é controverso. O objetivo do estudo foi avaliar a influência da procainamida no bloqueio neuromuscular produzido pelo rocurônio e investigar os mecanismos desta interação. MÉTODO: Foram utilizados 15 ratos (250 a 300 g) em preparação descrita por Bülbring. Formaram-se os seguintes grupos (n = 5 cada): procainamida - 20 µg.mL-1 (Grupo I); rocurônio - 4 µg.mL-1 (Grupo II) e rocurônio - 4 µg.mL-1 e procainamida - 20 µg.mL-1 (Grupo III). Avaliaram-se: 1) a amplitude das contrações musculares sob estimulação indireta em cada grupo, antes e após a adição dos fármacos; 2) os potenciais de placa terminal em miniatura (PPTM); 3) a eficácia da 4-aminopiridina na reversão do bloqueio neuromuscular. O mecanismo da interação foi estudado em Biventer cervicis (n = 5) e diafragma de rato desnervado (n = 5), observando-se a influência da procainamida na resposta à acetilcolina antes e após a adição da procainamida. RESULTADOS: A procainamida isoladamente não alterou as respostas neuromusculares. O bloqueio produzido com o Grupo III foi de 68,6% ± 7,1%, com diferença significativa (p = 0,0067) em relação ao Grupo II (10,4% ± 4,5%), revertido pela 4-aminopiridina. A procainamida ocasionou aumento na freqüência dos PPTM, seguido de bloqueio revertido pela 4-aminopiridina. Em Biventer cervicis a procainamida aumentou a resposta à ação de contração da acetilcolina, resultado não observado com o diafragma desnervado. CONCLUSÕES: A procainamida potencializou o bloqueio produzido pelo rocurônio. As alterações observadas com PPTM e Biventer cervicis identificaram ação pré-sináptica. O antagonismo da 4-aminopiridina sobre o bloqueio dos PPTM sugeriu dessensibilização dos receptores pela procainamida.JUSTIFICATIVA Y OBJETIVOS: La potenciación de la procainamida sobre el bloqueo neuromuscular producido por la d-tubocurarina ya está comprobada, pero sin embargo el mecanismo es controvertido. El objetivo del estudio fue el de evaluar la influencia de la procainamida en el bloqueo neuromuscular producido por el rocuronio e investigar los mecanismos de esa interacción. MÉTODO: Se utilizaron 15 ratones (250 a 300 g) en preparación descrita por Bülbring. Se formaron los siguientes grupos (n = 5 cada): procainamida - 20 µg.mL-1 (Grupo I); rocuronio - 4 µg.mL-1 (Grupo II) y rocuronio - 4µg.mL-1 y procainamida - 20µg.mL-1 (Grupo III). Se evaluó: 1) la amplitud de las contracciones musculares bajo la estimulación indirecta en cada grupo, antes y después de la adición de los fármacos; 2) los potenciales de placa terminal en miniatura (PPTM); 3) la eficacia de la 4-aminopiridina en la reversión del bloqueo neuromuscular. El mecanismo de la interacción se estudió en Biventer cervicis (n = 5) y diafragma de ratón desnervado (n = 5), observándose la influencia de la procainamida en la respuesta a la acetilcolina antes y después de la adición de la procainamida. RESULTADOS: De forma aislada, la procainamida no alteró las respuestas neuromusculares. El bloqueo producido con el Grupo III fue de 68,6% ± 7,1%, con una diferencia significativa (p = 0,0067) con relación al Grupo II (10,4% ± 4,5%), revertido por la 4-aminopiridina. La procainamida ocasionó un aumento en la frecuencia de los PPTM, seguido de bloqueo revertido por la 4-aminopiridina. En Biventer cervicis, la procainamida aumentó la respuesta a la acción de contracción de la acetilcolina, resultado no observado con el diafragma desnervado. CONCLUSIONES: La procainamida potenció el bloqueo producido por el rocuronio. Las alteraciones observadas con PPTM y Biventer cervicis identificaron una acción presináptica. El antagonismo de la 4-aminopiridina sobre el bloqueo de los PPTMs sugirió la desensibilización de los receptores por la procainamida.BACKGROUND AND OBJECTIVES: It ha

Thalita Duque Martins; Yolanda Christina S. Loyola; Angélica de Fátima de Assunção Braga

2007-01-01

62

Disturbance and recovery of trunk mechanical and neuromuscular behaviours following repetitive lifting: influences of flexion angle and lift rate on creep-induced effects.  

UK PubMed Central (United Kingdom)

UNLABELLED: Repetitive lifting is associated with an increased risk of occupational low back disorders, yet potential adverse effects of such exposure on trunk mechanical and neuromuscular behaviours were not well described. Here, 12 participants, gender balanced, completed 40 min of repetitive lifting in all combinations of three flexion angles (33, 66, and 100% of each participant's full flexion angle) and two lift rates (2 and 4 lifts/min). Trunk behaviours were obtained pre- and post-exposure and during recovery using sudden perturbations. Intrinsic trunk stiffness and reflexive responses were compromised after lifting exposures, with larger decreases in stiffness and reflexive force caused by larger flexion angles, which also delayed reflexive responses. Consistent effects of lift rate were not found. Except for reflex delay no measures returned to pre-exposure values after 20 min of recovery. Simultaneous changes in both trunk stiffness and neuromuscular behaviours may impose an increased risk of trunk instability and low back injury. PRACTITIONER SUMMARY: An elevated risk of low back disorders is attributed to repetitive lifting. Here, the effects of flexion angle and lift rate on trunk mechanical and neuromuscular behaviours were investigated. Increasing flexion angle had adverse effects on these outcomes, although lift rate had inconsistent effects and recovery time was more than 20 min.

Toosizadeh N; Bazrgari B; Hendershot B; Muslim K; Nussbaum MA; Madigan ML

2013-01-01

63

Sports involvement following ACL reconstruction is related to lower extremity neuromuscular adaptations, subjective knee function and health locus of control.  

UK PubMed Central (United Kingdom)

PURPOSE: This retrospective study compared the influence of perceived sports involvement on lower extremity neuromuscular adaptations during single-leg countermovement jumping (CMJ), perceived knee function and internal health locus of control (HLOC) scores at a minimum 2-year post-anterior cruciate ligament reconstruction. The hypothesis was that subjects with higher-level sports involvement would display significant differences compared to subjects with lower-level sports involvement. METHODS: Uninvolved and involved lower extremity EMG amplitude (1,000 Hz), vertical ground reaction force (VGRF) (500 Hz) and kinematic (60 Hz) displacement differences were determined during single-leg CMJ. These data and International Knee Documentation Committee subjective knee survey scores, Multidimensional Health Locus of Control Survey internal HLOC subscale scores and sports activity characteristics were compared by sports involvement level. RESULTS: Subjects that regarded themselves as only sporting sometimes (Group 3, n = 26) had lower IKDC survey and internal HLOC scores, were more likely to decrease sports activities by two intensity levels than highly competitive (Group 1, n = 20) and well-trained/frequently sporting (Group 2, n = 24) subjects, and had greater peak landing VGRF differences suggesting decreased involved lower extremity loading compared to Group 2. During propulsion, Group 1 had greater gluteus maximus (GM) and gastrocnemius (G) EMG differences than Groups 2 and 3. Groups 1 and 2 had decreased vastus medialis (VM) EMG differences during propulsion than Group 3. During landing, Group 1 had greater GM and G EMG differences than Group 3. CONCLUSION: Subjects with higher-level sports involvement up-regulated involved lower extremity GM and G activation and down-regulated VM activation. This adaptation may enable continued higher-level sports participation while minimizing knee joint forces. Perceived higher-level sports involvement was related to neuromuscular adaptations, better subjective knee function, a more internal HLOC and higher sports activity intensity. LEVEL OF EVIDENCE: Therapeutic case series, level IV.

Nyland J; Mauser N; Caborn DN

2013-09-01

64

Myasthenia and the neuromuscular junction.  

UK PubMed Central (United Kingdom)

PURPOSE OF REVIEW: Myasthenic syndromes are distinct disorders at the neuromuscular junction, most often with well characterized autoimmune or genetic pathology. New aspects of the dysfunctions give insight into the normal neuromuscular function in addition to giving therapeutic clues and tailoring the therapy to the pathophysiology in individual patients. RECENT FINDINGS: Patients with myasthenia gravis and congenital myasthenic syndromes should be further classified into distinct subgroups. Myasthenia gravis with low-affinity acetylcholine receptor (AChR) antibodies and myasthenia gravis with antibodies to the postsynaptic low-density lipoprotein receptor-related protein 4 represent new groups, whereas a myasthenia gravis subgroup without any detectable antibodies still persists. Myasthenia gravis with antibodies against muscle-specific kinase (MuSK) is, due to new reports, now as established as AChR-myasthenia gravis regarding disease mechanisms and recommended therapy. SUMMARY: Myasthenic syndromes and myasthenia gravis are well characterized disorders. The prognosis is generally good, apart from paraneoplastic Lambert-Eaton myasthenic syndrome. However, patients need long-term symptomatic and immunoactive treatment, this treatment to be balanced against present and potential side effects. New and more selective treatment is needed, especially for severe generalized disease. Well controlled long-term studies of sufficient power are much wanted, but new therapy has often to be tried in patients before high-class evidence of effect on myasthenia gravis has been published.

Gilhus NE

2012-10-01

65

Differences in neuromuscular control between impact and no impact roundhouse kick in athletes of different skill levels.  

UK PubMed Central (United Kingdom)

This study aimed at investigating two aspects of neuromuscular control around the hip and knee joint while executing the roundhouse kick (RK) using two techniques: Impact RK (IRK) at trunk level and No-Impact RK at face level (NIRK). The influence of technical skill level was also investigated by comparing two groups: elite Karateka and Amateurs. Surface electromyographic (sEMG) signals have been recorded from the Vastus Lateralis (VL), Biceps Femoris (BF), Rectus Femoris (RF), Gluteus Maximum (GM) and Gastrocnemious (GA) muscles of the kicking leg in six Karateka and six Amateurs performing the RKs. Hip and knee kinematics were also assessed. EMG data were rectified, filtered and normalized to the maximal value obtained for each muscle over all trials; co-activation (CI) indexes of antagonist vs. overall (agonist and antagonist) activity were computed for hip and knee flexion and extension. Muscle Fiber Conduction Velocity (CV) obtained from VL and BF muscles was assessed as well. The effect of group and kick on angular velocity, CIs, and CVs was tested through a two-way ANOVA (p < 0.05). An effect of group was showed in both kicks. Karateka presented higher knee and hip angular velocity; higher BF-CV (IRK: 5.1 ± 1.0 vs. 3.5 ± 0.5 m/s; NIRK: 5.7 ± 1.3 vs. 4.1 ± 0.5 m/s), higher CIs for hip movements and knee flexion and lower CI for knee extension. The results obtained suggest the presence of a skill-dependent activation strategy in the execution of the two kicks. CV results are suggestive of an improved ability of elite Karateka to recruit fast MUs as a part of training induced neuromuscular adaptation.

Quinzi F; Camomilla V; Felici F; Di Mario A; Sbriccoli P

2013-02-01

66

Tornadoes: mechanism and control.  

UK PubMed Central (United Kingdom)

If electrical energy is invoked to account for the high velocity of tornadoes, hydrodynamics restricts the possible mechanisms of energy exchange. In particular, the vortex is driven by a line sink of electrically heated air that must extend at least 5 kilometers high. In those rare cases where heroic measures may be justified to protect a city in the path of a major tornado, some possible control measures are discussed in terms of the electrical heating mechanism.

Colgate SA

1967-09-01

67

Center of mass acceleration feedback control of standing balance by functional neuromuscular stimulation against external postural perturbations.  

UK PubMed Central (United Kingdom)

This study investigated the use of center of mass (COM) acceleration feedback for improving performance of a functional neuromuscular stimulation control system to restore standing function to a subject with complete, thoracic-level spinal cord injury. The approach for linearly relating changes in muscle stimulation to changes in COM acceleration was verified experimentally and subsequently produced data to create an input-output map driven by sensor feedback. The feedback gains were systematically tuned to reduce upper extremity (UE) loads applied to an instrumented support device while resisting external postural disturbances. Total body COM acceleration was accurately estimated (>89% variance explained) using 3-D outputs of two accelerometers mounted on the pelvis and torso. Compared to constant muscle stimulation employed clinically, feedback control of stimulation reduced UE loading by 33%. COM acceleration feedback is advantageous in constructing a standing neuroprosthesis since it provides the basis for a comprehensive control synergy about a global, dynamic variable and requires minimal instrumentation. Future work should include tuning and testing the feedback control system during functional reaching activity that is more indicative of activities of daily living.

Nataraj R; Audu ML; Triolo RJ

2013-01-01

68

Transcriptional control mechanisms  

Energy Technology Data Exchange (ETDEWEB)

This book consists of papers presented at a symposium on mechanisms of transcriptional control. Topics discussed include: 5'-regulatory elements of the human HPRT gene;nuclear factors interacting with immunoglobulin heavy and K enhancers;mitochondinal transcription factor binds novel control elements of both major promoters of human mt DNA;RNA processing and translation;chromatin structure and assembly;hormonal regulation of transcription and eukaryotic transcription systems.

Granner, D.; Rosenfeld, M.G.; Chang, S.

1987-01-01

69

Center of mass acceleration feedback control of functional neuromuscular stimulation for standing in presence of internal postural perturbations  

Directory of Open Access Journals (Sweden)

Full Text Available This study determined the feasibility and performance of center of mass (COM) acceleration feedback control of a neuroprosthesis utilizing functional neuromuscular stimulation (FNS) to restore standing balance to a single subject paralyzed by a motor and sensory complete, thoracic-level spinal cord injury. An artificial neural network (ANN) was created to map gain-modulated changes in total body COM acceleration estimated from body-mounted sensors to optimal changes in stimulation required to maintain standing. Feedback gains were systematically tuned to minimize the upper-limb (UL) loads applied by the subject to an instrumented support device during internally generated postural perturbations produced by volitional reaching and object manipulation. Total body COM acceleration was accurately estimated (>90% variance explained) from 2 three-dimensional (3-D) accelerometers mounted on the pelvis and torso. Compared with constant muscle stimulation employed clinically, COM acceleration feedback control of stimulation improved standing performance by reducing the UL loading required to resist internal postural disturbances by 27%. This case study suggests that COM acceleration feedback could potentially be advantageous in a standing neuroprosthesis since it can be implemented with only a few feedback parameters and requires minimal instrumentation for comprehensive 3-D control of dynamic standing function.

Raviraj Nataraj; Musa L. Audu, PhD; Ronald J. Triolo, PhD

2012-01-01

70

Mechanisms in environmental control  

Energy Technology Data Exchange (ETDEWEB)

The theory of implementation provides methods for decentralization of decisions in societies. By using mechanisms (game forms) it is possible (in theory) to implement attractive states in different economic environments. As an example the market mechanisms can implement Pareto-efficient and individual rational allocations in an Arrow-Debreu economic environment without market failures. And even when there exists externalities the market mechanism sometime can be used if it is possible to make a market for the goods not allocated on a market already - examples are marketable emission permits, and deposit refund systems. But environmental problems can often be explained by the existence of other market failures (e.g. asymmetric information), and then the market mechanism do not work properly. And instead of using regulation or traditional economic instruments (subsidies, charges, fees, liability insurance, marketable emission permits, or deposit refund systems) to correct the problems caused by market failures, some other methods can be used to deal with these problems. This paper contains a survey of mechanisms that can be used in environmental control when the problems are caused by the existence of public goods, externalities, asymmetric information, and indivisible goods in the economy. By examples it will be demonstrated how the Clarke-Groves mechanism, the Cournot-Lindahl mechanism, and other mechanisms can be used to solve specific environmental problems. This is only theory and examples, but a recent field study have used the Cournot-Lindahl mechanism to solve the problem of lake liming in Sweden. So this subject may be of some interests for environmental policy in the future. (au) 23 refs.

Lindeneg, K. [Univ. of Copenhagen, Inst.of Economics (Denmark)

1994-11-01

71

Neuromuscular control of scapula muscles during a voluntary task in subjects with Subacromial Impingement Syndrome. A case-control study.  

UK PubMed Central (United Kingdom)

Imbalance of neuromuscular activity in the scapula stabilizers in subjects with Subacromial Impingement Syndrome (SIS) is described in restricted tasks and specific populations. Our aim was to compare the scapular muscle activity during a voluntary movement task in a general population with and without SIS (n=16, No-SIS=15). Surface electromyography was measured from Serratus anterior (SA) and Trapezius during bilateral arm elevation (no-load, 1kg, 3kg). Mean relative muscle activity was calculated for SA and the upper (UT) and lower part of trapezius (LWT), in addition to activation ratio and time to activity onset. In spite of a tendency to higher activity among SIS 0.10-0.30 between-group differences were not significant neither in ratio of muscle activation 0.80-0.98 nor time to activity onset 0.53-0.98. The hypothesized between-group differences in neuromuscular activity of Trapezius and Serratus was not confirmed. The tendency to a higher relative muscle activity in SIS could be due to a pain-related increase in co-activation or a decrease in maximal activation. The negative findings may display the variation in the specific muscle activation patterns depending on the criteria used to define the population of impingement patients, as well as the methodological procedure being used, and the shoulder movement investigated.

Larsen CM; Søgaard K; Chreiteh SS; Holtermann A; Juul-Kristensen B

2013-10-01

72

Neuromuscular control of scapula muscles during a voluntary task in subjects with Subacromial Impingement Syndrome. A case-control study.  

Science.gov (United States)

Imbalance of neuromuscular activity in the scapula stabilizers in subjects with Subacromial Impingement Syndrome (SIS) is described in restricted tasks and specific populations. Our aim was to compare the scapular muscle activity during a voluntary movement task in a general population with and without SIS (n=16, No-SIS=15). Surface electromyography was measured from Serratus anterior (SA) and Trapezius during bilateral arm elevation (no-load, 1kg, 3kg). Mean relative muscle activity was calculated for SA and the upper (UT) and lower part of trapezius (LWT), in addition to activation ratio and time to activity onset. In spite of a tendency to higher activity among SIS 0.10-0.30 between-group differences were not significant neither in ratio of muscle activation 0.80-0.98 nor time to activity onset 0.53-0.98. The hypothesized between-group differences in neuromuscular activity of Trapezius and Serratus was not confirmed. The tendency to a higher relative muscle activity in SIS could be due to a pain-related increase in co-activation or a decrease in maximal activation. The negative findings may display the variation in the specific muscle activation patterns depending on the criteria used to define the population of impingement patients, as well as the methodological procedure being used, and the shoulder movement investigated. PMID:23787058

Larsen, C M; Søgaard, K; Chreiteh, S S; Holtermann, A; Juul-Kristensen, B

2013-06-17

73

Comparing joint kinematics and center of mass acceleration as feedback for control of standing balance by functional neuromuscular stimulation.  

UK PubMed Central (United Kingdom)

BACKGROUND: The purpose of this study was to determine the comparative effectiveness of feedback control systems for maintaining standing balance based on joint kinematics or total body center of mass (COM) acceleration, and assess their clinical practicality for standing neuroprostheses after spinal cord injury (SCI). METHODS: In simulation, controller performance was measured according to the upper extremity effort required to stabilize a three-dimensional model of bipedal standing against a variety of postural disturbances. Three cases were investigated: proportional-derivative control based on joint kinematics alone, COM acceleration feedback alone, and combined joint kinematics and COM acceleration feedback. Additionally, pilot data was collected during external perturbations of an individual with SCI standing with functional neuromuscular stimulation (FNS), and the resulting joint kinematics and COM acceleration data was analyzed. RESULTS: Compared to the baseline case of maximal constant muscle excitations, the three control systems reduced the mean upper extremity loading by 51%, 43% and 56%, respectively against external force-pulse perturbations. Controller robustness was defined as the degradation in performance with increasing levels of input errors expected with clinical deployment of sensor-based feedback. At error levels typical for body-mounted inertial sensors, performance degradation due to sensor noise and placement were negligible. However, at typical tracking error levels, performance could degrade as much as 86% for joint kinematics feedback and 35% for COM acceleration feedback. Pilot data indicated that COM acceleration could be estimated with a few well-placed sensors and efficiently captures information related to movement synergies observed during perturbed bipedal standing following SCI. CONCLUSIONS: Overall, COM acceleration feedback may be a more feasible solution for control of standing with FNS given its superior robustness and small number of inputs required.

Nataraj R; Audu ML; Triolo RJ

2012-01-01

74

Exercise in neuromuscular disease.  

Science.gov (United States)

In this review, we present an overview of the role of exercise in neuromuscular disease (NMD). We demonstrate that despite the different pathologies in NMDs, exercise is beneficial, whether aerobic/endurance or strength/resistive training, and we explore whether this benefit has a similar mechanism to that of healthy subjects. We discuss further areas for study, incorporating imaginative and novel approaches to training and its assessment in NMD. We conclude by suggesting ways to improve future trials by avoiding previous methodological flaws and drawbacks in this field. PMID:23695822

Anziska, Yaacov; Sternberg, Alex

2013-05-22

75

Exercise in neuromuscular disease.  

UK PubMed Central (United Kingdom)

In this review, we present an overview of the role of exercise in neuromuscular disease (NMD). We demonstrate that despite the different pathologies in NMDs, exercise is beneficial, whether aerobic/endurance or strength/resistive training, and we explore whether this benefit has a similar mechanism to that of healthy subjects. We discuss further areas for study, incorporating imaginative and novel approaches to training and its assessment in NMD. We conclude by suggesting ways to improve future trials by avoiding previous methodological flaws and drawbacks in this field.

Anziska Y; Sternberg A

2013-07-01

76

The effects of neuromuscular exercise on medial knee joint load post-arthroscopic partial medial meniscectomy: 'SCOPEX' a randomised control trial protocol  

DEFF Research Database (Denmark)

Background: Meniscectomy is a risk factor for knee osteoarthritis, with increased medial joint loading a likely contributor to the development and progression of knee osteoarthritis in this group. Therefore, post-surgical rehabilitation or interventions that reduce medial knee joint loading have the potential to reduce the risk of developing or progressing osteoarthritis. The primary purpose of this randomised, assessor-blind controlled trial is to determine the effects of a home-based, physiotherapist-supervised neuromuscular exercise program on medial knee joint load during functional tasks in people who have recently undergone a partial medial meniscectomy. Methods/design: 62 people aged 30-50 years who have undergone an arthroscopic partial medial meniscectomy within the previous 3 to 12 months will be recruited and randomly assigned to a neuromuscular exercise or control group using concealed allocation. The neuromuscular exercise group will attend 8 supervised exercise sessions with a physiotherapist and will perform 6 exercises at home, at least 3 times per week for 12 weeks. The control group will not receive the neuromuscular training program. Blinded assessment will be performed at baseline and immediately following the 12-week intervention. The primary outcomes are change in the peak external knee adduction moment measured by 3-dimensional analysis during normal paced walking and one-leg rise. Secondary outcomes include the change in peak external knee adduction moment during fast pace walking and one-leg hop and change in the knee adduction moment impulse during walking, one-leg rise and one-leg hop, knee and hip muscle strength, electromyographic muscle activation patterns, objective measures of physical function, as well as self-reported measures of physical function and symptoms and additional biomechanical parameters. Discussion: The findings from this trial will provide evidence regarding the effect of a home-based, physiotherapist-supervised neuromuscular exercise program on medial knee joint load during various tasks in people with a partial medial meniscectomy. If shown to reduce the knee adduction moment, neuromuscular exercise has the potential to prevent the onset of osteoarthritis or slow its progression in those with early disease.

Hall, M.; Hinman, R. S.

2012-01-01

77

Controlling and switching mechanism  

Energy Technology Data Exchange (ETDEWEB)

This patent describes a fuel injection system for an internal combustion engine, a controlling and switching mechanism using radiant energy for controlling the sequential operation of the fuel injectors. The mechanism consists of: A source of radiant energy; A first element having switching members which are activated by the radiant energy and fixed to the element, the members electrically connected in the circuit controlling their associated fuel injectors; A second element disposed between the source of radiant energy and the switching members, the second element having apertures therein through which beams of radiant energy are directed, there being an aperture for each switching member; the second element adapted for optional rotation so the each beam of radiant energy emanating from each aperture and directed toward the first element can be shifted with respect to its associated switching member; A third element disposed intermediate the first and second element, the third element having an aperture therein and rotating in timed relationship with the engine shaft, so that each switching member is activated by its associated beam by means of the rotating aperture in the third element; the duration of an energizing pulse when the switching member is activated, in degrees of engine shaft rotation, being a function of that part of the switch member illuminated by its associated beam of radiant energy.

Turetsky, I.

1986-08-12

78

A randomised controlled trial comparing sugammadex and neostigmine at different depths of neuromuscular blockade in patients undergoing laparoscopic surgery.  

UK PubMed Central (United Kingdom)

Deep neuromuscular blockade during certain surgical procedures may improve operating conditions. Sugammadex can be used to reverse deep neuromuscular blockade without waiting for spontaneous recovery. This randomised study compared recovery times from neuromuscular blockade induced by rocuronium 0.6 mg.kg(-1), using sugammadex 4 mg.kg(-1) administered at 1-2 post-tetanic count (deep blockade) or neostigmine 50 ?g.kg(-1) (plus atropine 10 ?g.kg(-1)) administered at the re-appearance of the second twitch of a train-of-four stimulation (moderate blockade), in patients undergoing laparoscopic surgery. The primary efficacy variable was the time from the start of sugammadex/neostigmine administration to recovery of the train-of-four ratio to 0.9. Patients receiving sugammadex recovered 3.4 times faster than patients receiving neostigmine (geometric mean (95% CI) recovery times of 2.4 (2.1-2.7) and 8.4 (7.2-9.8) min, respectively, p<0.0001). Moreover, 94% (62/66) of sugammadex-treated patients recovered within 5 min, vs 20% (13/65) of neostigmine-treated patients, despite the difference in the depth of neuromuscular blockade at the time of administration of both drugs. The ability to provide deep neuromuscular blockade throughout the procedure but still permit reversal at the end of surgery may enable improved surgical access and an enhanced visual field.

Geldner G; Niskanen M; Laurila P; Mizikov V; Hübler M; Beck G; Rietbergen H; Nicolayenko E

2012-09-01

79

Unmammed Gun Control Mechanism  

Directory of Open Access Journals (Sweden)

Full Text Available From ages it has been a desire of humans to achieve the ultimate in security and make his loved ones and loved things secure. It is this desire that prompted him to make the boundaries and secure them too from all unseen and unknown sources. For this it has been always necessary to maintain a huge sum of people to guard and raise alarms in cases of emergencies. To accomplish this we propose a mechanism which will employ image processing in which a camera (webcam) will be continuously observing the ‘area under surveillance’. This data will be then processed by a MatLab code which will be running on a PC and will be able to detect a particular colour (Say Red) in front of a white back ground (depicting snow). Depending on this processed data the information about the intruder location will be sent to a micro-controller (89c51) via the Serial/Parallel port of the PC and then a motor controlled gun will be used to point in the direction of the intruder. This mechanism will be online i.e. the gun will continuously be pointing in the direction of the intruder. Further depending on range (distance from the gun) (fixed range in this project) the gun can be activated and a Laser pointer will be switched ON depict “shooting the target”.

LAXMI NIDHI, PRATYUSHA ROY, SRISHTY NAYAK, RAJINE SWETHA R

2013-01-01

80

Measuring neuromuscular control dynamics during car following with continuous haptic feedback.  

UK PubMed Central (United Kingdom)

In previous research, a driver support system that uses continuous haptic feedback on the gas pedal to inform drivers of the separation to the lead vehicle was developed. Although haptic feedback has been previously shown to be beneficial, the influence of the underlying biomechanical properties of the driver on the effectiveness of haptic feedback is largely unknown. The goal of this paper is to experimentally determine the biomechanical properties of the ankle-foot complex (i.e., the admittance) while performing a car-following task, thereby separating driver responses to visual feedback from those to designed haptic feedback. An experiment was conducted in a simplified fixed-base driving simulator, where ten participants were instructed to follow a lead vehicle, with and without the support of haptic feedback. During the experiment, the lead vehicle velocity was perturbed, and small stochastic torque perturbations were applied to the pedal. Both perturbations were separated in the frequency domain to allow the simultaneous estimation of frequency response functions of both the car-following control behavior and the biomechanical admittance. For comparison to previous experiments, the admittance was also estimated during three classical motion control tasks (resist forces, relax, and give way to forces). The main experimental hypotheses were that, first, the haptic feedback would encourage drivers to adopt a "give way to force task," resulting in larger admittance compared with other tasks and, second, drivers needed less control effort to realize the same car-following performance. Time- and frequency-domain analyses provided evidence for both hypotheses. The developed methodology allows quantification of the range of admittances that a limb can adopt during vehicle control or while performing a variety of motion control tasks. It thereby allows detailed computational driver modeling and provides valuable information on how to design and evaluate continuous haptic feedback systems.

Abbink DA; Mulder M; van der Helm FC; Mulder M; Boer ER

2011-10-01

 
 
 
 
81

Measuring neuromuscular control dynamics during car following with continuous haptic feedback.  

Science.gov (United States)

In previous research, a driver support system that uses continuous haptic feedback on the gas pedal to inform drivers of the separation to the lead vehicle was developed. Although haptic feedback has been previously shown to be beneficial, the influence of the underlying biomechanical properties of the driver on the effectiveness of haptic feedback is largely unknown. The goal of this paper is to experimentally determine the biomechanical properties of the ankle-foot complex (i.e., the admittance) while performing a car-following task, thereby separating driver responses to visual feedback from those to designed haptic feedback. An experiment was conducted in a simplified fixed-base driving simulator, where ten participants were instructed to follow a lead vehicle, with and without the support of haptic feedback. During the experiment, the lead vehicle velocity was perturbed, and small stochastic torque perturbations were applied to the pedal. Both perturbations were separated in the frequency domain to allow the simultaneous estimation of frequency response functions of both the car-following control behavior and the biomechanical admittance. For comparison to previous experiments, the admittance was also estimated during three classical motion control tasks (resist forces, relax, and give way to forces). The main experimental hypotheses were that, first, the haptic feedback would encourage drivers to adopt a "give way to force task," resulting in larger admittance compared with other tasks and, second, drivers needed less control effort to realize the same car-following performance. Time- and frequency-domain analyses provided evidence for both hypotheses. The developed methodology allows quantification of the range of admittances that a limb can adopt during vehicle control or while performing a variety of motion control tasks. It thereby allows detailed computational driver modeling and provides valuable information on how to design and evaluate continuous haptic feedback systems. PMID:21536522

Abbink, David A; Mulder, Mark; van der Helm, Frans C T; Mulder, Max; Boer, Erwin R

2011-04-29

82

Características e impacto de la sedación, la analgesia y el bloqueo neuromuscular en los pacientes críticos que recibieron ventilación mecánica prolongada/ Characteristics and impact of sedation, analgesia, and neuromuscular blockage in critical patients undergoing prolonged mechanical ventilation  

Scientific Electronic Library Online (English)

Full Text Available Abstract in spanish Objetivo. Describir el uso de sedantes, analgésicos y bloqueantes neuromusculares (BNM) en los pacientes con ventilación mecánica (VM) prolongada y evaluar los factores asociados a su empleo y asociación con la mortalidad a los 28 días. Diseño. Estudio multicéntrico, prospectivo y observacional de cohorte. Ámbito. Trece unidades de cuidados intensivos (UCI) en Chile. Pacientes. Pacientes con VM superior a 48h. Excluimos los pacientes con enfermedad neurológica, c (more) irrosis hepática, insuficiencia renal crónica, sospecha de adicción a drogas y limitación precoz del esfuerzo terapéutico. Intervención. Ninguna Variables de interés principales. Proporción de uso y dosis de sedantes, analgésicos y BNM. Nivel de sedación observado (SAS [sedation-agitation scale "escala de sedación-agitación"]). Variables asociadas al nivel de la SAS, y el uso de sedantes, analgésicos y BNM. Regresión logística multivariada de variables asociadas a la mortalidad a los 28 días. Resultados. Participaron 155 pacientes (60±18 años, el 57% eran varones, SOFA 7 [6-10], APACHE II 18 [15-22], el 63% con sepsis y el 47% con lesión pulmonar aguda/síndrome de distrés respiratorio agudo. Los fármacos empleados fueron midazolam (85%; 4 mg/h [1,9-6,8]) y fentanilo (81%; 76 µg/h [39-140]). Un 30% de los pacientes usó BNM al menos un día. El 55% de la SAS fue 1-2. Existe una asociación entre el uso de BNM y la mortalidad a los 28 días, pero ésta no fue consistente en todos los modelos de uso de BNM evaluados. Conclusiones. En el grupo estudiado fue frecuente el uso de sedantes y la presencia de sedación profunda, el midazolam y el fentanilo fueron los fármacos más usados. El uso de BNM podría asociarse de forma independiente a una mayor mortalidad. Abstract in english Aim. To describe use of sedatives, analgesics, and neuromuscular blockers (NMB) in patients undergoing long-term mechanical ventilation and to assess factors associated with their use and their association with mortality at 28 days. Design. Prospective observational multicenter cohort study. Setting. Thirteen intensive care units (ICU) in Chile. Patients. Patients undergoing mechanical ventilation for more than 48h. We excluded patients with neurological disorders, cirrho (more) sis of the liver, chronic renal failure, suspected drug addiction, and early no resuscitation orders. Intervention. None. Main measurements. Proportion of use and dosage of sedatives, analgesics, and NMB. Level of sedation observed (SAS). Variables associated with the Sedation Agitation Scale (SAS), use of sedatives, analgesics, and NMB. Multivariate logistic regression of variables associated to mortality at 28 days. Results. A total of 155 patients participated (60±18 years, 57% male, SOFA 7 [6-10], APACHE II 18 [15-22], 63% with sepsis, and 47% with acute lung injury/adult respiratory distress syndrome. The drugs most frequently used were midazolam (85%, 4 [1.9-6.8]mg/hr) and fentanyl (81%, 76 [39-140]µg/hr). NMB were administered at least 1 day in 30% of patients. SAS score was 1 or 2 in 55% of patients. There was an association between NMB use and mortality at 28 days, but it was not consistent in all the models of NMB evaluated. Conclusions. Sedatives were frequently employed and deep sedation was common. Midazolam and fentanyl were the most frequently administered drugs. The use of NMB might be independently associated to greater mortality.

Tobar, E.; Bugedo, G.; Andresen, M.; Aguirre, M.; Lira, M.T.; Godoy, J.; González, H.; Hernández, A.; Tomicic, V.; Castro, J.; Jara, J.; Ugarte, H.

2009-10-01

83

Structural mechanisms of the agrin-LRP4-MuSK signaling pathway in neuromuscular junction differentiation.  

UK PubMed Central (United Kingdom)

The neuromuscular junction (NMJ) is the most extensively studied model of neuronal synaptogenesis. Acetylcholine receptor (AChR) clustering on the postsynaptic membrane is a cardinal event in the differentiation of NMJs. AChR clustering and postsynaptic differentiation is orchestrated by sophisticated interactions among three proteins: the neuron-secreted proteoglycan agrin, the co-receptor LRP4, and the muscle-specific receptor tyrosine kinase MuSK. LRP4 and MuSK act as scaffolds for multiple binding partners, resulting in a complex and dynamic network of interacting proteins that is required for AChR clustering. In this review, we discuss the structural basis for NMJ postsynaptic differentiation mediated by the agrin-LRP4-MuSK signaling pathway.

Zong Y; Jin R

2013-09-01

84

Neuromuscular disease and anesthesia.  

UK PubMed Central (United Kingdom)

Patients with neuromuscular disease pose many anesthetic challenges and are at greater risk for perioperative complications, including respiratory or cardiovascular dysfunction and pulmonary aspiration. Therefore, these patients require special precautions, including interdisciplinary communication between primary care physicians, neurologists, physiatrists, surgeons, and anesthesiologists. Preoperative evaluation and optimization of comorbid conditions is critical. These patients may have adverse response to neuromuscular blocking drugs and the reversal drugs (e.g., neostigmine). They should be used with caution and titrated based on objective neuromuscular monitoring. Drugs that potentiate neuromuscular blocking drugs should also be avoided or their doses limited if possible. The risk of malignant hyperthermia in certain neuromuscular diseases mandates avoidance of triggering agents such as succinylcholine and inhaled anesthetics. Patients with neuromuscular disease may also be sensitive to sedative-hypnotics and opioids, which should be used judiciously. Finally, the postoperative period requires close monitoring due to increased risk of postoperative cardiorespiratory dysfunction. Muscle Nerve 48: 451-460, 2013.

Romero A; Joshi GP

2013-09-01

85

Neuromuscular disease and anesthesia.  

Science.gov (United States)

Patients with neuromuscular disease pose many anesthetic challenges and are at greater risk for perioperative complications, including respiratory or cardiovascular dysfunction and pulmonary aspiration. Therefore, these patients require special precautions, including interdisciplinary communication between primary care physicians, neurologists, physiatrists, surgeons, and anesthesiologists. Preoperative evaluation and optimization of comorbid conditions is critical. These patients may have adverse response to neuromuscular blocking drugs and the reversal drugs (e.g., neostigmine). They should be used with caution and titrated based on objective neuromuscular monitoring. Drugs that potentiate neuromuscular blocking drugs should also be avoided or their doses limited if possible. The risk of malignant hyperthermia in certain neuromuscular diseases mandates avoidance of triggering agents such as succinylcholine and inhaled anesthetics. Patients with neuromuscular disease may also be sensitive to sedative-hypnotics and opioids, which should be used judiciously. Finally, the postoperative period requires close monitoring due to increased risk of postoperative cardiorespiratory dysfunction. Muscle Nerve 48: 451-460, 2013. PMID:23424048

Romero, Alan; Joshi, Girish P

2013-07-27

86

The effects of neuromuscular exercise on medial knee joint load post-arthroscopic partial medial meniscectomy: 'SCOPEX', a randomised control trial protocol  

DEFF Research Database (Denmark)

Meniscectomy is a risk factor for knee osteoarthritis, with increased medial joint loading a likely contributor to the development and progression of knee osteoarthritis in this group. Therefore, post-surgical rehabilitation or interventions that reduce medial knee joint loading have the potential to reduce the risk of developing or progressing osteoarthritis. The primary purpose of this randomised, assessor-blind controlled trial is to determine the effects of a home-based, physiotherapist-supervised neuromuscular exercise program on medial knee joint load during functional tasks in people who have recently undergone a partial medial meniscectomy.

Hall, Michelle; Hinman, Rana S

2012-01-01

87

Neuromuscular strategies for lumbopelvic control during frontal and sagittal plane movement challenges differ between people with and without low back pain.  

UK PubMed Central (United Kingdom)

Observation-based assessments of movement are a standard component in clinical assessment of patients with non-specific low back pain. While aberrant motion patterns can be detected visually, clinicians are unable to assess underlying neuromuscular strategies during these tests. The purpose of this study was to compare coordination of the trunk and hip muscles during 2 commonly used assessments for lumbopelvic control in people with low back pain (LBP) and matched control subjects. Electromyography was recorded from hip and trunk muscles of 34 participants (17 with LBP) during performance of the Active Hip Abduction (AHAbd) and Active Straight Leg Raise (ASLR) tests. Relative muscle timing was calculated using cross-correlation. Participants with LBP demonstrated a variable strategy, while control subjects used a consistent proximal to distal activation strategy during both frontal and sagittal plane movements. Findings from this study provide insight into underlying neuromuscular control during commonly used assessment tests for patients with LBP that may help to guide targeted intervention approaches.

Nelson-Wong E; Poupore K; Ingvalson S; Dehmer K; Piatte A; Alexander S; Gallant P; McClenahan B; Davis AM

2013-09-01

88

A randomized controlled trial of surface neuromuscular electrical stimulation applied early after acute stroke: effects on wrist pain, spasticity and contractures.  

UK PubMed Central (United Kingdom)

OBJECTIVES: To investigate effects of surface neuromuscular electrical stimulation applied early after stroke to the wrist and finger extensor muscles on upper limb pain, spasticity and contractures in patients with no functional arm movement. DESIGN: Secondary analysis from a Phase II, randomized, controlled, single-blind study. SETTING: An acute hospital stroke unit. SUBJECTS: Patients with no useful arm function within six weeks of a first stroke. INTERVENTION: Patients were randomized to treatment (30-minute sessions of surface neuromuscular stimulation to wrist and finger extensors and 45 minutes of physiotherapy) or control (45 minutes of physiotherapy) groups. All patients had access to routine care. Treatment was given for six weeks from recruitment. RESULTS: Ninety patients (49% male, median age 74 years (range 32-98), median time since stroke onset three weeks (range one to six weeks)) were included. Treatment compliance was variable (mean 28%). The treatment prevented the development of pain (mean difference in rate of change 0.4 units/week, 95% confidence interval (CI) 0.09 to 0.6). Treatment may have prevented a deterioration in contractures (quantified by measuring passive range of movement) in severely disabled patients (mean rate of deterioration -0.5 deg/week; 95% CI -0.9 to -0.06). There were no significant changes in stiffness and spasticity. CONCLUSION: Surface neuromuscular electrical stimulation reduces pain in stroke patients with a non-functional arm. There was some evidence that treatment with electrical stimulation was beneficial in reducing contractures. Treatment had no effect on spasticity.

Malhotra S; Rosewilliam S; Hermens H; Roffe C; Jones P; Pandyan AD

2013-07-01

89

Neuromuscular fatigue in racquet sports.  

UK PubMed Central (United Kingdom)

This article describes the physiologic and neural mechanisms that cause neuromuscular fatigue in racquet sports: table tennis, tennis, squash, and badminton. In these intermittent and dual activities, performance may be limited as a match progresses because of a reduced central activation, linked to changes in neurotransmitter concentration or in response to afferent sensory feedback. Alternatively, modulation of spinal loop properties may occur because of changes in metabolic or mechanical properties within the muscle. Finally, increased fatigue manifested by mistimed strokes, lower speed, and altered on-court movements may be caused by ionic disturbances and impairments in excitation-contraction coupling properties. These alterations in neuromuscular function contribute to decrease in racquet sports performance observed under fatigue.

Girard O; Millet GP

2009-02-01

90

Aminoglycoside antibiotics: interaction with trimethaphan at the neuromuscular junctions.  

UK PubMed Central (United Kingdom)

Trimethaphan, a ganglionic blocking agent which is administered by intravenous drip to produce controlled hypotension during surgery, produces a complete neuromuscular blockade at the isolated phrenic nerve-hemidiaphragm preparation of the rat at a concentration of 0.3 mmol X l-1. This blockade is not reversed by neostigmine, a cholinesterase inhibitor, nor by calcium chloride, and this action is attributed to the local anaesthetic activity of the drug. Trimethaphan (1.5 X 10(-2) mmol X l-1) interacts with the following aminoglycoside antibiotics: gentamicin (0.04), streptomycin (0.05), netilmicin (0.06), amikacin (0.11), sisomicin (0.14), kanamycin (0.17), tobramycin (0.18) and dibekacin (0.21 mmol X l-1) to produce a complete neuromuscular blockade. These pharmacodynamic interactions of trimethaphan and aminoglycoside antibiotics occur at significantly reduced concentrations of the interacting drugs which are very close to the ones obtained after administration of therapeutic doses. When trimethaphan or aminoglycoside antibiotics are used alone at the above reduced concentrations they do not exert any neuromuscular blocking activity. The neuromuscular blockade which is obtained after the interaction of trimethaphan with aminoglycoside antibiotics is not reversed by either neostigmine or calcium chloride, although the neuromuscular blockade which is produced by aminoglycoside antibiotics alone is reversed by calcium chloride. It is concluded that the local anaesthetic effect of trimethaphan is the predominant factor of the mechanism of the above interactions. These interactions may produce severe respiratory disturbances (respiratory depression or apnoea) to the patients, during the perioperative period, which can be reversed only with artificial ventilation.

Paradelis AG; Crassaris LG; Karachalios DN; Triantaphyllidis CJ

1987-01-01

91

Comparison of the effectiveness of active and passive neuromuscular electrical stimulation of hemiplegic upper extremities: a randomized, controlled trial.  

UK PubMed Central (United Kingdom)

To compare the efficacy of electromyography (EMG)-triggered (active) neuromuscular electrical stimulation (NMES) and passive NMES in enhancing the upper extremity (UE) motor and functional recovery of subacute and chronic stage stroke patients. Thirty-one hemiplegic patients were randomly assigned to active NMES (n=11), passive NMES (n=10), and control (sham stimulation) (n=10) groups. Each treatment regimen was applied five times per week for 45 min for 3 weeks. All of the patients performed the same neurophysiologic exercise program for 45 min five times per week for 3 weeks. Patients were assessed by the UE component of the Fugl-Meyer Motor Assessment (UE-FMA), the self-care component of the Functional Independence Measure (self-care FIM), the Motor Activity Log (MAL), goniometric measurements of active wrist and metacarpophalangeal joint extension, surface EMG potentials, grip strength, and the modified Ashworth scale in a blinded manner. Data were obtained before and at the end of the treatment. Participants were similar in all clinical and demographic features (P>0.05). All groups were comparable with respect to UE-FMA, MAL, self-care FIM, wrist and finger flexor spasticity, active range of motion (ROM), grip strength, and surface EMG potentials before treatment (P>0.05). The active ROM, grip strength, FMA, FIM, surface EMG potentials, and MAL: amount of use were significantly improved in the EMG-triggered NMES group compared with the controls (P<0.05). The active wrist extension ROM and FMA scores were significantly improved in the passive NMES group compared with the controls (P<0.05). There were no statistically significant differences between active and passive NMES groups in any of the parameters evaluated at the end of the treatment (P>0.05). Both active and passive NMES as adjuvant therapy in the neurophysiologic exercise program effectively enhanced the UE motor and functional recovery of stroke survivors.Vergleich der Wirksamkeit der elektromyographisch (EMG)-getriggerten (aktiven) neuromuskulären Elektrostimulation (NMES) und passiven NMES zur Verbesserung der motorischen und funktionellen Erholung der oberen Extremitäten bei Schlaganfallpatienten in der subakuten und chronischen Phase. Insgesamt 31 einseitig gelähmte Patienten wurden randomisiert den aktiven NMES- (n=11), passiven NMES- (n=10) und Kontrollgruppen (Sham-Stimulation) (n=10) zugeordnet. Jede Therapie wurde fünfmal pro Woche jeweils 45 Minuten lang über drei Wochen hinweg angewandt. Alle Patienten unterzogen sich fünfmal pro Woche jeweils 45 Minuten lang über drei Wochen hinweg dem gleichen neurophysiologischen Übungsprogramm. Die Beurteilung der Patienten erfolgte anhand der Komponente "obere Extremitäten" des motorischen Funktionstests nach Fugl-Meyer (UE-FMA), der Selbstversorgungskomponente des funktionalen Selbständigkeitsindexes (Selbstversorgung FIM), des Motor Activity Log (MAL), der goniometrischen Messung der aktiven Handgelenk- und Fingergrundgelenkextension, der Oberflächen-EMG-Potenziale, der Griffstärke und der modifizierten Ashworth-Skala in verblindeter Form. Daten wurden vor und nach Abschluss der Behandlung erfasst. Die Teilnehmer schnitten bei allen klinischen und demographischen Merkmalen ähnlich ab (P<0.05). Alle Gruppen waren vergleichbar hinsichtlich UE-FMA, MAL, Selbstversorgungs-FIM, Spastizität der Handgelenks- und Fingerbeuger, aktiver Bewegungsamplitude (ROM), Griffstärke und Oberflächen-EMG-Potenziale vor der Behandlung (P>0.05). Aktive ROM, Griffstärke, FMA, FIM, Oberflächen-EMG-Potenziale und MAL: Das Ausmaß der Anwendung war in der EMG-getriggerten NMES-Gruppe verglichen mit den Teilnehmern der Kontrollgruppe signifikant verbessert (P<0.05). Die ROM- und FMA-Scores der aktiven Handgelenkextension waren in der passiven NMES-Gruppe verglichen mit der Kontrollgruppe signifikant verbessert (P<0.05). Es lagen keine statistisch signifikanten Unterschiede zwischen den aktiven und passiven NMES-Gruppen bei den zu Ende der Behandlung beurteilten Parametern vor (P&

Boyaci A; Topuz O; Alkan H; Ozgen M; Sarsan A; Yildiz N; Ardic F

2013-04-01

92

Comparison of the effectiveness of active and passive neuromuscular electrical stimulation of hemiplegic upper extremities: a randomized, controlled trial.  

Science.gov (United States)

To compare the efficacy of electromyography (EMG)-triggered (active) neuromuscular electrical stimulation (NMES) and passive NMES in enhancing the upper extremity (UE) motor and functional recovery of subacute and chronic stage stroke patients. Thirty-one hemiplegic patients were randomly assigned to active NMES (n=11), passive NMES (n=10), and control (sham stimulation) (n=10) groups. Each treatment regimen was applied five times per week for 45 min for 3 weeks. All of the patients performed the same neurophysiologic exercise program for 45 min five times per week for 3 weeks. Patients were assessed by the UE component of the Fugl-Meyer Motor Assessment (UE-FMA), the self-care component of the Functional Independence Measure (self-care FIM), the Motor Activity Log (MAL), goniometric measurements of active wrist and metacarpophalangeal joint extension, surface EMG potentials, grip strength, and the modified Ashworth scale in a blinded manner. Data were obtained before and at the end of the treatment. Participants were similar in all clinical and demographic features (P>0.05). All groups were comparable with respect to UE-FMA, MAL, self-care FIM, wrist and finger flexor spasticity, active range of motion (ROM), grip strength, and surface EMG potentials before treatment (P>0.05). The active ROM, grip strength, FMA, FIM, surface EMG potentials, and MAL: amount of use were significantly improved in the EMG-triggered NMES group compared with the controls (P0.05). Both active and passive NMES as adjuvant therapy in the neurophysiologic exercise program effectively enhanced the UE motor and functional recovery of stroke survivors.Vergleich der Wirksamkeit der elektromyographisch (EMG)-getriggerten (aktiven) neuromuskulären Elektrostimulation (NMES) und passiven NMES zur Verbesserung der motorischen und funktionellen Erholung der oberen Extremitäten bei Schlaganfallpatienten in der subakuten und chronischen Phase. Insgesamt 31 einseitig gelähmte Patienten wurden randomisiert den aktiven NMES- (n=11), passiven NMES- (n=10) und Kontrollgruppen (Sham-Stimulation) (n=10) zugeordnet. Jede Therapie wurde fünfmal pro Woche jeweils 45 Minuten lang über drei Wochen hinweg angewandt. Alle Patienten unterzogen sich fünfmal pro Woche jeweils 45 Minuten lang über drei Wochen hinweg dem gleichen neurophysiologischen Übungsprogramm. Die Beurteilung der Patienten erfolgte anhand der Komponente "obere Extremitäten" des motorischen Funktionstests nach Fugl-Meyer (UE-FMA), der Selbstversorgungskomponente des funktionalen Selbständigkeitsindexes (Selbstversorgung FIM), des Motor Activity Log (MAL), der goniometrischen Messung der aktiven Handgelenk- und Fingergrundgelenkextension, der Oberflächen-EMG-Potenziale, der Griffstärke und der modifizierten Ashworth-Skala in verblindeter Form. Daten wurden vor und nach Abschluss der Behandlung erfasst. Die Teilnehmer schnitten bei allen klinischen und demographischen Merkmalen ähnlich ab (P0.05). Aktive ROM, Griffstärke, FMA, FIM, Oberflächen-EMG-Potenziale und MAL: Das Ausmaß der Anwendung war in der EMG-getriggerten NMES-Gruppe verglichen mit den Teilnehmern der Kontrollgruppe signifikant verbessert (P<0.05). Die ROM- und FMA-Scores der aktiven Handgelenkextension waren in der passiven NMES-Gruppe verglichen mit der Kontrollgruppe signifikant verbessert (P<0.05). Es lagen keine statistisch signifikanten Unterschiede zwischen den aktiven und passiven NMES-Gruppen bei den zu Ende der Behandlung beurteilten Parametern vor (P&

Boyaci, Ahmet; Topuz, Oya; Alkan, Hakan; Ozgen, Merih; Sarsan, Ayse; Yildiz, Necmettin; Ardic, Fusun

2013-04-11

93

RAPID NONDESTRUCTIVE MECHANICAL STRESS CONTROL  

Directory of Open Access Journals (Sweden)

Full Text Available The paper considers problems of nondestructive mechanical stress control device design. An analytical expression for calculation of EMF induced in the measuring winding of a converter is obtained. The automatic control system developed linearizes the converter output voltage versus mechanical intensity.

V.F. Bezotosniy; V.V. Kozlov; O.V. Nabokova

2013-01-01

94

Effects of neuromuscular training (NEMEX-TJR) on patient-reported outcomes and physical function in severe primary hip or knee osteoarthritis : a controlled before-and-after study  

DEFF Research Database (Denmark)

The benefits of exercise in mild and moderate knee or hip osteoarthritis (OA) are apparent, but the evidence in severe OA is less clear. We recently reported that neuromuscular training was well tolerated and feasible in patients with severe primary hip or knee OA. The aims of this controlled before-and-after study were to compare baseline status to an age-matched population-based reference group and to examine the effects of neuromuscular training on patient-reported outcomes and physical function in patients with severe primary OA of the hip or knee.

Ageberg, Eva; Nilsdotter, Anna

2013-01-01

95

Neuromuscular Diseases and Breathing  

Science.gov (United States)

... Help MDA Search form Search Neuromuscular Diseases and Breathing Breathing is accomplished with the effort of respiratory muscles. ... as air leaves the lungs. The process of breathing in and out, taking in oxygen and exhaling ...

96

Regulation and restoration of motoneuronal synaptic transmission during neuromuscular regeneration in the pulmonate snail Helisoma trivolvis.  

Science.gov (United States)

Regeneration of motor systems involves reestablishment of central control networks, reinnervation of muscle targets by motoneurons, and reconnection of neuromodulatory circuits. Still, how these processes are integrated as motor function is restored during regeneration remains ill defined. Here, we examined the mechanisms underlying motoneuronal regeneration of neuromuscular synapses related to feeding movements in the pulmonate snail Helisoma trivolvis. Neurons B19 and B110, although activated during different phases of the feeding pattern, innervate similar sets of muscles. However, the percentage of muscle fibers innervated, the efficacy of excitatory junction potentials, and the strength of muscle contractions were different for each cell's specific connections. After peripheral nerve crush, a sequence of transient electrical and chemical connections formed centrally within the buccal ganglia. Neuromuscular synapse regeneration involved a three-phase process: the emergence of spontaneous synaptic transmission (P1), the acquisition of evoked potentials of weak efficacy (P2), and the establishment of functional reinnervation (P3). Differential synaptic efficacy at muscle contacts was recapitulated in cell culture. Differences in motoneuronal presynaptic properties (i.e., quantal content) were the basis of disparate neuromuscular synapse function, suggesting a role for retrograde target influences. We propose a homeostatic model of molluscan motor system regeneration. This model has three restoration events: (1) transient central synaptogenesis during axonal outgrowth, (2) intermotoneuronal inhibitory synaptogenesis during initial neuromuscular synapse formation, and (3) target-dependent regulation of neuromuscular junction formation. PMID:21876114

Turner, M B; Szabo-Maas, T M; Poyer, J C; Zoran, M J

2011-08-01

97

Does neuromuscular electrical stimulation enhance the effectiveness of an exercise programme in subjects with knee osteoarthritis? A randomized controlled trial.  

UK PubMed Central (United Kingdom)

OBJECTIVE: To determine whether neuromuscular electrical stimulation applied to the quadriceps femoris muscle will enhance the effectiveness of an exercise programme in patients with knee osteoarthritis. DESIGN: A randomized trial with parallel intervention treatment groups. SETTING: Outpatient physical therapy clinic. SUBJECTS: Fifty participants (mean age (SD) 68.9 (7.7) years) with symptomatic idiopathic knee osteoarthritis and radiographic evidence (grade ? II Kelgren's classification). INTERVENTIONS: Participants were randomized into one of two groups receiving 12 biweekly treatments: An exercise-only group or an exercise combined with neuromuscular electrical stimulation group (biphasic pulses, at 75 Hz and 250 µs phase duration). MAIN MEASURES: Knee pain intensity; maximal voluntary isometric contraction and voluntary activation of the quadriceps femoris muscle; measures of functional performance. RESULTS: A significant interaction effect (P = 0.01) indicated greater improvement in pain for the electrical stimulation group. The mean (SD) change in pain intensity was from 7.5 ± 2 to 5 ± 2.2 and from 7.4 ± 1.9 to 3.3 ± 2.4 in the exercise and electrical stimulation groups, respectively. A significant treatment effect was also noted for the voluntary activation of the quadriceps femoris, which increased by 22.2% in the electrical stimulation group and by 9.6% in the exercise group (P = 0.045). Significant improvements were observed in both groups in all remaining measures, with no differences between groups. CONCLUSIONS: Electrical stimulation treatment to the quadriceps femoris enhanced the effectiveness of an exercise programme in alleviating pain and improving voluntary activation in patients with knee osteoarthritis, but did not enhance its effect on muscle strength or functional performance.

Elboim-Gabyzon M; Rozen N; Laufer Y

2013-03-01

98

Control elements in mechanism simulation  

Directory of Open Access Journals (Sweden)

Full Text Available The work reported in this paper is a step towards a system for multidisciplinary simulation of structure, mechanism and control elements. The control part of the system is implemented as a subroutine called from the mechanism/FEM package. While Newmark's/beta-method is used to integrate the second order mechanism/FEM part, the Lobatto IIIC algorithm is applied to the first order control elements. Preliminary experiments show that this is a workable solution. The package will be further developed to include more elements, improve the performance and add enhanced graphics. The control part can easily be used as a stand alone simulator for the integration of first order differential/algebraic equations.

Torleif Iversen

1989-01-01

99

Oxidative stress disrupts purinergic neuromuscular transmission in the inflamed colon.  

UK PubMed Central (United Kingdom)

Abstract? Colitis, induced by trinitrobenzene sulfonic acid (TNBS) in guinea pig, leads to decreased purinergic neuromuscular transmission resulting in a reduction in inhibitory junction potentials (IJPs) in colonic circular muscle. We explored possible mechanisms responsible for this inflammation-induced neurotransmitter plasticity. Previous studies have suggested that the deficit in inflamed tissue involves decreased ATP release. We therefore hypothesized that decreased purinergic transmission results from inflammation-induced free radical damage to mitochondria, leading to decreased purine synthesis and release. Stimulus-induced release of purines was measured using high-performance liquid chromatography, and quantities of all purines measured were significantly reduced in the inflamed colons as compared to controls. To test whether decreased mitochondrial function affects the IJP, colonic muscularis preparations were treated with the mitochondrial ATP synthase inhibitors oligomycin or dicyclohexylcarbodiimide, which resulted in a significant reduction of IJP amplitude. Induction of oxidative stress in vitro, by addition of H2O2 to the preparation, also significantly reduced IJP amplitude. Purinergic neuromuscular transmission was significantly restored in TNBS-inflamed guinea pigs, and in dextran sodium sulfate-inflamed mice, treated with a free radical scavenger. Furthermore, propulsive motility in the distal colons of guinea pigs with TNBS colitis was improved by in vivo treatment with the free radical scavenger. We conclude that oxidative stress contributes to the reduction in purinergic neuromuscular transmission measured in animal models of colitis, and that these changes can be prevented by treatment with a free radical scavenger, resulting in improved motility.

Roberts JA; Durnin L; Sharkey KA; Mutafova-Yambolieva VN; Mawe GM

2013-08-01

100

A randomized controlled trail of combination therapy of neuromuscular electrical stimulation and balloon dilatation in the treatment of radiation-induced dysphagia in nasopharyngeal carcinoma patients.  

UK PubMed Central (United Kingdom)

Dysphagia is a most common complication induced by radiotherapy in nasopharyngeal carcinoma (NPC) patients. This randomized controlled trail (RCT) was performed to evaluate the therapeutic effect of combination therapy of neuromuscular electrical stimulation (NMES) and balloon dilatation in the treatment of radiation-induced dysphagia in NPC patients. Sixty NPC patients with radiation-induced dysphagia were assigned to either the combination rehabilitation group (treatment group) or the routine rehabilitation group (control group) at random. Both groups were subjected to routine rehabilitation treatment, while the combination rehabilitation group also received combination therapy of NMES and balloon dilatation for 4 months. The water swallow test (WST) and videofluoroscopic swallowing study (VFSS) were used to evaluate the severity of dysphagia. The treatment group showed a significant improvement in swallowing function when compared with the control group. When the WST was used, the efficacy rate (percentage of patients with excellent and effective results) of treatment group was higher than that of control group (90.1 vs. 76.3%), and the difference was statistically significant (?(2) = 8.55, p = 0.036). When the VFSS was used, the videofluoroscopy results in our study showed that the values of oral transit time (OTT), swallow reaction time (SRT), pharyngeal transit time (PTT) and laryngeal closure duration (LCD) in treatment group were notably improved when compared with those in control group. In conclusion, combination rehabilitation treatment can improve swallow function in the treatment of radiation-induced dysphagia in NPC patients.

Long YB; Wu XP

2013-03-01

 
 
 
 
101

Hereditary neuromuscular diseases  

Energy Technology Data Exchange (ETDEWEB)

This article presents the actual classification of neuromuscular diseases based on present expansion of our knowledge and understanding due to genetic developments. It summarizes the genetic and clinical presentations of each disorder together with CT findings, which we studied in a large group of patients with neuromuscular diseases. The muscular dystrophies as the largest and most common group of hereditary muscle diseases will be highlighted by giving detailed information about the role of CT and MRI in the differential diagnosis. The radiological features of neuromuscular diseases are atrophy, hypertrophy, pseudohypertrophy and fatty infiltration of muscles on a selective basis. Although the patterns and distribution of involvement are characteristic in some of the diseases, the definition of the type of disease based on CT scan only is not always possible.

Oezsarlak, O. E-mail: ozkan.ozsarlak@uza.be; Schepens, E.; Parizel, P.M.; Goethem, J.W. van; Vanhoenacker, F.; Schepper, A.M. de; Martin, J.J

2001-12-01

102

Hereditary neuromuscular diseases  

International Nuclear Information System (INIS)

[en] This article presents the actual classification of neuromuscular diseases based on present expansion of our knowledge and understanding due to genetic developments. It summarizes the genetic and clinical presentations of each disorder together with CT findings, which we studied in a large group of patients with neuromuscular diseases. The muscular dystrophies as the largest and most common group of hereditary muscle diseases will be highlighted by giving detailed information about the role of CT and MRI in the differential diagnosis. The radiological features of neuromuscular diseases are atrophy, hypertrophy, pseudohypertrophy and fatty infiltration of muscles on a selective basis. Although the patterns and distribution of involvement are characteristic in some of the diseases, the definition of the type of disease based on CT scan only is not always possible

2001-01-01

103

Optimal Control of Mechanical Systems  

Directory of Open Access Journals (Sweden)

Full Text Available In the present work, we consider a class of nonlinear optimal control problems, which can be called “optimal control problems in mechanics.” We deal with control systems whose dynamics can be described by a system of Euler-Lagrange or Hamilton equations. Using the variational structure of the solution of the corresponding boundary-value problems, we reduce the initial optimal control problem to an auxiliary problem of multiobjective programming. This technique makes it possible to apply some consistent numerical approximations of a multiobjective optimization problem to the initial optimal control problem. For solving the auxiliary problem, we propose an implementable numerical algorithm.

Vadim Azhmyakov

2007-01-01

104

Effect of a 6-week dynamic neuromuscular training programme on ankle joint function: A Case report  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Ankle joint sprain and the subsequent development of chronic ankle instability (CAI) are commonly encountered by clinicians involved in the treatment and rehabilitation of musculoskeletal injuries. It has recently been advocated that ankle joint post-sprain rehabilitation protocols should incorporate dynamic neuromuscular training to enhance ankle joint sensorimotor capabilities. To date no studies have reported on the effects of dynamic neuromuscular training on ankle joint positioning during landing from a jump, which has been reported as one of the primary injury mechanisms for ankle joint sprain. This case report details the effects of a 6-week dynamic neuromuscular training programme on ankle joint function in an athlete with CAI. Methods The athlete took part in a progressive 6-week dynamic neuromuscular training programme which incorporated postural stability, strengthening, plyometric, and speed/agility drills. The outcome measures chosen to assess for interventional efficacy were: 1 Cumberland Ankle Instability Tool (CAIT) scores, 2 Star Excursion Balance Test (SEBT) reach distances, 3 ankle joint plantar flexion during drop landing and drop vertical jumping, and 4 ground reaction forces (GRFs) during walking. Results CAIT and SEBT scores improved following participation in the programme. The angle of ankle joint plantar flexion decreased at the point of initial contact during the drop landing and drop vertical jumping tasks, indicating that the ankle joint was in a less vulnerable position upon landing following participation in the programme. Furthermore, GRFs were reduced whilst walking post-intervention. Conclusions The 6-week dynamic neuromuscular training programme improved parameters of ankle joint sensorimotor control in an athlete with CAI. Further research is now required in a larger cohort of subjects to determine the effects of neuromuscular training on ankle joint injury risk factors.

O'Driscoll Jeremiah; Kerin Fearghal; Delahunt Eamonn

2011-01-01

105

Effect of a 6-week dynamic neuromuscular training programme on ankle joint function: A Case report.  

UK PubMed Central (United Kingdom)

BACKGROUND: Ankle joint sprain and the subsequent development of chronic ankle instability (CAI) are commonly encountered by clinicians involved in the treatment and rehabilitation of musculoskeletal injuries. It has recently been advocated that ankle joint post-sprain rehabilitation protocols should incorporate dynamic neuromuscular training to enhance ankle joint sensorimotor capabilities. To date no studies have reported on the effects of dynamic neuromuscular training on ankle joint positioning during landing from a jump, which has been reported as one of the primary injury mechanisms for ankle joint sprain. This case report details the effects of a 6-week dynamic neuromuscular training programme on ankle joint function in an athlete with CAI. METHODS: The athlete took part in a progressive 6-week dynamic neuromuscular training programme which incorporated postural stability, strengthening, plyometric, and speed/agility drills. The outcome measures chosen to assess for interventional efficacy were: 1 Cumberland Ankle Instability Tool (CAIT) scores, 2 Star Excursion Balance Test (SEBT) reach distances, 3 ankle joint plantar flexion during drop landing and drop vertical jumping, and 4 ground reaction forces (GRFs) during walking. RESULTS: CAIT and SEBT scores improved following participation in the programme. The angle of ankle joint plantar flexion decreased at the point of initial contact during the drop landing and drop vertical jumping tasks, indicating that the ankle joint was in a less vulnerable position upon landing following participation in the programme. Furthermore, GRFs were reduced whilst walking post-intervention. CONCLUSIONS: The 6-week dynamic neuromuscular training programme improved parameters of ankle joint sensorimotor control in an athlete with CAI. Further research is now required in a larger cohort of subjects to determine the effects of neuromuscular training on ankle joint injury risk factors.

O'Driscoll J; Kerin F; Delahunt E

2011-01-01

106

Mechanical control of electroresistive switching.  

UK PubMed Central (United Kingdom)

Hysteretic metal-insulator transitions (MIT) mediated by ionic dynamics or ferroic phase transitions underpin emergent applications for nonvolatile memories and logic devices. The vast majority of applications and studies have explored the MIT coupled to the electric field or temperarture. Here, we argue that MIT coupled to ionic dynamics should be controlled by mechanical stimuli, the behavior we refer to as the piezochemical effect. We verify this effect experimentally and demonstrate that it allows both studying materials physics and enabling novel data storage technologies with mechanical writing and current-based readout.

Kim Y; Kelly SJ; Morozovska A; Rahani EK; Strelcov E; Eliseev E; Jesse S; Biegalski MD; Balke N; Benedek N; Strukov D; Aarts J; Hwang I; Oh S; Choi JS; Choi T; Park BH; Shenoy VB; Maksymovych P; Kalinin SV

2013-09-01

107

Electrodiagnosis of disorders of neuromuscular transmission.  

UK PubMed Central (United Kingdom)

This article reviews the use of electrodiagnostic testing in disorders of neuromuscular transmission and discusses the differences between various presynaptic and postsynaptic disorders. Attention is paid to quality control issues that influence the sensitivity of repetitive nerve stimulation and single fiber electromyography. Electrodiagnostic testing, when used as an extension of the clinician's history and physical examination, will provide appropriate direction in establishing the diagnosis.

Howard JF Jr

2013-02-01

108

Kinesio Taping(®) does not alter neuromuscular performance of femoral quadriceps or lower limb function in healthy subjects: randomized, blind, controlled, clinical trial.  

Science.gov (United States)

The aim of this study was to analyze the immediate effects of applying Kinesio Taping(®) (KT) on the neuromuscular performance of femoral quadriceps, postural balance and lower limb function in healthy subjects. This is a randomized, blind, controlled, clinical trial, where sixty female volunteers (age: 23.3 ± 2.5 years; BMI: 22.2 ± 2.1 kg/m(2)) were randomly assigned to three groups of 20 subjects each: control (10 min at rest); nonelastic adhesive tape (application over the rectus femoris, vastus lateralis and vastus medialis muscles); and KT (KT application over the same muscles). All individuals were assessed for single and triple hops, postural balance (by baropodometry), peak concentric and eccentric torque and electromyographic activity of vastus lateralis, before and after interventions. No significant differences in electromyographic activity of the VL or concentric and eccentric knee peak torque were recorded, between groups and initial and final assessment in any of the three groups. We also observed no significant alteration in single and triple-hop distance and one-footed static balance between the three groups. Application of KT to RF, VL and VM muscles did not significantly change lower limb function, postural balance, knee extensor peak torque or electromyographic activity of VL muscle in healthy women. PMID:22796389

Lins, Caio Alano de Almeida; Neto, Francisco Locks; Amorim, Anita Barros Carlos de; Macedo, Liane de Brito; Brasileiro, Jamilson Simões

2012-07-15

109

Kinesio Taping(®) does not alter neuromuscular performance of femoral quadriceps or lower limb function in healthy subjects: randomized, blind, controlled, clinical trial.  

UK PubMed Central (United Kingdom)

The aim of this study was to analyze the immediate effects of applying Kinesio Taping(®) (KT) on the neuromuscular performance of femoral quadriceps, postural balance and lower limb function in healthy subjects. This is a randomized, blind, controlled, clinical trial, where sixty female volunteers (age: 23.3 ± 2.5 years; BMI: 22.2 ± 2.1 kg/m(2)) were randomly assigned to three groups of 20 subjects each: control (10 min at rest); nonelastic adhesive tape (application over the rectus femoris, vastus lateralis and vastus medialis muscles); and KT (KT application over the same muscles). All individuals were assessed for single and triple hops, postural balance (by baropodometry), peak concentric and eccentric torque and electromyographic activity of vastus lateralis, before and after interventions. No significant differences in electromyographic activity of the VL or concentric and eccentric knee peak torque were recorded, between groups and initial and final assessment in any of the three groups. We also observed no significant alteration in single and triple-hop distance and one-footed static balance between the three groups. Application of KT to RF, VL and VM muscles did not significantly change lower limb function, postural balance, knee extensor peak torque or electromyographic activity of VL muscle in healthy women.

Lins CA; Neto FL; Amorim AB; Macedo Lde B; Brasileiro JS

2013-02-01

110

Effect of experimental low back pain on neuromuscular control of the trunk in healthy volunteers and patients with chronic low back pain.  

Science.gov (United States)

Studies of electromyographic (EMG) activity and lumbopelvic rhythm have led to a better understanding of neuromuscular alterations in chronic low back pain (cLBP) patients. Whether these changes reflect adaptations to chronic pain or are induced by acute pain is still unclear. This work aimed to assess the effects of experimental LBP on lumbar erector spinae (LES) EMG activity and lumbopelvic kinematics during a trunk flexion-extension task in healthy volunteers and LBP patients. The contribution of disability to these effects was also examined. Twelve healthy participants and 14 cLBP patients performed flexion-extension tasks in three conditions; control, innocuous heat and noxious heat, applied on the skin over L5 or T7. The results indicated that noxious heat at L5 evoked specific increases in LES activity during static full trunk flexion and extension, irrespective of participants' group. Kinematic data suggested that LBP patients adopted a different movement strategy than controls when noxious heat was applied at the L5 level. Besides, high disability was associated with less kinematic changes when approaching and leaving full flexion. These results indicate that experimental pain can induce neuromechanical alterations in cLBP patients and healthy volunteers, and that higher disability in patients is associated with decreased movement pattern changes. PMID:21641235

Dubois, Jean-Daniel; Piché, Mathieu; Cantin, Vincent; Descarreaux, Martin

2011-10-01

111

Neuromuscular control of hovering wingbeat kinematics in response to distinct flight challenges in the ruby-throated hummingbird (Archilochus colubris).  

UK PubMed Central (United Kingdom)

While producing one of the highest sustained mass-specific power outputs of any vertebrate, hovering hummingbirds must also precisely modulate the activity of their primary flight muscles to vary wingbeat kinematics and modulate lift production. While recent studies have begun to explore how pectoralis (the primary downstroke muscle) neuromuscular activation and wingbeat kinematics are linked in hummingbirds, it is unclear if different species modulate these features in similar ways, or consistently in response to distinct flight challenges. In addition, little is known about how the antagonist, the supracoracoideus, is modulated to power the symmetrical hovering upstroke. We obtained simultaneous recordings of wingbeat kinematics and electromyograms (EMGs) from the pectoralis and supracoracoideus in ruby-throated hummingbirds (Archilochus colubris) while hovering under the following conditions 1) ambient air 2) air density reduction trials 3) submaximal load lifting trials and 4) maximal load lifting trials. Increased power output was achieved through increased stroke amplitude during both treatments, but wingbeat frequency only increased at low air densities. Overall, relative EMG intensity was the best predictor of stroke amplitude and is correlated with angular velocity of the wingtip. The relationship between muscle activation intensity and kinematics was independent of treatment type, indicating reduced drag on the wings in hypodense air did not lead to high wingtip angular velocities independently of increased muscle work. EMG bursts consistently began and ended before muscle shortening under all conditions. During all sustained hovering spike number per burst consistently averaged 1.2 in the pectoralis and 2.0 in the supracoracoideus. The number of spikes increased to 2.5-3 in both muscles during maximal load lifting trials. Despite the relative kinematic symmetry of the hovering downstroke and upstroke, the supracoracoideus was activated ~1 ms earlier, EMG bursts were longer (~0.9 ms), and exhibited 1.6 times as many spikes per burst. We hypothesize that earlier and more sustained activation of the supracoracoideus fibers is necessary to offset greater compliance resulting from the presence of the supracoracoid tendon.

Mahalingam S; Welch KC

2013-08-01

112

Effects of Neuromuscular Electrical Stimulation Combined with Exercises versus an Exercise Program on the Pain and the Function in Patients with Knee Osteoarthritis: A Randomized Controlled Trial  

Science.gov (United States)

Objectives. To investigate the effect of 8 weeks of NMES + Ex (neuromuscular electrical stimulation combined with exercises) on pain and functional improvement in patients with knee osteoarthritis (OA) compared to exercise (Ex) alone. Design. Randomized controlled trial. Setting. A specialty outpatient clinic. Participants. Patients (N = 100; women = 86, men = 14; age range, 50–75 years) with knee OA. Interventions. Participants were randomly assigned to NMES + Ex or Ex group. Outcome Measures. Numerical Rating Scale 0 to 10 (NRS) and the Timed Up and Go (TUG) test were the primary outcomes. The secondary outcomes used were the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Results. Following the interventions, a statistically significant improvement in both groups was observed in all outcomes assessed. For the comparison between the groups, no statistically significant difference was found between the NMES + Ex and the Ex groups in NRS (P = 0.52), TUG test (P = 0.12), and aspects of WOMAC: pain (P = 0.26), function (P = 0.23), and stiffness (P = 0.63). Conclusion. The addition of NMES to exercise did not improve the outcomes assessed in knee OA patients. This study was registered at the Australian Clinical Trials Registry (ACTRN012607000357459).

Mizusaki Imoto, Aline; Peccin, Stella; Gomes da Silva, Kelson Nonato; de Paiva Teixeira, Lucas Emmanuel Pedro; Abrahao, Marcelo Ismael; Fernandes Moca Trevisani, Virginia

2013-01-01

113

Selective activation of neuromuscular compartments within the human trapezius muscle  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Udgivelsesdato: Oct. , Task-dependent differences in relative activity between "functional" subdivisions within human muscles are well documented. Contrary, independent voluntary control of anatomical subdivisions, termed neuromuscular compartments is not observed in human muscles. Therefore, the main ...

Holtermann, A; Roeleveld, K; Mork, P J; Grönlund, C; Karlsson, J S; Andersen, L L; Olsen, H B; Zebis, M K; Sjøgaard, G

114

Neuromuscular junctional disorders.  

Science.gov (United States)

Neuromuscular junctional disorders (NMJ) in children are distinct entity. They may be acquired or hereditary. They pose problem in diagnosis because of the higher occurrence of sero negative Myasthenia Gravis (MG) cases in children. The identity of MusK antibody positivity in a good percentage of sero negative cases further adds to problems in diagnosis. The Congenital Myasthenic Syndrome (CMS) which are rare disorders of hereditary neuromuscular transmission (NMT) has to be differentiated because immunotherapy has no benefit in this group. Molecular genetic studies of these diseases helps to identify specific type of CMS which is important as other drugs like Fluoxetine, Quinidine are found to be effective in some. In infancy, all can manifest as floppy infant syndrome. The important key to diagnosis is by detailed electrophysiological studies including repetitive nerve stimulation at slow and high rates and its response to anticholinesterases and estimation of Acetyl choline receptor antibodies. Other causes of neuromuscular transmission defects viz. snake venom poisoning and that due to drugs are discussed. PMID:18716738

Girija, A S; Ashraf, V V

2008-08-21

115

Urgencias en patología neuromuscular/ Emergencies in neuromuscular pathology  

Scientific Electronic Library Online (English)

Full Text Available Abstract in spanish La debilidad muscular aguda (DMA) es el síntoma predominante de las urgencias neuromusculares, especialmente si afecta a la musculatura respiratoria u orofaríngea. La DMA es un síndrome plurietiológico y con distintos niveles lesionales en la unidad motora. Dentro del amplio grupo de enfermedades neuromusculares, las que con mayor frecuencia provocan DMA e insuficiencia respiratoria son el síndrome de Guillain-Barré (SGB) y la miastenia gravis (MG). El SGB constituy (more) e la causa más frecuente de parálisis flácida aguda; puede ocasionar fallo respiratorio en un tercio de los casos precisando ventilación mecánica. El diagnóstico preciso de este síndrome permitirá iniciar tratamiento inmunomodulador, que ha demostrado que modifica el curso de la enfermedad. Además, la valoración clínica de los pacientes y el conocimiento de sencillos tests neurofisiológicos y de función respiratoria guiarán la decisión de ventilación mecánica evitando la intubación de urgencia. La urgencia más frecuente que ocasiona la MG es la crisis miasténica, definida por el deterioro en la función bulbar con insuficiencia respiratoria aguda y riesgo de parada respiratoria. Ocurre en un 15-20% de pacientes miasténicos y puede desencadenarse por múltiples factores. Además del diagnóstico preciso de la crisis es importante la supresión de los factores desencadenantes y medidas de soporte ventilatorio. Entre las medidas farmacológicas son la plasmaféresis y las inmunoglobulinas intravenosas los instrumentos más útiles en la actualidad; estos tratamientos no sustituyen la vigilancia intensiva y el reconocimiento de los signos inminentes de fallo respiratorio que implican soporte ventilatorio invasivo o no invasivo. Abstract in english Acute muscle weakness (AMW) is the predominant symptom of neuromuscular emergencies, especially if it affects the respiratory or oropharyngeal musculature . AMW is a multi-etiological syndrome, with different lesion levels in the motor unit. Within the broad group of neuromuscular diseases, those that most frequently provoke AMW and respiratory failure are Guillain-Barré syndrome (GBS) and myasthenia gravis (MG). GBS is the most frequent cause of acute flaccid paralysis; (more) it can cause respiratory failure in a third of cases, making mechanical ventilation necessary. Accurate diagnosis of this syndrome enables immunomodulatory treatment to be started, which has been shown to modify the course of the disease. Besides, clinical evaluation of the patients and knowledge of the simple tests of neurophysiology and respiratory function will guide the decision on mechanical ventilation, avoiding emergency intubation. The most frequent emergency caused by MG is myasthenic crisis, defined by the deterioration in the bulbar function with acute respiratory insufficiency and risk of respiratory stoppage. This occurs in 15-20% of myasthenic patients and can be triggered by numerous factors. Besides early identification of the crisis, it is important to suppress the triggering factors and to provide measure of ventilatory support. Amongst the pharmacological measures, the most useful instruments at present are plasmapheresis and intravenous immunoglobulins; these treatments do not cancel the need for intensive vigilance and of checking for imminent signs of respiratory failure that will involve invasive or non-invasive ventilatory support.

Ayuso, T.; Jericó, I.

2008-01-01

116

Comparing the effects of rehabilitation swallowing therapy vs. neuromuscular electrical stimulation therapy among stroke patients with persistent pharyngeal dysphagia: a randomized controlled study.  

UK PubMed Central (United Kingdom)

BACKGROUND: Dysphagia after stroke is associated with increased mortality, higher dependence, and longer hospitalization. Different therapeutic strategies have been introduced to improve swallowing impairment. There are no current studies that compare rehabilitation swallowing therapy (RST) and neuromuscular electrical stimulation therapy (NMES). OBJECTIVE: To compare treatment outcomes between RST and NMES intervention in stroke patients with pharyngeal dysphagia. STUDY DESIGN: A randomized controlled study. MATERIAL AND METHOD: Twenty-three stroke patients with persistent pharyngeal dysphagia (RST 11, NMES 12) were enrolled in the present study. The subjects received 60 minutes of either RST or NMES treatment for five consecutive days, had two days off and then five more consecutive days of treatment for a four-week period or until they reached functional oral intake scale (FOIS) level 7. The outcome measures assessed were change in FOIS, complications related to the treatment and number of therapy sessions. RESULTS: There were no significant differences in the stroke characteristics and the VFSS results between the two groups. At the end of treatment, the average numbers of therapy sessions per subject in the RST and NMES groups were 18.36 +/- 3.23 and 17.25 +/- 5.64, respectively, a non-significant difference. Average changes in FOIS scores were 2.46 +/- 1.04 for the RST group and 3.17 +/- 1.27 for the NMES group, statistically significant at p < 0.001. No complications were observed in either group. CONCLUSION: While both RST and NMES therapy showed a positive effect in the treatment of persistent dysphagia in stroke patients, NMES was significantly superior.

Permsirivanich W; Tipchatyotin S; Wongchai M; Leelamanit V; Setthawatcharawanich S; Sathirapanya P; Phabphal K; Juntawises U; Boonmeeprakob A

2009-02-01

117

Control of a mechanical gripper with a fuzzy controller  

International Nuclear Information System (INIS)

A fuzzy logic system is used to control a mechanical gripper. System is based in a NLX230 fuzzy micro controller. Control rules are programmed by a 68020 microprocessor in the micro controller memory. Stress and its derived are used as feedback signals in the control. This system can adapt its effort to the mechanical resistance of the object between the fingers. (Author)

1995-01-01

118

Comparison between two different neuromuscular electrical stimulation protocols for the treatment of female stress urinary incontinence: a randomized controlled trial Comparação de diferentes procedimentos de estimulação elétrica neuromuscular utilizados no tratamento da incontinência urinária de esforço feminina: ensaio clínico randomizado  

Directory of Open Access Journals (Sweden)

Full Text Available BACKGROUND: Neuromuscular electrical stimulation (NMES) is widely treatment for stress urinary incontinence (SUI) but there is no consensus in literature regarding the most effective treatment parameters. OBJECTIVE: To compare two NMESintra-vaginal protocols for the treatment of SUI in women. METHODS: The study included 20 volunteers with an average age of 55.55±6.51 years and with the clinical diagnosis of SUI. Volunteers were randomly divided into two groups: group 1 (G1) received NMES with medium-frequency current and group 2 (G2) received NMES with low-frequency current. Functional assessments of pelvic floor muscles (PFM) were performed by perineometry. The severity of signs and symptoms were objectively evaluated using the 1 hour pad test and subjectively evaluated using a visual analog scale that measured the discomfort caused by the SUI. Shapiro-Wilk test was used to analyze data normality, and the Friedman test was used to analyze nonparametric data. For analysis of symptoms related to SUI the Fisher exact test and the Mann-Whitney test were used. Significance level of 5% was set for all data analysis. RESULTS: No significant differences (p>0.05) were found between groups for any of the variable assessed. The within group analysis of initial and final evaluations (after NMES) demonstrated significant differences (pCONTEXTUALIZAÇÃO: A estimulação elétrica neuromuscular (EENM) é amplamente utilizada no tratamento da incontinência urinária de esforço (IUE), no entanto não há consenso na literatura sobre os parâmetros de tratamento mais eficazes. OBJETIVO: Avaliar os procedimentos de EENM intravaginal no tratamento de mulheres com IUE. MÉTODOS: Participaram do estudo 20 voluntárias com idade média de 55,55±6,51 anos, com diagnóstico clínico de IUE. As voluntárias foram divididas aleatoriamente em dois grupos: grupo 1 (G1), que recebeu EENM com corrente de média frequência, e grupo 2 (G2), com corrente de baixa frequência. A avaliação funcional dos músculos do assoalho pélvico (MAP) foi realizada por meio de perineometria, e a severidade dos sinais e sintomas da IUE foi avaliada, objetivamente, pelo pad test de uma hora e, subjetivamente, pela Escala Visual Analógica (EVA), que mediu o desconforto causado pela incontinência. Para a análise de normalidade dos dados, utilizou-se o teste Shapiro-Wilk, seguido do teste de Friedman para dados não paramétricos. Para a análise dos sintomas relacionados à IUE, usaram-se os testes Exato de Fisher e Mann-Whitney. Em todas as análises, considerou-se o nível de significância de 5%. RESULTADOS: Não houve diferença significativa (p>0,05) entre os grupos em nenhuma variável avaliada. Na comparação intragrupos das avaliações iniciais e finais (após EENM), houve diferença significativa (p<0,05) na quantidade de urina perdida, no desconforto causado pela incontinência urinária e na pressão perineal. CONCLUSÃO: Os procedimentos de EENM utilizados neste estudo foram igualmente eficazes no tratamento da IUE.

Priscila G. J. M. Alves; Fabiana R. Nunes; Elaine C. O. Guirro

2011-01-01

119

Comparison between two different neuromuscular electrical stimulation protocols for the treatment of female stress urinary incontinence: a randomized controlled trial/ Comparação de diferentes procedimentos de estimulação elétrica neuromuscular utilizados no tratamento da incontinência urinária de esforço feminina: ensaio clínico randomizado  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese CONTEXTUALIZAÇÃO: A estimulação elétrica neuromuscular (EENM) é amplamente utilizada no tratamento da incontinência urinária de esforço (IUE), no entanto não há consenso na literatura sobre os parâmetros de tratamento mais eficazes. OBJETIVO: Avaliar os procedimentos de EENM intravaginal no tratamento de mulheres com IUE. MÉTODOS: Participaram do estudo 20 voluntárias com idade média de 55,55±6,51 anos, com diagnóstico clínico de IUE. As voluntárias for (more) am divididas aleatoriamente em dois grupos: grupo 1 (G1), que recebeu EENM com corrente de média frequência, e grupo 2 (G2), com corrente de baixa frequência. A avaliação funcional dos músculos do assoalho pélvico (MAP) foi realizada por meio de perineometria, e a severidade dos sinais e sintomas da IUE foi avaliada, objetivamente, pelo pad test de uma hora e, subjetivamente, pela Escala Visual Analógica (EVA), que mediu o desconforto causado pela incontinência. Para a análise de normalidade dos dados, utilizou-se o teste Shapiro-Wilk, seguido do teste de Friedman para dados não paramétricos. Para a análise dos sintomas relacionados à IUE, usaram-se os testes Exato de Fisher e Mann-Whitney. Em todas as análises, considerou-se o nível de significância de 5%. RESULTADOS: Não houve diferença significativa (p>0,05) entre os grupos em nenhuma variável avaliada. Na comparação intragrupos das avaliações iniciais e finais (após EENM), houve diferença significativa (p Abstract in english BACKGROUND: Neuromuscular electrical stimulation (NMES) is widely treatment for stress urinary incontinence (SUI) but there is no consensus in literature regarding the most effective treatment parameters. OBJECTIVE: To compare two NMESintra-vaginal protocols for the treatment of SUI in women. METHODS: The study included 20 volunteers with an average age of 55.55±6.51 years and with the clinical diagnosis of SUI. Volunteers were randomly divided into two groups: group 1 ( (more) G1) received NMES with medium-frequency current and group 2 (G2) received NMES with low-frequency current. Functional assessments of pelvic floor muscles (PFM) were performed by perineometry. The severity of signs and symptoms were objectively evaluated using the 1 hour pad test and subjectively evaluated using a visual analog scale that measured the discomfort caused by the SUI. Shapiro-Wilk test was used to analyze data normality, and the Friedman test was used to analyze nonparametric data. For analysis of symptoms related to SUI the Fisher exact test and the Mann-Whitney test were used. Significance level of 5% was set for all data analysis. RESULTS: No significant differences (p>0.05) were found between groups for any of the variable assessed. The within group analysis of initial and final evaluations (after NMES) demonstrated significant differences (p

Alves, Priscila G. J. M.; Nunes, Fabiana R.; Guirro, Elaine C. O.

2011-10-01

120

Differential recruitment of high affinity A1 and A2A adenosine receptors in the control of colonic neuromuscular function in experimental colitis.  

UK PubMed Central (United Kingdom)

This study investigated the expression of A(1) and A(2A) receptors in the rat colonic neuromuscular compartment, and characterized their roles in the control of motility during inflammation. Colitis was induced by 2,4-dinitrobenzenesulfonic acid. A(1), A(2A) receptors, and ecto-5'-nucleotidase (CD73, adenosine producing enzyme) mRNA expression was examined by RT-PCR. The effects of DPCPX (A(1) receptor antagonist), CCPA (A(1) receptor agonist), 4-(2-[7-amino-2-(2-furyl)[1,2,4]triazolo[2,3-a][1,3,5]triazin-5-ylamino]ethyl)phenol (A(2A) receptor antagonist), 4-[2-[[6-amino-9-(N-ethyl-b-D-ribofuranuronamidosyl)-9H-purin-2-yl]amino]ethyl]benzenepropanoic acid hydrochloride (A(2A) receptor agonist), AOPCP (CD73 inhibitor) were tested on electrically or carbachol-evoked contractions in colonic longitudinal muscle preparations. In normal colon, RT-PCR revealed the presence of A(1) receptors, A(2A) receptors and CD73, and an increased expression of A(2A) receptors and CD73 was detected in inflamed tissues. In normal colon, DPCPX or 4-(2-[7-amino-2-(2-furyl)[1,2,4]triazolo[2,3-a][1,3,5]triazin-5-ylamino]ethyl)phenol enhanced electrically-induced contractions, while in inflamed preparations the effect of DPCPX no longer occurred. In normal colon, CCPA or 4-[2-[[6-amino-9-(N-ethyl-b-D-ribofuranuronamidosyl)-9H-purin-2-yl]amino]ethyl] benzenepropanoic acid hydrochloride decreased electrically-induced contractions. Under inflammation, 4-[2-[[6-amino-9-(N-ethyl-b-D-ribofuranuronamidosyl)-9H-purin-2-yl]amino]ethyl] benzenepropanoic acid hydrochloride reduced electrically evoked contractions with higher efficacy, while the inhibition by CCPA remained unchanged. A(1) and A(2A) receptor ligands did not affect carbachol-induced contractions. AOPCP enhanced electrically-induced contractions and prevented the contractile effects of 4-(2-[7-amino-2-(2-furyl)[1,2,4]triazolo[2,3-a][1,3,5]triazin-5-ylamino]ethyl)phenol, without interfering with DPCPX, both in normal and inflamed colons. These results indicate that, in normal colon, both A(1) and A(2A) receptors contribute to the inhibitory control of motor functions at neuronal level. Under bowel inflammation, A(1) receptor loses its modulating actions, while the recruitment of A(2A) receptor by CD73-dependent endogenous adenosine drives an enhanced inhibitory control of colonic neuromotility.

Antonioli L; Fornai M; Colucci R; Awwad O; Ghisu N; Tuccori M; Del Tacca M; Blandizzi C

2011-01-01

 
 
 
 
121

Weakness and fatigue in diverse neuromuscular diseases.  

Science.gov (United States)

Weakness and fatigue are captured by the 6-minute walk test, but the relationship between these symptoms is uncertain. Comparison across neuromuscular diseases has not been examined. A cohort study of 114 patients with spinal muscular atrophy, Duchenne/Becker muscular dystrophy, myasthenia gravis, and energy failure syndromes were included. Percent-predicted distance on the 6-minute walk test was computed from normative values to determine weakness. Fatigue was determined by the decrement in distance from the first to sixth minute. Weakness was seen across all groups (61.9%) but significant fatigue was seen only in spinal muscular atrophy (21.0%). Other groups showed little fatigue. Correlation between weakness and fatigue was significant only in spinal muscular atrophy (R = -0.71; P fatigue increased significantly. These findings suggest independent mechanisms underlying weakness and fatigue in diverse neuromuscular conditions. PMID:23847297

Montes, Jacqueline; Blumenschine, Michelle; Dunaway, Sally; Alter, Aliza S; Engelstad, Kristin; Rao, Ashwini K; Chiriboga, Claudia A; Sproule, Douglas M; Vivo, Darryl C De

2013-07-11

122

Cambios en el control neuromuscular de seis músculos de miembro inferior durante CMJ máximos realizados con fatiga/ Changes in neuromuscular control of six lower limb muscles during maximum CMJ with fatigue/ Mudanças no controle neuromuscular de seis músculos de membro inferior durante a execução de CMJ máximos com fadiga  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese Há diferentes opiniões a respeito da existência de mudanças no controle muscular quando os saltos com contramovimento (CMJ) são realizados em condição de fadiga. Este artigo avalia se as atividades e a sequência temporal de ativação de seis músculos do membro inferior durante o CMJ mudam devido à fadiga. O nível de atividade variou principalmente nos músculos biarticulares. Os tempos dos picos de atividade elétrica sugerem a existência de grupos de ação (more) muscular e mudanças na sequência de ativação dentro de cada grupo. Foi possível estabelecer a existência de um padrão geral de controle muscular durante o apoio nos CMJ, com ajustes do nível e tempo de ativação que dependem do período temporal analisado e o músculo considerado. Abstract in spanish Hay diferentes opiniones respecto a si existen cambios en el control muscular cuando saltos con contramovimiento (CMJ) son realizados en condición de fatiga. Este trabajo evalúa si la actividad y la secuencia temporal de activación de seis músculos de miembro inferior durante CMJ cambian por causa de la fatiga. El nivel de actividad varió principalmente en los músculos biarticulares. Los tiempos de los picos de actividad eléctrica sugieren la existencia de grupos d (more) e acción muscular, si bien ocurren cambios en la secuencia de activación dentro de cada grupo. Fue posible establecer que existe un patrón general de control muscular durante el apoyo en los CMJ, con ajustes del nivel y tiempo de activación que dependen del periodo temporal analizado y el músculo considerado. Abstract in english Previous studies have not reached an agreement regarding changes in muscle control when countermovement jump (CMJ) tests are performed in fatigue conditions. This paper evaluates whether the activity and time activation sequence of six lower limb muscles change, due to fatigue during CMJ. We found that the activity level varied mainly in the bi-articular muscles. Also, the temporal characteristics of the electrical activity peak suggested that muscles actioned as coordina (more) ted groups, although there were changes in the activation sequence within each group. Finally, it was possible to establish a general muscle control pattern during CMJ stance phase. However, adjustments were made on activation time and level that depended on the time period analyzed and the muscle considered.

Fábrica, Gabriel; González Rodríguez, Paula; Loss, Jefferson Fagundes

2013-06-01

123

Emerging considerations in the reversal of neuromuscular blockade and residual block  

Directory of Open Access Journals (Sweden)

Full Text Available Incomplete recovery following reversal of neuromuscular blockade can present as a clinical problem in surgical patients. Emerging pharmacologic solutions may prevent such adverse outcomes in the future. We briefly review two methods of pharmacologic reversal of neuromuscular blockade. Both methods of reversal are effective. However the early studies of the new compound, sugammadex has been shown to achieve a more rapid, stable reversal of steroidal based neuromuscular blocking agents compared to neostigmine. Due to the novel mechanism of action of this agent, sugammadex has been demonstrated to be effective even when administered during profound neuromuscular block, without evidence of recurarization.

WAYNE T. NICHOLSON; JURAJ SPRUNG; CHRISTOPHER J. JANKOWSKI

2008-01-01

124

Patología neuromuscular en cuidados intensivos Neuromuscular abnormalities in critical illness  

Directory of Open Access Journals (Sweden)

Full Text Available La patología neuromuscular en los pacientes críticos ha comenzado a ser objeto de un importante número de estudios en los últimos años, si bien aún quedan muchas lagunas en el conocimiento de su etiología, patogenia, tratamiento y pronóstico. Dentro de esta patología debemos distinguir dos grandes grupos. En el primero, la debilidad muscular aparece antes del ingreso en UCI y es posible identificar una causa conocida. El síndrome de Guillain-Barré y la miastenia grave son las dos entidades que con mayor frecuencia requieren ser atendidas en nuestras unidades. En el segundo grupo, la debilidad muscular se adquiere en la UCI, en pacientes sin enfermedad neuromuscular previa, y es secundaria a la gravedad de la enfermedad que originó su ingreso en esta unidad y/o al tratamiento empleado. La polineuropatía del paciente crítico (PPC) es, de todas ellas, la entidad más precisamente definida y de la que conocemos mejor sus características clínicas, diagnóstico y pronóstico; no obstante, aún quedan muchas sombras en cuanto a su etiopatogenia. Las alteraciones de la placa neuromuscular y sobre todo la miopatía, que frecuentemente coexiste con la PPC, son las otras complicaciones del sistema nervioso periférico que se desarrollan en pacientes críticos. Los avances en el conocimiento de estas afecciones podrían tener un importante impacto, sobre todo para el desarrollo de intervenciones terapéuticas y preventivas efectivas que mejoren el pronóstico de estos pacientes.The spectrum of neuromuscular disease encountered in today's intensive care units (ICU) has evolved over the last few decades. However, in spite of many studies on neuromuscular disorders complicating critical illness as well as its epidemiology, etiology, treatment and prognosis, several key areas remain unclear. Two main groups are found among these neuromuscular abnormalities. The first group includes primary neuromuscular disorders present on admission to the ICU in which a possible etiology can be identified. Guillain-Barré syndrome and myasthenia gravis are two of the most common diseases admitted to ours units. In the second group, weakness is acquired in the ICU in the absence of preexisting neuromuscular disease. It is believed to reflect illnesses or treatments occurring in the ICU. Critical illness polyneuropathy (CIP) is the most clearly defined neuromuscular complication in this group. However, although we have better knowledge of its clinical, diagnosis, and prognosis features, its pathophysiological substrate has not been fully elucidated. Neuromuscular junction defects and specially myopathies, that frequently coexist with CIP, are the others main causes of acquired weakness in critically ill patients. Advances in understanding of these neuromuscular disorders could have an important impact in terms of developing effective preventive and therapeutic interventions that could help to improve the poor prognosis of these patients.

R. Amaya Villar; J. Garnacho-Montero; M.D. Rincón Ferrari

2009-01-01

125

Patología neuromuscular en cuidados intensivos/ Neuromuscular abnormalities in critical illness  

Scientific Electronic Library Online (English)

Full Text Available Abstract in spanish La patología neuromuscular en los pacientes críticos ha comenzado a ser objeto de un importante número de estudios en los últimos años, si bien aún quedan muchas lagunas en el conocimiento de su etiología, patogenia, tratamiento y pronóstico. Dentro de esta patología debemos distinguir dos grandes grupos. En el primero, la debilidad muscular aparece antes del ingreso en UCI y es posible identificar una causa conocida. El síndrome de Guillain-Barré y la miasteni (more) a grave son las dos entidades que con mayor frecuencia requieren ser atendidas en nuestras unidades. En el segundo grupo, la debilidad muscular se adquiere en la UCI, en pacientes sin enfermedad neuromuscular previa, y es secundaria a la gravedad de la enfermedad que originó su ingreso en esta unidad y/o al tratamiento empleado. La polineuropatía del paciente crítico (PPC) es, de todas ellas, la entidad más precisamente definida y de la que conocemos mejor sus características clínicas, diagnóstico y pronóstico; no obstante, aún quedan muchas sombras en cuanto a su etiopatogenia. Las alteraciones de la placa neuromuscular y sobre todo la miopatía, que frecuentemente coexiste con la PPC, son las otras complicaciones del sistema nervioso periférico que se desarrollan en pacientes críticos. Los avances en el conocimiento de estas afecciones podrían tener un importante impacto, sobre todo para el desarrollo de intervenciones terapéuticas y preventivas efectivas que mejoren el pronóstico de estos pacientes. Abstract in english The spectrum of neuromuscular disease encountered in today's intensive care units (ICU) has evolved over the last few decades. However, in spite of many studies on neuromuscular disorders complicating critical illness as well as its epidemiology, etiology, treatment and prognosis, several key areas remain unclear. Two main groups are found among these neuromuscular abnormalities. The first group includes primary neuromuscular disorders present on admission to the ICU in w (more) hich a possible etiology can be identified. Guillain-Barré syndrome and myasthenia gravis are two of the most common diseases admitted to ours units. In the second group, weakness is acquired in the ICU in the absence of preexisting neuromuscular disease. It is believed to reflect illnesses or treatments occurring in the ICU. Critical illness polyneuropathy (CIP) is the most clearly defined neuromuscular complication in this group. However, although we have better knowledge of its clinical, diagnosis, and prognosis features, its pathophysiological substrate has not been fully elucidated. Neuromuscular junction defects and specially myopathies, that frequently coexist with CIP, are the others main causes of acquired weakness in critically ill patients. Advances in understanding of these neuromuscular disorders could have an important impact in terms of developing effective preventive and therapeutic interventions that could help to improve the poor prognosis of these patients.

Amaya Villar, R.; Garnacho-Montero, J.; Rincón Ferrari, M.D.

2009-04-01

126

Novel vibration-exercise instrument with dedicated adaptive filtering for electromyographic investigation of neuromuscular activation.  

UK PubMed Central (United Kingdom)

Vibration exercise (VE) has been suggested as an effective methodology to improve muscle strength and power performance. Several studies link the effects of vibration training to enhanced neuromuscular demand, typically ascribed to involuntary reflex mechanisms. However, the underlying mechanisms are still unclear, limiting the identification of the most appropriate vibration training protocols. This study concerns the realization of a new vibration exercise system for the upper limbs. Amplitude, frequency, and baseline of the vibrating force, which is generated by an electromechanical actuator, can be adjusted independently. A second order model is employed to identify the relation between the generated force and the input voltage driving the actuator. Our results show a high correlation (0.99) between the second order model fit and the measured data, ensuring accurate control on the supplied force. The level of neuromuscular demand imposed by the system on the targeted muscles can be estimated by electromyography (EMG). However, EMG measurements during VE can be severely affected by motion artifacts. An adaptive least mean square algorithm is proposed to remove motion artifacts from the measured EMG data. Preliminary validation with seven volunteers showed excellent motion artifact removal, enabling reliable evaluation of the neuromuscular activation.

Xu L; Rabotti C; Mischi M

2013-03-01

127

The neuromuscular control of birdsong.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Birdsong requires complex learned motor skills involving the coordination of respiratory, vocal organ and craniomandibular muscle groups. Recent studies have added to our understanding of how these vocal subsystems function and interact during song production. The respiratory rhythm determines the t...

Suthers, R A; Goller, F; Pytte, C

128

Low-frequency neuromuscular depression is a consequence of a reduction in nerve terminal Ca2+ currents at mammalian motor nerve endings.  

UK PubMed Central (United Kingdom)

BACKGROUND: The decline in voluntary muscle contraction during low-frequency nerve stimulation is used clinically to assess the type and degree of neuromuscular block. The mechanism underlying this depression is unknown. METHODS: Simultaneous electrophysiological measurements of neurotransmitter release and prejunctional Ca currents were made at mouse neuromuscular junctions to evaluate the hypothesis that decreases in nerve terminal Ca currents are responsible for low-frequency depression. RESULTS: Under conditions generally used to measure Ca currents at the neuromuscular junction, increasing the frequency of nerve stimulation briefly from 0.017 to 0.1-1 Hz caused a simultaneous reduction in the release of the neurotransmitter acetylcholine to 52.2 ± 4.4% of control and the Ca current peak to 75.4 ± 2.0% of control (P < 0.001, n = 5 experiments for both measurements, mean ± SEM for all data). In conditions used for train-of-four monitoring (4 stimuli, 2 Hz), neurotransmitter release declined to 42.0 ± 1.0% of control and the Ca current peak declined to 75.8 ± 3.3% of control between the first and fourth stimulus (P < 0.001, n = 7 experiments for both measurements). Depression in acetylcholine release during train-of-four protocols also occurred in the absence of neuromuscular-blocking drugs. DISCUSSION: The results demonstrate that neuromuscular depression during train-of-four monitoring is due to a decline in nerve terminal Ca currents, hence reducing the release of acetylcholine. As similar processes may come into play at higher stimulation frequencies, agents that antagonize the decline in Ca currents could be used to treat conditions in which neuromuscular depression can be debilitating.

Silinsky EM

2013-08-01

129

[Neuromuscular monitoring: methods and machines].  

Science.gov (United States)

Muscle relaxing agents are clinically in use for general anaesthesia to optimize the conditions to the endotracheal intubation as well as the surgical conditions. Therefore different musclerelaxants with specific pharmacological characteristics are available. Many factors that depend on the condition of the patient and the used musclerelaxant agent influence the duration of the neuromuscular blockade. Rapid reversal of their effects, particularly in cases of profound blockades, proved to be difficult. In cases of postoperative residual paralysis hypoxic complications because of failure of the ventilation increase the morbidity and mortality of the perioperative period. To avoid these complications in cause of postoperative residual neuromuscular blockade it seems to be necessary to evaluate the status of the muscle function. For the tactile or visual assessment or the objective measurement of stimulation the train-of-four (TOF), double-burst (DBS) or tetanus-stimulation of peripheral nerves like the ulnar nerve may be used. Established methods for the objective monitoring of neuromuscular function is the mechanomyography (MMG), the acceleromyography (AMG), the electromyography (EMG), the kinemyography (KMG) and the phonomyography (PMG). A sufficient recovery of the neuromuscular transmission is reached to a TOF-ratio of 0,9 and should be aimed before the extubation at the end of surgery. No subjective evaluation of the neuromuscular recovery is able to identify residual paralysis above a TOF-ratio of 0,5. Recent studies suggest that objective methods should be used to monitor neuromuscular function to avoid postoperative residual blockades. PMID:18464216

Nauheimer, Dirk; Geldner, Götz

2008-05-01

130

Effects of carbohydrates-BCAAs-caffeine ingestion on performance and neuromuscular function during a 2-h treadmill run: a randomized, double-blind, cross-over placebo-controlled study  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Carbohydrates (CHOs), branched-chain amino acids (BCAAs) and caffeine are known to improve running performance. However, no information is available on the effects of a combination of these ingredients on performance and neuromuscular function during running. Methods The present study was designed as a randomized double-blind cross-over placebo-controlled trial. Thirteen trained adult males completed two protocols, each including two conditions: placebo (PLA) and Sports Drink (SPD: CHOs 68.6 g.L-1, BCAAs 4 g.L-1, caffeine 75 mg.L-1). Protocol 1 consisted of an all-out 2 h treadmill run. Total distance run and glycemia were measured. In protocol 2, subjects exercised for 2 h at 95% of their lowest average speeds recorded during protocol 1 (whatever the condition). Glycemia, blood lactate concentration and neuromuscular function were determined immediately before and after exercise. Oxygen consumption (V?O2), heart rate (HR) and rate of perceived exertion (RPE) were recorded during the exercise. Total fluids ingested were 2 L whatever the protocols and conditions. Results Compared to PLA, ingestion of SPD increased running performance (p = 0.01), maintained glycemia and attenuated central fatigue (p = 0.04), an index of peripheral fatigue (p = 0.04) and RPE (p = 0.006). Maximal voluntary contraction, V?O2, and HR did not differ between the two conditions. Conclusions This study showed that ingestion of a combination of CHOs, BCAAs and caffeine increased performance by about 2% during a 2-h treadmill run. The results of neuromuscular function were contrasted: no clear cut effects of SPD were observed. Trial registration ClinicalTrials.gov, http://www.clinicaltrials.gov, NCT00799630

Peltier Sébastien L; Vincent Lucile; Millet Guillaume Y; Sirvent Pascal; Morin Jean-Benoît; Guerraz Michel; Geyssant André; Lescuyer Jean-François; Feasson Léonard; Messonnier Laurent

2011-01-01

131

Development of safe mechanism for surgical robots using equilibrium point control method.  

Science.gov (United States)

This paper introduces a novel mechanism for surgical robotic systems to generate human arm-like compliant motion. The mechanism is based on the idea of the equilibrium point control hypothesis which claims that multi-joint limb movements are achieved by shifting the limbs' equilibrium positions defined by neuromuscular activity. The equilibrium point control can be implemented on a robot manipulator by installing two actuators at each joint of the manipulator, one to control the joint position, and the other to control the joint stiffness. This double-actuator mechanism allows us to arbitrarily manipulate the stiffness (or impedance) of a robotic manipulator as well as its position. Also, the force at the end-effector can be estimated based on joint stiffness and joint angle changes without using force transducers. A two-link manipulator and a three-link manipulator with the double-actuator units have been developed, and experiments and simulation results show the potential of the proposed approach. By creating the human arm-like behavior, this mechanism can improve the performance of robot manipulators to execute stable and safe movement in surgical environments by using a simple control scheme. PMID:17354936

Park, Shinsuk; Lim, Hokjin; Kim, Byeong-sang; Song, Jae-bok

2006-01-01

132

Development of safe mechanism for surgical robots using equilibrium point control method.  

UK PubMed Central (United Kingdom)

This paper introduces a novel mechanism for surgical robotic systems to generate human arm-like compliant motion. The mechanism is based on the idea of the equilibrium point control hypothesis which claims that multi-joint limb movements are achieved by shifting the limbs' equilibrium positions defined by neuromuscular activity. The equilibrium point control can be implemented on a robot manipulator by installing two actuators at each joint of the manipulator, one to control the joint position, and the other to control the joint stiffness. This double-actuator mechanism allows us to arbitrarily manipulate the stiffness (or impedance) of a robotic manipulator as well as its position. Also, the force at the end-effector can be estimated based on joint stiffness and joint angle changes without using force transducers. A two-link manipulator and a three-link manipulator with the double-actuator units have been developed, and experiments and simulation results show the potential of the proposed approach. By creating the human arm-like behavior, this mechanism can improve the performance of robot manipulators to execute stable and safe movement in surgical environments by using a simple control scheme.

Park S; Lim H; Kim BS; Song JB

2006-01-01

133

Effects of neuromuscular training (NEMEX-TJR) on patient-reported outcomes and physical function in severe primary hip or knee osteoarthritis: a controlled before-and-after study  

Science.gov (United States)

Background The benefits of exercise in mild and moderate knee or hip osteoarthritis (OA) are apparent, but the evidence in severe OA is less clear. We recently reported that neuromuscular training was well tolerated and feasible in patients with severe primary hip or knee OA. The aims of this controlled before-and-after study were to compare baseline status to an age-matched population-based reference group and to examine the effects of neuromuscular training on patient-reported outcomes and physical function in patients with severe primary OA of the hip or knee. Methods 87 patients (60–77 years) with severe primary OA of the hip (n?=?38, 55% women) or knee (n?=?49, 59% women) awaiting total joint replacement (TJR) had supervised, neuromuscular training (NEMEX-TJR) in groups with individualized level and progression of training. A reference group (n?=?43, 53% women) was included for comparison with patients’ data. Assessments included self-reported outcomes (HOOS/KOOS) and measures of physical function (chair stands, number of knee bends/30 sec, knee extensor strength, 20-meter walk test) at baseline and at follow-up before TJR. Analysis of covariance (ANCOVA) was used for comparing patients and references and elucidating influence of demographic factors on change. The paired t-test was used for comparisons within groups. Results At baseline, patients reported worse scores than the references in all HOOS/KOOS subscales (hip 27–47%, knee 14–52%, of reference scores, respectively) and had functional limitations (hip 72–85%, knee 42–85%, of references scores, respectively). NEMEX-TJR (mean 12 weeks (SD 5.6) of training) improved self-reported outcomes (hip 9–29%, knee 7–20%) and physical function (hip 3–18%, knee 5–19%) (p?Neuromuscular training with an individualized approach and gradual progression showed promise for improving patient-reported outcomes and physical function even in older patients with severe primary OA of the hip or knee.

2013-01-01

134

Effects of neuromuscular training (NEMEX-TJR) on patient-reported outcomes and physical function in severe primary hip or knee osteoarthritis: a controlled before-and-after study.  

UK PubMed Central (United Kingdom)

BACKGROUND: The benefits of exercise in mild and moderate knee or hip osteoarthritis (OA) are apparent, but the evidence in severe OA is less clear. We recently reported that neuromuscular training was well tolerated and feasible in patients with severe primary hip or knee OA. The aims of this controlled before-and-after study were to compare baseline status to an age-matched population-based reference group and to examine the effects of neuromuscular training on patient-reported outcomes and physical function in patients with severe primary OA of the hip or knee. METHODS: 87 patients (60--77 years) with severe primary OA of the hip (n = 38, 55% women) or knee (n = 49, 59% women) awaiting total joint replacement (TJR) had supervised, neuromuscular training (NEMEX-TJR) in groups with individualized level and progression of training. A reference group (n = 43, 53% women) was included for comparison with patients' data. Assessments included self-reported outcomes (HOOS/KOOS) and measures of physical function (chair stands, number of knee bends/30 sec, knee extensor strength, 20-meter walk test) at baseline and at follow-up before TJR. Analysis of covariance (ANCOVA) was used for comparing patients and references and elucidating influence of demographic factors on change. The paired t-test was used for comparisons within groups. RESULTS: At baseline, patients reported worse scores than the references in all HOOS/KOOS subscales (hip 27--47%, knee 14--52%, of reference scores, respectively) and had functional limitations (hip 72--85%, knee 42--85%, of references scores, respectively). NEMEX-TJR (mean 12 weeks (SD 5.6) of training) improved self-reported outcomes (hip 9--29%, knee 7--20%) and physical function (hip 3--18%, knee 5--19%) (p < 0.005). Between 42% and 62% of hip OA patients, and 39% and 61% of knee OA patients, displayed a clinically meaningful improvement (>=15%) in HOOS/KOOS subscales by training. The improvement in HOOS/KOOS subscale ADL was greater for patients with knee OA than hip OA, while the improvement in subscale Sport/Rec was greater for patients with hip OA than knee OA. CONCLUSIONS: Both self-reported outcomes and physical function were clearly worse compared with the reference group. Neuromuscular training with an individualized approach and gradual progression showed promise for improving patient-reported outcomes and physical function even in older patients with severe primary OA of the hip or knee.

Ageberg E; Nilsdotter A; Kosek E; Roos EM

2013-08-01

135

Informational and neuromuscular contributions to anchoring in rhythmic wrist cycling.  

UK PubMed Central (United Kingdom)

Continuous rhythmic movements are often geared toward particular points in the movement cycle, as evidenced by a local reduction in trajectory variability. These so-called anchor points provide a window into motor control, since changes in the degree of anchoring may reveal how informational and/or neuromuscular properties are exploited in the organization of rhythmic movements. The present experiment examined the relative contributions of informational timing (metronome beeps) and neuromuscular (wrist postures) constraints on anchoring by systematically varying both factors at movement reversal points. To this end, participants cycled their right wrist in a flexed, neutral, or extended posture, either self-paced or synchronized to a metronome pacing peak flexion, peak extension, or both peak flexion and extension. The effects of these manipulations were assessed in terms of kinematics, auditory-motor coordination, and muscle activity. The degree of anchoring seen at the reversal points depended on the degree of compatibility of the prevailing configuration of neuromuscular and informational timing constraints, which had largely independent effects. We further observed systematic changes in muscular activity, which revealed distinct contributions of posture- and muscle-dependent neuromuscular properties to motor control. These findings indicate that the anchor-based discretization of the control of continuous rhythmic wrist movements is determined by both informational timing and neuromuscular constraints in a task-specific manner with subtle interactions between the two, and exemplify how movement variability may be exploited to gain such insights.

Roerdink M; Ridderikhoff A; Peper CE; Beek PJ

2013-08-01

136

Informational and neuromuscular contributions to anchoring in rhythmic wrist cycling.  

Science.gov (United States)

Continuous rhythmic movements are often geared toward particular points in the movement cycle, as evidenced by a local reduction in trajectory variability. These so-called anchor points provide a window into motor control, since changes in the degree of anchoring may reveal how informational and/or neuromuscular properties are exploited in the organization of rhythmic movements. The present experiment examined the relative contributions of informational timing (metronome beeps) and neuromuscular (wrist postures) constraints on anchoring by systematically varying both factors at movement reversal points. To this end, participants cycled their right wrist in a flexed, neutral, or extended posture, either self-paced or synchronized to a metronome pacing peak flexion, peak extension, or both peak flexion and extension. The effects of these manipulations were assessed in terms of kinematics, auditory-motor coordination, and muscle activity. The degree of anchoring seen at the reversal points depended on the degree of compatibility of the prevailing configuration of neuromuscular and informational timing constraints, which had largely independent effects. We further observed systematic changes in muscular activity, which revealed distinct contributions of posture- and muscle-dependent neuromuscular properties to motor control. These findings indicate that the anchor-based discretization of the control of continuous rhythmic wrist movements is determined by both informational timing and neuromuscular constraints in a task-specific manner with subtle interactions between the two, and exemplify how movement variability may be exploited to gain such insights. PMID:23099793

Roerdink, Melvyn; Ridderikhoff, Arne; Peper, C E; Beek, Peter J

2012-10-26

137

Neuromuscular disease classification system  

Science.gov (United States)

Diagnosis of neuromuscular diseases is based on subjective visual assessment of biopsies from patients by the pathologist specialist. A system for objective analysis and classification of muscular dystrophies and neurogenic atrophies through muscle biopsy images of fluorescence microscopy is presented. The procedure starts with an accurate segmentation of the muscle fibers using mathematical morphology and a watershed transform. A feature extraction step is carried out in two parts: 24 features that pathologists take into account to diagnose the diseases and 58 structural features that the human eye cannot see, based on the assumption that the biopsy is considered as a graph, where the nodes are represented by each fiber, and two nodes are connected if two fibers are adjacent. A feature selection using sequential forward selection and sequential backward selection methods, a classification using a Fuzzy ARTMAP neural network, and a study of grading the severity are performed on these two sets of features. A database consisting of 91 images was used: 71 images for the training step and 20 as the test. A classification error of 0% was obtained. It is concluded that the addition of features undetectable by the human visual inspection improves the categorization of atrophic patterns.

Sáez, Aurora; Acha, Begoña; Montero-Sánchez, Adoración; Rivas, Eloy; Escudero, Luis M.; Serrano, Carmen

2013-06-01

138

PROLONGED NEUROMUSCULAR BLOCKADE  

Directory of Open Access Journals (Sweden)

Full Text Available We are presenting a case of prolonged neuromuscular blockade afteremergency cesarean section. A 34 years old, young lady with no previous history of any systemic illness includingneuromuscular disorder reported in the operation t heatre for cesarean section. She was offered standard protocol forgeneral anaesthesia using thiopentone sodium i/v for induction, suxamethonium i/v for intubation, and pancuroniumbromide i/v for intra-operative relaxation. Intra-operative analgesia was obtained with nalbuphine i/v (after delivery ofchild). Ampicillin and gentamicin i/v were used as prophylactic antibiotics. The patient failed to regain spontaneousbreathing effort after a lapse of two hours since the last dose of pancuronium bromide. Laboratory investigationsincluding complete blood picture, urea, creatinine, electrolytes (calcium, sodium, potassium) revealed anemia andsevere hypocalcemia. She was given fresh whole blood and calcium gluconate intravenously, in addition to othersupportive measures like ventilatory support using SIMV mode of ventilation with 40% O2. Patient started regainingbreathing effort after about 12 hours and was extubated after about 15 hours of artificial ventilation with little residualneuromuscular blocking effect. She was kept in the ICU for the next 24 hours for observation and was discharged fromICU the next day with full recovery. Conclusion Patient probably suffered from the interaction between gentamicin andpancuronium bromide, that was further potentiated by hypocalcemia and anaemia. She was given supportive care alongwith replacement of calcium, and anaemia was corrected by fresh whole blood transfusion. Patient recovereduneventfully and was discharged from ICU the next day.

SOHAIL ASGHAR

2006-01-01

139

Perceived pain and temporomandibular disorders in neuromuscular diseases.  

UK PubMed Central (United Kingdom)

Little is known about pain associated with temporomandibular disorders (TMD) in neuromuscular diseases. Inpatients (N = 134) with neuromuscular disorder diagnoses were given questionnaires to estimate pain localization and intensity. Research Diagnostic Criteria for Temporomandibular Disorders and the Temporomandibular Index (TMI) were utilized to assess TMD. Pain was reported by 116 patients (86%). Legs (52%) and arms (33%) were the most common locations for pain localization, but the highest Pearson correlations (TMI vs. perceived pain) appeared for pain located in the trunk and arms (0.861, P < 0.01). No correlation between TMI and diagnosis group existed except for "acquired myopathy" and "miscellaneous neuromuscular diseases." These results suggest that the degree of TMD does not correlate with pain according to disease, although common mechanisms might be responsible for pain development in specific body regions connected with TMD. Most important, higher levels of TMD are associated with higher levels of perceived pain.

Fischer MJ; Riedlinger K; Schoser B; Bernateck M

2009-10-01

140

Maintenance of BWR control rod drive mechanisms.  

Science.gov (United States)

Control rod drive mechanism (CRDM) replacement and rebuilding is one of the highest dose, most physically demanding, and complicated maintenance activities routinely accomplished by BWR utilities. A recent industry workshop sponsored by the Oak Ridge Nati...

R. H. Greene

1991-01-01

 
 
 
 
141

Turning off the central contribution to contractions evoked by neuromuscular electrical stimulation.  

UK PubMed Central (United Kingdom)

Neuromuscular electrical stimulation can generate contractions through both peripheral and central mechanisms. The peripheral mechanism involves the direct activation of motor axons, while the central mechanism involves the activation of sensory axons that recruit spinal neurons through a reflex pathway. For use in functional electrical stimulation. One must have control over turning the central mechanism on and off. We investigated whether inhibition developed through antagonist muscle (tibialis anterior, TA) contractions elicited by electrical stimulation or by volition can turn off the central mechanism in triceps surae. Both electrical stimulation and voluntary contractions of TA reduced or eliminated plantar flexion torque produced by the central mechanism, indicating that inhibition induced via these contractions can effectively turn off the central contribution to force. These findings suggest that patterns of electrical stimulation may be able to generate periodic muscle contractions by turning the central contribution to muscular contractions on and off.

Dean JC; Yates LM; Collins DF

2008-08-01

142

[Effect of thiamine on neuromuscular transmission in the frog  

UK PubMed Central (United Kingdom)

The action of thiamine on frog m. sartorius neuromuscular junction was investigated. Thiamine (1 X 10(-14)-1 X 10(-4) mol/l) reversibly increased miniature end-plate potential frequency, amplitude and quantal content of end-plate potentials, probability of quantal release. The role of thiamine in the regulation of synaptic transmission and mechanism of its action are discussed.

Romanenko AV

1985-01-01

143

Protein defects in neuromuscular diseases  

Directory of Open Access Journals (Sweden)

Full Text Available Muscular dystrophies are a heterogeneous group of genetically determined progressive disorders of the muscle with a primary or predominant involvement of the pelvic or shoulder girdle musculature. The clinical course is highly variable, ranging from severe congenital forms with rapid progression to milder forms with later onset and a slower course. In recent years, several proteins from the sarcolemmal muscle membrane (dystrophin, sarcoglycans, dysferlin, caveolin-3), from the extracellular matrix (alpha2-laminin, collagen VI), from the sarcomere (telethonin, myotilin, titin, nebulin), from the muscle cytosol (calpain 3, TRIM32), from the nucleus (emerin, lamin A/C, survival motor neuron protein), and from the glycosylation pathway (fukutin, fukutin-related protein) have been identified. Mutations in their respective genes are responsible for different forms of neuromuscular diseases. Protein analysis using Western blotting or immunohistochemistry with specific antibodies is of the utmost importance for the differential diagnosis and elucidation of the physiopathology of each genetic disorder involved. Recent molecular studies have shown clinical inter- and intra-familial variability in several genetic disorders highlighting the importance of other factors in determining phenotypic expression and the role of possible modifying genes and protein interactions. Developmental studies can help elucidate the mechanism of normal muscle formation and thus muscle regeneration. In the last fifteen years, our research has focused on muscle protein expression, localization and possible interactions in patients affected by different forms of muscular dystrophies. The main objective of this review is to summarize the most recent findings in the field and our own contribution.

Vainzof M.; Zatz M.

2003-01-01

144

Protein defects in neuromuscular diseases  

Scientific Electronic Library Online (English)

Full Text Available Abstract in english Muscular dystrophies are a heterogeneous group of genetically determined progressive disorders of the muscle with a primary or predominant involvement of the pelvic or shoulder girdle musculature. The clinical course is highly variable, ranging from severe congenital forms with rapid progression to milder forms with later onset and a slower course. In recent years, several proteins from the sarcolemmal muscle membrane (dystrophin, sarcoglycans, dysferlin, caveolin-3), fro (more) m the extracellular matrix (alpha2-laminin, collagen VI), from the sarcomere (telethonin, myotilin, titin, nebulin), from the muscle cytosol (calpain 3, TRIM32), from the nucleus (emerin, lamin A/C, survival motor neuron protein), and from the glycosylation pathway (fukutin, fukutin-related protein) have been identified. Mutations in their respective genes are responsible for different forms of neuromuscular diseases. Protein analysis using Western blotting or immunohistochemistry with specific antibodies is of the utmost importance for the differential diagnosis and elucidation of the physiopathology of each genetic disorder involved. Recent molecular studies have shown clinical inter- and intra-familial variability in several genetic disorders highlighting the importance of other factors in determining phenotypic expression and the role of possible modifying genes and protein interactions. Developmental studies can help elucidate the mechanism of normal muscle formation and thus muscle regeneration. In the last fifteen years, our research has focused on muscle protein expression, localization and possible interactions in patients affected by different forms of muscular dystrophies. The main objective of this review is to summarize the most recent findings in the field and our own contribution.

Vainzof, M.; Zatz, M.

2003-05-01

145

Comparison of heart rate variability response in children undergoing elective endotracheal intubation with and without neuromuscular blockade: a randomized controlled trial.  

UK PubMed Central (United Kingdom)

BACKGROUND: The routine use of neuromuscular blocking drugs (NMBD) for endotracheal intubation in children is the subject of much controversy. The analysis of heart rate variability (HRV) can reveal information about the functional state of the autonomic nervous system (ANS). AIM: The purpose of this study was to determine if HRV elucidates differences in the sympathovagal balance of children undergoing elective endo-tracheal intubation with and without neuromuscular blockade (NMB). METHODS: In this prospective study, 38 children (2-6 years) scheduled for adenotonsillectomy were randomized into two groups to receive fentanyl 2 ?g·kg(-1) and propofol 4 mg·kg(-1) , with either mivacurium 0.25 mg·kg(-1) (NMB group) or saline solution (NoNMB group) for anesthesia induction. The same experienced, blinded anesthesiologist performed endotracheal intubation. Heart rate variability, RR intervals, ECG as well as an electroencephalogram were recorded with HRV and BIS XP monitors, respectively. Heart rate variability was analyzed in the frequency domain. RESULTS: There was no significant difference in HRV changes immediately after mivacurium administration compared with an administration of saline. The groups were comparable for the bispectral index value (NMB 35 [33-41] vs NoNMB 34 [32-42]) during endotracheal intubation. Changes in both the low-frequency power and the low-/high-frequency ratio immediately after endotracheal intubation compared with the unstimulated state before laryngoscopy were significantly higher without NMB (P = 0.015 and P = 0.006, respectively), whereas there was no significant difference with respect to the high-frequency power. CONCLUSIONS: The stress response during endotracheal intubation in pediatric patients represented by the frequency domain analysis of HRV was found to be higher without NMB. When mivacurium was added to a propofol-fent-anyl induction regimen, the ANS alterations during endotracheal intubation decreased significantly.

Janda M; Bajorat J; Kudlik C; Pohl B; Schubert A; Nöldge-Schomburg G; Hofmockel R

2013-08-01

146

A reversible mechanical remote-control device  

International Nuclear Information System (INIS)

Description is given of a device for the remote control of a mechanical assembly, as regards displacements and stresses. The mechanical assembly, actuated by a motor, is characterized in that it is reversible and comprises a displacement sensor adapted to deliver a pulse each time a shaft for moving said mechanical assembly associated to said motor has rotated by one step, the sign of that pulse depending, on the direction of the rotation of the motor, said pulses feeding an adding-device, the other input of which is fed with pulses delivered by a unit controlling the motor and constituting motor positioning orders, the output of said adding-device being re-injected in the control unit, thus providing a stress return, on the one hand and introduced into the input of an amplifier-circuit controlling the torque of said motor, on the other hand. This can be applied to manipulators

1974-01-01

147

Neuromuscular activity and knee kinematics in adolescents with patellofemoral pain  

DEFF Research Database (Denmark)

This study aimed to investigate the neuromuscular control of the knee during stair descent among female adolescents with patellofemoral pain (PFP) and to report its association with self-reported clinical status assessed by the Knee Injury and Osteoarthritis Outcome Score (KOOS).

Rathleff, Michael Skovdal; Samani, Afshin

2013-01-01

148

Neuromuscular Activity and Knee Kinematics in Adolescents with Patellofemoral Pain  

DEFF Research Database (Denmark)

: Purpose: To investigate neuromuscular control of the knee during stair descent among female adolescents with Patellofemoral Pain (PFP) and report its association with self-reported clinical status assessed by the Knee injury and Osteoarthritis Outcome Score (KOOS).Methods: Fifty-seven previously untreated female adolescents diagnosed with PFP aged 15 to 19 years were recruited from schools. The control group consisted of 29 age-matched healthy female adolescents. Bipolar surface electrodes were placed on VM and VL and an electronic knee goniometer was placed at the knee to collect knee flexion/extension kinematics. The participants walked down a stairway consisting of 24 steps at their normal pace. Sample Entropy was used to quantify the complexity of the time series from surface electromyography (sEMG) and kinematics during the stance phase. Self-reported clinical status was assessed by the KOOS and maximal quadriceps torque measured using strap-mounted handheld dynamometry.Results: Female adolescents withPFP were characterized by altered neuromuscular knee control during stair descent, lower maximal quadriceps torque, and poorer KOOS scores across all five domains. Furthermore, a positive association was found between the complexity of sEMG from VL and self-reported pain determined by KOOSpain indicating larger impairments in neuromuscular knee control among those with the highest pain levels.Conclusion: The current findings show that female adolescents with PFP are characterized by altered neuromuscular control of the knee during stair descent and lower maximal quadriceps torque. These results suggest that rehabilitation is needed, and should focus on restoring neuromuscular control and muscle strength.

Rathleff, Michael Skovdal; Samani, Afshin

2013-01-01

149

Neuromuscular activity and knee kinematics in adolescents with patellofemoral pain.  

UK PubMed Central (United Kingdom)

PURPOSE: This study aimed to investigate the neuromuscular control of the knee during stair descent among female adolescents with patellofemoral pain (PFP) and to report its association with self-reported clinical status assessed by the Knee Injury and Osteoarthritis Outcome Score (KOOS). METHODS: Fifty-seven previously untreated female adolescents diagnosed with PFP ages 15-19 yr were recruited from schools. The control group consisted of 29 age-matched healthy female adolescents. Bipolar surface electrodes were placed on vastus medialis and vastus lateralis, and an electronic knee goniometer was placed at the knee to collect knee flexion/extension kinematics. The participants walked down a stairway consisting of 24 steps at their normal pace. Sample entropy was used to quantify the complexity of the time series from surface electromyography and kinematics during the stance phase. Self-reported clinical status was assessed by the KOOS and the maximal quadriceps torque measured using strap-mounted handheld dynamometry. RESULTS: Female adolescents with PFP were characterized by altered neuromuscular knee control during stair descent, lower maximal quadriceps torque, and poorer KOOS scores across all five domains. Furthermore, a positive association was found between the complexity of surface electromyography from vastus lateralis and self-reported pain determined by KOOSpain, indicating larger impairments in neuromuscular knee control among those with the highest pain levels. CONCLUSIONS: The current findings show that female adolescents with PFP are characterized by altered neuromuscular control of the knee during stair descent and lower maximal quadriceps torque. These results suggest that rehabilitation is needed and should focus on restoring neuromuscular control and muscle strength.

Rathleff MS; Samani A; Olesen JL; Roos EM; Rasmussen S; Christensen BH; Madeleine P

2013-09-01

150

Operation of Control Rod Driving Mechanism controller at HANARO  

Energy Technology Data Exchange (ETDEWEB)

HANARO (High flux Advanced Neutron Application Reactor) achieved its first critical operation in 1995. Recently, there has been fast developments in the field of electronics. Many manufacturers of I and C components have disappeared or merged with the other companies. The suppliers of the control systems of the CRDM (Control Rod Driving Mechanism) at HANARO have disappeared. Therefore, we needed to change the control system of the CRDM since we cannot be provided with maintenance any longer. In this paper, we investigated the operation of the control system of the CRDM when the controller and motor driver are changed.

Gyu, Doo Seung; Woo, Lee Min; San, Choe Yeong; Kyoo, Kim Hyung [KAERI, Daejeon (Korea, Republic of)

2012-10-15

151

Autoimmune disorders of the neuromuscular junction  

Directory of Open Access Journals (Sweden)

Full Text Available The neuromuscular junction (NMJ) is a specialized synapse with a complex structural and functional organization. It is a target for a variety of immunological disorders and these diseases usually respond well to immunotherapies. The understanding of the immunological basis of myasthenia gravis, the most common neuromuscular junction disorder, has improved in the recent years. Most patients have antibodies to the acetylcholine receptor (AChR), but around 10% have AChR antibodies that are only identified by novel methods, and up to 5% have muscle-specific kinase antibodies which define a different subgroup of myasthenia. The spectrum of antibodies and their pathophysiological aspects are being elucidated. Even though less common, Lambert Eaton myasthenic syndrome (LEMS) is important to recognize. The abnormality in LEMS is a presynaptic failure to release enough packets of ACh, caused by antibodies to the presynaptic voltage-gated calcium channels. More than half these patients have a small cell carcinoma of lung. Acquired neuromyotonia (NMT) is a condition associated with muscle hyperactivity. Clinical features include muscle stiffness, cramps, myokymia, pseudomyotonia and weakness. The immune mechanisms of acquired NMT relate to loss of voltage-gated potassium channel function. This review will focus on the important recent developments in the immune-mediated disorders of the NMJ.

Vincent Angela

2008-01-01

152

Damper mechanism for nuclear reactor control elements  

International Nuclear Information System (INIS)

A damper mechanism which provides a nuclear reactor control element decelerating function at the end of the scram stroke is described. The total damping function is produced by the combination of two assemblies, which operate in sequence. First, a tapered dashram assembly decelerates the control element to a lower velocity, after which a spring hydraulic damper assembly takes over to complete the final damping. 3 claims, 2 figures

1976-01-01

153

Mechanical components design for PWR - control rod drive mechanism  

International Nuclear Information System (INIS)

The Control Rod Drive Mechanism (CRDM) is usually - a high precision - equipment incorporating mechanical and electrical components designed to move the control rods. The 'control rods' refer to all rods or assemblies that are moved to assess the performance of the reactor. The CRDM here presented is the Nut and Lead Screw type. This type is basically a power screw type magnetically coupled to a slow speed reluctance electric motor that provides a means of axially positioning the movable fuel assemblies in the reactor core for purpose of controlling core reactivity. A helically threaded lead screw assembly, comprising one element of power screw, is attached to a movable fuel assemblies. The CRDM usually has closer and more consistent contact with environment peculiar to the reactor than has only other machinery component. This environment includes not only the radiation field of the reactor, but also the temperature, pressure and chemical properties associated with the material used as the coolant for reactor fuel. Specific and special materials are needed because of the above mentioned application. Due to the importance of the above described CRDM functions, this paper will also consider the nuclear functions and their safety classes as well as the CRDM nuclear design criteria. (author)

2002-01-01

154

Control rod drive mechanism vent valve assembly  

International Nuclear Information System (INIS)

The invention relates generally to a device for closing a tubular object and more particularly to a device having venting means incorporated therein and used for closing a control rod drive mechanism which is installed on a nuclear reactor. A ball valve that is capable of performing the necessary function is described

1979-10-24

155

Voltage instability: Mechanisms and control strategies  

Energy Technology Data Exchange (ETDEWEB)

One of the main objectives in operating an electric power system is to maintain a proper voltage level throughout a system. Failure to do so can lead to equipment damage and blackout. The article discusses the nonlinear aspects of power systems, with emphasis on voltage instability. It provides an overview of the state-of-the-art on the analysis and control of voltage dynamics. Dynamic mechanisms and control strategies are discussed from both theoretical and practical standpoints. The remedial controls implemented in the Puget Sound region of the Pacific Northwest indicate the practical significance of the research area.

Vu, K.T. [ABB Transmission Technology Inst., Raleigh, NC (United States). Power Systems Center; Liu, C.C. [Univ. of Washington, Seattle, WA (United States); Taylor, C.W. [Bonneville Power Administration, Portland, OR (United States); Jimma, K.M. [Puget Sound Power and Light Co., Bellevue, WA (United States)

1995-11-01

156

Neuromuscular dressing effects: a literature review  

Directory of Open Access Journals (Sweden)

Full Text Available The kinesio taping is a technique that was created in 1979 by Doctor Kenzo Kase I’m looking through it that could generate a new therapeutic option to control pain, improve athletic performance and reduce the impact of musculoskeletal disorders. From the Sydney 2000 Olympic Games, this technique as a therapeutic alternative PTO and is composed of health professionals in the field of sport and physical rehabilitation.Objetive: This article aims to identify theoretical approaches on the bandage neuromuscular. Material and methods: held today, for which conducted a literature search of databases such as como Proquest, Ovid, Cochraine, PEDro, Journal of Orthopedic and Sports Physical, Sciencedirect, Pubmed y Literatura Latinoamericana y del Caribe en Ciencias de la Salud (Lilacs).The paper proposes a scheme of contextualization of the current landscape of the use and effects of kinesio taping in the management of different pathologies of the musculo-skeletal system in sports. Conclusion: it is concluded that currently many health professionals, and take the neuromuscular bandage a good therapeutic option in the management of diseases affecting the human body is investigated and every day more about the subject, which makes these new therapeutic methods to acquire a scientific value and transcends knowledge.

Calero PA; Cañón GA

2012-01-01

157

Dynamic neuromuscular stabilization & sports rehabilitation.  

UK PubMed Central (United Kingdom)

UNLABELLED: Dynamic neuromuscular (core) stability is necessary for optimal athletic performance and is not achieved purely by adequate strength of abdominals, spinal extensors, gluteals or any other musculature; rather, core stabilization is accomplished through precise coordination of these muscles and intra-abdominal pressure regulation by the central nervous system. Understanding developmental kinesiology provides a framework to appreciate the regional interdependence and the inter-linking of the skeleton, joints, musculature during movement and the importance of training both the dynamic and stabilizing function of muscles in the kinetic chain. The Dynamic Neuromuscular Stabilization (DNS) approach provides functional tools to assess and activate the intrinsic spinal stabilizers in order to optimize the movement system for both pre-habilitation and rehabilitation of athletic injuries and performance. LEVEL OF EVIDENCE: 5.

Frank C; Kobesova A; Kolar P

2013-02-01

158

Control rod holding mechanism in reactor  

Energy Technology Data Exchange (ETDEWEB)

The present invention concerns a control rod holding mechanism in an FBR type reactor. The control rod holding mechanism comprises in combination an electromagnet having a bisected structure of an iron core and a coil at the lower end of a driving shaft, and a control rod is held under suspension or detached by means of the electromagnet. The feature of the present invention is that the adsorption surface of the both cores of the electromagnet has a spherical structure. Since the control rod is positioned in the reactor core coolants, it undergoes a lateral force due to fluid vibrations. Since the control rod is long, a great bending moment is applied. However, since the adsorption surface in both cores of the electromagnets has the spherical structure in the present invention, even if the bending moment is applied, the bending stress is absorbed by the slip of the adsorption surface. Further, since the gap of the adsorption surface is not changed in this case, the magnetic attraction force is not reduced. Accordingly, the control rod is hardly detached by the horizontal bending stress. In view of the above, there is no worry that the electromagnet is detached during ordinary operation. (I.S.).

Kamei, Mitsuru; Gunji, Minoru; Saito, Makoto.

1990-03-29

159

Neuromuscular Disease Descriptions  

Science.gov (United States)

... any underlying respiratory or heart problems. Peripheral motor neuron diseases (involving muscle-controlling nerve cells of the ... Often associated with diabetes and heart disease. Motor neuron diseases (involving nerve cells in the spinal cord) ...

160

Neuromuscular ultrasound in common entrapment neuropathies.  

UK PubMed Central (United Kingdom)

Neuromuscular ultrasound involves the use of high-resolution ultrasound to image the peripheral nervous system of patients with suspected neuromuscular diseases. It complements electrodiagnostic studies well by providing anatomic information regarding nerves, muscles, vessels, tendons, ligaments, bones, and other structures that cannot be obtained with nerve conduction studies and electromyography. Neuromuscular ultrasound has been studied closely over the past 10 years and has been used most often in the assessment of entrapment neuropathies. This review focuses on the use of neuromuscular ultrasound in 4 of the most common entrapment neuropathies: carpal tunnel syndrome, ulnar neuropathy at the elbow and wrist, and fibular neuropathy at the knee. © 2013 Wiley Periodicals, Inc.

Cartwright MS; Walker FO

2013-05-01

 
 
 
 
161

Hydraulic system for controlling mechanized timbering  

Energy Technology Data Exchange (ETDEWEB)

The hydraulic system for controlling mechanized timbering contains a hydraulic winch whose rodfree cavity is connected by a main to the rod cavity of the hydraulic cylinder of the stand, while the rod-free cavity of the latter is connected to the pressure and overflow hydraulic lines through a support block. To improve operation, the main has an additional support block made in the form of a pressure gate valve and hydraulic lock installed in series whose control cavity is connected to the rod-free cavity of the hydraulic cylinder of the stand.

Livshits, V.I.; Fomin, V.I.; Nikolayev, G.V.; Podkorytov, Ye.I.

1980-04-30

162

Mechanically controllable break junctions for molecular electronics.  

UK PubMed Central (United Kingdom)

A mechanically controllable break junction (MCBJ) represents a fundamental technique for the investigation of molecular electronic junctions, especially for the study of the electronic properties of single molecules. With unique advantages, the MCBJ technique has provided substantial insight into charge transport processes in molecules. In this review, the techniques for sample fabrication, operation and the various applications of MCBJs are introduced and the history, challenges and future of MCBJs are discussed.

Xiang D; Jeong H; Lee T; Mayer D

2013-09-01

163

[Feedback control mechanisms of plant cell expansion  

Energy Technology Data Exchange (ETDEWEB)

We have generated considerable evidence for the significance of wall stress relaxation in the control of plant growth and found that several agents (gibberellin, light, genetic loci for dwarf stature) influence growth rate via alteration of wall relaxation. We have refined our methods for measuring wall relaxation and, moreover, have found that wall relaxation properties bear only a distance relationship to wall mechanical properties. We have garnered novel insights into the nature of cell expansion mechanisms by analyzing spontaneous fluctuations of plant growth rate in seedlings. These experiments involved the application of mathematical techniques for analyzing growth rate fluctuations and the development of new instrumentation for measuring and forcing plant growth in a controlled fashion. These studies conclude that growth rate fluctuations generated by the plant as consequence of a feedback control system. This conclusion has important implications for the nature of wall loosening processes and demands a different framework for thinking about growth control. It also implies the existence of a growth rate sensor.

Cosgrove, D.J.

1992-01-01

164

Computed tomography of muscles in neuromuscular disease  

International Nuclear Information System (INIS)

137 patients with neuromuscular diseases were studied by CT scan. Four levels were chosen: mid-calf, mid-thigh, pelvic girdle, and spinal muscles. The scans were compared with normal control scans taken from the same sites. The patients were divided into those with myogenic diseases and those with neurogenic diseases. Of the 102 patients with myogenic changes, 17 had X-linked dystrophy, 13 had facio-scapulo-humeral dystrophy, 22 had limb girdle dystrophy, 19 had myotonic dystrophy, 14 had inflammatory muscle diseases, and 17 had miscellaneous muscular diseases. Of the 35 patients with neurogenic changes, 8 had amyotrophic lateral sclerosis (ALS), 16 had chronic spinal amyotrophies, 9 had peripheral neuropathies, and 2 had Friedreich's disease. The analysis of muscles changes (volume, outline, density) was established on the following muscles: tibialis anterior, peroneus, soleus, gastrocnemius mediale, gastrocnemius laterale, quadriceps, semitendinosus, semimembranosus, sartorius, adductor, gracilis, gluteus, spine extensors, and psoas

1986-01-01

165

Computed tomography of skeletal muscles in neuromuscular disease  

Energy Technology Data Exchange (ETDEWEB)

CT-documentation of skeletal muscular lesions caused by neuromuscular diseases implies an essential contribution to conventional techniques in the macroscopic field. Size, distribution and degree of lesions as well as compensatory mechanisms are proved thereby. We report about the different effects on muscle appearance referring to 106 patients of our own experience in amyotrophic lateral sclerosis, spinal muscular atrophy, poliomyelitis, polyradiculitis, polyneuropathy as well as peripheral traumatic nerve lesions.

Rodiek, S.O.; Kuether, G.

1985-06-01

166

Computed tomography of skeletal muscles in neuromuscular disease  

International Nuclear Information System (INIS)

CT-documentation of skeletal muscular lesions caused by neuromuscular diseases implies an essential contribution to conventional techniques in the macroscopic field. Size, distribution and degree of lesions as well as compensatory mechanisms are proved thereby. We report about the different effects on muscle appearance referring to 106 patients of our own experience in amyotrophic lateral sclerosis, spinal muscular atrophy, poliomyelitis, polyradiculitis, polyneuropathy as well as peripheral traumatic nerve lesions. (orig.)

1985-01-01

167

[Dysimmune neuromuscular disorders: diagnostic challenges and new ways of management].  

UK PubMed Central (United Kingdom)

This review describes some dysimmune neuromuscular disorders and their recent management: syndrome of peripheral nerve hyperexcitability (treatment of cramps, immunosuppressors); Guillain-Barré syndrome (new mechanisms and consensus treatment); chronic inflammatory demyelinating polyradiculoneuropathy (new indication for the use of pulse dexamethasone, new scores of activity); importance of subcutaneous immunoglobulin in multifocal motor neuropathy and of infusions of rituximab in myasthenia gravis; new entities in myositis and their treatment.

Lalive PH; Du Pasquier RA; Chizzolini C; Kuntzer T

2013-05-01

168

Mechanical control of tissue-engineered bone.  

UK PubMed Central (United Kingdom)

ABSTRACT: Bone is a load-bearing tissue and physical forces play key roles in the development and maintenance of its structure. Mechanical cues can stimulate the expression of an osteogenic phenotype, enhance matrix and mineral deposition, and influence tissue organization to improve the functional outcome of engineered bone grafts. In recent years, a number of studies have investigated the effects of biophysical forces on the bone formation properties of osteoprogenitor cells. The application of physiologically relevant stimuli to tissue-engineered bone may be determined through observation and understanding of forces to which osteoblasts, osteoclasts, and osteocytes are exposed in native bone. Subsequently, these cues may be parameterized and their effects studied in well-defined in vitro systems. The osteo-inductive effects of three specific mechanical cues - shear stress, substrate rigidity, and nanotopography - on cells cultured in monolayer or in three-dimensional biomaterial scaffolds in vitro are reviewed. Additionally, we address the time-dependent effects of mechanical cues on vascular infiltration and de novo bone formation in acellular scaffolds implanted into load-bearing sites in vivo. Recent studies employing cutting-edge advances in biomaterial fabrication and bioreactor design have provided key insights into the role of mechanical cues on cellular fate and tissue properties of engineered bone grafts. By providing mechanistic understanding, future studies may go beyond empirical approaches to rational design of engineering systems to control tissue development.

Hung BP; Hutton DL; Grayson WL

2013-01-01

169

Facial Nerve Monitoring under Neuromuscular Blockade  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The characteristics of facial nerve electromyography at various levels of neuromuscular blockade are unclear. Partial blockade is well known to facilitate anesthetic safety and management. However, the use of neuromuscular blockage in many skull base procedures is avoided to allow intraoperative fac...

Hester, T. Oma; Hasan, Akbar; McDonnell, Francis; Valentino, Joseph; Jones, Raleigh

170

Stirling engine control mechanism and method  

Energy Technology Data Exchange (ETDEWEB)

A reciprocating-to-rotating motion conversion and power control device for a Stirling engine includes a hub mounted on an offset portion of the output shaft for rotation relative to the shaft and for sliding motion therealong which causes the hub to tilt relative to the axis of rotation of the shaft. This changes the angle of inclination of the hub relative to the shaft axis and changes the axial stroke of a set of arms connected to the hub and nutating therewith. A hydraulic actuating mechanism is connected to the hub for moving its axial position along the shaft. A balancing wheel is linked to the hub and changes its angle of inclination as the angle of inclination of the hub changes to maintain the mechanism in perfect balance throughout its range of motion.

Dineen, John J. (Durham, NH)

1983-01-01

171

Stirling engine control mechanism and method  

Energy Technology Data Exchange (ETDEWEB)

A reciprocating-to-rotating motion conversion and power control device for a Stirling engine includes a hub mounted on an offset portion of the output shaft for rotation relative to the shaft and for sliding motion therealong which causes the hub to tilt relative to the axis of rotation of the shaft. This changes the angle of inclination of the hub relative to the shaft axis and changes the axial stroke of a set of arms connected to the hub and nutating therewith. A hydraulic actuating mechanism is connected to the hub for moving its axial position along the shaft. A balancing wheel is linked to the hub and changes its angle of inclination as the angle of inclination of the hub changes to maintain the mechanism in perfect balance throughout its range of motion. 5 figs.

Dineen, J.J.

1983-02-08

172

Maintenance of BWR control rod drive mechanisms  

International Nuclear Information System (INIS)

[en] Control rod drive mechanism (CRDM) replacement and rebuilding is one of the highest dose, most physically demanding, and complicated maintenance activities routinely accomplished by BWR utilities. A recent industry workshop sponsored by the Oak Ridge National Laboratory, which dealt with the effects of CRDM aging, revealed enhancements in maintenance techniques and tooling which have reduced ALARA, improved worker comfort and productivity, and have provided revised guidelines for CRDM changeout selection. Highlights of this workshop and ongoing research on CRDM aging are presented in this paper

1991-01-01

173

Maintenance of BWR control rod drive mechanisms  

Energy Technology Data Exchange (ETDEWEB)

Control rod drive mechanism (CRDM) replacement and rebuilding is one of the highest dose, most physically demanding, and complicated maintenance activities routinely accomplished by BWR utilities. A recent industry workshop sponsored by the Oak Ridge National Laboratory, which dealt with the effects of CRDM aging, revealed enhancements in maintenance techniques and tooling which have reduced ALARA, improved worker comfort and productivity, and have provided revised guidelines for CRDM changeout selection. Highlights of this workshop and ongoing research on CRDM aging are presented in this paper.

Greene, R.H.

1991-01-01

174

Pneumatic, PLC Controlled, Automotive Gear Shifting Mechanism  

Directory of Open Access Journals (Sweden)

Full Text Available In this study, a gear shifting mechanism was designed and applied to make the shifting process faster and less destructible for the driver. The new device must be reliable, has a small dimensions, low construction and maintenance cost. This paper aims to improve gear shifting process using devices as: a manual four speed gear box, four pneumatic double acting cylinders, four pneumatic two position five ways directional control valves, Programmable Logic Controller (PLC) LOGO unit, an electrical motor, an electrical clutch, a belt, two pulleys, limit switches, push buttons, bulbs, a table (holder) and power supply. According to suggested gear_ shifting method the driver can select the transmission gear ratio without moving his hands from the steering wheel by putting the gear shifting push buttons on the steering wheel. Using this method leaves to the driver the excitement of choosing the shifting moment.

Muntaser Momani

2010-01-01

175

Passive cooling of control rod drive mechanisms  

Energy Technology Data Exchange (ETDEWEB)

A method and apparatus are provided for passively cooling the control rod drive mechanisms (CRDMs) in the reactor vessel of a nuclear power plant. Passive cooling is achieved by dispersing a plurality of chimneys within the CRDM array in positions where a control rod is not required. The chimneys induce convective air currents which cause ambient air from within the containment to flow over the CRDM coils. The air heated by the coils is guided into inlets in the chimneys by baffles. The chimney is insulated and extends through the seismic support platform and missile shield disposed above the closure head. A collar of adjustable height mates with plate elements formed at the distal end of the CRDM pressure housings by an interlocking arrangement so that the seismic support platform provides lateral restraint for the chimneys. (Author).

Hankinson, M.F.; Schwirian, R.E.

1992-07-22

176

Development of Mechanical Water Level Controller  

Directory of Open Access Journals (Sweden)

Full Text Available The automatic water level controller is a device designed to regulate automatically the pumping of water to an overhead tank without allowing the water in the tank to be exhausted. The design of this mechanical device was achieved using the Archimedes principle of floatation; having a float which determines the water level in the tank depending on the choice of the minimum (lower) and maximum (upper) level inscribed in the tank. The fundamental attribute of this device is the ease in design, fabrication and mounting at a lower cost. Its testing had shown and proved that it works efficiently with Archimedes’ principle of floatation. This eliminates the frequent human intervention/monitoring of the water level in the overhead tank to control overflow manually, thereby eliminating water and energy wastages.

Akonyi Nasiru Sule; Chinedu Cletus Obinwa; Christian Ebele Okekeze; Eyo Ifreke

2012-01-01

177

Stance control knee mechanism for lower-limb support in hybrid neuroprosthesis  

Directory of Open Access Journals (Sweden)

Full Text Available A hydraulic stance control knee mechanism (SCKM) was developed to fully support the knee against flexion during stance and allow uninhibited motion during swing for individuals with paraplegia using functional neuromuscular stimulation (FNS) for gait assistance. The SCKM was optimized for maximum locking torque for body-weight support and minimum resistance when allowing for free knee motion. Ipsilateral and contralateral position and force feedback were used to control the SCKM. Through bench and nondisabled testing, the SCKM was shown to be capable of supporting up to 70 N-m, require no more than 13% of the torque achievable with FNS to facilitate free motion, and responsively and repeatedly unlock under an applied flexion knee torque of up to 49 N-m. Preliminary tests of the SCKM with an individual with paraplegia demonstrated that it could support the body and maintain knee extension during stance without the stimulation of the knee extensor muscles. This was achieved without adversely affecting gait, and knee stability was comparable to gait assisted by knee extensor stimulation during stance.

Curtis S. To, PhD; Rudi Kobetic, MS; Thomas C. Bulea, MS; Musa L. Audu, PhD; John R. Schnellenberger, MS; Gilles Pinault, MD; Ronald J. Triolo, PhD

2011-01-01

178

Temporal structure of variability reveals similar control mechanisms during lateral stepping and forward walking.  

UK PubMed Central (United Kingdom)

Previous research exploring a lateral stepping gait utilized amount of variability (i.e. coefficient of variation) in the medial-lateral (ML) and anterior-posterior (AP) direction to propose that the central nervous system's active control over gait in any direction is dependent on the direction of progression. This study sought to further explore this notion through the study of the temporal structure of variability which is reflective of the neuromuscular system's organization of the movement over time. The largest Lyapunov exponent (LyE) of the reconstructed attractors for the foot's movement in the AP and ML was calculated. Results revealed that despite the obvious mechanical differences between a lateral stepping gait and typical forward walking, the central nervous system's organization of the movement of the feet is similar in the primary planes of progression, as well as the secondary planes of progression, despite being different anatomical planes during the locomotive tasks. In addition, consistent with previous studies exploring amount of variability, the secondary plane for both locomotive tasks proved to have larger LyE values than the primary plane of progression (F1,9=35.086, p<0.001). This is consistent with less dependency from stride-to-stride in the secondary plane implying increased active control.

Wurdeman SR; Stergiou N

2013-05-01

179

A Biodynamic Feedthrough Model Based on Neuromuscular Principles.  

UK PubMed Central (United Kingdom)

A biodynamic feedthrough (BDFT) model is proposed that describes how vehicle accelerations feed through the human body, causing involuntary limb motions and so involuntary control inputs. BDFT dynamics strongly depend on limb dynamics, which can vary between persons (between-subject variability), but also within one person over time, e.g., due to the control task performed (within-subject variability). The proposed BDFT model is based on physical neuromuscular principles and is derived from an established admittance model---describing limb dynamics---which was extended to include control device dynamics and account for acceleration effects. The resulting BDFT model serves primarily the purpose of increasing the understanding of the relationship between neuromuscular admittance and biodynamic feedthrough. An added advantage of the proposed model is that its parameters can be estimated using a two-stage approach, making the parameter estimation more robust, as the procedure is largely based on the well documented procedure required for the admittance model. To estimate the parameter values of the BDFT model, data are used from an experiment in which both neuromuscular admittance and biodynamic feedthrough are measured. The quality of the BDFT model is evaluated in the frequency and time domain. Results provide strong evidence that the BDFT model and the proposed method of parameter estimation put forward in this paper allows for accurate BDFT modeling across different subjects (accounting for between-subject variability) and across control tasks (accounting for within-subject variability).

Venrooij J; Abbink DA; Mulder M; van Paassen MM; Mulder M; van Helm FC; Bulthoff HH

2013-09-01

180

A case where rocuronium was unable to achieve neuromuscular block immediately after sugammadex administration.  

UK PubMed Central (United Kingdom)

We present a case where immediate muscle relaxation was needed following sugammadex administration. A 72 year-old female underwent surgery for a cerebral artery aneurysm. Upon conclusion of the operation sugammadex (9.3 mg/kg) was administered and the patient was noted to have left hemiplegia. Rocuronium (1.2 mg/kg × 2 doses) was given in order to gain neuromuscular block approximately 25 minutes after sugammadex had been injected. Although TOF monitoring was not utilized in this case and assessing residual muscular block was difficult, spontaneous respirations continued and breathing had to be controlled with sevoflurane and remifentanil. Sugammadex is a potent reversal agent for rocuronium-induced neuromuscular block, however, certain situations require immediate neuromuscular blockade following sugammadex. In this case, rocuronium was unable to induce neuromuscular blockade immediately after sugammadex and that higher concentrations were necessary in addition to intravenous analgesics and inhaled anesthetics.

Sakai Y; Tsutsumi YM; Wakamatsu N; Soga T; Tanaka K; Oshita S

2011-02-01

 
 
 
 
181

A case where rocuronium was unable to achieve neuromuscular block immediately after sugammadex administration.  

Science.gov (United States)

We present a case where immediate muscle relaxation was needed following sugammadex administration. A 72 year-old female underwent surgery for a cerebral artery aneurysm. Upon conclusion of the operation sugammadex (9.3 mg/kg) was administered and the patient was noted to have left hemiplegia. Rocuronium (1.2 mg/kg × 2 doses) was given in order to gain neuromuscular block approximately 25 minutes after sugammadex had been injected. Although TOF monitoring was not utilized in this case and assessing residual muscular block was difficult, spontaneous respirations continued and breathing had to be controlled with sevoflurane and remifentanil. Sugammadex is a potent reversal agent for rocuronium-induced neuromuscular block, however, certain situations require immediate neuromuscular blockade following sugammadex. In this case, rocuronium was unable to induce neuromuscular blockade immediately after sugammadex and that higher concentrations were necessary in addition to intravenous analgesics and inhaled anesthetics. PMID:21372503

Sakai, Yoko; Tsutsumi, Yasuo M; Wakamatsu, Narutomo; Soga, Tomohiro; Tanaka, Katsuya; Oshita, Shuzo

2011-02-01

182

Contrast Loading: Power Output and Rest Interval Effects on Neuromuscular Performance.  

UK PubMed Central (United Kingdom)

Purpose: This study examined the effect of rest interval following the execution of a jump-squat-set with varied external mechanical-power-outputs on repeated jumps height, mechanical power and electromyographic activity. Methods: Twelve male volleyball players executed 6 repeated jumps (RJs) before and at 1, 3, 5, 7, and 10 min following the execution of 6 repetitions of jump-squats with a load: i) that maximized mechanical-power-output (Pmax), ii) 70% of Pmax, iii) 130% of Pmax and iv) control, without extra load. Results: RJs height did not change (p= 0.44) following the jump-squats, mechanical power was higher (p= 0.02) 5 min after the 130%Pmax protocol, and electromyographic activity was higher (p= 0.001) after all exercise protocols compared to control. Irrespective of the time point, however, when the highest RJs set for each individual was analyzed, height, mechanical power and electromyographic activity were higher (p= 0.001 - 0.04) after all loading protocols compared to control with no differences observed (p= 0.53 - 0.72) among loads. Conclusions: Rest duration for a contrast training session should be individually determined regardless of the load and mechanical-power-output used to activate the neuromuscular system. The load that maximizes external mechanical-power-output as compared to a heavier or a lighter load, using the jump-squat exercise, is not more effective for increasing jumping performance afterwards.

Sotiropoulos K; Smilios I; Douda H; Chritou M; Tokmakidis SP

2013-08-01

183

The role of neuromuscular inhibition in hamstring strain injury recurrence.  

UK PubMed Central (United Kingdom)

Hamstring strain injuries are amongst the most common and problematic injuries in a wide range of sports that involve high speed running. The comparatively high rate of hamstring injury recurrence is arguably the most concerning aspect of these injuries. A number of modifiable and nonmodifiable risk factors are proposed to predispose athletes to hamstring strains. Potentially, the persistence of risk factors and the development of maladaptations following injury may explain injury recurrence. Here, the role of neuromuscular inhibition following injury is discussed as a potential mechanism for several maladaptations associated with hamstring re-injury. These maladaptations include eccentric hamstring weakness, selective hamstring atrophy and shifts in the knee flexor torque-joint angle relationship. Current evidence indicates that athletes return to competition after hamstring injury having developed maladaptations that predispose them to further injury. When rehabilitating athletes to return to competition following hamstring strain injury, the role of neuromuscular inhibition in re-injury should be considered.

Fyfe JJ; Opar DA; Williams MD; Shield AJ

2013-06-01

184

Mechanized control system for milled peat production  

Energy Technology Data Exchange (ETDEWEB)

Harvesting periods and evaporability vary during the production season. Efforts are made to reduce the dependency of the yield on weather conditions by making maximum use of them. In order to achieve these goals the Soviet peat production institute VNIITP is researching control methods for the milled production process. The necessary data is obtained from a meteorological station in the production area which possesses the following equipment: a remote-controlled evaporatior (DIP 200), a rain gauge, an anemometer, a psychrometer, sensors indicating the state of the peat stratum (drying) and similar equipment. The evaporation occurring between operations is calculated on the basis of readings from the various equipment and the average moisture of the peat stratum. Evaporation is forecast, but the predictions do not always prove accurate in practice. In a similar fashion an instruction is passed over the radio to perform the necessary technological operation. The calcutlated milling depth is set, which is at present done manually. For the maintenance of the mechanized control system the production plant possesses a mechanized monitoring system for the amount of peat obtained during the milling cycle and its quality, which registers the quantity of peat harvested during each operating phase of the miller. The milling depth for the next milling cycle can be set on the basis of the results obtained. When the weather conditions are stable the milling depth does not have to be altered often during the production season, but if the weather is unstable the milling depth has to be changed 2-3 times, particularly when using the pneumatic harvesting method.

Milto, N.

1985-01-01

185

Controlling mechanisms that determine mercury sorbent effectiveness  

Energy Technology Data Exchange (ETDEWEB)

Coal is now the primary source of anthropogenic mercury emissions in the United States. However, on a worldwide basis, the projected increase in coal usage over the next two decades in China, India, and Indonesia will dwarf the current US coal consumption of 1 billion tons/year. Development of cost-effective mercury control for coal-fired boilers is a primary research need identified in the EPA Mercury Study Report to Congress. A promising approach for mercury control is the injection of an effective sorbent upstream of the particulate control device. Since the amount of mercury in the gas stream from coal combustion is usually in the range of 5 to 10 {micro}g/m{sup 3} (about 1 ppbv), only very small amounts of a sorbent may be necessary. Many of the attempts at using sorbents to control mercury from coal combustion have met with limited success for unexplained reasons. Previous results at the Energy and Environmental Research Center (EERC) identified a major interaction between SO{sub 2} and NO{sub 2} that may be responsible for the poor sorbent performance observed in many tests. Results indicated that a combination of SO{sub 2} and NO{sub 2} will lead to rapid breakthrough of oxidized mercury species. These results also suggest that bench-scale sorbent data collected without SO{sub 2} and NO{sub 2} are likely to be misleading if they are generalized to combustion systems where these gases are almost always present. A better understanding of how various flue gas constituents affect mercury control will be critical to the development of effective sorbents. This paper presents additional data on concentration effects of NO{sub 2} and SO{sub 2} that may help to explain the mechanisms by which these gases affect sorbent performance.

Miller, S.J.; Dunham, G.E.; Olson, E.S.; Brown, T.D.

1999-07-01

186

THE ANALYSIS OF NEUROMUSCULAR MECHANISMS IN CHITON  

Digital Repository Infrastructure Vision for European Research (DRIVER)

1. The degree of curvature of the body and of the girdle of a Chiton is determined by the activity of antagonistic muscle groups. At a certain, early stage in the strychninization of a Chiton the reciprocal inhibition involved in the natural use of these muscle groups is reversed, such that extenso...

Crozier, W. J.

187

Programmed cell death: concept, mechanism and control.  

UK PubMed Central (United Kingdom)

Programmed cell death or apoptosis occurs under physiological conditions as a result of physiological effectors. It is a relatively slower process and requires active participation of the cell in the suicidal mechanism. Apoptosis is controlled by precise intrinsic genetic programme and may be induced by almost all those stimuli causing necrosis. The role played by the intensity in determining the death process and the underlying mechanism is imperfectly understood. Morphologically apoptotic cells appear as small condensed body. The chromatin is dense and fragmented, packed into compact membrane-bound bodies together with randomly distributed cell organelles. The plasma membrane loses its characteristic architecture and shows extensive blebbing. It buds off projections so that the whole cell may split into several membrane-bound apoptotic bodies. Significant chemical changes take place in the plasma membrane. This helps in recognition of the apoptotic bodies by phagocytes. At this moment it is unclear if all cells can undergo apoptosis or it is a characteristic of only some tissues which are predisposed to apoptotic death being directly under the control of hormones or growth factors. Experimental studies aimed at comparison of induction of apoptosis in cells of different origin are warranted to elucidate this point. Biochemically a pre-commitment step for induction of death programmation through macromolecular synthesis is essential for most systems. The double-stranded linker DNA between nucleosomes is cleaved at regular inter-nucleosomal sites through the action of a Ca2+, Mg(2+)-sensitive neutral endonuclease. Zinc is a potent inhibitor of the enzyme. Calcium probably plays a key controlling role in activation of the enzyme since prevention of Ca2+ increase prevents endonuclease activation. It is becoming evident that signal transduction through appropriate receptors control the Ca2+ flux in the cells. Most apoptotic cells require synthesis of RNA and proteins. Delay or abrogation of apoptosis by inhibition of macromolecular synthesis is well known. The dying cells show high mRNA levels for several enzymes. Several degradative enzymes become active. Regulatory proteins maintain control over the apoptotic cascade. At the molecular level, search has been initiated for the mammalian equivalents of the cell death (ced) gene. Activation of several specific genes is indicated. Specific expression of cell death-associated gene products (e.g. TRPM-2/SGP-2) has been reported in several unrelated apoptotic cell systems. Sequential induction of c-fos, c-myc and 70 kDa heat shock protein is reported. Studies demonstrate that certain genes must remain in a transcriptionally active demethylated state during programmed cell death. Recent evidences clearly indicate that apoptosis may be positively or negatively modulated by certain genes.(ABSTRACT TRUNCATED AT 400 WORDS)

Sen S

1992-08-01

188

Controlling mechanisms that determine mercury sorbent effectiveness  

Energy Technology Data Exchange (ETDEWEB)

Coal is now the primary source of anthropogenic mercury emissions in the US, accounting for 46%, or 72 tons/year, of the total US Environmental Protection Agency (EPA) estimated 158 tons/year. However, on a worldwide basis, the projected increase in coal usage over the next two decades in China, India, and Indonesia will dwarf the current US coal consumption of 1 billion tons/year. Development of cost-effective mercury control for coal-fired boilers is a primary research need identified in the EPA Mercury Study Report to Congress. A promising approach for mercury control is the injection of an effective sorbent upstream of the particulate control device. Since the amount of mercury in the gas stream from coal combustion is usually in the range of 5 to 10 {micro}g/m{sup 3} (about 1 ppbv), only very small amounts of a sorbent may be necessary. A requirement is that the mercury be tightly bound in the sorbent, not desorbing upon exposure to ambient air or leaching under wet disposal conditions. Many of the attempts at using sorbents to control mercury from coal combustion have met with limited success for unexplained reasons. Recent results at the EERC identified a major interaction between SO{sub 2} and NO{sub 2} that may be responsible for the poor sorbent performance observed in many tests. Results indicate that a combination of SO{sub 2} and NO{sub 2} will lead to rapid breakthrough of oxidized mercury species. These results also suggest that bench-scale sorbent data collected without CO{sub 2} and NO{sub 2} are likely to be misleading if they are generalized to combustion systems where these gases are almost always present. Understanding this mechanism will be critical to the development of better sorbents. This paper presents possible mechanisms that may explain the observed SO{sub 2}-NO{sub 2} effects on sorbent performance and lead to a more effective control approach.

Miller, S.J.; Dunham, G.E.; Olson, E.S.; Brown, T.D.

1999-07-01

189

Efectos del vendaje neuromuscular: una revisión bibliográfica/ Neuromuscular dressing effects: a literature review/ Efeitos neuromusculares de bandages: uma revisão da literatura  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese A kinesio taping é uma técnica que foi criada em 1979 por Dr. Kenzo Kase Estou procurando através dele que poderia gerar uma nova opção terapêutica para controlar a dor, melhorar o desempenho atlético e reduzir o impacto de distúrbios músculo-esqueléticos. Do Sydney 2000 Olympic Games, estatécnica como uma alternativa terapêutica PTO e é composto de profissionais de saúde na área de reabilitação física e esporte. Alvo: Este artigo tem como objetivo ident (more) ificar abordagens teóricas sobre oNeuromuscular curativo. Materiais e métodos: realizou hoje, para o qual realizou uma pesquisa bibliográficados bancos de dados, tais como como Proquest, Ovid, Cochraine, PEDro, Journal of Orthopedic and Sports Physical, Sciencedirect, Pubmed y Literatura Latinoamericana y del Caribe en Ciencias de la Salud (Lilacs). O documento propõe um esquemade contextualização do cenário atual do uso e efeitos de kinesio taping na gestão dasdiferentes patologias do sistema músculo-esquelético no esporte. Conclusões: conclui-se quemuitos profissionais de saúde atualmente, e tomar as vandaje neuromuscular uma boa opção terapêutica no tratamento de doenças que afetam o corpo humano é investigada e cada dia mais sobre o assunto, o que torna esses novos métodosterapêuticos para adquirir um valor científico e transcende o conhecimento. Abstract in spanish El vendaje neuromuscular es una técnica creada en 1979 por el doctor Kenzo Kase, quien buscó proponer una nueva opción terapéutica para controlar el dolor, mejorar el rendimiento deportivo y reducir el impacto de los trastornos musculo-esqueléticos. A partir de los Juegos Olímpicos de Sydney 2000 esta técnica empleada por los profesionales de la salud en el campo del deporte y la rehabilitación física tomó fuerza como alternativa terapéutica. Objetivo: identifi (more) car las aproximaciones teóricas sobre el vendaje neuromuscular realizadas en la actualidad. Materiales y métodos: se llevó a cabo una búsqueda bibliográfica en bases de datos como Proquest, Ovid, Cochraine, PEDro, Journal of Orthopedic and Sports Physical, Sciencedirect, Pubmed y Literatura Latinoamericana y del Caribe en Ciencias de la Salud (Lilacs). El esquema del artículo propone una contextualización del panorama actual del uso y los efectos del vendaje neuromuscular en el campo deportivo y en el manejo de diferentes patologías del sistema musculo-esquelético. Conclusiones: se concluye que actualmente muchos profesionales de la salud toman el vendaje neuromuscular como un buena opción terapéutica en el manejo de patologías que afectan el cuerpo humano, por lo cual cada día se investiga más acerca del tema, otorgando un valor científico a estos nuevos métodos. Abstract in english The kinesio taping is a technique that was created in 1979 by Doctor Kenzo Kase I'm looking through it that could generate a new therapeutic option to control pain, improve athletic performance and reduce the impact of musculoskeletal disorders. From the Sydney 2000 Olympic Games, this technique as a therapeutic alternative PTO and is composed of health professionals in the field of sport and physical rehabilitation. Objetive: This article aims to identify theoretical app (more) roaches on the bandage neuromuscular. Material and methods: held today, for which conducted a literature search of databases such as como Proquest, Ovid, Cochraine, PEDro, Journal of Orthopedic and Sports Physical, Sciencedirect, Pubmed y Literatura Latinoamericana y del Caribe en Ciencias de la Salud (Lilacs). The paper proposes a scheme of contextualization of the current landscape of the use and effects of kinesio taping in the management of different pathologies of the musculo-skeletal system in sports. Conclusion: it is concluded that currently many health professionals, and take the neuromuscular bandage a good therapeutic option in the management of diseases affecting the human body is investigated and every day more about the subject, which makes these new therapeuti

Calero Saa, Pedro Antonio; Cañón Martínez, Gustavo Adolfo

2012-08-01

190

Controlling fugitive emissions from mechanical seals  

International Nuclear Information System (INIS)

This paper reports that enactment of the 1990 Federal Clean Air Amendments will sharply focus efforts in the process industries to reduce fugitive emissions. Moreover, state and local governments may be imposing stricter laws and regulations which will affect allowable fugitive emissions from U.S. refineries and process plants. Plants outside the U.S. have similar concerns. Clearly, mechanical seals for process pumps represent an enormous population and is one category of equipment destined for careful evaluation as a means to control fugitive emissions. Fugitive are unintentional emissions from valves, pumps, flanges, compressors, etc., as opposed to point-source emissions from stacks, vents and flares. Fugitive emissions do not occur as a part of normal plant operations, but result from the effects of: Malfunctions, Age, Lack of proper maintenance, Operator error, Improper equipment specification, Use of inferior technology, and externally caused damage

1992-01-01

191

Controlling fugitive emissions from mechanical seals  

Energy Technology Data Exchange (ETDEWEB)

This paper reports that enactment of the 1990 Federal Clean Air Amendments will sharply focus efforts in the process industries to reduce fugitive emissions. Moreover, state and local governments may be imposing stricter laws and regulations which will affect allowable fugitive emissions from U.S. refineries and process plants. Plants outside the U.S. have similar concerns. Clearly, mechanical seals for process pumps represent an enormous population and is one category of equipment destined for careful evaluation as a means to control fugitive emissions. Fugitive are unintentional emissions from valves, pumps, flanges, compressors, etc., as opposed to point-source emissions from stacks, vents and flares. Fugitive emissions do not occur as a part of normal plant operations, but result from the effects of: Malfunctions, Age, Lack of proper maintenance, Operator error, Improper equipment specification, Use of inferior technology, and externally caused damage.

Adams, W.V. (Durametallic Corp., Kalamazoo, MI (US))

1992-03-01

192

Discrete Mechanics and Optimal Control: an Analysis  

CERN Multimedia

The optimal control of a mechanical system is of crucial importance in many realms. Typical examples are the determination of a time-minimal path in vehicle dynamics, a minimal energy trajectory in space mission design, or optimal motion sequences in robotics and biomechanics. In most cases, some sort of discretization of the original, infinite-dimensional optimization problem has to be performed in order to make the problem amenable to computations. The approach proposed in this paper is to directly discretize the variational description of the system's motion. The resulting optimization algorithm lets the discrete solution directly inherit characteristic structural properties from the continuous one like symmetries and integrals of the motion. We show that the DMOC approach is equivalent to a finite difference discretization of Hamilton's equations by a symplectic partitioned Runge-Kutta scheme and employ this fact in order to give a proof of convergence. The numerical performance of DMOC and its relationsh...

Ober-Bloebaum, S; Marsden, J E

2008-01-01

193

[Sympathetic control mechanisms during general anesthesia  

UK PubMed Central (United Kingdom)

For more than 100 years scientists have studied the sympathetic nervous system and its cardiovascular control mechanisms. Muscle sympathetic activity is the most important direct and rapidly responding variable for evaluation of sympathetic neural outflow. Therefore, anesthesiologists have been interested in the effects of anesthetics on muscle sympathetic activity at rest and during cardiovascular challenges. This review summarizes effects of positive pressure ventilation, intravenous and inhalational anesthetics as well as nitrous oxide on sympathetic muscle outflow. The least depression of both resting sympathetic outflow and its response to challenges is observed following administration of etomidate, ketamine, or a combination of low dose isoflurane/nitrous oxide and opioids. Thus, these anesthetics can be recommended for anesthesia in patients with already activated sympathetic outflow to maintain arterial blood pressure.

Kienbaum P; Peters J

2001-05-01

194

[Sympathetic control mechanisms during general anesthesia].  

Science.gov (United States)

For more than 100 years scientists have studied the sympathetic nervous system and its cardiovascular control mechanisms. Muscle sympathetic activity is the most important direct and rapidly responding variable for evaluation of sympathetic neural outflow. Therefore, anesthesiologists have been interested in the effects of anesthetics on muscle sympathetic activity at rest and during cardiovascular challenges. This review summarizes effects of positive pressure ventilation, intravenous and inhalational anesthetics as well as nitrous oxide on sympathetic muscle outflow. The least depression of both resting sympathetic outflow and its response to challenges is observed following administration of etomidate, ketamine, or a combination of low dose isoflurane/nitrous oxide and opioids. Thus, these anesthetics can be recommended for anesthesia in patients with already activated sympathetic outflow to maintain arterial blood pressure. PMID:11413695

Kienbaum, P; Peters, J

2001-05-01

195

The effects of roxatidine on neuromuscular transmission.  

Science.gov (United States)

We have investigated the effects of the H2 receptor antagonist roxatidine on the neuromuscular transmission by using the sciatic nerve-gastrocnemius muscle preparation of the rat in vivo. Roxatidine, administered by i.v. injection, potentiates the neuromuscular blockade induced by d-tubocurarine, pancuronium and aminoglycoside antibiotic, kanamycin. Moreover, the drug alone is capable of producing a blockade on the preparation stimulated at high frequency. The neuromuscular blockade induced by roxatidine is partially reversed by 4-aminopyridine but not by dimaprit. PMID:7548786

Bossa, R; Chiericozzi, M; Galatulas, I; Salvatore, G; Teli, M; Baggio, G; Castelli, M

196

The effects of roxatidine on neuromuscular transmission.  

UK PubMed Central (United Kingdom)

We have investigated the effects of the H2 receptor antagonist roxatidine on the neuromuscular transmission by using the sciatic nerve-gastrocnemius muscle preparation of the rat in vivo. Roxatidine, administered by i.v. injection, potentiates the neuromuscular blockade induced by d-tubocurarine, pancuronium and aminoglycoside antibiotic, kanamycin. Moreover, the drug alone is capable of producing a blockade on the preparation stimulated at high frequency. The neuromuscular blockade induced by roxatidine is partially reversed by 4-aminopyridine but not by dimaprit.

Bossa R; Chiericozzi M; Galatulas I; Salvatore G; Teli M; Baggio G; Castelli M

1995-03-01

197

Loop control mechanism for scientific processor  

Energy Technology Data Exchange (ETDEWEB)

This patent describes a vector oriented scientific data processing system, a control mechanism for controlling program loops. It comprises: a first plurality of registers for storing a plurality of vector loop parameters; a current vector loop pointer register coupled to the first plurality of registers to select one of the first plurality of registers to provide current vector loop parameters; a second plurality of registers for storing a plurality of element loop parameters; a current element loop pointer register coupled to the second plurality of registers to select one of the second plurality or registers to provide current element loop parameters; a loop manipulation means having an input and an output means, coupled via its input means to be selected register of the first plurality of registers and by its output means to the selected register of the second plurality of registers. The loop manipulation means to provide at its output means an output signal indicative of the length of the loop stored in the selected register of the first plurality of registers; and the selected register of the second plurality of registers to provide an output signal indicative of a selected element in the length of the loop stored in the selected register of the second plurality of registers to provide a system for efficiently pre-computing loop lengths and thereby enhancing the speed of the vector oriented scientific data processing system.

Rusterholz, J.T.; Hamstra, J.R.

1989-09-19

198

Evaluation of neuromuscular activity in patients with obstructive sleep apnea using chin surface electromyography of polysomnography.  

UK PubMed Central (United Kingdom)

BACKGROUND: It is believed that defects in upper airway neuromuscular control play a role in sleep apnea pathogenesis. Currently, there is no simple and non-invasive method for evaluating neuromuscular activity for the purpose of screening in patients with obstructive sleep apnea. This study was designed to assess the validity of chin surface electromyography of routine polysomnography in evaluating the neuromuscular activity of obstructive sleep apnea subjects and probe the neuromuscular contribution in the pathogenesis of the condition. METHODS: The chin surface electromyography of routine polysomnography during normal breathing and obstructive apnea were quantified in 36 male patients with obstructive sleep apnea. The change of chin surface electromyography from normal breathing to obstructive apnea was expressed as the percent compensated electromyography value, where the percent compensated electromyography value = (normal breath surface electromyography - apnea surface electromyography)/normal breath surface electromyography, and the percent compensated electromyography values among subjects were compared. The relationship between sleep apnea related parameters and the percent compensated electromyography value was examined. RESULTS: The percent compensated electromyography value of the subjects varied from 1% to 90% and had a significant positive correlation with apnea hypopnea index (R(2) = 0.382, P < 0.001). CONCLUSIONS: Recording and analyzing chin surface electromyography by routine polysomnography is a valid way of screening the neuromuscular activity in patients with obstructive sleep apnea. The neuromuscular contribution is different among subjects with obstructive sleep apnea.

Yin GP; Ye JY; Han DM; Wang XY; Zhang YH; Li YR

2013-01-01

199

Control mechanisms for a nonlinear model of international relations  

Energy Technology Data Exchange (ETDEWEB)

Some issues of control in complex dynamical systems are considered. The authors discuss two control mechanisms, namely: a short range, reactive control based on the chaos control idea and a long-term strategic control based on an optimal control algorithm. They apply these control ideas to simple examples in a discrete nonlinear model of a multi-nation arms race.

Pentek, A.; Kadtke, J. [Univ. of California, San Diego, La Jolla, CA (United States). Inst. for Pure and Applied Physical Sciences; Lenhart, S. [Univ. of Tennessee, Knoxville, TN (United States). Mathematics Dept.; Protopopescu, V. [Oak Ridge National Lab., TN (United States). Computer Science and Mathematics Div.

1997-07-15

200

Post-junctional interactions between neuromuscular blocking agents and ethanol at the mouse neuromuscular junction.  

UK PubMed Central (United Kingdom)

BACKGROUND AND PURPOSE: Ethanol is known to have both pre-synaptic and post-synaptic effects at a range of loci in the mammalian nervous system, including the neuromuscular junction. However, the effects of ethanol on evoked synaptic transmission have not been previously studied at the mouse neuromuscular junction. Here, we report on the effects of ethanol on evoked neuromuscular transmission and the interaction of ethanol with non-depolarizing blocking drugs. EXPERIMENTAL APPROACH: Electrophysiological techniques to measure synaptic potentials and synaptic currents were employed in this study. KEY RESULTS: Ethanol (?100?mM) produced increases in the amplitudes of both spontaneous and evoked synaptic events. Under conditions in which neuromuscular transmission was blocked by (+)-tubocurarine, ethanol (12-100?mM) produced greater increases in evoked response amplitude than in spontaneous response amplitude recorded in the absence of (+)-tubocurarine. Ethanol (100?mM) did not affect evoked neurotransmitter release in low-calcium/high-magnesium solutions. With respect to the clinically used neuromuscular blocking drugs, ethanol (100?mM) interfered with the blocking action of vecuronium, but not cisatracurium. CONCLUSIONS AND IMPLICATIONS: Under these conditions, the stimulant effect of ethanol on neuromuscular transmission is exclusively on the post-junctional elements, both to enhance transmission through nicotinic receptors and also via interactions with neuromuscular blocking agents. These actions of ethanol on neuromuscular transmission may affect the dosage of neuromuscular blockers required in patients who have imbibed significant amounts of alcohol.

Searl TJ; Silinsky EM

2010-10-01

 
 
 
 
201

Novel antigens at the neuromuscular junction.  

UK PubMed Central (United Kingdom)

Three novel components of neuromuscular junctions have been identified by use of monoclonal antibodies (McAb) against glycoproteins obtained from a mouse neuroblastoma X human dorsal root ganglion cell hybrid line. Antigen distribution was assessed by fluorescent immunohistochemistry on frozen sections of human intercostal muscle counterstained with labeled alpha-bungarotoxin to identify neuromuscular junctions. Antigen SOS 6 stained exclusively in the neuromuscular junction, whereas antigens SOS 5 and SOS 13 were highly enriched in the junction but also stained extrasynaptic regions. These antigens can be distinguished from previously described components of the neuromuscular junction by their molecular weights, insensitivity to collagenase treatment, and solubility in 0.1% Triton X-100. Indirect evidence suggests that these species-specific antigens are located in the postsynaptic muscle membrane, but location in the junctional basal lamina or subsarcolemmal region cannot be excluded.

Moore SE; Hurko O; Walsh FS

1986-01-01

202

American Association of Neuromuscular & Electrodiagnostic Medicine  

Science.gov (United States)

... CareerCenter Marketplace Muscle & Nerve Membership Directory Neuromuscular Junction Corporate Opportunities Foundation for Research & Education American Board of Electrodiagnostic Medicine About the AANEM Vision, Mission & Values Board of Directors Our Members Our Staff Committees ...

203

INFLUÊNCIA DA BANDAGEM NEUROMUSCULAR NO DESEMPENHO DO SALTO VERTICAL  

Directory of Open Access Journals (Sweden)

Full Text Available Diversas modalidades esportivas utilizam o salto vertical como um dos principaismovimentos. Com a maior exigência do desempenho físico no meio esportivo, se faznecessário intervenções que venham a otimizar o desempenho dos indivíduos. ABandagem Neuromuscular consiste em uma fita adesiva que pode ser esticada em até140% do seu tamanho original aderindo facilmente à pele, tendo como objetivo regulartônus muscular, aliviar dor, correção articular. É frequentemente utilizada no âmbitoesportivo com o intuito de otimizar o desempenho dos atletas, embora sem evidênciascientíficas que comprovem sua eficácia. Este estudo propõe-se a verificar se a BandagemNeuromuscular aplicada nos músculos quadríceps e tríceps sural promove a melhora dodesempenho do salto vertical. Foi realizado um ensaio clínico cruzado randomizado, com12 voluntários sedentários, divididos em 2 grupos: grupo controle(CNTRL- sembandagem) e grupo com bandagem (CB), onde eram submetidos a uma série de saltossobre uma plataforma específica para a análise das variáveis (número de saltos, altura,tempo de solo, tempo de voo, potência relativa, potência absoluta) necessárias. Asavaliações foram realizadas nos momentos pré- aplicação, pós 10 minutos, pós 24 horase pós 48 horas. Não houve diferença estatisticamente significativa (p>0,05) nodesempenho do salto vertical, quando comparados os grupos com bandagem e sembandagem. A aplicação da Bandagem Neuromuscular não interferiu na performancemuscular e na resistência a fadiga, mesmo após 48 horas de aplicação.

Matteus Lisandro Arêas Tinoco; Thiago Geovanini de Oliveira Tavares; Anderson Pontes Morales; Felipe Sampaio Jorge

2012-01-01

204

Vibration or Balance Training on Neuromuscular Performance in Osteopenic Women.  

UK PubMed Central (United Kingdom)

Maintaining neuromuscular function in older age is an important topic for aging societies, especially for older women with low bone density who may be at risk of falls and bone fracture. This randomized controlled trial investigated the effect of resistive exercise with either whole-body vibration training (VIB) or coordination/balance training (BAL) on neuromuscular function (countermovement jump, multiple 1-leg hopping, sit-to-stand test). 68 postmenopausal women with osteopenia or osteoporosis were recruited for the study. 57 subjects completed the 9-month, twice weekly, intervention period. All subjects conducted 30 min of resistance exercise each training day. The VIB-group performed additional training on the Galileo vibration exercise device. The BAL-group performed balance training. An "intent-to-treat" analysis showed greater improvement in the VIB-group for peak countermovement power (p=0.004). The mean [95% confidence interval] effect size for this parameter was a + 0.9[0.3 to 1.5] W/kg greater change in VIB than BAL after 9 months. In multiple 1-leg hopping, a significantly better performance in the VIB-group after the intervention period was seen on a "per-protocol" analysis only. Both groups improved in the sit-to-stand test. The current study provides evidence that short-duration whole-body vibration exercise can have a greater impact on some aspects of neuromuscular function in post-menopausal women with low bone density than proprioceptive training.

Stolzenberg N; Belavý DL; Rawer R; Felsenberg D

2013-04-01

205

Brain mechanisms that control sleep and waking  

Science.gov (United States)

This review paper presents a brief historical survey of the technological and early research that laid the groundwork for recent advances in sleep-waking research. A major advance in this field occurred shortly after the end of World War II with the discovery of the ascending reticular activating system (ARAS) as the neural source in the brain stem of the waking state. Subsequent research showed that the brain stem activating system produced cortical arousal via two pathways: a dorsal route through the thalamus and a ventral route through the hypothalamus and basal forebrain. The nuclei, pathways, and neurotransmitters that comprise the multiple components of these arousal systems are described. Sleep is now recognized as being composed of two very different states: rapid eye movements (REMs) sleep and non-REM sleep. The major findings on the neural mechanisms that control these two sleep states are presented. This review ends with a discussion of two current views on the function of sleep: to maintain the integrity of the immune system and to enhance memory consolidation.

Siegel, Jerome

206

Safety control mechanism for pruning machine  

UK PubMed Central (United Kingdom)

A branch pruning machine safety control mechanism is characterized in that a microswitch is installed and fixed in a main handle cavity, aiming at the contact point of the microswitch, the main handle is connected and installed with a main handle button, the outer lateral connection part of the main handle button is movably hinged with the main handle, the inner lateral movable part of the main handle button is movably hinged with a shift lever, the middle pressing part of the shift lever coordinates with the position limiting part of the main handle, in addition, the middle connection part of the shift lever is connected with one end of a flexible shaft, the other end of the flexible shaft is connected with the movable part of a side handle button, the outer lateral connection part of the side handle button is movably hinged on the side handle, the movable part of the shift lever pressingly coordinates with the contact point of the microswitch. The utility model has advantages of saving space, reducing cost, improving safety and reliability, and is suitable for prompting the use on branch pruning machines.

CHENG PEI

207

Spectrum of Cyber threats & Available Control Mechanisms  

Directory of Open Access Journals (Sweden)

Full Text Available The Internet is undoubtedly the largest public data network enabling and facilitating both personal & business communications worldwide. Wireless networking has experienced a tremendous growth becoming an integral part of homes, offices & all type of businesses. It provides many advantages, but it is also coupled with many security threats and alters the organizations overall information security risk profile. Although implementation of technological solution is the usual respond to the wireless security threats and vulnerabilities, wireless security is primarily a management issue. Cyber crime is constantly evolving and the growing increase in the number of threats that use social engineering techniques is causing concern for several businesses. All it takes is for one user to click on a malicious link and a firm’s network can be brought to a grinding halt. But the early days of cyber threats have gone now. Cyber threats have increased in large number. The volume of effect of these attacks has increased tremendously whereas the transaction time has decreased. The sources of attacks and exploitations are difficult to determine within time frames that enable victims to avoid damage, and any defensive measure is likely eventually to fail given the vulnerabilities of most cyber systems and the incapacities of users. In this paper we review different cyber threats and control mechanisms available and how these are affecting the network world.

Vikram Mangla, Dr.S.N.Panda

2013-01-01

208

PICU EXTUBATION FAILURE: THE ROLE OF NEUROMUSCULAR DISORDERS  

Directory of Open Access Journals (Sweden)

Full Text Available ObjectiveNeuromuscular disorders (diseases of the motor unit), can cause respiratory problems such as impaired cough reflex, chest deformity, recurrent pneumonia and acute respiratory failure; these are the worst most common complications of these diseases and the leading cause of death in such patients (1, 2). Their management hence, very often, entails admission to the Pediatric Intensive Care Unit (PICU) (3,4) and during this phase, endotracheal intubation is almost always necessary, to maintain the patency of airways and to apply Positive Pressure Ventilation (PPV). However, endotracheal intubation is always temporary, and its success or failure depends on the timely decision of its termination to restore the normal respiration or to avoid the risk of recurring respiratory failure (5, 6). We designed this study to evaluate the role of neuromuscular disorders in causing extubation failure as compared to that of other risk factors.Materials & MethodsIn an analytical cross-sectional study, the risk factors of reintubation and duration of mechanical ventilation in two groups of 30 patients each, was compared, the first successful extubation and the second with extubation failure.ResultsNeuromuscular disorders (including Spinal Muscular Atrophy, Guillain- Barre' Syndrome, Congenital Myopathies and Muscular Dystrophies) were the main underlying diseases in extubation-failure group (P= 0.0002). Hypercapnia (PaCO2>50mmHg) was shown to be the most common cause of both the first intubation (P=0.001) and reintubation (P=0.004) in the group of patients who failed extubation. The mean duration of intubation and mechanical ventilation was longer in patients with neuromuscular disorders who had extubation failure (P= 0.01).ConclusionThis study showed that, as underlying problems, neuromuscular disorders are the most common causes of prolonged intubation which defeat weaning from the ventilator and result in reintubation by inducing hypercapnia. Therefore the weaning process needs to be done gradually in these patients, and in conjunction with supportive measures, such as close observation for at least for 72 hours following extubation to monitor any possibility of recurrence of hypercapnic respiratory failure.

N. Billan MD,; A.G. Behbahan MD

2007-01-01

209

TOR is required for the retrograde regulation of synaptic homeostasis at the Drosophila neuromuscular junction.  

UK PubMed Central (United Kingdom)

Homeostatic mechanisms operate to stabilize synaptic function; however, we know little about how they are regulated. Exploiting Drosophila genetics, we have uncovered a critical role for the target of rapamycin (TOR) in the regulation of synaptic homeostasis at the Drosophila larval neuromuscular junction. Loss of postsynaptic TOR disrupts a retrograde compensatory enhancement in neurotransmitter release that is normally triggered by a reduction in postsynaptic glutamate receptor activity. Moreover, postsynaptic overexpression of TOR or a phosphomimetic form of S6 ribosomal protein kinase, a common target of TOR, can trigger a strong retrograde increase in neurotransmitter release. Interestingly, heterozygosity for eIF4E, a critical component of the cap-binding protein complex, blocks the retrograde signal in all these cases. Our findings suggest that cap-dependent translation under the control of TOR plays a critical role in establishing the activity dependent homeostatic response at the NMJ.

Penney J; Tsurudome K; Liao EH; Elazzouzi F; Livingstone M; Gonzalez M; Sonenberg N; Haghighi AP

2012-04-01

210

Cotrel-Dubousset instrumentation in neuromuscular scoliosis.  

UK PubMed Central (United Kingdom)

The study design is retrospective. The aim is to describe our experience about the treatment of patients with neuromuscular scoliosis (NMS) using Cotrel-Dubousset instrumentation. Neuromuscular scoliosis are difficult deformities to treat. A careful assessment and an understanding of the primary disease and its prognosis are essential for planning treatment which is aimed at maximizing function. These patients may have pelvic obliquity, dislocation of the hip, limited balance or ability to sit, back pain, and, in some cases, a serious decrease in pulmonary function. Spinal deformity is difficult to control with a brace, and it may progress even after skeletal maturity has been reached. Surgery is the main stay of treatment for selected patients. The goals of surgery are to correct the deformity producing a balanced spine with a level pelvis and a solid spinal fusion to prevent or delay secondary respiratory complications. The instrumented spinal fusion (ISF) with second-generation instrumentation (e.g., Luque-Galveston and unit rod constructs), are until 1990s considered the gold standard surgical technique for neuromuscular scoliosis (NMS). Still in 2008 Tsirikos et al. said that "the Unit rod instrumentation is a common standard technique and the primary instrumentation system for the treatment of pediatric patients with cerebral palsy and neuromuscular scoliosis because it is simple to use, it is considerably less expensive than most other systems, and can achieve good deformity correction with a low loss of correction, as well as a low prevalence of associated complications and a low reoperation rate." In spite of the Cotrel-Dubousset (CD) surgical technique, used since the beginning of the mid 1980s, being already considered the highest level achieved in correction of scoliosis by a posterior approach, Teli et al., in 2006, said that reports are lacking on the results of third-generation instrumentation for the treatment of NMS. Patients with neuromuscular disease and spinal deformity treated between 1984 and 2008 consecutively by the senior author (G.D.G.) with Cotrel-Dubousset instrumentation and minimum 36 months follow-up were reviewed, evaluating correction of coronal deformity, sagittal balance and pelvic obliquity, and rate of complications. 24 patients (Friedreich's ataxia, 1; cerebral palsy, 14; muscular dystrophy, 2; polio, 2; syringomyelia, 3; spinal atrophy, 2) were included. According the evidence that the study period is too long (1984-2008) and that in more than 20 years many things changed in surgical strategy and techniques, all patients were divided in two groups: only hooks (8 patients) or hybrid construct (16 patients). Mean age was 18.1 years at surgery (range 11 years 7 months-max 31 years; in 17 cases the age at surgery time was between 10 and 20 years old; in 6 cases it was between 20 and 30 and only in 1 case was over 30 years old). Mean follow-up was 142 months (range 36-279). The most frequent patterns of scoliosis were thoracic (10 cases) and thoracolumbar (9 cases). In 8 cases we had hypokyphosis, in 6 normal kyphosis and in 9 hyperkyphosis. In 8 cases we had a normal lordosis, in 11 a hypolordosis and in 4 a hyperlordosis. In 1 case we had global T4-L4 kyphosis. In 8 cases there were also a thoracolumbar kyphosis (mean value 24°, min 20°-max 35°). The mean fusion area included 13 vertebrae (range 6-19); in 17 cases the upper end vertebra was over T4 and in 11 cases the lower end vertebra was over L4 or L5. In 7 cases the lower end vertebra was S1 to correct the pelvic obliquity. In 5 cases the severity of the deformity (mean Cobb's angle 84.2°) imposed a preoperative halo traction treatment. There were 5 anteroposterior and 19 posterior-only procedures. In 10 cases, with low bone quality, the arthrodesis was performed using iliac grafting technique while in the other (14 cases) using autologous bone graft obtained in situ from vertebral arches and spinous processes (in all 7 cases with fusion extended until S1, it was augmented with calcium phosphate). The mean correction

Piazzolla A; Solarino G; De Giorgi S; Mori CM; Moretti L; De Giorgi G

2011-05-01

211

Cotrel-Dubousset instrumentation in neuromuscular scoliosis.  

Science.gov (United States)

The study design is retrospective. The aim is to describe our experience about the treatment of patients with neuromuscular scoliosis (NMS) using Cotrel-Dubousset instrumentation. Neuromuscular scoliosis are difficult deformities to treat. A careful assessment and an understanding of the primary disease and its prognosis are essential for planning treatment which is aimed at maximizing function. These patients may have pelvic obliquity, dislocation of the hip, limited balance or ability to sit, back pain, and, in some cases, a serious decrease in pulmonary function. Spinal deformity is difficult to control with a brace, and it may progress even after skeletal maturity has been reached. Surgery is the main stay of treatment for selected patients. The goals of surgery are to correct the deformity producing a balanced spine with a level pelvis and a solid spinal fusion to prevent or delay secondary respiratory complications. The instrumented spinal fusion (ISF) with second-generation instrumentation (e.g., Luque-Galveston and unit rod constructs), are until 1990s considered the gold standard surgical technique for neuromuscular scoliosis (NMS). Still in 2008 Tsirikos et al. said that "the Unit rod instrumentation is a common standard technique and the primary instrumentation system for the treatment of pediatric patients with cerebral palsy and neuromuscular scoliosis because it is simple to use, it is considerably less expensive than most other systems, and can achieve good deformity correction with a low loss of correction, as well as a low prevalence of associated complications and a low reoperation rate." In spite of the Cotrel-Dubousset (CD) surgical technique, used since the beginning of the mid 1980s, being already considered the highest level achieved in correction of scoliosis by a posterior approach, Teli et al., in 2006, said that reports are lacking on the results of third-generation instrumentation for the treatment of NMS. Patients with neuromuscular disease and spinal deformity treated between 1984 and 2008 consecutively by the senior author (G.D.G.) with Cotrel-Dubousset instrumentation and minimum 36 months follow-up were reviewed, evaluating correction of coronal deformity, sagittal balance and pelvic obliquity, and rate of complications. 24 patients (Friedreich's ataxia, 1; cerebral palsy, 14; muscular dystrophy, 2; polio, 2; syringomyelia, 3; spinal atrophy, 2) were included. According the evidence that the study period is too long (1984-2008) and that in more than 20 years many things changed in surgical strategy and techniques, all patients were divided in two groups: only hooks (8 patients) or hybrid construct (16 patients). Mean age was 18.1 years at surgery (range 11 years 7 months-max 31 years; in 17 cases the age at surgery time was between 10 and 20 years old; in 6 cases it was between 20 and 30 and only in 1 case was over 30 years old). Mean follow-up was 142 months (range 36-279). The most frequent patterns of scoliosis were thoracic (10 cases) and thoracolumbar (9 cases). In 8 cases we had hypokyphosis, in 6 normal kyphosis and in 9 hyperkyphosis. In 8 cases we had a normal lordosis, in 11 a hypolordosis and in 4 a hyperlordosis. In 1 case we had global T4-L4 kyphosis. In 8 cases there were also a thoracolumbar kyphosis (mean value 24°, min 20°-max 35°). The mean fusion area included 13 vertebrae (range 6-19); in 17 cases the upper end vertebra was over T4 and in 11 cases the lower end vertebra was over L4 or L5. In 7 cases the lower end vertebra was S1 to correct the pelvic obliquity. In 5 cases the severity of the deformity (mean Cobb's angle 84.2°) imposed a preoperative halo traction treatment. There were 5 anteroposterior and 19 posterior-only procedures. In 10 cases, with low bone quality, the arthrodesis was performed using iliac grafting technique while in the other (14 cases) using autologous bone graft obtained in situ from vertebral arches and spinous processes (in all 7 cases with fusion extended until S1, it was augmented with calcium phosphate). The mean correction

Piazzolla, Andrea; Solarino, G; De Giorgi, S; Mori, C M; Moretti, L; De Giorgi, G

2011-03-15

212

Adaptive mechanically controlled lubrication mechanism found in articular joints.  

UK PubMed Central (United Kingdom)

Articular cartilage is a highly efficacious water-based tribological system that is optimized to provide low friction and wear protection at both low and high loads (pressures) and sliding velocities that must last over a lifetime. Although many different lubrication mechanisms have been proposed, it is becoming increasingly apparent that the tribological performance of cartilage cannot be attributed to a single mechanism acting alone but on the synergistic action of multiple "modes" of lubrication that are adapted to provide optimum lubrication as the normal loads, shear stresses, and rates change. Hyaluronic acid (HA) is abundant in cartilage and synovial fluid and widely thought to play a principal role in joint lubrication although this role remains unclear. HA is also known to complex readily with the glycoprotein lubricin (LUB) to form a cross-linked network that has also been shown to be critical to the wear prevention mechanism of joints. Friction experiments on porcine cartilage using the surface forces apparatus, and enzymatic digestion, reveal an "adaptive" role for an HA-LUB complex whereby, under compression, nominally free HA diffusing out of the cartilage becomes mechanically, i.e., physically, trapped at the interface by the increasingly constricted collagen pore network. The mechanically trapped HA-LUB complex now acts as an effective (chemically bound) "boundary lubricant"--reducing the friction force slightly but, more importantly, eliminating wear damage to the rubbing/shearing surfaces. This paper focuses on the contribution of HA in cartilage lubrication; however, the system as a whole requires both HA and LUB to function optimally under all conditions.

Greene GW; Banquy X; Lee DW; Lowrey DD; Yu J; Israelachvili JN

2011-03-01

213

Eletroestimulação neuromuscular na reabilitação da disfagia orofaríngea Neuromuscular electrical stimulation in the rehabilitation of oropharyngeal dysphagia  

Directory of Open Access Journals (Sweden)

Full Text Available A reabilitação da disfagia orofaríngea ganhou um novo instrumento terapêutico, a eletroestimulação neuromuscular (EENM), sendo que os mais renomados pesquisadores têm estudado a indicação e os resultados desta abordagem. O objetivo deste trabalho foi apresentar revisão bibliográfica sobre a aplicabilidade da EENM na reabilitação da disfagia orofaríngea. Realizou-se amplo levantamento bibliográfico em bases de dados, englobando as duas últimas décadas de pesquisa na área. Este artigo de revisão mostrou que ainda não há consenso sobre o uso da EENM na reabilitação da disfagia. Constatou-se que a maioria dos trabalhos descreveu o uso da EENM de forma isolada, não relatou as técnicas fonoaudiológicas associadas à eletroterapia e utilizou amostras heterogêneas que agrupavam disfagias orofaríngeas mecânicas e neurogênicas. Somente recentemente programas específicos têm sido delineados e testados em populações mais homogêneas.The rehabilitation of oropharyngeal dysphagia has a new therapeutic tool, the neuromuscular electrical stimulation (NMES), and the most renowned researchers have been studying the applicability and the results of this approach. The aim of this study was to present a literature review regarding the applicability of NMES in the rehabilitation of oropharyngeal dysphagia. An extensive literature review was carried out, considering the last two decades of research in the area. The review showed that there is still no consensus on the use of NMES in the rehabilitation of dysphagia. It was found that most studies described the use of NMES in isolation, did not describe the techniques associated with speech-language therapy associated to electrotherapy, and used heterogeneous samples that clustered mechanical and neurogenic oropharyngeal dysphagia. Only recently specific programs have been designed and tested in more homogeneous populations.

Bruno Tavares de Lima Guimarães; Ana Maria Furkim; Roberta Gonçalves da Silva

2010-01-01

214

Eletroestimulação neuromuscular na reabilitação da disfagia orofaríngea/ Neuromuscular electrical stimulation in the rehabilitation of oropharyngeal dysphagia  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese A reabilitação da disfagia orofaríngea ganhou um novo instrumento terapêutico, a eletroestimulação neuromuscular (EENM), sendo que os mais renomados pesquisadores têm estudado a indicação e os resultados desta abordagem. O objetivo deste trabalho foi apresentar revisão bibliográfica sobre a aplicabilidade da EENM na reabilitação da disfagia orofaríngea. Realizou-se amplo levantamento bibliográfico em bases de dados, englobando as duas últimas décadas de p (more) esquisa na área. Este artigo de revisão mostrou que ainda não há consenso sobre o uso da EENM na reabilitação da disfagia. Constatou-se que a maioria dos trabalhos descreveu o uso da EENM de forma isolada, não relatou as técnicas fonoaudiológicas associadas à eletroterapia e utilizou amostras heterogêneas que agrupavam disfagias orofaríngeas mecânicas e neurogênicas. Somente recentemente programas específicos têm sido delineados e testados em populações mais homogêneas. Abstract in english The rehabilitation of oropharyngeal dysphagia has a new therapeutic tool, the neuromuscular electrical stimulation (NMES), and the most renowned researchers have been studying the applicability and the results of this approach. The aim of this study was to present a literature review regarding the applicability of NMES in the rehabilitation of oropharyngeal dysphagia. An extensive literature review was carried out, considering the last two decades of research in the area. (more) The review showed that there is still no consensus on the use of NMES in the rehabilitation of dysphagia. It was found that most studies described the use of NMES in isolation, did not describe the techniques associated with speech-language therapy associated to electrotherapy, and used heterogeneous samples that clustered mechanical and neurogenic oropharyngeal dysphagia. Only recently specific programs have been designed and tested in more homogeneous populations.

Guimarães, Bruno Tavares de Lima; Furkim, Ana Maria; Silva, Roberta Gonçalves da

2010-12-01

215

Research Group Introduction : Mechanical Control Engineering Laboratory, Mechanical Engineering Department, Shibaura Institute of Technology  

Science.gov (United States)

Mechanical Control Engineering Laboratory focuses on the control theory and implementation for the robotic applications. The research themes include network based tele-operation, mobile robots control for network relay, autonomous outdoor mobile robot and biped robot.

??, ?

216

Splicing therapy for neuromuscular disease.  

UK PubMed Central (United Kingdom)

Duchenne muscular dystrophy (DMD) and spinal muscular atrophy (SMA) are two of the most common inherited neuromuscular diseases in humans. Both conditions are fatal and no clinically available treatments are able to significantly alter disease course in either case. However, by manipulation of pre-mRNA splicing using antisense oligonucleotides, defective transcripts from the DMD gene and from the SMN2 gene in SMA can be modified to once again produce protein and restore function. A large number of in vitro and in vivo studies have validated the applicability of this approach and an increasing number of preliminary clinical trials have either been completed or are under way. Several different oligonucleotide chemistries can be used for this purpose and various strategies are being developed to facilitate increased delivery efficiency and prolonged therapeutic effect. As these novel therapeutic compounds start to enter the clinical arena, attention must also be drawn to the question of how best to facilitate the clinical development of such personalised genetic therapies and how best to implement their provision.

Douglas AG; Wood MJ

2013-04-01

217

ORIENTATION CONTROLLER, MECHANICAL ARM, GRIPPER AND COMPONENTS THEREOF  

UK PubMed Central (United Kingdom)

Disclosed are an orientation controller based on a parallelogram linkage, a mechanical arm, an anthropomorphic gripper and components thereof such as mechanical digits suitable for use, for example, in the field of keyhole surgery.

SCHVALB NIR; BEN MOSHE BOAZ; VARDIMON ALON; SHAMUR BARAK

218

Effects of neuromuscular electrostimulation in patients with heart failure admitted to ward  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Neuromuscular electrostimulation has become a promising issue in cardiovascular rehabilitation. However there are few articles published in the literature regarding neuromuscular electrostimulation in patients with heart failure during hospital stay. Methods This is a randomized controlled pilot trial that aimed to investigate the effect of neuromuscular electrostimulation in the walked distance by the six-minute walking test in 30 patients admitted to ward for heart failure treatment in a tertiary cardiology hospital. Patients in the intervention group performed a conventional rehabilitation and neuromuscular electrostimulation. Patients underwent 60 minutes of electrostimulation (wave frequency was 20 Hz, pulse duration of 20 us) two times a day for consecutive days until hospital discharge. Results The walked distance in the six-minute walking test improved 75% in the electrostimulation group (from 379.7 ± 43.5 to 372.9 ± 46.9 meters to controls and from 372.9 ± 62.4 to 500 ± 68 meters to electrostimulation, p Conclusion The neuromuscular electrostimulation group showed greater improvement in the walked distance in the six-minute walking test in patients admitted to ward for compensation of heart failure.

de Araújo Carlos José Soares; Gonçalves Fernanda Souza; Bittencourt Hugo Souza; dos Santos Noélia Gonçalves; Junior Sérgio Vitor Mecca; Neves Júlio Leal Bandeira; Fernandes André Maurício Souza; Junior Roque Aras; dos Reis FranciscoJoséFariasBorges; Guimarães Armênio Costa; Junior ErenaldodeSouzaRodrigues; Carvalho Vitor Oliveira

2012-01-01

219

Coherent, mechanical control of a single electronic spin.  

UK PubMed Central (United Kingdom)

We demonstrate coherent quantum control of a single spin driven by the motion of a mechanical resonator. The motion of a mechanical resonator is magnetically coupled to the electronic spin of a single nitrogen-vacancy center in diamond. Synchronization of spin-addressing protocols to the motion of the driven oscillator is used to fully exploit the coherence of this hybrid mechanical-spin system. We demonstrate applications of this coherent mechanical spin-control technique to nanoscale scanning magnetometry.

Hong S; Grinolds MS; Maletinsky P; Walsworth RL; Lukin MD; Yacoby A

2012-08-01

220

Towards a Unified Representation of Mechanisms for Robotic Control Software  

Directory of Open Access Journals (Sweden)

Full Text Available This article gives an overview of the Mechanism Model paradigm. The mechanism model paradigm provides a framework to modeling mechanisms for robotic control. The emphasis is on the unification of mathematical models of kinematics/dynamics, geometric information and control system parameters for a variety of robotic systems (including serial manipulators, wheeled and legged locomotors), with algorithms that are needed for typical robot control applications.

Antonio Diaz-Calderon; Issa A. D. Nesnas; Hari Das Nayar; Won S. Kim

2008-01-01

 
 
 
 
221

Neuromuscular fatigue and exercise capacity in fibromyalgia syndrome.  

UK PubMed Central (United Kingdom)

OBJECTIVE: To assess quadriceps strength and fatigability by using femoral nerve magnetic stimulation (FNMS) and their relationship to exercise capacity in patients with fibromyalgia syndrome (FMS) and healthy controls. METHODS: Twenty-two women (11 with FMS, 11 controls) performed a maximal incremental cycling test and a quadriceps fatigue test on 2 separate visits. For quadriceps assessment, we used FNMS during and after maximum voluntary contraction (MVC) to evaluate central and peripheral factors of neuromuscular fatigue. Subjects performed sets of 10 intermittent (5 seconds on/5 seconds off) isometric contractions starting at 10% MVC, in 10% MVC increments from one set to another until exhaustion. Neuromuscular fatigue was assessed with FNMS after each set. RESULTS: FMS patients had reduced initial MVC compared to controls (mean ± SD 102 ± 18 versus 120 ± 24 Nm; P < 0.05) without significant impairment of voluntary activation (mean ± SD 93.5% ± 3.0% versus 93.1% ± 3.4%; P = 0.74). During the fatigue task, FMS patients exhibited a greater fall in evoked muscular responses (mean ± SD -26% ± 6% versus -16% ± 8% at set 50% MVC; P < 0.05), but not in MVC (mean ± SD -24% ± 7% versus -19% ± 4% at set 50% MVC; P = 0.12). During the cycling test, FMS patients had lowered maximal exercise capacity and an enhanced rate of perceived exertion (RPE) compared to controls. The percent reduction in evoked muscular responses during the quadriceps fatigue test correlated with maximum oxygen consumption (r = 0.56, P < 0.05) and RPE at submaximal intensity (r = 0.84, P < 0.05) during cycling. CONCLUSION: Greater impairment in muscle contractility is associated with enhanced perception of exertion and reduced maximal exercise capacity in FMS patients. Neuromuscular impairments should be considered as an important factor underlying functional limitations in FMS patients.

Bachasson D; Guinot M; Wuyam B; Favre-Juvin A; Millet GY; Levy P; Verges S

2013-03-01

222

Control mechanism for the upper airway collapse in patients with obstructive sleep apnea syndrome: a finite element study.  

UK PubMed Central (United Kingdom)

Obstructive sleep apnea syndrome (OSAS) is characterized by recurrent collapses of the upper airway, which lead to repetitive transient hypoxia, arousals and finally sleep fragmentation. Both anatomical and neuromuscular factors may play key roles in the pathophysiology of OSAS. The purpose of this paper was to study the control mechanism of OSAS from the mechanical point of view. A three-dimensional finite element model was developed, which not only reconstructed the realistic anatomical structure of the human upper airway, but also included surrounding structures such as the skull, neck, hyoid, cartilage and soft tissues. The respiration process during the normal and apnea states was simulated with the fluid-structure interaction method (FSI) and the computational fluid dynamics method (CFD). The airflow and deformation of the upper airway obtained from the FSI and the CFD method were compared and the results obtained under large negative pressure during an apnea episode were analyzed. The simulation results show that the FSI method is more feasible and effective than the CFD method. The concave configuration of the upper airway may accelerate the collapse of the upper airway in a positive feedback mechanism, which supplies meaningful information for clinical treatment and further research of OSAS.

Huang R; Li X; Rong Q

2013-04-01

223

Control mechanism for the upper airway collapse in patients with obstructive sleep apnea syndrome: a finite element study.  

Science.gov (United States)

Obstructive sleep apnea syndrome (OSAS) is characterized by recurrent collapses of the upper airway, which lead to repetitive transient hypoxia, arousals and finally sleep fragmentation. Both anatomical and neuromuscular factors may play key roles in the pathophysiology of OSAS. The purpose of this paper was to study the control mechanism of OSAS from the mechanical point of view. A three-dimensional finite element model was developed, which not only reconstructed the realistic anatomical structure of the human upper airway, but also included surrounding structures such as the skull, neck, hyoid, cartilage and soft tissues. The respiration process during the normal and apnea states was simulated with the fluid-structure interaction method (FSI) and the computational fluid dynamics method (CFD). The airflow and deformation of the upper airway obtained from the FSI and the CFD method were compared and the results obtained under large negative pressure during an apnea episode were analyzed. The simulation results show that the FSI method is more feasible and effective than the CFD method. The concave configuration of the upper airway may accelerate the collapse of the upper airway in a positive feedback mechanism, which supplies meaningful information for clinical treatment and further research of OSAS. PMID:23483341

Huang, Renhan; Li, Xiping; Rong, Qiguo

2013-03-12

224

Neuromuscular blocking activity of pinnatoxins E, F and G.  

UK PubMed Central (United Kingdom)

Pinnatoxins are produced by dinoflagellates and belong to the cyclic imine family of toxins. They are fast-acting and highly toxic when administered in vivo in rodent bioassays, causing death by respiratory depression within minutes. Studies have revealed that some cyclic imine toxins cause their toxicity by antagonizing both muscle type and heteromeric and homomeric neuronal nicotinic acetylcholine receptors (nAChRs). Pinnatoxins E, F and G all display potent toxicity in in vivo bioassays, with symptoms of toxicity similar to other cyclic imine toxins. However, very little work has been done on the mechanism of action of these pinnatoxin isomers. Thus the aim of the current study was to investigate the rank order of potency and mechanism of action of pinnatoxins E, F and G. The effects of pinnatoxin E, F and G on in vitro rat hemidiaphragm preparations were investigated using twitch tension and electrophysiological techniques to determine the effects of these toxins on cholinergic transmission at the neuromuscular junction. Pinnatoxins E, F and G all produced concentration-dependent reductions in the nerve evoked twitch response of the rat hemidiaphragm, with IC50 values ranging from 11 to 53 nM and a rank order of potency of F > G > E. Only complete washout of pinnatoxin E was evident, with pinnatoxins F and G displaying slow and incomplete washout profiles. Pinnatoxins F and G also reduced the amplitudes of spontaneous miniature endplate potentials and evoked endplate potentials at the neuromuscular junction, without affecting miniature endplate potential frequency or the resting membrane potential of the muscle fibres. These results show that pinnatoxins E, F and G are all potent neuromuscular blocking agents and cause toxicity by acting as antagonists at muscle type nicotinic acetylcholine receptors.

Hellyer SD; Selwood AI; Rhodes L; Kerr DS

2013-10-01

225

Mechanisms of control of gene expression  

Energy Technology Data Exchange (ETDEWEB)

This book examines an array of topics on the regulation of gene expression, including an examination of DNA-protein interactions and the role of oncogene proteins in normal and abnormal cellular responses. The book focuses on the control of mRNA transcription in eykaryotes and delineates other areas including gene regulation in prokaryotes and control of stable RNA synthesis.

Cullen, B.; Gage, L.P.; Siddiqui, M.A.Q.; Skalka, A.M.; Weissbach, H.

1987-01-01

226

Control System Design Automation for Mechanical Systems  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this paper, a user-friendly and comprehensive control system design package called Control System Design Automation (CSDA) is described. The system consists of five main blocks: A requirement interpretation block, a modeling block, an analysis/design block, a database management and knowledge bas...

Maekawa, K; Pang, GKH

227

Finite Element Analysis of Self Destruction Mechanism in a Mechanical Controller  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this study, dynamic behavior of a controller's Self Destruction mechanism has been simulated using 3D-FEM in Adams software and investigated. This paper has been concentrated on high acceleration controller's projectiles. This controller is mechanical and has been placed in top of the projecti...

Kourosh Hasanpour; Mehdi Massah; Mehrdad Poursina; Mehdi Salmani

228

Vecuronium suppresses transmission at the rat phrenic neuromuscular junction by inhibiting presynaptic L-type calcium channels.  

UK PubMed Central (United Kingdom)

BACKGROUND AND OBJECTIVES: The non-depolarizing muscle relaxant vecuronium inhibits contraction by competitive inhibition of postsynaptic acetylcholine receptors (AchRs), which decreases the number of quanta released per impulse in response to 50 Hz stimulation. The specific role of calcium influx through L-type calcium channels is the promotion of endocytosis and vesicle recycling during high-frequency stimulation. Vecuronium also induces four pulse tetanic fade, a proxy measure of decreased quanta release. We examined whether vecuronium suppresses neuromuscular transmission during high-frequency stimulation by inhibiting presynaptic L-type calcium channels. METHODS: Fifty male Sprague-Dawley rats were divided into five treatment groups: unstimulated control group, ?-bungarotoxin (BTX) group, nifedipine group, vecuronium group, and nifedipine plus vecuronium group. Rat phrenic nerve-diaphragm neuromuscular juctions were stimulated at 50 Hz and field excitatory post-synaptic potentials (fEPSPs) were recorded. Expression levels of the presynaptic Ca(2+)-binding, protein synaptotagmin 1, and the presynaptic plasma membrane protein, syntaxin 1, were measured by Western blots. RESULTS: The fEPSPs evoked by 50 Hz stimulus trains were decreased by vecuronium, nifedipine, and by vecuronium plus nifedipine. Nifedipine, an L-type calcium channel blocker, reduced the expression of synaptogamin and syntaxin and blocked the suppressive effect of vecuronium, suggesting that both agents inhibit presynaptic L-type calcium channels. CONCLUSIONS: Vecuronium which blocked L-type calcium channels may suppress activity of the ?(3)?(2) nAChR subunit, which exists in the presynaptic membrane and enhances quantal release. This ?(3)?(2) nAChR-mediated positive feedback effect may be facilitated by L-type Ca(2+) channel activity under high-frequency stimulation. Vecuronium may disrupt this positive feedback cycle, leading to suppression of fEPSPs. Vercuronium may reduce neuromuscular transmission through presynaptic and postsynaptic mechanisms.

Ji F; Han J; Liu B; Wang H; Shen G; Tao J

2013-01-01

229

Mechanisms for leaf control of gas exchange  

Energy Technology Data Exchange (ETDEWEB)

Several mechanisms enable leaf stomata to optimize water loss with respect to carbon gain. Stomatal responses to environmental variation constitute a plant's first and second lines of defense against damaging water deficits. Changes in the concentrations of endogenous growth regulations and their influence on stomata may well be important to both defense strategies.

Mansfield, T.A.; Davies, W.J.

1985-03-01

230

Specific proteolytic cleavage of agrin regulates maturation of the neuromuscular junction  

Digital Repository Infrastructure Vision for European Research (DRIVER)

During the initial stage of neuromuscular junction (NMJ) formation, nerve-derived agrin cooperates with muscle-autonomous mechanisms in the organization and stabilization of a plaque-like postsynaptic specialization at the site of nerve-muscle contact. Subsequent NMJ maturation to the characteristic...

Bolliger, M F; Zurlinden, A; Lüscher, D; Bütikofer, L; Shakhova, O; Francolini, M; Kozlov, S V; Cinelli, P; Stephan, A

231

The influence of gender on neuromuscular pre-activity during side-cutting  

Digital Repository Infrastructure Vision for European Research (DRIVER)

It is well established that female athletes are at increased risk for sustaining ACL injuries in sports, where sudden changes of direction are a frequent movement pattern. The underlying neuromuscular mechanisms related to the elevated ACL injury rate in female athletes has yet to be fully investiga...

Bencke, Jesper; Zebis, Mette K

232

A single-fibre electromyography study of neuromuscular transmission in patients with cluster headache.  

UK PubMed Central (United Kingdom)

BACKGROUND AND PURPOSE: Mutations of CACNA1A, which encodes a neuronal P/Q Ca2+ channel, are present in patients with familial hemiplegic migraine, and possibly in other types of migraine as well. This calcium channel is also involved in neuromuscular transmission. In our previous study we confirmed that the single-fibre electromyography (SFEMG) method can demonstrate a neuromuscular transmission deficit in migraine with aura. The aim of our present study was to estimate the neurotransmitter dysfunction in cluster headache and to compare the results between patients with cluster headache and those with migraine with aura. MATERIAL AND METHODS: We selected 6 patients with cluster headache and 6 patients with migraine with typical aura. SFEMG of the voluntarily activated extensor digitorum communis muscle was performed. RESULTS: The SFEMG results were in the normal range in the cluster headache group and in the healthy controls. Slight neuromuscular transmission disturbances were present in patients with migraine with aura. CONCLUSIONS: The abnormal neuromuscular transmission detectable by SFEMG may reflect a genetically determined dysfunction of the P/Q Ca2+ channels in a group of migraineurs with aura. Conversely, absence of neuromuscular abnormalities in cluster headache patients could be explained by different aetiology not resulting in channelopathy. Single-fibre electromyography could be a helpful tool in clinically questionable cases in differentiating between cluster headache and migraine with aura.

Domitrz I; Gawe? M; Domitrz W; Kostera-Pruszczyk A; Kwieci?ski H

2012-03-01

233

Oil pollution control mechanisms - statutes and regulations  

International Nuclear Information System (INIS)

[en] The purpose of this analysis is to provide a detailed picture of federal statutes and regulations, as well as case law, bearing on oil spill prevention and control. Emphasis has been placed on federal action occurring after a spill, although some effort is directed toward review of prevention statutes and regulations. In-depth consideration is given the control of oil pollution under the Federal Water Pollution Control Act but this analysis also touches lightly upon acts that have a lesser effect on oil pollution control. These acts being: The Refuse Act; The Ports and Waterways Safety Act of 1972; The Outer Continental Shelf Lands Act; The Oil Pollution Act of 1961; The Deepwater Port Act of 1974, and The Fish and Wildlife Coordination Act

1978-01-01

234

Bloqueio neuromuscular residual após o uso de rocurônio ou cisatracúrio Bloqueo neuromuscular residual después del uso de rocuronio o cisatracúrio Residual neuromuscular block after rocuronium or cisatracurium  

Directory of Open Access Journals (Sweden)

Full Text Available JUSTIFICATIVA E OBJETIVOS: O bloqueio neuromuscular residual na sala de recuperação pós-anestésica (SRPA) é um fenômeno que pode aumentar a morbidade pós-operatória, com incidência variando entre 0% e 93%. O objetivo deste estudo foi avaliar a incidência do bloqueio neuromuscular residual na SRPA. MÉTODO: Foram estudados 93 pacientes submetidos à cirurgia geral com o uso de cisatracúrio ou rocurônio. Após a admissão na SRPA foi realizada a monitorização objetiva da função neuromuscular (aceleromiografia - TOF GUARD). O bloqueio neuromuscular residual foi definido como SQE JUSTIFICATIVA Y OBJETIVOS: El bloqueo neuromuscular residual en la sala de recuperación posanestésica (SRPA) es un fenómeno que puede aumentar la morbidez posoperatoria, con incidencia variando entre 0% y 93%. La finalidad de este estudio fue evaluar la incidencia del bloqueo neuromuscular residual en la SRPA. MÉTODO: Fueron estudiados 93 pacientes sometidos a cirugía general con el uso de cisatracúrio o rocuronio. Después de la admisión en la SRPA fue realizada la monitorización objetiva de la función neuromuscular (aceleromiografia - TOF-GUARD). El bloqueo neuromuscular residual fue definido como TOF BACKGROUND AND OBJECTIVES: Residual neuromuscular block in the post-anesthetic recovery unit (PACU) may increase postoperative morbidity from 0% to 93%. This study aimed at evaluating the incidence of residual neuromuscular block in the PACU. METHODS: Participated in this study 93 patients submitted to general anesthesia with cisatracurium or rocuronium. After PACU admission, neuromuscular function was objectively monitored (acceleromyography - TOF GUARD). Residual neuromuscular block was defined as TOF < 0.9. RESULTS: From 93 patients, 53 received cisatracurium and 40 rocuronium. Demographics, procedure length and the use of antagonists were comparable between groups. Residual neuromuscular block was 32% in subgroup C (cisatracurium) and 30% in subgroup R (rocuronium). Residual neuromuscular block was unrelated to dose, age and use of antagonists, but was related to procedure length. In subgroup C, mean procedure length was 135 minutes for patients with neuromuscular block and 161 minutes for patients without (p < 0.029). In subgroup R, mean surgery length was 122 and 150 minutes, respectively (p < 0.039). CONCLUSIONS: Both groups had high incidence of residual neuromuscular block in the PACU. Residual postoperative curarization is still a problem even with new intermediary action neuromuscular blockers. It is highly important to objectively monitor all patients submitted to general anesthesia with neuromuscular blockers.

Bruno Salomé de Morais; Carlos Henrique Viana de Castro; Vera Coelho Teixeira; Alexandre Silva Pinto

2005-01-01

235

Coherent, mechanical control of a single electronic spin  

CERN Multimedia

The ability to control and manipulate spins via electrical, magnetic and optical means has generated numerous applications in metrology and quantum information science in recent years. A promising alternative method for spin manipulation is the use of mechanical motion, where the oscillation of a mechanical resonator can be magnetically coupled to a spins magnetic dipole, which could enable scalable quantum information architectures9 and sensitive nanoscale magnetometry. To date, however, only population control of spins has been realized via classical motion of a mechanical resonator. Here, we demonstrate coherent mechanical control of an individual spin under ambient conditions using the driven motion of a mechanical resonator that is magnetically coupled to the electronic spin of a single nitrogen-vacancy (NV) color center in diamond. Coherent control of this hybrid mechanical/spin system is achieved by synchronizing pulsed spin-addressing protocols (involving optical and radiofrequency fields) to the moti...

Hong, Sungkun; Maletinsky, Patrick; Walsworth, Ronald L; Lukin, Mikhail D; Yacoby, Amir

2012-01-01

236

Neuromuscular effects of sevoflurane in patients with myasthenia gravis.  

UK PubMed Central (United Kingdom)

The current study evaluated the neuromuscular responses following administration of sevoflurane in 14 patients with myasthenia gravis (MG) (I-IIb in Osserman's classification) scheduled for thymectomy and in 11 control patients (ASA I-II) who underwent elective surgery. The electromyographic (EMG) response of the abductor digiti minimi was measured following train-of-four (TOF) stimulation of the ulnar nerve every 20 s. After induction of anesthesia with a combination of 3-4 mg·kg(-1) thiopental and 1-2 ?g·kg(-1) fentanyl with 66% N2O and oxygen, an inspired concentration of 4% sevoflurane was administered via a face mask for 7 min. Anesthesia was maintained during surgery with 66% N2O in oxygen and with 1 minimum alveolar concentration (MAC) of end-tidal concentration of sevoflurane. The T1 (the amplitude of the first response) values decreased more profoundly in the MG patients than in the control patients at the end of surgery (P<0.05). Following administration of 4% sevoflurane for 7 min, the TOFR (the ratio of the fourth TOF to the first response) values revealed depressions greater than 10% of preinhalation values in 11 of 14 MG patients with a marked individual variation. This attenuated response was followed by a further depression of the TOFR values with increasing time of 1 MAC sevoflurane anesthesia. On the other hand, no notable changes were observed in patients with normal neuromuscular functions. The most significant factor that correlated with the depression of the TOFR values induced by 1 MAC sevoflurane was the anti-AchR antibody titers (P=0.029). Our results indicate that MG patients have an increased neuromuscular sensitivity to sevoflurane.

Morita T; Tsukagoshi H; Kurosaki D; Sugaya T; Yoshikawa D; Shimada H

1996-09-01

237

Controlling a mechanical oscillator with a tunable coherent feedback network  

CERN Document Server

We demonstrate a fully cryogenic microwave feedback network composed of distinct superconducting devices interconnected by waveguides and designed to control a mechanical oscillator coupled to one of the devices. The network is partitioned into an electromechanical device to be controlled and a dynamically tunable controller that coherently receives, processes and feeds back continuous microwave signals that modify the dynamics and readout of the mechanical state. While previous electromechanical systems represent some compromise between efficient control and efficient readout of the mechanical state, as set by the electromagnetic decay rate, this flexible controller yields a closed-loop network that can be dynamically and continuously tuned between both extremes much faster than the mechanical response time. We demonstrate that the microwave decay rate may be modulated by at least a factor of 10 at a rate greater than $10^4$ times the mechanical response rate.

Kerckhoff, Joseph; Ku, H S; Kindel, William F; Cicak, Katarina; Simmonds, Raymond W; Lehnert, K W

2012-01-01

238

Alteration of neuromuscular function in squash.  

UK PubMed Central (United Kingdom)

The alteration in neuromuscular function of knee extensor muscles was characterised after a squash match in 10 trained players. Maximal voluntary contraction (MVC) and surface EMG activity of vastus lateralis (VL) and vastus medialis (VM) muscles were measured before and immediately after a 1-h squash match. M-wave and twitch contractile properties were analysed following single stimuli. MVC declined (280.5+/-46.8 vs. 233.6+/-35.4 Nm, -16%; P<0.001) after the exercise and this was accompanied by an impairment of central activation, as attested by decline in voluntary activation (76.7+/-10.4 vs. 71.3+/-9.6%, -7%; P<0.05) and raw EMG activity of the two vastii (-17%; P<0.05), whereas RMS/M decrease was lesser (VL: -5%; NS and VM: -12%; P=0.10). In the fatigued state, no significant changes in M-wave amplitude (VL: -9%; VM: -5%) or duration were observed. Following exercise, the single twitch was characterised by lower peak torque (-20%; P<0.001) as well as shorter half-relaxation time (-13%; P<0.001) and reduced maximal rate of twitch tension development (-23%; P<0.001) and relaxation (-17%; P<0.05). A 1-h squash match play caused peripheral fatigue by impairing excitation-contraction coupling, whereas sarcolemmal excitability seems well preserved. Our results also emphasise the role of central activation failure as a possible mechanism contributing to the torque loss observed in knee extensors. Physical conditioners should consider these effects when defining their training programs for squash players.

Girard O; Micallef JP; Noual J; Millet GP

2010-01-01

239

Cutaneous mechanisms of isometric ankle force control  

DEFF Research Database (Denmark)

The sense of force is critical in the control of movement and posture. Multiple factors influence our perception of exerted force, including inputs from cutaneous afferents, muscle afferents and central commands. Here, we studied the influence of cutaneous feedback on the control of ankle force output. We used repetitive electrical stimulation of the superficial peroneal (foot dorsum) and medial plantar nerves (foot sole) to disrupt cutaneous afferent input in 8 healthy subjects. We measured the effects of repetitive nerve stimulation on (1) tactile thresholds, (2) performance in an ankle force-matching and (3) an ankle position-matching task. Additional force-matching experiments were done to compare the effects of transient versus continuous stimulation in 6 subjects and to determine the effects of foot anesthesia using lidocaine in another 6 subjects. The results showed that stimulation decreased cutaneous sensory function as evidenced by increased touch threshold. Absolute dorsiflexion force error increased without visual feedback during peroneal nerve stimulation. This was not a general effect of stimulation because force error did not increase during plantar nerve stimulation. The effects of transient stimulation on force error were greater when compared to continuous stimulation and lidocaine injection. Position-matching performance was unaffected by peroneal nerve or plantar nerve stimulation. Our results show that cutaneous feedback plays a role in the control of force output at the ankle joint. Understanding how the nervous system normally uses cutaneous feedback in motor control will help us identify which functional aspects are impaired in aging and neurological diseases.

Choi, Julia T; Jensen, Jesper Lundbye

2013-01-01

240

O uso de bloqueadores neuromusculares no Brasil El uso de bloqueadores neuromusculares en Brasil Neuromuscular blockers in Brazil  

Directory of Open Access Journals (Sweden)

Full Text Available JUSTIFICATIVA E OBJETIVOS: Dados estatísticos referentes ao uso de bloqueadores neuromusculares no Brasil são desconhecidos. Este trabalho se propõe a análise estatística desse tópico. MÉTODO: Foram compiladas 831 respostas de um questionário preenchido em parte por anestesiologistas presentes ao 48º Congresso Brasileiro de Anestesiologia em Recife, 2001 e em parte via Internet, por anestesiologistas cujos endereços eletrônicos constam na página da Sociedade Brasileira de Anestesiologia (www.sba.com.br). Foram analisados os seguintes dados: tempo de contato com a especialidade, região onde atuam os anestesiologistas, uso de bloqueadores neuromusculares (BNM) em ordem de preferência, indicações do uso de succinilcolina, uso do monitor da transmissão neuromuscular, critérios para se considerar o paciente descurarizado, uso de neostigmina, forma de administração dos BNM e descrição de complicações observadas. RESULTADOS: A maioria dos anestesiologistas em questão exerce a profissão há mais de 11 anos e o maior número de respostas foi proveniente da região sudeste do Brasil. O BNM mais empregado é o atracúrio, seguido de pancurônio e succinilcolina. A succinilcolina é mais empregada na indução rápida e em crianças (80% e 25% respectivamente). Monitores da transmissão neuromuscular, 53% dos anestesiologistas nunca usam, e como critério de recuperação, 92% consideram o paciente descurarizado mediante sinais clínicos. Em 45% das vezes os profissionais empregam a neostigmina de forma rotineira, e 94% administra os BNM sob forma de bolus. Cerca de 30% registra ter havido complicação decorrente do uso de BNM. As complicações mais apontadas foram o bloqueio prolongado, o broncoespasmo grave e a curarização residual. CONCLUSÕES: O atracúrio é o bloqueador neuromuscular mais empregado no Brasil, há percentual alto de uso da succinilcolina em situações não emergenciais, o uso de monitores da transmissão neuromuscular é raro, e, como um corolário, um percentual significativo de uso de critérios eminentemente clínicos para considerar o paciente descurarizado. Registrou-se que, cerca de 30% dos anestesiologistas teve algum tipo de complicação decorrente do uso desses fármacos.JUSTIFICATIVA Y OBJETIVOS: Dados estadísticos referentes al uso de bloqueadores neuromusculares en Brasil son desconocidos. Este trabajo se propone el análisis estadístico de ese tópico. MÉTODO: Fueron compiladas 831 respuestas de un cuestionario llenado en parte por anestesiologistas presentes al 48º Congreso Brasileño de Anestesiologia en la ciudad de Recife, 2001 y en parte vía Internet, por anestesiologistas cuyas direcciones electrónicas constan en la página de la Sociedad Brasileña de Anestesiologia (www.sba.com.br). Fueron analizados los siguientes datos: tiempo de contacto con la especialidad, región donde actúan los anestesiologistas, uso de bloqueadores neuromusculares (BNM) en orden de preferencia, indicaciones del uso de succinilcolina, uso del monitor de transmisión neuromuscular, criterios para considerar el paciente descurarizado, uso de neostigmina, forma de administración de los BNM y descripción de complicaciones observadas. RESULTADOS: La mayoría de los anestesiologistas en cuestión ejerce la profesión hace más de 11 años y el mayor número de respuestas fue proveniente de la región sudeste de Brasil. El BNM más empleado es el atracúrio, seguido de pancurónio y succinilcolina. La succinilcolina es más empleada en la inducción rápida y en niños (80% y 25% respectivamente). Monitores de la transmisión neuromuscular, 53% de los anestesiologistas nunca usan, y como criterio de recuperación, 92% consideran el paciente descurarizado mediante señales clínicas. En un 45% de las veces los profesionales emplean la neostigmina de forma rutinaria, y 94% administra los BNM bajo forma de bolus. Cerca del 30% registra que tuvieron complicación consecuente del uso de BNM. Las complicaciones más apuntadas fueron el bloqueo prolongado, el broncoespa

Maria Cristina Simões de Almeida

2004-01-01

 
 
 
 
241

O uso de bloqueadores neuromusculares no Brasil/ Neuromuscular blockers in Brazil/ El uso de bloqueadores neuromusculares en Brasil  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese JUSTIFICATIVA E OBJETIVOS: Dados estatísticos referentes ao uso de bloqueadores neuromusculares no Brasil são desconhecidos. Este trabalho se propõe a análise estatística desse tópico. MÉTODO: Foram compiladas 831 respostas de um questionário preenchido em parte por anestesiologistas presentes ao 48º Congresso Brasileiro de Anestesiologia em Recife, 2001 e em parte via Internet, por anestesiologistas cujos endereços eletrônicos constam na página da Sociedade B (more) rasileira de Anestesiologia (www.sba.com.br). Foram analisados os seguintes dados: tempo de contato com a especialidade, região onde atuam os anestesiologistas, uso de bloqueadores neuromusculares (BNM) em ordem de preferência, indicações do uso de succinilcolina, uso do monitor da transmissão neuromuscular, critérios para se considerar o paciente descurarizado, uso de neostigmina, forma de administração dos BNM e descrição de complicações observadas. RESULTADOS: A maioria dos anestesiologistas em questão exerce a profissão há mais de 11 anos e o maior número de respostas foi proveniente da região sudeste do Brasil. O BNM mais empregado é o atracúrio, seguido de pancurônio e succinilcolina. A succinilcolina é mais empregada na indução rápida e em crianças (80% e 25% respectivamente). Monitores da transmissão neuromuscular, 53% dos anestesiologistas nunca usam, e como critério de recuperação, 92% consideram o paciente descurarizado mediante sinais clínicos. Em 45% das vezes os profissionais empregam a neostigmina de forma rotineira, e 94% administra os BNM sob forma de bolus. Cerca de 30% registra ter havido complicação decorrente do uso de BNM. As complicações mais apontadas foram o bloqueio prolongado, o broncoespasmo grave e a curarização residual. CONCLUSÕES: O atracúrio é o bloqueador neuromuscular mais empregado no Brasil, há percentual alto de uso da succinilcolina em situações não emergenciais, o uso de monitores da transmissão neuromuscular é raro, e, como um corolário, um percentual significativo de uso de critérios eminentemente clínicos para considerar o paciente descurarizado. Registrou-se que, cerca de 30% dos anestesiologistas teve algum tipo de complicação decorrente do uso desses fármacos. Abstract in spanish JUSTIFICATIVA Y OBJETIVOS: Dados estadísticos referentes al uso de bloqueadores neuromusculares en Brasil son desconocidos. Este trabajo se propone el análisis estadístico de ese tópico. MÉTODO: Fueron compiladas 831 respuestas de un cuestionario llenado en parte por anestesiologistas presentes al 48º Congreso Brasileño de Anestesiologia en la ciudad de Recife, 2001 y en parte vía Internet, por anestesiologistas cuyas direcciones electrónicas constan en la págin (more) a de la Sociedad Brasileña de Anestesiologia (www.sba.com.br). Fueron analizados los siguientes datos: tiempo de contacto con la especialidad, región donde actúan los anestesiologistas, uso de bloqueadores neuromusculares (BNM) en orden de preferencia, indicaciones del uso de succinilcolina, uso del monitor de transmisión neuromuscular, criterios para considerar el paciente descurarizado, uso de neostigmina, forma de administración de los BNM y descripción de complicaciones observadas. RESULTADOS: La mayoría de los anestesiologistas en cuestión ejerce la profesión hace más de 11 años y el mayor número de respuestas fue proveniente de la región sudeste de Brasil. El BNM más empleado es el atracúrio, seguido de pancurónio y succinilcolina. La succinilcolina es más empleada en la inducción rápida y en niños (80% y 25% respectivamente). Monitores de la transmisión neuromuscular, 53% de los anestesiologistas nunca usan, y como criterio de recuperación, 92% consideran el paciente descurarizado mediante señales clínicas. En un 45% de las veces los profesionales emplean la neostigmina de forma rutinaria, y 94% administra los BNM bajo forma de bolus. Cerca del 30% registra que tuvieron complicación consecuente del uso de BNM. Las complicacione

Almeida, Maria Cristina Simões de

2004-12-01

242

Control of a mechanical gripper with a fuzzy controller; Control de una garra robotizada mediante un controlador borroso  

Energy Technology Data Exchange (ETDEWEB)

A fuzzy logic system is used to control a mechanical gripper. System is based in a NLX230 fuzzy micro controller. Control rules are programmed by a 68020 microprocessor in the micro controller memory. Stress and its derived are used as feedback signals in the control. This system can adapt its effort to the mechanical resistance of the object between the fingers.

Alberdi, J.; Barcala, J.M.; Gamero, E.; Navarrete, J.J.

1995-07-01

243

Control of a mechanical gripper with a fuzzy controller; Control de una garra robotizada mediante un controlador borroso  

Energy Technology Data Exchange (ETDEWEB)

A fuzzy logic system is used to control a mechanical gripper. System is based in a NLX230 fuzzy micro controller. Control rules are programmed by a 68020 microprocessor in the micro controller memory. Stress and its derived are used as feedback signals in the control. This system can adapt its effort to the mechanical resistance of the object between the fingers. (Author)

Alberdi, J.; Barcala, J.M.; Gamero, E.; Navarrete, J.J.

1995-07-01

244

[Mechanisms of the control of appetite  

UK PubMed Central (United Kingdom)

The peripheral control of appetite is effected by two digestive hormones produced by the stomach and intestine. Bombesin, induced by gastric distension, might act as a messenger informing the nervous centres that the subject is satiated. The pharmacological satiating effect of cholecystokinin, probably mediated by the afferent fibres of the vagus nerve, is well established, but its physiological effect has not yet been demonstrated. Centrally, appetite is controlled by neurotransmitters, satiating and orexigenic properties being shared between monoamines, benzodiazepine-receptors and GABA-receptors. Among digestive hormones present in the central nervous system, the most satiating in pharmacological doses seem to be cholecystokinin and calcitonin, but their physiological role remains obscure. Insulin might be the signal informing the hypothalamus on body fat mass. Endorphins exert an orexigenic effect, reversed by naloxone, which is particularly marked in case of stress, in obese subjects and in the presence of highly palatable food. The control of appetite therefore is complex. It cannot be separated from other functions, such as pain and pleasure, which are regulated by intracerebral peptides.

Rampal P

1986-01-01

245

Autoimmune disorders of the neuromuscular junction  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The neuromuscular junction (NMJ) is a specialized synapse with a complex structural and functional organization. It is a target for a variety of immunological disorders and these diseases usually respond well to immunotherapies. The understanding of the immunological basis of myasthenia gravis, the ...

Vincent Angela

246

Novel Mechanism Control Algorithm for Wired Network  

Directory of Open Access Journals (Sweden)

Full Text Available Problem statement: A critical issue in wireless network where the data can hack by the person and we add a novel encryption mechanism to protect the data transfer from client to server and vice versa. Approach: We present a queuing model of a client and server that uses for bulk arrival service. The arrival of data requests is assumed to Markov Poisson Distributed Process (MPDP) and the events are considered in the server for process sharing. We obtained the parameter of service rate, arrival rate, expected waiting time and expected busy period. We also derive the expression for the data value of threshold. Results: The total number of packets request processed, there was no time limit to arrivals, while compared to m/m/1 model. Our model m/m (1,b)/1 was more efficient to find response and request time in between client and server. Conclusions: Our proposed simulation model validated through Java programming.

V. B. Kirubanand; S. Palaniammal

2011-01-01

247

Molecular motors: design, mechanism and control  

CERN Multimedia

Biological functions in each animal cell depend on coordinated operations of a wide variety of molecular motors. Some of the these motors transport cargo to their respective destinations whereas some others are mobile workshops which synthesize macromolecules while moving on their tracks. Some other motors are designed to function as packers and movers. All these motors require input energy for performing their mechanical works and operate under conditions far from thermodynamic equilibrium. The typical size of these motors and the forces they generate are of the order of nano-meters and pico-Newtons, respectively. They are subjected to random bombardments by the molecules of the surrounding aqueous medium and, therefore, follow noisy trajectories. Because of their small inertia, their movements in the viscous intracellular space exhibits features that are characteristics of hydrodynamics at low Reynold's number. In this article we discuss how theoretical modeling and computer simulations of these machines by...

Chowdhury, Debashish

2007-01-01

248

Neurotic, neuromuscular and autonomic nervous form of magnesium imbalance.  

Science.gov (United States)

The nervous form of magnesium imbalance represents the best documented experimental and clinical aspects of magnesium disorders. The nervous form of primary magnesium deficit (MD) in the adult appears as the best descriptive model for analysis of the symptomatology, aetiology, physiopathology, diagnosis and therapy of the most frequent form of MD. Nervous hyperexcitability due to chronic MD in the adult results in a non-specific clinical pattern with associated central and peripheral neuromuscular symptoms, analogous to the symptomatology previously described in medical literature as latent tetany, hyperventilation syndrome, spasmophilia, chronic fatigue syndrome, neurocirculatory asthenia and idiopathic Barlow's disease. On encountering this non-specific pattern, the signs of neuromuscular hyperexcitability are of much greater importance. Trousseau's sign is less sensitive than Chvostek's sign, but their sensitivities are increased by hyperventilation (Von Bondsdorff's test). Examination of the precordial area will be conducted in order to search clinical stigmata of mitral valve prolapse (MVP) which is a frequent dyskinesia due to chronic MD (about a quarter to one-third of cases). The electromyogram (EMG) shows one (or several) trains of autorhythmic activities beating for more than 2 min of one of the three tetanic activities (uniplets, multiplets or 'complex tonicoclonic tracings') during one of the three facilitation procedures: tourniquet-induced ischaemia lasting 10 min. post-ischaemia lasting 10 min after the removal of the tourniquet and hyperventilation over 5 min. A repetitive EMG constitutes the principal mark of nervous hyperexcitability (NHE) due to MD. The echocardiogram (ECC) is the best tool for detecting MVP, the 2-dimensional ECC with pulsed Doppler being more accurate than time-motion ECC. The routine ionic investigations comprise five static tests: plasma and erythrocyte magnesium, plasma calcium and daily magnesiuria and calciuria. An evaluation of magnesium intake is desirable. Normal concentrations of magnesium in blood do not rule out the diagnosis of the nervous form of primary chronic MD. The histograms of MD group reveal Gaussian type magnesaemias with significantly lower means and the constituent elements can be individually hypo- (one-third of cases), normo- (about two-thirds of cases) and even, exceptionally, hyper-magnesaemic. The diagnosis of MD requires an oral magnesium load test. At physiological dose (5 mg of Mg/kg/day), oral magnesium is totally devoid of the pharmacological effects of parenteral magnesium. Corrections of symptomatology by this oral physiological magnesium load is the best proof that it was due to magnesium deficiency. In particular clinical forms, more sophisticated studies may be useful: standard and quantitative electroencephalograms, electropolygraphic studies of afternoon sleep, electronystagmography, optokinetic test, skin conductance reflex, psychometric inventories, standard or monitoring electrocardiogram, treadmill test, other static and dynamic investigations: e.g. ionized free Mg2+, lymphocyte Mg, brain Mg, cerebrospinal Mg, Mg balance, Mg parenteral load test, glucose load, and even radio-isotope study, the only one able to reveal intestinal magnesium hypersecretion. Nervous primary chronic MD progresses by phases of decompensation against a background of latency. Marginal magnesium deficiency, that is to say an insufficient magnesium intake which merely requires simple oral physiological supplementation, is fundamental in the aetiology of primary magnesium deficit. However a constitutional homeostatic lability of the nervous system or of magnesium metabolism such as belonging to the B35 type of HLA group must be involved. Part of the aetiology of this magnesium deficit is a magnesium depletion, where the disorder which induces magnesium deficit is related to a dysregulation of the control mechanisms of magnesium status which requires a more or less difficult PMID:9368238

Durlach, J; Bac, P; Durlach, V; Bara, M; Guiet-Bara, A

1997-06-01

249

Fuzzy Adaptive Sliding Mode Control of Large Erecting Mechanism  

Directory of Open Access Journals (Sweden)

Full Text Available Sincethe large erecting mechanism has nonlinearities, parameter uncertainties andexternal disturbance, it is difficult to realize a model-based sliding modecontrol design. So a fuzzy adaptive sliding mode control scheme which combinedfuzzy control with sliding mode control is proposed to achieve nonlinearcontrol of the erecting mechanism. This control scheme is mainly use the fuzzysystem to approximate the equivalent control of the sliding mode controllerwithout knowing the system dynamic model. And it also releases thetrial-and-error work of establishing the fuzzy inference rules. The update lawsfor the fuzzy tuning parameters and the switch control parameter are derivedbased on the Lyapunov stability analysis. The simulation results show that comparedto the PID control and conventional sliding mode control, the fuzzy adaptivesliding mode control has nicer robustness and more accurate tracking ability,and the stability of the erecting process has improved.

Li Liang; Xie Jian; Huang Jian Zhao

2013-01-01

250

Neuromuscular adaptations to isoload versus isokinetic eccentric resistance training.  

UK PubMed Central (United Kingdom)

PURPOSE: The purpose of this study was to compare neuromuscular adaptations induced by work-matched isoload (IL) versus isokinetic (IK) eccentric resistance training. METHODS: A total of 31 healthy subjects completed a 9-wk IL (n = 11) or IK (n = 10) training program for the knee extensors or did not train (control group; n = 10). The IL and IK programs consisted of 20 training sessions, which entailed three to five sets of eight repetitions in the respective modalities. The amount of work and the mean angular velocity were strictly matched between IL and IK conditions. Neuromuscular tests were performed before and after training and consisted of the assessment of quadriceps muscle strength, muscle architecture (vastus lateralis), EMG activity, and antagonist coactivation. RESULTS: IL, but not IK, eccentric resistance training enhanced eccentric strength at short muscle length (+20%), high-velocity eccentric strength (+15%), muscle thickness (+10%), and fascicle angle measured at rest (+11%; P < 0.05). Agonist EMG activity increased almost similarly for the two modalities, whereas antagonist coactivation was unaffected by training. CONCLUSIONS: IL proved to be more effective than IK training for improving quadriceps muscle strength and structure. It is conjectured that the rapid acceleration of the load in the early phase of IL eccentric movements (i.e., at short muscle lengths), which results in greater torque and angular velocities compared with IK actions, is the main determinant of strength and neuromuscular adaptations to eccentric training. These findings have important consequences for the optimization of IL and IK eccentric exercise for resistance training and rehabilitation purposes.

Guilhem G; Cornu C; Maffiuletti NA; Guével A

2013-02-01

251

MECHANICALLY CONTROLLED HYDRAULIC SYSTEM FOR AN AGRICULTURAL IMPLEMENT  

UK PubMed Central (United Kingdom)

A hydraulic control apparatus for a foldable farm includes first hydraulic control system is used to control weight transfer to ground engaging tools mounted to a stationary and foldable wing frame sections. A second hydraulic system is used to fold and unfold the wing sections. A hydraulic control is provided that interfaces with both hydraulic systems to control sequencing of the functions provided by the first and second hydraulic systems. The first and second hydraulically systems have mechanically controlled valves to control the flow of hydraulic fluid to various lifting, folding, and down pressure cylinders.

YUEN CORY

252

Mechanically Controlled Hydraulic System For An Agricultural Implement  

UK PubMed Central (United Kingdom)

A hydraulic control apparatus for a foldable farm includes first hydraulic control system is used to control weight transfer to ground engaging tools mounted to a stationary and foldable wing frame sections. A second hydraulic system is used to fold and unfold the wing sections. A hydraulic control is provided that interfaces with both hydraulic systems to control sequencing of the functions provided by the first and second hydraulic systems. The first and second hydraulically systems have mechanically controlled valves to control the flow of hydraulic fluid to various lifting, folding, and down pressure cylinders.

YUEN CORY

253

Coupling mechanism of control rod for nuclear reactor  

Energy Technology Data Exchange (ETDEWEB)

Each of control rods inserted in the core of a nuclear reactor is coupled to a control rod driving apparatus for moving the control rod in an axial direction by a coupling mechanism including a gripper formed at a lower end of a driving extension shaft adapted to be driven by the control rod driving apparatus, and a finger mounted at an upper end of the control rod for engagement with the gripper. A cam is located in the interior of the driving extension shaft for bringing the gripper and the finger into and out of engagement with each other for coupling and uncoupling the control rod and the control rod driving apparatus.

Suzuki, T.

1981-09-29

254

Neuromuscular transmission studies in human chronic Chagas' disease/ Estudio de la transmisión neuromuscular en la enfermedad de Chagas crónica humana  

Scientific Electronic Library Online (English)

Full Text Available Abstract in spanish Cincuenta y ocho pacientes con edades entre los 1 y 58 años, con diagnóstico de enfermedad de Chagas crónica fueron estudiados para evaluar la transmisión neuromuscular. Se estimuló en forma supramáxima el nervio cubital a nivel de muñeca, con registro de electrodos de superficie en hipotenar. Dicha estimulación se realizó a 3 Hz durante 2 segundos y 10 Hz durante 1 segundo en condiciones basales, trás 4 minutos de ejercicio mecánico, luego de 4 minutos de ejer (more) cicio mecánico mas isquemia y trás 2 minutos de liberada la isquemia. Se procedió a medir la amplitud del 3, 5, 6 y 10 potencial, que fueron expresados como variación porcentual con respecto al primero al que se le asignó un valor de 100%. Treinta pacientes no evidenciaron diferencias con respecto a la curva obtenida en 20 sujetos controles, 4 mostraron una caida del potencial evocado muscular, 6 una caida del mismo cuando el estímulo se realizó la bajas frecuencias y un incremento cuanto el estímulo fue a altas frecuencias. En los restantes 18 pacientes se observó un incremento del pem. Estos hallazgos sugieren una posible alteración de la transmisión neuromuscular en algunos pacientes que han alcanzado el estadio crónico de la enfermedad de Chagas de probable localización pré y/o post-sináptica. Abstract in english An electrophysiological investigation of the state of the neuromuscular transmission (nmt) was carried out in 58 patients with the diagnosis of chronic Chagas' disease. On repetitive supramaximal nerve stimulation it was found that some patients did not show abnormalities, others had decremental muscle responses, others developed enhancement of the muscle evoked potential amplitudes, while some other patients combined both types of pathological responses. The findings sug (more) gest that some patients with chronic Chagas' disease develop impairement of nmt, though data obtained in this study do not give information about neither the type of impairement nor the localization (pre or postsynaptic, or both) of the damage.

Erro, Marcela Garcia; Genovese, O.; Correale, J.; Sica, R. E. P.

1989-09-01

255

A Lightweight Mechanism to Control Misbehaving  

UK PubMed Central (United Kingdom)

In this paper we address the problem of containingmisbehaving flows at congested routers, by decouplingit from the more complex issue of fair bandwidth sharing.We propose a very lightweight scheme based on aggregatefair packet marking at the network edge followedby simple RIO queueing at the congested network core tocontrol, and penalize misbehaving flows. We develop anew class of AQM-based fair, stateless, aggregate packetmarkers that mark misbehaving flows among an edge aggregate,which are then dropped preferentially at a RIOenabledrouter during congestion. We show, through extensivepacket level simulations and an informal game theoryanalysis, that even with such a simple and stateless scheme,we can effectively penalize and control misbehaving flowsat congested routers, and provide much better performanceto best-effort TCP flows. Since our markers are statelessand operate on edge aggregates, and we do not introduceany complicated AQM algorithm at the network core, ourscheme is extremely easy to deploy. This motivates thefollowing important research question: Can we design alightweight, stateless, edge-marking based architecture thatcan provide global fairness among different flows from differentedge-domains without making significant modificationsto the core routers?I.

Abhimanyu Das; Debojyoti Dutta; Ahmed Helmy

256

Tratamiento farmacológico de las alteraciones neuromusculares en el paciente crítico Pharmacological treatment neuromuscular impairments in critically ill patients  

Directory of Open Access Journals (Sweden)

Full Text Available El empleo de fármacos para tratamiento de las alteraciones neuromusculares que se presentan en el enfermo ingresado en una Unidad de Cuidados Intensivos es prácticamente inexistente. El empleo de inmunoglobulinas por vía venosa para el tratamiento de la polineuropatía del paciente crítico (PPC) no aporta ninguna evidencia para su uso. Más importancia tiene el tratamiento profiláctico, como es el caso de la administración de una perfusión de insulina para prevenir la hiperglucemias que seasocian a un mayor desarrollo de la PPC. Nuevos datos inducen a pensar que el mecanismo protector de esta perfusión, normalizando los niveles de glucosa se hacen modulando una disfunción endotelial y a unos menores niveles de dimetilarginina asimétrica (ADMA). Con respecto a la miopatía del paciente crítico o a los cuadros de bloqueo neuromuscular prolongado, el tratamiento consiste en evitar el empleo de diversos fármacos que se sabe se asocian al desarrollo de estas entidades como son los corticoides, los relajantes musculares y los aminoglucósidos. Por lo que respecta a la parálisis aguda flácida -infección por el virus del oeste del nilo se han comunicado casos anecdóticos de mejoría con el empleo de corticoides o de interferón, pero su tratamiento rutinario queda aún por establecer.The use of drugs for treating neuromuscular impairments that present in the patient admitted to the Intensive Care Unit is virtually inexistent. The use of intravenous immunoglobulins for managing polyneuropathy of the critically ill patient (PCIP) is supported by no evidence. More important is prophylactic therapy, as is the administration of insulin perfusion to prevent hyperglycemia that is associated to increased development of PCIP. New data suggest that the protective mechanism of this perfusion, which normalizes glucose levels, is achieved through the modulation of endothelial dysfunction and lowering levels of asymmetrical di-methyl arginine (ADMA). As for myopathy of the critically ill patient or conditions with prolonged neuromuscular blockade, treatment consists in avoiding the use of several drugs known to be associated with development of these conditions, such as muscle relaxants and aminoglycosides. In relation to acute flaccid paralysis -an infection caused by the Western Nile Virus, anecdotic cases have been reported of improvement with the use steroids or interferon, although routine management remains to be established.

C. Ortiz Leyba

2006-01-01

257

Respiratory management of acute respiratory failure in neuromuscular diseases.  

UK PubMed Central (United Kingdom)

Neuromuscular diseases (NMD) can affect all major respiratory muscles, leading to the development of respiratory failure, which is the most common cause of morbidity and mortality in patients affected by those conditions. Based on the clinical onset of acute respiratory failure (ARF), NMD can be classified into two main categories: 1) slowly progressive NMD with acute exacerbations of chronic respiratory failure, and 2) rapidly progressive NMD with acute episodes of respiratory failure. The most common slowly progressive NMDs, such as motor neuron diseases and inherited myopathies, account for the majority of NMD patients developing chronic neuromuscular respiratory failure at risk of acute exacerbations. Conversely, rapidly progressive NMDs, such as Guillain-Barré syndrome and myasthenic crises, are characterized by a sudden onset of ARF, usually in patients with previously normal respiratory function. The patho-physiological mechanisms responsible for ARF in NMD and the variety and complexity of specific challenges presented by the two main categories of NMD will be analyzed in this review, with the aim of providing clinically relevant suggestions for adequate respiratory management of these patients.

Racca F; Del Sorbo L; Mongini T; Vianello A; Ranieri VM

2010-01-01

258

Respiratory management of acute respiratory failure in neuromuscular diseases.  

Science.gov (United States)

Neuromuscular diseases (NMD) can affect all major respiratory muscles, leading to the development of respiratory failure, which is the most common cause of morbidity and mortality in patients affected by those conditions. Based on the clinical onset of acute respiratory failure (ARF), NMD can be classified into two main categories: 1) slowly progressive NMD with acute exacerbations of chronic respiratory failure, and 2) rapidly progressive NMD with acute episodes of respiratory failure. The most common slowly progressive NMDs, such as motor neuron diseases and inherited myopathies, account for the majority of NMD patients developing chronic neuromuscular respiratory failure at risk of acute exacerbations. Conversely, rapidly progressive NMDs, such as Guillain-Barré syndrome and myasthenic crises, are characterized by a sudden onset of ARF, usually in patients with previously normal respiratory function. The patho-physiological mechanisms responsible for ARF in NMD and the variety and complexity of specific challenges presented by the two main categories of NMD will be analyzed in this review, with the aim of providing clinically relevant suggestions for adequate respiratory management of these patients. PMID:20125073

Racca, F; Del Sorbo, L; Mongini, T; Vianello, A; Ranieri, V M

2009-11-24

259

Man-Machine Interface System for Neuromuscular Training and Evaluation Based on EMG and MMG Signals  

Directory of Open Access Journals (Sweden)

Full Text Available This paper presents the UVa-NTS (University of Valladolid Neuromuscular Training System), a multifunction and portable Neuromuscular Training System. The UVa-NTS is designed to analyze the voluntary control of severe neuromotor handicapped patients, their interactive response, and their adaptation to neuromuscular interface systems, such as neural prostheses or domotic applications. Thus, it is an excellent tool to evaluate the residual muscle capabilities in the handicapped. The UVa-NTS is composed of a custom signal conditioning front-end and a computer. The front-end electronics is described thoroughly as well as the overall features of the custom software implementation. The software system is composed of a set of graphical training tools and a processing core. The UVa-NTS works with two classes of neuromuscular signals: the classic myoelectric signals (MES) and, as a novelty, the myomechanic signals (MMS). In order to evaluate the performance of the processing core, a complete analysis has been done to classify its efficiency and to check that it fulfils with the real-time constraints. Tests were performed both with healthy and selected impaired subjects. The adaptation was achieved rapidly, applying a predefined protocol for the UVa-NTS set of training tools. Fine voluntary control was demonstrated to be reached with the myoelectric signals. And the UVa-NTS demonstrated to provide a satisfactory voluntary control when applying the myomechanic signals.

Ramon de la Rosa; Alonso Alonso; Albano Carrera; Ramon Durán; Patricia Fernández

2010-01-01

260

?????????????????? Brown Adipose Tissue Differentiation and Control Mechanism  

Directory of Open Access Journals (Sweden)

Full Text Available ?????????????????????????(???????????)????????????????????????????????????????????????????????????????????BMP7 (bone morphogenetic proteins 7)???????-??????(transforming growth?TGF-?)????????????????????????????????????????????????????????BMP7??????????????????BMP7??PRDM16?PGC-1??????????????UCP1????????????????????????????????????????????? BMP7?PRDM16 ?????????????????????????????????????????????????–???????????????(?)X-????????(18F-FDG-PET/CT)????????????????????????????????????????????????????????????????????Humans and other mammals have two main adipose tissue depots: white adipose tissue (include visceral- and subcutaneous- white adipose tissue), and brown adipose tissue, each of which possesses unique cell-autonomous properties. In contrast to visceral adipose tissue, which can induce detrimental metabolic ef-fects, subcutaneous white adipose tissue and brown adipose tissue have the potential to benefit metabolism by improving glucose homeostasis and increasing energy consumption. BMP7 (bone morphogenetic proteins7) is one of members of the transforming growth factor-? (TGF-?) superfamily and control multiple key steps of embryonic development and differentiation. In recent studies, people found that BMP7-induced UCP1 ex-pression was markedly diminished in brown preadipocytes deficient in both PRDM16 and PGC (PGC-1? and PGC-1?), it ultimately induces BAT mitochondrial cells in the biological production and cell differentiation. There are two ways in development of brown adipose tissue. These researches indicate the potential to treat obesity and related diseases through activating BMP7 and PRDM16 to produce brown adipose tissue. Re-cently, using 18F-fluorodeoxyglucose (18F-FDG) positron-emission tomographic and computed tomographic (PET-CT) scans showed that adults retain metabolically active BAT depots that can be induced in response to cold and sympathetic nervous system activation. These findings high light BAT as a potenial relevant tar get for pharmacological and gene expression manipulation to combat human obesity. We reviewed the recent re-search progresses of BAT in human and its potential functional significance.

??; ???; ???; ??; ???

2011-01-01

 
 
 
 
261

?????????????????? Brown Adipsoe Tissue Differentiation and Control Mechanism  

Directory of Open Access Journals (Sweden)

Full Text Available ?????????????????????????(???????????)????????????????????????????????????????????????????????????????????BMP7 (bone morphogenetic proteins 7)???????-??????(transforming growth?TGF-?)????????????????????????????????????????????????????????BMP7??????????????????BMP7??PRDM16?PGC-1??????????????UCP1????????????????????????????????????????????? BMP7?PRDM16 ?????????????????????????????????????????????????–???????????????(?)X-????????(18F-FDG-PET/CT)????????????????????????????????????????????????????????????????????Humans and other mammals have two main adipose tissue depots: white adipose tissue (include visceral- and subcutaneous- white adipose tissue), and brown adipose tissue, each of which possesses unique cell-autonomous properties. In contrast to visceral adipose tissue, which can induce detrimental metabolic ef-fects, subcutaneous white adipose tissue and brown adipose tissue have the potential to benefit metabolism by improving glucose homeostasis and increasing energy consumption. BMP7 (bone morphogenetic proteins7) is one of members of the transforming growth factor-? (TGF-?) superfamily and control multiple key steps of embryonic development and differentiation. In recent studies, people found that BMP7-induced UCP1 ex-pression was markedly diminished in brown preadipocytes deficient in both PRDM16 and PGC (PGC-1? and PGC-1?), it ultimately induces BAT mitochondrial cells in the biological production and cell differentiation. There are two ways in development of brown adipose tissue. These researches indicate the potential to treat obesity and related diseases through activating BMP7 and PRDM16 to produce brown adipose tissue. Re-cently, using 18F-fluorodeoxyglucose (18F-FDG) positron-emission tomographic and computed tomographic (PET-CT) scans showed that adults retain metabolically active BAT depots that can be induced in response to cold and sympathetic nervous system activation. These findings high light BAT as a potenial relevant tar get for pharmacological and gene expression manipulation to combat human obesity. We reviewed the recent re-search progresses of BAT in human and its potential functional significance.

??; ???; ???; ??; ???

2011-01-01

262

Control mechanism for a gas-fired water heater  

Energy Technology Data Exchange (ETDEWEB)

A novel electric control mechanism allows gas-fired water heaters to operate efficiently without a pilot burner. The safety ignition circuit responds directly to high gas pressure in the main inlet chamber, thus preventing continuous operation of the igniter.

Charron, J.C.

1981-05-19

263

A Method to Measure the Relationship Between Biodynamic Feedthrough and Neuromuscular Admittance.  

UK PubMed Central (United Kingdom)

Biodynamic feedthrough (BDFT) refers to a phenomenon where accelerations cause involuntary limb motions, which can result in unintentional control inputs that can substantially degrade manual control. It is known that humans can adapt the dynamics of their limbs by adjusting their neuromuscular settings, and it is likely that these adaptations have a large influence on BDFT. The goal of this paper is to present a method that can provide evidence for this hypothesis. Limb dynamics can be described by admittance, which is the causal dynamic relation between a force input and a position output. This paper presents a method to simultaneously measure BDFT and admittance in a motion-based simulator. The method was validated in an experiment. Admittance was measured by applying a force disturbance signal to the control device; BDFT was measured by applying a motion disturbance signal to the motion simulator. To allow distinguishing between the operator's responses to each disturbance signal, the perturbation signals were separated in the frequency domain. To show the impact of neuromuscular adaptation, subjects were asked to perform three different control tasks, each requiring a different setting of the neuromuscular system (NMS). Results show a dependence of BDFT on neuromuscular admittance: A change in neuromuscular admittance results in a change in BDFT dynamics. This dependence is highly relevant when studying BDFT. The data obtained with the proposed measuring method provide insight in how exactly the settings of the NMS influence the level of BDFT. This information can be used to gain fundamental knowledge on BDFT and also, for example, in the development of a canceling controller.

Venrooij J; Abbink DA; Mulder M; van Paassen MM; Mulder M

2011-02-01

264

A Method to Measure the Relationship Between Biodynamic Feedthrough and Neuromuscular Admittance.  

Science.gov (United States)

Biodynamic feedthrough (BDFT) refers to a phenomenon where accelerations cause involuntary limb motions, which can result in unintentional control inputs that can substantially degrade manual control. It is known that humans can adapt the dynamics of their limbs by adjusting their neuromuscular settings, and it is likely that these adaptations have a large influence on BDFT. The goal of this paper is to present a method that can provide evidence for this hypothesis. Limb dynamics can be described by admittance, which is the causal dynamic relation between a force input and a position output. This paper presents a method to simultaneously measure BDFT and admittance in a motion-based simulator. The method was validated in an experiment. Admittance was measured by applying a force disturbance signal to the control device; BDFT was measured by applying a motion disturbance signal to the motion simulator. To allow distinguishing between the operator's responses to each disturbance signal, the perturbation signals were separated in the frequency domain. To show the impact of neuromuscular adaptation, subjects were asked to perform three different control tasks, each requiring a different setting of the neuromuscular system (NMS). Results show a dependence of BDFT on neuromuscular admittance: A change in neuromuscular admittance results in a change in BDFT dynamics. This dependence is highly relevant when studying BDFT. The data obtained with the proposed measuring method provide insight in how exactly the settings of the NMS influence the level of BDFT. This information can be used to gain fundamental knowledge on BDFT and also, for example, in the development of a canceling controller. PMID:21349792

Venrooij, Joost; Abbink, David A; Mulder, Mark; van Paassen, Marinus M; Mulder, Max

2011-02-24

265

Neuromuscular effects of G93A-SOD1 expression in zebrafish  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Amyotrophic lateral sclerosis (ALS) is a fatal disorder involving the degeneration and loss of motor neurons. The mechanisms of motor neuron loss in ALS are unknown and there are no effective treatments. Defects in the distal axon and at the neuromuscular junction are early events in the disease course, and zebrafish provide a promising in vivo system to examine cellular mechanisms and treatments for these events in ALS pathogenesis. Results We demonstrate that transient genetic manipulation of zebrafish to express G93A-SOD1, a mutation associated with familial ALS, results in early defects in motor neuron outgrowth and axonal branching. This is consistent with previous reports on motor neuron axonal defects associated with familial ALS genes following knockdown or mutant protein overexpression. We also demonstrate that upregulation of growth factor signaling is capable of rescuing these early defects, validating the potential of the model for therapeutic discovery. We generated stable transgenic zebrafish lines expressing G93A-SOD1 to further characterize the consequences of G93A-SOD1 expression on neuromuscular pathology and disease progression. Behavioral monitoring reveals evidence of motor dysfunction and decreased activity in transgenic ALS zebrafish. Examination of neuromuscular and neuronal pathology throughout the disease course reveals a loss of neuromuscular junctions and alterations in motor neuron innervations patterns with disease progression. Finally, motor neuron cell loss is evident later in the disease. Conclusions This sequence of events reflects the stepwise mechanisms of degeneration in ALS, and provides a novel model for mechanistic discovery and therapeutic development for neuromuscular degeneration in ALS.

Sakowski Stacey A; Lunn J; Busta Angela S; Oh Sang; Zamora-Berridi Grettel; Palmer Madeline; Rosenberg Andrew A; Philip Stephen G; Dowling James J; Feldman Eva L

2012-01-01

266

Neuromuscular effects of G93A-SOD1 expression in zebrafish.  

UK PubMed Central (United Kingdom)

BACKGROUND: Amyotrophic lateral sclerosis (ALS) is a fatal disorder involving the degeneration and loss of motor neurons. The mechanisms of motor neuron loss in ALS are unknown and there are no effective treatments. Defects in the distal axon and at the neuromuscular junction are early events in the disease course, and zebrafish provide a promising in vivo system to examine cellular mechanisms and treatments for these events in ALS pathogenesis. RESULTS: We demonstrate that transient genetic manipulation of zebrafish to express G93A-SOD1, a mutation associated with familial ALS, results in early defects in motor neuron outgrowth and axonal branching. This is consistent with previous reports on motor neuron axonal defects associated with familial ALS genes following knockdown or mutant protein overexpression. We also demonstrate that upregulation of growth factor signaling is capable of rescuing these early defects, validating the potential of the model for therapeutic discovery. We generated stable transgenic zebrafish lines expressing G93A-SOD1 to further characterize the consequences of G93A-SOD1 expression on neuromuscular pathology and disease progression. Behavioral monitoring reveals evidence of motor dysfunction and decreased activity in transgenic ALS zebrafish. Examination of neuromuscular and neuronal pathology throughout the disease course reveals a loss of neuromuscular junctions and alterations in motor neuron innervations patterns with disease progression. Finally, motor neuron cell loss is evident later in the disease. CONCLUSIONS: This sequence of events reflects the stepwise mechanisms of degeneration in ALS, and provides a novel model for mechanistic discovery and therapeutic development for neuromuscular degeneration in ALS.

Sakowski SA; Lunn JS; Busta AS; Oh SS; Zamora-Berridi G; Palmer M; Rosenberg AA; Philip SG; Dowling JJ; Feldman EL

2012-01-01

267

Mitochondrial control mechanism on apoptosis and ionizing radiation  

International Nuclear Information System (INIS)

[en] Mitochondria play a major role in apoptosis triggered by many stimuli. The various death signals induce directly and indirectly (through Bcl-2 family proteins) the increase of mitochondrial membrane permeability, the release of cytochrome c and the activation of caspases. The mechanisms that lead to this permeability are not yet completely understood. Here, authors review briefly the mechanisms of mitochondrial control during apoptosis and the possible effects of ionizing radiation in their mechanisms

2003-01-01

268

Metabolic syndrome: aggression control mechanisms gone out of control.  

UK PubMed Central (United Kingdom)

An upcoming hypothesis about the evolutionary origins of metabolic syndrome is that of a 'soldier' to 'diplomat' transition in behaviour and the accompanying metabolic adaptations. Theoretical as well as empirical studies have shown that similar to the soldier and diplomat dichotomy, physically aggressive and non-aggressive strategists coexist in animal societies with negative frequency dependent selection. Although dominant individuals have a higher reproductive success obtained through means such as greater access to females, subordinate individuals have alternative means such as sneak-mating for gaining a substantial reproductive success. The alternative behavioural strategies are associated with different neurophysiologic and metabolic states. Subordinate individuals typically have low testosterone, high plasma cholesterol and glucocorticoids and elevated serotonin signalling whereas dominant ones are characterized by high testosterone, low brain serotonin and lower plasma cholesterol. Food and sex are the main natural causes of aggression. However, since aggression increases the risk of injury, aggression control is equally crucial. Therefore chronic satiety in the form of fat should induce aggression control. It is not surprising that the satiety hormone serotonin has a major role in aggression control. Further chronically elevated serotonin signalling in the hypothalamus induces peripheral insulin resistance. Meta-analysis shows that most of the anti-aggression signal molecules are pro-obesity and pro-insulin-resistance. Physical aggression is known to increase secretion of epidermal growth factor (EGF) in anticipation of injuries and EGF is important in pancreatic beta cell regeneration too. In anticipation of injuries aggression related hormones also facilitate angiogenesis and angiogenesis dysfunction is the root cause of a number of co-morbidities of insulin resistance syndrome. Reduced injury proneness typical of 'diplomat' life style would also reorient the immune system resulting into delayed wound healing on the one hand and increased systemic inflammation on the other. Diabetes is negatively associated with physically aggressive behaviour. We hypothesize that suppression of physical aggression is the major behavioural cue for the development of metabolic syndrome. Preliminary trials of behavioural intervention indicate that games and exercises involving physical aggression reduce systemic inflammation and improve glycemic control.

Belsare PV; Watve MG; Ghaskadbi SS; Bhat DS; Yajnik CS; Jog M

2010-03-01

269

Quantitative quality control for mechanical isocenter in teletherapy  

International Nuclear Information System (INIS)

Teletherapy devices have a non point mechanical isocenter which can influence the quality of care and therefore, quality control protocols were established to evaluate this parameter. This work aims to create a method for measuring the mechanical isocenter to be made an assessment and validation of equipment. It used a mechanical ensemble, where the main component is a gauge, for measuring the size of a precision piece. The difference between the known and measured value is attributed to mechanical instability of the device in question. (author)

2009-01-01

270

Monolithic Controlled Delivery Systems: Part I. Basic Characteristics and Mechanisms  

Directory of Open Access Journals (Sweden)

Full Text Available The article considers contemporary systems for controlled delivery of active agents, such as drugs, agricultural chemicals, pollutants and additives in the environment. A useful classification of the available controlled release systems (CRS) is proposed according to the type of control (passive, active or self-preprogrammed) and according to the main controlling mechanism (diffusion, swelling, dissolution or erosion). Special attention is given to some of the most used CRS - polymer monoliths. The structural and physical-chemical characteristics of CRS as well as the basic approaches to their production are examined. The basic mechanisms of controlled agent release are reviewed in detail and factors influencing the release kinetics are classified according to their importance. The present study can be helpful for understanding and applying the available mathematical models and for developing more comprehensive ones intended for design of new controlled delivery systems.

Rumiana Blagoeva; Assen Nedev

2006-01-01

271

Research on Internal Flow Control Mechanism of For CES Routers  

Directory of Open Access Journals (Sweden)

Full Text Available To improve the communication efficiency and security between Control Elements (CEs) and Forwarding Elements (FEs) of For CES routers, this study researches on internal flow control mechanism. Firstly, an evaluation model based on communication of Transport Mapping Layer (TML) is proposed, which is used to improve service performance of TML. Secondly, in order to prevent redirect channel interference with control channel, this study proposes a bandwidth allocation algorithm called Dynamic Probabilistic Priority Based on Rate and Buffer (DPPBRB). Lastly, to avoid the potential congestion on control channel between one CE and multiple FEs, this study puts forward an internal flow control mechanism. These internal flow control methods that this study proposed effectively prevents the DoS attack from redirect messages and improves reliability of For CES routers. Simulation and experiment results show the feasibility and effectiveness of these methods.

Bin Zhuge; Cheng Yu; Kang-ping Liu; Wei-ming Wang

2011-01-01

272

Safety margin at single neuromuscular junctions.  

Science.gov (United States)

Jitter measurement with axonal microstimulation was used to study synaptic function at 115 neuromuscular junctions (NMJs) of normal subjects at various stimulation rates. Jitter was lowest at 0.5 Hz; it increased slightly at 1, 2, and 5 Hz and remained at that level at 10 Hz (a light work load) and 20 Hz (a heavy work load); and it increased further at 50 Hz (an extreme load). This pattern was seen for the majority of the NMJs, suggesting a high safety factor of neuromuscular transmission maintained rather uniformly over a wide range of discharge rates. A proportion of the normal NMJs had relatively large jitter; these tended to show prominent facilitation as the rate was raised from 5 or 10 to 20 Hz. Similar but more dramatic facilitation improving the safety factor was seen at most NMJs in myasthenia, which was studied for comparison. Such facilitation was not found at normal NMJs with low jitter. PMID:12116282

Trontelj, Joze V; Mihelin, Marjan; Khuraibet, Adnan

2002-01-01

273

Safety margin at single neuromuscular junctions.  

UK PubMed Central (United Kingdom)

Jitter measurement with axonal microstimulation was used to study synaptic function at 115 neuromuscular junctions (NMJs) of normal subjects at various stimulation rates. Jitter was lowest at 0.5 Hz; it increased slightly at 1, 2, and 5 Hz and remained at that level at 10 Hz (a light work load) and 20 Hz (a heavy work load); and it increased further at 50 Hz (an extreme load). This pattern was seen for the majority of the NMJs, suggesting a high safety factor of neuromuscular transmission maintained rather uniformly over a wide range of discharge rates. A proportion of the normal NMJs had relatively large jitter; these tended to show prominent facilitation as the rate was raised from 5 or 10 to 20 Hz. Similar but more dramatic facilitation improving the safety factor was seen at most NMJs in myasthenia, which was studied for comparison. Such facilitation was not found at normal NMJs with low jitter.

Trontelj JV; Mihelin M; Khuraibet A

2002-01-01

274

Neuromuscular electrical stimulation for skeletal muscle function.  

UK PubMed Central (United Kingdom)

Lack of neural innervation due to neurological damage renders muscle unable to produce force. Use of electrical stimulation is a medium in which investigators have tried to find a way to restore movement and the ability to perform activities of daily living. Different methods of applying electrical current to modify neuromuscular activity are electrical stimulation (ES), neuromuscular electrical stimulation (NMES), transcutaneous electrical nerve stimulation (TENS), and functional electrical stimulation (FES). This review covers the aspects of electrical stimulation used for rehabilitation and functional purposes. Discussed are the various parameters of electrical stimulation, including frequency, pulse width/duration, duty cycle, intensity/amplitude, ramp time, pulse pattern, program duration, program frequency, and muscle group activated, and how they affect fatigue in the stimulated muscle.

Doucet BM; Lam A; Griffin L

2012-06-01

275

Multiply Sectioned Bayesian Networks For Neuromuscular Diagnosis  

UK PubMed Central (United Kingdom)

A prototype neuromuscular diagnostic system (PAINULIM) that diagnoses painful or impaired upperlimbs has been developed based on Bayesian networks. This paper presents nonmathematically themajor knowledge representation issues that arose in the development of PAINULIM. Motivated by thecomputational overhead of large application domains, and the desire to provide a user with an interfacethat gives a focused display of a subdomain of current interest, we built PAINULIM using the idea ofmultiply sectioned Bayesian networks. A preliminary evaluation of PAINULIM with 76 patients hasdemonstrated good clinical performance.Keywords: Neuromuscular diagnosis, Probabilistic Reasoning, Bayesian Network, DecompositionCorrespondence to: Yang Xiang, Department of Computer Science, University of Regina, Regina,Sask., S4S 0A2 Canada, tel: 306 585 5226, email: yxiang@cs.uregina.ca1 IntroductionThis paper presents results of our research in developing the PAINULIM expert system for neuromus...

Y. Xiang; A. Eisen; M. P. Beddoes; D. Poole

276

Multiply Sectioned Bayesian Networks For Neuromuscular Diagnosis  

UK PubMed Central (United Kingdom)

A prototype neuromuscular diagnostic system (PAINULIM) that diagnoses painful or impaired upperlimbs has been developed based on Bayesian networks. This paper presents nonmathematically themajor knowledge representation issues that arose in the development of PAINULIM. Motivated by thecomputational overhead of large application domains, and the desire to provide a user with an interfacethat gives a focused display of a subdomain of current interest, we built PAINULIM using the idea ofmultiply sectioned Bayesian networks. A preliminary evaluation of PAINULIM with 76 patients hasdemonstrated good clinical performance.Keywords: Neuromuscular diagnosis, Probabilistic Reasoning, Bayesian Network, DecompositionCorrespondence to: Yang Xiang, Department of Computer Science, University of Regina, Regina,Sask., S4S 0A2 Canada, tel: 306 585 5226, email: yxiang@cs.uregina.ca11

Y. Xiang; A. Eisen; M. P. Beddoes; D. Poole

277

A case of congenital neuromuscular disease with uniform type I fibers, abnormal mitochondrial network and jagged Z-line.  

UK PubMed Central (United Kingdom)

Histological, histochemical and ultrastructural studies of muscle biopsy in a case of congenital neuromuscular disease revealed unusual findings consisting of muscle fibers uniformity which were all type I and of small diameter, jagged Z-line and abnormally developed transverse network of mitochondria. E.M.G. examination demonstrated a myopathic pattern, but mitochondrial changes are quite different from those reported in mitochondrial myopathies and jagged Z-line seems poorly correlated with Z-line streaming present in denervation atrophy, target fibers, core-like lesions or other Z-line abnormalities of the nemaline myopathy. On the other hand type I histochemical uniformity seems more likely related to some dysfunction of the neuronal mechanisms that control both the fiber type differentiation and other trophic influences. It also suggests that myogenic E.M.G. pattern might actually be pseudo-myopathic and due to a reduction of the cross sectional area of the individual muscle fibers composing the motor unit.

Pellegrini G; Barbieri S; Moggio M; Cheldi A; Scarlato G; Minetti C

1985-08-01

278

[Neuromuscular deficits in chronic ankle instability : Frequency and significance - multicenter study.  

Science.gov (United States)

The peroneal reaction time (PRT) is used in the assessment of neuromuscular deficits in chronic functional ankle instability. Powered by the Editorial Manager® and Preprint Manager® from Aries Systems Corporation the present study was conducted to determine the PRT in a large collective of patients with chronic ankle instability because it is unclear if this parameter of neuromuscular deficit is prolonged. In this study 186 patients underwent a diagnostic algorithm consisting of anamnesis, clinical examination, X-ray and determination of the PRT on a tilting platform. A prolonged PRT as a manifestation of a neuromuscular deficit could be detected in the majority of the patients (n?=?143, 77?%). Comparing the affected and healthy legs 77 patients (41?%) showed a significant difference in talar shift (p?=?0.002) and talar tilt (p?=?0.04) in the radiological stress views. Of these 77 patients only 15 (8?%) showed radiological evidence of a mechanical problem. As a consequence of recurring ankle sprains a post-traumatic deficit in proprioception has to be expected in most cases. In general a conservative therapy approach should be followed including specific training to improve neuromuscular and proprioceptive deficits. PMID:23652929

Schmidt, R; Becker, H P; Rauhut, F; Tannheimer, M

2013-05-01

279

[Neuromuscular deficits in chronic ankle instability : Frequency and significance - multicenter study.  

UK PubMed Central (United Kingdom)

The peroneal reaction time (PRT) is used in the assessment of neuromuscular deficits in chronic functional ankle instability. Powered by the Editorial Manager® and Preprint Manager® from Aries Systems Corporation the present study was conducted to determine the PRT in a large collective of patients with chronic ankle instability because it is unclear if this parameter of neuromuscular deficit is prolonged. In this study 186 patients underwent a diagnostic algorithm consisting of anamnesis, clinical examination, X-ray and determination of the PRT on a tilting platform. A prolonged PRT as a manifestation of a neuromuscular deficit could be detected in the majority of the patients (n?=?143, 77?%). Comparing the affected and healthy legs 77 patients (41?%) showed a significant difference in talar shift (p?=?0.002) and talar tilt (p?=?0.04) in the radiological stress views. Of these 77 patients only 15 (8?%) showed radiological evidence of a mechanical problem. As a consequence of recurring ankle sprains a post-traumatic deficit in proprioception has to be expected in most cases. In general a conservative therapy approach should be followed including specific training to improve neuromuscular and proprioceptive deficits.

Schmidt R; Becker HP; Rauhut F; Tannheimer M

2013-05-01

280

Effects of neuromuscular blocking agents on central respiratory chemosensitivity in newborn rats  

Scientific Electronic Library Online (English)

Full Text Available Abstract in english Neuromuscular blocking agents suppress central respiratory activity through their inhibitory effects on preinspiratory neurons and the synaptic drive from preinspiratory neurons to inspiratory neurons. Central CO2-chemosensitive areas, which partly consist of CO2-excited neurons, in the rostral ventrolateral medulla are thought to provide tonic drive to the central respiratory network and involve cholinergic mechanisms, which led us to hypothesize that neuromuscular block (more) ing agents can inhibit CO2-excited neurons and attenuate respiratory CO2 responsiveness. To test this hypothesis, we used isolated brainstem-spinal cord preparations from newborn rats. The increase of C4 burst frequency induced by a hypercapnic superfusate, i.e. respiratory CO2 responsiveness, was suppressed by the application of neuromuscular blocking agents, either d-tubocurarine (10, 100?M) or vecuronium (100?M). These agents (40?M) also induced hyperpolarization and decreases in firing frequency of CO2-excited neurons in the rostral ventrolateral medulla. Our results demonstrate that neuromuscular blocking agents inhibit CO2-excited tonic firing neurons and attenuate respiratory CO2 responsiveness.

SAKURABA, SHIGEKI; KUWANA, SHUN-ICHI; ERIKSSON, LARS I; OKADA, YASUMASA; OCHIAI, RYOICHI; KASHIWAGI, MASANORI; HATORI, EIKI; LINDAHL, STEN G. E.; TAKEDA, JUNZO

2005-01-01

 
 
 
 
281

Effects of neuromuscular blocking agents on central respiratory chemosensitivity in newborn rats  

Directory of Open Access Journals (Sweden)

Full Text Available Neuromuscular blocking agents suppress central respiratory activity through their inhibitory effects on preinspiratory neurons and the synaptic drive from preinspiratory neurons to inspiratory neurons. Central CO2-chemosensitive areas, which partly consist of CO2-excited neurons, in the rostral ventrolateral medulla are thought to provide tonic drive to the central respiratory network and involve cholinergic mechanisms, which led us to hypothesize that neuromuscular blocking agents can inhibit CO2-excited neurons and attenuate respiratory CO2 responsiveness. To test this hypothesis, we used isolated brainstem-spinal cord preparations from newborn rats. The increase of C4 burst frequency induced by a hypercapnic superfusate, i.e. respiratory CO2 responsiveness, was suppressed by the application of neuromuscular blocking agents, either d-tubocurarine (10, 100?M) or vecuronium (100?M). These agents (40?M) also induced hyperpolarization and decreases in firing frequency of CO2-excited neurons in the rostral ventrolateral medulla. Our results demonstrate that neuromuscular blocking agents inhibit CO2-excited tonic firing neurons and attenuate respiratory CO2 responsiveness.

SHIGEKI SAKURABA; SHUN-ICHI KUWANA; LARS I ERIKSSON; YASUMASA OKADA; RYOICHI OCHIAI; MASANORI KASHIWAGI; EIKI HATORI; STEN G. E. LINDAHL; JUNZO TAKEDA

2005-01-01

282

Neuromuscular scoliosis - surgical management and outcomes  

Scientific Electronic Library Online (English)

Full Text Available Abstract in english Neuromuscular scoliosis affects a heterogeneous group of patients with myopathic, upper and lower motor neuron diseases. Spinal surgery is often required to optimise respiratory, sitting and ambulatory function. OBJECTIVES: Review of management and outcomes of surgically treated neuromuscular scoliosis. STUDY DESIGN: Retrospective review of prospectively maintained data, including demographics, intra-operative variables, pre- and post-operative imaging, complications, out (more) comes and a telephonic follow-up questionnaire. RESULTS: Ninety-eight patients (45 male and 53 female) were included in the study. The average operating time was 230 (100-525 ± 60.9) minutes and an average of 15.4 (8-19 ± 2.9) levels were fused. Pedicle screw only constructs corrected the primary curve by 63% initially and 56% correction at last follow-up. Hybrid constructs had an immediate correction of 69% and 47% at last follow-up. Although pedicle screw constructs lost less correction when compared to hybrid constructs, this was not a statistically significant difference. Pelvic obliquity was corrected from 14.02 (0-80 ± 15.54) to 4.06 (0-35 ± 7.69) degrees. The majority of the telephonic responses were positive. CONCLUSION: : Corrective spinal surgery in the neuromuscular patient is demanding with a high rate of complications but outcomes are good, with radiographic correction maintained in the long term and high level of patient and parent satisfaction. LEVEL OF EVIDENCE: III

Puddu, A; Dunn, RN

2013-01-01

283

Synthesis of dissipative output feedback controllers. Application to mechanical systems  

Energy Technology Data Exchange (ETDEWEB)

This thesis presents new results on the synthesis of linear controllers with passivity, or more general, dissipativity properties. These methods may be applied to obtain more accurate control over mechanical systems and in the control of chemical processes that involve dissipative subsystems. The thesis presents two different approaches for synthesis of dissipative controllers: (1) A method that exploits the Riccati equation solution to the state space formulation of the H{sub {infinity}} control problem is investigated, illustrated by synthesising a controller for damping of flexible modes in a beam. (2) A more general method for dissipative control synthesis is developed that retains the well-known techniques of loop-shaping and frequency weighting in H{sub {infinity}}. A method is also presented for controller synthesis directly from frequency response data. 82 refs., 34 figs., 3 tabs.

Johannessen, Erling Aarsand

1997-12-31

284

Guidelines for treatment of autoimmune neuromuscular transmission disorders.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Important progress has been made in our understanding of the autoimmune neuromuscular transmission (NMT) disorders; myasthenia gravis (MG), Lambert-Eaton myasthenic syndrome (LEMS) and neuromyotonia (Isaacs' syndrome).

Skeie, GO; Apostolski, S; Evoli, A; Gilhus, NE; Illa, I; Harms, L

285

Whole-body vibration does not influence knee joint neuromuscular function or proprioception.  

UK PubMed Central (United Kingdom)

This study examined the acute effects of whole-body vibration (WBV) on knee joint position sense and indices of neuromuscular function, specifically strength, electromechanical delay and the rate of force development. Electromyography and electrically evoked contractions were used to investigate neural and contractile responses to WBV. Fourteen healthy males completed two treatment conditions on separate occasions: (1) 5 × 1 min of unilateral isometric squat exercise on a synchronous vibrating platform [30 Hz, 4 mm peak-to-peak amplitude] (WBV) and (2) a control condition (CON) of the same exercise without WBV. Knee joint position sense (joint angle replication task) and quadriceps neuromuscular function were assessed pre-, immediately-post and 1 h post-exercise. During maximum voluntary knee extensions, the peak force (PF(V)), electromechanical delay (EMD(V)), rate of force development (RFD(V)) and EMG of the quadriceps were measured. Twitch contractions of the knee extensors were electrically evoked to assess EMD(E) and RFD(E). The results showed no influence of WBV on knee joint position, EMD(V), PF(V) and RFD(V) during the initial 50, 100 or 150 ms of contraction. Similarly, electrically evoked neuromuscular function and neural activation remained unchanged following the vibration exercise. A single session of unilateral WBV did not influence any indices of thigh muscle neuromuscular performance or knee joint proprioception.

Hannah R; Minshull C; Folland JP

2013-02-01

286

Molecular Mechanisms Controlling the Cell Cycle in Embryonic Stem Cells.  

UK PubMed Central (United Kingdom)

Embryonic stem (ES) cells are originated from the inner cell mass of a blastocyst stage embryo. They can proliferate indefinitely, maintain an undifferentiated state (self-renewal), and differentiate into any cell type (pluripotency). ES cells have an unusual cell cycle structure, consists mainly of S phase cells, a short G1 phase and absence of G1/S checkpoint. Cell division and cell cycle progression are controlled by mechanisms ensuring the accurate transmission of genetic information from generation to generation. Therefore, control of cell cycle is a complicated process, involving several signaling pathways. Although great progress has been made on the molecular mechanisms involved in the regulation of ES cell cycle, many regulatory mechanisms remain unknown. This review summarizes the current knowledge about the molecular mechanisms regulating the cell cycle of ES cells and describes the relationship existing between cell cycle progression and the self-renewal.

Abdelalim EM

2013-08-01

287

Regulatory mechanisms controlling antibiotic production in Streptomyces clavuligerus.  

Science.gov (United States)

Streptomyces clavuligerus produces a large array of natural compounds with antibiotic, antitumor, beta-lactamase inhibition or inmunomodulating activities. The production of cephamycin C, clavulanic acid and other compounds with a clavam structure has been studied for many years. A network of regulatory mechanisms is present in S. clavuligerus to control the formation of different compounds by pathway-specific regulators or pleiotropic regulators. The possible existence of a gamma-butyrolactone signaling system in this streptomycete is emerging. In addition, S. clavuligerus possesses a stringent control mechanism somehow different from those previously reported in other Streptomyces species. PMID:18446393

Liras, Paloma; Gomez-Escribano, Juan P; Santamarta, Irene

2008-04-30

288

A feedback inclusive neuromuscular training program alters frontal plane kinematics.  

UK PubMed Central (United Kingdom)

Anterior cruciate ligament (ACL) neuromuscular training programs have demonstrated beneficial effects in reducing ACL injuries, yet further evaluation of their effects on biomechanical measures across a sports team season is required to elucidate the specific factors that are modifiable. The purpose of this study was to evaluate the effects of a 10-week off-season neuromuscular training program on lower extremity kinematics. Twelve Division I female soccer players (age: 19.2 ± 0.8 years, height: 1.67 ± 0.1 m, weight: 60.2 ± 6.5 kg) performed unanticipated dynamic trials of a running stop-jump task pretraining and posttraining. Data collection was performed using an 8-camera Vicon system (Los Angeles, CA, USA) and 2 Bertec (Columbus, OH, USA) force plates. The 10-week training program consisted of resistance training 2 times per week and field training, consisting of plyometric, agility, and speed drills, 2 times per week. Repeated measures analyses of variance (ANOVAs) were used to assess the differences between pretraining and posttraining kinetics and kinematics of the hip, knee, and ankle at initial contact (IC), peak knee flexion (PKF), and peak stance. Repeated measures ANOVAs were also used to assess isometric strength differences pretraining and posttraining. The alpha level was set at 0.05 a priori. The training program demonstrated significant increases in left hip extension, left and right hip flexion, and right hip adduction isometric strength. At IC, knee abduction angle moved from an abducted to an adducted position (-1.48 ± 3.65° to 1.46 ± 3.86°, p = 0.007), and hip abduction angle increased (-6.05 ± 4.63° to -10.34 ± 6.83°, p = 0.007). Hip abduction angle at PKF increased (-2.23 ± 3.40° to 6.01 ± 3.82°, p = 0.002). The maximum knee extension moment achieved at peak stance increased from pretraining to posttraining (2.02 ± 0.32 to 2.38 ± 0.75 N·m·kg?¹, p = 0.027). The neuromuscular training program demonstrated a potential positive effect in altering mechanics that influence the risk of incurring an ACL injury.

Greska EK; Cortes N; Van Lunen BL; Oñate JA

2012-06-01

289

Neuromuscular blockers in early acute respiratory distress syndrome.  

UK PubMed Central (United Kingdom)

BACKGROUND: In patients undergoing mechanical ventilation for the acute respiratory distress syndrome (ARDS), neuromuscular blocking agents may improve oxygenation and decrease ventilator-induced lung injury but may also cause muscle weakness. We evaluated clinical outcomes after 2 days of therapy with neuromuscular blocking agents in patients with early, severe ARDS. METHODS: In this multicenter, double-blind trial, 340 patients presenting to the intensive care unit (ICU) with an onset of severe ARDS within the previous 48 hours were randomly assigned to receive, for 48 hours, either cisatracurium besylate (178 patients) or placebo (162 patients). Severe ARDS was defined as a ratio of the partial pressure of arterial oxygen (PaO2) to the fraction of inspired oxygen (FIO2) of less than 150, with a positive end-expiratory pressure of 5 cm or more of water and a tidal volume of 6 to 8 ml per kilogram of predicted body weight. The primary outcome was the proportion of patients who died either before hospital discharge or within 90 days after study enrollment (i.e., the 90-day in-hospital mortality rate), adjusted for predefined covariates and baseline differences between groups with the use of a Cox model. RESULTS: The hazard ratio for death at 90 days in the cisatracurium group, as compared with the placebo group, was 0.68 (95% confidence interval [CI], 0.48 to 0.98; P=0.04), after adjustment for both the baseline PaO2:FIO2 and plateau pressure and the Simplified Acute Physiology II score. The crude 90-day mortality was 31.6% (95% CI, 25.2 to 38.8) in the cisatracurium group and 40.7% (95% CI, 33.5 to 48.4) in the placebo group (P=0.08). Mortality at 28 days was 23.7% (95% CI, 18.1 to 30.5) with cisatracurium and 33.3% (95% CI, 26.5 to 40.9) with placebo (P=0.05). The rate of ICU-acquired paresis did not differ significantly between the two groups. CONCLUSIONS: In patients with severe ARDS, early administration of a neuromuscular blocking agent improved the adjusted 90-day survival and increased the time off the ventilator without increasing muscle weakness. (Funded by Assistance Publique-Hôpitaux de Marseille and the Programme Hospitalier de Recherche Clinique Régional 2004-26 of the French Ministry of Health; ClinicalTrials.gov number, NCT00299650.)

Papazian L; Forel JM; Gacouin A; Penot-Ragon C; Perrin G; Loundou A; Jaber S; Arnal JM; Perez D; Seghboyan JM; Constantin JM; Courant P; Lefrant JY; Guérin C; Prat G; Morange S; Roch A

2010-09-01

290

Pole assignment for control of flexible link mechanisms  

Science.gov (United States)

Although the dynamics of flexible link mechanisms and manipulators is nonlinear, motion and vibration control often relies on linear or piecewise-linear controllers based on linearized models in order to ensure real-time implementability. Keeping such an objective in mind, this paper proposes a general receptance-based method for pole assignment in flexible link mechanisms with a single rigid-body degree of freedom (dof) using a single control force (i.e. rank-one control). A chief advantage of the approach proposed is that it makes use of the second-order system model representation through the receptance matrix of the symmetric part of the asymmetric model. The asymmetric terms in the stiffness and damping matrices arise from the coupling between rigid-body motion and elastic motion. The proposed receptance-based formulation ensures numerical reliability and efficiency also for large dimensional and ill-conditioned system models originating from the simultaneous presence of high-frequency and weakly controllable oscillating modes, and of rigid-body motion low-frequency dynamics, which may also be unstable. The validation of the proposed technique is carried out by performing pole assignment through position and velocity feedback or acceleration and velocity feedback on a mechanism. Integral control is also introduced to improve the steady state system response. Numerical results indicate that the proposed method is more accurate and robust than two popular established methods.

Ouyang, H.; Richiedei, D.; Trevisani, A.

2013-06-01

291

Neuromuscular disorders of glycogen metabolism.  

UK PubMed Central (United Kingdom)

Disorders of glycogen metabolism are inborn errors of energy homeostasis affecting primarily skeletal muscle, heart, liver, and, less frequently, the central nervous system. These rare diseases are quite variable in age of onset, symptoms, morbidity, and mortality. This review provides an update on disorders of glycogen metabolism affecting skeletal muscle exclusively or predominantly. From a pathogenetic perspective, we classify these diseases as primary, if the defective enzyme is directly involved in glycogen/glucose metabolism, or secondary, if the genetic mutation affects proteins which indirectly regulate glycogen or glucose processing. In addition to summarizing the most recent clinical reports in this field, we briefly describe animal models of human glycogen disorders. These experimental models are greatly improving the understanding of the pathogenetic mechanisms underlying the muscle degenerative process associated to these diseases and provide in vivo platforms to test new therapeutic strategies.

Gazzerro E; Andreu AL; Bruno C

2013-03-01

292

Avaliação da ativação neuromuscular em indivíduos com escoliose através da eletromiografia de superfície Assessment of neuromuscular activation in individuals with scoliosis using surface electromyography  

Directory of Open Access Journals (Sweden)

Full Text Available OBJETIVO: O objetivo desse estudo foi verificar o potencial da eletromiografia (EMG) de superfície para a avaliação da eficiência neuromuscular e da fadiga muscular localizada dos extensores lombares em indivíduos com escoliose. MÉTODOS: Participaram deste estudo 20 indivíduos divididos igualmente em dois grupos, (1) Grupo com Escoliose e (2) Grupo Controle, que foram submetidos a um teste de indução dos músculos extensores lombares a fadiga, o qual constituiu da realização de uma contração voluntária máxima isométrica (CVM), e realização de um teste com esforço a 80% da CVM. Foram coletados simultaneamente sinais de força e eletromiográficos (sinal EMG). O sinal EMG foi processado no domínio da freqüência, utilizando-se a transformada rápida de Fourier (FFT), por meio da mediana da freqüência (MF), e no domínio do tempo, pelo cálculo do valor root mean square (RMS). Os dados foram submetidos a uma análise de variância one-way para verificar as diferenças entre os dois grupos. Para verificar a simetria entre os lados direito e esquerdo, foi realizado o teste t pareado. O nível de significância adotado foi 0,05. RESULTADOS: os resultados demonstraram que indivíduos com escoliose apresentaram: (1) simetria de ativação neuromuscular entre os lados; (2) menor eficiência neuromuscular; (3) maior capacidade de resistir a fadiga; e (4) valores de força 42,6% menores que os indivíduos do GC. CONCLUSÕES: Os resultados sugerem que a EMG de superfície corresponde a um efetivo instrumento de avaliação funcional da escoliose, embora o protocolo estabelecido tenha limitado a participação dos indivíduos com escoliose, do ponto de vista da eficiência neuromuscular.OBJECTIVE: The aim of this study was to investigate the potential of surface electromyography (EMG) for assessing neuromuscular efficiency and localized muscle fatigue in the lumbar extensors, in individuals with scoliosis. METHODS: Twenty individuals participated in this study, divided equally into two groups: (1) Scoliosis Group and (2) Control Group. These subjects underwent a fatigue induction test on their lumbar extensor muscles, consisting of one maximum voluntary isometric contraction (MVIC) followed by a test at 80% of the MVIC effort. Force and EMG signals were collected simultaneously. The EMG signal was processed in the frequency domain by means of fast Fourier transforms using the median frequency; and in the time domain by calculating the root mean square value. The data were analyzed by means of one-way analysis of variance to investigate the differences between the two groups. Paired t test was used to investigate the symmetry between the right and left sides. The significance level adopted was 0.05. RESULTS: The results showed that the individuals with scoliosis presented: (1) symmetrical neuromuscular activation between the sides; (2) lower neuromuscular efficiency; (3) greater capacity to resist fatigue; and (4) force values 42.6% lower than those of the individuals in the Control Group. CONCLUSIONS: The results suggest that surface EMG is an effective tool for functional assessments of scoliosis, although the protocol established limited the participation of individuals with scoliosis, from the perspective of neuromuscular efficiency.

E Bassani; CT Candotti; M Pasini; M Melo; M La Torre

2008-01-01

293

Avaliação da ativação neuromuscular em indivíduos com escoliose através da eletromiografia de superfície/ Assessment of neuromuscular activation in individuals with scoliosis using surface electromyography  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese OBJETIVO: O objetivo desse estudo foi verificar o potencial da eletromiografia (EMG) de superfície para a avaliação da eficiência neuromuscular e da fadiga muscular localizada dos extensores lombares em indivíduos com escoliose. MÉTODOS: Participaram deste estudo 20 indivíduos divididos igualmente em dois grupos, (1) Grupo com Escoliose e (2) Grupo Controle, que foram submetidos a um teste de indução dos músculos extensores lombares a fadiga, o qual constituiu d (more) a realização de uma contração voluntária máxima isométrica (CVM), e realização de um teste com esforço a 80% da CVM. Foram coletados simultaneamente sinais de força e eletromiográficos (sinal EMG). O sinal EMG foi processado no domínio da freqüência, utilizando-se a transformada rápida de Fourier (FFT), por meio da mediana da freqüência (MF), e no domínio do tempo, pelo cálculo do valor root mean square (RMS). Os dados foram submetidos a uma análise de variância one-way para verificar as diferenças entre os dois grupos. Para verificar a simetria entre os lados direito e esquerdo, foi realizado o teste t pareado. O nível de significância adotado foi 0,05. RESULTADOS: os resultados demonstraram que indivíduos com escoliose apresentaram: (1) simetria de ativação neuromuscular entre os lados; (2) menor eficiência neuromuscular; (3) maior capacidade de resistir a fadiga; e (4) valores de força 42,6% menores que os indivíduos do GC. CONCLUSÕES: Os resultados sugerem que a EMG de superfície corresponde a um efetivo instrumento de avaliação funcional da escoliose, embora o protocolo estabelecido tenha limitado a participação dos indivíduos com escoliose, do ponto de vista da eficiência neuromuscular. Abstract in english OBJECTIVE: The aim of this study was to investigate the potential of surface electromyography (EMG) for assessing neuromuscular efficiency and localized muscle fatigue in the lumbar extensors, in individuals with scoliosis. METHODS: Twenty individuals participated in this study, divided equally into two groups: (1) Scoliosis Group and (2) Control Group. These subjects underwent a fatigue induction test on their lumbar extensor muscles, consisting of one maximum voluntary (more) isometric contraction (MVIC) followed by a test at 80% of the MVIC effort. Force and EMG signals were collected simultaneously. The EMG signal was processed in the frequency domain by means of fast Fourier transforms using the median frequency; and in the time domain by calculating the root mean square value. The data were analyzed by means of one-way analysis of variance to investigate the differences between the two groups. Paired t test was used to investigate the symmetry between the right and left sides. The significance level adopted was 0.05. RESULTS: The results showed that the individuals with scoliosis presented: (1) symmetrical neuromuscular activation between the sides; (2) lower neuromuscular efficiency; (3) greater capacity to resist fatigue; and (4) force values 42.6% lower than those of the individuals in the Control Group. CONCLUSIONS: The results suggest that surface EMG is an effective tool for functional assessments of scoliosis, although the protocol established limited the participation of individuals with scoliosis, from the perspective of neuromuscular efficiency.

Bassani, E; Candotti, CT; Pasini, M; Melo, M; La Torre, M

2008-02-01

294

Quasivelocities and Optimal Control for underactuated Mechanical Systems  

International Nuclear Information System (INIS)

This paper is concerned with the application of the theory of quasivelocities for optimal control for underactuated mechanical systems. Using this theory, we convert the original problem in a variational second-order lagrangian system subjected to constraints. The equations of motion are geometrically derived using an adaptation of the classical Skinner and Rusk formalism.

2010-07-28

295

Fabrication and utilization of mechanically controllable break junction for bioelectronics  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In scope of this work, a mechanically controllable break junction (MCBJ) setup was established and used for the investigation of electron transport properties of molecules in four related aspects. The main feature of MCBJs, fabricated here, is their impressive stability. Spring steel substrates with...

Xiang, Dong

296

Bellows for Control Rod Drive Mechanism of MONJU.  

Science.gov (United States)

The full mock-up operation test of Control Rod Drive Mechanism (CRDM) for MONJU have been carried on since 1972 in OEC of PNC. Welded type bellows were adopted for CRDM as the boundary between sodium and atmosphere. In design, two different locations were...

S. Matsumoto T. Ogawa Y. Ishii Y. Yamagishi F. Suzuki

1979-01-01

297

Quasivelocities and Optimal Control for Underactuated Mechanical Systems  

CERN Document Server

This paper is concerned with the application of the theory of quasivelocities for optimal control for underactuated mechanical systems. Using this theory, we convert the original problem in a variational second-order lagrangian system subjected to constraints. The equations of motion are geometrically derived using an adaptation of the classical Skinner and Rusk formalism.

Colombo, L

2010-01-01

298

Context-Based E-Health System Access Control Mechanism  

Science.gov (United States)

E-Health systems logically demand a sufficiently fine-grained authorization policy for access control. The access to medical information should not be just role-based but should also include the contextual condition of the role to access data. In this paper, we present a mechanism to extend the standard role-based access control to incorporate contextual information for making access control decisions in e-health application. We present an architecture consisting of authorisation and context infrastructure that work cooperatively to grant access rights based on context-aware authorization policies and context information.

Al-Neyadi, Fahed; Abawajy, Jemal H.

299

Acute neuromuscular weakness associated with dengue infection.  

UK PubMed Central (United Kingdom)

BACKGROUND: Dengue infections may present with neurological complications. Whether these are due to neuromuscular disease or electrolyte imbalance is unclear. MATERIALS AND METHODS: Eighty-eight patients of dengue fever required hospitalization during epidemic in year 2010. Twelve of them presented with acute neuromuscular weakness. We enrolled them for study. Diagnosis of dengue infection based on clinical profile of patients, positive serum IgM ELISA, NS1 antigen, and sero-typing. Complete hemogram, kidney and liver functions, serum electrolytes, and creatine phosphokinase (CPK) were tested. In addition, two patients underwent nerve conduction velocity (NCV) test and electromyography. RESULTS: Twelve patients were included in the present study. Their age was between 18 and 34 years. Fever, myalgia, and motor weakness of limbs were most common presenting symptoms. Motor weakness developed on 2(nd) to 4(th) day of illness in 11 of 12 patients. In one patient, it developed on 10(th) day of illness. Ten of 12 showed hypokalemia. One was of Guillain-Barré syndrome and other suffered from myositis; they underwent NCV and electromyography. Serum CPK and SGOT raised in 8 out of 12 patients. CPK of patient of myositis was 5098 IU. All of 12 patients had thrombocytopenia. WBC was in normal range. Dengue virus was isolated in three patients, and it was of serotype 1. CSF was normal in all. Within 24 hours, those with hypokalemia recovered by potassium correction. CONCLUSIONS: It was concluded that the dengue virus infection led to acute neuromuscular weakness because of hypokalemia, myositis, and Guillain-Barré syndrome. It was suggested to look for presence of hypokalemia in such patients.

Hira HS; Kaur A; Shukla A

2012-01-01

300

Offaxis neuromuscular training of knee injuries using an offaxis robotic elliptical trainer.  

UK PubMed Central (United Kingdom)

The goal of this study was to use an offaxis robotic elliptical trainer to improve off-axis neuromuscular control in people with knee injuries. Thirteen individuals with knee injuries participated in the study. Among them, 8 individuals participated in 18 sessions of pivoting offaxis intensity-adjustable neuromuscular control training (POINT) (3 sessions/week for 6 weeks including 3 evaluation sessions) to improve offaxis neuromuscular control, specifically dynamic lower limb stability in pivoting. 5 individuals served as controls who only participated in the three evaluations. Following POINT patients in the training group reduced pivoting instability (p=0.024), while the control group did not (p=0.118). Individuals in the training group were able to hop farther in a single leg hop for distance task, take shorter in 12 m hop time for time task, and reported reduced knee pain. The results suggest that subject-specific POINT utilizing the novel robotic elliptical trainer can be implemented as a rehabilitation protocol for patients with knee injuries to improve their lower limb functions and reduce knee symptoms.

Lee SJ; Ren Y; Geiger F; Chang AH; Press JM; Zhang LQ

2011-01-01

 
 
 
 
301

Inter-animal variability in the effects of C-type allatostatin on the cardiac neuromuscular system in the lobster Homarus americanus.  

UK PubMed Central (United Kingdom)

Although the global effects of many modulators on pattern generators are relatively consistent among preparations, modulators can induce different alterations in different preparations. We examined the mechanisms that underlie such variability in the modulatory effects of the peptide C-type allatostatin (C-AST; pQIRYHQCYFNPISCF) on the cardiac neuromuscular system of the lobster Homarus americanus. Perfusion of C-AST through the semi-intact heart consistently decreased the frequency of ongoing contractions. However, the effect of C-AST on contraction amplitude varied between preparations, decreasing in some preparations and increasing in others. To investigate this variable effect, we examined the effects of C-AST both peripherally and centrally. When contractions of the myocardium were elicited by controlled stimuli, C-AST did not alter heart contraction at the periphery (myocardium or neuromuscular junction) in any hearts. However, when applied either to the semi-intact heart or to the cardiac ganglion (CG) isolated from hearts that responded to C-AST with increased contraction force, C-AST increased both motor neuron burst duration and the number of spikes per burst by about 25%. In contrast, CG output was increased only marginally in hearts that responded to C-AST with a decrease in contraction amplitude, suggesting that the decrease in amplitude in those preparations resulted from decreased peripheral facilitation. Our data suggest that the differential effects of a single peptide on the cardiac neuromuscular system are due solely to differential effects of the peptide on the pattern generator; the extent to which the peptide induces increased burst duration is crucial in determining its overall effect on the system.

Wiwatpanit T; Powers B; Dickinson PS

2012-07-01

302

Optimal piezo-electro-mechanical coupling to control plate vibrations  

CERN Multimedia

A new way of coupling electrical and mechanical waves, using piezoelectric effect, is presented here. Since the energy exchange between two systems supporting wave propagation is maximum when their evolution is governed by similar equations, hence, an optimal electromechanical coupling is obtained by designing an electric network which is "analog" to the mechanical structure to be controlled. In this paper, we exploit this idea to enhance the coupling, between a Kirchhoff-Love plate and one possible synthesis of its circuital analog, as obtained by means of a set of piezoelectric actuators uniformly distributed upon the plate. It is shown how this approach allows for an optimal energy exchange between the mechanic and the electric forms independent of the modal evolution of the structure. Moreover, we show how an efficient electric dissipation of the mechanical energy can be obtained adding dissipative elements in the electric network.

Alessandroni, S; Frezza, F

2010-01-01

303

Adaptive Control Mechanism for Cable Modem MAC Protocols  

UK PubMed Central (United Kingdom)

Cable plants were initially designed for one-way broadcastof analog television signals (from the head-end to theneighborhood). They are now being upgraded to provide anupstream path (from the home to the head-end). New challengesarise in using the upstream channel since the availablebandwidth is low and the noise levels are high. Different variationsof the reservation Aloha protocol have been proposedas the MAC protocol to efficiently share the scarce upstreamcapacity. The efficiency of the reservation protocol highlydepends on the capacity assigned to the reservation channel.In this paper we present a control mechanism that dynamicallyadjusts the operating parameters to the current loadon the system. The control mechanism does not require anyframing structure and is built around a "sea of mini-slots".The performance under both static and highly dynamic loadsis close to optimum. The station implementation remainsparticularly simple and the downstream control structure i...

Dolors Sala; John O. Limb; Sunil U. Khaunte

304

Effect of salbutamol on neuromuscular function in endurance athletes.  

UK PubMed Central (United Kingdom)

PURPOSE: The potential ergogenic effects of therapeutic inhaled salbutamol doses in endurance athletes have been controversially discussed for decades. We hypothesized that salbutamol inhalation may increase peripheral muscle contractility, reduce fatigability, and improve force recovery after a localized exercise in endurance athletes. METHODS: Eleven healthy, nonasthmatic male athletes with high aerobic capacities were recruited to be compared in a double-blinded, randomized crossover study of two dose levels of salbutamol (200 and 800 ?g) and a placebo administered by inhalation before a quadriceps fatigue test. Subjects performed an incremental exercise protocol consisting in sets of 10 intermittent isometric contractions starting at 20% of maximum voluntary contraction (MVC) with 10% MVC increment until exhaustion. Femoral nerve magnetic stimulation was used during and after MVC to evaluate neuromuscular fatigue after each set, at task failure, and after 10 and 30 min of recovery. RESULTS: Initial MVC and evoked muscular responses were not modified with salbutamol (P > 0.05). The total number of submaximal contractions until task failure significantly differed between treatments (placebo, 72 ± 7; 200 µg, 78 ± 8; and 800 µg, 82 ± 7; P < 0.01). MVC and evoked muscular responses were similarly reduced with all treatments during the fatiguing task (all P > 0.05). Voluntary activation was unaffected by the fatiguing task and treatments (P > 0.05). CONCLUSION: Supratherapeutic inhaled doses of ?2-agonists increased quadriceps endurance during an incremental and localized fatiguing task in healthy endurance-trained athletes without significant effect on neuromuscular fatigue. Further studies are needed to clarify the underlying mechanisms.

Decorte N; Bachasson D; Guinot M; Flore P; Levy P; Verges S; Wuyam B

2013-10-01

305

Topology of optimally controlled quantum mechanical transition probability landscapes  

International Nuclear Information System (INIS)

An optimally controlled quantum system possesses a search landscape defined by the physical objective as a functional of the control field. This paper particularly explores the topological structure of quantum mechanical transition probability landscapes. The quantum system is assumed to be controllable and the analysis is based on the Euler-Lagrange variational equations derived from a cost function only requiring extremizing the transition probability. It is shown that the latter variational equations are automatically satisfied as a mathematical identity for control fields that either produce transition probabilities of zero or unit value. Similarly, the variational equations are shown to be inconsistent (i.e., they have no solution) for any control field that produces a transition probability different from either of these two extreme values. An upper bound is shown to exist on the norm of the functional derivative of the transition probability with respect to the control field anywhere over the landscape. The trace of the Hessian, evaluated for a control field producing a transition probability of a unit value, is shown to be bounded from below. Furthermore, the Hessian at a transition probability of unit value is shown to have an extensive null space and only a finite number of negative eigenvalues. Collectively, these findings show that (a) the transition probability landscape extrema consists of values corresponding to no control or full control, (b) approaching full control involves climbing a gentle slope with no false traps in the control space and (c) an inherent degree of robustness exists around any full control solution. Although full controllability may not exist in some applications, the analysis provides a basis to understand the evident ease of finding controls that produce excellent yields in simulations and in the laboratory.

2006-01-01

306

Mechanisms in Environmentally-Assisted One-photon Phase Control  

CERN Multimedia

The ability of an environment to assist in one-photon phase control relies upon entanglement between the system and bath and on the breaking of the time reversal symmetry. Here, one photon phase control is examined analytically and numerically in a model system, allowing an analysis of the relative strength of these contributions. Further, the significant role of non-Markovian dynamics and of moderate system-bath coupling in enhancing one-photon phase control is demonstrated, and an explicit role for quantum mechanics is noted in the existence of initial non-zero stationary coherences. Finally, desirable conditions are shown to be required to observe such environmentally assisted control, since the system will naturally equilibrate with its environment at longer times, ultimately resulting in the loss of phase control.

Pachon, Leonardo A

2013-01-01

307

The response of cortical alpha activity to pain and neuromuscular changes caused by exercise-induced muscle damage.  

UK PubMed Central (United Kingdom)

Exercise-induced muscle damage (EIMD) is characterized by pain, swelling, and shortening of the muscle; increased serum creatine kinase; decreased force output; and altered neuromuscular function. The aim of this study was to investigate the effects of EIMD to determine the relationship between the peripheral symptoms, neuromuscular changes, and delayed pain sensation during a submaximal movement of the biceps brachii on cortical alpha (?) activity. In contrast to the control (n?=?12) group, the experimental (n?=?16) group participated in an EIMD protocol, and both groups were monitored for 132?h post-EIMD protocol. At 12?h, neuromuscular functioning was already disturbed while the sensation of pain was perceived, but not fully developed. Muscle pain scores in the experimental group peaked after 36?h with the lowest torque reported at 12?h. ?-1 activity increased significantly in the motor and somatosensory area 12?h post-EIMD while ?-2 activity increased in the contralateral fronto-central area. At 36?h, pain had further increased and neuromuscular function improved while ?-1 and ?-2 activities had decreased. We hypothesize that ?-1 activity over the motor and somatosensory cortex of the experimental group displays a compensatory increase in response to the changes in neuromuscular function during movement, while an increase in ?-2 activity is related to the suppression of pain experienced within the first 12?h.

Plattner K; Lambert MI; Tam N; Baumeister J

2012-06-01

308

Isokinetic testing in patients with neuromuscular diseases: a focused review.  

UK PubMed Central (United Kingdom)

OBJECTIVE: This literature review aimed to study the use of isokinetic testing in patients with neuromuscular diseases (NMDs) and to identify directions for future research of isokinetic testing. DESIGN: The MEDLINE (January 1, 1965, to July 1, 2010), Cumulative Index to Nursing and Allied Health (1980 to May 2010), and Cochrane Central Register of Controlled Trials (The Cochrane Library Issue 3, 2009) electronic databases were searched. The literature search was conducted using the keywords muscle assessment, muscle strength, evaluation, isokinetic, neuromuscular diseases, muscle fatigue, functional test, rehabilitation, and literature search. Relevant references cited in the selected articles were also considered, regardless of the year of publication. RESULTS: The search strategy yielded 13 articles involving a variety of patients with known NMDs. All studies demonstrated that isokinetic dynamometry is appropriate and safe for ambulatory patients with NMDs. Isokinetic testing has proven to be reliable (intratest/intertest correlation coefficient ranged from 0.65 to 0.98), with the proximal muscles having the highest reliability, and sensitive to disease progression and to the effects of various therapeutic interventions. However, isokinetic testing has never gained wide acceptance, partly because of concerns about stabilizing the dynamometer and the subject during the test and of the lack of standardized protocols for isokinetic strength measurement. CONCLUSIONS: Isokinetic testing is an important part of the comprehensive evaluation and rehabilitation of patients with NMD. Research has demonstrated its efficacy in providing clinically relevant information. When integrated with a complete history, physical examination, and functional evaluation, isokinetic testing and exercise can be a valuable tool for the clinician in the assessment, rehabilitation, and performance enhancement of patients with NMD. Such equipment, however, has several disadvantages, rendering it usually impractical in the clinical setting.

El Mhandi L; Bethoux F

2013-02-01

309

Combined application of neuromuscular electrical stimulation and voluntary muscular contractions.  

Science.gov (United States)

Electromyostimulation (EMS) and voluntary muscle contraction (VC) constitute different modes of muscle activation and induce different acute physiological effects on the neuromuscular system. Long-term application of each mode of muscle activation can produce different muscle adaptations. It seems theoretically possible to completely or partially cumulate the muscle adaptations induced by each mode of muscle activation applied separately. This work consisted of examining the literature concerning the muscle adaptations induced by long-term application of the combined technique (CT) [i.e. EMS is combined with VC - non-simultaneously] compared with VC and/or EMS alone in healthy subjects and/or athletes and in post-operative knee-injured subjects. In general, CT induced greater muscular adaptations than VC whether in sports training or rehabilitation. This efficiency would be due to the fact that CT can facilitate cumulative effects of training completely or partially induced by VC and EMS practiced alone. CT also provides a greater improvement of the performance of complex dynamic movements than VC. However, EMS cannot improve coordination between different agonistic and antagonistic muscles and thus does not facilitate learning the specific coordination of complex movements. Hence, EMS should be combined with specific sport training to generate neuromuscular adaptations, but also allow the adjustment of motor control during a voluntary movement. Likewise, in a therapeutic context, CT was particularly efficient to accelerate recovery of muscle contractility during a rehabilitation programme. Strength loss and atrophy inherent in a traumatism and/or a surgical operation would be more efficiently compensated with CT than with VC. Furthermore, CT also restored more functional abilities than VC. Finally, in a rehabilitation context, EMS is complementary to voluntary exercise because in the early phase of rehabilitation it elicits a strength increase, which is necessary to perform voluntary training during the later rehabilitation sessions. PMID:18201117

Paillard, Thierry

2008-01-01

310

Combined application of neuromuscular electrical stimulation and voluntary muscular contractions.  

UK PubMed Central (United Kingdom)

Electromyostimulation (EMS) and voluntary muscle contraction (VC) constitute different modes of muscle activation and induce different acute physiological effects on the neuromuscular system. Long-term application of each mode of muscle activation can produce different muscle adaptations. It seems theoretically possible to completely or partially cumulate the muscle adaptations induced by each mode of muscle activation applied separately. This work consisted of examining the literature concerning the muscle adaptations induced by long-term application of the combined technique (CT) [i.e. EMS is combined with VC - non-simultaneously] compared with VC and/or EMS alone in healthy subjects and/or athletes and in post-operative knee-injured subjects. In general, CT induced greater muscular adaptations than VC whether in sports training or rehabilitation. This efficiency would be due to the fact that CT can facilitate cumulative effects of training completely or partially induced by VC and EMS practiced alone. CT also provides a greater improvement of the performance of complex dynamic movements than VC. However, EMS cannot improve coordination between different agonistic and antagonistic muscles and thus does not facilitate learning the specific coordination of complex movements. Hence, EMS should be combined with specific sport training to generate neuromuscular adaptations, but also allow the adjustment of motor control during a voluntary movement. Likewise, in a therapeutic context, CT was particularly efficient to accelerate recovery of muscle contractility during a rehabilitation programme. Strength loss and atrophy inherent in a traumatism and/or a surgical operation would be more efficiently compensated with CT than with VC. Furthermore, CT also restored more functional abilities than VC. Finally, in a rehabilitation context, EMS is complementary to voluntary exercise because in the early phase of rehabilitation it elicits a strength increase, which is necessary to perform voluntary training during the later rehabilitation sessions.

Paillard T

2008-01-01

311

Electrophysiological study in neuromuscular junction disorders.  

Science.gov (United States)

This review is on ultrastructure and subcellular physiology at normal and abnormal neuromuscular junctions. The clinical and electrophysiological findings in myasthenia gravis, Lambert-Eaton myasthenic syndrome (LEMS), congenital myasthenic syndromes, and botulinum intoxication are discussed. Single fiber electromyography (SFEMG) helps to explain the basis of testing neuromuscular junction function by repetitive nerve stimulation (RNS). SFEMG requires skill and patience and its availability is limited to a few centers. For RNS supramaximal stimulation is essential and so is display of the whole waveform of each muscle response at maximum amplitude. The amplitudes of the negative phase of the first and fourth responses are measured from baseline to negative peak, and the percent change of the fourth response compared with the first represents the decrement or increment. A decrement greater than 10% is accepted as abnormal and smooth progression of response amplitude train and reproducibility form the crux. In suspected LEMS the effect of fast rates of stimulation should be determined after RNS response to slow rates of stimulation. Caution is required to avoid misinterpretation of potentiation and pseudofacilitation. PMID:23661960

Cherian, Ajith; Baheti, Neeraj N; Iype, Thomas

2013-01-01

312

Neuromuscular imaging in inherited muscle diseases  

International Nuclear Information System (INIS)

Driven by increasing numbers of newly identified genetic defects and new insights into the field of inherited muscle diseases, neuromuscular imaging in general and magnetic resonance imaging (MRI) in particular are increasingly being used to characterise the severity and pattern of muscle involvement. Although muscle biopsy is still the gold standard for the establishment of the definitive diagnosis, muscular imaging is an important diagnostic tool for the detection and quantification of dystrophic changes during the clinical workup of patients with hereditary muscle diseases. MRI is frequently used to describe muscle involvement patterns, which aids in narrowing of the differential diagnosis and distinguishing between dystrophic and non-dystrophic diseases. Recent work has demonstrated the usefulness of muscle imaging for the detection of specific congenital myopathies, mainly for the identification of the underlying genetic defect in core and centronuclear myopathies. Muscle imaging demonstrates characteristic patterns, which can be helpful for the differentiation of individual limb girdle muscular dystrophies. The aim of this review is to give a comprehensive overview of current methods and applications as well as future perspectives in the field of neuromuscular imaging in inherited muscle diseases. We also provide diagnostic algorithms that might guide us through the differential diagnosis in hereditary myopathies. (orig.)

2010-01-01

313

Motor neuron, nerve, and neuromuscular junction disease.  

UK PubMed Central (United Kingdom)

PURPOSE OF REVIEW: The aim is to review the most relevant findings published during the last year concerning clinical, genetic, pathogenic, and therapeutic advances in motor neuron disease, neuropathies, and neuromuscular junction disorders. RECENT FINDINGS: Studies on animal and cell models have improved the understanding of how mutated survival motor neuron protein in spinal muscular atrophy governs the pathogenetic processes. New phenotypes of SOD1 mutations have been described. Moreover, animal models enhanced the insight into the pathogenetic background of sporadic and familial amyotrophic lateral sclerosis. Novel treatment options for motor neuron disease have been described in humans and animal models. Considerable progress has been achieved also in elucidating the genetic background of many forms of inherited neuropathies and high clinical and genetic heterogeneity has been demonstrated. Mutations in MuSK and GFTP1 have been shown to cause new types of congenital myasthenic syndromes. A third type of autoantibodies (Lrp4) has been detected to cause myasthenia gravis. SUMMARY: Advances in the clinical and genetic characterization of motor neuron diseases, neuropathies, and neuromuscular transmission defects have important implications on the fundamental understanding, diagnosis, and management of these disorders. Identification of crucial steps of the pathogenetic process may provide the basis for the development of novel therapeutic strategies.

Finsterer J; Papi? L; Auer-Grumbach M

2011-10-01

314

Electrophysiological study in neuromuscular junction disorders.  

UK PubMed Central (United Kingdom)

This review is on ultrastructure and subcellular physiology at normal and abnormal neuromuscular junctions. The clinical and electrophysiological findings in myasthenia gravis, Lambert-Eaton myasthenic syndrome (LEMS), congenital myasthenic syndromes, and botulinum intoxication are discussed. Single fiber electromyography (SFEMG) helps to explain the basis of testing neuromuscular junction function by repetitive nerve stimulation (RNS). SFEMG requires skill and patience and its availability is limited to a few centers. For RNS supramaximal stimulation is essential and so is display of the whole waveform of each muscle response at maximum amplitude. The amplitudes of the negative phase of the first and fourth responses are measured from baseline to negative peak, and the percent change of the fourth response compared with the first represents the decrement or increment. A decrement greater than 10% is accepted as abnormal and smooth progression of response amplitude train and reproducibility form the crux. In suspected LEMS the effect of fast rates of stimulation should be determined after RNS response to slow rates of stimulation. Caution is required to avoid misinterpretation of potentiation and pseudofacilitation.

Cherian A; Baheti NN; Iype T

2013-01-01

315

Neuromuscular imaging in inherited muscle diseases  

Energy Technology Data Exchange (ETDEWEB)

Driven by increasing numbers of newly identified genetic defects and new insights into the field of inherited muscle diseases, neuromuscular imaging in general and magnetic resonance imaging (MRI) in particular are increasingly being used to characterise the severity and pattern of muscle involvement. Although muscle biopsy is still the gold standard for the establishment of the definitive diagnosis, muscular imaging is an important diagnostic tool for the detection and quantification of dystrophic changes during the clinical workup of patients with hereditary muscle diseases. MRI is frequently used to describe muscle involvement patterns, which aids in narrowing of the differential diagnosis and distinguishing between dystrophic and non-dystrophic diseases. Recent work has demonstrated the usefulness of muscle imaging for the detection of specific congenital myopathies, mainly for the identification of the underlying genetic defect in core and centronuclear myopathies. Muscle imaging demonstrates characteristic patterns, which can be helpful for the differentiation of individual limb girdle muscular dystrophies. The aim of this review is to give a comprehensive overview of current methods and applications as well as future perspectives in the field of neuromuscular imaging in inherited muscle diseases. We also provide diagnostic algorithms that might guide us through the differential diagnosis in hereditary myopathies. (orig.)

Wattjes, Mike P. [VU University Medical Center, Department of Radiology, De Boelelaan 1117, HV, Amsterdam (Netherlands); Kley, Rudolf A. [Klinken Bergmannsheil, Ruhr-University, Department of Neurology, Neuromuscular Centre Ruhrgebiet, Bochum (Germany); Fischer, Dirk [University Hospital of Basel, Department of Neurology, Basel (Switzerland); University Children' s Hospital Basel, Department of Neuropaediatrics, Basel (Switzerland)

2010-10-15

316

Wordlength Estimation of Digital Controller Synthesis for Inkjet Printer Mechanism  

Directory of Open Access Journals (Sweden)

Full Text Available The effect of finite wordlength on coefficients in implementing discrete-time controllers has been a subject of many recent studies. Especially, this issue is more severe in the low budget consumer electronic products when a faster sample rate is desired. To save the cost of development, most of the manufacturers applied cheap processors on those kinds of products. Therefore, it is desired to develop an estimation method to predict the required wordlength while designing a controller. In this paper, we will focus our study on the controller synthesis for an inkjet printing mechanism and investigate the effect insufficient wordlength. We will also develop an algorithm to estimate the required resolution and apply the method to determine the required bits of wordlength for the controller designed.

Hung-Ming Cheng; Georgia T.-C. Chiu

2008-01-01

317

The Analysis on Financial Cooperative Controlling Mechanism of Enterprise Group  

Directory of Open Access Journals (Sweden)

Full Text Available As the core of modern market economy, enterprise group is an advanced form of organization after productive forces reached to a certain stage. For the reason of complexity and specificity of organizational form of enterprise group, the issue of financial cooperative control has been widespread concerned by theorists. Although many researches have been done, but there are still lacking of systematic research results especially in the fields of mechanism of financial cooperative control. After exploring the relationship of value effect and financial control, this paper puts forword a system model of financial cooperative control. It also gives a system analysis including system hierarchy analysis, synergy analysis and coupling analysis. All of these can provide a decision making support for the collaborative mana- gement of enterprise group.

Ziqin Feng

2010-01-01

318

INTERACTION OF VERAPAMIL AND LITHIUM AT THE NEUROMUSCULAR JUNCTION ON RAT ISOLATED MUSCLE-HEMIDIAPHRAGM  

Directory of Open Access Journals (Sweden)

Full Text Available It has been reported that cither lithium or verapamil can potentiate the neuromuscular blocking activity of certain neuromuscular blockers. In the present investigation, possible interaction of verapamil with lithium has been described. The dose ? response effects of verapamil and lithium on diaphragmatic contractility were assessed in vitro. Mechanical responses of the muscle to indirect (nerve) and direct (muscle) electrical stimulation were recorded. Verapamil depressed rat diaphragm twitch tensions induced by nerve stimulation in a dose - dependent manner with the 50 percent depression of the original twitch tensions (ICSQ) by 5.6 xlO^mmol/l."nThe IC50 of verapamil for direct stimulation of the muscle was LI x W'5 mmol II. Partial replacement of sodium chloride by lithium chloride (0.5, 1.5 and 5 mmol /1) in the medium did not change the depressant effect of verapamil on muscle twitches induced by direct (muscle) or indirect (nerve) electrical stimulation.

H. R. Sadeghipour; M. Mesbahian1 A.R. Dehpour

1998-01-01

319

Microfluidic primary culture model of the lower motor neuron-neuromuscular junction circuit.  

Science.gov (United States)

Modelling the complex process of neuromuscular signalling is key to understanding not only normal circuit function but also importantly the mechanisms underpinning a range of degenerative diseases. We describe a novel in vitro model of the lower motor neuron-neuromuscular junction circuit, incorporating primary spinal motor neurons, supporting glia and skeletal muscle. This culture model is designed to spatially mimic the unique anatomical and cellular interactions of this circuit in compartmented microfluidic devices, such that the glial cells are located with motor neuron cell bodies in the cell body chamber and motor neuron axons extend to a distal chamber containing skeletal muscle cells whilst simultaneously allowing targeted intervention. This model is suitable for use in conjunction with a range of downstream experimental approaches and could also be modified to utilise other cellular sources including appropriate immortal cell lines, cells derived from transgenic models of disease and also patient derived stem cells. PMID:23774648

Southam, Katherine A; King, Anna E; Blizzard, Catherine A; McCormack, Graeme H; Dickson, Tracey C

2013-06-14

320

[Effect of hydrocortisone on neuromuscular transmission in the frog skeletal muscles].  

Science.gov (United States)

Hydrocortisone (1.10(-7)-1.10(-5) M/l) in vitro experiments on frog's muscle in conditions of preliminary curarization increases dose-dependently the quantum content of e.p.p., affecting neither membrane potential, nor input resistance, nor sensitivity to acetylcholine of the membrane of m. sartorius fibers. Hydrocortisone in conditions of magnesium block of neuro-muscular transmission does not affect the evoked transmission. Hydrocortisone seems to facilitate the evoked quantum acetylcholine secretion only in the presence of curare and in conditions of initial high quantum content of e.p.p. The mechanism of hydrocortisone decurarization effect on neuro-muscular transmission is mainly of a presynaptic nature. PMID:2987046

Poletaev, G I; Volkov, E M; Akhtiatova, D A; Chikin, A V

1985-04-01

 
 
 
 
321

[Effect of hydrocortisone on neuromuscular transmission in the frog skeletal muscles  

UK PubMed Central (United Kingdom)

Hydrocortisone (1.10(-7)-1.10(-5) M/l) in vitro experiments on frog's muscle in conditions of preliminary curarization increases dose-dependently the quantum content of e.p.p., affecting neither membrane potential, nor input resistance, nor sensitivity to acetylcholine of the membrane of m. sartorius fibers. Hydrocortisone in conditions of magnesium block of neuro-muscular transmission does not affect the evoked transmission. Hydrocortisone seems to facilitate the evoked quantum acetylcholine secretion only in the presence of curare and in conditions of initial high quantum content of e.p.p. The mechanism of hydrocortisone decurarization effect on neuro-muscular transmission is mainly of a presynaptic nature.

Poletaev GI; Volkov EM; Akhtiatova DA; Chikin AV

1985-04-01

322

Microfluidic primary culture model of the lower motor neuron-neuromuscular junction circuit.  

UK PubMed Central (United Kingdom)

Modelling the complex process of neuromuscular signalling is key to understanding not only normal circuit function but also importantly the mechanisms underpinning a range of degenerative diseases. We describe a novel in vitro model of the lower motor neuron-neuromuscular junction circuit, incorporating primary spinal motor neurons, supporting glia and skeletal muscle. This culture model is designed to spatially mimic the unique anatomical and cellular interactions of this circuit in compartmented microfluidic devices, such that the glial cells are located with motor neuron cell bodies in the cell body chamber and motor neuron axons extend to a distal chamber containing skeletal muscle cells whilst simultaneously allowing targeted intervention. This model is suitable for use in conjunction with a range of downstream experimental approaches and could also be modified to utilise other cellular sources including appropriate immortal cell lines, cells derived from transgenic models of disease and also patient derived stem cells.

Southam KA; King AE; Blizzard CA; McCormack GH; Dickson TC

2013-09-01

323

The influence of gender on neuromuscular pre-activity during side-cutting  

DEFF Research Database (Denmark)

It is well established that female athletes are at increased risk for sustaining ACL injuries in sports, where sudden changes of direction are a frequent movement pattern. The underlying neuromuscular mechanisms related to the elevated ACL injury rate in female athletes has yet to be fully investigated. This cross-sectional study aimed to examine gender differences in neuromuscular pre-activity during a maneuver that mimics a movement associated with the incidence of ACL injuries. Twenty-four team handball players (12 male and 12 female) with no history of ACL injury were tested for EMG pre-activity of vastus lateralis, vastus medialis, semitendinosus, and biceps femoris during a side-cutting maneuver. Mean EMG amplitude 50ms prior to toe down was normalized to maximal EMG obtained during maximal isometric contraction. The results showed that females had significantly lower hamstring EMG pre-activity 50ms prior to toe-down than males (P

Bencke, Jesper; Zebis, Mette K

2011-01-01

324

Inherited neuromuscular diseases in the mouse: a review of the literature/ Doenças neuromusculares hereditárias em camundongos: revisão da literatura  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese Existem inúmeras doenças neuromusculares que acometem seres humanos. A grande maioria delas é insuficientemente conhecida quanto a mecanismos fisiopatológicos e tratamentos adequados. A limitação na manipulação experimental em «anima nobili» faz-nos procurar meios alternativos para o estudo dessas doenças, tais como animais experimentais com distúrbios neuromusculares geneticamente transmitidos. Estes mutantes constituem fonte inesgotável e valiosa de informa (more) ções quanto a mecanismos fisiopatogênicos e processos patológicos básicos em doenças neuromusculares. Entre as diversas espécies animais afetadas por distúrbios neuromusculares o camundongo é de particular interesse devido ao seu baixo custo de manutenção, rápida reprodutividade e pequeno tamanho, o que permite amplos estudos morfológicos a custos acessíveis. Nesta revisão analisamos 20 camundongos mutantes com distúrbios afetando nervo periférico, músculo esquelético ou junção neuromuscular. Aspectos genéticos, clínicos e patológicos são discutidos na intenção de oferecer informação atualizada sobre essas mutações animais, muitas das quais de. grande interesse como modelos experimentais de doenças neuromusculares humanas. Abstract in english There are several neuromuscular disorders affecting the human being. Most of these are poorly understood and lack an effective treatment. Due to the limitation of experimental manipulation in «anima nobili», inherited neuromuscular diseases in laboratory animals constitute a valuable source of scientific information. Amongst several animal species affected by neuromuscular disorders the house mouse is of particular interest because of its small size, short pregnancy and (more) low costs of maintanence. In the present review 20 murine mutants with diseases affecting peripheral nerves, skeletal muscles and motor end-plates are tabulated. Genetic, clinical and pathological aspects are discussed aiming to provide information about these mutants which might be of great interest as animal models for human neuromuscular diseases.

Torres, Luiz Fernando Bleggi

1988-09-01

325

Mechanisms in Adaptive Feedback Control: Photoisomerization in a Liquid  

CERN Multimedia

The underlying mechanism for Adaptive Feedback Control in the experimental photoisomerization of NK88 in methanol is exposed theoretically. With given laboratory limitations on laser output, the complicated electric fields are shown to achieve their targets in qualitatively simple ways. Further, control over the cis population without laser limitations reveals an incoherent pump-dump scenario as the optimal isomerization strategy. In neither case are there substantial contributions from quantum multiple-path interference or from nuclear wavepacket coherence. Environmentally induced decoherence is shown to justify the use of a simplified theoretical model.

Hoki, K; Hoki, Kunihito; Brumer, Paul

2005-01-01

326

Fine Voltage Control Using Oltc by Static Tap Change Mechanism  

Directory of Open Access Journals (Sweden)

Full Text Available In this paper, a novel model of fully electronic on load semiconductor tap changer for power transformer has been proposed. With high power semiconductor devices, problems associated with conventional mechanical on load tap changers which includes excessive conduction losses and arcing in the diverter switch have been properly rectified. In this work Simulink model was designed with GTOs as switching devices embedded in taps. Step change of voltage is achieved changing taps by switching GTOs and fine voltage with error less than ±0.1% is obtained by sequential firing control between GTOs in the system, which is not possible in conventional automatic OLTC control system.

S.V.M. Bhuvanaika rao , B.Subramanyeswar

2012-01-01

327

Quality control of injection moulded micro mechanical parts  

DEFF Research Database (Denmark)

Quality control of micro components is an increasing challenge. Smaller mechanical parts are characterized by smaller tolerance to be verified. This paper focuses on the dimensional verification of micro injection moulded components selected from an industrial application. These parts are measured using an Optical Coordinate Measuring Machine (OCMM), which guarantees fast surface scans suitable for in line quality control. The uncertainty assessment of the measurements is calculated following the substitution method. To investigate the influence parameters in optical coordinate metrology two analyses are carried out and discussed. The estimation of the total variability of optical measurements and instrument repeatability are reported.

Gasparin, Stefania; Tosello, Guido

2009-01-01

328

Optimal Control of Underactuated Mechanical Systems: A Geometric Approach  

CERN Multimedia

In this paper, we consider a geometric formalism for optimal control of underactuated mechanical systems. Our techniques are an adaptation of the classical Skinner and Rusk approach for the case of Lagrangian dynamics with higher-order constraints. We study a regular case where it is possible to establish a symplectic framework and, as a consequence, to obtain a unique vector field determining the dynamics of the optimal control problem. These developments will allow us to develop a new class of geometric integrators based on discrete variational calculus.

Colombo, L; Zuccalli, M

2009-01-01

329

Understanding the in vitro neuromuscular activity of snake venom Lys49 phospholipase A2 homologues.  

UK PubMed Central (United Kingdom)

Phospholipases A(2) (PLA(2)s) with a lysine substituting for the highly conserved aspartate 49, Lys49 PLA(2) homologues, are important myotoxic components in venoms from snakes of Viperidae family. These proteins induce conspicuous myonecrosis by a catalytically-independent mechanism. Traditionally, the Lys49 PLA(2) homologues are classified as non-neurotoxic myotoxins given their inability to cause lethality or paralytic effects when injected in vivo, even at relatively high doses. However, a series of in vitro studies has shown that several Lys49 PLA(2) homologues from Bothrops snake venoms induce neuromuscular blocking activity on nerve-muscle preparations in vitro. The interpretation of these findings has created some confusion in the literature, raising the question whether the Lys49 PLA(2) homologues present some neurotoxic activity. The present article reviews the in vitro neuromuscular effects of Lys49 PLA(2) homologues and discusses their possible mechanisms of action. It was concluded that the neuromuscular blockade induced by Lys49 PLA(2) homologues in isolated preparations is mainly a consequence of the general membrane-destabilizing effect of these toxins.

Gallacci M; Cavalcante WL

2010-01-01

330

Biogeochemical Mechanisms Controlling Reduced Radionuclide Particle Properties and Stability  

Energy Technology Data Exchange (ETDEWEB)

Uranium and Technetium are the major risk-driving contaminants at Hanford and other DOE sites. These radionuclides have been shown to be reduced by dissimilatory metal reducing bacteria (DMRB) under anoxic conditions. Laboratory studies have demonstrated that reduction results in the formation of poorly soluble hydrous oxides, UO2(s) and TcO2n?H2O(s), that are believed to limit mobility in the environment. The mechanisms of microbial reduction of U and Tc have been the focus of considerable research in the Environmental Remediation Sciences Program (ERSP). In spite of equal or greater importance in terms of controlling the environmental fate of the contaminants relatively little is known regarding the precipitation mechanism(s), reactivity, persistence, and transport of biogenic UO2(s) and TcO2(s).

Jim K. Fredrickson; John M. Zachara; Matthew J. Marshall; Alex S. Beliaev

2006-06-01

331

Invasive mechanism and control strategy of Ageratina adenophora (Sprengel).  

Science.gov (United States)

In order to ascertain the invasive mechanism and control strategy of the invasive Crofton weed, Ageratina adenophora, its ecological adaptability and population differentiation, the formation of single dominant population, displacement of native plants and sustainable management strategies were investigated. The present results helped to clarify and explain such issues as the adaptability post invasion, interaction and competition between inter- and intra-species and community resistance, thereby providing important references to researches on other invasive alien species. PMID:21046320

Wan, FangHao; Liu, WanXue; Guo, JianYing; Qiang, Sheng; Li, BaoPing; Wang, JinJun; Yang, GuoQing; Niu, HongBang; Gui, FuRong; Huang, WenKun; Jiang, ZhiLin; Wang, WenQi

2010-11-03

332

A fine-control and safety mechanism for fast reactors  

International Nuclear Information System (INIS)

Improvements are described, according to which the means for suspending the absorbing element is preferably a so-called calibrated chain. The coupling means can be an electro-magnet, the conductive wire of which is coated with a magnesia layer outwardly protected by a sheath of refractory material. This can be applied to the manufacture of small-sized fine-control and safety mechanisms for fast reactors

1973-01-01

333

Experience with control rod drive mechanism of FBTR  

International Nuclear Information System (INIS)

[en] This paper explains the principle of operation of Control Rod Drive Mechanism (CRDM) in Fast Breeder Test Reactor (FBTR) which is a 40 MWt loop type reactor. It discusses the problems faced and solutions evolved during testing of CRDM in air and in sodium and during operation in reactor. Surveillance tests carried out with CRDMs in pile are also discussed. (author). 2 figs

1996-01-01

334

Improving CRDM (Control Rod Drive Mechanism) penetration inspection  

International Nuclear Information System (INIS)

[en] Since a through-wall longitudinal crack in a reactor vessel head penetration was discovered in September 1991, considerable efforts have been spent on developing techniques and equipment to detect such defects early. ABB claims to be the first company to have provided equipment and methods to carry out remote inspection of control rod drive mechanisms (CRDMs) and is still improving and extending its services. (author)

1995-01-01

335

Controlling chaotic orbits in mechanical systems with impacts  

Energy Technology Data Exchange (ETDEWEB)

We stabilize desired unstable periodic orbits, embedded in the chaotic invariant sets of mechanical systems with impacts, by applying a small and precise perturbation on an available control parameter. To obtain such perturbation numerically, we introduce a transcendental map (impact map) for the dynamical variables computed just after the impacts. To show how to implement the method, we apply it to an impact oscillator and to an impact-pair system.

Souza, Silvio L.T. de E-mail: thomaz@if.usp.br; Caldas, Ibere L. E-mail: ibere@if.usp.br

2004-01-01

336

Distinct mechanisms control contrast adaptation over different timescales.  

UK PubMed Central (United Kingdom)

Changes to the visual environment can happen at many timescales, from very transient to semi-permanent. To adapt optimally, the visual system also adjusts at different timescales, with longer-lasting environmental changes producing longer-lasting effects, but how the visual system adapts in this way remains unknown. Here, we show that contrast adaptation-the most-studied form of visual adaptation-has multiple controllers, each operating over a different time scale. In a series of experiments, subjects completed either a contrast matching, contrast detection, or tilt adjustment task, while adapting to contrast at one orientation. Following a relatively longer period (5 min) of adaptation to high contrast, subjects were "deadapted" for a shorter period (e.g., 40 s) to a lower contrast. Deadaptation eliminated perceptual aftereffects of adaptation, but continued testing in a neutral environment revealed their striking recovery. These results suggest the following account: Adaptation was controlled by at least two mechanisms, with initial adaptation affecting a longer-term one and deadaptation affecting a shorter-term one in the opposite direction. Immediately following deadaptation, the effects of the two mechanisms cancelled each other, but the short-term effects rapidly decayed, revealing ongoing longer-term adaptation. A single controlling mechanism cannot account for the observed recovery of effects, since once deadaptation cancels the initial longer-term adaptation, no trace of it remains. Combined with previous results at very long adaptation durations, the present results suggest that contrast adaptation is possibly controlled by a continuum of mechanisms acting over a large range of timescales.

Bao M; Fast E; Mesik J; Engel S

2013-01-01

337

Invasive mechanism and control strategy of Ageratina adenophora (Sprengel).  

UK PubMed Central (United Kingdom)

In order to ascertain the invasive mechanism and control strategy of the invasive Crofton weed, Ageratina adenophora, its ecological adaptability and population differentiation, the formation of single dominant population, displacement of native plants and sustainable management strategies were investigated. The present results helped to clarify and explain such issues as the adaptability post invasion, interaction and competition between inter- and intra-species and community resistance, thereby providing important references to researches on other invasive alien species.

Wan F; Liu W; Guo J; Qiang S; Li B; Wang J; Yang G; Niu H; Gui F; Huang W; Jiang Z; Wang W

2010-11-01

338

Evaluation of skeletal muscular involvement in neuromuscular disorders with thallium-201 whole body scintigraphy  

International Nuclear Information System (INIS)

[en] The extent as well as severity of pathologic changes of skeletal muscles were analyzed with thallium-201 whole body scintigraphy (WBS) in 29 cases of various types of neuromuscular diseases (18 cases of myogenic and 11 cases of neurogenic muscular diseases) and 14 cases of normal controls. After intravenous injection of 2 mCi of thallium-201 chloride, WBS was performed for 15 minutes using a gamma camera with twin-opposed large rectangular detectors. Counts at brachia, forearms, thighs, and calves were assessed after reconstruction of the scintigram of the whole body by taking the geometric mean of the anterior and posterior data. WBS showed uniform tracer activities in the 4 extremities in 12 cases among 14 controls. Laterality in distribution of counts of both legs and arms was noted in the remaining 2 controls. WBS revealed decrease of perfusion in the extremities with muscular atrophy and/or weakness in neuromuscular diseases. The overall diagnostic accuracy of WBS for evaluation of skeletal muscle involvement was 75 to 80 % except for the bilateral brachia for which it decreased to 65 %. All of the three cases of muscular dystrophy with pseudohypertrophy of the calves or thighs showed unequivocal decrease of perfusion of those regions in WBS. In conclusion, thallium-201 WBS was considered to be a useful clinical means in evaluating the extent and severity of muscular involvement of various types of neuromuscular disorders. (author)

1986-01-01

339

Consecuencias clínicas de las alteraciones neuromusculares en el paciente crítico Clinical consequences of neuromuscular impairments in critically ill patients  

Directory of Open Access Journals (Sweden)

Full Text Available La patología neuromuscular en el paciente crítico se desarrolla en dos contextos: enfermedades neurológicas primarias que requieren su ingreso en Medicina Intensiva por necesitar vigilancia estricta o ventilación mecánica y manifestaciones del sistema nervioso periférico secundarias a enfermedades sistémicas críticas. En el primer grupo son las más frecuentes el Síndrome de Guillain-Barré y la Miastenia Gravis y en el segundo la Polineuropatía y la Miopatía del paciente crítico. El patrón clínico común más frecuente consiste en el desarrollo de un cuadro de acusada debilidad y cuadriparesia cuya manifestación más típica es la necesidad de respiración asistida o la dificultad/imposibilidad para su retirada. Se consideran factores desencadenantes el fracaso multiorgánico y la sepsis en la polineuropatía y los esteroides y bloqueantes neuromusculares en la miopatía, actuando como coadyuvantes en ambos casos la malnutrición, particularmente la hipoalbimunemia, y la hiperglucemia. Considerando que la afectación neuropática y miopática coexisten con frecuencia, se ha acuñado el término polineuromiopatía del paciente crítico. Tanto el Síndrome de Guillain-Barré como la polineuropatía del paciente crítico se localizan a nivel del nervio periférico, por lo que debe efectuarse un diagnóstico diferencial entre ambos. La forma de presentación es diferente ya que el primero es una patología aguda que motiva su ingreso en UCI, mientras que la polineuropatía se adquiere durante la hospitalización. En el primero es frecuente la afectación del sistema nervioso autónomo y la disociación albúmino-citológica en el LCR, lo que no se da en la polineuropatía. Los estudios electrofisiológicos muestran signos de desmelinización con disminución de la velocidad de conducción y normalidad en la amplitud de potenciales motores en el Síndrome de Guillain- Barré frente a velocidad de conducción normal y amplitud reducida de potenciales motores en la polineuropatía axonal. La crisis miasténica afecta a la unión neuromuscular y su diagnóstico suele ser más fácil al tener en la mayoría de los casos un diagnóstico previo de miastenia gravis.La debilidad muscular aumenta durante la actividad repetida (fatiga muscular) y mejora con el reposo. Su confirmación diagnóstica se realiza con el test del edofronio y con la estimulación nerviosa repetitiva, que provoca una rápida disminución del 10-15% en la amplitud de las respuestas provocadas. La miopatía del paciente crítico se localiza en el músculo y provoca una debilidad generalizada con cuadriparesia, muy similar a la de la polineuropatía, que impide o retrasa la desconexión de la ventilación mecánica y que en sus grados avanzados puede provocar un aumento de CPK y mioglobina, junto con alteraciones en la exploración neurofisiológica. Esta última es difícil de discernir de la encontrada en la polineuropatía, aunque la normalidad en los potenciales de acción sensitiva y la redución en el potencial de ación motora con estimulación muscular directa, puede ayudar a diferenciarlos. El pronóstico funcional de las alteraciones musculares primarias suele ser bastante bueno, pero tanto la polineuropatía como la miopatía evolucionan lentamente a lo largo de semanas o meses, pudiendo quedar un importante déficit residual a los dos años en los casos más graves.Neuromuscular pathology in the critically ill patient develops within two settings: primary neurological diseases that require admission in the Intensive Care Medicine Unit for close monitoring or mechanical ventilation, and peripheral nervous system manifestations secondary to critical systemic diseases. The most frequent conditions in the first group are Guillain-Barré syndrome and Myasthenia Gravis, and in the second group, polyneuropathy and myopathy of the critically ill patient. The most commonly shared clinical pattern is the development of severe weakness and quadriplegia which most typical manifestation is the need for assisted ventilation and/o

A. Mesejo; E. Pérez-Sancho; E. Moreno

2006-01-01

340

Consecuencias clínicas de las alteraciones neuromusculares en el paciente crítico/ Clinical consequences of neuromuscular impairments in critically ill patients  

Scientific Electronic Library Online (English)

Full Text Available Abstract in spanish La patología neuromuscular en el paciente crítico se desarrolla en dos contextos: enfermedades neurológicas primarias que requieren su ingreso en Medicina Intensiva por necesitar vigilancia estricta o ventilación mecánica y manifestaciones del sistema nervioso periférico secundarias a enfermedades sistémicas críticas. En el primer grupo son las más frecuentes el Síndrome de Guillain-Barré y la Miastenia Gravis y en el segundo la Polineuropatía y la Miopatía d (more) el paciente crítico. El patrón clínico común más frecuente consiste en el desarrollo de un cuadro de acusada debilidad y cuadriparesia cuya manifestación más típica es la necesidad de respiración asistida o la dificultad/imposibilidad para su retirada. Se consideran factores desencadenantes el fracaso multiorgánico y la sepsis en la polineuropatía y los esteroides y bloqueantes neuromusculares en la miopatía, actuando como coadyuvantes en ambos casos la malnutrición, particularmente la hipoalbimunemia, y la hiperglucemia. Considerando que la afectación neuropática y miopática coexisten con frecuencia, se ha acuñado el término polineuromiopatía del paciente crítico. Tanto el Síndrome de Guillain-Barré como la polineuropatía del paciente crítico se localizan a nivel del nervio periférico, por lo que debe efectuarse un diagnóstico diferencial entre ambos. La forma de presentación es diferente ya que el primero es una patología aguda que motiva su ingreso en UCI, mientras que la polineuropatía se adquiere durante la hospitalización. En el primero es frecuente la afectación del sistema nervioso autónomo y la disociación albúmino-citológica en el LCR, lo que no se da en la polineuropatía. Los estudios electrofisiológicos muestran signos de desmelinización con disminución de la velocidad de conducción y normalidad en la amplitud de potenciales motores en el Síndrome de Guillain- Barré frente a velocidad de conducción normal y amplitud reducida de potenciales motores en la polineuropatía axonal. La crisis miasténica afecta a la unión neuromuscular y su diagnóstico suele ser más fácil al tener en la mayoría de los casos un diagnóstico previo de miastenia gravis.La debilidad muscular aumenta durante la actividad repetida (fatiga muscular) y mejora con el reposo. Su confirmación diagnóstica se realiza con el test del edofronio y con la estimulación nerviosa repetitiva, que provoca una rápida disminución del 10-15% en la amplitud de las respuestas provocadas. La miopatía del paciente crítico se localiza en el músculo y provoca una debilidad generalizada con cuadriparesia, muy similar a la de la polineuropatía, que impide o retrasa la desconexión de la ventilación mecánica y que en sus grados avanzados puede provocar un aumento de CPK y mioglobina, junto con alteraciones en la exploración neurofisiológica. Esta última es difícil de discernir de la encontrada en la polineuropatía, aunque la normalidad en los potenciales de acción sensitiva y la redución en el potencial de ación motora con estimulación muscular directa, puede ayudar a diferenciarlos. El pronóstico funcional de las alteraciones musculares primarias suele ser bastante bueno, pero tanto la polineuropatía como la miopatía evolucionan lentamente a lo largo de semanas o meses, pudiendo quedar un importante déficit residual a los dos años en los casos más graves. Abstract in english Neuromuscular pathology in the critically ill patient develops within two settings: primary neurological diseases that require admission in the Intensive Care Medicine Unit for close monitoring or mechanical ventilation, and peripheral nervous system manifestations secondary to critical systemic diseases. The most frequent conditions in the first group are Guillain-Barré syndrome and Myasthenia Gravis, and in the second group, polyneuropathy and myopathy of the criticall (more) y ill patient. The most commonly shared clinical pattern is the development of severe weakness and quadriplegia which most typical

Mesejo, A.; Pérez-Sancho, E.; Moreno, E.

2006-05-01

 
 
 
 
341

Insuficiência respiratória crônica nas doenças neuromusculares: diagnóstico e tratamento Chronic respiratory failure in patients with neuromuscular diseases: diagnosis and treatment  

Directory of Open Access Journals (Sweden)

Full Text Available As doenças neuromusculares prejudicam a renovação do ar alveolar e, por esta razão, produzem insuficiência respiratória crônica. A instalação da insuficiência respiratória pode acontecer de modo agudo, como nos traumas, ou ser lenta ou rapidamente progressiva, como na esclerose lateral amiotrófica, distrofias musculares, doença da placa mioneural, etc. O comprometimento da musculatura respiratória prejudica também a eficiência da tosse e, no estado atual da terapêutica disponível no Brasil para estes doentes, pode-se dizer que a morbimortalidade nestes indivíduos está mais associada ao fato de que eles tossem mal do que de que ventilam mal. Nesta revisão, uma breve compilação histórica procura mostrar a evolução das órteses e próteses respiratórias, desde o final do século XIX até agora, com o objetivo de apresentar as opções de máquinas disponíveis para o suporte e substituição da ventilação nas doenças neuromusculares. Além disso, são enfatizados os elementos fundamentais para o diagnóstico da hipoventilação alveolar e da falência do mecanismo protetor da tosse: história clínica, determinação do pico de fluxo da tosse, medida da pressão expiratória máxima e da pressão inspiratória máxima, espirometria em dois decúbitos (sentado e supino), oximetria de pulso, capnografia e polissonografia. São apresentados os valores limites disponíveis na literatura tanto para a indicação do suporte noturno da ventilação como para a extensão do suporte para o período diurno. As manobras para incremento da eficiência da tosse são aqui também discutidas, assim como o momento adequado para sua introdução.Neuromuscular diseases affect alveolar air exchange and therefore cause chronic respiratory failure. The onset of respiratory failure can be acute, as in traumas, or progressive (slow or rapid), as in amyotrophic lateral sclerosis, muscular dystrophies, diseases of the myoneural junction, etc. Respiratory muscle impairment also affects cough efficiency and, according to the current knowledge regarding the type of treatment available in Brazil to these patients, it can be said that the high rates of morbidity and mortality in these individuals are more often related to the fact that they cough inefficiently rather than to the fact that they ventilate poorly. In this review, with the objective of presenting the options of devices available to support and substitute for natural ventilation in patients with neuromuscular diseases, we have compiled a brief history of the evolution of orthopedic braces and prostheses used to aid respiration since the end of the 19th century. In addition, we highlight the elements that are fundamental to the diagnosis of alveolar hypoventilation and of failure of the protective cough mechanism: taking of a clinical history; determination of peak cough flow; measurement of maximal inspiratory and expiratory pressures; spirometry in two positions (sitting and supine); pulse oximetry; capnography; and polysomnography. Furthermore, the threshold values available in the literature for the use of nocturnal ventilatory support and for the extension of this support through the daytime period are presented. Moreover, the maneuvers used to increase cough efficiency, as well as the proper timing of their introduction, are discussed.

Ilma Aparecida Paschoal; Wander de Oliveira Villalba; Mônica Corso Pereira

2007-01-01

342

Insuficiência respiratória crônica nas doenças neuromusculares: diagnóstico e tratamento/ Chronic respiratory failure in patients with neuromuscular diseases: diagnosis and treatment  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese As doenças neuromusculares prejudicam a renovação do ar alveolar e, por esta razão, produzem insuficiência respiratória crônica. A instalação da insuficiência respiratória pode acontecer de modo agudo, como nos traumas, ou ser lenta ou rapidamente progressiva, como na esclerose lateral amiotrófica, distrofias musculares, doença da placa mioneural, etc. O comprometimento da musculatura respiratória prejudica também a eficiência da tosse e, no estado atual d (more) a terapêutica disponível no Brasil para estes doentes, pode-se dizer que a morbimortalidade nestes indivíduos está mais associada ao fato de que eles tossem mal do que de que ventilam mal. Nesta revisão, uma breve compilação histórica procura mostrar a evolução das órteses e próteses respiratórias, desde o final do século XIX até agora, com o objetivo de apresentar as opções de máquinas disponíveis para o suporte e substituição da ventilação nas doenças neuromusculares. Além disso, são enfatizados os elementos fundamentais para o diagnóstico da hipoventilação alveolar e da falência do mecanismo protetor da tosse: história clínica, determinação do pico de fluxo da tosse, medida da pressão expiratória máxima e da pressão inspiratória máxima, espirometria em dois decúbitos (sentado e supino), oximetria de pulso, capnografia e polissonografia. São apresentados os valores limites disponíveis na literatura tanto para a indicação do suporte noturno da ventilação como para a extensão do suporte para o período diurno. As manobras para incremento da eficiência da tosse são aqui também discutidas, assim como o momento adequado para sua introdução. Abstract in english Neuromuscular diseases affect alveolar air exchange and therefore cause chronic respiratory failure. The onset of respiratory failure can be acute, as in traumas, or progressive (slow or rapid), as in amyotrophic lateral sclerosis, muscular dystrophies, diseases of the myoneural junction, etc. Respiratory muscle impairment also affects cough efficiency and, according to the current knowledge regarding the type of treatment available in Brazil to these patients, it can be (more) said that the high rates of morbidity and mortality in these individuals are more often related to the fact that they cough inefficiently rather than to the fact that they ventilate poorly. In this review, with the objective of presenting the options of devices available to support and substitute for natural ventilation in patients with neuromuscular diseases, we have compiled a brief history of the evolution of orthopedic braces and prostheses used to aid respiration since the end of the 19th century. In addition, we highlight the elements that are fundamental to the diagnosis of alveolar hypoventilation and of failure of the protective cough mechanism: taking of a clinical history; determination of peak cough flow; measurement of maximal inspiratory and expiratory pressures; spirometry in two positions (sitting and supine); pulse oximetry; capnography; and polysomnography. Furthermore, the threshold values available in the literature for the use of nocturnal ventilatory support and for the extension of this support through the daytime period are presented. Moreover, the maneuvers used to increase cough efficiency, as well as the proper timing of their introduction, are discussed.

Paschoal, Ilma Aparecida; Villalba, Wander de Oliveira; Pereira, Mônica Corso

2007-02-01

343

Rate-Controlling Mechanisms in Five-Power-Law Creep  

Energy Technology Data Exchange (ETDEWEB)

OAK-B135 Rate-Controlling Mechanisms in Five-Power-Law Creep. The initial grant emphasized the rate-controlling processes for five power-law creep. The effort has six aspects: (1) Theory of Taylor hardening from the Frank dislocation network in five power law substructures. (2) The dual dynamical and hardening nature of dislocations in five power law substructures. (3) Determination of the existence of long-range internal stress in five-power law creep dislocation substructures. (4) Dynamic recovery mechanisms associated with dislocation heterogeneities during five power law creep. (5) Versatility of five power law creep concept to other (hcp) crystal structures. (6) Writing of a book on ''Fundamental of Creep in Metals and Alloys'' by M.E. Kassner and Maria-Teresa Perez-Frado (postdoctoral scholar, funded by this project) Elsevier Press, 2004, in press. These areas are consistent with the original goals of this project as delineated in the original proposal to Basic Energy Sciences. The progress in each of these areas will be discussed separately and there will be an attempt to tie each aspect together so as to allow a summary regarding the conclusions with respect to the rate-controlling mechanisms of five power-law creep.

Michael E. Kassner

2004-04-20

344

COMPARATIVE ANALYSIS OF CONGESTION CONTROL MECHANISMS IN HIGH SPEED NETWORK  

Directory of Open Access Journals (Sweden)

Full Text Available : In this paper an effort has been made to study various Congestion control techniques that are used for reducing/easing the level of congestion and subsequently avoiding the congestion of the wired communication networks in general and High Speed Networks in particular. Many authors have suggested several congestion control techniques such as “TCP Congestion control”, Increase and algorithms”, “Congestion avoidance and control”, “Equation-Based Congestion Control for Unicast Application”, “Random Early Detection Gateways for Congestion Avoidance”, “New Techniques for congestion Control Detection and Avoidance”, “A Binary feedback scheme for Congestion Avoidance in Computer”, “Understanding CHOKe: Throughput and spatial characteristics” & “FAST TCP: Motivation Architecture Algorithm Performance” and studied their behavior under various network conditions, for a range of parameters also under heterogeneous networking environments. A special effort has been made to study the problems associated with the TCP congestion control mechanisms and the several solutions that have been proposed to improve its performance. This analysis tries to study the limitations of the suggested solutions, based on various parameters and propose algorithms to overcome these limitations for the High Speed Networks.

Chander Kant

2012-01-01

345

Mechanical control of cation channels in the myogenic response.  

UK PubMed Central (United Kingdom)

Microcirculatory vessel response to changes in pressure, known as the myogenic response, is a key component of a tissue's ability to regulate blood flow. Experimental studies have not clearly elucidated the mechanical signal in the vessel wall governing steady-state reduction in vessel diameter upon an increase in intraluminal pressure. In this study, a multiscale computational model is constructed from established models of vessel wall mechanics, vascular smooth muscle (VSM) force generation, and VSM Ca(2+) handling and electrophysiology to compare the plausibility of vessel wall stress or strain as an effective mechanical signal controlling steady-state vascular contraction in the myogenic response. It is shown that, at the scale of a resistance vessel, wall stress, and not stretch (strain), is the likely physiological signal controlling the steady-state myogenic response. The model is then used to test nine candidate VSM stress-controlled channel variants by fitting two separate sets of steady-state myogenic response data. The channel variants include nonselective cation (NSC), supplementary Ca(2+) and Na(+), L-type Ca(2+), and large conductance Ca(2+)-activated K(+) channels. The nine variants are tested in turn, and model fits suggest that stress control of Ca(2+) or Na(+) influx through NSC, supplementary Ca(2+) or Na(+), or L-type Ca(2+) channels is sufficient to produce observed steady-state diameter changes with pressure. However, simulations of steady-state VSM membrane potential, cytosolic Ca(2+), and Na(+) with pressure show only that Na(+) influx through NSC channel also generates known trends with increasing pressure, indicating that stress-controlled Na(+) influx through NSC is sufficient to generate the myogenic response.

Carlson BE; Beard DA

2011-08-01

346

Neuromuscular blockade in cardiac surgery: An update for clinicians  

Directory of Open Access Journals (Sweden)

Full Text Available There have been great advancements in cardiac surgery over the last two decades; the widespread use of off-pump aortocoronary bypass surgery, minimally invasive cardiac surgery, and robotic surgery have also changed the face of cardiac anaesthesia. The concept of "Fast-track anaesthesia" demands the use of nondepolarising neuromuscular blocking drugs with short duration of action, combining the ability to provide (if necessary) sufficiently profound neuromuscular blockade during surgery and immediate re-establishment of normal neuromuscular transmission at the end of surgery. Postoperative residual muscle paralysis is one of the major hurdles for immediate or early extubation after cardiac surgery. Nondepolarising neuromuscular blocking drugs for cardiac surgery should therefore be easy to titrate, of rapid onset and short duration of action with a pathway of elimination independent from hepatic or renal dysfunction, and should equally not affect haemodynamic stability. The difference between repetitive bolus application and continuous infusion is outlined in this review, with the pharmacodynamic and pharmacokinetic characteristics of vecuronium, pancuronium, rocuronium, and cisatracurium. Kinemyography and acceleromyography are the most important currently used neuromuscular monitoring methods. Whereas monitoring at the adductor pollicis muscle is appropriate at the end of surgery, monitoring of the corrugator supercilii muscle better reflects neuromuscular blockade at more central, profound muscles, such as the diaphragm, larynx, or thoraco-abdominal muscles. In conclusion, cisatracurium or rocuronium is recommended for neuromuscular blocka