Reversible inactivation of macaque frontal eye field.

The macaque frontal eye field (FEF) is involved in the generation of saccadic eye movements and fixations. To better understand the role of the FEF, we reversibly inactivated a portion of it while a monkey made saccades and fixations in response to visual stimuli. Lidocaine was infused into a FEF and neural inactivation was monitored with a nearby microelectrode. We used two saccadic tasks. In the delay task, a target was presented and then extinguished, but the monkey was not allowed to make a saccade to its location until a cue to move was given. In the step task, the monkey was allowed to look at a target as soon as it appeared. During FEF inactivation, monkeys were severely impaired at making saccades to locations of extinguished contralateral targets in the delay task. They were similarly impaired at making saccades to locations of contralateral targets in the step task if the target was flashed for < or =100 ms, such that it was gone before the saccade was initiated. Deficits included increases in saccadic latency, increases in saccadic error, and increases in the frequency of trials in which a saccade was not made. We varied the initial fixation location and found that the impairment specifically affected contraversive saccades rather than affecting all saccades made into head-centered contralateral space. Monkeys were impaired only slightly at making saccades to contralateral targets in the step task if the target duration was 1000 ms, such that the target was present during the saccade: latency increased, but increases in saccadic error were mild and increases in the frequency of trials in which a saccade was not made were insignificant. During FEF inactivation there usually was a direct correlation between the latency and the error of saccades made in response to contralateral targets. In the delay task, FEF inactivation increased the frequency of making premature saccades to ipsilateral targets. FEF inactivation had inconsistent and mild effects on saccadic peak velocity. FEF inactivation caused impairments in the ability to fixate lights steadily in contralateral space. FEF inactivation always caused an ipsiversive deviation of the eyes in darkness. In summary, our results suggest that the FEF plays major roles in (1) generating contraversive saccades to locations of extinguished or flashed targets, (2) maintaining contralateral fixations, and (3) suppressing inappropriate ipsiversive saccades.

A Video Game-Integrated Electromyography Biofeedback Device for Use in Physical Therapy

We present a novel system to be used in the rehabilitation of patients with forearm injuries. The system uses surface electromyography (sEMG) recordings from a wireless sleeve to control video games designed to provide engaging biofeedback to the user. An integrated hardware/software system uses a neural net to classify the signals from a user’s muscles as they perform one of a number of common forearm physical therapy exercises. These classifications are used as input for a suite of video games that have been custom-designed to hold the patient’s attention and decrease the risk of noncompliance with the physical therapy regimen necessary to regain full function in the injured limb. The data is transmitted wirelessly from the on-sleeve board to a laptop computer using a custom-designed signal-processing algorithm that filters and compresses the data prior to transmission. We believe that this system has the potential to significantly improve the patient experience and efficacy of physical therapy using biofeedback that leverages the compelling nature of video games.

Muscle activation patterns in shoulder impingement patients

Introduction: Shoulder impingement is one of the most common presentations of shoulder joint problems 1. It appears to be caused by a reduction in the sub-acromial space as the humerus abducts between 60o -120o – the 'painful arc'. Structures between the humeral head and the acromion are thus pinched causing pain and further pathology 2. Shoulder muscle activity can influence this joint space but it is unclear whether this is a cause or effect in impingement patients. This study aimed to observe muscle activation patterns in normal and impingement shoulder patients and determine if there were any significant differences. Method: 19 adult subjects were asked to perform shoulder abduction in their symptomatic arm and non-symptomatic. 10 of these subjects (age 47.9 ± 11.2) were screened for shoulder impingement, and 9 subjects (age 38.9 ± 14.3) had no history of shoulder pathology. Surface EMG was used to collect data for 6 shoulder muscles (Upper, middle and lower trapezius, serratus anterior, infraspinatus, middle deltoids) which was then filtered and fully rectified. Subjects performed 3 smooth unilateral abduction movements at a cadence of 16 beats of a metronome set at 60bpm, and the mean of their results was recorded. T-tests were used to indicate any statistical significance in the data sets. Significance was set at P<0.05. Results: There was a significant difference in muscle activation with serratus anterior in particular showing a very low level of activation throughout the range when compared to normal shoulder activation patterns (<30%). Middle deltoid recruitment was significantly reduced between 60-90o in the impingement group (30:58%).Trends were noted in other muscles with upper trapezius and infraspinatus activating more rapidly and erratically (63:25%; 60:27% respectively), and lower trapezius with less recruitment (13:30%) in the patient group, although these did not quite reach significance. Conclusion: There appears to be some interesting alterations in muscle recruitment patterns in impingement shoulder patients when compared against their own unaffected shoulders and the control group. In particular changes in scapula control (serratus anterior and trapezius) and lateral rotation (infraspinatus), which have direct influence on the sub-acromial space, should be noted. It is still not clear whether these alterations are causative or reactionary, but this finding gives a clear indication to the importance of addressing muscle reeducation as part of a rehabilitation programme in shoulder impingement patients.

The influence of crank configuration on muscle activity and torque production during arm crank ergometry

This study investigated the effect of crank configuration on muscle activity and torque production during submaximal arm crank ergometry. Thirteen non-specifically trained male participants volunteered. During the research trials they completed a warm-up at 15 W before two 3-min exercise stages were completed at 50 and 100 W; subjects used either a synchronous or asynchronous pattern of cranking. During the final 30-s of each submaximal exercise stage electromyographic and torque production data were collected. After the data had been processed each parameter was analysed using separate 2-way ANOVA tests with repeated measures. The activity of all muscles increased in line with external workload, although a shift in the temporal pattern of muscle activity was noted between crank configurations. Patterns of torque production during asynchronous and synchronous cranking were distinct. Furthermore, peak, minimum and delta (peak-minimum) torque values were different (P < 0.05) between crank configurations at both workloads. For example, at 100 W, peak torque using synchronous [19.6 (4.3) Nm] cranking was higher (P < 0.05) compared to asynchronous [16.8 (1.6) Nm] cranking. In contrast minimum torque was lower (P < 0.05) at 100 W using synchronous [4.8 (1.7) Nm] compared to asynchronous [7.3 (1.2) Nm] cranking. There was a distinct bilateral asymmetry in torque production during asynchronous cranking with the dominant transmitting significantly more force to the crank arm. Taken together, these preliminary data demonstrate the complex nature of muscle activity during arm crank ergometry performed with an asynchronous or synchronous crank set-up. Further work is required to determine how muscle activity (EMG activity) and associated patterns of torque production influence physiological responses and functional capacity during arm crank ergometry.

Kinematics and EMG analysis of expert pole vaulter's lower limb during take off phase (P218)

Introduction: The critical phase, in jumping events in track and field, appears to be between touchdown and take-off. Since obvious similarities exist between the take off phase in both long jump and pole vault, numerous 3D kinematics and electromyographic studies have only looked at long jump. Currently there are few detailed kinematics electromyographic data on the pole vault take-off phase. The aim of this study was therefore to characterise kinematics and electromyographic variables during the take-off phase to provide a better understanding of this phase in pole vaulting and its role in performance outcome. Material and methods: Six pole-vaulters took part in the study. Kinematics data were captured with retro reflective markers fixed on the body. Hip, knee and ankle angle were calculated. Differential bipolar surface electrodes were placed on the following muscles of the take-off leg: tibialis anterior, lateral gastrocnemius, vastus lateralis, rectus femoris, bicep femoris and gluteus maximus. EMG activity was synchronously acquired with the kinematic data. EMG data were rectified and smoothed using a second order low pass Butterworth Bidirectional filter (resulting in a 4th order filter) with a cut-off frequency of 14 Hz. Results: Evolution of hip, knee and ankle angle show no significant differences during the last step before touchdown, the take-off phase and the beginning of fly phase. Meanwhile, strong differences in EMG signal are noted inter and intra pole vaulter. However for a same subject the EMG activities seem to converge to some phase locked point. Discussion: All pole vaulters have approximately the same visible coordination This coordination reflects a different muscular control among pole vaulters but also for a considered pole vaulter. These phase locked point could be considered as invariant of motor control i.e. a prerequisite for a normal sequence of the movement and performance realization.

Microsporidia-nematode associations in methane seeps reveal basal fungal parasitism in the deep sea

The deep sea is Earth’s largest habitat but little is known about the nature of deep-sea parasitism. In contrast to a few characterized cases of bacterial and protistan parasites, the existence and biological significance of deep-sea parasitic fungi is yet to be understood. Here we report the discovery of a fungus-related parasitic microsporidium, Nematocenator marisprofundi n. gen. n. sp. that infects benthic nematodes at Pacific Ocean methane seeps on the Pacific Ocean floor. This infection is species-specific and has been temporally and spatially stable over two years of sampling, indicating an ecologically consistent host-parasite interaction. A high distribution of spores in the reproductive tracts of infected males and females and their absence from host nematodes’ intestines suggests a sexual transmission strategy in contrast to the fecal-oral transmission of most microsporidia. N. marisprofundi targets the host’s body wall muscles causing cell lysis, and in severe infection even muscle filament degradation. Phylogenetic analyses placed N. marisprofundi in a novel and basal clade not closely related to any described microsporidia clade, suggesting either that microsporidia-nematode parasitism occurred early in microsporidia evolution or that host specialization occurred late in an ancient deep-sea microsporidian lineage. Our findings reveal that methane seeps support complex ecosystems involving interkingdom interactions between bacteria, nematodes, and parasitic fungi and that microsporidia parasitism exists also in the deep sea biosphere.

Variaciones termométricas en la planta del pie y piernas valorada en corredores antes y después de correr 30 km

La termometría es una técnica no invasiva que permite cuantificar los cambios en la temperatura cutánea y evaluarla de forma cuantitativa. El aumento significativo de la temperatura puede indicar la existencia de patología. Se ha demostrado que la actividad muscular induce procesos de transferencia de calor entre los músculos y las capas superficiales de tejido. En este estudio queremos cuantificar los cambios de temperatura que se producen en los músculos del pie y miembro inferior tras una carrera de 30 km, para ello hemos utilizado una cámara termográfica de alta resolución. Contamos con la colaboración voluntaria de 32 sujetos sanos a los que procedimos a tomar fotografías de la planta del pie, parte anterior de la pierna, parte posterior de la pierna, parte anterior del muslo y parte posterior del muslo en dos etapas, primero antes de la carrera y segunda toma después de la carrera de 30 km, de esta manera pudimos valorar si había o no variación de temperatura en las zonas seleccionadas. Tras el análisis de los datos obtenidos encontramos significativas variaciones térmicas en Talón, cabeza primer metatarsiano, cabeza segundo metatarsiano, cabeza tercer metatarsiano, cabeza cuarto metatarsiano, cabeza quinto metatarsiano, apófisis estiloides quinto metatarsiano, arco longitudinal interno, maléolo interno, maléolo externo, peroneo lateral largo, vasto interno, vasto externo, recto femoral, tensor de la fascia lata, inserción cuádriceps, gemelo interno, tendón de Aquiles y Biceps femoral.

Conservative Interventions for mobile Pes Planus in Adults: a systematic review

Antecedentes. Pes Adulto planus (pie plano) es un problema común encontrado por muchos profesionales de la salud. A pesar de la percepción de que el pie plano puede causar dolor y deteriorar su función, la disponibilidad y el uso generalizado de diversos tratamientos, no hay consenso sobre la estrategia óptima de tratamiento. Objetivo. Evaluar la efectividad de las intervenciones conservadoras (no quirúrgicos) para pie plano en los adultos. Método. Se realizó una búsqueda sistemática de la literatura. Esto incluye: el Registro Cochrane Central de Ensayos Controlados; los Juicios CMSG Especializados Registro; una búsqueda electrónica se realizó utilizando MEDLINE (1960 a junio de 2012), EMBASE (1980 a junio de 2012), y CINAHL (1982 - junio de 2012). Revistas especializadas, listas de referencias de ensayos y artículos de revisión se realizaron búsquedas manuales. Criterios de selección: Ensayos aleatorios o cuasialeatorios de intervenciones de tratamiento para el pie plano en los adultos. Se excluyeron los ensayos que incluyeron patologías específicas como el dolor plantar del talón, las fracturas por sobrecarga de los metatarsianos, disfunción del tendón tibial posterior-, fracturas de tobillo, patologías del pie reumatoide, enfermedades neuromusculares y las complicaciones del pie diabético. Recopilación y análisis de datos: Dos autores seleccionaron de forma independiente los resultados de la búsqueda para identificar a aquellos que satisfacen los criterios de inclusión y evaluaron la calidad de los incluidos mediante una lista de control basado en la Evaluación de la Colaboración Cochrane de Riesgo. Esta herramienta se centró en el riesgo de la selección, el rendimiento, la detección, la heterogeneidad y el sesgo de notificación. Resultados. Cuatro ensayos, con 140 sujetos, cumplieron los criterios de inclusión para la revisión. Los cuatro fueron juzgados como de alto riesgo de sesgo en al menos un área, y también estaban en riesgo de sesgo incierto en al menos otra zona. Todos anotaron altamente en relación al sesgo de deserción, debido al corto seguimiento tiempos y diseños experimentales utilizados. Los datos no se agruparon debido al alto nivel de heterogeneidad identificada en las intervenciones evaluadas, los participantes seleccionados y medir los resultados. Los resultados de un estudio sugieren que después de cuatro semanas de uso ortesis puede resultar en una mejora significativa en vaivén lateral medio, y pueden resultar en una mejor, aunque no significativa, en general relacionados con la calidad de vida de los pies (Roma 2004). Un estudio (Redmond 2009) sugiere que su efecto sobre la distribución de la presión plantar en el pie puede no depender de si son personalizados o dispositivos prefabricados. Aunque este estudio se identificaron cambios significativos en algunas variables de presión plantar tanto con la costumbre y dispositivos prefabricados, otro (Esterman 2005) no encontró ningún efecto significativo de longitud ¾ ortesis prefabricadas sobre el dolor, la incidencia de lesiones, salud pie o de calidad de vida en un grupo de reclutas de la fuerza aérea. El cuarto estudio (Jung 2009) sugiere que el ejercicio de los músculos intrínsecos del pie puede mejorar el efecto de las ortesis. A pesar de estos resultados, ya que cada estudio incurrió riesgo de sesgo en al menos un área no se pueden sacar conclusiones

Second Metatarsophalangeal joint Synovitis: Update

In podiatric clinics is very common to find inflamatory process in metatarsophalangeal joint capsule , plantar plate and collateral ligaments damage, but it is not clearly recognized. Many authors hipotetized with joint instability of multiple aetiology and his concomitant evolution in different stages with own joint disease. This pathology has more incidence in second metatarsophalangeal joint than third and others and it is a common etiology of metatarsal pain. Bad biomechanics alters forefoot function and can produce overload in capsular joint, decreasing mobility and getting worse the pathology.

Hand arthritis in systemic lupus erythematosus: an ultrasound pictorial essay.

A small minority of systemic lupus erythematosus (SLE) patients may develop a deforming arthritis, typically with a non-erosive (Jaccoud's) pattern, although erosive features indistinguishable from rheumatoid arthritis may also occur. High-resolution ultrasonography (HRUS) allows detailed 'real time' imaging of joint and tendon morphostructural changes involving the hand in patients with several rheumatic diseases. The main aim of this pictorial essay is to provide the first descriptive HRUS and power Doppler (PD) findings of joint and tendon involvement of the hand and wrist in patients with SLE arthritis. Seventeen patients with SLE and hand involvement were examined. HRUS of the wrist, 2nd and 3rd MCP joints, 3rd PIP joint and 2nd, 3rd and 4th finger flexor tendons were studied in the dominant hand for each patient. Sixteen (94%) patients had joint effusion or synovial hypertrophy in the wrist. Twelve (71%) patients had joint effusion or synovial hypertrophy in 2nd or 3rd MCPJs. Eight (47%) patients had erosion at 2nd or 3rd MCPJs. In three cases erosions were not present radiologically. Eleven (65%) patients had evidence of tenosynovitis. In SLE, HRUS with PD detects a high prevalence of inflammatory pathology in the tendons and synovium of the hand and wrist, and a high prevalence of MCP joint erosions. HRUS offers a sensitive, real-time and readily repeatable assessment of soft-tissue, inflammatory and bony changes in SLE hands.

Mechanisms of Disease: specialized interstitial cells of the urinary tract--an assessment of current knowledge.

Scientists interested in the smooth muscles of the urinary tract, and their control, have recently been studying cells in the interstitium of tissues that express the c-kit antigen (Kit(+) cells). These cells have morphologic features that are reminiscent of the well-described pacemaker cells in the gut, the interstitial cells of Cajal (ICC). The spontaneous contractile behavior of muscles in the urinary tract varies widely, and it is clear that urinary tract Kit(+) interstitial cells cannot be playing an identical role to that played by the ICC in the gut. Nevertheless, there is increasing evidence that they do play a role in modulating the contractile behavior of adjacent smooth muscle, and might also be involved in mediating neural control. This review outlines the properties of ICC in the gut, and gives an account of the discovery of cells in the interstitium of the main components of the urinary tract. The physiologic properties of such cells and the functional implications of their presence are discussed, with particular reference to the bladder. In this organ, Kit(+) cells are found under the lamina propria, where they might interact with the urothelium and with sensory nerves, and also between and within the smooth-muscle bundles. Confocal microscopy and calcium imaging are being used to assess the physiology of ICC and their interactions with smooth muscles. Differences in the numbers of ICC are seen in smooth muscle specimens obtained from patients with various pathologies; in particular, bladder overactivity is associated with increased numbers of these cells.

Electrical activity induced by nitric oxide in canine colonic circular muscle.

Nitric oxide generates slow electrical oscillations (SEOs) in cells near the myenteric edge of the circular muscle layer, which resemble slow waves generated by interstitial cells of Cajal (ICCs) at the submucosal edge of this muscle. The properties of SEOs were studied to determine whether these events are similar to slow waves. Rapid frequency membrane potential oscillations (MPOs; 16 +/- 1 cycles/min and 9.6 +/- 0.2 mV) were recorded from control muscles near the myenteric edge. Sodium nitroprusside (0.3 microM) reduced MPOs and initiated SEOs (1.3 +/- 0.3 cycles/min and 13.4 +/- 1.4 mV amplitude). SEOs were abolished by the guanylate cyclase inhibitor 1H-[1,2,4]-oxadiazolo-[4,3-a]-quinoxaline-1-one (10 microM). MPOs were abolished by nifedipine (1 microM), whereas SEO frequency increased and the amount of depolarization decreased. BAY K 8644 (1 microM) prolonged SEOs and reduced their frequency. SEOs were abolished by Ni(2+) (0.5 mM), low Ca(2+) solution (0.1 mM Ca(2+)), cyclopiazonic acid (10 microM), and the mitochondrial uncouplers antimycin (10 microM) and carbonyl cyanide p-trifluoromethoxyphenylhydrazone (1 microM). Oligomycin (10 microM) was without effect. These effects are similar to those described for colonic slow waves. Our results suggest that nitric oxide-induced SEOs are similar in mechanism to slow waves, an activity not previously thought to be generated by myenteric pacemakers.

Role of calcium influx through voltage-operated calcium channels and of calcium mobilization in the physiology of Schistosoma mansoni muscle contractions

We tested the hypothesis that voltage-operated Ca2+ channels mediate an extracellular Ca2+ influx in muscle fibres from the human parasite Schistosoma mansoni and, along with Ca2+ mobilization from the sarcoplasmic reticulum, contribute to Muscle contraction. Indeed, whole-cell voltage clamp revealed voltage-gated inward currents carried by divalent ions with a peak current elicited by steps to + 20 mV (from a holding potential of -70 mV). Depolarization of the fibres by elevated extracellular K+ elicited contractions that were completely dependent on extracellular Ca2+ and inhibited by nicardipine (half inhibition at 4(.)1 mu M). However these contractions were not very sensitive to other classical blockers of voltage-gated Ca2+ channels, indicating that the schistosome Muscle channels have an atypical pharmacology when compared to their mammalian counterparts. Furthermore, the contraction induced by 5 mM caffeine was inhibited after depletion of the sarcoplasmic reticulum either with thapsigargin (10 mu M) or ryanodine (10 mu M). These data suggest that voltage-operated Ca2+ channels docontribute to S. mansoni contraction as does the mobilization of stored Ca2+, despite the small volume of sarcoplasmic reticulum in schistosome smooth muscles.

Flatworm nerve-muscle: structural and functional analysis

Platyhelminthes occupy a unique position in nerve-muscle evolution, being the most primitive of metazoan phyla. Essentially, their nervous system consists of an archaic brain and associated pairs of longitudinal nerve cords cross-linked as an orthogon by transverse commissures. Confocal imaging reveals that these central nervous system elements are in continuity with an array of peripheral nerve plexuses which innervate a well-differentiated grid work of somatic muscle as well as a complexity of myofibres associated with organs of attachment, feeding, and reproduction. Electrophysiological studies of flatworm muscles have exposed a diversity of voltage-activated ion channels that influence muscle contractile events. Neuronal cell types are mainly multi- and bi-polar and highly secretory in nature, producing a heterogeneity of vesicular inclusions whose contents have been identified cytochemically to include all three major types of cholinergic, aminergic, and peptidergic messenger molecules. A landmark discovery in flatworm neurobiology was the biochemical isolation and amino acid sequencing of two groups of native neuropeptides: neuropeptide F and FMRFamide-related peptides (FaRPs). Both families of neuropeptide are abundant and broadly distributed in platyhelminths, occurring in neuronal vesicles in representatives of all major flatworm taxa. Dual localization studies have revealed that peptidergic and cholinergic substances occupy neuronal sets separate from those of serotoninergic components. The physiological actions of neuronal messengers in flatworms are beginning to be established, and where examined, FaRPs and 5-HT are myoexcitatory, while cholinomimetic substances are generally inhibitory. There is immunocytochemical evidence that FaRPs and 5-HT have a regulatory role in the mechanism of egg assembly. Use of muscle strips and (or) muscle fibres from free-living and parasitic flatworms has provided baseline information to indicate that muscle responses to FaRPs are mediated by a G-protein-coupled receptor, and that the signal transduction pathway for contraction involves the second messengers cAMP and protein kinase C.

Molecular characterization of Nosema bombi (Microsporidia : Nosematidae) and a note on its sites of infection in Bombus terrestris (Hymenoptera : Apoidea)

Investigations of queen, worker and male bumble bees (Bombus terrestris) showed that all individuals became infected with Nosema bombi. Infections were found in Malpighian tubules, thorax muscles, fat body tissue and nerve tissue, including the brain. Ultrastructural studies revealed thin walled emptied spores in host cell cytoplasm interpreted as autoinfective spores, besides normal spores (environmental spores) intended for parasite transmission between hosts. The nucleotide sequence of the gene coding for the small subunit rRNA (SSU-rRNA) from Microsporidia isolated from B. terrestris, B. lucorum, and B. hortorum were identical, providing evidence that N. bombi infects multiple hosts. The sequence presented here (GenBank Accession no AY008373) is different from an earlier submission to GenBank (Accession no U26158) of a partial sequence of the same gene based on material collected from B. terrestris. It still remains to be investigated if there is species diversity among Microsporidia found in bumble bees.