Dacron fabric-enveloped hydroxyapatite prosthesis for sternal tumor defect: an autopsy report

A 38-year-old housewife with solitary plasmacytoma of the manubrium who underwent a subtotal sternectomy treated by resection of the lesion is reported. This was followed by replacement with a Dacron fabric-enveloped hydroxyapatite prosthesis. The Dacron fabric was sutured to the surrounding tissues, and then the clavicle was passed through the cylindrical-shaped Dacron fabric to form a sternoclavicular joint capsule. The patient returned to her daily life 3 months after the operation. She had no trouble in her daily living, without any dislocation of the sternoclavicular joints or any displacement of the artificial sternum. The autopsy examination about 1 year after the operation showed that the Dacron fabric enveloping the artificial sternum became stronger with time. The sternoclavicular joint also was stably fixed, and the Dacron fabric fulfilled its function as an artificial articular capsule and biologic fixation of the surrounding supporting tissues.     

The effect of tactile and verbal guidance during scapulothoracic exercises: An EMG and kinematic investigation

BackgroundClinician-led training through tactile and verbal guidance to improve muscle activity and joint motion are a common but understudied focus of therapeutic interventions for shoulder pain. The purpose of this study was to determine if clinician guidance changes scapulothoracic muscle activity and kinematics compared to unguided shoulder exercises.MethodsEleven participants with shoulder pain were studied. Electromyographic (EMG) sensors were placed on the serratus anterior and upper and lower trapezii. Scapulothoracic and sternoclavicular kinematics were collected using electromagnetic sensors. Five common resisted shoulder exercises were performed with the following guidance: unguided, combined (verbal and tactile cues), and verbal guidance only. One-way repeated measures ANOVAs determined the effect of guidance versus unguided conditions for each exercise.ResultsNine of ten combinations of exercise and guidance techniques demonstrated a significant effect of guidance for either muscle activity or joint kinematics. The guidance condition with the most frequent significant improvements across all variables was the combined condition. The exercises with the most frequent significant improvements across all variables were the external rotation exercises. Variables improved most frequently were: upper:lower trapezius EMG ratio (up to 11%), sternoclavicular elevation (up to 6°) and scapulothoracic internal rotation positioning (up to 8°), and sternoclavicular retraction displacement (up to 5°).ConclusionShoulder muscle activity and kinematics during exercises can be modified by tactile and verbal guidance. Most improvements in muscle activity occurred with verbal guidance during external rotation exercises. Most improvements in joint positioning and movement occurred with combined guidance during external rotation exercises.     

Individual variability of the projection line of the common carotid artery

The investigation has been performed on 87 corpses of persons of both sex, that died after 60 years of age from the pathology not connected with any diseases in the neck organs. Individual variability in the common carotid artery projection line has been revealed; it conforms, to a certain extent, with the value of the neck index. When the neck is short and thick, the artery position corresponds to the line that runs across the following points: the superior--0.5 cm forward from the mandibular angle, the inferior--0.5 cm medially from the sternoclavicular joint. When the neck index is within the limits 1.71-1.88, it is expedient to draw the classical projection line. When the neck index is within the limits 1.57-1.69, it is possible to determine the projection zone as an elongated rectangle. At the bottom of every side the border of this zone is a straight line drawn between the sternoclavicular joint and the point situating 0.6 cm laterally from the joint, and at the top--the line connecting the top of the mastoid process with the point 1.0 cm behind the mandibular angle.     

Use of cyclodextrin for AFM monitoring of model raft formation

The lipid rafts membrane microdomains, enriched in sphingolipids and cholesterol, are implicated in numerous functions of biological membranes. Using atomic force microscopy, we have examined the effects of cholesterol-loaded methyl-beta-cyclodextrin (MbetaCD-Chl) addition to liquid disordered (l(d))-gel phase separated dioleoylphosphatidylcholine (DOPC)/sphingomyelin (SM) and 1-palmitoyl-2-oleoyl phosphatidylcholine (POPC)/SM supported bilayers. We observed that incubation with MbetaCD-Chl led to the disappearance of domains with the formation of a homogeneously flat bilayer, most likely in the liquid-ordered (l(o)) state. However, intermediate stages differed with the passage through the coexistence of l(o)-l(d) phases for DOPC/SM samples and of l(o)-gel phases for POPC/SM bilayers. Thus, gel phase SM domains surrounded by a l(o) matrix rich in cholesterol and POPC could be observed just before reaching the uniform l(o) state. This suggests that raft formation in biological membranes could occur not only via liquid-liquid but also via gel-liquid immiscibility. The data also demonstrate that MbetaCD-Chl as well as the unloaded cyclodextrin MbetaCD make holes and preferentially extract SM in supported bilayers. This strongly suggests that interpretation of MbetaCD and MbetaCD-Chl effects on cell membranes only in terms of cholesterol movements have to be treated with caution.     

The cortical effect of chewing gum during hand movements: A functional MRI study

Abstract

Nine right-handed normal subjects were recruited for this study. We compared the cortical activation during execution of hand movements (right finger flexion–extension) with that during execution of hand movements while chewing gum (right side chewing). We found that execution of hand movements while chewing gum induced less activation in the contralateral SM1 than hand movements alone. Based on our findings, it appears chewing gum during execution of hand movements enhanced the efficiency of hand movements.     

Positive work as a function of eccentric load in maximal leg extension movements

Negative and positive work performed during leg extension movements of 53 well trained subjects was measured with the help of a special dynamometer. The subjects performed four maximal push off trials against five different loads (25-105 kg): two two-legged extensions from a squatting position (SM) with a knee angle of 70 degrees and two trials with a preliminary counter movement (CM) but with the same extension range as in the SM. Positive work differed only by about 4% between CM and SM in spite of large differences in initial forces at the onset of concentric contraction. Based on simulations, it is suggested that in CM the advantage of stored elastic energy can almost completely be nullified by the disadvantage of a limited shortening distance of the contractile elements. It is hypothesised that elastic energy in CM can only cause considerable extra work during concentric contraction compared to the maximal positive work done in SM if the total range of lengthening and shortening of the muscle(s) involved is larger in CM than in SM.     

Sternoclavicular Bacterial Arthritis

Bacterial infection of the sternoclavicular joint is an unusual event, with cases being reported in those with diabetes mellitus, in intravenous drug abusers, and in patients afflicted with rheumatoid arthritis. A case of this unique infection occurred in a person not known to be at risk for septic arthritis. Our report shows the difficulty in diagnosing this disorder.     

Form and function in lacertilian knee and mesotarsal joints; a contribution to the analysis of sprawling locomotion

The structure and function of the knee and mesotarsal (ankle) joints in lizards with normally developed limbs is described. It is shown that the knee joint is strictly of the hinge type, but is asymmetrical, resulting in a mesial inflexion of the long axis of the crus relative to that of the femur. The mesotarsal joint is a complex screw joint which permits conjunct rotatory movements of the crus on the pes, as well as flexion-extension. These movements are mediated by interlocking control surfaces on either side of the joint, and are an external expression of the geometry of these surfaces. The morphology of these joints, and the movements they permit are evaluated with reference to the movements of the limb segments during retraction.     

The impact of adding trunk motion to the interpretation of the role of joint moments during normal walking

Biomechanical model assumptions affect the interpretation of the role of the muscle or joint moments to the segmental power estimated by induced acceleration analysis (IAA). We evaluated the effect of modeling the pelvis and trunk segments as two separate segments (8 SM) versus as a single segment (7 SM) on the segmental power, support of the body, knee and hip extension acceleration produced by the joint moments during the stance phase of normal walking. Significant differences were observed in the contribution of the stance hip abductor and extensor moments to support, ipsilateral knee and hip acceleration, and ipsilateral thigh and upper body power. The primary finding was that the role of the stance hip moment in generating ipsilateral thigh and upper body power differed based on degrees of freedom in the model. Secondarily, the magnitude of contributions also differed. For example, the hip abductor and extensor moments showed greater contribution to support, hip and knee acceleration in the 8 SM. IAA and segment power analysis are sensitive to the degrees of freedom between the pelvis and trunk. There is currently no gold standard by which to evaluate the accuracy of IAA predictions. However, modeling the pelvis and trunk as separate segments is closer to the anatomical architecture of the body. An 8 SM appears to be more appropriate for estimating the role of joint moments, particularly to motion of more proximal segments during normal walking.     

Sensory influences on the coordination of two leg joints during searching movements of stick insects

Animals (Cuniculina impigra) possessing only one foreleg with restrained coxa perform very stereotyped searching movements during which the movements of the femur-tibia and coxa-trochanter joints are well coordinated. After ablation of either hairfield BF1 (measuring the position of the coxa-trochanter joint) or the apodeme of the femoral chordotonal organ (measuring the position of the femur-tibia joint) each joint can still be moved but the coordination changes and becomes very labile. The consequences for the ideas about the construction principles of the pattern generator for searching movements are discussed.     

Postsynaptic potentials in cat abducens motoneurons evoked by stimulation of cortical eye fields.

Intracellular recordings were carried out on abducens motoneurons of encephale isole cats in order to analyse synaptic influences of cortical areas engaged in control of saccadic eye movements. It was found that, in addition to the "frontal eye field" (FEF), eye movements containing a contraversive component may be triggered by electrical stimulation of the 1st and the 2nd sensorimotor areas (SM). Correspondingly, sustained postsynaptic responses (EPSPs) and rhythmic firing of abducens motoneurons could be reliably induced by prolonged stimulus trains. In this respect, the efficiencies of FEF and SM were about the same. They appeared to be higher than the efficiency of excitatory pyramidal actions on spinal motoneurons as reported by others. EPSPs elicited from both regions by short stimuli were, on the major part, polysynaptic. Quite complex multineuronal chains appeared to be stronger engaged in the transmission of FEF effects. EPSPs of SM origin contained a disynaptic fraction which could not be reliably identified in FEF responses. Recipocal innervation of abducens nuclei on both sides was found to be reflected in the asymmetry of excitatory and inhibitory influences from two hemispheres: EPSPs predominated in responses to contralateral, IPSPs and mixed PSPs - to ipsilateral stimulation.     

Is lower limb muscle synchrony during landing affected by gender? Implications for variations in ACL injury rates.

This study examined whether lower limb muscle synchrony during abrupt landings was affected by gender, thereby predisposing females to a higher incidence of non-contact anterior cruciate ligament (ACL) injuries than males. Seven males and 11 females landed in single-limb stance on a force platform after receiving a chest-height netball pass and decelerating abruptly. Ground reaction force and electromyographic data for rectus femoris, vastus lateralis, vastus medialis, semimembranosus (SM), biceps femoris, and gastrocnemius were sampled (1000 Hz) during landing. Subjects' sagittal plane motion was also filmed (200 Hz). Knee joint reaction forces and sagittal planar net moments of force were estimated using Newtonian equations of motion and inverse dynamics. Tibiofemoral shear forces (F(s)) were obtained and muscle bursts temporally analysed with respect to initial foot-ground contact (IC) and peak F(s) times. Males displayed significantly delayed SM onset relative to IC (113+/-46 ms) compared to females (173+/-54 ms; p=0.03), and significantly delayed SM peak activity relative to peak F(s) (54+/-27 ms) compared to females (77+/-15 ms; p=0.03). Delayed SM activity during landing was suggested to allow peak muscle activity to better coincide with high anterior F(s), thereby acting as an ACL synergist via increased joint compression and posterior tibial drawer. It was concluded that females displayed muscle synchrony less protective of the ACL than males, possibly increasing their susceptibility to non-contact ACL injuries.     

Hot-water spraying is a sensitive test for signs of life before dressing and scalding in pig abattoirs with carbon dioxide (CO2) stunning

This study investigated the benefits of hot-water spraying (HWS) as a diagnostic test to verify the absence of signs of life (SOL) before scalding in pigs slaughtered with carbon dioxide (CO₂) stunning. A total of 37 108 finishing pigs from five German abattoirs (A to E) operating at 55 to 571 pigs per hour were assessed. Suspended pigs were sprayed onto the muzzle, head and front legs (143 to 258 s post sticking for 4 to 10 s, 57°C to 72°C). Any active movements during HWS were rated as positive test outcomes. In comparison, SOL were considered to be absent if a subsequent manual examination was negative and no active movements were observed following HWS. The incidence of pigs with activity during hot-water spraying (PWA) was restricted to two abattoirs (B: 0.25%; D: 0.02%; A, C, E: 0.00%). PWA showed movements of facial muscles (88%), mouth opening (78%), righting reflex (63%), isolated leg movements (35%) and vocalization (4%). The manual examination was positive in 71% of PWA (corneal/dazzle reflex: 67%/53%, nasal septum pinch: 33%), whereas all inactive pigs tested negative (P<0.001). The sensitivity for HWS as a test for SOL was calculated as 100%, dropping to 75% when only obvious and strong movements were taken into account. The specificity was >99.9% in either case. Any positive manual findings as well as any respiratory activity were instantly terminated using a penetrating captive bolt. Active movements triggered by the shot were shown to be an indicator for SOL (P<0.001). Video analyses revealed that spontaneous movements (SM) following sticking were present in 100% of PWA as opposed to 3.1% in pigs without such activity (controls). Results for different categories of SM in PWA v. controls were as follows: 100% v. 2.6% for mouth opening, 16.0% v. 0.1% for righting reflex and 22.0% v. 0.9% for isolated leg movements (all P<0.001). First mouth opening after sticking was observed later in PWA (28±24 v. 10±7 s), but mouth openings were observed for a longer period of time (141±44 v. 27±25 s) (both P<0.001). PWA with shorter mouth-opening intervals showed higher movement intensities during HWS and more positive manual findings (P<0.05). We conclude that HWS is a promising test for SOL. SM and sustained mouth opening in particular are indicators for compromised animal welfare and affected pigs should be shot by captive bolt.     

Identification of intra-group,inter-individual,and gene-specific variances in mRNA expression profiles in the rheumatoid arthritis synovial membrane

Introduction  

Rheumatoid arthritis (RA) is a chronic inflammatory and destructive joint disease characterized by overexpression of pro-inflammatory/pro-destructive genes and other activating genes (for example, proto-oncogenes) in the synovial membrane (SM). The gene expression in disease is often characterized by significant inter-individual variances via specific synchronization/desynchronization of gene expression. To elucidate the contribution of the variance to the pathogenesis of disease, expression variances were tested in SM samples of RA patients, osteoarthritis (OA) patients, and normal controls (NCs).     

A model of control of the movement of the multiarticular extremity

A model for coordinated execution of multijoint goal-directed limb movements is suggested from the following principles. (1) Central control signals for a single limb joint are individually formed, proceeding from its ability to bring the limb nearer to the target and leaving control signals directed simultaneously to other joint out of account. The joints thereby behave as a set of Tsetlin's abstract automata [11], each functioning independently and guided by a common, collective effect. (2) Neither levels of muscle activation, nor force and kinematic variables are directly specified by the command signals. They only modify the system's parameters that affect equilibrium joint positions, and thus make the limb to move to the goal. A concrete model based on the above principles is described and its behavior is compared with actual goal-directed movements in man and spinal frogs. Various control strategies for multiarticular movements in living organisms are discussed.     

Motion analysis of leg joints associated with escape turns of the cockroach,Periplaneta americana

Considerable information is now available on the neural organization of the escape system of the American cockroach. To relate these data to the behavior, we need detailed information on the movements made at the principle leg joints that produce the turn. We used motion analysis of high speed video records to acquire such information. Records from both free ranging and tethered animals were analyzed. 1. We analyzed individual joint movements using a tethered preparation. Stimuli from 4 different angles around the animal were used. For all wind angles, the femur-tibia (FT) joint on the mesothoracic leg that is ipsilateral to the wind source extended while the contralateral mesothoracic FT joint flexed. This moved both of these legs laterally toward the wind source. In freely moving animals the FT movements provide forces that turn the animal away from the wind source. 2. The ipsilateral mesothoracic coxa-femur (CF) joint extended for all wind angles. The contralateral mesothoracic CF joint extended in response to most winds from the rear, but switched to flexion in response to wind from the side and front. As a result of these joint movements, rear wind resulted in rearward movements of the contralateral mesothoracic leg, while side and front wind resulted in more forward movements of that leg. 3. The CF and FT joints for both ipsilateral and contralateral metathoracic legs extended to wind from the rear and switched to flexion as the wind was placed at more anterior positions around the animal. In freely moving animals, extension of these joints would push the animal forward. Flexion would pull the animal backward. 4. Several of the joints showed correlations between rate of movement and initial joint angle. That is, joints that were already flexed at the onset of stimulation tended to move at a faster rate to a final position than joints that started at a more extended position. 5. Metathoracic FT and CF joints showed a high degree of positive correlation during the escape movements. Indeed, many curves showing movement of metathoracic FT and CF joints with time were virtually identical.     

The investigation of locomotor activity control system in humans under the air-stepping conditions during passive and voluntary leg movements

The degree of activation of the central stepping program during passive leg movement was studied in healthy subjects under unloading conditions; the excitability of spinal motoneurons was studied during passive and voluntary stepping movements. Passive stepping movements with characteristics maximally close to those during voluntary stepping were accomplished by the experimenter. The bursts of muscular activity during voluntary and imposed stepping movements were compared. In addition, the influence on the leg movement of artificially created loading onto the foot was studied. The excitability of spinal motoneurons was estimated by the amplitude of modulation of the m. soleus H reflex. Changes in the H reflex (Hoffmann’s reflex) after fixation of the knee and hip joints were also studied. In most subjects, passive movements were accompanied by bursts of electromyographic (EMG) activity in the hip muscles (sometimes in shank muscles); the timing of the EMG burst during the step cycle coincided with the burst’s timing during voluntary stepping. In many cases, the bursts in EMG activity exceeded the activity of homonymous muscles during voluntary stepping. Simulation of foot loading influenced significantly the distal part of the moving extremity during both voluntary and passive movements, which was expressed in the appearance of movements in the ankle joint and an increase in the phasic EMG activity of the shank muscles. The excitability of motoneurons during passive movements was higher than during voluntary movements. Changes and modulation of the H reflex throughout the step cycle were similar without restriction of joint mobility and without hip joint mobility. Fixation of the knee joint was of great importance. It is supposed that imposed movements activate the same mechanisms of rhythm generation as supraspinal commands during voluntary movements. During passive movements, presynaptic inhibition depends mostly on the afferent influences from the moving leg rather than on the central commands. Under the conditions of “air-stepping,” the afferent influences from the foot pressure receptors are likely to interact actively with the central program of stepping and to determine the final activity pattern irrespective of the movement type (voluntary or passive).