Temporomandibular joint disorder in a patient with multiple sclerosis--review of literature with a clinical report

Temporomandibular disorders are a form of musculoskeletal disorders, which reduce the function of stomatognathic system and they are related to some other diseases causing painful conditions and disorders of oral function. The aim of this paper is to describe a one year follow up clinical case of a female patient with comorbid multiple sclerosis and a relatively rare form of articular disc disorder. Primary clinical diagnostics encompassed manual methods of TMJ examination. Definite diagnosis included radiologic examination. Clinical hyperextensive condyle position was palpated bilaterally and subsequently confirmed by a functional panoramic radiograph of TMJ. The anterior displacement of disc with reduction was diagnosed by magnetic resonance and in the right joint there was a disc displacement upon excursive movement. From relevant literature, the relationship of a number of diseases that can be related to functional disorder of the orofacial system, such as multiple sclerosis, has been described from many aspects. Also, apart from the standard classification of one form of anterior displacement of the disc, made primarily by magnetic resonance, cases of disc displacement upon excursive mandibular movement can rarely be found in literature.     

Osteonecrosis of the jaw

This review looks at osteonecrosis in the stomatognathic system (mainly the jaws). Osteonecrosis of the jaw (ONJ) is a rare but serious clinical condition. It affects patients treated with bisphosphonates, and also with denosumab, mainly in oncological doses. In osteoporosis, it is a problem of relatively small significance. Article presents a thorough review of this phenomenon, including its definition, pathogenesis, risk factors, prevention and treatment methods, and its incidence rate.     

Self-organisation in streams: the relationship between movement behaviour and body condition in a headwater salamander

1. When movement behaviour is correlated with traits affecting fitness, it may affect population performance directly, independent of extrinsic habitat conditions. 2. In a previous 3‐year, capture–recapture study, upstream movement by the salamander Gyrinophilus porphyriticus compensated for low reproduction in the upper 500 m of Merrill Brook, a first‐order stream in northern New Hampshire (U.S.A.). This immigrant subsidy resulted from excess reproduction in the downstream section (i.e. the lower 500 m of stream length) and from consistently upstream‐biased movement by salamanders. Reproduction in the two stream sections was positively correlated with mean body condition. Using 6 years of capture–recapture data, this study examines whether the movement behaviour of G. porphyriticus is related to body condition and thereby directly influences mean body condition and reproduction in the two sections of Merrill Brook. 3. Upstream‐biased movement and greater mean body condition in the downstream section were consistent across 6 years of data collection. In Merrill Brook and four other streams, however, individuals with high body condition were more likely to move upstream and low‐condition individuals were more likely to move downstream. Movement direction was unrelated to the size, sex and initial location of individuals. Body condition was positively related to growth rate, further supporting its link to reproductive potential, and positively autocorrelated through time in individuals that moved. 4. Results of this 6‐year study suggest that the movement behaviour of G. porphyriticus partially compensated for environmental factors differentiating mean body condition and reproduction along Merrill Brook and illustrate the potential for this form of self‐organisation to occur in linear habitats such as streams and rivers.     

From Molecules to Mating Success: Integrative Biology of Muscle Maturation in a Dragonfly

SYNOPSIS. Dragonflies begin adult life as comparatively weakfliers, then mature to become one of nature's ultimate flyingmachines. This ontogenetic transition provides an opportunityto investigate the relationship between life history, phenotypicplasticity, and changing ecological demands on organismal performance.Here we present an overview of a wide-ranging study of dragonflymuscle maturation that reveals i) ecological changes in theneed for efficient versus high-performance flight, ii) organism-level changes in performance, thermal physiology, locomotormechanics, and energy efficiency, iii) tissue-level changesin muscle ultrastructure and sensitivity to activation by calcium,and iv) molecular-level changes in the Lsoform composition ofa calcium regulatory protein in flight muscle (troponin-T).We discuss how these phenomena may be causally related, andthereby begin to show linkages across many levels of biologicalorganization. In particular, we suggest that alternative splicingof troponin-T mRNA is an important component of the "gearing"of muscle contractile function for developmental changes inwingbeat frequency and ecological demands on flight performance.Age-variable gearing of muscle function allows energeticallyeconomical flight during early adult growth, whereas power outputis maximized at maturity when aerial competition determinessuccess during territoriality and mating.     

Effect of low pass filtering on joint moments from inverse dynamics: implications for injury prevention

Analyses of joint moments are important in the study of human motion, and are crucial for our understanding of e.g. how and why ACL injuries occur. Such analyses may be affected by artifacts due to inconsistencies in the equations of motion when force and movement data are filtered with different cut-off frequencies. The purpose of this study was to quantify the effect of these artifacts, and compare joint moments calculated with the same or different cut-off frequency for the filtering of force and movement data. 123 elite handball players performed sidestep cutting while the movement was recorded by eight 240 Hz cameras and the ground reaction forces were recorded by a 960 Hz force plate. Knee and hip joint moments were calculated through inverse dynamics, with four different combinations of cut-off frequencies for signal filtering: movement 10 Hz, force 10 Hz, (10-10); movement 15 Hz, force 15 Hz; movement 10 Hz, force 50 Hz (10-50); movement 15 Hz, force 50 Hz. The results revealed significant differences, especially between conditions with different filtering of force and movement. Mean (SD) peak knee abduction moment for the 10-10 and 10-50 condition were 1.27 (0.53) and 1.64 (0.68) Nm/kg, respectively. Ranking of players based on knee abduction moments were affected by filtering condition. Out of 20 players with peak knee abduction moment higher than mean+1S D with the 10-50 condition, only 11 were still above mean+1 SD when the 10-10 condition was applied. Hip moments were very sensitive to filtering cut-off. Mean (SD) peak hip flexion moment was 3.64 (0.75) and 5.92 (1.80) under the 10-10 and 10-50 conditions, respectively. Based on these findings, force and movement data should be processed with the same filter. Conclusions from previous inverse dynamics studies, where this was not the case, should be treated with caution.     

Movement mechanics as a determinate of muscle structure, recruitment and coordination

During muscle contractions, the muscle fascicles may shorten at a rate different from the muscle-tendon unit, and the ratio of these velocities is its gearing. Appropriate gearing allows fascicles to reduce their shortening velocities and allows them to operate at effective shortening velocities across a range of movements. Gearing of the muscle fascicles within the muscle belly is the result of rotations of the fascicles and bulging of the belly. Variable gearing can also occur as a result of tendon length changes that can be caused by changes in the relative timing of muscle activity for different mechanical tasks. Recruitment patterns of slow and fast fibres are crucial for achieving optimal muscle performance, and coordination between muscles is related to whole limb performance. Poor coordination leads to inefficiencies and loss of power, and optimal coordination is required for high power outputs and high mechanical efficiencies from the limb. This paper summarizes key studies in these areas of neuromuscular mechanics and results from studies where we have tested these phenomena on a cycle ergometer are presented to highlight novel insights. The studies show how muscle structure and neural activation interact to generate smooth and effective motion of the body.     

The role of rapid dispersal in the population dynamics of competition

A dynamical equation for the spatial distribution of competing species that contains a growth term and a dispersal term is analyzed under the condition that the dispersal rate is sufficiently rapid compared to the growth rate. With this assumption, the equation becomes analogous to the niche-partitioning theory of MacArthur and Levins (1967, Amer. Natur. 101, 377–385) and thus provides a link between the theory of local niche partitioning and the theory of regional habitat segregation. The formulation is applied to a two species system consisting of a specialist and a generalist competing with each other in an environment composed of two different habitats. The analysis shows that dispersal due to directed movement toward a favorable habitat and density dependent random movement both facilitate coexistence.     

A gearing mechanism with 4 degrees of freedom for robotic applications in medicine]

Applications in robot-aided surgery are currently based on modifications of manipulators used in industrial manufacturing processes. In this paper we describe novel rotatory kinematics for a manipulator, specially developed for deployment in robot-aided surgery. The construction of the gearing mechanism used for the positioning and orientation of a linkage point is described. Forward and inverse kinematics were calculated, and a constructive solution proposed. The gearing mechanism is based on two disk systems, each of which consists of two opposing rotatable discs. The construction was designed in such a way that the linkage point can be positioned freely anywhere within the mechanism's range of motion. The kinematics thus permits an x-y-positioning via rotating movements only. The spatial arrangement of two of such disc systems permits movements in four degrees of freedom (DOF). The construction is compact, but can be further miniaturized, is flexible and manufacturing costs are low. On the basis of this mechanical concept a new, small automated manipulator for surgical application will be developed.     

Restricted movement by mottled sculpin (pisces: cottidae) in a southern Appalachian stream

1. We used direct observation and mark‐recapture techniques to quantify movements by mottled sculpins (Cottus bairdi) in a 1 km segment of Shope Fork in western North Carolina. Our objectives were to: (i) quantify the overall rate of sculpin movement, (ii) assess variation in movement among years, individuals, and sculpin size classes, (iii) relate movement to variation in stream flow and population size structure, and (iv) quantify relationships between movement and individual growth rates. 2. Movements were very restricted: median and mean movement distances for all sculpin size classes over a 45 day period were 1.3 and 4.4 m respectively. Nevertheless, there was a high degree of intrapopulation and temporal variation in sculpin movement. Movement of juveniles increased with discharge and with the density of large adults. Movement by small and large adults was not influenced by stream flow, but large adults where more mobile when their own density was high. Finally, there were differences in the growth rates of mobile and sedentary sculpins. Mobile juveniles grew faster than sedentary individuals under conditions of low flow and high density of large adults, whereas adults exhibited the opposite pattern. 3. Our results support the hypothesis that juvenile movement and growth is influenced by both intraspecific interactions with adults and stream flow. In contrast, adult movement appears to be influenced by competitive interactions among residents for suitable space. The relationship between movement and growth may provide a negative feedback mechanism regulating mottled sculpin populations in this system.     

Determining the movements of the skeleton using well-configured markers

The problem of determining skeletal movements in three dimensions by using a number of landmarks is treated. We present a method that determines the motion of a rigid body by using the positions of the landmarks in least-squares sense. The method uses the singular value decomposition of a matrix derived from the positions of thelandmarks. We show how one can use this method to express movement of skeleton segments relative to each other. As many others have pointed out, the movement can be very ill determined if the landmarks are badly configured. We present a condition number for the problem with good geometrical properties. The condition number depends on the configuration of the landmarks and indicates how to distribute the landmarks in a suitable way.     

A new method for measuring power output in a single leg extension: feasibility, reliability and validity

A method is described for measuring the explosive power of the leg in extension which has been found safe and acceptable for all age groups and levels of physical capability. The extension movement takes 0.25-0.40 s in a push through 0.165 m against a flat pedal. At the end of the push the leg is fully extended. The movement is made seated so that the forces are contained between the buttocks and the foot. The seat position is adjusted for leg length and the push is transmitted by a lever and chain to spin a flywheel. The gearing is such that resistance to the movement remains velocity of the flywheel is measured by an optoswitch and used to calculated the average leg extensor power (LEP) in the push. The reliability of the power measurement was evaluated in 46 subjects ranging in age from 20 to 86 years; they included medical students and geriatric day patients. They were tested on two occasions separated by a week. The maximal values on the first occasion (best of at least five trials) ranged from 30 to 300 W (mean +/- 1 SD = 154 +/- 88 W). There was no significant difference on re-test and the coefficient of variation was 9.4%. In a subgroup of 9 non-naive subjects who were measured by an experienced observer it was 6.3%. As expected, power was lower in women than in men and declined sharply with age. The sex difference was less when the values were expressed as power per body mass; a sharp age-related decline remained.(ABSTRACT TRUNCATED AT 250 WORDS)     

The multilayer growth of epithelium-like ESK cells in perfused cultures]

The multilayer growth of an epithelium-like ESK [correction of SPEV] cell culture was achieved under condition of culture medium perfusion. The growth of the ESK [correction of SPEV] cells is described under conditions excluding medium movement above the cells in the chamber with a semipermeable membrane separating the cells from the perfused medium. Under these conditions the multilayer (30-40 layers) growth of culture was observed. The data observed are in favour of our suggestion that it is the diffusional limitations in mass exchange, rather than intracellular interaction contacts, that may be responsible for cell growth in culture. A dependence of culture growth on the initial inoculation density, under condition of medium perfusion immediately above the cells, was determined. The dependence of the multilayer saturation density on the perfusion rate and on the complete replacement of the perfused medium is discussed. The existence of a limiting saturation density of perfused culture was shown.     

Muscle activity patterns during quick increase of movement amplitude in rapid elbow extensions

In this study, we investigated a motor strategy for increasing the amplitude of movement in rapid extensions at the elbow joint. This study focused on the changes in a triphasic electromyographic (EMG) pattern, i.e., the first agonist burst (AG1), the second agonist burst (AG2) and the antagonist burst (ANT), for increasing the amplitude of movement required after the initiation of movement. Subjects performed 40° (Basic task) and 80° of extension (Wide task). These tasks were performed under two conditions; performing a predetermined task (SF condition) and performing a task in response to a visual stimulus immediately after movement commencement (ST condition). Kinematic parameters and EMG activity from the agonist (triceps brachii) and the antagonist (biceps brachii) muscles were recorded. As a result, the onset latency of AG1 and AG2 and the duration of AG1 were longer under the ST condition than the SF condition. No difference was observed between the SF and ST condition with respect to ANT activity. It is concluded that the motor strategy for increasing the amplitude of movement after the initiation of movement was to control the movement velocity and the timing to stop movement by the coactivation duration of AG1 and ANT and to stop the desired position accurately by AG2 activity.     

Effects of passive and active movement on vibrotactile detection thresholds of the Pacinian channel and forward masking

Abstract

We investigated the gating effect of passive and active movement on the vibrotactile detection thresholds of the Pacinian (P) psychophysical channel and forward masking. Previous work on gating mostly used electrocutaneous stimulation and did not allow focusing on tactile submodalities. Ten healthy adults participated in our study. Passive movement was achieved by swinging a platform, on which the participant’s stimulated hand was attached, manually by a trained operator. The root-mean-square value of the movement speed was kept in a narrow range (slow: 10–20?cm/s, fast: 50–60?cm/s). Active movement was performed by the participant him-/herself using the same apparatus. The tactile stimuli consisted of 250-Hz sinusoidal mechanical vibrations, which were generated by a shaker mounted on the movement platform and applied to the middle fingertip. In the forward-masking experiments, a high-level masking stimulus preceded the test stimulus. Each movement condition was tested separately in a two-interval forced-choice detection task. Both passive and active movement caused a robust gating effect, that is, elevation of thresholds, in the fast speed range. Statistically significant change of thresholds was not found in slow movement conditions. Passive movement yielded higher thresholds than those measured during active movement, but this could not be confirmed statistically. On the other hand, the effect of forward masking was approximately constant as the movement condition varied. These results imply that gating depends on both peripheral and central factors in the P channel. Active movement may have some facilitatory role and produce less gating. Additionally, the results support the hypothesis regarding a critical speed for gating, which may be relevant for daily situations involving vibrations transmitted through grasped objects and for manual exploration.     

Interplay between Allee effects and collective movement in metapopulations

Population growth can be positively or negatively dependent on density. Therefore, the distribution pattern of individuals in a patchy environment can greatly affect the growth of each subpopulation and thereby of the metapopulation. When population growth presents positive density‐dependence (Allee effect), the distribution pattern becomes crucial, as small populations have an increased extinction risk. The way in which individuals move between patches largely determines the distribution pattern and thereby the population dynamics. Collective movement, in particular, should be expected to increase the potential number of colonisers and therefore the probability of colonising success. Here, we use mathematical modelling (differential equations and stochastic simulations) to study how collective movement can influence metapopulation dynamics when Allee effects are at stake. The models are inspired by the two‐spotted spider mite, a phytophagous pest of recognised agricultural importance. This sub‐social mite displays trail laying/following behaviour that can provoke collective movement. Moreover, experimental evidence suggests that it is subject to Allee effects. In the first part of this study we present a single‐species population growth model incorporating Allee effects, and study its properties. In the second part, this growth model is integrated into a larger simulation model consisting of a set of interconnected patches, in which the individuals move from one patch to the other either independently or collectively. Our results show that collective movement is more advantageous than independent dispersal only when Allee effects are present and strong enough. Furthermore they provide a theoretical framework that allows the quantification of the interplay between Allee effects and collective movement.     

Single Bacteria Movement Tracking by Online Microscopy – A Proof of Concept Study

In this technical report we demonstrate a low-cost online unit allowing movement tracking of flagellated bacteria on a single-cell level during fermentation processes. The system’s ability to distinguish different metabolic states (viability) of bacteria by movement velocity was investigated. A flow-through cuvette with automatically adjustable layer thickness was developed. The cuvette can be used with most commercially available laboratory microscopes equipped with 40× amplification and a digital camera. In addition, an automated sample preparation unit and a software module was developed measuring size, moved distance, and speed of bacteria. In a proof of principle study the movement velocities of Bacillus amyloliquefaciens FZB42 during three batch fermentation processes were investigated. In this process the bacteria went through different metabolic states, vegetative growth, diauxic shift, vegetative growth after diauxic shift, and sporulation. It was shown that the movement velocities during the different metabolic states significantly differ from each other. Therefore, the described setup has the potential to be used as a bacteria viability monitoring tool. In contrast to some other techniques, such as electro-optical techniques, this method can even be used in turbid production media.     

Movement of virus and photoassimilate in the phloem: A comparative analysis

Recent progress in the study of short-distance (cell-to-cell) movement of plant virus, facilitated by ‘movement proteins’, has led to a resurgence of interest in long-distance virus transport in the phloem. Relatively little is known about phloem-specific barriers to virus movement or about the form in which virus enters, travels within and exits this tissue. Progress in understanding virus and photoassimilate transport is limited by a paucity of information on the substructure and properties of plasmodesmata at specific interfaces. The direction of virus movement, once it has entered the phloem, can be understood by following photoassimilate translocation, a complex and dynamic process influenced by plant growth, development and vascular topology.     

Whisker growth in wild Eurasian badgers Meles meles: implications for stable isotope and bait marking studies

The use of biomarkers such as stable isotopes to study the foraging ecology and movement of animals is a rapidly expanding area of research. With respect to mammals, the analysis of inert keratinous tissue such as whiskers (vibrissae) is particularly attractive as they can be sequentially sampled to provide a long-term time series of individual movement or diet. However, in order to interpret data from such tissues researchers require details of growth rates and patterns, and also how these vary within populations. In this study, we use the fluorescent biomarker Rhodamine B to measure vibrissa growth rate and patterns in a wild population of Eurasian badgers. In addition, we compare stable isotope ratio values of blood and vibrissae in order to test whether vibrissae are retained for long periods following growth. We found that badger vibrissae grow at an average rate of 0.43 mm?day^?1 (range 0.23–0.83) such that single vibrissae sampled for stable isotope analysis contain an average of 104 days of ecological data. Age, sex and body condition did not affect growth rate, and there was no evidence of consistent individual differences in growth rate or long-term retention of vibrissae following growth. However, variation in growth rate within the population suggest that the temporal scales reflected in vibrissae may vary both between and within individuals, such that results are not always directly, temporally comparable. This research provides useful information for any future research using vibrissae in combination with biomarkers to study mammalian ecology.     

Bacterial swarming: a re-examination of cell-movement patterns

Many bacteria simultaneously grow and spread rapidly over a surface that supplies them with nutrient. Called 'swarming', this pattern of movement directs new cells to the edge of the colony. Swarming reduces competition between cells for nutrients, speeding growth. Behind the swarm edge, where the cell density is higher, growth is limited by transport of nutrient from the subsurface to the overlying cells. Despite years of study, the choreography of swarm cell movement, the bacterial equivalent of dancing toward an exit in a very dense crowd of moving bodies, remains a mystery. Swarming can be propelled by rotating flagella, and either by pulling with type IV pili or by pushing with the secretion of slime. By identifying patterns of movement that are common to swarms making use of different engines, a model of swarm choreography can be proposed.