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PubMed1990

Relationships between orientation, movement and posture in weightlessness: preliminary ethological observations.

Weightlessness in man induces changes in astronaut orientations and consequently in his patterns of movements and postures. An ethological method has been used to describe the "overall" spontaneous behaviour of astronauts as seen from video recordings made during Space Flights. The work has consisted in analysing the relationships between orientation, movement and posture as an indication of a motor adaptative reorganization in such a situation. The results obtained lead us to consider three different aspects: (1) Orientation references. The astronaut orientates himself with reference to the Space Shuttle's internal structure; the increase of visual activity confirms the choice of the retinal vertical as frame of reference. (2) Motor coordination. The main data reveals a decrease in motor stereotypes by the diversity of motor acts observed and the importance of the link between orientation and posture described as follows: slightly inclined forward position, with legs flexed at about 135 degrees. (3) Cognitive references. There appears to be a new organization of the cognitive image of the body scheme, the missing vestibular information being supplied by peripheral vision instead which could play a role in the astronaut's perception of his own movement.

Astronauts↗

PubMed1994

Coordination changes associated with practice of a soccer kick.

The purpose of this study was to examine the changes in coordination associated with practice of a soccer kick. Video records were collected on 6 novice, right-footed soccer players prior to and after 20 regularly scheduled kicking practice sessions. Three experienced players were also videotaped for comparison. Movement of the right leg was digitized and analyzed using motion analysis software. As a result of practice, subjects were able to significantly increase the maximum resultant linear velocity of the foot, and these increases were accompanied by changes in the pattern of coordination underlying the movement. These changes were assessed qualitatively through the topological characteristics of the relative motions of the hip and knee and quantitatively through three different timing variables. The results provide some support for Bernstein's (1967) ideas on the acquisition of skilled behavior as well as for the two-stage model of motor learning proposed by Newell (1985).

Adolescent↗

PubMed2000

Affect regulation in alexithymia: an ethological study of displacement behavior during psychiatric interviews.

Displacement activities (i.e., self-directed behaviors such as self-touching, scratching, and self-grooming) are a reliable ethological indicator of increased emotional and physiological arousal throughout the phylogenetic scale. We hypothesized that, in alexithymic individuals, the failure to regulate cognitively distressing emotions might result in increased displacement behavior. The nonverbal behavior of 30 patients with depressive or anxiety disorders was video-recorded during psychiatric interviews and analyzed using an ethological scoring system. Before being interviewed, each patient completed the Twenty-Item Toronto Alexithymia Scale (TAS-20), the Beck Depression Inventory (BDI), and the state form of the State-Trait Anxiety Index (STAI-S). Ethological data confirmed the hypothesis of the study. The patients with more pronounced alexithymic features showed a significantly higher frequency of displacement activities during interviews. At the same time, these patients reported levels of self-rated anxiety and depression equivalent to those reported by nonalexithymic patients. Such a dissociation between cognitive appraisal of emotion and nonverbal behavior reflecting increased emotional arousal supports the view that alexithymia implies a failure to elevate emotions from a preconceptual level of organization to the conceptual level of mental representations.

Adolescent↗

PubMedDate not supplied

An assessment of football referees' decisions in incidents leading to player injuries.

PURPOSE: To assess whether match injuries to footballers occurred as a result of players' noncompliance with the rules of the game, match referees could reliably identify the legality of incidents leading to injury, and the rules of football were adequate to protect players from injury. METHODS: Video recordings of incidents leading to injury in 12 FIFA tournaments were used to identify parameters. Team physicians reported the details of match injuries. Two panels of FIFA referees reassessed the legality of incidents from these tournaments that resulted in injuries. RESULTS: In total, 148 general injuries and 84 head/neck injuries were assessed. For the general injuries, the match referees identified 47% and the referees' panel identified 69% as fouls. For head injuries, the match referees identified 40% and the referees' panel identified 49% as fouls. CONCLUSIONS: Decisions made on the legality of tackles leading to injury indicated that the current rules of football were adequate for the majority of tackle situations, although the reliability with which referees could identify fouls during some match conditions was low. For incidents leading to head/neck injuries, the match referees and the referees' panel both identified a smaller proportion of injury situations as fouls.

Adolescent↗

PubMed2004

Frictional properties of contacting surfaces in the hemelytra-hindwing locking mechanism in the bug Coreus marginatus (Heteroptera, Coreidae).

The structure and function of the hemelytra-to-hindwing locking mechanism of the bug Coreus marginatus were analysed. The system consists of a cuticular protrusion in the ventral side of the hemelytra, which locks the subcostal border of the hindwing in flight. The speed and distance slid by both surfaces against one another during flight were assessed using a combination of high-speed video recordings and a 2D geometrical model. The friction coefficient between sliding surfaces was assessed using a micromanipulator, coupled with force transducers. This was done under three experimental conditions: freshly dissected, air dried and rehydrated ethanol preserved samples. The results showed a high speed of sliding, approximately 0.18 m s(-1), with a relatively low friction coefficient (0.2 micro). There was no evident difference in the friction measured under the various treatments, with the exception of the rehydrated condition, which was lower. The surface morphology of the wing locking mechanism, namely outgrowths of one part having rounded edges, and completely flat surface on the counterpart, effectively aids in the reduction of friction at the microscopic level. The structure is effective even dry, and after being preserved in ethanol, suggesting that no cuticle secreted lubrication substance is responsible for its effectiveness. The ultrastructure presumably confers mechanical stability to the system under the high load it is subjected to in flight.

Animals↗

PubMed2003

Temporal patterns of caregiving for preterm infants indicate individualized developmental care.

OBJECTIVE: Individualized attention for premature infants was assessed from temporal patterns of caregiving at three very different regional NICUs. STUDY DESIGN: Continuous time-lapse video recording of 95 premature infants under 1500 g was made over three 24-hour periods when they were 33 weeks' and 35 weeks' conceptional age. STATISTICAL ANALYSIS: Analysis of variance was used to compare caregiving measures within and across hospitals. RESULTS: The tapes were scored in 5-minute epochs for periods when the infants were in and out of the crib, and when intervention/caregiving was occurring. Despite other differences, the three hospitals did not differ with respect to demographic and risk characteristics of the infant subjects. In all three hospitals, there was more out-of-crib and more caregiving during the daytime than at night; caregiving time showed individual differences over day and night periods; developmental changes in caregiving were observed over the 2 weeks; and more caregiving time was devoted to infants who were at greater risk. CONCLUSION: Temporal patterns of caregiving reliably indicate individual differences, with sensitive and responsive caregiving common to typical NICU nursing environments.

Humans↗

PubMed1991

Oral dysfunction in children with Down's syndrome: an evaluation of treatment effects by means of video registration.

The objects of the study were: (1) to analyse lip and tongue function in 24 children with Down's Syndrome as compared to an untreated control group of 19 healthy children; (2) to evaluate treatment effects of stimulation plates of the type Castillo Morales, in children with Downs' Syndrome. The range of the observation period during treatment was 4-11 months. Video recordings of 5 minutes (300 seconds) duration served as a basis for stop watch registrations of tongue protrusion and open mouth habit. Before treatment, the duration of tongue protrusion in the Downs' Syndrome group amounted to approximately half of the registration time as compared to an average of only 6.4 seconds in the control group. The values for lip closure differed only slightly. Following the insertion of the stimulation plate, the duration of tongue protrusion, in general, dropped markedly. No improvement in mouth closure or lip posture could be observed. A normalization of tongue function without the plate inserted was achieved after 4-11 months of treatment in 12 out of the 24 children. Follow-up registrations, ranging from 5 to 20 months, could be obtained in 7 out of the 12 successfully treated children. The results appeared to be stable in five of these children.

Child, Preschool↗

PubMed2001

Replacing the nucleus pulposus of the intervertebral disc.

OBJECTIVE: To determine whether replacement of the nucleus with a synthetic material would prevent the effects of nucleus removal. DESIGN: Laboratory experiments on excised tissues and a finite element model. BACKGROUND: Removal of the nucleus from the intervertebral disc causes the inner margins of the annulus to bulge inwards, instead of outwards, during compression. This may cause the annulus to degenerate further. METHODS: Video recordings of sheep discs, sectioned in the sagittal plane, were obtained during compression in a materials testing machine; the cut face of the disc was sealed with a Perspex window. Experiments were repeated with the nucleus removed and then replaced by a synthetic implant. A finite element model of an intact disc was also used to investigate the effect of nucleus replacement. RESULTS: When the nucleus of sectioned discs was replaced with the polymer materials, the inward bulging of the annulus was not observed. The predictions from the finite element model of the intact disc were consistent with this result. CONCLUSIONS: Replacement of the nucleus with a synthetic material can prevent the changes in annulus behaviour that result from removal of the nucleus. RELEVANCE: A suitable implant to replace the nucleus after surgical removal may help prevent inward bulging of the inner layers of the annulus.

Animals↗

PubMed2002

Differences in motility pattern between human buccal fibroblasts and periodontal and skin fibroblasts.

Migration of fibroblasts from surrounding normal tissue into the wound bed is an important requirement for successful wound healing. This study investigated the motility pattern of buccal, periodontal and skin fibroblasts to determine whether differences in the wound healing efficiency at these sites can be explained by differences in the motile behavior of their respective fibroblast populations. The migratory characteristics were studied in a two-dimensional culture system. The migration of single cells was time-lapse video recorded at intervals of 15 min for a period of 6 h using a computer-assisted microscope work-station. For evaluation of cell morphology, cell contours were recognized semiautomatically and used for determination of cell area, cell spreading and number and length of processes. We found that the cellular displacement of the buccal fibroblasts was only approximately 50% of the cellular displacement of periodontal and skin fibroblasts. The decreased cellular displacement of the buccal fibroblasts was found to be due to both lower cellular speed and less persistence in direction. The buccal fibroblasts also displayed smaller areas and longer processes. The differences in cellular morphology and motility pattern amongst the three fibroblast types could not be explained by differences in secretion of extracellular matrix components and are therefore believed to reflect phenotypic differences amongst fibroblast subpopulations.

Actins↗

PubMed2005

A comparative evaluation of oxygen consumption and gait pattern in amputees using Intelligent Prostheses and conventionally damped knee swing-phase control.

OBJECTIVE: To compare the gait of amputees wearing conventionally damped pneumatic swing-phase control knees and microchip-controlled Intelligent Prostheses. DESIGN: Crossover trial. SETTING: An amputee rehabilitation centre in a teaching hospital. PARTICIPANTS: Ten established unilateral transfemoral prosthetic users were asked to participate in the trial; all agreed. INTERVENTIONS: The amputees were assessed wearing pneumatic swing-phase control knees and then with the Intelligent Prosthesis. MAIN OUTCOME MEASURES: Oxygen consumption while walking at different speeds on a treadmill, video-recording of gait assessed by a panel and temporal-spatial parameters of gait whilst walking at slow, fast or normal speeds in a gait laboratory. RESULTS: Mean oxygen cost for all subjects at 0.69 m/s was 0.33 ml/kg.m with the conventional limb and 0.30 ml/kg.m with the Intelligent Prosthesis (p = 0.01). At 1.25 m/s the mean oxygen cost for the conventional limb was 0.24 ml/kg.m and for the Intelligent Prosthesis was 0.22 ml/kg.m (not significant). The ANOVA analysis showed that oxygen cost was similar at normal walking speeds but increased more at lower speeds for the pneumatic swing-phase control leg compared to the Intelligent Prosthesis (p < 0.02). There were no significant differences in subjective gait evaluation or temporal and spatial gait parameters. CONCLUSION: At lower speeds oxygen cost was lower with the Intelligent Prosthesis. Gait analysis detected no significant changes between the two legs.

Adult↗

PubMed1993

[Video-supported dynamic B-mode sonography of tongue function during swallowing].

A dynamic B-mode ultrasound technique supported by video recording was employed on 51 patients between the ages of six and 45 years for the purpose of imaging the tongue at rest and in motion during swallowing. All patients either in their case histories or at clinical examination demonstrated orofacial dysfunction of the tongue or an abnormal oral phase during swallowing. The ultrasound sequences of a 5 MHz sector scanner (100 degrees, 30 images/sec) were videotaped for the purpose of analyzing the sagittal and vertical movement components during swallowing. The sagittal sector scan revealed a visceral swallowing pattern in 21 patients. Noticeably often patients with an Angle class III malocclusion also displayed an abnormal swallowing pattern. Ultrasound scanning in the coronal and sagittal plane is a noninvasive imaging technique free of the biological risks associated with radiation. The dynamic ultrasound technique may be employed for early detection and diagnosis of tongue discoordinations and is especially to be recommended for the objective imaging and identification of tongue thrust in orthodontic patients.

Adolescent↗

PubMed1999

Measuring Drosophila (fruit fly) activity during microgravity exposure.

Important advances in the understanding of the aging process could be obtained through comprehension of the changes experienced by Drosophila melanogaster (fruit flies) during microgravity. Previous experiments flown on Cosmos satellites and various Space Shuttle missions have shown a significant decrease in the life span of young male Drosophila after microgravity exposure. Additionally, postflight analysis indicated an accelerated aging of the microgravity exposed male flies since they exhibited a significant decrease in mating ability and a consistently lower negative geotaxis response than the 1 g ground controls. The negative geotaxis response is the Drosophila's reaction to move opposite to the Earth's gravitational vector when disturbed in certain manners. Researchers have hypothesized that the accelerated aging, is due to an increased locomotor activity which causes a subsequent increase in mitochondrial activity. The increased mitochondrial activity, in turn, causes increased aging through accelerated damage to the mitochondrial system. An increase in locomotor activity was indicated by analyzing only a fraction (1/6th of a second) of the 15 minute video recordings of groups of Drosophila taken approximately every two days during a 14-day Space Shuttle flight. The increased locomotor activity may be related to the Drosophila's negative geotaxis response in that the flies may be reacting to the absence of normal gravity by continuously searching for the gravity vector. The aims of this study are to develop methods to accurately measure individual Drosophila activity, use these derived methods in 1 g to create a Drosophila activity baseline, and use the methods during short and long duration microgravity exposure (sounding rockets, parabolic flights, Space Shuttle, International Space Station, etc.) to examine Drosophila activity. The role of the negative geotaxis response on locomotor activity will be examined by using two strains of behaviorally selected Drosophila, one that exhibits a large or hyper negative geotaxis response and another that has a positive geotaxis response, in addition to examining flies with a normal or negative geotaxis response.

Aging↗

PubMed1998

Cell motility is inhibited by the antiepileptic compound, valproic acid and its teratogenic analogues.

Valproic acid (VPA) is an established human teratogen that causes neural tube defects in 1-2% of human foetuses exposed to the drug during early pregnancy. In this study, individual cell motility was evaluated using short- and long-term time-lapse video-recording and computer assisted image analysis, and it was found that VPA and selected VPA-analogues inhibited individual cell motility of L-cells in a dose-dependent manner. The compounds caused a decrease in the root-mean-square speed, S, and in the rate of diffusion, R, but an increase in the time of persistence in direction, P. Using short-term recordings and measurements of mean-cell speed, the reduction in the motile behaviour was shown to correlate with the teratogenic potency of the tested compounds. The observed effects of VPA on cell motility was independent of the employed L-cell clone, and could be reproduced in cells containing the neuronal marker NCAM and in the neuronal cell line N2a. Furthermore, the observed effect was independent of culture substratum, being observed for L-cells grown on fibronectin as well as on plastic. Immunofluorescence microscopy revealed that VPA-treatment of mouse L-cells caused a redistribution of F-actin and of a series of focal adhesion proteins, indicating that the effect of VPA on cell motility may be causally related to increased cell-substratum interactions or to alterations in the organisation or dynamics of the actin cytoskeleton.

Animals↗

PubMed1992

Computer-assisted video measurement of inhibition of ciliary beat frequency of human nasal epithelium in vitro by xylometazoline.

The effect of xylometazoline, an alpha-adrenergic agonist, on ciliary beat frequency (CBF) was tested on samples of human nasal epithelium in vitro. Ciliated tissue was obtained from the inferior nasal turbinates of five normal individuals. CBF was measured from video recordings of ciliary activity using a computer-assisted photometric technique. The mean CBF of cells from the five subjects, followed for 40 min without xylometazoline, was 12.0 +/- 1.1 Hz. All concentrations of xylometazoline significantly decreased ciliary beat frequency. After a 10-min exposure, the mean CBF dropped to 3.8 +/- 0.4 with 0.1% xylometazoline, 4.9 +/- 1.0 with 0.05%, and 8.1 +/- 0.9 with 0.025%. Washing with control culture medium at least partially reversed the inhibition within 10 min. Phentolamine (10(-3) M), an alpha-adrenergic antagonist, did not alter CBF significantly when used alone, but partially blocked the strong cilioinhibitory effect of xylometazoline. This action of xylometazoline is similar to that of several commercially prepared decongestants that contain potentially ciliotoxic preservatives in addition to alpha-adrenergic agonists and supports the view that alpha-adrenergic agonists act directly on ciliated cells to inhibit ciliary activity.

Adrenergic alpha-Agonists↗

PubMed2001

The effect of flexion angle on the macro and microscopic appearance of the rupture surface of the ACL of rabbits.

This study investigated how knee flexion angle affects the appearance of the rupture surface of the anterior cruciate ligament (ACL) using rabbit knees. Specimens were failed at flexion angles of 45 degrees and 90 degrees at displacement rates of 10 and 500 mm/min. Video recordings and scanning electron microscopy (SEM) studied the appearance of the rupture surfaces. At the displacement rate of 10 mm/min, the major mode of failure was fibre pullout for all flexion angles. At displacement rate of 500 mm/min, which more closely approximated loading conditions during trauma, we found that all modes of failure were exhibited. At 45 degrees flexion, the majority of specimens tested failed by avulsion. The reverse was true for specimens tested at 90 degrees where the majority of failures were fibre pullouts. At 45 degrees, there were more pulled-out fibres on rupture surfaces of specimens tested at 10 mm/min than at 500 mm/min. At 90 degrees, little difference was seen in the appearance of ruptures from both rates. SEM revealed that the waviness of collagen fibres was more pronounced at 10 mm/min. Therefore, the appearance of rupture surfaces of ACLs are affected by both flexion angle and displacement rate.

Animals↗

PubMed2002

Effects of the rider on the linear kinematics of jumping horses.

This study examined the effects of the rider on the linear projectile kinematics of show-jumping horses. SVHS video recordings (50 Hz) of eight horses jumping a vertical fence 1 m high were used for the study. Horses jumped the fence under two conditions: loose (no rider or tack) and ridden. Recordings were digitised using Peak Motus. After digitising the sequences, each rider's digitised data were removed from the ridden horse data so that three conditions were examined: loose, ridden (including the rider's data) and riderless (rider's data removed). Repeated measures ANOVA revealed significant differences between ridden and loose conditions for CG height at take-off (p < 0.001), CG distance to the fence at take-off (p = 0.001), maximum CG during the suspension phase (p < 0.001), CG position over the centre of the fence (p < 0.001), CG height at landing (p < 0.001), and vertical velocity at take-off (p < 0.001). The results indicated that the rider's effect on jumping horses was primarily due to behavioural changes in the horses motion (resulting from the rider's instruction), rather than inertial effects (due to the positioning of the rider on the horse). These findings have implications for the coaching of riders and horses.

Animals↗

PubMed2003

Dynamic performances of cattle transporting vehicle on Scandinavian roads and behavioural response of animals.

Driving performance, air quality in the vehicle, and handling during loading and unloading are the main factors, which could affect animal welfare. During transport of animals from farms to abattoirs, animals on the vehicle are subjected to vibrations in all directions. Performances of a typical vehicle for cattle transport have been studied under field commercial conditions. During the experiment, tri-axial vibrations on the vehicle, as well as velocity, slope and position were measured. The animals were video recorded for behavioral analyses. Geographical positions, speed and slope of roads were recorded using, GPS. Measurements were made with and without animals on the vehicle. The roads in the region are narrow almost everywhere, but rather plane and of good quality. Three road types were identified: straight and plain, curvy and graveled roads. Events such as sudden stops and curves were observed and noted. Vibration levels in tri-axial directions have been measured and analysed for different speeds and road types both when the vehicle was fully loaded and unloaded. There is a significant difference between the performances of the vehicle when loaded and unloaded. Very high vibrations values have been noted during the empty driving and these values were reduced by up to 9 times when the vehicle was loaded. Less vibrations amplitudes were observed and animals were calmer on ferry transport than on road transport. It has also been noted that animals prefer to stand perpendicular to the direction of vehicle's motion during transport.

Acceleration↗

PubMed1986

Video analysis of chemotactic locomotion of stored human polymorphonuclear leukocytes.

Previous studies of the storage of polymorphonuclear leukocytes (PMNs) have used an empirical approach to define "optimal" conditions. To date, no storage conditions have been described which satisfactorily preserve the chemotactic function of PMNs beyond 24 h. In an effort to define the precise nature of the storage lesion, we studied the chemotactic locomotion of freshly isolated PMNs and PMNs which had been suspended in citrate-phosphate-dextrose-adenine (CPD-A1) plasma and stored in PVC bags, at 20-22 degrees C for 24 h. We used time-lapse video recording and computer image analysis to quantitate the motion of PMNs migrating under agarose. The positions of individual motile cells were traced at 1-min intervals for 5 min. The following parameters were used to quantitate migration: speed (distance/min), persistence of locomotion index (velocity/speed), orientation angle (the angle of the vector describing the next displacement of a cell relative to a direct line toward the chemoattractant), and chemotropic index (cosine of the orientation angle). After 24 h of storage, the following changes were observed: fewer cells migrated, the speed of migrating cells was reduced by 25%, the persistence of locomotion index decreased by 7%, which indicates that migrating cells made slightly more/wider turns, and the chemotropic index was decreased by 30%, which indicates that migrating cells were less accurate in their orientation toward the chemoattractant. Apparently, the storage of PMNs selectively impairs the ability of some cells to orient accurately in a chemotactic gradient and changes the distribution of these locomotor parameters within the population.

Blood Preservation↗