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At least 451 records · Page 25Linked to original sources
PubMed2000

A new video-synchronized multichannel biomedical data acquisition system.

This data acquisition system records video frames onto a video tape, and simultaneously acquires biomedical data along with video time codes onto a computer hard disk to achieve a 30-min video-synchronized data recording with a summed data rate of 2.16 Mbit/s. A time-code-bridge-file created during acquisition matches each video frame-start with the corresponding index number of the acquired data. The mean synchronization accuracy of the system is 0.22 ms.

Computer Graphics↗
PubMed2000

An observation instrument for assessment of work technique in patient transfer tasks.

The aim of the study was to construct an observation instrument for description and assessment of nursing personnel's work technique in patient transfer tasks with regard to musculoskeletal health and safety, and to evaluate the validity and reliability of the instrument. The instrument consists of 24 items arranged in three phases of a transfer: the preparation phase, the starting position and the actual performance. Observations are made from video recordings. A detailed description of the individual's work technique, including actions taken to prepare the transfer, the interaction with the patient and any assistant co-worker, and the motor performance of the nurse, is provided. An attempt was made to quantify the assessments, by calculating an overall score of the work technique with regard to the level of musculoskeletal hazard and safety. The validity and reliability of the instrument were evaluated on 35 video-recorded patient transfers from hospital wards. The validity and reliability were mostly satisfactory, both when evaluating the agreements between the observations of each item (i.e. kappa values > 0.40), and when evaluating the agreements between the overall scores (i.e. intraclass correlation coefficients 0.71-0.90). Further improvements to enhance the agreements are suggested.

Back Injuries↗
PubMed1999

Night-time non-nutritive sucking in infants aged 1 to 5 months: relationship with infant state, breastfeeding, and bed-sharing versus room-sharing.

AIM: Epidemiological studies suggest that pacifier use may be protective against SIDS but little is known of the relationship between pacifier use and other forms of non-nutritive sucking (NNS) in infancy, or of patterns of NNS during the night, when most SIDS deaths occur. We report the first longitudinal study of NNS by direct overnight observations in healthy infants in a sleep laboratory. METHODS: Healthy, breast fed term infants (n = 10) were enrolled at birth, and sequential overnight polygraphic and infrared video recordings of infants with their mothers performed at monthly intervals from 1 to 5 months. Each month, mother baby pairs were randomized to 1 night bed-sharing (BN) then 1 room-sharing (RN), or vice versa. 'Episodes' of pacifier, own digit and mother's digit sucking (> 1 min) were identified and compared with state-matched control periods without sucking or feeding before and after each such episode. RESULTS: 329 episodes of NNS were identified in 749 h of video recording. The prevalence of pacifier sucking decreased with age, whilst digit sucking increased. Routine pacifier users rarely sucked their digits. There were temporal differences throughout the night in the distribution of different types of sucking and in infant state during and around sucking episodes. Sleeping in the 'non-routine' location was associated with a larger percentage of nights with sucking episodes and increased sleep latency. Bed sharing (routinely or on a given night) was associated with less sucking behavior and more breastfeeding. Non-nutritive sucking was not, however, associated with decreased total time breastfeeding per night or number of feeds per night. CONCLUSION: Patterns of NNS during the night change with age and are affected by maternal proximity. Digit sucking has state modulating effects, and may be suppressed by pacifier use. Thus any benefits of pacifier use must be set against the potential loss of a self-directed ability to modulate state during the night, and possible shortening of breastfeeding duration.

Beds↗
PubMed1984

An analysis of in vivo cell migration during teleost fin morphogenesis.

In the teleost embryo the pectoral fin bud initially displays an apical ectodermal ridge along its entire distal margin. The ridge subsequently becomes transformed into an apical fold as the distal ectodermal epithelium grows and folds to enclose an extracellular space between the apposed basal surfaces of the epithelium. Collagen fibrils up to 2 micron in diameter, termed 'actinotrichia', are deposited along the proximo-distal axis in two (dorsal and ventral) arrays. The actinotrichia are aligned parallel to one another with a regular spacing along the greater part of their length. Mesenchymal cells migrating distally from the base of the fin bud encounter the dorsal and ventral arrays of actinotrichia and move between them apparently using the fibrils as a substratum. The entire structure is transparent and, using the killifish Aphyosemion scheeli, we have investigated the migration of the mesenchymal cells between 135 and 220 h of development, using Nomarski interference contrast microscopy and time-lapse video recording. The number of cellular processes per cell increased significantly during the period of observation. These processes could be graded according to their diameters. Processes of diameter greater than 2 micron were not usually aligned along actinotrichia and arose at any aspect of the cell body. In contrast, processes with diameters less than 2 micron appeared to be confined to the distal aspects of the migrating cells and showed an increasing tendency to become aligned as development progressed. Time-lapse video recordings revealed that such aligned processes move faster (mean speed 17.98 (+/- 2.25) micron/h) than non-aligned processes (mean speed 4.66 (+/- 0.67) micron/h). Whole cell translocation was generally slower than rates of process movement: the lowest mean value (1.52(+/- 0.36) micron/h) was recorded between 135 and 160 h of development rising to a maximum mean rate (4.72(+/- 0.42) micron/h) between 195 and 220 h; the period of the fastest rate of cell translocation correlated with maximum process alignment along actinotrichia. Thin 1 micron plastic sections revealed that, generally, aligned processes were in close association with the surface of the actinotrichial fibrils and not the spaces between them.

Animals↗
PubMed2001

Transcript-based computer animation of movement: evaluating a new tool for nonverbal behavior research.

A new approach for the use of computer animation in experimental nonverbal research is introduced. The method was evaluated in a pilot study comparing video recordings of movement in dyadic interactions with computer animations based on transcripts of the behavior, to determine whether similar impression effects could be obtained. At the core of our development is a software tool allowing for the conversion of so-called position time-series protocols of movement into animation scripts for a professional computer animation platform. Our software combines computer-assisted movement transcription and editing with state-of-the-art 3-D animation technology. We present empirical evidence indicating remarkable overall correspondence between video recordings and computer animations. Due to the lack of facial activity in the computer animations, a decline in visual attention for the face area could be observed, which did not, however, affect the impression ratings.

Adolescent↗
PubMed2006

Use of surgical videos for realistic simulation of surgical procedures.

One of the major challenges in the development of virtual environments for medical simulations is photorealistic rendering, permitting high fidelity visual effects and user interaction. Digitized videos recorded from the laparoscopic camera are a rich source of information about surgical scenarios. How to fully utilize the information is important for improving the realism of the simulated scenarios. In reality, the camera viewpoint changes frequently and even for the same viewpoint, the scene is dynamic due to rhythmic heartbeat. Hence, the results of classical texture mapping are usually visually unappealing as they fail to capture the pulsatile effect, as well as other global illumination properties of the scene. In this paper we present a hybrid technique to improve the photorealistic rendering of the virtual surgery scenarios by spatio-temporally utilizing videos recorded during actual surgical procedures.

Computer Simulation↗
PubMed1996

Objective measurement of contact lens-induced conjunctival redness.

Ocular redness is the principal clinical sign of any inflammatory response affecting the anterior segment of the eye. The aims of the current investigation were: (1) to develop an objective method to quantify the severity and geographic distribution of redness, (2) to validate that technique by determining its precision and compare its finding to clinical rating, and (3) to apply this technique to evaluating the diurnal variation in ocular redness associated with daily and extended soft contact lens wear. The objective capture and analysis technique involved the following steps: (1) direct image formation on the CCD array of a high resolution, high sensitivity 3/4 inch Cohu camera via a Nikon Macrolens and (2) capture and image analysis with a PC-based dedicated transputer. The key steps were: filtering to accurately locate the limbus and electronic sectioning with differential intensity color analysis at fixed intervals away from the limbus. The technique gave a direct measurement of the number and size of the vessels present. The result obtained lead to the following conclusions: (1) the digitization and analysis of video recordings of the bulbar conjunctiva provide a precise measurement of the level of conjunctival redness, (2) subjective rating of low level of conjunctival redness, using an overall nine increment clinical scale, did not relate closely to the objective measurement of conjunctival redness, (3) for non-contact lens wearers, redness in the evening was similar to redness measured upon waking, and greater than redness 2 h postwaking. In contrast, in daily soft contact lens wearers, redness was maximal in the evening and greater than before insertion or during wear in the morning. In extended soft contact lens wearers, redness was maximal upon waking when it was greater than in the evening, and (4) digitization and analysis video recordings of the redness response of the bulbar conjunctiva are sufficiently sensitive clinical research tools to monitor diurnal variation of the inflammatory response of the anterior segment of the eye.

Circadian Rhythm↗
PubMed2002

Use of sonomicrometry demonstrates the link between prey capture kinematics and suction pressure in largemouth bass.

Suction feeding in fishes is the result of a highly coordinated explosive expansion of the buccal cavity that results in a rapid drop in pressure. Prey are drawn into the mouth by a flow of water that is generated by this expansion. At a gross level it is clear that the expansion of the buccal cavity is responsible for the drop in pressure. However, attempts using high-speed video recordings to demonstrate a tight link between prey capture kinematics and suction pressure have met with limited success. In a study with largemouth bass Micropterus salmoides, we adopted a new technique for studying kinematics, sonomicrometry, to transduce the movement of skeletal elements of the head during feeding, and synchronized pressure recordings at a sampling rate of 500 Hz. From the positional relationships of six piezoelectric crystals we monitored the internal movements of the buccal cavity and mouth in both mid-sagittal and transverse planes. We found that peak subambient pressure was reached very early in the kinematic expansion of the buccal cavity, occurring at the time when the rate of percentage change in buccal volume was at its peak. Using multiple regression analyses we were consistently able to account for over 90%, and in the best model 99%, of the variation in buccal pressure among strikes using kinematic variables. Sonomicrometry shows great promise as a method for documenting movements of biological structures that are not clearly visible in the external view provided by film and video recordings.

Animals↗
PubMedDate not supplied

Epilepsy and seizure classification in 63 dogs: a reappraisal of veterinary epilepsy terminology.

The human definitions of epilepsy and seizure classification were applied rigidly to epileptic dogs to investigate whether the distribution of the seizure types and epilepsies of dogs is comparable to that of human beings. Sixty-three dogs were referred because of recurrent (> 2) epileptic seizures. Only dogs without previous or ongoing antiepileptic treatment were included. All dogs had a physical and neurologic examination and blood work that included a CBC and a biochemical profile. All owners were asked to complete a questionnaire, focusing on seizure development. In addition, video recordings of suspected seizure episodes were analyzed if available. In the majority of dogs where an intracranial lesion was suspected, a computerized tomography scan was performed. Sixty-five percent of the dogs experienced partial seizures with or without secondary generalization and 32% exhibited primary generalized seizures; in 3% of the dogs the seizures could not be classified. Twenty-five percent of these cases were classified as idiopathic, 16% as symptomatic, and 45% as cryptogenic epilepsy; in 14% of these a classification was not possible. Applying human definitions, the distribution of seizure types and epilepsy classifications in these dogs differed widely from those in previous reports of canine epilepsy, where generalized seizures and idiopathic epilepsy were most frequently reported. However, our findings are consistent with the results of several large studies of human epilepsy patients. In dogs with epilepsy, closer attention must be given to the detection of a partial onset of seizures. In this study, detailed questioning of the owners and when possible analysis of video recorded seizures, proved to be sufficient for diagnosing seizures with a partial onset in a significant number of dogs. Partial onset of seizures may be an indication of underlying cerebral pathology. Some adjustments of veterinary epilepsy terminology are suggested.

Animals↗
PubMed1999

The development of the DEGR(R): A scale to assess pain in young children with cancer.

The Gustave Roussy Child Pain Scale (Douleur Enfant Gustave Roussy, DEGR(R)Scale) is a scale for grading prolonged pain in children aged 2-6 years with cancer. The scale comprised six behaviours specific to pain items, five psychomotor inertia items, and four anxiety items, with a total score ranging from 0 to 60. This work was designed to confirm the scale structure and to study its construct validity and convergent validity.Our work was composed of two parts. In the first part of the study, 152 children with progressive cancer were scored by two nurses using the DEGR(R)scale, in a cross-sectional design. And in the second part, 53 of these 152 children were video-recorded. The tapes were assessed both by a panel of four pain specialists using a 0 to 7 Likert scale and by a nurse using DEGR(R)scale.As for the 152 children, the mean of the total scores derived from the DEGR(R)is 20.2 (SD = 6.2). Both the degree of agreement between the nurses (the weighted kappa coefficient) and the internal consistency of the scale (Cronbach alpha coefficient = 0.90) were high, providing evidence of good reliability. Multivariate factor analyses showed a first factor of intensity of pain (51% of the total variance) and a second factor (14% of the total variance) which distinguishes the psychomotor inertia items from the items concerning voluntary expression of pain. Also, the results showed that psychomotor inertia items contribute to both factors and that it is an important sign of prolonged pain. Construct validity was strengthened by the absence of correlation between DEGR(R)scores and variables not related to pain, including fever, neutropenia and anaemia (indicative of poor medical condition) and the absence of parents' visits (indicative of psychological distress).Concerning the 53 video-recorded children, the nurses' DEGR(R)ratings were strongly correlated with the specialists panel scores indicating a fairly good case for convergent validity. Copyright 1999 European Federation of Chapters of the International Association for the Study of Pain.

Journal Article↗
PubMed1992

Microinjection of biotin-tubulin into anaphase cells induces transient elongation of kinetochore microtubules and reversal of chromosome-to-pole motion.

During prometaphase and metaphase of mitosis, tubulin subunit incorporation into kinetochore microtubules occurs proximal to the kinetochore, at the plus-ends of kinetochore microtubules. During anaphase, subunit loss from kinetochore fiber microtubules is also thought to occur mainly from microtubule plus-ends, proximal to the kinetochore. Thus, the kinetochore can mediate both subunit addition and loss while maintaining an attachment to kinetochore microtubules. To examine the relationship between chromosome motion and tubulin subunit assembly in anaphase, we have injected anaphase cells with biotin-labeled tubulin subunits. The pattern of biotin-tubulin incorporation was revealed using immunoelectron and confocal fluorescence microscopy of cells fixed after injection; chromosome motion was analyzed using video records of living injected cells. When anaphase cells are examined approximately 30 s after injection with biotin-tubulin, bright "tufts" of fluorescence are detected proximal to the kinetochores. Electron microscopic immunocytochemistry further reveals that these tufts of biotin-tubulin-containing microtubules are continuous with unlabeled kinetochore fiber microtubules. Biotin-tubulin incorporation proximal to the kinetochore in anaphase cells is detected after injection of 3-30 mg/ml biotin-tubulin, but not in cells injected with 0.3 mg/ml biotin-tubulin. At intermediate concentrations of biotin-tubulin (3-5 mg/ml), incorporation at the kinetochore can be detected within 15 s after injection; by approximately 1 min after injection discrete tufts of fluorescence are no longer detected, although some incorporation throughout the kinetochore fiber and into nonkinetochore microtubules is observed. At higher concentrations of injected biotin-tubulin (13 mg/ml), incorporation at the kinetochore is more extensive and occurs for longer periods of time than at intermediate concentrations. Incorporation of biotin-tubulin proximal to the kinetochore can be detected in cells injected during anaphase A, but not during anaphase B. Analysis of video records of microinjection experiments reveals that kinetochore proximal incorporation of biotin-tubulin is accompanied by a transient reversal of chromosome-to-pole motion. Chromosome motion is not altered after injection of 0.3 mg/ml biotin-tubulin or 5 mg/ml BSA. These results demonstrate that kinetochore microtubules in anaphase cells can elongate in response to the elevation of the tubulin concentration and that kinetochores retain the ability to mediate plus-end-dependent assembly of KMTs and plus-end-directed chromosome motion after anaphase onset.

Anaphase↗
PubMed2001

Spontaneous reversal of nystagmus in the dark.

AIM: To report five children with horizontal jerk nystagmus in whom eye movement recordings in the dark revealed a spontaneous reversal in the direction of the nystagmus beat. Three patients were blind in one eye and were diagnosed as having a manifest latent nystagmus (MLN), and two patients had strabismus and congenital nystagmus (CN). METHODS: Eye movements were recorded using DC electro-oculography with simultaneous video recording, including infrared recording in total darkness. RESULTS: Four patients had decelerating velocity slow phase jerk nystagmus when recorded under natural lighting conditions; the fifth case had accelerating velocity and linear slow phase jerk nystagmus. Under absolute darkness, nystagmus reversed in direction of beat with a mixture of linear and decelerating velocity slow phase waveforms. One child with unilateral anophthalmos could wilfully reverse the beat direction of his nystagmus by trying to look with his blind eye in the light and dark. CONCLUSIONS: These observations support the theory that LN/MLN beat direction is determined by the "presumed" viewing eye and may be consciously controlled. The spontaneous reversal of beat direction in the dark suggests eye dominance is predetermined. Eye movement recordings identified mixed nystagmus waveforms indicating that CN (accelerating velocity slow phases) and LN/MLN (linear/decelerating velocity slow phases) coexist in these subjects.

Anophthalmos↗
PubMed2006

Effects on improvement of blood flow in the chronically compressed cauda equina: comparison between a selective prostaglandin E receptor (EP4) agonist and a prostaglandin E1 derivate.

STUDY DESIGN: Vasodilatation was studied in a model of experimental chronic cauda equina compression using measurements of vessel diameter on video recordings. OBJECTIVE: The vasodilative effect was compared between a prostaglandin E2 receptor (EP) subtype agonists (EP4 agonist) and a prostaglandin E1 (PGE1) derivate. SUMMARY AND BACKGROUND DATA: Reduction of blood flow is one important pathogenic factor of neurogenic intermittent claudication (NIC) for lumbar spinal canal stenosis. It is known that PGE1 improves the mean walking distance in patients with cauda equina compression type of NIC. There are four subtypes of EP: EP1, EP2, EP3, and EP4. EP4 is located in vessels of pigs and rabbits. A highly selective EP4 agonist, which has effects on dilatation of pig and rabbit vessels, has recently been developed. One may therefore assume that this agonist may improve blood flow in the chronically compressed cauda equina. METHODS: A total of 25 dogs were used. A plastic balloon inflated to 10 mm Hg was placed under the lamina of the seventh lumbar vertebra for 1 week. OP-1206 cyclodextrin clathrate (OP-1206 CD: prostaglandin E1 derivate) and ONO-4819 CD (a highly selective EP4 agonist) were intravenously administrated. The following 5 experimental groups were assigned: animals in group OP (3) (n = 5) and Group OP (10) (n = 5) received 3 eta g/kg per minute and 10 eta g/kg per minute of OP-1206 CD, respectively; those in Group EP (3) (n = 5) and Group EP (10) (n = 5) received 3 eta g/kg per minute and 10 eta g/kg per minute of ONO-4819 CD, respectively; and those in the control group (n = 5) received saline. After 7 days, the cauda equina was exposed and blood vessels of the second or third sacral nerve root were identified using a specially designed operation microscope equipped with a video camera. The diameters of the observed blood vessels were measured on video-recordings every 10 minutes until 60 minutes after administrating OP-1206 CD or ONO-4819CD. RESULTS: In the Groups OP (3), OP (10), and EP (10), the blood vessels were dilated and blood flow increased after injection of the agents. In the Group EP (10), the vessel diameter and blood flow increased significantly compared with that in the other four groups. In contrast, the blood vessels contracted and the blood flow was reduced in the Group EP (3). CONCLUSIONS: Our results suggested that the EP4 agonist at high concentrations might be a potential therapeutic agent since it is expected to increase blood flow in nerve roots in patients with spinal canal stenosis.

Alprostadil↗
PubMed2002

Frequency evolution during tonic-clonic seizures.

By using the Short Time Fourier Transform, we analyzed the EEG frequency evolution during tonic-clonic seizures on 18 scalp recordings corresponding to 7 patients admitted for Video-EEG monitoring. This information was correlated with clinical findings observed in the video recordings. From the time-frequency plots, we recognized patterns related with brain activity even when embedded in a background of muscle artifacts. In 13/18 seizures we found a clear frequency dynamics characterized by an activity originally localized at about 8 Hz, later slowing down to about 1.5 Hz. In the remaining cases muscle artifacts hinder the disclosure of a clear frequency evolution. The clonic phases started when the main frequency slowed down to about 3 Hz. We conclude that the Short Time Fourier Transform is very useful for a quantitative analysis of epileptic seizures, especially when muscle artifacts contaminate the recordings. We further conclude that the clonic phase starts as a response to brain activity that can be only established when brain oscillations are slow enough to be followed by the muscles.

Adult↗
PubMed1997

Permanent Electronic Storage of Angiographic Images in the Catheterization Laboratory: High-Resolution and Real-Time Acquisition on Optical Laserdiscs.

The use of electronic ÒfilmlessÓ media for long-term archiving of coronary angiograms has been impeded by the problems of image storage and data transfer among institutions. Although long-term analogue storage of the images is presently feasible, and much less costly than digital storage, processing has been limited to a 625 lines video format, not optimal for high quality images. We developed a bi-directional 1249/625 lines converter, able to store and to replay high resolution (1249 lines) video images, from Component Record Video (CRV) Optical Laser (Analogue) Videodisks. Image quality and medical relevance were evaluated five ways: 1) Outside experts compared 593 static images stored on CRV discs to the same images stored in a high-resolution digital format blinded to source of image. The four experts found no visual or medical difference in 98% of evaluated images and minor differences in the remainder. The differences in the remaining images were not consistent among experts. 2) Two of the experts also compared the enhanced CRV optically stored image to the image obtained on simultaneously recorded 35mm cine film, and found the enhanced CRV stored image to be superior or similar, but never inferior to the film image. 3) 90 representatives from 63 outside institutions compared images from both a digital hard drive and the enhanced CRV optical (analogue) storage displayed at a Windows based digital workstation. During the test they were blinded as to the source of the images. The representatives found no difference in image resolution, quality, diagnostic accuracy, and medical relevance. 4) We evaluated quantitative coronary angiography (QCA) on standard coronary test phantoms using enhanced CRV stored images digitally processed. The correlation of the enhanced CRV image to the actual size of the phantom vessels was similar to the results obtained in the literature from digitally stored images. 5) 78 arterial measurements ranging 0.65 to 4.85 mm were evaluated both from the digital hard disc (D) and the CRV optical disc (CRV), using the same QCA analytical package. The correlation coefficient and the Standard Error of the Estimate between D and CRV values were respectively 0.997 and 0.076, no systematic over or underestimation occurred, and the mean variability was inferior to 0.1 mm. CONCLUSION: High-Resolution CRV-optical storage represents a cost-effective solution for excellent image quality equivalent to digitally stored images, permitting permanent electronic archiving inside the cath-lab, and allowing digital image processing and digital image communication.

Journal Article↗
PubMed1984

Reliability of optic disk topographic measurements recorded with a video-ophthalmograph.

The video-ophthalmograph records the topography of the optic disk via simultaneous stereoscopic images which are stored and analyzed with the help of a microcomputer. This information is used to generate the vertical cup-disk ratio, the vertical optic disk diameter, the cup volume, and the neuroretinal rim area. To determine the reliability of the data, we recorded information for one eye of each of five patients ten times to determine the interphotographic error variance. We also analyzed one photograph for each of five patients ten times to determine the intraphotographic variance attributable to repeated analysis of the same photograph. The interphotographic and intraphotographic coefficients of variation were 2% to 18% and 2% to 7% respectively for these measurements.

Computers↗
PubMed1992

[Language competence of 14-year-old adolescents in relation to their sociocultural origin: results from a logopedic study in the framework of the Basel kindergarten study].

Between 1986 and 1988 speech and language abilities of a representative sample of 341 fourteen-year-old Basle schoolchildren were assessed as part of the 2nd Follow-up examination of the Basle Kindergarten-study. The language and speech test consisted of retelling and writing two stories, one of them played by tape-recorder, the other by video recorder. In addition three established language tests (Mottier-, IMK- and KLI-speechtest) were used. The results show significant differences between Swiss children and children of Italian workers in different test parts. There are also differences between boys and girls and between social classes. The high proportion of children with language difficulties is alarming. Parts of the tests used in this study were found to be appropriate for a screening of speech and language abilities.

Adolescent↗