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PubMed2005

A new video image analysis system to study red blood cell dynamics and oxygenation in capillary networks.

OBJECTIVE: The authors present a Measurement and Analysis System for Capillary Oxygen Transport (MASCOT) to study red blood cell (RBC) dynamics and oxygenation in capillary networks. The system enables analysis of capillaries to study geometry and morphology and provides values for capillary parameters such as diameter and segment length. It also serves as an analysis tool for capillary RBC flow characteristics, including RBC velocity, lineal density, and supply rate. Furthermore, the system provides a means of determining the oxygen saturation of hemoglobin contained within RBCs, by analysis of synchronized videotapes containing images at two wavelengths, enabling the quantification of the oxygen content of individual RBCs. METHODS: Video recordings of RBC flow at two wavelengths, 420 nm (isosbestic) and 436 nm (oxygen sensitive), are made using a dual camera video microscopy system. The 420-nm recording is used to generate images based on the variance of light intensity fluctuations that help to identify capillaries in a given field of view that are in sharp focus and exhibit flow of individual RBCs separated by plasma gaps. A region of interest enclosing the desired capillary is defined and a fixed number of successive video frames at the two wavelengths are captured. Next a difference image is created, which delineates the RBC column, whose width is used to estimate the internal diameter of the capillary. The 420-nm images are also used to identify the location and centroid of each RBC within the capillary. A space-time image is generated to compute the average RBC velocity. Lineal density is calculated as the number of RBCs per unit length of a capillary segment. The mean optical density (OD) of each RBC is calculated at both wavelengths, and the average SO(2) for each cell is determined from OD(436)/OD(420). RESULTS AND CONCLUSIONS: MASCOT is a robust and flexible system that requires simple hardware, including a SGI workstation fitted with an audio-visual module, a VCR, and an oscilloscope. Since the new system provides information on an individual cell basis from entire capillary segments, the authors believe that results obtained using MASCOT will be more accurate than those obtained from previous systems. Due to its flexibility and ease of extension to other applications, MASCOT has the potential to be applied widely as an analysis tool for capillary oxygen transport measurements.

Animals↗

PubMed1999

Microglial motility in the rat facial nucleus following peripheral axotomy.

Microglial motility was studied in living mammalian brain tissue using infrared gradient contrast microscopy in combination with video contrast enhancement and time lapse video recording. The infrared gradient contrast allows the visualization of living cells up to a depth of 60 microm in brain slices, in regions where cell bodies remain largely uninjured by the tissue preparation and are visible in their natural environment. In contrast to other techniques, including confocal microscopy, this procedure does not require any staining or labeling of cell membranes and thus guarantees the investigation of tissue which has not been altered, apart from during preparation. Microglial cells are activated and increase in number in the facial nucleus following peripheral axotomy. Thus we established the preparation of longitudinal rat brainstem slices containing the axotomized facial nucleus as a source of activated microglial cells. During prolonged video time lapse recordings, two different types of microglial cell motility could be observed. Microglial cells which had accumulated at the surface of the slice remained stationary but showed activity of the cell soma, developing pseudopods of different shape and size which undulated and which were used for phagocytosis of cell debris. Microglial phagocytosis of bacteria could be documented for the first time in situ. In contrast, ameboid microglia which did not display pseudopods but showed migratory capacity, could be observed exclusively in the depth of the tissue. Some of these cells maintained a close contact to neurons and appeared to move along their dendrites, a finding that may be relevant to the role of microglia in "synaptic stripping", the displacement of synapses following axotomy. This approach provides a valuable opportunity to investigate the interactions between activated microglial cells and the surrounding cellular and extracellular structures in the absence of staining or labeling, thus opening a wide field for the analysis of the cellular mechanisms involved in numerous pathologies of the CNS.

Animals↗

PubMed2004

Patient-centred communication: videotaped consultations.

The aim of this study is to analyse the way in which orthopaedic physicians manage consultations, and to identify those factors associated with patient-experienced satisfaction/dissatisfaction. This was explored both using a descriptive method and by analysing comments from patients. Consultations were videotaped; 18 physicians and 18 patients participated. Approximately 1 week after the consultation, the patient was shown the video recording and asked for his/her points of view and spontaneous reactions. Each time, the patient wished to say something, the video was stopped and the comments recorded. According to the patients' comments of the videotaped consultations four consultations were mainly positive, seven negative and seven neither completely positive nor completely negative. We analysed the positive and negative consultations using the Consultation Map (CM) method. The pattern in the positive consultations shows a greater flexibility. Statements regarding initial history and aetiology often move to and fro between other items, and the consultation as a whole was often characterised by this rapid change between items. The pattern in the negative consultations seems to indicate a slower motion; with longer time spent with few items and fewer items covered. The positive consultations were characterised by a greater prevalence of the items 'Sharing Understanding' and 'Involving the Patient in Management'. On the other hand, the negative consultations were characterised by more time spent with the items 'History of problems', and 'Patient Ideas'. This might be due to the patient having tried to express him/herself in order to present his/her views but the physician not following them up. In this study, the CM has been helpful in clarifying the difference between encounters experienced as satisfactory or dissatisfactory.

Adult↗

PubMed1990

[Pathogenesis and treatment of Zencker's diverticulum].

The aims of this study were: 1) To measure pharyngeal and upper oesophageal function manometrically at the same time as recording video images of the patient swallowing barium, in normal controls and patients with Zenker's diverticulum, and, 2) In those patients who progressed to surgery to biopsy the cricopharyngeus and compare the findings with biopsies from normal controls. Subjects were seated in front of a fluoroscope and video images of a barium swallow were synchronised with a multichannel recording catheter which contained 3 perfused side holes 1 cm apart (situated in the pharynx) and a 4 cm long perfused sleeve pressure sensor (positioned across the upper oesophageal sphincter). The coordination of the upper sphincter with swallowing, its relaxation, the pressures generated in the distal pharynx and the maximum luminal area of the open upper sphincter, were calculated for different volumes of barium swallowed in 11 patients with a Zenker's diverticulum (mean age 71 years, range 50-99) and 9 normal controls (mean age 65 years, range 55-86). Seven patients progressed to cricopharyngeal myotomy and their biopsies were compared with biopsies from 9 normal controls. In patients with Zenker's diverticulum intrapharyngeal pressures during barium swallows were significantly greater (p less than .05) and maximal luminal areas of the open sphincter were significantly less (p less than .05) than in control patients. In patients having a cricopharyngeal myotomy, intrapharyngeal pressures and maximum luminal areas returned to normal after surgery. The cricopharyngeus muscle of patients with a Zenker's diverticulum showed significantly increased fibrosis compared with normal controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

PubMed2001

Muscle power patterns in the mid-acceleration phase of sprinting.

To assess the role of the lower limb joints in generating velocity in the mid-acceleration phase of sprinting, muscle power patterns of the hip, knee and ankle were determined. Six male sprinters with a mean 100 m time of 10.75 s performed repeated maximal sprints along a 35 m indoor track. A complete stride across a force platform, positioned at approximately 14 m into the sprint, was video-recorded for analysis. Smoothed coordinate data were obtained from manual digitization of (50 Hz) video images and were then interpolated to match the sampling rate of the recorded ground reaction force (1000 Hz). The moment at each joint was then calculated using inverse dynamics and multiplied by the angular velocity to determine the muscle power. The results showed a proximal-to-distal timing in the generation of peak extensor power during stance at the hip, the knee and then the ankle, with the plantar flexors producing the greatest peak power. Apart from a moderate power generation peak towards toe-off, knee power was negligible despite a large extensor moment throughout stance. The role of the knee thus appears to be one of maintaining the centre of mass height and enabling the power generated at the hip to be transferred to the ankle.

Acceleration↗

PubMed1985

Collision with and avoidance of obstacles by blind cave fish Anoptichthys jordani (Characidae).

Blind Mexican cave fish (Anoptichthys jordani) were released into unknown surroundings and their swimming tracks were recorded. During the first 24 h in a new tank, i.e., in unfamiliar environments, the average swimming velocity of the fish was higher than during the remaining time in the tank. Collision with obstacles was recorded by an electrical contact detection method. Single frame analysis of video-recordings revealed that collision can be correlated with tail movements when the fish is close to an obstacle, whereas avoidance correlates with gliding during approach to an obstacle. These behavior patterns are discussed in the context of the flow field hypothesis and inhibition of the lateral line organ during movement.

Animals↗

PubMed1999

A new vestibulo-ocular reflex recording system designed for routine vestibular clinical use.

A new vestibulo-ocular reflex (VOR) recording system was developed, which consists of an infrared eye camera, a small velocity sensor and a frequency modulator. Using this system, the head velocity signal was frequency modulated and simultaneously recorded as a sound signal on the audio track of a Hi8 video recorder with eye images. This device enabled recording of the VOR response in routine vestibular clinical practice. The reliability and effectiveness of this system were estimated by recording and analysing the VOR response against manually controlled rotation in normal subjects (n = 22) and in patients with unilateral severe vestibular hypofunction (n = 11). VOR gain on clockwise rotation viewed from the top was defined as R gain, and counterclockwise rotation as L gain. Directional preponderance (DP%) was also calculated. VOR gain towards the diseased side was significantly lower than that towards the intact side, and also significantly lower than that of normal subjects. DP% of unilateral vestibular hypofunction cases was significantly larger than that of normal subjects. These findings indicate that this VOR recording system reliably detects severe unilateral vestibular hypofunction.

Adult↗

PubMedDate not supplied

Graviresponses of gliding and swimming Loxodes using step transition to weightlessness.

Cells of Loxodes striatus were adjusted to defined culturing, experimental solution O2-supply, temperature, and state of equilibration to be subjected to step type transition of acceleration from normal gravity, (1 g) to the weightless condition (microgravity) during free fall in a 500 m drop shaft. Cellular locomotion inside a vertical experimental chamber was recorded preceding transition and during 10 s of microgravity. Cell tracks from video records were used to separate cells gliding along a solid surface from free swimmers, and to determine gravitaxis and gravikenesis of gliding and swimming cells. With O2 concentrations > or = 40% air saturation gliders and swimmers showed a positive gravitaxis. In microgravity gravitaxis of gliders relaxed within 5 s whereas gravitaxis relaxation of swimmers was not completed even after 10 s. Rates of horizontal gliders (319 micrometers/s) exceeded those, of horizontal swimmers (275 micrometers/s). Relaxation of gravikinesis was incomplete after 10 s of microgravity. Analysis of the locomotion rates during the g-step transition revealed that gliders sediment more slowly, than swimmers (14 versus 45 micrometers/s). The gravikinesis of gliders cancelled sedimentation effects during upward and downward locomotion tending to maintain cells at a predetermined level inside sediments of a freshwater habitat. At > or = 40% air saturation, gravikinesis of swimmers augmented the speed of the majority of cells during gravitaxis, which favours fast vertical migrations of Loxodes.

Animals↗

PubMed2006

Anechoic stripe size influences accuracy of FAST examination interpretation.

OBJECTIVES: Accurate and precise interpretations of Focused Assessment with Sonography for Trauma (FAST) findings are important factors in managing trauma patients. The objectives were to analyze the influence of anechoic stripe (AS) size on interpretation accuracy by emergency physicians (EPs) and to assess the precision of FAST examination interpretation as a function of EP FAST experience. METHODS: A prospective comparison study of FAST examination interpretation by 11 emergency medicine faculty (FAC), nine community attending EPs (ATT), and nine senior emergency medicine residents (RES) was conducted; these physicians were then divided into more experienced and less experienced cohorts to assess precision. Participants interpreted video recordings of the four standard views from five FAST examinations (20 total video clips); each examination contained views with various AS sizes. Accuracy of FAST examination interpretation was calculated for each group stratified by size of AS. Precision (reproducibility) of FAST examination interpretation was assessed by calculating kappa values. RESULTS: With large, moderate, or no AS, no significant differences in accuracy were found between groups. For small AS, significant differences in accuracy were found between the ATT and RES groups and between the combined FAC + ATT group and the RES group. Kappa was good to excellent when the nth and the (n + 1)th experienced physicians in the more experienced cohort were compared. kappa values reflected that the more experienced cohort was more precise than the less experienced cohort. CONCLUSIONS: AS size visible on FAST examinations and EP experience level with FAST examination interpretation exerted a significant influence on the interpretation accuracy of videotaped FAST examinations. In addition, precision was enhanced by increased EP experience with FAST.

Abdominal Injuries↗

PubMed2003

Motion analysis of stereotyped hand movements in Rett syndrome.

BACKGROUND: Rett syndrome is a genetic developmental disorder, and stereotyped hand movements are a striking feature of this condition. The aim of the present study was to subject these movements to objective analysis and compare the results in one girl at different ages. METHOD: The hand movements of a 10-year-old girl with Rett syndrome were subjected to accurate, three-dimensional (3D) computerized motion analysis and compared to two-dimensional (2D) video analysis of the same girl at 3 years of age. RESULTS: Three-dimensional computerized analysis revealed regular patterns with strong coupling between the hands. Frequency analysis showed a dominant frequency at 1.2 Hz, with a higher component at 2.4 Hz that may relate to the activity of basic rhythm generators. The same coupling characteristics were extracted from standard, 2D video recordings made at the same time as the 3D capture. CONCLUSION: An informal video of the same girl taken when she was 3 years of age was analysed in the same way as the 2D video and showed the same characteristics, indicating the possible future use of automated video analysis for early screening and intervention evaluation.

Child↗

PubMed2005

A repetitive movement detector used for automatic monitoring and quantification of scratching in mice.

We have designed an economical non-invasive movement detector for small animal studies and used it for monitoring and quantifying itch in mice. The system is based on a sensitive force transducer positioned below a recording platform holding a lightweight polystyrene recording box in which an animal is placed. A programmed micro-controller is used to discriminate between non-specific movement, grooming behaviour, and scratching movements made by the animal's hind limb. Following sub-dermal injection of histamine receptor agonists into the neck of a mouse, dose-related scratching occurred which was detected and quantified. There was 91% correlation between bouts of scratching as counted manually from playback of the video recording and recorded by the detector. The detector was also able rapidly to count the individual scratch movements of the hind limb that comprise a bout, with 95% accuracy in comparison with manual counting during slow motion playback of video tape, something that is impossible for an unaided observer to achieve because individual scratch movements are too fast to discriminate by eye. Separate detectors were used for the efficient non-invasive study of four animals simultaneously, and this number could easily be increased by adding more platforms. The system could also be modified to record the animal's position within the box, which would be of value in studies involving exploratory behaviour. In summary, the non-invasive multichannel repetitive movement detector will be very useful for accurate measurement of scratching during pruritus studies in small animals, with considerable savings in staff time and effort. It should therefore be a valuable tool for helping to investigate pruritus and in the evaluation of anti-pruritic drugs.

Animals↗

PubMed1995

[A new two-chamber model for examination and demonstration of transdural fluid leakage after spinal anesthesia].

UNLABELLED: Various in vitro models have been introduced for comparative examinations of post-dural-puncture trauma and measurement of liquor leakage through puncture sites. These models allow simulation of subarachnoid, but not of peridural, pressure. A new two-chamber-model realizes the simulation of both subarachnoid and peridural pressure and allows observation of in vitro punctures with video-documentation. Frame grabbing and (computer-aided) image analysis show new aspects of spinal puncture effects. Therefore, post-dural-puncture trauma and retraction can be objectively visualized by this method, which has not previously been demonstrated. METHODS: Two-chamber-model consists of two short aluminium cylinders. Native human dura patches (8X8 mm) from fresh cadavers are put (correctly oriented) between two special polyamide seals. Mounted between the upper and lower cylinder, these seals stretch the dura patch, which remains flexible and even in all directions. After filling of the lower (subarachnoid) and upper (peridural) chamber with Ringer lactate solution, positive or negative physiological pressure can be adjusted by way of two (Ringer lactate solution filled) infusion lines in each chamber. Puncturing is performed at an angle of 57 degrees to the dura. The model allows examination with epi-illumination and transmitted (polarized) light. In vitro punctures are observed through an inverted camera lens with an CCD-Hi8 video camera (Canon UC1HI) looking into the peridural chamber and documented by means of an S-VHS video recorder (Panasonic NV-FS200EG). After true-colour frame grabbing by a video digitizer (Fast Screen Machine II), single video frames can be optimized and analysed with a 486-66 MHz computer and conventional software (Corel Draw 3.0, Photostyler 1.1a, DDL Aequitas 1.00b). Punctures demonstrated in this paper have been done under simulation of a transdural gradient of 20 cm water similar to the situation of a recumbent patient (15 cm water in the subarachnoid and -5 cm water in the peridural chamber). The punctures were followed by short-time observation for up to 10 minutes. RESULTS: By making it possible to obtains a picture of the puncture site at 20-ms intervals (because of the PAL norm of 50 half-frames/s), video-documentation has become accepted as superior to conventional photography. When the Ringer lactate solution in the subarachnoid chamber is stained with methylene blue, transdural leakage can easily be observed. The result of this documentation technique demonstrate that not dural puncture can be atraumatic, when a 29-G Quincke needle is used. Calculation on the difference between a digitized video frame before and after the puncture clearly illustrates the dural trauma. Owing to their non-cutting tip, as expected, pencil-point needles leave diffuse changes across the dura patch, whereas a more local trauma was observed after puncturing with cutting-tip needles. The same computer calculation between two video frames allows examination of post-puncture-dural retraction of the puncture site. In this connection, we found that relevant dural retraction is a phenomenon limited to the first minute after puncture. Thin spinal needles with so-called modern tips (e.g. Whitacre, Atraucan) can minimize the post-dural-puncture trauma, whereas thicker, conventional, spinal needles (Quincke) leave considerable dural defects. CONCLUSIONS: The two-chamber-model presented allows easy simulation of physiological subarachnoid and peridural pressure. The Ringer lactate solution in the subarachnoid chamber corresponds to the liquor, whereas that in the peridural chamber corresponds to the intercellular (peridural) space. The tension of the dural patch between the polyamide seals is similar to the situation in an anotomical model observed by spinaloscopy (in an earlier study). With the video documentation and computer-aided analysis technique introduced, dural trauma and retraction of the puncture site can be examined and demo

Anesthesia, Spinal↗

PubMed1998

Suppression of sigma spindle electroencephalographic activity as a measure of transient arousal after spontaneous and occlusion-evoked sighs and startles.

Defective arousal mechanisms are viewed as contributory to sleep hypopnea disorders and sudden infant death syndrome. Sighs (i.e. augmented breaths) as well as startles have not traditionally been viewed as arousal-related phenomena in infants. We hypothesized that, if sighs and startles are the initial event in a sequential arousal process, then they might be associated with specific EEG activity changes, because activation of the arousal-related ascending reticular activating system can suppress thalamus-generated sigma spindle oscillations. We studied spontaneous sighs and startles and those elicited by briefly occluding the infants face mask airway in 12 normal infants (age 10-19 wk) during non-rapid eye movement sleep. We recorded EEG (C3-P3), ECG, O2 saturation, diaphragmatic electromyography, limb electromyography, and video of the infant. The startle intensity was scored on a scale of 0 to 3 based on video recorded movements. Sleep spindle periodicity was analyzed by using a threshold over a compressed spectral band array. Spontaneous sighs and sleep startles were immediately followed by an interspindle interval prolongation from (mean +/- SEM) 8.0 +/- 0.16 s (control period) to 17.9 +/- 1.45 s after spontaneous sighs, to 23.8 +/- 1.26 s after spontaneous sighs accompanied by startles and to 26.5 +/- 1.45 s after occlusion-related sighs and startles. Furthermore, the intensity of occlusion-evoked startles was positively correlated with the interspindle interval prolongation (p < 0.01). We conclude that spontaneous as well as evoked sighs and startles are immediately followed by a transient sleep spindle suppression. This phenomenon indicates a close linkage between sighs, startles, and reticular formation-related arousal mechanisms.

Airway Obstruction↗

PubMed1999

Quantification of cellular properties from external fields and resulting induced velocity: magnetic susceptibility.

An experimental technique is discussed in which the magnetic susceptibility of immunomagnetically labeled cells can be determined on a cell-by-cell basis. This technique is based on determining the magnetically induced velocity that an immunomagnetically labeled cell has in a well-defined magnetic energy gradient. This velocity is determined through the use of video recordings of microscopic images of cells moving in the magnetic energy gradient. These video images are then computer digitized and processed using a computer algorithm, cell tracking velocimetry, which allows larger numbers (>10(3)) of cells to be analyzed.

Cells, Cultured↗

PubMed1975

Universal indirect tomography.

The procedure is performed in two stages. First, during the radiographic exposure, the patient is rotated in relation to the X-ray tube and a recording device, namely a cinefluorographic device or a television chain with a video-recorder. In practice the tube and the recording device will be revolved around the patient. Later on, in the second stage, the cinefluorographic image, or the television image of the rotating patient, is projected onto a photographic film. If this film is adequately rotated, a tomographic picture will be produced. The method can be applied to conventional tomography, zonography, transverse tomography, autotomography and orthopantomography.

Cineradiography↗

PubMed1997

The desk-top computer as a magic box: patterns of behaviour connected with the desk-top computer; GPs' and patients' perceptions.

BACKGROUND: The use of computers in general practice is becoming increasingly common. There has been concern about effects on doctor-patient communication. OBJECTIVES: The aim of this study was to identify common patterns in the use of desk-top computers by GPs with regard to interaction with the patients, and to assess the GPs' and patients' perceptions of the use of the computer. METHOD: Thirty-nine video-taped consultations with five different GPs were analysed inductively, inspired by the principles of 'grounded theory'. On separate occasions the five GPs and 12 of the previously video-taped patients watched and commented on the video recordings of their own consultation. RESULTS: The study showed that the computer was sometimes used in a way that was not originally intended. Use of the computer could be identified as a way of obtaining 'time-out' in the consultation. It could also be a referral to a 'magic box'. The conversation often changed when the computer was used. The interviews showed that the patients lacked understanding about the computer's functions. They also lacked knowledge about the possibility of loss of confidentiality with electronic files. The patients found it disturbing not knowing what their doctor was doing when he worked on the computer, and they preferred being able to see the computer screen. The GPs were surprised at how their own use of the computer looked on the video, and as a result of the interview they wanted to change their behaviour. CONCLUSIONS: It is concluded that patients need more information about the use of computers by GPs, and that GPs may benefit from paying more attention to their computer use.

Adult↗

PubMed1999

The roles of child reactivity and parenting context in infant pain response.

This study examined the relative importance of and developmental changes in biologically-based child variables (infant vagal tone and infant difficultness) and parental contextual variables (maternal behavior during pain and maternal sensitivity) in the prediction of infant pain behavior during immunization. Sixty infant-mother dyads were assessed when infants were approximately 6 or 18-months of age. During the first session, mothers completed a measure of infant difficultness, infants' resting EKG signals were recorded, and maternal sensitivity was rated. During the second session, infants' immunizations were video-recorded and maternal vocalizations and infant pain behavior were rated. At 6-months of age, 44% of the variability in infant pain behavior was predicted by infant difficultness and mothers' vocalizations during immunization. At 18-months of age, 35% of the variability in infant pain behavior was predicted by maternal sensitivity and infant vagal tone level. Children's emotion regulation skills and socialization histories may underlie age-related changes in the predictors of their pain.

Adaptation, Psychological↗

PubMed2006

An Internet-based abstinence reinforcement treatment for cigarette smoking.

Although voucher reinforcement has been shown to promote abstinence from smoking, more practical methods are needed to obtain objective evidence of smoking status on a frequent and sustained basis. Using a within-subject reversal design, the present study tested an Internet-based method to obtain objective evidence of smoking status and to deliver voucher incentives for evidence of abstinence. Twenty (10 females) heavy smokers completed this 4-week study. Twice daily, participants made video recordings of themselves providing a breath carbon monoxide (CO) sample with a web camera. The video was made at home and sent electronically to the smoking clinic. Participants could earn vouchers for gradual reductions in breath CO during a 4-day shaping condition, and then for achieving abstinence (CO < or = 7 ppm) during a 10-day abstinence induction phase. Vouchers could be exchanged for merchandise at select Internet vendors. Relative to baseline conditions, significant decreases in CO were observed during treatment, and many participants achieved sustained periods of abstinence. The study suggests that an Internet-based voucher reinforcement program is a feasible and effective method to promote abstinence from cigarette smoking.

Adult↗