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PubMedDate not supplied

Regional wall motion index for infarct and noninfarct regions after reperfusion in acute myocardial infarction: comparison with global wall motion index.

A regional wall motion index has been derived from two-dimensional echocardiograms by use of a 16-segment model that was subdivided into anterior (nine segments) and infero-postero-lateral (seven segments) regions. This new method is compared with the use of a previously described global wall motion index for the analysis of serial echocardiograms after reperfusion in 23 patients who had acute myocardial infarction. Mean global index improved from 1.84 +/- 0.46 to 1.56 +/- 0.37 at 24 hours (p less than 0.01) and to 1.50 +/- 0.29 after 3 days to 7 days (p less than 0.02), whereas mean regional index for infarct regions improved from 2.28 +/- 0.73 to 1.82 +/- 0.58 at 24 hours (p less than 0.01) and to 1.70 +/- 0.42 after 3 to 7 days (p less than 0.01), with no significant change in the noninfarct index (1.34 +/- 0.32 initially and 1.28 +/- 0.36 after 3 to 7 days). Although both global and regional indexes effectively demonstrate early recovery of left ventricular function, (within 24 hours in many patients), the regional index for infarct regions is higher than the global index and effectively distinguishes between infarct and noninfarct segments. An overlap index in which an additional apical segment is included in the anterior region (10 segments) for anterior infarctions and in the infero-postero-lateral region (eight segments) for inferior infarctions results in a greater differentiation between infarct and noninfarct regions, with the mean initial noninfarct overlap index (1.17 +/- 0.33) significantly less than the nonoverlap index.(ABSTRACT TRUNCATED AT 250 WORDS)

Echocardiography↗
PubMed2004

Comparison between angiographic right coronary artery motion and echocardiographic tricuspid annulus motion.

OBJECTIVE: To compare echocardiographic M-mode measurements of tricuspid annulus motion (TAM) with angiographic M-mode measurements of right coronary artery motion (RAM). DESIGN: Twenty-four patients were included and examined by echocardiography before the angiographic examination. The amplitudes and the velocities of TAM and the atrial contribution to the total amplitude of TAM were measured. The obtained values were compared with angiographic M-mode measurements of RAM at a proximal and a distal site of the second segment of the right coronary artery. RESULTS: There was no significant difference between several of the echocardiographic M-mode measurements of TAM and the angiographic M-mode measurements of RAM. However, the agreement was rather poor for some variables. CONCLUSION: Different parameters obtained from echocardiographic TAM are not interchangeable with values from angiographic RAM. If measurements of RAM are to be used in the assessment of right ventricular (RV) function further studies are needed to examine the correlation and agreement between RAM and different methods of measuring RV function, i.e. radionuclide angiography or magnetic resonance imaging.

Adult↗
PubMed1992

The Effect of Removing Superior Temporal Cortical Motion Areas in the Macaque Monkey: II. Motion Discrimination Using Random Dot Displays.

Nine macaque monkeys were trained to discriminate between a display in which all the dots moved randomly (visual dynamic noise) and an adjacent display in which a proportion of the dots oscillated coherently from side to side. Two monkeys in which area MT (middle temporal visual area) and adjacent regions were surgically removed were unable to perform even the simplest version of this task where the coherent motion was not masked by any visual dynamic noise. The other seven animals tolerated between 60% and 65% of random movement in the otherwise coherently oscillating display before they failed to discriminate between the two displays. In contrast, shape discrimination tasks containing luminance boundaries were unaffected by the removal of area MT. However, the removal of area MT did impair the animals' ability to use a kinetic boundary as the basis for shape discrimination. Their performance with a kinetic boundary between a moving and a stationary random dot field and a kinetic boundary between two random dot fields moving in opposite directions was the most severely impaired. Their performance with a kinetic boundary defined by two random dot fields moving orthogonally to each other was unimpaired. None of the animals from either group was able to use the kinetic boundary defined by coherent motion and visual dynamic noise as the basis for shape discrimination. The ease with which the control animals were able to employ the different types of kinetic boundaries to perform the shape discrimination reflected previously published proportions of cells in area MT that are specialized for detecting the different types of kinetic boundaries.

Journal Article↗
PubMed2000

Breath-hold three-dimensional contrast-enhanced coronary MR angiography: motion-matched k-space sampling for reducing cardiac motion effects.

A view order that matches k-space sampling to cardiac motion within the acquisition window was developed for breath-hold three-dimensional contrast material-enhanced coronary magnetic resonance angiography. In vivo experiments in seven volunteers demonstrated that blurring was substantially reduced with this motion-matched view order as compared with the standard centric view order. Coronary arteries were well delineated.

Adult↗
PubMed1999

[Relation between wall motion and scintigraphic uptake altered by the cut-off level on technetium-99m sestamibi tomographic imaging--the preferable cut-off levels according to tomographic uptake correlated with the wall motion].

BACKGROUND: Whether technetium-99m sestamibi imaging can evaluate myocardial viability is still obscure. It may be partially because the preferable cut-off level for evaluation of the viability is not known. OBJECTIVES: This study was aimed to investigate which cut-off level should be used for estimation of the contractile function, and verify whether technetium-99m sestamibi tomographic imaging can evaluate myocardial viability. METHODS: We studied 45 patients who had had myocardial infarction. They underwent technetium-99m sestamibi imaging, echocardiography, and cardiac catheterization. The myocardial image was divided into 16 segments, each of which was scored according to wall motion on echocardiography with a 4-point scale. The segmental technetium-99m uptake was also scored with a 4-point scale. We investigated the correlation between wall motion and scintigraphic uptake with the use of 7 cut-off levels (from 35% to 65%, in 5% increments). The correlation ranks were compared among patient groups with a number of stenotic vessels. RESULTS: Irrespective of the number of stenotic vessels, the defect score was similarly enlarged according to cut-off levels. The patient groups had the maximum correlation ranks with different cut-off levels, which were 40% for 1-vessel disease (rho = 0.512, n = 160, p = 0.0001), 50% for 2-vessel disease (rho = 0.424, n = 208, p = 0.0001), and 60% for 3-vessel disease (rho = 0.540, n = 272, p = 0.0001). The correlation ranks for all groups were stable, whereas not high, throughout various cut-off levels. CONCLUSIONS: Technetium-99m sestamibi imaging can approximately estimate myocardial viability from the point of view of function, which may be corrected by the careful choice of cut off levels according to the number of the stenotic vessels (40% for 1-vessel disease, 50% for 2-vessel disease, 60% for 3-vessel disease).

Coronary Circulation↗
PubMed1992

Direct imaging of the tricuspid valve annular motions by fiberoptic cardioscopy in dogs. I. Does De Vega's annuloplasty preserve the annular motions?

Applying the technology of direct imaging by fiberoptic cardioscopy, physiologic and pathophysiologic motions of the tricuspid valve anulus were studied in 10 anesthetized normal dogs (control group) and in 9 dogs that had chronic tricuspid regurgitation (TR group). The heart was perfused with transparent modified Tyrode's solution by working heart method, and the anuli, outlined by sutured beads, were observed and recorded on a high-speed video system in real time. Tricuspid valve annular area was calculated at 14 points during the cardiac cycle. The control group was studied in the normal condition, and the tricuspid regurgitation group was studied during four interventions: nontricuspid annuloplasty group and three tricuspid annuloplasty groups with reducing tricuspid valve annular area to 80%, 65%, and 50% of that of the non-tricuspid annuloplasty group by De Vega's procedure. Tricuspid valve annular area in the control group increased by 7% during atrial systole and was reduced by 34% mainly during ventricular systole, in which the free wall annular area and the septal annular area narrowed by an equal 34%. Chronic tricuspid regurgitation lessened tricuspid valve annular area narrowing to 20% in percent reduction (p < 0.01). In the TR group the decrease in tricuspid valve annular area narrowing was attributed mainly to lessened narrowing of the free wall anulus (percent reduction of tricuspid valve annular area, 19%; p < 0.01). The amplitudes in tricuspid valve annular area narrowing were unchanged in the tricuspid annuloplasty groups even when tricuspid valve annular area, was reduced to 50% by De Vega's tricuspid annuloplasty (percent reduction of tricuspid valve annular area, 16%; not significant). These findings suggest that De Vega's tricuspid annuloplasty is a reasonable method that does preserve the physiologic annular motions in the opening and closing mechanism of the tricuspid valve.

Animals↗
PubMed1984

Motion sickness incidence: distribution of time to first emesis and comparison of some complex motion conditions.

A statistical mixture model is used to fit time-to-emesis data. The Weibull probability distribution is shown to provide a good fit for those subjects who either become sick or withdraw from the experiment within 2 h. The second part of the mixture accounts for those subjects who neither quit nor vomit within 2 h. The log-normal probability model is shown to give a poorer fit to the data and figures showing the relative fits of the estimated Weibull and log-normal distributions are provided. A nonparametric test is used to compare the five motion conditions of the Correlation Study. That test shows that there are significant differences in severity among the conditions.

Humans↗
PubMed1996

Motion sickness during off-vertical axis rotation: prediction by a model of sensory interactions and correlation with other forms of motion sickness.

Motion sickness (MS) susceptibility of 108 normal subjects was measured during off-vertical axis rotation (OVAR) as a function of angular velocity (60-180 degrees/s). The chair rotated about a longitudinal axis tilted 30 degrees with respect to gravity. For each velocity, we measured the duration of exposure necessary to evoke a moderate malaise, with a limit of 30 min. MS appeared the fastest at a rotation velocity of 105 degrees/s; higher or lower velocities were less provocative. These results are in good agreement with predictions made by Zupan et al. [in ICANN'94, Springer-Verlag, 1995] by means of a MS mathematical model derived from a model of sensory interactions [Droulez and Darlot, in Attention and Performance, Vol. 13, Lawrence Erlbaum, Hillsdale, 1989]. We also found that MS susceptibility during OVAR is positively correlated with susceptibility to other forms of MS. Since OVAR induces sensory messages very different from those induced by other provocative stimulations, this could suggest that the sensitivity of a common final vegetative locus is an important factor of the individual differences in susceptibility to MS.

Adult↗
PubMed2000

Finger motion, wrist motion and tendon travel as a function of keyboard angles.

OBJECTIVE: This study assessed the impact of keyboard angles (in terms of Pitch, Roll and Yaw) on tendon travel and wrist and finger joint kinematics for the flexor digitorum profundus and flexor digitorum superficialis.DESIGN. A repeated measures, laboratory study was conducted. Independent variables were three Pitch angles, three Roll angles, three Yaw angles, and three keyboard separation distances. Dependent variables were tendon travel, wrist deviation, wrist and finger joint kinematics, and Borg comfort rating. BACKGROUND: The increased usage of computers and the risk of cumulative trauma disorders have led to the development of alternate keyboards. This study is a biomechanical assessment of several keyboard designs.METHODS. Lightweight wrist and finger goniometers were used to measure motion of the wrist in three planes, and for three finger joints. Fifteen experienced typists (eight women, seven men) typed a standard text on 30 keyboard conditions. Regression equations were used to calculate tendon travel from joint positions. RESULTS: Tendon travel is sensitive to changes in Pitch, Roll and Yaw angles with approximately 13% difference between the minimal and maximal tendon travel. A flat keyboard produced more tendon travel than keyboards with greater Pitch and Roll angles.CONCLUSIONS. There is a trade-off between wrist and finger positions; as the wrist extends more, the finger joints flex more to compensate. Keyboards imposed different trade-offs between the wrist and finger positions, affecting the overall tendon travel. Relevance Alternate keyboard designs can significantly affect tendon travel and may address reduced repetitiveness in typing by reducing the amount of tendon travel.

Adult↗
PubMed2002

Medical prevention of space motion sickness--animal model of therapeutic effect of a new medicine on motion sickness.

Space motion sickness (MS) is one of the most important problems in the field of space medicine. In order to prevent space MS, a new medicine, PMPA, has been prepared by means of synthesizing in our laboratory. The purposes of this study were to set up animal models of PMPA against MS, and to observe its effects on anti-MS, and to prove its function of antagonism to choline. Eight cats, forty rabbits and two hundred and ten rats were selected as animal subjects. The parallel swing stimulus, a method causing the reversal syndromes and tests of anti-choline function were used in our experiments. The results are as follows: (1) The score of MS symptoms in cats with PMPA or scopolamine (SCOP) is significantly lower than that in cats with placebo (p<0.01), while the incidences of efficiency and prevention of PMPA (87.5%, 75%) are higher than those of SCOP (75.0%, 50%) in cats. (2) PMPA of 1.6 mg/kg or 0.8 mg/kg could antagonize the reversal syndromes and repress reversal rotation significantly in rabbits like SCOP in comparison with placebo (p<0.01). (3) PMPA could inhibit tremor evoked by oxotremorine or by nicotine-procaine in rats like SCOP, and play an important role in the antagonism to central M-choline and N-choline receptors. The animal experiments demonstrate that PMPA is an effective medicine against MS with antagonism function to choline.

Acceleration↗
PubMed1996

Rotation and radical motion thresholds support a two-stage model of differential-motion analysis.

Lower motion thresholds for rotational and radial flow have been measured for stimuli consisting of four closely packed circular apertures, each containing patches of drifting grating or plaid. Detection and direction thresholds were measured for gratings and plaids as a function of the relative orientation of the pattern components. There was a similarity between both types of threshold, supporting the existence of specialised rotation and radial-flow detectors. Further, thresholds increased with the relative component orientation for both gratings and plaids. This suggests that component information from a first stage, tuned spatiotemporally and to orientation, is being used directly to compute the optic flow in a two-stage process. A model based on this architecture is described by means of simple template receptive-field arrays with separable temporal and spatial tuning at the first stage.

Humans↗
PubMed2001

Features derived from first-order motion mechanisms predict anomalies in motion perception.

Current dominant hypotheses of how humans detect the movement of patterns assume that the pattern is divided into one-dimensional sinusoidally varying luminance patterns, referred to as gratings (first-order components). The speed of these gratings is independently encoded from predominantly spatial and temporal frequency information, and their direction is encoded from orientation information. This paper addresses the problem of how the individually encoded grating information is combined to give perceived pattern direction, given that real moving objects are generally made up of more than one component. More specifically, further evidence is presented for a combination based on the use of a feature derived from first-order components--'first-order feature hypothesis'. This hypothesis essentially implements a constraint on pattern direction called the intersection of constraints (IOC) proposed by Adelson and Movshon [1982, Nature 300 523-525]. A simulation of the model is used to make three new predictions about a perceived motion reversal reported by Derrington et al (1992, Vision Research 32 699-707); these predictions are tested and found to be consistent with the first-order feature hypothesis.

Computer Simulation↗
PubMed2006

Three-dimensional spatial modelling of the correlation between abdominal motion and lung tumour motion with breathing.

The aim of this research was to investigate whether a spatial correlation could be found between an external 3-D respiratory signal and the tumour trajectory. The respiratory signal was obtained by tracking the abdominal movement and the tumour trajectory was obtained by automatically determining the tumour position in a series of portal images. Three different models, based on Systems Identification, are presented to model the correlation using a 1-D respiratory signal, a 3-D respiratory signal and a 3-D respiratory signal together with previously determined tumour positions. Adequate correlation was found for all models in the direction of the tumour movement with standard deviations of 0.89 mm, 0.72 mm and 0.75 mm, respectively, and model fit of Rt2 = 0.19, 0.63 and 0.82, respectively. Increasing the frame rate for the acquisition of portal images from 3 to 15 frames per second improved the standard deviation and model fit. In summary, it is possible to spatially correlate a 3-D respiratory signal with the tumour trajectory using this approach. The models presented provide a framework that can be extended to include more information if required. A 3-D respiratory signal is preferable to a 1-D signal in modelling the tumour motion that is not along the main axis of tumour movement.

Abdomen↗
PubMed1983

Internal motion of F-actin in 10(-6)-10(-3) s time range studied by transient absorption anisotropy: detection of torsional motion.

By means of laser flash photolysis, the transient absorption anisotropy (TAA) of the triplet probe, 5-iodoacetamide-Eosin, labeling rabbit skeletal F-actin was measured in the 10(-6)-10(-3) s time range. The TAA curve at 20 degrees C showed a relatively slow decay phase covering several hundred microseconds and a large residual anisotropy (approximately 0.1 at 2 ms). After analysis with Barkley & Zimm's formula, it was concluded that the TAA of Eosin-F-actin can be approximated by the anisotropy decay due to torsional motion of F-actin.

Actins↗
PubMed2006

Comparison between aortic annulus motion and mitral annulus motion obtained using echocardiography.

Earlier studies have shown that the aortic root, in analogy with the mitral annulus, moves towards the left ventricular apex during systole. However, there are no earlier studies comparing the amplitude of the aortic annulus motion (AAM) with that of the mitral annulus (MAM), which was the main aim of the study. Another aim was to study the intra- and interobserver reproducibility (IIOR) of measuring AAM with M-mode and 2-D echocardiography as it is not obvious which of the methods that should be used. Twenty-one healthy subjects were examined by echocardiography. AAM and MAM were measured at different sites. IIOR was measured in 10 of the subjects. There was no significant difference between average AAM (15.3 +/- 1.5 mm) and average MAM (15.6 +/- 1.5 mm) and there was a rather good agreement between the variables. There was also no significant difference between AAM at the septal site (16.3 +/- 2 mm) and average MAM, but a significant difference between AAM at the lateral site (14.2 +/- 1.6 mm) and average MAM (P<0.001) and between the both sites of measuring AAM (P<0.001). The significant difference between the two sites of measuring AAM may have anatomical reasons but may also depend on difficulties in measuring AAM at the septal site where it has lower reproducibility than at the lateral site. IIOR of measuring AAM was good when using M-mode but poor when using 2-D echocardiography and AAM should preferably be measured using M-mode and not using 2-D echocardiography.

Adult↗
PubMed2006

Influence of visual motion on tactile motion perception.

Subjects were presented with pairs of tactile drifting sinusoids and made speed discrimination judgments. On some trials, a visual drifting sinusoid, which subjects were instructed to ignore, was presented simultaneously with one of the two tactile stimuli. When the visual and tactile gratings drifted in the same direction (i.e., from left to right), the visual distractors were found to increase the perceived speed of the tactile gratings. The effect of the visual distractors was proportional to their temporal frequency but not to their perceived speed. When the visual and tactile gratings drifted in opposite directions, the distracting effect of the visual distractors was either substantially reduced or, in some cases, reversed (i.e., the distractors slowed the perceived speed of the tactile gratings). This result suggests that the observed visual-tactile interaction is dependent on motion and not simply on the oscillations inherent in drifting sinusoids. Finally, we find that disrupting the temporal synchrony between the visual and tactile stimuli eliminates the distracting effect of the visual stimulus. We interpret this latter finding as evidence that the observed visual-tactile interaction operates at the sensory level and does not simply reflect a response bias.

Female↗
PubMed2003

Compound self-motion perception induced by two kinds of optical motion.

Two kinds of flow patterns consisting of random dots were presented simultaneously to subjects to investigate whether or not two kinds of vection occur simultaneously. One pattern induces vertical linear self-translation, whereas the other induces self-rotation around a vertical axis (when either pattern is presented alone). Three sets of conditions were tested. The first condition was one in which random dots moved in a summed direction of both flow vectors. In the second condition, both flow patterns were simply overlaid, whereas in the third condition, the two kinds of flow patterns were overlaid with a depth separation produced by binocular disparity. The subjects perceived both kinds of vection simultaneously in directions opposite to those of the corresponding flow components under the first condition, whereas either vection occurred mainly under the second condition. Under the third condition, both of the flows induced each kind of vection simultaneously, despite there being no physical vector summation of dot motion. The background flow induced vection in a direction opposite to the flow direction, whereas the foreground flow induced vection in the same direction as the flow direction. These results show that induced self-translation and induced self-rotation can occur simultaneously in two ways.

Humans↗