PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “tracking methods”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 127 records · Page 7Linked to original sources
PubMed1989

MR angiography and dynamic flow evaluation of the portal venous system.

We studied the value of MR angiographic techniques in imaging the portal venous system. Projection angiograms were created by postprocessing a series of two-dimensional, flow-compensated gradient-echo images. Flow velocity was determined by a bolus-tracking method with radiofrequency tagging and multiple data readout periods. Each image was acquired during a breath-hold. MR angiography was applied to six normal subjects and four patients with abnormal hemodynamics in the portal venous system. Flow velocity determined by MR was correlated with the results of duplex sonography. The main portal vein and intrahepatic branches were shown in all cases. Portosystemic collaterals were identified in all patients with portal hypertension. In normal subjects, peak flow velocities (17.9 +/- 2.8 cm/sec) on MR correlated well with values determined by duplex sonography (17.5 +/- 2.2 cm/sec) (r = .846, p less than .04). Reversed portal blood flow was shown in two patients. One patient with portal vein thrombosis had no evidence of flow by MR angiography. Our results indicate that MR angiography can provide a three-dimensional display of normal and abnormal vascular anatomy as well as functional information in the portal venous system.

Blood Flow Velocity↗
PubMed1982

Uranium content in porcelain denture teeth and in porcelain powders for ceramic crowns.

Some porcelain denture teeth and porcelain powders marketed in Sweden haven been analyzed for the content of uranium. The fission track method and the delayed neutron technique were the methods used. Compared to results published previously the content of uranium was generally found to be lower in the brands analyzed. The denture teeth contained 23-186 ppm for Anatoform, 35-137 ppm for Myerson, 15-45 ppm for Candulor G and 20-53 ppm for Vivopearl. The baked and fired porcelain powders showed values of about 2.8 ppm at most, those in the form of powder about 25 ppm at most. The radiation dose to the mucosa of the upper lip was calculated and is discussed.

Crowns↗
PubMed1986

Concentration and particle-size distribution of uranium and some trace elements in airborne dust collected in Tsukuba.

Uranium and some other trace elements were determined in the size-separated airborne dust collected in Tsukuba with an Andersen-type high-volume cascade impactor. The fission track method and the instrumental neutron activation method were applied to the determination of uranium and other elements, respectively. Selenium, antimony, arsenic and zinc were found to be rich in particulates of smaller size, while scandium, iron and cobalt showed a reverse trend, depending on their main origins, i.e. whether industrial or terrestrial. Uranium was distributed in both the larger and smaller particles to the same extent, suggesting that it is derived from both the terrestrial and artificial sources.

Dust↗
PubMed1987

Distribution of uranium in human lungs.

Several human lung samples were dissected into lobes and uranium and silicon contents in each lobe were determined by the fission track method and the inductively coupled plasma-atomic emission spectrometry (ICP-AES), respectively. It was found that both uranium and silicon concentrations were high in the upper lobe compared with those in the lower one. Though the tendency may be mainly interpreted by the deposition way of airborne dust in the lung, the higher U/Si concentration ratio in the upper part than that in the lower part of lungs may suggest the partial removal of uranium deposited in the lower part of the tissue.

Air Pollution, Radioactive↗
PubMed1987

Distribution of uranium in human bones.

Uranium and calcium contents in human bones (skull, rib and femur) were determined by the fission track method and the inductively coupled plasma-atomic emission spectroscopic method (ICP-AES), respectively. The U/Ca concentration ratio in the bones was found to decrease in the order of rib greater than femur greater than skull, which is in accordance with the decreasing order of the mean annual replacement percentage of bone components. Several femur bones were cut into several longitudinal segments, and uranium and calcium contents in each segment were determined. Among these, the U/Ca ratio in the epiphysis was higher than those in the diaphysis.

Adult↗
PubMed1987

Plutonium and uranium in Japanese human tissues.

Plutonium and uranium in human tissues obtained from residents of the Tokyo area were determined by a-spectrometry and the fission track method, respectively. The distribution pattern of each element was estimated on the basis of mean concentration obtained. Plutonium is concentrated in some special organs, while uranium is distributed rather generally throughout the whole body. This difference of distribution tendency is considered to be due to the characteristics of stable chemical states of the elements in body fluid; Pu4+ for plutonium and UO2(2+) for uranium.

Asian People↗
PubMedDate not supplied

Biocybernetic investigations of pursuit and posture motor control--a strategy for a detailed characterization of movement disorders in brain-damaged children.

By means of a biocybernetic approach the pursuit and posture motor control of brain-damaged children with spastic hemiparesis and disturbed motor coordination of mild extent were investigated. The postural motor control system was loaded by pseudostochastic binary torque sequences applied to the wrist. The dynamics of this system were characterized on the basis of the parameters forearm displacement as well as surface-EMG of M. Biceps and Triceps (calculations of weight functions). The pursuit motor control was analyzed by a pursuit tracking method. By this way the motor capacity for fine and rough motor coordination, motor rhythm, motor adaptation, the maximal speed of movements and motor reaction time could be tested. Considering these results a characterization of movement control on different levels of motor regulation was possible (dynamics of muscular, spinal, and supraspinal components of motor control).

Brain Damage, Chronic↗
PubMed1989

[Analysis of oculomotor disorders in motor neuron disease].

Oculomotor disorders have been considered to be one of the negative symptoms in motor neuron disease (MND). However, recently, ophthalmoplegia, abnormal Bell's phenomenon and disturbance of pursuit movement have been reported. We tried to evaluate 32 patients with MND (19 males and 13 females; age, 35 to 77 years; 52.4 +/- 10.1 years) by bedside examination and electro-oculography (EOG) using an eye tracking method. Twenty-three of them were classified as amyotrophic lateral sclerosis (ALS) and seven as bulbospinal muscular atrophy, and two were unclassified. One hundred healthy persons for bedside examination and twenty-two for EOG were investigated as controls. Findings by bedside examinations were as follows; 1) Slight limitations of upward only, up & downward and upward & horizontal gaze were observed in 5 cases (15.6%), 1 case (3.1%) and 1 case (3.1%), respectively. 2) Incomplete convergence was observed in 11 cases. (34.4%) 3) Horizontal gaze nystagmus was observed in 6 cases. (18.8%) 4) As regards the frequency of limitation of upward gaze and incomplete convergence, there were no statistically significant differences from those in controls. Electrooculographic results were: 1) square wave jerks (SWJs) were recorded in 3 cases. (9.4%) 2) Amplitude ratio of saccade was significantly higher in MND than that in controls with the risk less than 0.1%. 3) The degree of ocular dysmetria was significantly higher in MND than that in controls with the risk less than 0.5%. These abnormalities were not directly related to suffering period. Although the mechanism is not known, several reports of the effectiveness of thyrotropin releasing hormone (TRH) in ALS were recently published.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

[Ocular motor abnormalities in progressive supranuclear palsy].

Eleven patients, 7 males and 4 females, of progressive supranuclear palsy (PSP) were examined neuro-otologically for the purpose of elucidating the characteristics of ocular motor abnormalities. All cases were admitted to our hospital and age at onset was from 52 to 71 years old, duration of illness was 2 to 11 years. Range of voluntary eye movements and abnormal eye movements including nystagmus were examined on naked eyes and with electronystagmography (ENG). Smooth pursuit movements and saccadic eye movements were tested both horizontally and vertically by using visual tracking method with ENG recordings. Optokinetic nystagmus test and caloric test with visual suppression test were also performed. These neurotological examinations were made repetitively in 5 cases and their progressions were observed. Vertical gaze palsy and convergence palsy were observed in all cases as the initial symptom. In this study downward gaze was more severely disturbed than upward gaze. Using ENG, saccadic eye movements (saccades) were disturbed earlier than smooth pursuit movements. Hypometric saccades and decreased saccadic velocity were common abnormalities. In the later stage of the disease, horizontal eye movements were also disturbed. In four cases bilateral adduction palsy was added to vertical gaze paralysis so that the lesion of the MLF to oculomotor nucleus was suggested to exist. These voluntary eye movements were worsened gradually as the disease progressed. By using ENG we could find so called abnormal eye movements more frequently than the previous reports. Eight patients demonstrated horizontal gaze nystagmus, and rebound nystagmus were observed in four cases.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1986

[Organization of the median and intralaminar nuclei of the thalamus: hypotheses on their role in the onset of certain central pain].

Afferent neurons from thalamic median and intralaminar (IL) nuclei arise in the spinal cord, brain stem synapses, substantia nigra, internal pallidum and cerebral cortex, directly and through the intermediary of the reticular nucleus of the thalamus (RT). Efferent neurons terminate in the anterior thalamic nuclei, RT, striatum and cerebral cortex. Tracking methods in the rat have demonstrated that some RT neurons which project towards the IL are surrounded by endings from the posterior ventral nucleus (VP). Electrical stimulation of multiple prosencephalic structures (mainly VP) and of sensory pathways induce responses in IL of brief latency followed by inhibition. Whereas the responses appear to be related to activation of excitatory projections (under the tonic facilitating control of cerebral cortex) the inhibition phases could be related to activation of RT, since they disappear after lesion of the RT. This nucleus could act as a common final pathway of inhibitions exerted on IL in the rat. Studies in this species have demonstrated that a lateral lesion of the thalamus that includes the RT provokes the appearance in IL of abnormal neuronal hyperactivity of a tonic nature and yet still exaggerated by stimuli normally capable of inducing responses of brief duration followed by inhibition. Human studies using a tomoscintigraphic method to determine regional blood flow have shown "hyperactivity" of the thalamic region in patients with pain of central origin during a natural stimulus provoking hyperpathia. This was not observed during painful states without hyperpathia. The working hypothesis proposed is that of a central lesion inducing a hyperpathia provoking pathologic hyperactivity in certain thalamic nuclei.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Vibratory perception threshold in the lower extremities. Normative values.

Objective was to obtain normative values for the vibratory perception threshold (VPT) in the lower extremities and study the dependence of VPT on various physiological factors. Thirty healthy volunteers: 10 men and 20 women entered in the study. The VPT for 8, 16, 31.5, 63, 125, and 500 Hz were estimated on the right and left external malleolus using the B&K vibration threshold meter, modified type 1800, and the threshold tracking method. The applied static force could not be controlled. The measurements were repeated twice. VPTs expressed as mean +/- SD were as follows: 8 Hz 109 +/- 3.4 dB, 16 Hz 112 +/- 4.1 dB, 31.5 Hz 116 +/- 6.2 dB, 63 Hz 116 +/- 8.4 dB, 125 Hz 117 +/- 8 dB, 250 Hz 125 +/- 9.3 dB, and 500 Hz 136 +/- 13.1 dB. A nomogram was constructed with reference ranges of VPTs for individual frequencies, from which the profile of vibratory perception thresholds can be seen. Moreover, a global index was calculated as a sum of VPTs for individual frequencies. Its reference value was 840 +/- 52 dB and it varied in repeated measurements by up to 9%. No statistically significant difference of VPTs between the right and left side and between the 1st and 2nd examination was found. A tendency to the increase of VPTs with age was observed, which in males reached statistical significance for frequencies 16, 31.5, 63, and 125 Hz.

Adolescent↗
PubMed1994

[Bathing a patient with cancer pain treated with continuous epidural blockade--subcutaneous catheter track and Lapack method].

Continuous epidural blockade is considered to be the most useful device for the management of cancer pain. However, it has the disadvantage to compel the patients to restrict their daily activities. We report a unique "Subcutaneous catheter track & Lapack-method" that enabled a patient with epidural catheter to safely bath at home. A 56-year-old male with a local recurrence of rectal cancer was suffering from perineal pain, which was well controlled by oral and epidural morphine. Since his wishing was to bath, we made a long subcutaneous catheter track with Tuohy-needle to prevent infection, and let him bath with transparent film dressings (Bioclusive) and Lapack to tightly cover and seal up the catheter. Although subcutaneous pustule occurred 7 days after the beginning of bathing, it was easily cured by local disinfection. He was able to enjoy bathing without any infection with this method at home for about 2 months after discharge, until he returned to the hospital. "Subcutaneous catheter track & Lapack-method" offers a safe and comfortable bathing to patients with epidural catheter, and contributes to the improvement of their quality of life.

Analgesia, Epidural↗
PubMed1991

Orientation in birds. Satellite tracking: a new method in orientation research.

The study of bird migration by satellite tracking began in the 1980s, after transmitters had become sufficiently small to allow the monitoring of larger migrating species. The initial studies in this direction were all successful with respect to establishing this method (Section 2) of elucidating new migration patterns and various aspects of orientation. These pilot studies are summarized in Section 3, Table 1, Figures 1-4. We believe that studies on avian orientation and navigation will, in general, greatly benefit from satellite tracking if some prerequisites are fulfilled and adequate experiments planned (Section 4). In future studies, smaller transmitters with increased life expectancies are needed, and possible effects of these transmitters on bird behaviour must be examined. Considerable improvement of satellite tracking in avian orientation research is to be expected, along with the development of a new generation of satellites allowing communication between satellites and transmitters (Sections 4, 5).

Animals↗
PubMed1993

Mechanisms of adoptive immunotherapy: improved methods for in vivo tracking of tumor-infiltrating lymphocytes and lymphokine-activated killer cells.

Adoptive immunotherapy with tumor-infiltrating lymphocytes (TIL) and lymphokine-activated killer cells has been demonstrated to mediate regression of tumors in murine models and in selected patients with advanced cancer. Improved methods for monitoring immune cell traffic, particularly to sites of tumor, are needed to elucidate mechanisms of antitumor activity and optimize treatment protocols. Traditional cell tracking methods such as fluorescent protein labeling and radiolabeling using 111In, 125I, or 51Cr are limited by isotope half-life, leakage or transfer of label from immune cells, and toxicity or altered cell function caused by the labeling process. Labeling with genetic markers allows long-term cell tracking but is laborious to perform and difficult to quantitate. We have used two recently described lipophilic cell tracking compounds (PKH26 and 125I-PKH95) which stably partition into lipid regions of the cell membrane to track immune cells in vivo. Concentrations of each tracking compound which had no adverse effects were determined for a variety of murine TIL and lymphokine-activated killer cell functions. Viability was unimpaired at labeling concentrations of up to 5 microM for PKH95 and 20 microM for PKH26. TIL proliferation was unaltered by labeling with up to 5 microM PKH95, 20 microM PKH26, or a combination of 15 microM PKH26 and 5 microM PKH95. In vivo cytotoxic effector function and in vivo therapeutic efficacy of lymphokine-activated killer cells and TIL were also unimpaired by labeling with 20 microM PKH26 or 1 microM 125I-PKH95. Subsequent studies in an adoptive transfer immunotherapy model used 125I-PKH95 to track the biodistribution of TIL in tumor and in non-tumor-bearing animals and PKH26 fluorescence to monitor microdistribution within tissues and distinguish TIL from host T-cells. The results suggest that differential accumulation, selective retention, or proliferation at the tumor site cannot account for the observed pattern of therapeutic efficacy. We hypothesize that a minimum number of TIL must reach the tumor site in order to achieve a demonstrable therapeutic effect.

Animals↗
PubMed1996

[New method for automatic tracking of the endocardial boundary in clinical use].

This study attempted to detect the left ventricular endocardial boundary in six healthy men (volunteers) using a newly developed computerized two-dimensional echocardiography method. Automatic detection of the left ventricular endocardium was achieved by; sampling of pictures, noise reduction of the pictures, filtering, decision of the early loop, detection of the left ventricular endocardial boundary, smoothing the boundary, and correction of the boundary. This process requires only 2-3 sec. Areas of the short-axis cross-sections in systolic and diastolic phases of one cardiac cycle were obtained and the percent change rate of these areas on a cardiac cycle were calculated. These were compared with the results obtained by the manual method. The boundary of the left ventricular endocardium detected by the computerized method almost coincided with that found by the manual method. Areas and the change rates obtained were correlated with those by the manual method (areas: r = 0.86, % change rate of area: r = 0.94). This new method is suitable for clinical use.

Adult↗
PubMed1980

The hemodynamic tracking system: a method of data management and guide for cardiovascular therapy.

In the operating room or intensive care unit, multiple measurements of circulatory function are almost mandatory in patients with significant cardiovascular disease. Use in these areas requires that the information must be easily organized, rapidly obtained, and inexpensive. A hemodynamic tracking system that meets these criteria is described. This system incorporates a hand-held programmable calculator (cost = $210 to $300) to derive variables computed from standard cardiovascular measurements. The time required to obtain a set of measurements (including thermodilution cardiac output determinations in duplicate), key the numbers into the calculator, and obtain the derived indices is 4 minutes. Two patients, who had acute mitral insufficiency and whose clinical management differed substantially are presented to illustrate the use of data obtained from the hemodynamic tracking system.

Aged↗
PubMed1997

The effects of salmeterol on power output in nonasthmatic athletes.

BACKGROUND: Salmeterol xinafoate is a new aerosol inhalant that is used in the treatment of asthma. It is currently banned by the International Olympic Committee because of the concern that it may lend an unfair competitive advantage to the user. OBJECTIVE: The purpose of this study was to determine whether salmeterol improves short-term anaerobic performance in elite nonasthmatic track cyclists. METHODS: Eleven elite track cyclists volunteered to perform a 30-second all-out cycle ergometer test 3 hours after receiving either 42 micrograms of salmeterol xinafoate or placebo applied in a double-blind crossover procedure. During the ergometer test, peak power output, total work, time to peak power, and percent fatigue (decline in power output) were measured. Pulmonary measurements were also taken before and at various time points after inhalation and the ergometer test. A methacholine challenge was administered to each subject before participation in the study to ensure that none of the subjects had any reactive airway diseases. RESULTS: There were no significant differences (p > 0.05) between the placebo and salmeterol trials for peak power output, total work performed during the 30-second test, percent fatigue, and time to peak power. No differences between trials were observed for the pulmonary function test variables at any of the time points. Blood lactate concentrations before and after administration of drug or placebo were also not significantly different between trials. Additionally, salmeterol did not affect the maximal heart rate achieved during the test as compared with the placebo. CONCLUSIONS: Short-term salmeterol use within the prescribed dosage was not shown to increase short-term power output in nonasthmatic cyclists.

Adult↗