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Results for “Visualized analysis”

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At least 973 records · Page 54Linked to original sources

PubMed2006

Air-breathing rhythm in Clarias batrachus (Linn.): modulatory role of eyes, pineal and exogenous melatonin.

Effects of enucleation followed by pinealectomy and administration of exogenous melatonin on air-breathing activity rhythm in a fresh water catfish, C. batrachus maintained at LD 12:12 and laboratary temperature during its prepratory phase, were examined. Results of cosinor analysis clearly reveal that most of the intact individuals exhibited circadian rhythm in their air-breathing activity and such rhythm persists even after enucleation followed by pinealectomy and then melatonin administration. However, the period (tau) of the activity obtained by power spectrum analysis was prominent 24 hr in most of the intact individuals, but it was increased (tau > 24 hr) after enucleation in most of the individuals. In most of the enucleated + pinealectomized individuals tau was less than 24 hr, and after receiving melatonin treatment tau was shifted to prominent 24 hr in most of the individuals. In addition, visual analysis of the actograms depicted that in intact individuals air-breathing activity is entrained with the timings of lights on/off with elevation of activity during dark period and decreased activity during light hours. However, enucleated and enucleated + pinealectomized individuals showed free run in their activity rhythm. The treatment of melatonin reestablished the entrainment of activity at least with the timing of lights off, in most of the studied individuals. Further, daily mean of the air-breathing activity was decreased in enucleated + pinealectomized individuals as compared with other studied groups (intact, enucleated, enucleated + pinealectomized + melatonin receiving). It could be speculated that there may be existence of extraretinal and extrapineal photoreceptors in C. batrachus. However, eyes play an important role in regulating air-breathing activity rhythm in such species. In addition, exogenous melatonin may also have some modulatory effect on such rhythm.

Animals↗

PubMed1997

[Results of vitrectomy for macular packer after reattachment surgery for rhegmatogenous retinal detachment].

I analyzed the visual results in 184 eyes which had undergone vitrectomy and membrane peeling for macular pucker following treatment for rhegmatogenous retinal detachment. Patient age ranged from 9 to 83 (mean : 55) years, time between reattachment surgery and vitrectomy from 3 to 63 (mean : 15) months, and follow-up from 12 to 96 (mean : 39) months. For the analysis, visual acuity was examined 12 months after the last surgery in 93 pseudophakic eyes and 38 phakic eyes (patients age < 45) and 6 months in 53 phakic eyes (patient age > or = 45). When Y = log 1.5-log (postoperative acuity) and X = log 1.5-log (preoperative acuity), the regression line Y = 0.421 X (R2 = 0.765, p < 0.0001) was obtained. The regression line was Y = 0.395 X (R2 = 0.759, p < 0.0001) for pseudophakic eyes, and Y = 0.488 X (R2 = 0.777, p < 0.0001) for phakic eyes. Thus postoperative visual acuity was higher in pseudophakic eyes than in phakic eyes. When calculated from the pseudophakic line, mean postoperative acuity was 0.2 for preoperative acuity of 0.01, 0.5 for 0.1, and > 1.0 for > 0.5. Postoperative acuity was inversely correlated with the duration between reattachment surgery and vitrectomy (R2 = 0.544, p < 0.0001), and with the patient age (R2 = 0.0046, p = 0.0033). Better postoperative acuity, therefore, was associated with earlier vitrectomy.

Adolescent↗

PubMed2002

Consistency of echocardiographic ejection fraction: variation and 'drift' by interpreter and practice site.

AIMS: Visual analysis of ejection fraction by echocardiography (echo) is commonly performed, but little data exists regarding consistency among interpreters. We postulate that an active echo group evolves a standard to which interpreters cluster, with variation or 'drift' occurring at satellite sites distant from the main practice centre. Assuming that echo ejection fraction follows a normal distribution, average ejection fraction for high volume readers should be similar. METHODS AND RESULTS: From May 1997 to June 1999, 8187 echoes were read by 16 (average 512) readers of a single practice at several sites. Composite and individual ejection fraction (visual estimate) means and standard deviations were compared. Composite ejection fraction was 54.17+/-11.35. Mean ejection fraction varied significantly overall among readers (P<0.0001) with 37 comparisons between individual readers being significantly different (P<0.05). However, analysis suggested that these individual differences involved only five readers, four of whom practised at satellite sites. If these five readers were excluded, no significant individual differences were seen (n=6202). If only the four satellite readers were excluded, just four significant individual differences were seen (n=6915). CONCLUSIONS: (1) Within a busy single practice site, mean echo ejection fraction is very similar, suggesting a self-evolved practice standard that is consistently adhered to. (2) 'Drift' or variability is seen at smaller satellite sites, perhaps due to less exposure to the echo interpretations of others. (3) This type of analysis may provide a useful quality assurance tool for echo laboratories.

Cardiology↗

PubMed1999

[Analysis of neuropsychological disorders coupled with 99m Tc-HMPAO Spect in amyotrophic lateral sclerosis. Prospective study of 16 cases].

A prospective psychometric study was conducted in 16 patients who recently developed classic sporadic amyotrophic lateral sclerosis and had no signs of anxiety or depression. Tests included PM38, MMS, Rey word and Rey image tests, span, Stroop test, verbal fluency, Wisconsin test and London Tower test coupled with 99m Tc HMPAO tomography. Results demonstrated that the patients had no intellectual degradation nor visual constructive disorders but had disturbed verbal and visual memory with a reduced verbal fluency (particular bulbar forms), perseverance errors on the Wisconsin test (half of the cases) and an increased number of movements in the London Tower test. These disorders were moderate with no clinical impact and variable (the neuropsycological examination was normal in 4/16 patients). 99m Tc HMPAO tomography was normal in 4 cases, showed slight rolandic hypoperfusion in 6 and extensive hypoperfusion outside the motor zone in 2. Visual analysis of the 99m Tc HMPAO images did not reveal any clinico-metabolic correlations.

Adult↗

PubMed2004

Sleep disturbances in young subjects with visual dysfunction.

PURPOSE: To determine whether the type of ophthalmic disease is predictive of sleep and wakefulness disturbances in young subjects with visual dysfunction. DESIGN: Prospective cohort study. PARTICIPANTS AND CONTROLS: Twenty-five subjects (ages 12-20) were recruited from the Missouri School for the Blind. Twelve controls with normal sight were recruited from a residential school. METHODS: Daily activity was monitored for 14 days using wrist actigraphy. Sleep and wakefulness measures were derived from actigraphy records by automated analysis. Visually impaired subjects were prospectively stratified by presence or absence of optic nerve disease. MAIN OUTCOME MEASURES: Daytime napping and regularity of awakening time (wake-up time instability). RESULTS: Subjects with optic nerve disease napped in the daytime significantly more than other visually impaired children or normal sighted controls: 28.1+/-4.0 minutes per day (mean +/- standard error) versus 11.9+/-2.4 minutes per day in equally visually impaired subjects with intact optic nerve function versus 6.2+/-2.2 minutes per day in subjects with normal sight (P<0.0001). These subjects also showed significantly more variable awakening times than the other groups. Logistic regression revealed that subjects with optic nerve disease are 9.1 times more likely to demonstrate daily napping of more than 20 minutes per day than equally blind subjects without optic nerve disease (95% confidence interval [CI] = 1.4-58.7, P = 0.02). Blind subjects with optic nerve disease are 21.3 times more likely than children with normal sight to nap more than 20 minutes on average per day (95% CI = 1.2-378, P = 0.04). CONCLUSIONS: Optic nerve disease is predictive of increased daytime napping in young visually impaired subjects, suggesting that the nature and presence of ophthalmic disease affect the probability of concomitant sleep timing disorders.

Adolescent↗

PubMed1992

PROFILEGRAPH: an interactive graphical tool for protein sequence analysis.

The computer program PROFILEGRAPH, a graphical interactive tool for the analysis of amino acid sequences, is described. The main task of the program is to integrate a variety of sliding-window methods into a single user-friendly shell. The program allows the user to combine any amino acid specific parameter with a selection of several possible types of analysis and to plot the resulting graph in one of several windows on the screen. It is also possible to calculate the moment of the amino acid specific parameter for a given secondary structure and to display both the absolute moment value and the moment angle relative to a reference residue. Also included are several utilities that facilitate visual analysis of protein primary structures like, for example, helical-wheel diagrams. It is possible to adapt the majority of published sliding-window analysis procedures for use with PROFILEGRAPH.

Algorithms↗

PubMed1996

Computer classification of sleep in preterm and full-term neonates at similar postconceptional term ages.

A classification strategy of neonatal sleep is being developed by comparing visually scored minutes of 21 channels of electroencephalographic (EEG)/polygraphic recordings with the corresponding values for each physiological signal derived from either visual or computer analyses. Continuous 3-hour sleep studies on 54 preterm and full-term neonates at similar postconceptional term ages were acquired under environmentally controlled conditions using a computerized monitoring system. An on-line event marker program recorded behavioral observations. One of three EEG sleep states was assigned to each of 8,995 minutes by traditional visual analysis criteria. EEG spectral values, spectral and nonspectral cardiorespiratory calculations and behaviorally observed movements, arousals and rapid eye movement counts were submitted for discriminant analysis. Based on the total minutes known for each of three states (i.e. active, quiet and awake), linear combinations of all specified digitized parameters were formed into an arithmetic algorithm by use of discriminant analysis, which served as the basis of a state assignment for each minute. Fifty percent of the data were arbitrarily used as the training set to derive the state classification model. The remaining fifty percent of the data were used as the cross-validation "test sample" to determine the accuracy of the classification when compared to the visually analyzed score for each corresponding minute. Thirteen out of 32 physiological measures best predicted state of both preterm and full-term neonatal groups. For both groups, the correct classification for active sleep was 90.3%, quiet sleep was 97.4%, awake was 97% and the overall accuracy was 93.3%. However, the order of significance for specific variables differed between these two neonatal groups. Differences in the order of variables that predict sleep states between preterm and full-term infants may reflect adaptation of brain function of the preterm infant to prematurity and/or prolonged extrauterine experience.

Child, Preschool↗

PubMed1990

Does the brain know the physics of specular reflection?

Images of artificial and natural scenes typically contain many highlights generated by mirror-like reflection from glossy surfaces. Until recently, computational models of visual processes have tended to regard highlights as obscuring the structure of the underlying scene. The truth is that, on the contrary, highlights are rich in local geometric information. Here we report that the three-dimensional appearance of a highlight on a computer-simulated stereoscopic curved surface affects observers' judgment of surface gloss. We also show that the 3-D appearance of a highlight affects the perception of surface curvature--that is, it can force an ambiguous convex-concave figure to change state. We thus conclude that human visual analysis seems to employ a physical model of the interaction of light with curved surfaces, a model firmly based on ray optics and differential geometry.

Brain↗

PubMed1985

The effect of sulfinpyrazone on platelet deposition on Dacron vascular grafts in man.

To determine if sulfinpyrazone inhibits platelet deposition on chronically implanted (greater than 9 months) Dacron aortic bifurcation grafts in man, we performed indium-111 platelet imaging over 24 to 96 hours after labeled platelet injection in 10 males with grafts before and during sulfinpyrazone therapy (200 mg four times daily). Platelet accumulation was quantitated by a graft/blood ratio that compared indium-111 platelet image activity in the graft to platelet activity in well-counted whole blood. In addition, independent visual analysis compared platelet accumulation in the graft area to adjacent native arteries. By quantitative evaluation, sulfinpyrazone did not decrease the graft/blood ratio compared to baseline at 24 hours (3.2 +/- 0.4 vs 3.3 +/- 0.5, mean +/- SEM), 48 hours (4.6 +/- 0.6 vs 4.6 +/- 0.9) , 72 hours (6.8 +/- 0.8 vs 6.7 +/- 1.3), or 96 hours (9.7 +/- 1.6 vs 9.7 +/- 1.6) after labeled platelet injection. Visual interpretation also revealed no decrease in deposition in any patient during sulfinpyrazone therapy. We conclude that sulfinpyrazone does not inhibit platelet deposition on chronically implanted Dacron arterial graft surfaces in man. The techniques described provide a useful method of evaluating antithrombotic drug effects in patients with intravascular prosthetic materials.

Aged↗

PubMed1994

Identifying abnormal parathyroid glands in the thyroid uptake area using technetium-99m-sestamibi and factor analysis of dynamic structures.

UNLABELLED: A rapid (25 min) single tracer scintigraphic method to localize parathyroid gland abnormalities was evaluated in 24 patients with hyperparathyroidism. METHODS: Scintigraphy was performed with 99mTc-sestamibi prior to surgery. A 25-min dynamic series centered on the neck was acquired immediately after injection of 99mTc-MIBI. Two planar static views were obtained after 1 and 2 hr. To identify abnormal parathyroid tissue in the thyroid uptake area, a factor analysis of dynamic structure (FADS) was applied to the dynamic acquisition. The results were compared to the analysis of the two planar static views. RESULTS: FADS demonstrated abnormal uptake of the tracer in the thyroid area for 26 of the 31 parathyroid glands found to be abnormal at surgery (5/6 adenomas, 21/25 hyperplastic glands). In three cases, FADS demonstrated parathyroid uptake despite the absence of parathyroid tissue at surgery. FADS revealed as specific and more sensitive than the visual analysis of the two static views, since only 13/30 glands were still visible after 1 hr, and 5/26 after 2 hr. Furthermore, a study with two static views was found to be less sensitive for the detection of hyperplastic glands. CONCLUSION: FADS99mTc-MIBI is performed in less time than existing scintigraphic protocols. It is a promising method to detect abnormal parathyroid glands in the cervical area with a single tracer.

Adenoma↗

PubMed1991

Evaluation and clinical use of early washout ratio of thallium-201 in normal and ischemic myocardium after dipyridamole-induced vasodilation using ring-type emission computed tomography.

Using newly developed ring-type emission computed tomography (SPECT), we investigated the washout ratio (WR) of T1-201 in the myocardium quantitatively with fast dynamic scanning after infusion of dipyridamole (0.57 mg/kg), and assessed the feasibility of early WR as a marker to detect coronary artery disease. Twenty-three patients with and 8 patients without coronary artery disease had serial SPECT images obtained every 5 min for 45 min and at 180 min after dipyridamole and subsequent T1-201 injection. The best appropriate transaxial slice was selected for WR analysis. Most appropriate diagnostic time was 25 min after infusion of T1-201 (WR-25). Normal WR-25 was 7.1 +/- 4.0%, 5.9 +/- 3.1% and 7.1 +/- 2.3% at the septum, anterior and lateral wall, respectively. Sensitivity, specificity and accuracy to identify coronary stenosis greater than 50% with a usage of abnormal WR-25, defined as WR-25 less than (mean of normals--1SD) in each region of inferest of the left ventricle (LV), were 96%, 100% and 97%, respectively. These results were better than those achieved by visual analysis (sensitivity 78%, specificity 100%, accuracy 84%). In patients with single as well as multivessel disease, the regional accuracy in assessing stenosis of more than 50% in the left anterior descending artery (LAD) and left circumflex artery (LCX) by WR-25 was 94% and 83%, respectively, which was significantly better than using visual methods (LAD 72% and LCX 50%; p less than 0.05). Thus, evaluation of early washout ratios (WR-25) after dipyridamole injection is a valuable method to increase sensitivity in assessing regional myocardial perfusion abnormality and is helpful in detection of ischemic heart disease, even with multivessel disease.

Adult↗

PubMed2001

[Computer analysis of fetal heart rate by the Sonicaid Oxford 8002 System during pregnancy and labor. Personal experience and report of the literature].

Computer analysis of the fetal heart rate (FHR) was first described at Oxford University by the late Professor Dawes and by Redman for the prenatal surveillance of high risk pregnancies. We present our experience with this technique applied to the management of induced prematurity under 32 weeks' gestation in a tertiary perinatal center, by comparing our perinatal results with the preceding period of visual analysis of the FHR. Our analysis of the literature reports the results obtained with this technique in various high risk pregnancies and describes the modifications of computerised cardiotocography consecutive to obstetrical maneuvers or diverse maternal drug administrations. Finally we report our preliminary experience with the recently available Sonicaid Team IP System recommended for fetal monitoring during labor.

Female↗

PubMed2004

Selection of informative clusters from hierarchical cluster tree with gene classes.

BACKGROUND: A common clustering method in the analysis of gene expression data has been hierarchical clustering. Usually the analysis involves selection of clusters by cutting the tree at a suitable level and/or analysis of a sorted gene list that is obtained with the tree. Cutting of the hierarchical tree requires the selection of a suitable level and it results in the loss of information on the other level. Sorted gene lists depend on the sorting method of the joined clusters. Author proposes that the clusters should be selected using the gene classifications. RESULTS: This article presents a simple method for searching for clusters with the strongest enrichment of gene classes from a cluster tree. The clusters found are presented in the estimated order of importance. The method is demonstrated with a yeast gene expression data set and with two database classifications. The obtained clusters demonstrated a very strong enrichment of functional classes. The obtained clusters are also able to present similar gene groups to those that were observed from the data set in the original analysis and also many gene groups that were not reported in the original analysis. Visualization of the results on top of a cluster tree shows that the method finds informative clusters from several levels of the cluster tree and indicates that the clusters found could not have been obtained by simply cutting the cluster tree. Results were also used in the comparison of cluster trees from different clustering methods. CONCLUSION: The presented method should facilitate the exploratory analysis of big data sets when the associated categorical data is available.

Cluster Analysis↗

PubMed1997

An independent software system for the analysis of dynamic MR images.

PURPOSE: A computer system for the manual, semi-automatic, and automatic analysis of dynamic MR images was to be developed on UNIX and personal computer platforms. The system was to offer an integrated and standardized way of performing both image processing and analysis that was independent of the MR unit used. MATERIAL AND METHODS: The system consists of modules that are easily adaptable to special needs. Data from MR units or other diagnostic imaging equipment in techniques such as CT, ultrasonography, or nuclear medicine can be processed through the ACR-NEMA/DICOM standard file formats. A full set of functions is available, among them cine-loop visual analysis, and generation of time-intensity curves. Parameters such as cross-correlation coefficients, area under the curve, peak/maximum intensity, wash-in and wash-out slopes, time to peak, and relative signal intensity/contrast enhancement can be calculated. Other parameters can be extracted by fitting functions like the gamma-variate function. Region-of-interest data and parametric values can easily be exported. RESULTS AND CONCLUSION: The system has been successfully tested in animal and patient examinations.

Algorithms↗

PubMed2006

The Pathway Tools cellular overview diagram and Omics Viewer.

The Pathway Tools cellular overview diagram is a visual representation of the biochemical network of an organism. The overview is automatically created from a Pathway/Genome Database describing that organism. The cellular overview includes metabolic, transport and signaling pathways, and other membrane and periplasmic proteins. Pathway Tools supports interrogation and exploration of cellular biochemical networks through the overview diagram. Furthermore, a software component called the Omics Viewer provides visual analysis of whole-organism datasets using the overview diagram as an organizing framework. For example, gene expression and metabolomics measurements, alone or in combination, can be painted onto the overview, as can computed whole-organism datasets, such as predicted reaction-flux values. The cellular overview and Omics Viewer provide a mechanism whereby biologists can apply the pattern-recognition capabilities of the human visual system to analyze large-scale datasets in a biologically meaningful context. SRI's BioCyc.org website provides overview diagrams for more than 200 organisms. This article describes enhancements to the overview made since a 1999 publication, including the automatic layout capability, expansion of the cellular machinery that it includes, new semantic zooming and poster-generating capabilities, and extension of the Omics Viewer to support painting of metabolites, animations and zooming to individual pathway diagrams.

Computer Graphics↗

PubMed1987

[Inorganic pyrophosphatase--a new enzyme label for biochemical analysis].

Inorganic pyrophosphatase isolated from Escherichia coli has been proposed as a label in heterogeneous enzyme immunoassays. The enzyme is remarkably stable and insensitive to sodium azide. Enzyme-antibody conjugates were prepared with glutaraldehyde and purified by gel filtration. Enzyme activity was measured by means of a sensitive colour reaction between phosphomolybdate and malachite green. A 5-10-fold increase is sensitivity in terms of absorbance readings was observed compared to peroxidase-based assays. The colour change (yellow/greenish blue) inherent in the use of pyrophosphatase as the labelling agent is highly suitable for visual analysis.

Enzyme Stability↗

PubMed1997

Simultaneous spike detection and topographic classification in pediatric surface EEGs.

In this study, an algorithm is introduced for the automatic detection and simultaneous topographic classification of interictal regional spike activity in pediatric surface EEG records. The algorithm is based on the classification of the topographic distribution of instantaneous power by means of a 'group' trained classifier. The results of automatic spike analysis were compared with the decisions of two experienced electroencephalographers. Four routine EEG records exhibiting (multi)regional spikes were examined. The mean selectivity for the automatic spike detector was 84.6% (mean sensitivity 88.1%, mean specificity 89.3%) and for the electroencephalographers 85.3%. All spikes detected by the algorithm were simultaneously classified according to their topographic characteristics. The results of automatic spike classification (lateralization/localization) corresponded to the results of visual analysis.

Algorithms↗

PubMed2003

Gray-scale liver enhancement with Sonazoid (NC100100), a novel ultrasound contrast agent; detection of hepatic tumors in a rabbit model.

The liver contrast effects of Sonazoid in two ultrasonographic imaging modes, gray-scale conventional and harmonic, were examined as a time-related study in normal rabbits, and evaluated quantitatively and visually with tumor-model rabbits to estimate the diagnostic potential. Peak enhancement of vessels and parenchyma was observed 1 min after injection in both modes, although signal enhancement in the parenchyma lasted for 120 min compared with rapid decay (5-10 min) in vessels. When Sonazoid was intravenously injected into metastatic carcinoma-model (VX-2) rabbits, all hepatic tumors showed ring enhancement in the early phase followed by clear contrast defects in the delayed phase, because signal enhancement remained only in normal parenchyma. Visual analysis scores for the diagnosis of tumors were improved by Sonazoid injection, and the videodensitometric differences between tumor and normal tissues were significantly greater after injection. Although the harmonic mode tended to show better contrast effects, the conventional mode provided significant contrast enhancement in this hepatic tumor-model. Sonazoid might be useful for the detection of undifferentiated tumors in the liver by making it possible to visualize neovascularity in the early phase and clear contrast defects in the delayed phase, not only in the harmonic but also in the conventional mode.

Animals↗