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At least 703 records · Page 39Linked to original sources

PubMed1976

[Impulse cytophotometry in neoplasm prevention. The behavior of normal vaginal smears in the impulse cytophotometric histogram].

Evaluation of histograms of normal cervical and vaginal smears, produced by ""rapid flow through'' cytophotometry. Normal cytological cervical and vaginal smears were examined for their appearance in histograms in order to find criteria for the classification of ""normal non-pathological'' cytological slides. Simultaneously, the reliability of the standardized method for preparation of vaginal and cervical smears was checked. The diagrams and data produced by the histograph were also coded on line and analyzed by a computer; thus obtaining an objective mathematical analysis and avoiding errors due to subjective visual analysis of the histograms. The objective interpretation of histograms of normal vaginal smears is an important step to the realisation of automatic pre-screening.

Computers↗

PubMedDate not supplied

A visual fuzzy cluster system for patient analysis.

A visual fuzzy cluster (VFC) system is developed to assist physicians in interactively detecting and refining cluster partitions for patients with acute upper respiratory infections. The VFC system assists physicians in discovering relationships among patients by applying a fuzzy cluster algorithm to analyse a case base of patient findings. The algorithm discovers similarities among patients, while at the same time identifying atypical patients. The system visually presents the fuzzy cluster solutions on a three-dimensional animated display. Physicians then interactively manipulate icons representing patients to explore and refine the fuzzy cluster solution. Initial experiences with the VFC prototype are encouraging and support the claims that the system improves physician understanding and allows physicians to take advantage of visual recognition and manipulation skills to define and label patient groupings. The resulting labels and cluster centres or prototypes offer insight into the set of patient features that best discriminate between groups.

Algorithms↗

PubMed1986

Scintigraphic phase analysis of left anterior hemiblock.

Left anterior hemiblock (LAHB) is a relatively common disturbance of ventricular conduction which can be an indicator of early conduction system disease. In an effort to better understand this condition, phase analysis of resting radionuclide ventriculograms (RVG) was used to evaluate five patients with LAHB and six normal patients with particular reference to the phase angle difference between the septum and the postero-lateral wall. All patients had normal ejection fractions and visually normal wall motion on RVG. Visual analysis of phase images showed significant differences between the LAHB and normal patients' LV contraction synergy (p less than 0.03) with a delay in septal contraction versus the postero-lateral wall. Four of five patients with LAHB were outside 2 standard deviations of the normal range. Regional quantitative analysis of phase angle differences between posterolateral and septal walls tended to show this difference between normals and LAHB (p = 0.08) as well. Three of five patients with LAHB were outside 2 standard deviations from the normals' mean. There were no significant differences between the standard deviations, skewness, or kurtoses of phase angle histograms of LAHB versus normal patients. Phase analysis can identify some patients with LAHB by both visual and quantitative analysis. The ability to detect and possibly quantitate subtle conduction abnormalities such as LAHB may result in a better understanding of such conduction system diseases.

Electrocardiography↗

PubMed1988

[Treadmill exercise echocardiography: quantitative analysis of regional left ventricular wall motion by computer graphics].

To detect significant coronary lesions based on exercise-induced reversible asynergy, two-dimensional echocardiograms were recorded before and immediately after treadmill exercise test in 15 patients with angina pectoris (AP) and six patients with neurocirculatory asthenia (NCA). Short-axis views of the left ventricle were analyzed quantitatively, using the following indices: segmental area change (%A); segmental wall thickness change (%Th); and relative curvature (rC) which was the product of curvature of each segment multiplied by end-diastolic circumference. The results were compared with those of coronary angiography, T1-201 myocardial emission computed tomography, and exercise electrocardiography. 1. The results of comparisons of quantitative analysis by %A, %Th, and rC with qualitative (visual) analysis were as follows: the sensitivities were 57%, 74% and 91%; the specificities were 75%, 75% and 90%; and the accuracies were 68%, 75% and 90%, respectively. 2. To detect coronary stenosis of more than 75%, visual assessments and assessments by rC were superior to assessments by %Th or %A. The accuracies were 93%, 91%, 73% and 61%, respectively. 3. In five cases with three-vessel disease, all diseased coronary arteries were detected by treadmill exercise echocardiography using rC as an index. However, by treadmill exercise T1-201 myocardial emission computed tomography, the diagnosis of three-vessel disease was possible in only one case. 4. The results of treadmill exercise electrocardiography were positive in 11 of 15 the AP patients and in all six NCA patients. The results of exercise echocardiography using rC as an index were normal in all NCA patients and abnormal in 14 of the 15 AP patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1994

Quantitative analysis of EMG interference pattern in patients with laryngeal paresis.

Conventional (visual) analysis of EMG was compared to a computerized quantitative method (turns/amplitude). Ten patients with a clinical history of peripheral nerve lesion were examined in order to investigate whether quantitative analysis of EMG increased the diagnostic sensitivity of peripheral nerve lesions to the laryngeal muscles. Quantitative analysis either agreed with conventional analysis or resulted in false negative diagnosis compared to conventional analysis. Thus, conventional analysis turned out to be more sensitive to neurogenic damage than the quantitative method. EMG results were compared to clinical findings.

Adult↗

PubMed2003

Statistical and visual morph movie analysis of crystallographic mutant selection bias in protein mutation resource data.

The relationship between protein mutations and conformational change can potentially decipher the language relating sequence to structure. Elsewhere, we presented the Protein Mutant Resource (PMR), an online tool that systematically identified related mutants in the Protein DataBank (PDB), inferred mutant Gene Ontology classifications using data-mining, and allowed intuitive exploration of relationships between mutant structures. Here, we perform a comprehensive statistical analysis of PMR mutants. Although the PMR contains spectacular conformational changes, generally there is a counter-intuitive inverse relationship between conformational change and the number of mutations. That is, PDB mutations contrast naturally evolved mutations. We compare the frequencies of mutations in the PMR/PDB datasets against the PAM250 natural mutation frequencies to confirm this. We make available morph movies from PMR structure pairs, allowing visual analysis of conformational change and the ability to distinguish visually between conformational change due to motions (e.g., ligand binding)and mutations. The PMR is at http://pmr.sdsc.edu.

Bias↗

PubMed2024

Recent advances in environmental antibiotic resistance genes detection and research focus: From genes to ecosystems.

Antibiotic resistance genes (ARGs) persistence and potential harm have become more widely recognized in the environment due to its fast-paced research. However, the bibliometric review on the detection, research hotspot, and development trend of environmental ARGs has not been widely conducted. It is essential to provide a comprehensive overview of the last 30 years of research on environmental ARGs to clarify the changes in the research landscape and ascertain future prospects. This study presents a visualized analysis of data from the Web of Science to enhance our understanding of ARGs. The findings indicate that solid-phase extraction provides a reliable method for extracting ARG. Technological advancements in commercial kits and microfluidics have facilitated the efficacy of ARGs extraction with significantly reducing processing times. PCR and its derivatives, DNA sequencing, and multi-omics technology are the prevalent methodologies for ARGs detection, enabling the expansion of ARG research from individual strains to more intricate microbial communities in the environment. Furthermore, due to the development of combination, hybridization and mass spectrometer technologies, considerable advancements have been achieved in terms of sensitivity and accuracy as well as lowering the cost of ARGs detection. Currently, high-frequency terms such as "Antibiotic Resistance, Antibiotics, and Metagenomics" are the center of attention for study in this area. Prominent topics include the investigation of anthropogenic impacts on environmental resistance, as well as the dynamics of migration, dissemination, and adaptation of environmental ARGs, etc. The research on environmental ARGs has made significant advancements in the fields of "Microbiology" and "Biotechnology Applied Microbiology". Over the past decade, there has been a notable increase in the fields of "Environmental Sciences Ecology" and "Engineering" with a similar growth trend observed in "Water Resources". These three domains are expected to continue driving extensive study within the realm of environmental ARGs.

Drug Resistance, Microbial↗

PubMed2005

Transsaccadic integration of visual features in a line intersection task.

Transsaccadic integration (TSI) refers to the perceptual integration of visual information collected across separate gaze fixations. Current theories of TSI disagree on whether it relies solely on visual algorithms or also uses extra-retinal signals. We designed a task in which subjects had to rely on internal oculomotor signals to synthesize remembered stimulus features presented within separate fixations. Using a mouse-controlled pointer, subjects estimated the intersection point of two successively presented bars, in the dark, under two conditions: Saccade task (bars viewed in separate fixations) and Fixation task (bars viewed in one fixation). Small, but systematic biases were observed in both intersection tasks, including position-dependent vertical undershoots and order-dependent horizontal biases. However, the magnitude of these errors was statistically indistinguishable in the Saccade and Fixation tasks. Moreover, part of the errors in the Saccade task were dependent on saccade metrics, showing that egocentric oculomotor signals were used to fuse remembered location and orientation features across saccades. We hypothesize that these extra-retinal signals are normally used to reduce the computational load of calculating visual correspondence between fixations. We further hypothesize that TSI may be implemented within dynamically updated recurrent feedback loops that interconnect a common eye-centered map in occipital cortex with both the "dorsal" and "ventral" streams of visual analysis.

Adult↗

PubMed1999

Automatic estimation of the correlation dimension for the analysis of electrocardiograms.

The main purpose of the present work is the definition of a fully automatic procedure for correlation dimension (D(2)) estimation. In the first part, the procedure for the estimation of the correlation dimension (D(2)) is proposed and tested on various types of mathematical models: chaotic (Lorenz and Henon models), periodical (sinusoidal waves) and stochastic (Gaussian and uniform noise). In all cases, accurate D(2) estimates were obtained. The procedure can detect the presence of multiple scaling regions in the correlation integral function. The connection between the presence of multiple scaling regions and multiple dynamic activities cooperating in a system is investigated through the study of composite time series. In the second part of the paper, the proposed algorithm is applied to the study of cardiac electrical activity through the analysis of electrocardiographic signals (ECG) obtained from the commercially available MIT-BIH ECG arrhythmia database. Three groups of ECG signals have been considered: the ECGs of normal subjects and ECGs of subjects with atrial fibrillation and with premature ventricular contraction. D(2) estimates are computed on single ECG intervals (static analysis) of appropriate duration, striking a balance between stationarity requisites and accurate computation requirements. In addition, D(2) temporal variability is studied by analyzing consecutive intervals of ECG tracings (dynamic analysis). The procedure reveals the presence of multiple scaling regions in many ECG signals, and the D(2) temporal variability differs in the three ECG groups considered; it is greater in the case of atrial fibrillation than in normal sinus rhythms. This study points out the importance of considering both the static and dynamic D(2) analysis for a more complete study of the system under analysis. While the static analysis visualizes the underlying heart activity, dynamic D(2) analysis insights the time evolution of the underlying system.

Algorithms↗

PubMed2004

The effect of cane use on the compensatory step following posterior perturbations.

OBJECTIVE: The compensatory step is a critical component of the balance response and is impaired in older fallers. The purpose of this research was to examine whether utilization of a cane modified the compensatory step response following external posterior perturbations. DESIGN: Single subject withdrawal design was employed. Single subject statistical analysis--the standard deviation bandwidth-method--supplemented visual analysis of the data. METHODS: Four older adults (range: 73-83 years) with balance impairment who habitually use a cane completed this study. Subjects received a series of sudden backward pulls that were large enough to elicit compensatory stepping. We examined the following variables both with and without cane use: timing of cane loading relative to step initiation and center of mass acceleration, stability margin, center of mass excursion and velocity, step length and width. RESULTS: No participant loaded the cane prior to initiation of the first compensatory step. There was no effect of cane use on the stability margin, nor was there an effect of cane use on center of mass excursion or velocity, or step length or width. CONCLUSIONS: These data suggest that cane use does not necessarily improve balance recovery following an external posterior perturbation when the individual is forced to rely on compensatory stepping. Instead these data suggest that the strongest factor in modifying step characteristics is experience with the perturbation.

Accidental Falls↗

PubMed1998

Temporal distributions of problem behavior based on scatter plot analysis.

The scatter plot is a commonly used assessment tool for identifying temporal patterns in the occurrence of behavior problems. However, the extent to which such patterns are frequently observed is unknown because little research has evaluated the general utility of the scatter plot. We conducted a large-scale analysis of within- and across-day occurrences of problem behavior by conducting continuous observations of 20 individuals living in four residential facilities. Data were recorded during 30-min intervals throughout participants' waking hours for 30 days by direct care staff and were converted into scatter plot formats. Five sets of data were excluded from further analysis due to poor interobserver agreement (below 80%). Visual analysis of the remaining 15 scatter plots indicated that none showed any reliable temporal pattern of responding. However, when the data were transformed into aggregate "control charts" based on statistical process control procedures, 12 of the 15 sets of data revealed one or more 30-min intervals during which problem behavior was more likely to occur. Results are discussed in terms of the practicality of applying statistical analyses to scatter plot data and of collecting data for the length of time needed to show statistical significance. It was concluded that detailed functional or descriptive analyses, which would reveal cause-effect or correlational relationships between behavior and specific environmental events, may be both more precise and more efficient forms of assessment.

Adolescent↗

PubMed1980

A comparison of visual and semiquantitative analysis of stress thallium-201 myocardial images in patients with suspected ischemic heart disease.

Three methods of analyzing stress thallium-201 myocardial images were performed on 79 patients with suspected coronary artery disease. The results of visual analysis of unprocessed Polaroid images, background subtracted and contrast enhanced computer generated color television images, and a semiquantitative regions-of-interest method were each compared to the coronary arteriographic findings in all patients. Analysis by the semiquantitative method achieved the highest accuracy for the classification of patients as either having or not having coronary artery disease. This method of interpreting myocardial images appears worthy of further study.

Coronary Disease↗

PubMed1992

Pattern recognition by matched filtering: an analysis of sleep spindle and K-complex density under the influence of lormetazepam and zopiclone.

The evaluation of sleep EEG patterns is mostly accomplished by visual analysis. With modern personal computers however, it is possible to perform signal detection within a reasonable length of time automatically. This paper presents a method for signal processing based on matched filtering. This allows the detection of sleep spindles and K-complexes in a sleep EEG recording with a high degree of accuracy. First the technique is described, and the results of a validation study based on the comparison of visual evaluations and computer analysis are presented. Thereafter, results of an application study are presented. Sleep spindle and K-complex density under the influence of lormetazepam and zopiclone were examined. Under both medications sleep spindle density increased while K-complex density decreased. Computation of Pearson's correlation coefficients demonstrated that the interindividual sleep spindle and K-complex variations under both treatments are highly correlated. The data suggest that lormetazepam and zopiclone, although chemically different, have a similar mode of action and display comparable effects on the sleep EEG.

Adult↗

PubMed1986

Visual acuity loss in patients with Usher's syndrome.

Using a life-table analysis, visual acuity loss with age was determined for a population of 106 patients with type 1 (N = 35) and type 2 (N = 71) Usher's syndrome. The cumulative percentage of patients maintaining visual acuity of 6/12 (20/40) or better in at least one eye by age 29 years was 69% for type 1 patients and 94% for type 2 patients. The cumulative percentage maintaining visual acuity of 6/24 (20/80) or better at this age was 89% for type 1 and 98% for type 2 patients. Within each subtype, the cumulative percentage maintaining 6/60 (20/200) or better was similar to the percentage maintaining 6/24 (20/80) or better. Knowledge of these data provides an objective basis for counseling patients with Usher's syndrome about their probability of developing loss of central visual acuity with age.

Actuarial Analysis↗

PubMed1991

Discordance of visual and quantitative analysis regarding false negative and false positive test results in thallium-201 myocardial perfusion scintigraphy.

Visual assessment and quantitative analysis of exercise thallium-201 myocardial perfusion scintigraphy was performed in 203 consecutive patients who underwent coronary arteriographic studies to identify the factors associated with false negative and false positive studies. Also the discordance between visual and quantitative analysis was evaluated. One hundred sixty-two (80%) of these 203 patients had significant coronary artery disease (CAD), i.e. a luminal stenosis greater than or equal to 50%. Fifty-two (32%) of these 162 patients with documented CAD showed negative thallium results either by visual or quantitative analysis. When interpreted visually 36/162 (22%) of patients were judged as negative, and when analyzed quantitatively 41/162 (25%) of patients were judged as negative (ns). Of the total group of 52 patients with false negative visual and/or quantitative analysis test results, 27 (17%) showed discordance between these two methods. Of the 41 patients without significant CAD, 12 (29%) showed positive thallium findings. Visual interpretation was positive in 9/41 (22%) of patients without significant CAD, and quantitative analysis in 5/41 (12%) (ns). Of the total group of 12 patients with positive visual and/or quantitative analysis test results, 10 (24%) showed discordance between these two methods. Therefore, in the total group, 37 patients (18%) showed discordance between visual and quantitative analysis. It is concluded that 1) the sensitivity and the specificity of visual interpretation and quantitative analysis of thallium-201 exercise scintigraphy for detecting CAD is similar, and 2) that there is frequent discordance of visual interpretation and quantitative analysis in thallium-201 exercise scintigraphy.

Coronary Disease↗

PubMed1992

Visualization of multimodal image information in medicine.

Radiological and clinical practice can be enhanced by improved access to multimodal image informations. Analysis, visualization, method characteristic image processing and image synthesis is needed not only for the interpretation of the images but also for performing effective consultations with clinical colleagues and computer supported therapy planning and control strategies. The distributed system RADVIS (radiological visualization) is presented which enables the fast display, three dimensional visualization and the modality oriented analysis of multimodal image informations. Based on a unique image format, modality specific evaluation procedures and two- or three dimensional processing tools of image analysis produce the input data for therapy planning programs. The easy use of this multimedia visualisation tool enables radiologists and clinicians to deal with their image data. The description of methods and procedures of the prototype, as well as typical examples of radiologic practice will demonstrate the efficiency of the presented system.

Humans↗

PubMed2004

Assessment of myocardial functional recovery in reperfused AMI: the clinical impact of visual and quantitative analysis in MCE.

The need far imaging methods to evaluate myocardial microcirculation in order to improve reperfusion therapy is increasingly recognized. Myocardial contrast echocardiography (MCE) is the most widely used technique far this purpose. Most of the reports published have focused on visual analysis of MCE. However, quantitative analysis may further improve the results of MCE in this setting, as has been demonstrated in experimental models and more recently in clinical studies. Several quantitative methods have been proposed, and these will be discussed in this report.

Coronary Angiography↗

PubMed1991

Visual and quantitative analysis of interictal SPECT with technetium-99m-HMPAO in temporal lobe epilepsy.

Interictal 99mTc-HMPAO SPECT images were compared to ictal EEG localization in 51 patients with intractable temporal lobe epilepsy to determine their usefulness for preoperative seizure focus localization. Both quantified temporal lobe asymmetry and blinded visual detection of temporal lobe hypoperfusion were employed. Visual analysis detected ipsilateral hypoperfusion in 18 (39%) of the 46 patients with a unilateral focus and contralateral hypoperfusion in 3. None of the five patients with bitemporal foci had unilateral hypoperfusion. The positive predictive value of unilateral temporal lobe hypoperfusion was 86% (18/21). Quantified anterior temporal lobe asymmetry, greater than a previously derived normal range, correctly identified the focus in 22 (48%) but gave the wrong side in 5, resulting in a predictive value of 81%. The degree of asymmetry correlated inversely with age of seizure onset, but not with other clinical parameters, histology, or verbal and nonverbal memory. The usefulness of interictal 99mTc-HMPAO SPECT for pre-operative seizure focus localization is limited by low sensitivity when performed with a conventional rotating gamma camera. This suggests that ictal or immediate postictal imaging may be necessary for this purpose.

Adult↗