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At least 721 records · Page 40Linked to original sources
PubMed1976

Electroencephalographic changes during experimental hangover.

The EEG was recorded in 27 subjects during hangover. Male healthy volunteers drank 1.75 g/kg body weight of ethanol in 3 h and the EEG was recorded 14-16 h later when the degree of hangover was highest. For control purposes a second EEG was recorded after a similar session when subjects drank water instead of ethanol. A third record was taken in normal laboratory conditions. T5-A1 and O1-A1 derivations were subjected to computer analysis from which spectral and frequency parameters were calculated. Visual analysis of the EEG during hangover showed a decrease and slowing of alpha activity and an increase in theta activity. Spectral analysis of the EEG gave a statistically significant increase in 7-8 c/sec activity during hangover. The EEG change could not be explained in terms of blood alcohol level, hypoglycaemia or acidosis. Also fatigue could be excluded as a cause of EEG change by means of "water controls". The conclusion is that the slowing of the EEG during hangover is caused by the depressant action of ethanol, or its metabolites, on cortical function.

Adolescent↗
PubMed1989

A simple electronic and computer system for automatic spindle detection.

The authors present a new system for the automatic detection of sleep spindles. The electronic and computer analysis are described and a comparison between automatic and visual analysis, performed by two independent readers, was carried out with the aim of evaluating the reliability of the system. Results are discussed and compared with those of different systems already described.

Electroencephalography↗
PubMed2002

Optically imageable metastatic model of human breast cancer.

We report an optically imageable orthotopic metastatic nude mouse model of the human breast cancer MDA-MB-435 expressing green fluorescent protein (GFP). We demonstrate fluorescent imaging of primary and metastatic growth in live tissue and in intact animals. Fragments of tumor tissue expressing GFP were sutured into the pocket in the right second mammary gland. Tumor tissue was strongly fluorescent, enabling whole-body imaging of tumor growth by week 5. Neovascularization of the primary tumor was also visualized by whole-body imaging by contrast of the vessels to the fluorescent tumor. At autopsy, the MDA-MB-435-GFP was found to have metastasized to various organs, including the lung in 55% of the animals, the lymph nodes in 15% of the animals including axillary nodes, and the liver in 10% of the animals. These metastases could be visualized in fresh tissue by fluorescent imaging. Detailed fluorescence analysis visualized extensive metastasis in the thoracic cavity and the lymphatic system. Large metastatic nodules in the lung involved most of the pulmonary parenchyma in all lobes. Lymph node metastasis was found mainly in the axillary area. In the liver, fluorescent macroscopic metastatic nodules were found under the capsule. The metastatic pattern in the model thus reflected clinical metastatic breast cancer and provides a powerful model for drug discovery for this disease.

Adult↗
PubMed2006

[Study on intelligent system of hyper-spectral data gathering based on wireless data communication technology in farm machinery].

In order to meet the needs of highly dense and overall farmland information gathering, wireless data communicating, and real-time processing in the precision agriculture, this system integrated GPS, GIS and RS based on the technology of computer and wireless data transmission. On the one hand, the system makes DGPS and Hyper-spectrograph integrated through the AT891v52 MCU, providing the accurate space position and realizing the integration of spectrum data acquisition and orientation. On the other hand, the system realizes the communication between the data gathering control system and the microcomputer by using the nRF905 system. Meanwhile the system has realized the visualized analysis and management of the spectrum data by integrating Visual Basic and Map-Objects into GIS, displaying real-time trace of moving point and some related attributes of the moving point in map layers, and calculating crop derivative spectra and crop vegetation index NDVI etc. Thus, sufficient information was provided for expert system and decision support system of precision agriculture.

English Abstract↗
PubMed1994

First-pass ventricular ejection fraction using a single-crystal nuclear camera.

UNLABELLED: The purpose of the study was to evaluate the reliability of ejection fractions obtained from first-pass radionuclide ventriculography with a large field-of-view tomographic single-crystal gamma camera. METHODS: A SPECT camera had its electronics redesigned to improve counting efficiency and was equipped with an experimental ultra-high sensitivity collimator. Left ventricular ejection fraction (LVEF) was measured in 28 patients by 30 degrees RAO first-pass imaging and by "best septal view" LAO planar equilibrium radionuclide ventriculography on a conventional small field of view Anger camera. For 28 other patients, first-pass ejection fractions were compared to multicrystal gamma camera values. Visual analysis was performed to judge clinical acceptability of first-pass images for identification of wall-motion abnormalities. RESULTS: Linear regression analysis of first-pass against equilibrium ejection fraction demonstrated good correlation (r = 0.92; slope = 0.90; intercept = 3.8; s.e.e. = 6.4%). First-pass ejection fraction values also correlated linearly with multicrystal camera values for the left ventricle (r = 0.94; slope = 1.05; intercept = 1.3; s.e.e. = 5.3%). For a subgroup of 19 patients, single-crystal camera right ventricle ejection fraction demonstrated good correlation with multicrystal camera values (r = 0.82; slope = 1.15; intercept = 1.3; s.e.e. = 6.1%). Interobserver variability correlated as r = 0.99 for LVEF ejection fraction and r = 0.92 for RVEF. Chi-square analysis of single-crystal first-pass image visual scores versus those from the gated equilibrium acquisitions showed close agreement (p < 10(-8)). CONCLUSIONS: The evaluated camera/collimator system measured left and right ventricular ejection fraction accurately. Lung frame correction and dual regions were superior to paraventricular background correction and a fixed end-diastolic region.

Feasibility Studies↗
PubMed2001

A study to determine the accuracy of a computerized algorithm for interpretation of EEGs.

The main use of computerized EEG has been in sleep studies. A comprehensive system of interpreting routine EEGs by computers has not yet been developed and is technically difficult. We have tried to incorporate computers in the analysis and interpretation of EEGs by using information obtained from visual analysis of EEG in the present work. The purpose of this study was to determine the accuracy of such an algorithm. An electroencephalographer visually analyzed routine EEGs and the data was entered into an EEG Worksheet. The electroencephalographer then interpreted the data and a report was dictated and transcribed. Data from the EEG Worksheet was entered into a computer for interpretation, clinical correlation, and report preparation. Results indicate that the algorithm used with the EEG Worksheet can correctly interpret and clinically correlate visually-analyzed EEG data entered into a computer and reduce time for EEG report generation.

Adolescent↗
PubMedDate not supplied

Sustained reduction of exercise perfusion defect extent and severity with isosorbide mononitrate (Imdur) as demonstrated by means of technetium 99m sestamibi.

BACKGROUND: The impact of long-acting nitrates on the extent and severity of stress-induced myocardial ischemia is not well described, especially after long-term treatment. METHODS: Forty patients with chronic stable angina and reversible ischemia on an exercise stress myocardial perfusion single photon emission computed tomography (ex-SPECT) were prospectively studied in a 6-week period. At baseline, rest thallium-201/exercise stress technetium 99m sestamibi SPECT was performed, followed by treatment with extended-release isosorbide 5-mononitrate (5-ISMN, Imdur). Follow-up ex-SPECT was performed 5 days and 6 weeks after the initiation of therapy with extended-release 5-ISMN. The exercise treadmill testing (ETT) protocol and exercise duration of the follow-up studies were the same as that of the baseline ETT. Defect extent and severity were analyzed both by means of an automated quantitative method, with CEqual software, and visually, with a 20-segment scoring system (which was also used to derive a summed stress score [SSS]). RESULTS: In the 6-week study period, significant reductions occurred in both the extent and the severity of exercise-induced ischemia by means of quantitative SPECT (13.8% [P<.0003] and 12.7% [P<.0003], respectively). There was no significant change in these variables between stages 2 (day 5) and 3 (6 weeks), indicating no development of tolerance to the nitrate effect. Similar reductions were noted by means of the visual analysis (SSS reduction of 13.0% [P<.002]) in the entire study period. CONCLUSIONS: Patients with chronic-stable-angina treated with a long-acting nitrate demonstrate improvement in myocardial perfusion defect extent and severity in an extended period by means of both visual and quantitative analysis of sequential exercise testing to the same rate-pressure product end point.

Aged↗
PubMed2005

Characterization of breast lesion using double phase Tc-99m Tetrofosmin scintimammography: comparison of visual and quantitative analyses.

UNLABELLED: To compare the diagnostic performances of visual and quantitative indices of double phase Tc-99m Tetrofosmin scintimammography (TF-SMM) for the detection of breast cancer. METHODS: Double phase TF-SMM (early, 10 min; delayed, 3h) were performed after injection of 925 MBq of Tc-99m Tetrofosmin in 75 highly suspected breast cancer patients (malignant: 49, benign: 26). For visual analysis, five scoring method was used. For quantitative analysis, early, delayed lesions to non-lesion ratios (L/Ns) and washout rate (%, WR) were calculated. Receiver operating characteristic curve (ROC) analyses were performed to determine the optimal visual grade, to calculate cut-off values of quantitative indices, and to compare visual and quantitative diagnostic performances. RESULTS: When over grade 3 of visual grade was used as cut-off value in the defection of primary breast cancer, the sensitivity and specificity were 75.5 and 80.8%, respectively. The positive and negative predictive values were 88.1 and 63.6%, respectively. The area under curve was 0.824 (95% CI, 0.719-0.902) and standard error (S.E.) was 0.047. The optimal L/N ratios were 3.13 for early and 2.56 for delayed image. When early L/N 3.13 was used as cut-off point, the sensitivity and specificity of TF-SMM were 61.2 and 96.2%, respectively. The positive and negative predictive values were 96.8 and 56.8%, respectively. The AUC was 0.809 (95% CI, 0.702-0.890) and S.E. was 0.049. When delayed L/N 2.56 was used as cut-off value, the sensitivity and specificity were 46.9 and 96.2%, respectively. The positive and negative predictive values were 95.8 and 49%, respectively. The AUC was 0.741 (95% CI, 0.627-0.835) and S.E. was 0.057. No statistical differences between visual assessment and quantitative analysis of early image (difference between area, 0.015; S.E., 0.044; 95% CI, -0.072 to 0.102; p = 0.736) and delayed image (difference between area, 0.083; S.E., 0.054; 95% CI, -0.023 to 0.060; p = 0.189) was noted. However, early L/N was superior to delayed L/N ratio for the detection of breast cancer (difference between area, 0.068; S.E., 0.033; 95% CI, 0.004-0.132; p = 0.038). CONCLUSION: In conclusion, TF-SMM showed a favorable diagnostic accuracy in differentiating benign from malignant breast lesions. The optimal visual interpretation grades for the detection of primary breast cancer of double phase TF-SMM were grade 4 and 5. The optimal quantitative indices for the detection of breast cancer were 3.12 for early L/N and 2.56 for delayed L/N. Visual and quantitative analyses showed similar results. However, early L/N was superior to delayed one for the detection of breast cancer. Therefore, the delayed image should not be routinely performed for the purpose of primary breast cancer detection. These findings deserve further investigation on a larger number of patients to be performed to allow a better validation of the differentiation malignant from benign breast lesions using double phase TF-SMM.

Breast Neoplasms↗
PubMed1984

Estimation of the frequency of malformed sperm by slit scan flow cytometry.

We have investigated the utility of Slit Scan Flow Cytometry (SSFCM) for measuring the frequencies of malformed sperm heads in control and mutagen treated B6C3F1/CRL mice. In SSFCM, fluorescence profiles of sperm heads stained with the DNA-specific fluorescent dye acriflavine were recorded for sperm flowing lengthwise through a 2.5-microns-thick laser beam. Malformed sperm were detected as having fluorescence profiles that differed substantially from an average fluorescence profile for sperm from untreated mice. Specifically, a sum of squared difference (SSD) value was calculated for the fluorescence profile of each sperm according to the equation (Formula: see text) where c(i) and t(i) are the ith values for the fluorescence profiles from control and test sperm, respectively. Profiles whose SSD exceeded a threshold value of 20 were considered to be from malformed sperm. We measured fluorescence profiles for 500 sperm per mouse from five control mice, five mice injected intraperitoneally daily for 5 days with a total of 375 mg/kg of body weight methyl methane sulfonate (MMS), and for 30 mice injected intraperitoneally daily for 5 days with total doses of procarbazine ranging from 125 mg/kg to 1,250 mg/kg. Sperm were collected from the caudae epididymides 35 days after the last injection. Frequencies of malformed sperm in these samples were also estimated by visual analysis. All samples were analyzed in double blind fashion. The visual and SSFCM malformed sperm frequencies for the samples from control, MMS-treated, and procarbazine-treated mice were correlated (r = 0.83). A dose effect was seen with both the visual and SSFCM estimates for the sperm from the procarbazine-treated mice.

Animals↗
PubMed2004

Investigating human color preferences in the perception of complex three-dimensional structures.

This article describes preliminary results of a investigation that addresses the problem of human color perception in the visual analysis of complex three-dimensional shapes. We built 3D visualization models of synthetic neural cells, and designed two experiments to identify user preferences for color when observing and executing tasks on these 3D models. Though preliminary, the results obtained from these experiments are consistent and indicate that some trends exist that deserve further investigation.

Color Perception↗
PubMed2006

Weakened center-surround interactions in visual motion processing in schizophrenia.

Schizophrenia is often accompanied by a range of visual perception deficits, with many involving impairments in motion perception. The presence of perceptual abnormalities may impair neural processes that depend on normal visual analysis, which in turn may affect overall functioning in dynamic visual environments. Here, we examine the integrity of suppressive center-surround mechanisms in motion perception of schizophrenic patients. Center-surround suppression has been implicated in a range of visual functions, including figure-ground segregation and pursuit eye movements, visual functions that are impaired in schizophrenia. In control subjects, evidence of center-surround suppression is found in a reduced ability to perceive motion of a high-contrast stimulus as its size increases. This counterintuitive finding is likely a perceptual correlate of center-surround mechanisms in cortical area MT. We now show that schizophrenic patients exhibit abnormally weak center-surround suppression in motion, an abnormality that is most pronounced in patients with severe negative symptoms. Interestingly, patients with the weakest surround suppression outperformed control subjects in motion discriminations of large high-contrast stimuli. This enhanced motion perception of large high-contrast stimuli is consistent with an MT abnormality in schizophrenia and has a potential to disrupt smooth pursuit eye movements and other visual functions that depend on unimpaired center-surround interactions in motion.

Adult↗
PubMed1993

An application of phase spectral analysis to amplitude-modulation following response.

A phase spectral analysis developed by Fridman (1982) was applied to the detection of amplitude-modulated frequency following response (AMFR) and its clinical usefulness was evaluated. A 1000 Hz sinusoidally amplitude-modulated tone with a modulation frequency of 40 Hz and a modulation depth of 90% was delivered to the right ear of 10 normal-hearing subjects. According to Fridman's technique, an ensemble of sweeps was divided into 10 groups and group averages were obtained. Then phase variances were calculated using fast Fourier transform for the group averages. In order to determine the optimal conditions of analysis for constructing an automatic detection program using phase spectral analysis, frequency spacing, number of sampling points and number of sweeps averaged per group were investigated. The sensitivity of phase spectral analysis for automatic detection of AMFR was also evaluated. The results suggested that the optimal number of sampling points and frequency spacing are 512 points and 4.9 Hz (observation window 204.8 ms), respectively. Concerning the average number of sweeps, the synchrony measure of the frequency component corresponding to the modulation frequency increased as the number of sweeps increased. Furthermore, it was demonstrated that threshold determination by phase spectral analysis is more sensitive than detection of the threshold by visual analysis of waveform configuration.

Adult↗
PubMed1990

[Wilson's disease. Presentation of a case with special reference to the study of evoked visual potentials].

In the present work the Authors report one case of Wilson's disease showing peculiar characteristics diagnosed in pediatric-age patients. In this case, a deep electrophysiological visual analysis was carried out six years after diagnosis. The evoked visual potential alterations might be connected to a retina dysfunction. Further studies should be carried out in order to support such hypothesis.

Child↗
PubMed2002

Fully automated analysis of colonic manometry recordings.

The purpose of this study was to develop a computer program for fully automated analysis of all presently known motor patterns in human colonic motility recordings. Colonic pressure recordings obtained from 24 healthy volunteers were used. Algorithms were developed for the detection and numerical analysis of five types of pressure waves: antegrade, retrograde, simultaneous, high-amplitude and isolated pressure waves. Furthermore, periodical motor activity was quantified. Validation was performed by comparison with visual analysis by two experienced observers. Patterns recorded during day- and night-time were compared using multiple-factor analysis of variance with Bonferroni correction. Automated analysis correlated well with visual peak detection (r = 0.98, P <0.01) and detection of antegrade pressure waves (r = 0.98, P <0.01). Most motor patterns showed a diurnal variation. During the night, prevalences of antegrade (938 vs 455; P <0.05), retrograde (112 vs 81; P <0.05), high-amplitude (12.9 vs 1.3; P <0.05), isolated pressure waves (1114 vs 765; P <0.05), and periodic motor activity were decreased (7.33 vs 4.47%; P <0.05). However, when expressed as percentage of absolute numbers of pressure waves, prevalences remained constant. In conclusion, fully automated analysis of all hitherto described colonic motility patterns is feasible. During the night, overall wave prevalences markedly decreased, but the distribution over the various motor patterns was preserved.

Adult↗
PubMed2001

Role of motion integration in contour perception.

Contours are believed to play a key role in the visual analysis of scenes by the primate brain. In dynamic scenes, the presence of contours is often signaled by discontinuities in motion fields. However, it is unclear whether the motion fields over which the visual system extracts discontinuities, correspond to the local optic-flow or the pattern motion fields obtained by integrating local estimates. A resolution of this issue would provide important clues about the organization of visual motion and form analysis processes. In this paper, we present experimental evidence which suggests that the perception of motion defined contours is strongly dependent on motion integration - an operation that is believed to take place relatively late in the visual stream.

Form Perception↗
PubMed2000

Tissue characterization of atherosclerotic plaques by intravascular ultrasound radiofrequency signal analysis: an in vitro study of human coronary arteries.

BACKGROUND: Conventional gray-scale images of intravascular ultrasound (IVUS) cannot accurately differentiate histologic subtypes of sonolucent coronary plaques with or without a lipid core. METHODS: We analyzed radiofrequency signals obtained in vitro from 24 regions of interest (ROI) of noncalcified (sonolucent) plaques in 10 atherosclerotic coronary artery specimens pressure-fixed by formalin. Radiofrequency signals were sampled with a 30-MHz IVUS catheter and digitized at 500 MHz in 8-bit resolution. The ROIs were histologically categorized into 12 plaques with a lipid core and 12 plaques without it. Integrated backscatter and statistical parameters of the radiofrequency envelope (mean/SD ratio [MSR], skewness, and kurtosis) within the ROI were calculated offline, and their ability to detect a lipid core was compared with visual analysis of the IVUS video images. In the group with lipid cores, percent area of a lipid core in each ROI was measured in a digitized histologic image by a computerized planimeter. RESULTS: Sensitivity and specificity of MSR, skewness, and kurtosis for lipid core detection were substantially greater than visual video image analysis (83.3% and 91.7%, 100% and 91.7%, 100% and 91.7% vs 53.3% and 71.7%). Furthermore, the parameters of integrated backscatter, MSR, skewness, and kurtosis were significantly correlated to percent of core area (r = -0.64, -0.73, 0.78, and 0.63, respectively; P<.05). CONCLUSIONS: Compared with IVUS video images, the parameters of radiofrequency signal analysis may be used to aid in more accurate detection and quantitative evaluation of a lipid core, which is one of the major factors of a vulnerable coronary plaque.

Coronary Artery Disease↗
PubMed1992

Everett Kinsey Lecture. Hyperacuity, a technique for assessment of results of refractive surgery.

In recent years there have been rapid advancements in corneal refractive surgery. The results of keratorefractive procedures are generally not predictable and wound healing effects interfere with the stability. The problems with predictability and stability make the usual visual performance indices such as visual acuity and contrast sensitivity testing insufficiently refined for functional assessment of visual performance after keratorefractive surgery. We argue that there is a need for precise visual functional analysis that parallels and complements the advanced technologies employed in ophthalmic surgery. Results from hyperacuity test paradigms are put forth as one set of precise, reliable bench marks for characterizing the results of refractive surgery. Hyperacuity testing is well suited for analysis of visual performance after keratorefractive surgery because the procedure is resistant to optical image degradation and requires a higher-order analysis by the visual system. The uses of hyperacuity techniques are discussed.

Humans↗