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At least 397 records · Page 22Linked to original sources
PubMed2006

An automatic procedure for evaluation of single cell motility.

BACKGROUND: Cell motility is vital in many physiological and pathological processes, such as embryogenesis, inflammation, wound healing, and metastasis. However, the time-consuming step in the evaluation of individual cell motility is the analysis of hundreds of recorded images of cell cultures in general consisting of retrieving images, one at a time, and marking the positions of individual cells by a computer mouse. Therefore, the aim of the present study was to develop a novel automatic procedure for the evaluation of cell motility. MATERIALS AND METHODS: The procedure was tested on fibroblasts and glioma and adenocarcinoma cells engineered to express the green fluorescent protein by either transient transfection or adenovirus transduction, allowing automatic recognition of cell coordinates on retrieved images. RESULTS: The effects of serum growth factors, teratogenic compounds, and overexpression of transcription factors on the motile behavior of cultured cells were determined. Cell motility was estimated by both manual and automatic marking of cell position and subsequently motility parameters were computed. The results obtained by the two procedures were found to correlate significantly. CONCLUSIONS: We developed a procedure allowing automatic video recording of sparsely seeded cells transfected with a plasmid or tranduced with a recombinant virus expressing the enhanced green fluorescent protein (EGFP).

Adenocarcinoma↗
PubMed1995

The inhibition of automatic saccades in early infancy.

Adult patients with damage centered around the frontal eye fields are severely impaired in the ability to suppress unwanted automatic saccades and in the ability to make volitional eye movements. Over the first few weeks of life most saccades generated by infants appear to be automatic, and are triggered in response to exogenous factors. In the first experiment, the ability of 4-month-old infants to inhibit automatic saccades was studied by exposing them to a series of trials in which a peripheral cue stimulus predicted the location (opposite) in which a colorful, dynamic target stimulus appeared. The results indicate that 4-month-old infants are able to learn to inhibit automatic saccades to a peripheral stimulus, implying maturation of the frontal eye fields by this age. The results of Experiment 2, in which there was no contingent relationship between the cue and target, indicated that the decline in orienting to the cue observed in the first experiment was not due to differential habituation to the less-complex stimulus.

Attention↗
PubMed2006

Automatic analysis of aqueous specimens for phytoplankton structure recognition and population estimation.

An automatic microscope image acquisition, evaluation, and recognition system was developed for the analysis of Utermöhl plankton chambers in terms of taxonomic algae recognition. The system called PLASA (Plankton Structure Analysis) comprises (1) fully automatic archiving (optical fixation) of aqueous specimens as digital bright field and fluorescence images, (2) phytoplankton analysis and recognition, and (3) training facilities for new taxa. It enables characterization of aqueous specimens by their populations. The system is described in detail with emphasis on image analytical aspects. Plankton chambers are scanned by sizable grids, divers objective(s), and up to four fluorescence spectral bands. Acquisition positions are focused and digitized by a TV camera and archived on disk. The image data sets are evaluated by a large set of quantitative features. Automatic classifications for a number of organisms are developed and embedded in the program. Interactive programs for the design of training sets were additionally implemented. A long-term sampling period of 23 weeks from two ponds at two different locations each was performed to generate a reliable data set for training and testing purposes. These data were used to present this system's results for phytoplankton structure characterization. PLASA represents an automatic system, comprising all steps from specimen processing to algae identification up to species level and quantification.

Animals↗
PubMed2003

Automatic in-plane rotation for doubly-oblique cardiac imaging.

PURPOSE: To develop and test a method for automatically calculating the in-plane rotation for doubly-oblique slice geometry in order to minimize wrap artifacts for a given FOV. MATERIALS AND METHODS: The equations for in-plane rotation were formulated for doubly-oblique imaging of a cylindrical body with elliptical cross-section. Based on this formulation, automatic in-plane rotation was implemented and tested on a commercial scanner using nominal values for ellipticity of the body. RESULTS: Short axis, doubly oblique, cardiac imaging were acquired with and without in-plane rotation. The desired in-plane rotation proved to be relatively insensitive to the ellipticity of the body, permitting an automatic solution based on a nominal value. CONCLUSION: In-plane rotation is desirable for doubly oblique imaging (e.g., cardiac applications), particularly for reduced-FOV accelerated imaging such as SENSE. The proposed method, which provides an approximate solution for automatic, in-plane rotation for doubly-oblique imaging, was demonstrated.

Artifacts↗
PubMed2001

Automatic function switching and its usefulness in peptide and protein analysis using direct infusion microspray quadrupole time-of-flight mass spectrometry.

Automatic function switching has been investigated for high-throughput protein identification and sequencing of peptides using direct infusion of tryptic digests on a quadrupole time-of-flight instrument. The increase in speed and the high quality of data make it a favourable technique for tandem mass spectrometry when compared to manual selection of each precursor ion; these advantages are not restricted to combined LC/MS/MS analyses for which the automatic function-switching mode was originally developed. This mode was compared to analyses performed using a slow scan of the quadrupole analyzer with repeated recording of product ion spectra. For the specific purpose of generating product ion data for sequence determination (as opposed to surveying all precursors of a selected product ion), the automatic function-switching mode was, as expected, markedly superior with respect to speed of analysis and quality of data. Furthermore, the automatic function-switching mode provides greater versatility with respect to selection of optimal collision energies.

Alcohol Dehydrogenase↗
PubMed2002

Software algorithm for automatic interpretation of mass spectra of glycerolipids.

A new software algorithm for automatic interpretation of mass spectra of glycerolipids has been developed. The algorithm utilizes a user-specified list of parameters needed to process the spectra. The compounds in mass spectra are identified according to range of measured m/z values, after which the spectra are automatically corrected by the content of naturally occurring isotopes and ion intensities of identified compounds by response correction factors. Automatic processing of the spectra was shown to be accurate and reliable by testing with numerous spectra of glycerophospholipids obtained by liquid chromatography/electrospray ionization mass spectrometry and by comparing the results with manual interpretation of the spectra. If quantitative analysis using internal standards is performed, all the identified compounds in the sample are quantified automatically. A dilution factor may be defined for each sample and is applied to correct the alterations in sample concentration during sample preparation. Processing of several replicate spectra simultaneously produces mean results with standard deviations. The software may also be used to subtract the results of two analyses and to calculate the mean result of replicate subtractions. The algorithm was shown to save time and labor in repetitive processing of mass spectra of similar type. It may be applied to processing of spectra obtained by various mass spectrometric methods.

Algorithms↗
PubMed2001

Automatic assignment of NOESY cross peaks and determination of the protein structure of a new world scorpion neurotoxin using NOAH/DIAMOD.

The 3D NMR structures of the scorpion neurotoxin, CsE-v5, were determined from the same NOESY spectra with NOAH/DIAMOD, an automated assignment and 3D structure calculation software package, and with a conventional manual assignment combined with a distance geometry/simulated annealing (X-PLOR) refinement method. The NOESY assignments and the 3D structures obtained from the two independent methods were compared in detail. The NOAH/DIAMOD program suite uses feedback filtering and self-correcting distance geometry methods to automatically assign NOESY spectra and to calculate the 3D structure of a protein. NOESY cross peaks were automatically picked using a standard software package and combined with 74 manually assigned NOESY peaks to start the NOAH/DIAMOD calculations. After 63 NOAH/DIAMOD cycles, using REDAC procedures in the last 8 cycles, and final FANTOM constrained energy minimization, a bundle of 20 structures with the smallest target functions has a RMSD of 0.81 A for backbone atoms and 1.11 A for all heavy atoms to the mean structure. Despite some missing chemical shifts of side chain protons, 776 (including 74 manually assigned) of 1130 NOE peaks were unambiguously assigned, 150 peaks have more than one possible assignment compatible with the bundle structures, and only 30 peaks could not be assigned within the given chemical shift tolerance ranges in either the D1 or the D2 dimension. The remaining 174, mainly weak NOE peaks were not compatible with the final 20 best bundle structures at the last NOAH/DIAMOD cycle. The automatically determined structures agree well with the structures determined independently using the conventional method and the same NMR spectra, with the mean RMSD in well-defined regions of 0.84 A for bb and 1.48 A for all heavy atoms from residues 2-5, 18-26, 32-36, and 39-45. This study demonstrates the potential of the NOAH/DIAMOD program suite to automatically assign NMR data for proteins and determine their structure.

Amino Acids↗
PubMed1998

Different aspects of the effects of thapsigargin on automatism, contractility and responsiveness to phenylephrine in cardiac preparations from rats and guinea pigs.

Sarcoplasmic reticulum (SR) Ca(2+)-ATPase play a very important role in excitation-contraction coupling in the heart. The effects of thapsigargin (TG), a selective inhibitor of SR Ca(2+)-ATPase in the heart muscle, on automatism and contractility of the rat and guinea pig heart were examined. Experiments were performed on isolated right auricula and right ventricle papillary muscle. The following parameters were registered: force of contraction (Fc); rate of rise of force (+dF/dt); rate of fall of force (-dF/dt); time to peak contraction (ttp); duration of relaxation phase of contraction at the level of 10% of total amplitude (tt10); and automatism (b.p.m.). Additionally, the influence of thapsigargin on the effects of phenylephrine on the above mentioned parameters were studied. It was found that TG (1 microM) decreased only the automatism in rat heart, but increased automatism and ttp duration and decreased Fc in guinea pig heart. The positive force-frequency relation in the guinea pig heart was attenuated. The effects of phenylephrine in the rat heart were not significantly different before and after pretreatment with TG. Alternatively, pretreatment with TG exerted a profound influence on the effects of phenylephrine in the guinea pig heart. The results indicate that TG has different effects on the guinea pig and rat hearts. The reason for this could be due to species differences, i.e. the weaker crossing of TG through the membrane of rat myocytes or a different mechanism of Ca2+ homeostasis in rat and guinea pig hearts.

Adrenergic alpha-Agonists↗
PubMed2005

Toward automatic computer aided dental X-ray analysis using level set method.

A Computer Aided Dental X-rays Analysis (CADXA) framework is proposed to semi-automatically detect areas of bone loss and root decay in digital dental X-rays. In this framework, first, a new proposed competitive coupled level set method is proposed to segment the image into three pathologically meaningful regions using two coupled level set functions. Tailored for the dental clinical environment, the segmentation stage uses a trained support vector machine (SVM) classifier to provide initial contours. Then, based on the segmentation results, an analysis scheme is applied. First, the scheme builds an uncertainty map from which those areas with bone loss will be automatically detected. Secondly, the scheme employs a method based on the SVM and the average intensity profile to isolate the teeth and detect root decay. Experimental results show that our proposed framework is able to automatically detect the areas of bone loss and, when given the orientation of the teeth, it is able to automatically detect the root decay with a seriousness level marked for diagnosis.

Algorithms↗
PubMed1992

Automatic detection of the left ventricular myocardium long axis and center in thallium-201 single photon emission computed tomography.

A new method for centering and reorienting automatically the left ventricle in thallium-201 myocardial single photon emission computed tomography (SPET) is proposed. The processing involves the following steps: (a) the transverse sections of the left ventricle are segmented, (b) the three-dimensional skeleton of the left ventricle is extracted using tools of mathematical morphology, (c) the skeleton is fitted to a quadratic surface by the least-squares method, (d) the left ventricle is reoriented and centered using the long axis and the coordinates of the centre of the quadratic surface. A series of 30 consecutive exercise and redistribution 201Tl SPET studies were centered and reoriented by two operators twice with this method, and twice manually. There was no significant difference in the mean realignment performed by the automatic and the manual methods while centering differed moderately in some instances. In all cases and for all parameters, the reproducibility of the automatic method was 1.00, while it ranged between 0.74 and 0.98 with the manual centering and reorientation. This automatic approach provides a fast and highly reproducible method for the reconstruction of short- and long-axis sections of the left ventricle in 201Tl SPET.

Adult↗
PubMed1976

Automatic perimetry in glaucoma visual field screening. A clinical study.

Automatic computerized perimetry was compared to careful manual selective perimetry (a variant of that proposed by Armaly) in 181 eyes of 100 patients from a glaucoma open-care unit. The results of the two methods were very similar. Thus all defects found were identified by the automatic perimeter, and one pathologic field was missed by the manual selective perimetry. The automatic examination gave 16% false positive results and the manual 11% when optimally performed. The false positives could be greatly reduced (to 4.4% and 3.3% respectively) by rescreening. In a comparison with "routine" perimetry, the automatic screening is shown to be superior.

Adult↗
PubMed1980

Automatic (Octopus) and manual (Goldmann) perimetry in glaucoma.

Of 115 patients with chronic open angle glaucoma or suspected glaucoma 115 eyes were subjected to a visual field examination with the manual Goldmann perimeter and the automatic Octopus perimeter. In 84.4 +/- 8.9% the automaton detected more visual field loss, including 27.8 +/- 10.9% of the eyes where no visual field loss was found by the manual perimetry. Since some eyes with normal fields on manual perimetry and abnormal fields detected by automatic perimetry remained abnormal on retesting, it is assumed that scotomas found by automatic perimetry and not shown by manual perimetry constitute false-negative manual fields rather than false-positive automatic fields.

Adult↗
PubMed1988

Automatic and effortful processing in attention deficit/hyperactivity disorder.

Twenty-five boys with Attention Deficit/Hyperactivity Disorder and 23 age-matched controls were compared on verbal memory tasks differentiating automatic versus effortful information processing. Automatic processing tasks included the recognition of new or old words in a list and the recognition of frequency of occurrence of words in a list. Effortful tasks included free recall of lists of both related and unrelated words. Hyperactive boys did not differ from controls in automatic processing capabilities but demonstrated significantly poorer effortful processing. Intercorrelations of the variables revealed high correlations between scores on effortful measures and also raise questions about the purity of automaticity in some tasks employed. Stepwise discriminant analysis demonstrated that free recall of related words (an effortful task) best discriminated between groups. Effort-related processing in hyperactive and normal children is discussed in relation to variables of motivation, affect, arousal, and other higher-order cognitive processes.

Arousal↗
PubMed1997

Quantitative ultrasound imaging at the calcaneus using an automatic region of interest.

A new approach to measuring bone properties at the calcaneus using ultrasound parametric imaging has recently emerged. However, an additional source of observer-related error is the substantial regional variations in the pattern of ultrasound parameters. The contribution of intra-observer and inter-observer variability to the coefficient of variation can be eliminated using an algorithm which selects the region of interest (ROI) completely automatically. The objective of the present study was the clinical assessment of an automatic ROI for both broadband ultrasonic attenuation (BUA) and speed of sound (SOS) measurement using ultrasound parametric imaging. The automatic ROI was defined as the circular region of lowest attenuation in the posterior tuberosity of the calcaneus. We have tested this algorithm using clinical images of the calcaneus from 265 women. Mean coefficients of variation were 1.6% (95% confidence interval 1.4%-1.9%) and 0.26% (95% confidence interval 0.23%-0.32%) for BUA and SOS respectively (standardized CV was 2.1% for BUA and 2.6% for SOS). Z-scores in an osteoporotic group were -0.61 and -0.52 for BUA and SOS respectively. In healthy women, the age-related decline was -0.50 dB/ MHz per year (0.7%/year) for BUA and -1.2 m/s per year (0.08%/year) for SOS. In the subgroup of healthy postmenopausal women, using stepwise multiple regression, we found that BUA was predicted best by years since menopause (YSM) and weight, with overall model r2 = 0.28; SOS was predicted best by YSM only (r2 = 0.21). Neither the range of biological variation of ultrasound parameters nor the clinical value were affected by the choice of the region of lowest attenuation for measurement. The automatic procedure was totally independent of operator interaction, therefore excluding loss of precision due to intra- or inter-observer variability. The results showed the high precision and robustness of the procedure. These factors make this approach viable for routine clinical use.

Aged↗
PubMed1996

The automatic selection of ventilation parameters during the initial phase of mechanical ventilation.

OBJECTIVE: To test a method that allows automatic set-up of the ventilator controls at the onset of ventilation. DESIGN: Prospective randomized crossover study. SETTING: ICUs in one adult and one children's hospital in Switzerland. PATIENTS: Thirty intubated stable, critically ill patients (20 adults and 10 children). INTERVENTIONS: The patients were ventilated during two 20-min periods using a modified Hamilton AMADEUS ventilator. During the control period the ventilator settings were chosen immediately prior to the study. During the other period individual settings were automatically determined by the ventilatior (AutoInit). MEASUREMENTS AND RESULTS: Pressure, flow, and instantaneous CO2 concentration were measured at the airway opening. From these measurements, series dead space (V(DS)), expiratory time constant (RC), tidal volume (VT, total respiratory frequency (f(tot), minute ventilation (MV), and maximal and mean airway pressure (Paw, max and Paw, mean) were calculated. Arterial blood gases were analyzed at the end of each period. Paw, max was significantly less with the AutoInit ventilator settings while f(tot) was significantly greater (P < 0.05). The other values were not statistically significant. CONCLUSIONS: The AutoInit ventilator settings, which were automatically derived, were acceptable for all patients for a period of 20 min and were not found to be inferior to the control ventilator settings. This makes the AutoInit method potentially useful as an automatic start-up procedure for mechanical ventilation.

Adult↗
PubMed1990

Comparison between classic-differential and automatic shunt functioning on the basis of infusion tests.

Infusion tests were performed in order to examine cerebrospinal compensatory ability in two groups of patients with impaired compensation, subjected to shunt implantation. The functioning of the classic differential shunts was compared to the automatically (Orbis-Sigma) functioning shunts. The reference group, with intact compensatory parameters is also presented. The influence of different types of shunts on the intracranial compensation ability was compared. Automatic shunts produce less decrease in the resorption resistance of CSF in the post-shunted examination than the classic differential shunts. Classic differential shunts disturb the mono-exponential character of the pressure-volume relationship in a higher degree than automatic shunts. Shunt functioning models were proposed as well as the method of detection of eventual recovery to the normal resorption reserve. This method can be applied only to patients with automatic shunts.

Adult↗
PubMed1990

Histamine and abnormal automaticity in barium- and strophanthidin-treated sheep Purkinje fibers.

We used intracellular microelectrodes to study the effects of histamine on both normal and abnormal automaticity in sheep Purkinje fibers. Histamine, dimaprit and 4-methylhistamine caused a similar reduction of the action potential duration in driven Purkinje fibers. Histamine (10-6 M) induced spontaneous activity in p previously quiescent preparations more often than did equimolar concentrations of dimaprit and 4-methylhistamine. The effects of histamine on automaticity were enhanced in the presence of barium In fact histamine, at concentrations which were unable to induce automaticity in normal preparations, induced it in the presence of barium. In Purkinje fibers manifesting barium-induced automatic activity, histamine (10-7--10-6M) significantly increased the average number of spontaneous action potentials and shortened the time of their appearance. In the same range of concentrations, histamine dose-dependently increased the iological manifestation of calcium overload. Histamine (10-6--10-4M) increased the OAP amplitude of strophanthidin -treated Purkinje fibers, eventually inducing triggered extrabeats. All these previously described effects were selectively blocked by cimetidine (10-5 M). It is concluded that histamine may induce cardiac arrhythmias under conditions of calcium overload and that this effect may be due to induction or enhancement of oscillatory afterpotentials.

Animals↗
PubMed1992

Diagnostic value of automatically interpreted oculopneumoplethysmography.

The diagnostic value of the Gee-oculopneumoplethysmography test for the detection of hemodynamically significant carotid artery obstructions has frequently been questioned due to the rather low agreement with arteriography. The kappa-corrected diagnostic accuracy of this test has been reported to be in the range between 0.54 and 0.68. These values indicate a "fair to good" agreement with arteriography. One of the causes for this rather low agreement is the variability in the interpretation of oculopneumoplethysmography recordings. Automatic analysis of oculopneumoplethysmography recordings might minimize the risks of misinterpretation and might improve the clinical significance of the Gee-oculopneumoplethysmography test. By assessing the signals of a conventional Gee-oculopneumoplethysmography apparatus in a personal computer, this automatic analysis has been realized. In a clinical study (population of 85 patients) the diagnostic value of automatic analysis of oculopneumoplethysmography recordings has been evaluated. The automatically interpreted Gee-oculopneumoplethysmography test had a kappa-corrected diagnostic accuracy of 0.71 on a "per side" base and of 0.76 on a "per patient" base.

Adult↗