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At least 613 records · Page 34Linked to original sources
PubMed1983

Effects of psychotropics on the periodic fluctuation in EEG synchronized with respiratory rhythms during cough reflex.

It is known that the psychotropics reduce the cough reflex. To clarify the relation between the higher centers and cough reflex, we investigated the psychotropics property of the respiratory periodic fluctuation in EEG during cough reflex and after administration of psychotropics. Male mongrel dogs immobilized were maintained with artificial respiration. The efferent activities of phrenic nerve and scalp EEG were recorded, and on the basis of the resulting observations, crosscorrelation coefficients were computed using a digital computer. The cough reflex was accompanied by an increase in crosscorrelation coefficient (C. C.) between EEG and phrenic nerve activities. the C. C. between EEG and phrenic nerve activities decreased after iv administration of chlorpromazine ( mg/kg), while administration of imipramine (1-3 mg/kg) and diazepam (1-3 mg/kg) increased the C. C., respectively. The increase in the C. C. observed during cough reflex was inhibited by iv administration of these three drugs. The fact that the C. C. increased during cough reflex suggested that the ascending output from respiratory center to the higher center reinforced during this period. Furthermore, it is suggested that the psychotropics inhibited the neuronal mechanisms of the brain stem that plays an important role in cough reflex by acting upon the feedback loop located between the respiratory center and the higher centers.

Animals↗
PubMed1995

The design and use of a computer-based digital image acquisition, management, and communications system for conferencing in pathology.

The Roche ImageManager is a PC computer-based system, running under Windows 3.1. This system allows the storage, viewing, printing, and transmission of, and conferencing on large sets of high resolution, color images from various sources. Images may be acquired at resolutions up to 3072 x 2320 pixels under software control, and transmitted for conferencing or stored in the database using JPEG compression. Each image is stored with associated information, text notes, annotations, and a "thumbnail" image. The stored information may be searched for matching images, for example representative images of a particular disease for training, or images to be reviewed for a particular patient. Images may be transmitted with all associated information between sites which have telephone service, worldwide. Support is being added for LAN use with a multi-user database, ISDN and Switch56 communications, and remote microscope control. Interactive conferencing allows rapid transmission of low resolution images for specimen scanning, viewing of multiple high resolution still images, and real-time interactive pointers for detailed discussions of image features. The ImageManager is being used and evaluated for conferencing and training purposes. A study was performed by Roche Biomedical Laboratories to compare the ability of pathologists to make a diagnosis on complex cases using transmitted images vs. routine microscopic examination. The effectiveness of the system in providing images of a sufficient quality to allow diagnosis in a private practice setting will be presented.

Computer Communication Networks↗
PubMed2003

A computer-aided digital audio recording and encoding system for improving the encoding of verbal reports.

The increasing use of verbal reports in psychological research requires tools for improving the ease and reliability of collecting and coding verbal report data. An approach is described that maintains the verbal report data in digitally recorded audio form throughout the collecting and encoding processes. A new computer-aided encoding tool, CAPAS, is described, which randomly selects and plays individual protocol segments and stores computer keyboard-entered codes in an SPSS-formatted data file.

Data Collection↗
PubMed1996

Use of personal computers and digitized film angiograms to produce subtraction angiograms.

Digitization of film angiograms for subtraction purposes alleviates many of the problems associated with conventional film subtraction techniques. In this method, conventional film angiograms are digitized with a laser digitizer. An unenhanced image is subtracted from a contrast material-enhanced image with image processing software and a personal computer. Image registration and the contrast of the subtraction mask image are adjusted as necessary to obtain complete subtractions. Subtraction images produced with this method are superior to subtraction images produced with conventional film subtraction techniques; all areas and densities of a digitized subtraction image exhibit nearly perfect subtraction. Digitized film angiograms and image processing software provide a useful alternative to traditional techniques for producing subtraction angiograms. Digital film subtraction provides more control over image registration, eliminates the need for an intermediate subtraction mask image, and allows the user to control the contrast, window width, and window level of the final image.

Angiography, Digital Subtraction↗
PubMed1982

Intravenous arteriography using digital subtraction techniques.

The application of digital computers to electronic x-ray imaging devices has rejuvenated interest in the field of intravenous arteriography. By utilizing computer image subtraction techniques, digital roentgenographic systems based on fluoroscopy or computed tomography (scanned projection radiography) provide significantly improved vascular imaging compared with conventional film subtraction methods. Digital subtraction angiography schemes isolate contrast media in the vessel by detecting differences in images obtained before and after the injection of contrast medium or changes in the relative attenuation of contrast media at different x-ray energies. Present applications include carotid and peripheral arteriography, thoracic and abdominal aortography, pulmonary arteriography, and ventriculography. Future applications may include intracerebral and coronary arteriography. These systems should provide low-risk outpatient screening arteriography.

Angiography↗
PubMedDate not supplied

The hepatic transport of taurocholic acid in the rat: development of a mathematical model.

1. The transport of taurocholic acid from portal blood to bile was studied in the anaesthetized rat by injecting a radiolabelled pulse of bile acid. 2. The transport process was very rapid, 50% of the dose being secreted within 5 min, and the total dose within 15 min. 3. The transport process had a large capacity. The secretory profile was little modified by a 500-fold increase in the injected dose. 4. The transport process was modelled with both analogue and digital computers. The simplest model which fitted the data comprised rapid uptake from portal blood, slow transport across the cell and rapid secretion into bile. The digital computer simulation suggested that this model is not unique, but will require further testing.

Animals↗
PubMed1998

Structure, use, and validation of the IEUBK model.

The potential impact of the effects of lead in children is a major concern. Although measurements of lead concentration can be made in a geographic area, it is difficult to predict the effects of this exposure that involve complicated biologic functions. Dynamic mathematical models that can be simulated on a digital computer provide one method of analysis to facilitate the prediction process. The integrated exposure uptake biokinetic (IEUBK) model is a dynamic mathematical model that has been discretized for execution on a digital computer. This paper is concerned with the general difficulties in validating a dynamic model of this type. A number of the general pitfalls of validating a model of this type are presented. The illustrations are of a general nature not requiring an understanding of the physiologic effects of lead on children. The concept of validating a model by comparing results to historical data is discussed. A comparison is made with traditional modeling efforts having this form of dynamic model. Also included are general mathematic concepts illustrating potential difficulties with intuitive analyses in calibrating a dynamic model.

Animals↗
PubMed1982

Impedance loading servo pump system for excised canine ventricle.

To investigate ventricular-arterial system interaction, we have developed a hybrid-computer-controlled impedance loading servo pump system that enables us to impose a simulated arterial hydraulic impedance on an excised canine ventricle. An analog computer programmed to simulate a three-element Windkessel model of the arterial system computes instantaneous aortic flow from the instantaneous ventricular pressure. The time integral of this flow is used to command a volume servo pump system that controls the instantaneous ventricular volume. All parameter values in the loading system are controlled by a digital computer. The actual impedance spectrum generated by the system was reasonably close to that expected from the arterial model. The unique features of this system are the following. 1) The instantaneous volume of the ventricle, which is crucial information, can be measured. 2) If needed, the arterial impedance model can easily be reprogrammed to generate more complex impedance spectra. 3) The vascular parameters can be made nonlinear or time varying through the digital computer control.

Animals↗
PubMed1991

Utilizing lung sounds analysis for the evaluation of acute asthma in small children.

One of the most difficult aspects of management of acute asthma in the small child is the clinician's inability to quantitate the response or lack of response to bronchodilator agents because of the inability of a child this age to perform objective lung measurements in the acute state. The present study was designed to evaluate bronchodilator responsiveness in children between 2 and 6 years of age with wheezing by means of a computerized lung sound analysis, computer digitized airway phonopneumonography. Children between ages 2 and 6 who were experiencing acute exacerbations of asthma were included in this study population. The 43 children were evaluated by physical examination, pulmonary function testing, if possible, by use of (spirometry or peak flow meter) and transmission of lung sounds to a computer using an electronic stethoscope to obtain a phonopneumograph with sound intensity level determinations during tidal breathing. A control group of 20 known asthmatic patients between the ages of 8 and 52 years who also presented to the office with acute asthma were evaluated similarly. In each of these individuals, a physical examination was followed by complete spirometry as well as computer digitized airway phonopneumonography recordings. Following initial measurements, all patients were treated with nebulized albuterol (0.25 mL in 2 mL of saline). Five minutes after completion of the nebulization all patients were reexamined and repeat pulmonary function tests were performed followed by CDAP recordings. In the study group of children, the mean pretreatment sound intensity level was 1,694 (range 557 to 4,950 SD +/- 745).(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗
PubMed2000

Quantitative assessment of angiogenesis and tumor vessel architecture by computer-assisted digital image analysis: effects of VEGF-toxin conjugate on tumor microvessel density.

Tumor growth is angiogenesis dependent. As a consequence, strategies aimed at disrupting this mechanism are heavily investigated. Several angiogenesis assays are used to directly compare the efficacy of anti-angiogenic compounds. However, objective assessment of new vascular growth has been difficult to achieve. The aim of this study was to test and develop a computer-assisted image analysis method that would give an unbiased quantification of the microvessel density. Human tumors were grown in athymic mice and tumor biopsies were taken after a weeklong treatment with VEGF-toxin conjugate. Frozen tumor sections were prepared and stained with PE-conjugated anti-CD-31 antibodies and vessels were imaged with a fluorescence microscope. Vessel density was analyzed by quantifying PE-positive pixels per recorded field. In addition, images were further processed to investigate morphological differences by an automated binarization and skeletonization protocol. This procedure allowed the computer-assisted estimation of important angiogenic parameters such as total vessel number, length, and branch points. Based on these indices, differences in the angiogenic response between control tumors and those treated with VEGF-toxin conjugate were readily detected (P < 0.007 for all parameters). More importantly, computer-generated measurements correlated well with manual microvessel counts and showed significantly less variation. Our results suggest that computer-assisted image analysis represents a rapid, objective, and alternative method for the quantitative assessment of tumor angiogenesis and vessel architecture.

Adenocarcinoma↗
PubMed1984

An electronic device for accurate quantification of neuronal mass activity based on a digital integration method.

Quantification of different kinds of neuronal mass activity was performed using an integrative method. For this purpose an electronic device was designed and constructed which is based on a fully digital approach. High precision of the method and an easy way to interface with a digital computer are the advantages of this strategy when compared to other techniques. Performance of quantification and the possibility of the universal use of the device are demonstrated by two examples. (1) Quantitative analysis of whole nerve bundle activity is demonstrated in the case of phrenic nerve mass activity. (2) The usefulness of the digital integrator is further verified in quantification of theta waves of the human EEG as a rather different field of application. In addition, the device is valuable as a tool for the analysis of EMGs. The described digital integrator has many advantages compared to conventional analog integrators, such as autorange feature, very high dynamic range, excellent long-term stability, in principle unlimited integration times and interface capability to a digital computer; it avoids all problems associated with the application of high-impedance integrator operational amplifiers.

Electroencephalography↗
PubMed1998

What's new in mammography.

Early diagnosis of breast cancer plays the leading role in reducing mortality rates and improving the patients' prognosis: mammography is the most sensitive technique currently available for the detection of nonpalpable lesions and therefore the method of choice. However, mammography has some limitations and the technique must be improved with technological devices without affecting image quality. This could be the target to increase diagnostic accuracy. Mammography sensitivity and specificity are now improved with the digital computer assisted technique, teleradiology, digital tomosynthesis or digital angiography--used to study microvascularization--3D imaging or synchrotron light, and laser mammography. Such other technological devices as Mammospot reduce breast thickness and provide better breast compression. Digital mammography can be carried out with film or direct digitization. The advantages of the digital technique are a shorter examination time, less storage space, electronic image recording, with image 'adjustments' made by the radiologist, and especially computerized analysis. The computer aided diagnosis can be defined as the diagnosis made by the radiologist who considers the results of computerized analysis as a 'second opinion'. In this way incidental mistakes made by radiologists, can be corrected by the computer analysis. Computers are a basic element also in teleradiology, which needs immediate and simultaneous admittance to the patient's history and permits radiology optimization in rural areas too. As for tomosynthesis, it permits to study a single slice of the breast without glandular tissue overlapping, which is useful in dense breasts where the diagnosis can be made with a lower X-ray dose. Moreover, this method fits the current mammographic systems easily. 3D imaging is still a work in progress. Synchrotron mammography is used only on surgery specimens, where it exhibits high resolution and contrast, depicting structures and details missed by conventional mammography. Breast DSA allows the study of vessels < 0.20 mm in diameter and of fine microvascular details; it can also demonstrate neoangiogenesis. Laser mammography permits bilateral examinations of the breast in 10-15 mins and is currently used also for breast cancer therapy, although only in animal trials. To conclude, after reviewing new techniques and evaluating the real cost/benefit ratio for each of them, conventional mammography remains the most sensitive tool for breast cancer diagnosis.

Angiography, Digital Subtraction↗
PubMed1988

Quantification of absolute luminal diameter by computer-analyzed digital subtraction angiography: an assessment in human coronary arteries.

Determination of absolute lumen diameters has been shown to be useful in predicting the functional importance of a coronary stenosis. In this study, both single-plane and orthogonal biplane digital subtraction angiograms were obtained in human cadaver coronary arteries. A single absolute diameter was calculated at the site of greatest narrowing in 20 segments by two automated computerized algorithms. Minimum and maximum diameters at the site of the stenosis were measured from pathologic sections prepared after pressure fixation. Method 1, which determines the edges by means of the first derivative of the videodensity curve, derived absolute diameters that fell between the pathologic minimum and maximum in 10 of 20 segments. Method 2, which determines the edges by an average of the first and second derivatives of the videodensity change, derived absolute diameters that fell between the pathologic minimum and maximum diameters in 15 of 20 segments. Method 1 correlated well with the maximum pathologic diameter (r = .76) and less well with the minrmum pathologic diameter (r = .67). Method 2 correlated very well with the maximum pathologic diameter (r = .79) and also correlated well with the minimum pathologic diameter (r = .74). As would be expected, the computerized algorithms tended to overestimate the minimum pathologic diameter and to underestimate the maximum pathologic diameter. In six segments, two orthogonal views were analyzed; no further accuracy was discernible over single-plane determinations. Thus quantitative coronary angiography by digital subtraction angiography is sufficiently accurate to be of use in the measurement of the severity of a coronary stenosis.

Coronary Angiography↗
PubMed1976

Qualitative and quantitative EEG in psychotic children.

The EEGs of hospitalized psychotic boys were analyzed quantitatively by means of visual evaluation, analog frequency analysis, and digital computer period analysis and were compared with those of age- and sex-matched normals. Visual evaluation of the records demonstrated that psychotic children have significantly more beta activity as well as fewer alpha bursts than normal controls. EEG analog frequency analysis showed that psychotic children have a greater percentage of total voltage in the 3-5 cps and 13-33 cps bands, while they show less voltage in the 6-12 cps bands as compared with normal controls. Digital computer period analysis demonstrated more slow, less alpha, and more fast activity, as well as a greater average frequency and frequency deviation in both the primary wave and first derivative measurements in psychotic children than normals, while normals showed a trend towards higher amplitude and amplitude variability. The similarity of the EEG differences between psychotic and normal children to those differences observed between adult chronic schizophrenics and normals, as well as to those between children of "high risk" for becoming schizophrenic and controls, suggests that the above described findings are characteristic for the pathophysiology of schizophrenia.

Adolescent↗