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Biomedical subjects

K Doi

Publications and source records attributed to K Doi.

At least 613 records · Page 34Linked to original sources
PubMed1990

Automated tracking and computer reproduction of vessels in DSA images.

We are developing an automated vessel-tracking method based on the double-square-box region-of-search technique, for efficient tracking of the connected vascular tree in a digital subtraction angiography (DSA) image. Tracking points and branch vessels are located by searching of the perimeter of boxes, which are centered on previously determined tracking points. The most accurate results (90% true-positive rate with six false-positives per image) are obtained by tracking using the double-square-box method. In relatively straight regions of vessels, a large box is employed for efficient tracking; in curved regions of vessels, a small box is employed to ensure accurate tracking. When tracking is completed, accurate vessel information, ie, the vessel position, size, and contrast determined at each tracking point, is available for further quantitative analysis. Computer reproductions of tracked vessel trees appear to correspond well to those in DSA images.

Angiography, Digital Subtraction↗
PubMed1990

Improvement in radiologists' detection of clustered microcalcifications on mammograms. The potential of computer-aided diagnosis.

Relatively simple, but important, detection tasks in radiology are nearing accessibility to computer-aided diagnostic (CAD) methods. The authors have studied one such task, the detection of clustered microcalcifications on mammograms, to determine whether CAD can improve radiologists' performance under controlled but generally realistic circumstances. The results of their receiver operating characteristic (ROC) study show that CAD, as implemented by their computer code in its present state of development, does significantly improve radiologists' accuracy in detecting clustered microcalcifications under conditions that simulate the rapid interpretation of screening mammograms. The results suggest also that a reduction in the computer's false-positive rate will further improve radiologists' diagnostic accuracy, although the improvement falls short of statistical significance in this study.

Calcinosis↗
PubMed1990

Computer-aided diagnosis in chest radiology.

Digital radiography offers several important advantages over conventional systems, including abilities for image manipulation, transmission, and storage. In the long term, however, the unique ability to apply artificial intelligence techniques for automated detection and quantitation of disease may have an even greater impact on radiologic practice. Although CAD is still in its infancy, the results of several recent studies clearly indicate a major potential for the future. The concept of using computers to analyze medical images is not new, but recent advances in computer technology together with progress in implementing practical digital radiography systems have stimulated research efforts in this exciting field. Several facets of CAD are presently being developed at the University of Chicago and elsewhere for application in chest radiology as well as in mammography and vascular imaging. To date, investigators have focused on a limited number of subjects that have been, by their nature, particularly suitable for computer analysis. There is no aspect of radiologic diagnosis that could not potentially benefit from this approach, however. The ultimate goal of these endeavors is to provide a system for comprehensive automated image analysis, the results of which could be accepted or modified at the discretion of the radiologist.

Breast Diseases↗
PubMed1990

Fundamental study on the mechanism of DNA degradation in tissues fixed in formaldehyde.

The mechanism of DNA degradation and its clinical applications were examined. When purified lambda phage and extracted liver DNA were fixed in phosphate buffered formaldehyde, the DNA did not degrade, but there was incomplete digestion with endonuclease. Rat liver tissues were fixed under various conditions and DNA extracted. Immediate fixation with buffered formaldehyde at low temperature, or the addition of EDTA to buffered formaldehyde blocked the DNA degradation. Analysis of pulsed field gel electrophoresis also showed that DNA was degraded before extraction. These results suggest that tissue nuclease has an important role in DNA degradation in tissue. Furthermore, formaldehyde fixation at low temperature, which may take time and which decreases slightly the staining capacity, is useful for the extraction of intact DNA. For clinical application, the detection of provirus was examined. Genomic DNA was extracted from a necropsy sample of adult T cell leukaemia fixed in formaldehyde; human T cell leukaemia virus type-I (HTLV-I) provirus was successfully detected by Southern blotting.

Animals↗
PubMed1990

Pulmonary nodules: computer-aided detection in digital chest images.

Currently, radiologists fail to detect pulmonary nodules in up to 30% of cases with actually positive findings. Diagnoses may be missed due to camouflaging effects of anatomic background, subjective and varying decision criteria, or distractions in clinical situations. We developed a computerized method to detect locations of lung nodules in digital chest images. The method is based on a difference-image approach and feature-extraction techniques, including growth, slope, and profile tests. Computer results were used to alert 12 radiologists to possible nodule locations in 60 clinical cases. Preliminary results suggest that computer aid can improve the detection performance of radiologists.

Adult↗
PubMed1990

Quantitative computer-aided analysis of lung texture in chest radiographs.

The authors describe a computerized method to quantify and characterize interstitial diseases by using physical texture measures obtained from an analysis of the power spectrum of lung textures in digital chest radiographs. They compared these texture measures obtained from standard radiographs from the International Labour Office (ILO) classification scheme and the ILO classification categories for small opacities in pneumoconioses. Their preliminary results indicate that texture measures obtained from this computer analysis of the ILO standard radiographs correspond closely with the ILO classification categories.

Computer Graphics↗
PubMed1990

Potential usefulness of an artificial neural network for differential diagnosis of interstitial lung diseases: pilot study.

An artificial neural network approach was applied to the differential diagnosis of interstitial lung diseases. The neural network was designed to distinguish between nine types of interstitial lung diseases on the basis of 20 items of clinical and radiographic information. A data base for training and testing the neural network was created with 10 hypothetical cases for each of the nine diseases. The performance of the neural network was evaluated by means of receiver operating characteristic analysis. The decision performance of the neural network was high; it was comparable to that of chest radiologists and superior to that of senior radiology residents. The preliminary results strongly suggest that the neural network approach has potential utility in the computer-aided differential diagnosis of interstitial lung diseases.

Computer Simulation↗
PubMed1990

Electrocardiographical findings of WBN/Kob rats.

Electrocardiographical (ECG) investigations were carried out on 4 and 12 week old WBN/Kob and Wistar male rats. In comparison with Wistar rats which showed ECG findings typical of those of normal rats, WBN/Kob rats showed significantly larger QRS complex amplitude, smaller T wave amplitude, longer QRS duration, and longer QT interval at 4 weeks of age. This tendency became clearer at 12 weeks of age. There were no changes in serum inorganic ion concentrations or cardiac histopathology suggestive of these ECG changes in WBN/Kob rats. These ECG findings in WBN/Kob rats are considered to be a hereditary characteristic of the strain.

Age Factors↗
PubMed1990

Glomerular lipidosis in a Syrian hamster of the APA strain.

Spontaneous glomerular lipidosis was found in a 12-week-old male Syrian hamster of the APA strain. Lipids in the glomeruli were observed as droplets in a prominently expanded mesangial area and as emboli in a dilated capillary lumen. Lipid deposition was also, but less often, detected in tubular epithelial cells and interstitial cells around the lipid-laden glomeruli. This case of glomerular lipidosis was considered to be closely related to hyperglycaemia and hyperlipidaemia.

Animals↗
PubMed1990

Histochemical study on the bile duct system of normal rats.

The bile duct system of normal rats was examined histochemically. Although the apical surface of biliary and glandular epithelial cells was positively stained with Concanavalia ensiformis (Con A), Dolichos biflorus (DBA), Glycine max (SBA), Ulex europeus-I (UEA-I) and Triticumvulgaris (WGA), the cytoplasm did not apparently react with any lectins. Therefore these cells might not play an important role in an active secretion of mucin. On the other hand, the cytoplasm of goblet cells was positively stained with periodic acid-Schiff, high iron diamine, Con A, DBA, Griffonia simplicifolia-II (GS-II), SBA, UEA-I, and WGA. This suggests that mucin secreted from the goblet cells may be acid one with sulfonic terminals.

Animals↗
PubMed1990

Evaluation of radiographs developed by a new ultrarapid film processing system.

The image quality of radiographs developed by a new ultrarapid processor was evaluated to determine if faster processing causes degradation in the image. The processor used was the Konica Super-Rapid SRX-501 model. Two films designed for this processor (Konica MGH-SR and MGL-SR) were processed in 45 sec and were compared with standard rapid processing in 90 sec of corresponding conventional films (Kodak TMG and OC). Rare-earth screens (Kodak Lanex Regular and Lanex Medium) used with the new and conventional films interleaved during angiographic studies or for phantom images were assessed for image quality. The basic imaging properties of the screen-film systems were examined by measuring (1) Hurter and Driffield curves, (2) modulation transfer functions by using the slit method, and (3) noise Wiener spectra. Subjective clinical assessment showed that the images obtained with ultrarapid processing were acceptable, with increased contrast and graininess. Hurter and Driffield curve measurements confirmed higher gradients. Modulation transfer function measurements were the same as for the conventional films. Noise Wiener spectrum measurements showed a 10% increase in noise for MGH-SR vs TMG film and a 30% increase for MGL-SR vs OC film. We conclude that acceptable image quality can be obtained using ultrarapid processing, with processing time approximately 60% that of conventional rapid processing. Potential applications include all areas in which rapid availability of the radiograph for interpretation is important. Although the processor studied was the first of its kind available, our evaluation indicates that the technology is available for a new class of ultrarapid processors.

Evaluation Studies as Topic↗
PubMed1990

[Three-mode factor analysis of emblematic gesture and body manipulation viewed from the dorsal perspective].

This paper focuses on emblematic gesture and manipulation of body movements. Subjects viewed from the dorsal perspective the body movements displayed by two actors/actresses. These movements depicted the ten emotions of affection, joy, surprise, fear, sadness, disgust, anticipation, anger, contempt and acceptance. Three-mode factor analyses were applied to the data. Three factors were found in the emotion-mode, three in the scene-mode, and two factors in the subjects-mode. The emotion-mode and scene-mode factors were found to correspond to a high degree. Factor I was interpreted as an acceptance dimension, including affection, joy, anticipation and acceptance. The typical emblematic gestures were displayed with a standing posture and advanced movement. Factor II was interpreted as an avoidance dimension, including surprise, fear and sadness. The typical emblematic gestures were divided into two movements; regressive and "shrinking down". In addition, self-attached manipulations were typical expressions of sadness. Factor III was interpreted as a rejection dimension, including disgust, anger and contempt. Considerable body manipulation was used to express these emotional categories. Core-matrix and subjects' factor scores were correlated with a response tendency in terms of subjects' evaluations rather than their accuracy of judgment.

Adult↗
PubMed1990

Antihypertensive effect of tryptic hydrolysate of milk casein in spontaneously hypertensive rats.

1. Repeated oral administrations of tryptic hydrolysate of bovine milk casein (CEI) showed antihypertensive effect in spontaneously hypertensive rats. 2. Single oral administration of CEI antagonized the pressor response to angiotensin I. 3. Bovine milk casein hydrolysate inhibited the angiotensin I-converting enzyme (ACE) activity. Three peptides with ACE-inhibiting activity were isolated from CEI. 4. It is suggested that ACE-inhibiting peptides in the tryptic hydrolysate milk casein are absorbed from the intestinal tract and produce an antihypertensive effect.

Administration, Oral↗