Computer graphics analysis of stresses in blood flow through a prosthetic heart valve.
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The full graphic capabilities of a minicomputer have been applied to rapid and versatile analysis of long-term electrocardiographic tape recordings. Interfaced to a standard Avionics tape analyzer, the system's multiple display options provide a powerful tool for arrhythmia detection in a reasonable amount of time. Detection accuracy of the system compares very favorably with previously published figures for computer EKG monitoring. Quantitation of arrhythmic beats is an integral feature of the tape scanning. A method for analog display of randomly selectable EKG complexes is also described.
Mandibular movements can be represented and viewed graphically in three planes--occlusal (approximately horizontal but variable), sagittoid (approximately sagittal), and frontal. The student of occlusion can vary the settings of the mathematical articulator and observe the three-dimensional changes produced in the interocclusal movement patterns.
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Most of the available methods for preparing professional slides to be used in oral presentations can be cumbersome, time-consuming, and expensive. Creating high-quality 35-mm slides may require the use of expensive medical illustrators and photographic equipment not available to all physicians. More recently, technology has emerged that permits professional in-office generation of quality slides using commercially available computer graphics software and film recorders. Such a system is simple to establish and maintain when compared with commercial slide production facilities. We will review the hardware requirements of such a system, as well as the advantages and disadvantages of several commercially available software packages. Using a personal computer-based slide-making system, any physician communicating with small or large groups of people can now produce professional-looking slides easily, rapidly, and inexpensively.
This paper describes the setting-up and management of a computer graphics service, mainly for producing 2 x 2 inch projection slides, by a department of medical illustration within a medical school. The service has been arranged to provide a limited facility for composing original illustrations by computer and to encourage medical and scientific staff to compose their own illustrations. These are recorded on magnetic disc for review and possible adjustment by medical illustrators. Images are then output as slides or paper prints by the medical illustration department. The range of equipment and apparatus used is described and evaluated briefly. Also described are the effects of the introduction of a computer-generated graphics service on the general work of non-patient slide production in the department.
This paper discusses the application of the data handling-graphics-statistics program Stata (Computing Resources Center, Santa Monica, CA) to radioimmunoassay. We have found that this program is more powerful and easier to use than a spreadsheet for analyzing various kinds of laboratory data generated from chromatography, radiolabeling experiments, enzyme-linked immunosorbent assays, and radioimmunoassays, to name several examples. Data from a radioimmunoassay procedure, originally analyzed using a spreadsheet, Lotus 1-2-3, have been processed with Stata. Simple programs (batch files) have been devised for computations and graphics. The original data and a comparison of results are presented.
A descriptive medium for the presentation of protein structure has been developed and used to evaluate the structure of the active site of bovine trypsin (EC 3.4.21.4). This technique, involving advanced computer graphics technology, permits the facile display of a representation of the molecular surface of proteins of known structure and employs color to code the structural or chemical features of this surface. Benzamidine derivatives were inserted into the benzamidine-binding site of trypsin and the binary inhibitor-trypsin complex was evaluated by using the computer-generated structure. On the basis of qualitative assessments of the contribution of electrostatic and hydrophobic forces to the binding energy associated with complex formation, we made predictions concerning the effects of interaction of benzamidine substituents and amino acid side chains upon the binding energy associated with inhibitor-protein binding. The computer display of the molecular surfaces of the binary complex of substituted benzamidines and trypsin permitted unique insight into the identity and chemical properties of the atoms that participate at the interface of the molecular surfaces of the inhibitor and the protein. The computer-generated molecular surface display can potentially be combined with quantitative definition of the physical forces involved in the interaction of molecular surfaces. This technology should facilitate the study of the structure-activity relationship of substrates, inhibitors, and drugs that bind to proteins of known three-dimensional structure.
We compared the fingerprint images using a personal computer and a graphic software sold on market. The fingerprints of thumb of left hand recorded by pressing and rolling on paper were input in computer using image scanner. These two fingerprint images were overlapped by moving and rotation on the computer screen, and were fitted well. This result showed that the fingerprints recorded by any way from one person were fitted. Latent and accused's fingerprints were also input in computer using image scanner. These images were analyzed by the same procedure. These two fingerprints were part by unfitting. It was decided these two fingerprints were not derived from one person. We also considered the possibility that the latent fingerprint was the reversed one. Then, the image was reversed of its color on the screen of computer (black to white and white to black) and compared by the same procedure. In this experiment, two fingerprint images were not fitted in a part. This showed that the reversed fingerprint was also able to be analyzed by this procedure. For the comparison of fingerprints, this report showed the ability of the personal computer and software which can be obtained easily from market. Following the improvement of the hardware and software used in this examination in near future, the computerized identification of fingerprints like this study will become more accurate and convenient.
The mucosal blood volume in 20 to 24 different regions of stomach was estimated by reflectance spectrophotometry during endoscopy, and an image showing mucosal blood distribution was made by two-dimensional computer color graphics with the aid of a personal computer. In 55 normal controls, the estimated mucosal blood volume (EMBV) was greater in the corpus mucosa than in the antral mucosa, and less in the lesser curvature than in the greater curvature. The volume in the anterior and posterior walls was almost the same. In 15 patients with active gastric ulcers in the angular region, the EMBV was decreased in all regions in the stomach. In 37 patients with healing ulcers, the EMBV increased, resuming the same levels as in normal controls. However, the EMBV around the ulcer increased remarkably at this stage. In 35 patients with ulcers in the scarring stage, the distribution of the EMBV was similar to that in the normal controls. These hemodynamic changes were shown clearly in a color display with the aid of a personal computer. This method could offer new possibilities in endoscopic research.
The three-dimensional structure of rat liver formaldehyde dehydrogenase (FALDH), previously known as class III alcohol dehydrogenase, was constructed using computer graphics and computer programs developed for model building. The construction is based on horse liver alcohol dehydrogenase (EE-ADH), whose structure has been elucidated by X-ray crystallography. The high sequence homology between the two enzymes makes knowledge-based modelling feasible in this case. The model shows a remarkable similarity to horse liver alcohol dehydrogenase especially in the NAD-binding domain. Certain mutations, and the one insertion in FALDH compared to EE-ADH in particular, have cause important changes in the substrate binding site, and thus aliphatic alcohols have been replaced by hemi-thioacetals as favourable substrates.
Two computer graphics techniques for displaying hydrogen bonds between the main chains of different proteins are described, and illustrated for two thiol proteases. (The X-ray crystallography was performed by Kamphuis et al. in 1984, and by Baker and Dodson in 1980.) One is a three-dimensional model that can be manipulated in space; the hydrogen bonds are represented with the smoothed alpha-carbon plot of the polypeptide chain. In the other type of display, hydrogen bonds are viewed in relation to the one-dimensional sequence. Both types of picture facilitate visualization of hydrogen bond patterns, such that loop motifs, as well as alpha-helices and beta-sheets, can be examined easily. We suggest that such displays are useful as a general means of displaying whole proteins and whole domains because they reveal more information than do conventional simplified pictures of proteins, which focus exclusively on alpha-helices and beta-sheets. These techniques can be implemented on a UNIX-based computer graphics workstation. (UNIX is a trademark of Bell Telephone laboratories.)
The dye Procion brown was used to identify in the light and electron microscope, synaptic contacts made between monosynaptically coupled neurons in the lamprey spinal cord whose synaptic interaction had been recorded. Synaptic contacts were made on different dendrites of the postsynaptic cell at different distances from the soma. Some of the contacts were made on dentritic spines and some on the smooth shaft of the dentrites. Serial sections through synaptic contacts made on dendritic processess of the postsynaptic cells were used for three-dimensional reconstruction of the synapses using computer graphics techniques. The computer reconstructions and detailed examination of the serial EM micrographs revealed the large proliferation of membrane involved in making these en passant synapses as well as the morphological changes due to stimulation of the presynaptic axon. These changes include depletion of synaptic vesicles and formation of complex vesicles and synaptic cisternae. Besides chemical synaptic contacts, four electrotonic contacts were located, confirming the mixed electrochemical synaptic response recorded from the postsynaptic cell. The mean quantum content was estimated and compared with the estimate of the available transmitter pool, assuming the quantal release hypothesis applies at these synapses. The total transmitter pool was estimated by counting all synaptic vesicles in all synaptic contacts. It was estimated that about 6% of the total transmitter pool is available for release at these synapses. This compares with less than 1% at the neuromuscular junction and about 20% at sympathetic synapses. These results support the hypothesis that synaptic vesicles may be recycled as described by Heuser and Reese (22) at the neuromuscular junction. Ongoing studies are investigating the effect on a variety of synaptic junctions to stimulation for different periods of time of presynaptic axons. The methods described in this study can also be used to test the models of synaptic interaction on dendritic trees described by Rall (39) and Jack and Redman (24).
Recent application of computer graphics, using standardized cephalometric analyses, have allowed the surgeon to visualize the predicted surgical outcome on the computer video monitor. Stereolithographic models constructed from digital image data (computed tomography and magnetic resonance) will allow the surgeon to view the external and internal anatomy prior to surgery. This article describes the development of such technology and reports its use in one case.
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