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At least 163 records · Page 9Linked to original sources
PubMed1992

HNK-1 expression pattern in normal and bis-diamine induced malformed developing rat heart: three dimensional reconstruction analysis using computer graphics.

The spatiotemporal distribution of the immunoreactivity of monoclonal antibody HNK-1 was investigated immunohistochemically in normal and bis-diamine-induced malformed rat embryonic hearts using three-dimensional reconstruction with computer graphics. First recognized in the primitive heart 11.5 days after conception, HNK-1 immunoreactivity was distributed in the atrio-ventricular and bulbo-ventricular junctional areas with incomplete ring-like appearance in the early embryonic stages. In the late embryonic stages the immunoreactive sites were rearranged and localized in the sites topographically corresponding to almost the entire pathway of the conduction system, including the three major internodal tracts connecting the right sinoatrial node and atrioventricular node. Immunoreactivity gradually decreased after the completion of the conduction system, and only a faint reactivity in the atrio-ventricular node region remained in the new-born heart. These results indicate that HNK-1 is expressed temporarily in the pathways corresponding to the conduction system during the development of the heart. In bis-(dichloroacethyl)-octamethylen-diamine (bis-diamine)-induced malformed hearts, localization of HNK-1 immunoreactivity was not remarkably altered in the early embryonic heart. In the late embryo, immunoreactive sites in the sino-atrial node region and atrio-ventricular node region deviated dorsocaudally with the poorly developed internodal tracts, and abnormal distribution was observed in the bilateral atria. We consider that these abnormalities may occur in conjunction with abnormal morphological development such as insufficient absorption of the sinus venosus.

Animals↗
PubMed1995

Application of computer graphics for assessment of spinal deformities.

A graphical portrayal system to assess spinal deformities is described. The system is based on software to display and manipulate three-dimensional images of the spine and trunk surface. Qualitative measurements of internal spinal alignment and trunk appearance are provided. The graphics display is developed using graPHIGS routines in conjunction with the C programming language and the UNIX operating system. This software provides clinicians with a computer-aided measurement tool that rapidly conveys clear and concise information about the deformities associated with abnormal spinal curvatures.

Computer Graphics↗
PubMed1985

Comparative computer graphics and solution studies of the DNA interaction of substituted anthraquinones based on doxorubicin and mitoxantrone.

1-[[(Diethylamino)ethyl]amino]- and 1,4-, 1,5-, and 1,8-bis[[(diethylamino)ethyl]amino]anthraquinones are shown to intercalate into DNA. Computer graphics modelling of their intercalation into the self-complementary deoxydinucleoside d(CpG) showed differences in binding properties. While the 1-substituted compound can bind from either groove, the 1,8-disubstituted compound binds with both substituents in the major groove. In the low-energy state of the complex with the 1,5-disubstituted compound, this ligand "straddles" the site with a substituent in each groove--to do this, the compound must bind to a non-base-paired region, so inducing base pairing. The 1,4-compound binds from the major groove; "straddling" is also possible if full minimization of deoxydinucleoside geometry is performed. The differences in binding mode and interaction energies are reflected in the affinities of interaction (1,5- greater than 1,4- much greater than 1,8- greater than 1-); also the antiproliferative effects in vitro are in general agreement with this ranking.

Animals↗
PubMed1985

Shape changes and polarization of cells migrating through tissue. A high-voltage electron microscope and computer graphics study of serial thick sections.

Structural changes of carcinoma cells and fibroblasts migrating through small spaces in the elastic-collagen reticulum of mouse peritoneum have been studied by high-voltage electron microscopy of serial thick sections and by computer graphics reconstruction of cell profiles. The change of shape profile of an individual cell, between serial sections is large and the distribution of organelles is very non-uniform and changes markedly between sections. Conclusions about adhesion, intercell contact, cell shape and polarization of cytoplasmic organelles could only be reached by assessing a complete set of serial sections. Our preliminary results suggest that interesting structural changes occur in both carcinoma cells and fibroblasts when migrating through this tissue.

Adenocarcinoma↗
PubMed1984

Computer graphics analysis of sleep-wakefulness state changes after pontine lesions.

The average EEG amplitude, average EMG amplitude and PGO spike rate per one minute epoch were measured for 3 days before and 21 days after pontine lesions in the cat. A trivariate computer graphics display of one baseline day's data (of 1350 epochs) revealed three major clusters of points that were automatically sorted by cluster analysis and corresponded to wakefulness, slow wave sleep and paradoxical sleep. Following combined medial-lateral caudal pontine lesions, the cluster of points that corresponded to the state of paradoxical sleep was absent. Two clusters were still evident and corresponded to wakefulness and slow wave sleep, which was characterized by higher than normal EMG amplitude and PGO spike rate. Whereas medial caudal pontine lesions alone did not reproduce these effects, lateral caudal pontine lesions did. These results suggest that cells and/or fibers located within the lateral tegmental field rather than those within the medial gigantocellular tegmental field of the pons are most important for the generation of the cluster of events that characterize paradoxical sleep.

Animals↗
PubMed1983

The use of computer graphics to find an optimal fit for a human total artificial heart.

The analysis of the thorax and the vessel system adjacent to the heart of different individuals seems to indicate that a fitting of an artificial heart before the operation should be done. A tailoring of the arterial and atrial connectors seems necessary. Computer graphics using CT-scans as a basis render all the required information and a comprehensible view of the vessel system. Future developments should improve the practicability of the system and make use of modern 3-dimensional viewing techniques already there for application.

Computers↗
PubMed1984

Computer graphics modelling and the specificity of renins.

Mouse submaxillary, mouse kidney and human renins have been modelled using the three-dimensional structure of the homologous endothiapepsin, which has been defined by high-resolution X-ray analysis, and the amino acid sequences derived from protein, complementary DNA or gene sequencing. These computer graphics studies have shown that all renins can adopt three-dimensional structures similar to those of other aspartic proteinases with small insertions and deletions at the surface and often at beta-turns. The catalytically essential aspartates lie at the centre of a deep and extended cleft, and differences in the subsites, especially at S3' have been correlated with the known specificities of the renins. The models have shown that various residues on the surfaces of the renins adjacent to the active site cleft may play a part in recognizing and binding angiotensinogen. Reasons for a neutral pH optima have also been suggested.

Amino Acid Sequence↗
PubMed1971

Computer graphics as an aid to learning.

Departing from the traditional model for teaching and learning, this article deals with the problem of teaching and learning the effective application of knowledge already acquired. To this end, a model for the process of exercising judgment was outlined, and the results of an empirical study of judgmental learning were employed to show the inadequacy of the traditional outcome feedback procedures. Computer graphics techniques were used to provide new forms of information to the learner; the results are promising for the rapid learning of a task that would otherwise be difficult to learn.

Cognition↗
PubMed1978

Structure of methemerythrin at 2.8-Angstrom resolution: computer graphics fit of an averaged electron density map.

The crystal structure of methemerythrin from Themiste dyscritum has been determined at 2.8-Angstrom resolution by single isomorphous replacement technique combined with anomalous scattering from a K2HgI4 derivative. Noncrystallographic symmetry relating the four subunits in the asymmetric unit was used to obtain an average electron density map of the hemerythrin monomer, and a computer graphics system was used to fit a polypeptide model to the electron density. The average map was of sufficient quality to locate most of the amino acid side chains and to confirm the assignment of His-25, His-54, Glu-58, His-73, His-77, His-101, Asp-106, and Tyr-109 as the iron ligands. One of the mercury sites in the heavy atom derivative is located between two Cys-9 residues related by a noncrystallographic twofold axis, although no intersubunit disulfide bond is present in the native structure. The residues responsible for the binding of the subunits to form the octamer are identified.

Amino Acids↗
PubMed1990

The role of the vimentin intermediate filaments in rat 3Y1 cells elucidated by immunoelectron microscopy and computer-graphic reconstruction.

The three-dimensional arrangement of vimentin intermediate filaments (IF) was studied in 3Y1, rat fibroblastic cell line, to elucidate its biological role in the cell. While actin filaments were observed exclusively in the superficial part of the cell, vimentin IF were found to be abundantly present in the inside of the cell where microtubules were occasionally discovered. By whole-mount immunoelectron microscopy and computer-graphic reconstruction of serial thin sections, it was observed in more detail that vimentin IF are located very close to the nucleus, endoplasmic reticulum, and mitochondria. Vimentin IF were observed to be attached to these organelles laterally or terminally. Thus, we can reasonably assume that vimentin IF are major cytoskeletal structures deep inside the cell and that they play an important role in supporting the location of the organelles. This is the first report which has visualized the three-dimensional relationship between vimentin IF and the organelles of the cell.

Animals↗
PubMed1988

Color vision testing with a computer graphics system: preliminary results.

We report a method for computer enhancement of color vision tests. In our graphics system 256 colors are selected from a much larger range and displayed on a screen divided into 768 x 288 pixels. Eight-bit digital-to-analogue converters drive a high quality monitor with separate inputs to the red, green, and blue amplifiers and calibrated gun chromaticities. The graphics are controlled by a PASCAL program written for a personal computer, which calculates the values of the red, green, and blue signals and specifies them in Commité Internationale d'Eclairage X, Y, and Z fundamentals, so changes in chrominance occur without changes in luminance. The system for measuring color contrast thresholds with gratings is more than adequate in normal observers. In patients with mild retinal damage in whom other tests of visual function are normal, this method of testing color vision shows specific increases in contrast thresholds along tritan color-confusion lines. By the time the Hardy-Rand-Rittler and Farnsworth-Munsell 100-hue tests disclose abnormalities, gross defects in color contrast threshold can be seen with our system.

Adult↗