Biomedical subjects
Publications and source records attributed to G Albiser.
A left handed double helix is proposed as a model for C-DNA. This conformation presents geometrical parameters which are in agreement with X-ray data as well as with infrared measurements. Dihedral angles and atomic coordinates are given together with a stereo view. Curves of the calculated diffracted intensities are compared with experimental data.
Different left handed double helices are proposed as models for DNA fibers in the C form. These conformations have geometrical parameters which agree well with fiber X-ray data and the orientations of their phosphate groups are in good agreement with infrared dichroism results. A complete set of atomic coordinates and dihedral angles are given together with curves of calculated diffracted intensities. The present results are compared with experimental values and with the other C-DNA models.
High-angle x-ray diffraction was applied to the study of four meniscal fibrocartilages and 11 articular cartilages from patients suffering from various articular disorders. In eight samples microcrystals were seen, apatite most frequently, CaHPO4 in two instances, calcium pyrophosphate dihydrate (CPPD) in one. These results confirm the association of various crystals in a single joint, and favour their heterogenous partition on collagen fibres.
Two right handed double helices are proposed as models for DNA fibers in respectively the A and the B form. The present conformations have geometrical parameters which agree very well with fiber X-ray and the orientation of their phosphate groups is in good accordance with infrared dichroïsm measurements. Dihedral angles and complete sets of atomic coordinates are given together with stereo-views and curves of the calculated diffracted intensities. Results are compared with experimental data and with preceding DNA models.
A search for a left-handed double helix model for B-DNA fibers has been undertaken. The model has to present good stereochemistry and also to be in agreement with X-ray and infrared data. Dihedral angles as well as atomic coordinates and calculated intensities curves are given for the best model obtained. Comparison with experimental results shows that this model must be rejected as a candidate for the representation of B-DNA fibers.
A right-handed double helix is proposed as a model for fibres of B-DNA. This conformation presents geometrical parameters which are in agreement with X-ray data as well as with infrared measurements. Dihedral angles and atomic coordinates are given together with curves of the calculated intensities. These results are compared with experimental values and with preceding models of the B-DNA.
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An X-ray diffraction study has been undertaken on Human and Rabbit blood-vessels. Vessels are stretched 500% and the diagrams present a great analogy with those obtained from collagen. Thus, it appears, that it is possible to determine by X-Rays some pathological anomalies of the collagen in vessels.
An X-ray diffraction study has been undertaken on fibres of two different DNA compositions respectively corresponding to 42 and 72% of (G-C) base percentages. The fibres were prepared after binding of copper or silver ions to the DNA gels. With a relative humidity of 92%, the B-form has been observed for these two DNA molecules in the presence of copper ions or with a low percentage of silver ion binding. When the silver ion percentage is increased, a new form appears. From the comparison between the experimental and calculated intensities one can note that the proposed binding sites for copper involve few modifications in the X-ray patterns. For the silver, the calculated intensities show that the metal atom is near the double helix axis. For low percentages of silver the site between successive guanine bases cannot be distinguished with certainty by intensity analysis.
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