X-ray diffraction analysis of connective tissue samples, which contain type I and type III collagen shows that twisted collagen fibrils are a general principle of assembly. The occurrence of twisted fibrils in native wet Chordae tendineae, skin and Aorta is combined with a shorter axial periodicity of about 65 nm. This shorter D period is shown to be directly related to the tilt of the molecules, which have to be curved to build-up twisted fibrils.

Adult↗

PubMedDate not supplied

[Structure and mechanical properties of dermatosparactic collagen (author's transl)].

Dermatosparactic calf-tail-tendon-collagen was investigated by mechanical measurements, electron microscopy and x-ray diffraction. We suppose, that the tensile strength decrease of the fibres is due to the irregular aggregation of subfibrils to fibrils. The x-ray diagram of the fibre is not influenced by state of disorder. Cyclic extension of dermatosparactic collagen leads to a higher increase in tensile strength than in the case of normal calf tendon. The effect might be due to the increase of fibril- and area-density resulting in an augmentation of crosslinks.

Animals↗

PubMedDate not supplied

[Trace elements in several organs and mechanical properties of collagen under the influence of D-penicillamin (author's transl)].

The content of trace elements in several organs of rats under the influence of D-penicillamine (D-PA) was investigated by the neutronactivation-analysis. It could be shown an diminution of Cu, and Co under D-PA-treatment, the content of Fe, Mn, Rb and Zn was not influenced. The investigated organs didn't show any submicroscopic alterations under D-PA. On isolated collagen fibrils of tail tendon was seen a significantly diminuition of E-moduls. In accordance with Siegel the principal effect of D-PA is thought to block the synthesis of functional groups from Schiff-base crosslink precursors but not to inhibit lysyloxidase by loss of Cu-ions of connective tissue. The thermostability of D-PA influenced fibrils is changed in stretched state only and will be due to the lack of crosslink Schiff-bases; where as the shrinking point of not stretched fibrils shows only aging dependent changes.

Animals↗

PubMedDate not supplied

[On the determination of changes in the large periodic structure of collagen (author's transl)].

Changes in the large periodic structure of collagen were investigated with the aid of synchrotron radiation. Following results were obtained: 1) Macroscopic extension results in elastic deformation of the elements which are determinant for the structure. 2) The increase of the large period is not proportional to the macroscopic stress. 3) The interpretation of these facts requires a mechanical coupling between the structural units. Up to extensions of 4% this coupling is produced by means of a viscoelastic matrix. 4) In all probability the polypeptide helices are deformed in an inhomogeneous mode. The results were set against measurements on human tendon and on artificially crosslinked collagen. The relations between the mechanical behaviour and the change of the large period were compared with the properties of a mathematical model.

Animals↗

PubMedDate not supplied

[Paracrystals in native collagen (author's transl)].

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Animals↗