Anastomosis of skin collagen fibrils
Başlık:
Anastomosis of skin collagen fibrils
Yazar:
Starborg, Tobias, author.
ISBN:
9780355978070
Yazar Ek Girişi:
Fiziksel Tanımlama:
1 electronic resource (193 pages)
Genel Not:
Source: Dissertation Abstracts International, Volume: 76-08C.
Özet:
The mechanical strength of animal tissues is dependent on the production of long collagen fibrils, which are the principal source of tensile strength of the extracellular matrix (ECM). The fibrils, which have undetermined lengths, occur in skin in bundles containing several hundred fibrils. Recent work has discovered that collagen fibrils are created as short precursor fibrils that undergo end-to-end fusion to generate the large fibrils seen in older tissues. The work in this thesis tested the hypothesis that inter-fibrillar fusion might not be restricted to end-to-end fusion, but that other fusion events might occur. Individually dispersed fibrils were examined using scanning transmission electron microscopy (STEM), to obtain quantitative data, and skin fibrils in situ were examined using conventional EM. The work has found an important developmental stage at 6-8 weeks in mouse growth where the skin fibrils change from being uniform in diameter to exhibiting non-uniform shafts. This period coincided with a rapid increase in skin collagen content. Analysis of collagen fibrils in cross-section (using conventional embedding and sectioning techniques) and quantitative STEM (of individual fibrils) indicated that at 6-8 weeks of development short early fibrils fuse to the side of existing (long) fibrils. Further studies showed that this was the start of an extensive process of tip-to-shaft fusion whereby the tips of fibrils fuse to the shafts of fibrils to generate extensive anastomosing networks of collagen fibrils. Anastomoses were most evident in 12-week skin, and were virtually absent in earlier tissues. Closer investigation showed that at the site of anastomosis one shaft often tapered immediately adjacent to the region of contact. This indicated that the anastomoses were formed by the fusion of a fibril tip with the shaft of a separate fibril. Therefore, two fibrils anastomosed rather than one fibril branched into two shafts. Further investigations indicated that the small leucine rich proteoglycans had a role in controlling the rate of interfibrilllar fusion. Fibrils extracted from the skin of decorin, fibromodulin or decorin-fibromodulin knockout mice exhibited a reduced rate of anastomosis formation and an increased rate of fibril bulging. These new findings of fibril fusion in skin have been complemented by the use of cultured fibroblasts, which, like fibroblasts in skin, demonstrated the formation of anastomosing fibrils. The cell culture system offers new opportunities to study the molecular and structural basis of fibril anastomosis. The controlled fusion of collagen fibril tips to shafts generates an interconnected network of fibres, which presumably enhances the mechanical strength of the tissue.
Notlar:
School code: 1543
Tüzel Kişi Ek Girişi:
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Yer Numarası | Demirbaş Numarası | Shelf Location | Lokasyon / Statüsü / İade Tarihi |
---|---|---|---|
XX(683843.1) | 683843-1001 | Proquest E-Tez Koleksiyonu | Arıyor... |
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