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J Woodhead-Galloway

Publications and source records attributed to J Woodhead-Galloway.

11 recordsLinked to original sources
PubMed1978

Low angle X-ray diffraction studies on stained rat tail tendons.

Low angle X-ray diffraction patterns of rat tail tendons with heavy metal stains added were examined to help clarify the effects of fixation and staining on collagen fibrils. Fixing and staining of rat tail tendon fibers gives an X-ray pattern with an intensified 3.8 nm row and the preservation of most equatorial features found in the native pattern. The presence of the native pattern features suggests the value of fixation in preserving native structure before staining. Staining of rat tail tendon fibers without prior fixation led to the disappearance of the native equatorial features and the appearance of a new broad row line corresponding to a spacing of around 10.0--17.5 nm. This observation suggests that some alteration has taken place in the native structure and may be related to electron microscopic observations of units of 10.0--20.0 nm in collagen fibrils under some disruptive or developmental conditions.

Animals↗
PubMed1976

Amianthoid change: orientation of normal collagen fibrils during aging.

High-angle x-ray diffraction provides direct evidence that amianthoid change, occurring during aging of costal cartilage, corresponds to a transformation from an isotropic to a marked anisotropic distribution of collagen fibrils. Low-angle x-ray diffraction and electron microscopy show that the fibrils have the customary 67-nanometer axial periodicity. Electron microscopy shows that wide amianthoid collagen fibrils consist of smaller parallel fibrils fused together. Similarities between amianthoid change and tendon morphogenesis are briefly discussed. Amianthoid change is remarkable in that aging is accompanied by increased order.

Aging↗
PubMed1976

The chitin crystallite in arthropod cuticle.

Electron microscopy has revealed that chitin from a representative selection of insect orders (plus one crustacean and one arachnid) is localized in crystallites about 2.8 nm across. Furthermore, these crystallites are arranged on an hexagonal or pseudo-hexagonal lattice, the lateral order of which varies considerably. The lattice becomes secondarily reoriented during cuticle expansion following an ecdysis. The size of the 'unit cell' has been measured both by optical diffraction and direct measurements of the micrographs, permitting an estimate of the chitin and resilin content for locust rubberlike cuticle. The number of poly-N-acetyl-glucosamine chains per sheet and sheets per crystallite can be estimated from the physical dimensions of the crystallite. Each crystallite is unlikely to comprise more than 3 sheets and 6 chains per sheet. The calculated and measured density of alpha-chitin can be shown to be in close agreement.

Animals↗