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Biomedical subjects

R F Dyer

Publications and source records attributed to R F Dyer.

At least 19 recordsLinked to original sources
PubMed1979

The histomorphology of the elastic tissue system in the skin of the human hand.

This study compares the effectiveness of the Verhoeff and Puchtler-Sweat resorcin fuschin methods of staining the elastic tissue of palmar and dorsal skin specimens of the human hand. The resorcin stain demonstrates the "oxytalan" fibres of the elastic tissue system in the dermal papillary layer of the palmar skin. Oxytalan fibres are not generally demonstrated by the Verhoeff method and are not demonstrated in the dorsal skin specimens. These studies substantiate the existence of a system of elastic tissue fibres in the skin of the hand. The inter-relationship of the elastic and collagenous fibres appears to complement each of their functions; namely, in anchoring the dermo-epidermal junction, absorbing the stresses of stretch and compressive forces and return the tissues to their original state of tension, and providing protection to the dermal appendages in addition to lending a gradient mobility transmitted through the dermis to the subcutaneous layer to give suppleness and mobility to the skin.

Adult↗
PubMed1978

Endoneurial mast cells in peripheral nerves of the armadillo dermis.

Electron microscopy of the dermis of the 9-banded armadillo, Dasypus novemcinctus, reveals an intimate relationship of mast cells to peripheral nerves. Mast cells are routinely found in the dermis in close proximity to nerves, and mast cells are also present within the perineurial cell sheath in the endoneurial space proper. These cells contain electron opaque granules and exhibit numerous surface folds as is characteristic of other species. The degranulation of the mast cells by injection of 0.5% aqueous trypan blue reveals sequential exocytosis of granules, similar to that described for the rat. Degranulation occurs in most dermal and endoneurial mast cells following a single intradermal injection of trypan blue. A small number of mast cells partially degranulate and a few exhibit no degranulation, suggesting a heterogeneous population. It is also noted that mitochondrial morphology differs in degranulating cells, in that they become swollen and vacuolated. The results of this study are discussed in light of previous results reported for other species, mainly at the light microscope level.

Animals↗
PubMed1977

Intracellular collagen in the nonpregnant and IUD-containing rat uterus.

An experiment designed to study the effects of the copper IUD on the virgin rat uterus has revealed the presence of intracellular collagen fibrils in control uteri and in uteri that have contained a copper IUD for three months. The cells containing the collagen are found in the stroma in close proximity to the uterine epithelium. The collagen is found within membrane-bound cytoplasmic vacuoles that vary in morphology. In some cases the fibrils are tightly packed and linear, with no other material evident in the vacuole. In other examples, the fibrils are randomly arranged and the vacuoles contain a punctuate material which is characteristic of phagolysosomes. Finally, cytoplasmic vacuoles are seen which contain ill-defined debris and poorly-visualized structures that exhibit a periodicity, suggesting a terminal phase of fibril breakdown. All animals were sacrificed in metestrus, and the results indicate that intracellular collagen is present in the nulliparous rat uterus at this stage of the cycle. In addition, this phenomenon does not appear to be influenced by the presence of a copper IUD over a period of three months.

Animals↗
PubMed1977

Morphologic analysis of tympanic membrane grafts.

Many materials are presently used for repair of tympanic membrane defects. Since the microscopic organization of these tissues may play a role with respect to the suitability of replacement of one with the other, a comparative electron microscopic study of temporalis fascia, fresh and preserved amniotic membrane was undertaken. An effort was made to determine the similarities and differences of these tissues and our clinical experience with their use is presented.

Amnion↗
PubMed1976

Ultrastructural features of adult human tendon.

A variety of human tendons have been studied at the electron microscope level. The fibers of these tendons are composed of collagen fibrils that average 1,750 A and 600 A in diameter. A third population that measures 100 A in diameter may represent immature collagen or filaments that are incorporated into tendon elastic fibers. The larger collagen fibrils vary in ratio with respect to one another, and are connected by interfibrillar bridges which in some cases appear to extend through the substance of the fibril. The collagen fibrils of the paratenon are less-well organized than those of the tendon proper and average 600 A in diameter. Tendons that exhibit the property of lateral stretch (plantaris and palmaris) were compared at the ultrastructural level with tendons that do not have this property. No differences between the two tendon types could be determined in normal or spread preparations, indicating that the differences in physical characteristics are a result of fiber rather than fibril organization.

Adult↗
PubMed1976

Tendon plasticity-a property applicable to reconstructive surgery of the hand.

A study carried out by light and electron microscopy of the behaviour of different tendons when subjected to lateral stretching and longitudinal splitting. Tendons like the FDS are more resistant to lateral stretching and show greater shredding. The structure of the tendon shows criss-crossing of the fibrils, necessary to stand up to the greater stress to which the tendon is normally exposed.

Biomechanical Phenomena↗
PubMed1975

Ultrastructure of keloid: an unusual incident involving lepromatous leprosy.

A patient with lepromatous leprosy developed keloids on the dorsum of both arms in response to ulcerations due to acute erythema nodosum leprosum reactions. Electron microscopic examination of the keloidal dermis showed a morphology indicative of increased production of normal collagen fibrils. The greatest cellular changes from normal were in fibroblasts which were enlarged due to increased amounts of rough endoplasmic reticulum and extensive Golgi complexes. Nuclear folds were also evident in these fibroblasts. Some cells, considered to be fibroblasts, were filled with cytoplasmic filaments and contained bizarre shaped nuclei. Mast cells, blood vessels and nerve processes were also present.

Adult↗