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Biomedical subjects

D C Quick

Publications and source records attributed to D C Quick.

26 records · Page 2Linked to original sources
PubMed1977

Ferric ion, ferrocyanide, and inorganic phosphate as cytochemical reactants at peripheral nodes of Ranvier.

Ferric ion (Fe3+) and ferrocyanide (Fe(CN)64-) were used under a variety of conditions to stain nodes of Ranvier in mammalian peripheral nerves. Principal findings are: 1. Ferric ion will bind to the extracellular nodal gap substance if nerves are pretreated with a phosphate buffer; or, it will bind to the cytoplasmic surface of the nodal axolemma if pretreatment is with cacodylate or veronal--acetate buffer. 2. Ferrocyanide will bind to the inner surface of the nodal axolemma, where it may react with ferric ion to form a blue stain, or with an osmium compound to form a black stain. 3. Ferric ion and ferrocyanide are bound to nodes as colloidal precipitates, and may migrate away from their sites of formation. 4. Not all nodes in a single piece of tissue, or in a single fibre have identical staining properties. It is concluded that ferric ion, ferrocyanide, and inorganic phosphate are valuable as cytochemical reactants for peripheral nodes of Ranvier, but they must be used in carefully controlled experimental situations in order to avoid spurious results.

Animals↗
PubMed1977

Evidence for inorganic phosphate binding at nodes of Ranvier in peripheral nerves.

Ferric ion is bound to different sites at nodes of Ranvier, depending on how the nerves are prepared. By immersing fresh, unfixed nerves in phosphate buffer, cacodylate buffer, or physiological saline prior to staining with ferric ion and ferrocyanide, it can be shown that binding of ferric ion to the extracellular nodal gap substance requires pretreatment with inorganic phosphate. This implies that phosphate anions are bound to the gap substance where they may then promote precipitation of ferric ion. These results call for a re-evaluation of data that depend on ferric ion binding to nodes of Ranvier. They also open the possibility that affinity for anions in general, or phosphate in particular, may be a significant feature of extracellular molecules present at nodes.

Animals↗
PubMed1977

Cytochemical differentiation of the axon membrane in A- and C-fibres.

Guinea pig and rat sciatic nerves were fixed with cacodylate-buffered aldehydes and OsO4, and were stained with ferric ion and ferrocyanide. Cytoplasmic surfaces of the non-myelinated nodal axon membrane of A-fibres display distinct electron-dense aggregates of stain. These aggregates were not observed in association with the paranodal or internodal axolemma. The membranes of C-fibres exhibit no staining under these conditions. Thus, the nodal axolemma of normal myelinated fibres is structurally distinct from both the myelinated internodal membrane, and from the axolemma of C-fibres. The ferric ion-ferrocyanide technique may provide a method for marking axonal membrane with normal nodal properties.

Animals↗
PubMedDate not supplied

Specific staining of the axon membrane at nodes of Ranvier with ferric ion and ferrocyanide.

Ferric ion and ferrocyanide were used as stains for light and electron microscopy of peripheral nerves. In rat sciatic nerves, it was found that ferric ion preferntially binds to the cytoplasmic surface of the axon membrane at nodes of Ranvier but not at internodal regions. In myelinated axons in the electric organ of the gymnotid fish, Sternarchus albifrons, the small excitable nodes are similarly stained, but the larger inexcitable nodes are not stained by ferric ion. Staining of the inner surface of the nodal membrane appears to be related to a structural specialization of this membrane, rather than accessibility to stain. Our data thus show a chemical differentiation of the inner surface of the axon membrane between nodes and internodes in normal peripheral nerve fibers and between the inner surface of the axon membrane at active nodes, and the internodes in the Sternarchus electrocyte axons.

Animals↗
PubMedDate not supplied

Lunate and perilunate dislocations in professional football players. A five-year retrospective analysis.

The purpose of this retrospective study was to review the treatment and prognosis of lunate and perilunate carpal dislocations in professional football players in the National Football League over a 5-year period. There were 7 lunate and 3 perilunate dislocations in 10 players. The mechanism of injury was hyperextension in 9 of 10 players. Five players were subsequently treated by closed reduction and percutaneous pinning; the others were treated by open reduction and K-wire fixation. No player was treated by cast immobilization alone. Intraoperative techniques, postoperative immobilization and protection, return to play, final follow-up physical examination, radiographic evaluation, and complications were reviewed. Results of this study clearly demonstrate that lunate and perilunate carpal dislocations do not mean the end of a career in professional football, although a minimum of 4 weeks of playing time is lost. Treatments varied with respect to open or closed reductions, placement of pins, casts, and time of immobilization. None of the variations was clearly superior or detrimental, although four of the five players who returned to play in the same season were treated by closed reduction with percutaneous pinning.

Carpal Bones↗
PubMedDate not supplied

Lumbar transverse process fractures in professional football players.

In the general population, fractures of the transverse processes of lumbar vertebrae occur in cases of high-energy blunt trauma, often in motor vehicle accidents. Football players may incur the same fractures, but the circumstances and outcomes are different in this specific subgroup. A review of 29 cases among National Football League players reveals that associated visceral injuries are rare, and the time lost from sports is only an average of 3.5 weeks.

Football↗
PubMedDate not supplied

Use of a scanning laser three-dimensional digitizer for analysis of dental materials.

A scanning laser 3-D digitizer was used to measure dimensions in dental impression materials, and its performance was compared with that of micrometer-based measuring instruments. It was found that the digitizer was precise enough to detect dimensional changes on the order of 40 microns, and it was automated enough to be convenient and almost eliminate operator errors. However, its operation required the services of an engineer for maintenance and a programmer for data analysis.

Algorithms↗