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Biomedical subjects

R V McKinney

Publications and source records attributed to R V McKinney.

At least 37 records · Page 2Linked to original sources
PubMed1985

Recovery of rat gastric mucosa following single fluoride dosing.

Rats' stomachs were intubated with 0.1 N HCl or 100 mM NaF in 0.1 N HCl and excised after 1, 12, 24, 48 h or 7 days for light microscopy. The NaF solution caused erosive injury to the oxyntic glandular mucosa 1 h after application. Progressive stages of recovery were seen at 12, 24 and 48 h after fluoride dosing. Complete recovery was seen 7 days after exposure to fluoride. The kinetics of the recovery process from fluoride injury appear to be similar to those which have been reported for gastric injury produced by other substances.

Animals↗
PubMed1985

Evidence for a junctional epithelial attachment to ceramic dental implants. A transmission electron microscopic study.

The interface of the crevicular gingiva with the surface of a dental implant is a critical zone representing the potential biological seal which protects the underlying bone and soft tissue-supporting mechanisms from destructive extraneous substances. Ultrastructural examination of regenerated junctional epithelial cells interfacing surgically placed endosteal dental implants, comprised of alpha-alumina oxide ceramic in single crystalline form, exhibited an external basal lamina and linear body located between the external surface epithelial cell and the implant. In addition, hemidesmosomes were located at intervals along the outer junctional epithelial plasma membrane. The component substructures of the basal lamina and the hemidesmosomes were similar to those seen interfacing natural teeth. The linear body was an electron-dense structure between the lamina densa and the inert biomaterial. This study provides ultrastructural evidence for the presence of an attachment complex between gingiva and aluminum oxide implants which is analogous to that seen around natural teeth. These data support concept that a viable biological seal can develop around endosteal dental implants and provide support for satisfactory clinical service.

Animals↗
PubMed1984

Surface changes in rat gastric mucosa induced by sodium fluoride: a scanning electron microscopic study.

This paper describes the ultrastructural, topographical changes seen in rat gastric mucosa following application of 0.1 N HCl or 1, 10 or 50 mM NaF in 0.1 N HCl to the stomach. No morphological differences were noticed between the 0.1 N HCl (control) and 1 mM NaF in 0.1 N HCl specimens. Ten milliomolar NaF in 0.1 N HCl produced some desquamation of surface mucous epithelial cells while 50 mM NaF produced extensive damage to cells surrounding the gastric gland openings (foveolae) as well as interfoveolar cell loss.

Animals↗
PubMed1984

The effects of fluoride on the gastric mucosa of the rat.

Fluoride is widely used for the prevention of dental caries. Very low concentrations of fluoride are routinely ingested in optimally fluoridated drinking water of many communities. Higher concentrations of fluoride in toothpastes, mouthrinses and topically applied gels also may be ingested, especially by children. The potential effect of ingested fluoride on the gastric mucosa was the subject of this investigation. Solutions of 0, 1, or 10 mM NaF in 0.1 N HCl were placed in rat stomachs in vivo for up to one hour. The effects of fluoride on the structure and function of the gastric mucosa were determined. Histologic and SEM examinations revealed dose- and time-dependent damage to the surface mucous cells. The 10 mM, but not the 1 mM, NaF solution increased gastric mucosal permeability to small but not to large molecules.

Animals↗
PubMed1984

Scanning electron microscopy of plasma etched implant specimens.

Following surface etching of previously processed plastic embedded specimens containing hard and soft tissues and implanted biomaterials with oxygen plasma, the fine structure of the tissues can be examined by scanning electron microscopy. One micrometer plastic orientation sections (with the implant removed in processing) and 110 microns histological sections (with the implant in situ) were examined. Direct comparison can be made between the scanning and histological observations. An examination in situ of oral tissues next to the biomaterial was also made, care being taken to minimize damage to the specimen. The fine structure of intracellular organelles was examined in detail. The method allows consecutive gathering of histological and ultrastructural data from the same plastic embedded specimen.

Animals↗
PubMed1984

The biomaterial-tissue interface: a morphological study utilizing conventional and alternative ultrastructural modalities.

The interface between oral tissues and ceramic endosteal dental implants was investigated in 36 experimental cases in dog jaws. Conventional electron microscopic modalities showed those tissues adjacent to the implants to be viable with no adverse cellular response to the biomaterial. A procedure to retrieve additional ultrastructural data from previously processed biological material was developed to expand upon these data. This included surface-etching with oxygen plasma of routinely processed electron microscopy specimens and formalin fixed histological specimens for scanning electron microscopy (SEM) study; and, cryofracturing of similar histological specimens for additional transmission electron microscopic (TEM) analysis. Results from these alternative protocols supported our observations from conventional studies of the direct association of bone and epithelia to the implant. In addition, they demonstrated a unique portrayal of the epithelial maturation patterns. Further, this alternative TEM method showed excellent retention of cellular integrity and demonstrated a hemidesmosomal-external basal lamina attachment apparatus at the junctional epithelial-implant interface. This latter composite attachment structure was not retained in our previous conventional microdissection procedures. Thus, the interface between oral tissues and the single crystal sapphire endosteal dental implant could be elucidated by these protocols.

Animals↗
PubMed1983

A statistical analysis of the clinical response to the single-crystal sapphire endosseous dental implant in dog jaws.

A statistical analysis was carried out on the clinical evaluatory data gathered from a two-year longitudinal study of the single-crystal sapphire endosteal dental implant in dog jaws. Statistically, the implants behaved either better than control molars (clinically), or in a manner similar to control molars. These data suggest an excellent prognosis for the single-crystal sapphire dental implant.

Aluminum Oxide↗