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Biomedical subjects

G A Gill

Publications and source records attributed to G A Gill.

5 recordsLinked to original sources
PubMed2005

Characterisation of adherens and tight junctional molecules in normal animal larynx; determining a suitable model for studying molecular abnormalities in human laryngopharyngeal reflux.

BACKGROUND: The disruption of intercellular junctions in the larynx is a pathological feature of laryngopharyngeal reflux (LPR). Good experimental models are necessary to gain greater insight into the molecular mechanisms and alterations that result from abnormal exposure of the laryngeal epithelium to acid refluxate. AIMS: To characterise laryngeal tissues from different species to determine the most suitable for use in experimental studies of LPR. METHODS: Human and non-human laryngeal tissues (mouse, rat, guinea pig, porcine, and rabbit) were studied. Histological characterisation was performed by light microscopy. The expression and subcellular localisation of adherens junctional molecules (E-cadherin and beta catenin) was evaluated by immunohistochemistry, and tight junction molecules (occludin and zonula occludens 1 (ZO-1)) by western blotting. The ultrastructural features of porcine and human tissue were assessed by electron microscopy. RESULTS: Porcine tissue revealed both respiratory-type and stratified squamous epithelium, as seen in the human larynx. The expression and subcellular localisation of the E-cadherin-catenin complex was detected in all species except mouse and rat. The pattern of ZO-1 and occludin expression was preserved in all species. CONCLUSION: The expression of intercellular junctional complexes in porcine epithelium is similar to that seen in humans. These results confirm the suitability of these species to study molecular mechanisms of LPR in an experimental system.

Adherens Junctions↗
PubMed2001

Processes influencing rainfall deposition of mercury in Florida.

The primary goal of the Florida Atmospheric Mercury Study (FAMS) was to quantify the atmospheric deposition of Hg throughout Florida. Monthly integrated precipitation and weekly integrated particulate samples were collected at 10 sites in Florida for periods ranging from 2 to 5 yr. The monthly rainfall across the state and the concentrations of Hg in wet-only and bulk deposition increased by a factor of 2-3 during the summertime "wet season" (May-October). These parallel increases in rainfall amount and Hg concentration resulted in 5-8-fold increases in rainfall Hg deposition during the wet season. The annual volume-weighted Hg concentrations ranged from 14 +/- 2 to 16 +/- 2 ng/L across southern Florida, and the annual rainfall Hg fluxes ranged from 20 +/- 3 to 23 +/- 3 micrograms m-2 yr-1. The weekly integrated particulate Hg concentrations in southern Florida were low (4.9-9.3 pg/m3) and did not exhibit strong seasonal variability. Considering the pronounced seasonal pattern in rainfall Hg deposition, the relatively uniform summertime rainfall Hg concentrations, and the low concentrations of particulate Hg, we conclude that processes other than particulate Hg transport and scavenging govern rainfall Hg deposition in southern Florida. We hypothesize that long-range transport of reactive gaseous Hg (RGM) species coupled with strong convective thunderstorm activity during the summertime represents > 50% of the Hg deposition in southern Florida. Model calculations indicate that local anthropogenic particulate Hg and RGM emissions account for 30-46% of the summertime rainfall Hg deposition across the southern Florida peninsula.

Air Pollutants↗
PubMed1989

[Soldering without transition (osteoassimilation) between the human maxillary bone and a compact dental implant in natural calcite from marine invertebrate].

We present evidence for the formation of woven bone between human maxillary lamellar bone (the target site) and a coral implant (Corallium johnsoni Gray). This newly formed bone is characterized by numerous osteocytes located in spherical lacunae and having many ramified processes directed towards the coral; some of these processes continue into the implant surface. Healthy osteocytes were detected within the superficial part of the coral, next to the newly formed bone. Neither osteoclast nor surface of resorption has been noticed. All these observations indicate tight welding or osteoassimilation without any transition between the maxillary bone and the graft. We have obtained analogous results by using grafts of molluscan mother-of-pearl. Our results differ from those reported by other authors, probably due to the compactness of the biomaterial used here.

Animals↗
PubMed1988

[Substitution of the dental root by aquatic invertebrate skeletons in animals and man].

The biocompatibility of mammal bone with aragonite and calcite skeletons of aquatic invertebrates (Corals, Molluscs) led us, after animal experimentation, to implant in humans artificial dental roots derived from such invertebrates. These roots, incorporated but not resorbed, serve as supports for a prosthetic crown; they are equipped to isolate the root from the buccal cavity and to ensure shock absorbtion during mastication. The greater ease of implanting artificial teeth and their excellent acceptance will in many cases modify the strategy of current dental treatment.

Adult↗