Oral epithelium

There has also been a report regarding the active transport of antibacterial agents in oral mucosa. In a cell line derived from oral epithelium, the uptake of ciprofloxacin and minocycline was not only saturable and inhibited in the presence of other compounds, but the intracellular levels of both antibiotics were 8 10-fold higher than the extracellular levels as well, demonstrating an active transport process [18]. Whether the permeability of these compounds across the entire oral mucosa occurs via an active transport process, however, remains to be determined. 

Chen SY, Squier CA (1984) The ultrastructure of the oral epithelium. In Meyer J, Squier CA, Gerson SJ (eds.) The Structure and Function of Oral Mucosa. Pergamon Press, Oxford, pp 7-30... 

Collins P, Laffoon J, Squier CA (1981) Comparative study of porcine oral epithelium. J Dent Res 60 543... 

Squier CA (1973) The permeability of keratinized and nonkeratinized oral epithelium to horseradish peroxidase. J Ultrastruct Res 43 160-177... 

Squier CA (1977) Membrane coating granules in nonkeratinizing oral epithelium. J Ultrastruct Res 60 212-220... 

Squier CA (1982) Zinc iodide-osmium staining of membrane-coating granules in keratinized and non-keratinized mammalian oral epithelium. Arch Oral Biol 27 377-382... 

Squier CA, Wertz PW, Cox P (1991b) Thin-layer chromatographic analyses of hpids in different layers of porcine epidermis and oral epithelium. Arch Oral Biol 36 647-653... 

Wertz PW, Squier CA (1991) Cellular and molecular basis of barrier function in oral epithelium. Crit Rev Ther Drug Carrier Syst 8 237-269... 

UIH, Unseheduled DNA synthesis, human oral epithelium and fibroblasts + NT 11 Ide etal. (1982)... 

Hasseus B, Dahlgren U, Bergenholtz G, Jontell M Antigen presenting capacity of Langerhans cells from rat oral epithelium. J Oral Pathol Med 1995 24 56-60. 

Eriksson K, Ahlfors E, George-Chandy A, Kaiserlian D, Czerkinsky C Antigen presentation in the murine oral epithelium. Immunology 1996 88 147-152. 

Replacement of CTAB on the gold nanorod surface has also been achieved by in situ dithiocarbamate (DTC) formation introduced for gold surface protection, see Section 4.3.2.254 Using this protection procedure, the nonspecific uptake of nanorods by KB cells (a tumor cell line derived from oral epithelium) could be greatly reduced. Moreover, following the DTC strategy and using diamino-PEG, different functional... 

Sondell, B., Thomell, L.-E., Stigbrand, T., and Egelrud, T., Immunolcoalization of stratum corneum chymotryptic enzyme in human skin and oral epithelium with monoclonal antibodies evidence of a proteinase specifically expressed in keratinizing squamous epithelia, J. Histochem. Cytochem., 42, 459, 1994. 

In common with all epithelial interfaces (see Section 1.3.2), the epithelium of the oral cavity is supported by a basement membrane, which separates the epithelium from the underlying connective tissue layer (the lamina propria) (Figure 7.1). Oral epithelium is broadly similar to stratified squamous epithelia found elsewhere in the body, for example the skin (see Section 8.2.1), in that cells are produced by mitosis in the basal layer of the epithelium and these proliferating cells push existing cells towards the surface. The phases of this dynamic process are represented in four morphological layers ... 

Figure 7.1 Structure of non-keratinized oral epithelium, as found in the sublingual and buccal regions of the oral cavity. (Note keratinized epithelium has a broadly similar structure however, the epithelial cell layers comprise basal layer, prickle cell layer, granular layer and keratinized layer)...

A primary function of the oral epithelium is to provide a safety barrier, to protect the oral cavity against injury. However, this protective role means that the oral epithelium also presents a considerable barrier to systemic drag delivery. 

The thickness of the oral epithelium varies considerably between sites in the oral cavity ... 

A rich blood supply and lymphatic network in the lamina propria serve the oral cavity, thus drag moieties which traverse the oral epithelium are readily absorbed into the systemic circulation. The blood flow in the buccal mucosa is 2.4 mL min 1 cm 2 whereas that to the sublingual mucosa is 0.97 mL min-1 cm 2. 

Drug moieties absorbed via the oral epithelium are delivered directly into the blood, avoiding first-pass metabolism effects of the hver and gut wall. Thus oral mucosal delivery may be particularly attractive for the delivery of enzymatically labile drugs such as therapeutic peptides and proteins. 

Locally irritating or sensitizing drugs must be used with caution in this route. However, as described above, the oral epithelium is relatively robust and this factor is not as limiting as in other highly sensitive mucosal sites, such as the nasal cavity. 

Repeated sampling of intense oral heat stimuli may result in short-term desensitization. However, this effect may depend upon the spatial and temporal parameters of stimulation, since constant stimulation of small areas of the oral epithelium leads to sensation growth, rather than desensltlzatlon. 

Squier, C. and Hopps, R. A study of the permeability barrier in epidermis and oral epithelium using horseradish peroxidase as a tracer in vitro. Br. J. Derm. 95 123-129, 1976. 

Local factors, systemic factors, or a combination of both can cause halitosis. It is estimated that 80%i of all mouth odors are caused by local factors within the oral cavity, and these odors are most often associated with caries, gingivitis, and periodontitis. Oral malodors occur because of the action of various microorganisms on proteinaceous substances, such as, exfoliated oral epithelium, salivary proteins, food debris, and blood.t ]... 

The major function of the oral epithelium is to provide a protective surface layer between the oral environment and the deeper tissues. The oral epithelium has a squamous epithelium of tightly packed cells that form distinct layers by a process of maturation from the deeper layers to the surface. The pattern of maturation differs in different regions of the oral mucosa... 

---