The use of mercury in dental amalgam restorations has become the subject of political controversy despite its long history of safe clinical use, and alternative materials based on gallium and indium rather than mercury have been developed. The biological safety of these metals must be evaluated, as part of their assessment as mercury substitutes. The cytotoxicities of mercury (II) nitrate, gallium (III) nitrate, and indium (III) nitrate were assessed at concentrations between 0.001 mmol/L and 1.0 mmol/L, using L929 mouse fibroblasts and the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) colorimetric assay and scanning electron microscopy. The mitochondrial dehydrogenase activity at each metal ion concentration as a percentage of the control was calculated from the absorbance values. The 50% inhibition concentration of mercury (II) nitrate was 0.35 mmol/L for cells in the rapid-growth phase and at confluence; gallium (III) nitrate and indium (III) nitrate did not significantly inhibit dehydrogenase activity in either the growing or confluent phase. Gallium and indium ions were not significantly toxic under the conditions of this assay.
A monoclonal antibody against a pepsin-soluble mammalian type I collagen has been produced. This antibody, subclass IgG1,K-, was specific for type I collagen and did not cross-react with a range of other collagen types or connective tissue proteins. The epitope recognized by the antibody was dependent upon an intact triple-helical structure for the collagen, and was shown by rotary shadowing and by immunoblotting of collagenase-derived fragments to be near the C-terminal of the pepsin-soluble collagen. Although the antibody had a low affinity, with Kd = 4 x M, it could be used for immunohistology of tissue sections and for studies of collagen produced by cells in culture. The antibody, which was raised against human collagen, also recognized type I collagens from certain other species, including calf, pig, sheep, goat and dog.Although a variety of monoclonal antibodies to the genetically distinct collagen types have now been described [l, 21, no antibody has been reported against a processed, mammalian type I collagen [I, 21. For many of the antibodies to other collagen types, chicken collagens have been used as the immunogens; thus the collagens were from a species which was taxonomically distant from the mouse, which would enhance the possibility of obtaining monoclonal antibodies. For type I collagen, which is an especially poor immunogen [l], a monoclonal antibody against neutral-salt-soluble chicken collagen has been reported [3]. The epitope recognized by the antibody, although not specifically identified, was shown to be present in collagen from which the telopeptides had been removed enzymatically, and was dependent on the native, triple-helical conformation of the collagen [3]. This has been the only monoclonal antibody reported against the processed form of native type I collagen, and it does not show reactivity to mammalian type I collagens. For mammalian type I collagens, monoclonal antibodies have been reported against the C-propeptide domain [4] and the N-propeptidase cleavage site [5] but none have been reported against a processed, mammalian type I collagen. In the present study, we report the production of a monoclonal antibody against pepsin-soluble human type I collagen and describe its properties, its specificity and the location of the antigenic determinant to which the antibody binds. MATERIALS AND METHODS Collagen preparationHuman collagen types I, 111 and V were obtained from Sigma Chemical Co. (St Louis, MO) and types I1 and VI Correspondence to J. A. M.
The mouth is pivotal in the generation of flavor, the pleasure of eating, and the selection of food. Flavor—representing the integration of olfaction (smell) with gustation (physiologic taste) and as influenced by oral somatosenses—is rarely afforded attention in oral research and dental practice. This article considers the interrelationship between oral health and flavor and highlights gaps in current knowledge. Altered oral function associated with operative and restorative treatment can feasibly alter the perception of flavor through diverse ways. Oral diseases and the generation of biofilms on restorative materials have potential to influence the oral microbiota and the perception of flavor. Alterations in masticatory function (through tooth loss, restorative materials, and prostheses with nonbiological surfaces and shapes) compounded by associated influences in the composition and quantity of saliva can affect the release of odorants and tastants from foods and beverages. Furthermore, changes occur in the perception of flavor throughout life and are significant in the aging and medically compromised population with the potential to affect nutrition and pleasure. Dental research and clinical practice should be at the forefront of biomedical science in understanding and promoting the importance and relevance of flavor in the well-being of patients. However, more research is required to guide clinical practice in consideration of olfactory and gustatory function as a component of total patient care. Knowledge Transfer Statement: This commentary highlights the research gaps in knowledge pertaining to the association between oral health and flavor and the significance of flavor to dental practice.
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