AAE Abstracts of Papers
Vol. 20, No. 4, April 1994
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Evaluation of the Concentrations of ICAM-I in Healthy and Inflamed Human Dental Pulp C. COOTAUCO* and C. RAUSCHENBERGER, Baltimore College of Dental Surgery, University of Maryland, Baltimore, MD.
Inflammation Increases the 125I-EGF Binding to the Periapical Lesions. S.L.WANG, L.M. LIN, C.Y. WU-WANG, S. LAWSON*, and J.E. SKRIBNER (UMDNJ-NJ Dental School, Newark, N.J.).
Proliferation of the epithelial cell rests of Malassez is often present in the inflammatory periapical (PA) lesions. EGF has been shown to be a potent mitogen for epithelial cells and stimulates DNA and protein synthesis. The purpose of this study was to determine the EGF receptor binding in the inflammatory PA lesions. Six inflammatory PA lesions were obtained from periapical surgery. Immediately after removal, each specimen was divided into two parts. One part was fixed in 10% buffered neutral lbrmalin and prepared for histological examination to distinguish the periapical cyst from granuloma. One out of six samples was confirmed to be cyst. The other part was rinsed with cold DMEM and stored in liquid nitrogen until assayed for 125I-EGF binding. Noninflamed gingival tissues were used as controls since it was impossible to obtain sufficient amounts of health), apical tissues for biochemical analysis. The tissues for 123I-EGF binding assay were used ior membrane preparation ~.zd incubated in duplicate with 125I-EGF. Membrane-bound 125I-EGF was separated immediately by centrifugation and counted in a Packard gamma counter. Specific binding was obtained by substracting the radioactivity of nonspecific binding from total binding and expressed as fmol/m~ .protein. The results indicated that the specific binding of 12~I-EGF to inflamed PA lesions with extensive epithelial proliferation (cyst) was much higher than that of the controls (cont) and PA lesions without epithelial proliferation (granuloma) (cyst : cont : granuloma; 91.3 + 3.9 : 26.8+9.1 : 36.9 + 4.45 fmol/mg protein; Means + S.D.). This study was supported by Endodontic Developmental Grant of R & E Foundation of AAE.
Nitric Oxide Synthase Markers in Rat Tooth Following Pulp Exposure. AS LAW*, KR BAUMGARDNER, JM RANDALL, ST MELLER, and GF GEBHART (University of Iowa) Nitric oxide (NO) production by nitric oxide synthase (NOS) may have a role in blood flow regulation, immunocompetent cell function, and changes in neuronal activity. Several NOS subtypes have been identified, including neuronal NOS (nNOS), endothelial NOS (eNOS), and inducible NOS (iNOS). NADPHdiaphorase (NADPH-d) is a nondiscriminating NOS marker. Antibodies have been developed for iNOS and nNOS. This study examined the distribution NOS in uninflamed and inflamed rat pulp by characterizing NADPH-d activity and iNOS and nNOS immunor~activity (iNOS-i and nNOS-i, respectively). Rats were anesthetized and pinpoint pulp exposures were prepared on maxillary right first molars. One or four days following exposure, rats were perfused and maxillary jaw segments were removed, postfixed, placed in 30% sucrose, decalcified, and processed for NADPH-d, iNOS-i or nNOS-i. NADPH-d intensity increased in blood vessels throughout the exposed pulp compared with controls. This was apparent at both 1 and 4 days following exposure. Vessels in exposed pulps were not apparent in sections stained for nNOS-i or iNOS-i, nNOS-i was not apparent in pulpal nerves. These results suggest that 1) a non-nNOS and non-iNOS form of NOS may be involved in blood flow regulation following pulp exposure and 2) nNOS is likely not present in pulpal nerves. Supported by NIH/NIDR 5K16DE00175-09.
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The acute inflammatory response of the dental pulp to insult involves activation of circulating PMNs, transendothelial migration and movement to the site of involvement. The cytokine inducible adhesion molecule ICAM-1, is expressed on the surface of endothelial cells, PMNs, T-cells, B-cells and monoeytes. It has been associated with the antigen specific emigration of inflammatory cells from the vasculature to the involved site. In addition, ICAM-I has been documented to be released in a soluble form from the surface of its activated cells. The inflamed pulp contains a variety of these immune type cells in increased quantities. Accordingly, the inflamed pulp should contain increased concentrations of ICAM-I but it has yet to be demonstrated in the dental pulp. The purpose of this study was to utilize homogenized pulpal tissue and ELISA techniques to document the presence of ICAM-I in healthy and inflamed dental pulp. Healthy pulpal tissues were obtained from 7 soft tissue impacted third molars and inflamed pulp from I0 carious molars clinically diagnosed with an irreversible pulpitis. Histologic analysis was used to confirm the clinical diagnosis of each sample. A Student's t-test for ICAM-1 concentrations indicated significant differences between healthy and inflamed pulpal samples (p<0.05). These results suggest that ICAM-I may prove to be a suitable clinical marker for evaluating pul0al inflammatory disease. Thus, analysis of ICAM-I is important for the understanding of cytokine inducible, inflammatory cell adhesive interactions during pulp disease and its soluble form could potentially be used as a marker for early pulpal inflammation.
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NOS and CGRP Immunoreactivity Following Sympathectomy and Pulp Exposure. JM RANDALL*, AS LAW, KR BAUMGARDNER, GF GEBHART and ST MELLER (Univ. of Iowa) Nitric oxide (NO), produced by NO synthase (NOS), is involved in neuronal function. Vascular and neuronal changes are associated with pulp inflammation. Sympathetic innervation may regulate vascular changes. This study characterized distribution of NOS, NADPHdiaphorase (NADPH-d, a nondiscriminating NOS marker) and calcitonin gene-related peptide (CGRP) in normal and inflamed pulps of sympathectomized rats. 24 rats were anesthetized and divided into four groups: (1)bilateral superior cervical ganglionectomy (SCGx); (2) right SCGx; (3) left SGCx, or (4) no SCGx. Eight days following SCGx, pinpoint pulp exposures were prepared on the max. right first molar in all groups. Four days following pulp exposure, rats were perfused, jaws removed, postfixed, placed in sucrose, decalcified, and processed for nNOS and CGRP immunoreactivity (NOS-i and CGRPi) and NADPH-d activity. Results: CGRP-i nerve fibers increased adjacent to exposures compared to tissue further from inflammation and to controls. In addition, NADPH-d intensity increased in vessels adjacent to inflammation and throughout inflamed pulps compared with non-inflamed pulps, nNOS-i was not apparent in vessels or nerves of inflamed and non-inflamed pulps. CGRP-i or NADPH-d distribution was similar in non-SCGx and SGCx pulps. Results suggest that 1) CGRP, but not nNOS, is present in nerve fibers in pulp and is unaffected by SCGx, 2) NOS (not nNOS) is present in pulp vessels and is increased by inflammation, but is not affected by SCGx. Supported by Dental Research Award Program and DSA 5K16DE00175-09.