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Abstract #8 — Regulation of the release of CGRP-like immunoreactivity from bovine dental pulp
Vol. 18, No. 4, April 1992
AAE Abstracts of Papers (Abstract #8, continued)
ABSTRACT #6 - Use of a gallium alloy as a retrofilling material. R.A. Barkhordar, A. Kupelion*, W.S. Eakle, L.G. Watanabe University of California, San Francisco, California Many materials have been used as retrofillings. This study sought to evaluate a gallium alloy as a substitute for mercury containing amalgam for use as a retrofilling material. Eighty human maxillary anterior teeth were cleansed and shaped, and the teeth were assigned to eight groups of ten each. The root canals were obturated with guttapercha and Roth's sealer, and the apical 2mm of each root was resected. In all groups a retrofilling preparation was made to a depth of a 331 bur. The apical preparations were filled in the following manner: Gr I, amalgam (A) only; Gr II, gallium alloy (G) only; Gr III, Panavia + A;Gr IV, Panavia + G;Gr V, Amalgabond + A; Gr VI, Amalgabond + G; Gr VII, polyacrylic acid + A; Gr VIII, polyacrylic acid + G. All the root surfaces with the exceptionof 2ram from the resected line were coated with clear varnish. Teeth were immersed in methylene blue for 24 hours. After vertical sectioning, dye penetration was measured under dissecting microscope. The means of the apical leakage (mm) were: 1=3.0+1.4; 11=1.2+0.2;111=1.4+0.3;IV=0.5 +0.2; V=1.6+0.6; VI=0.0+0.2; VII= 1.2+0.4;VIII = 0.2+0.3. ANOVA and SNK tests showed differences between the gallium alloy groups and the amalgam groups, as well as some differences among these groups (P<.05). This study suggest that gallium alloys may have potential as retrofilling materials based on sealing ability.
Research Seminar II Thursday, May 7, 2:00-5:00 pm Graduate Student Section ABSTRACT # 7 - Retention of the hypoxic cell marker, misonidazole, in dental pulp. K.R. Baumgardner*, R.E. Walton, J.W. Osborne, J.L Born University of Iowa, Iowa City, Iowa University of New Mexico, Albuquerque, New Mexico Misonidazole (MISO) is a bioreductively activated marker of cellular hypoxia which preferentially binds to cells with decreased oxygen tension. Pulp cells may undergo transient hypoxia during environmental or induced injuries with resultant damagefrom impaired cellular metabolism. The purpose of this study was to characterize the degree of 3H-MISO retention in both normoxic and experimentallyinduced hypoxic rat dental pulp using liquid scintillation counting (LSC) and autoradiography (ARG). Rats were injected intraperitoneally with either 3H-MISO, unlabeled MISO, or saline and then divided into normoxic and hypoxic groups. Normoxic animals were maintained at ambient pressure. Hypoxia was induced by placing animals in a hypobaric chamber at 0.5 atm. for 24 hours. All teeth were removed in block section, decalcified, and prepared using routine histologic, autoradiographic, and LSC techniques. The hypoxic animals did show significantly increased retention of 3H-MISO. Specifically, there was a three fold increase using LSC, and a significant increase in labeling per unit areas using ARG. The labeling pattern was uniform throughoutthe pulp. In conclusion, the experimentally-induced hypoxia facilitated increased 3H-MISO binding to the dental pulp that was detectable using liquid scintillation counting and autoradiography. Supported by NIH/NIDR Grant #KI6-DE00175. ABSTRACT #8 - Regulation of the release of CGRP-like immunoreactivity from bovine dental pulp. K.M. Hargreaves*, W.R. Bowles University of Minnesota, Minneapolis, Minnesota Although neuropeptides such as calcitonin gene-related peptide (CGRP) are believed to regulate inflammation such as pulpitis comparatively little is known about the regulation of neuropeptide secretion from dental pulp. This is an important topic since drugs that alter neuropeptide release may have clinical efficacy as anti189
inflammatory/analgesic agents. Our study evaluated vitro in superfusion of dental pulp as an appropriate method for determining the pharmacologic regulation of neuropeptide secretion. Bovine pulp tissue was superfused with oxygenated Kreb's buffer and exposed to high potassium (50mM) Kreb's buffer. Superfusion was also done in the absence of calcium, with the addition of lidocaine (10mM), or with capsaicin (1-60uM) to determine their effects on the release of iCGRP from bovine dental pulp. Perfusate samples were frozen, lyophylized, and radioimmunoassays were performed. Substance P (SP) and CGRP peptide standards were assayed under the same conditions as the superfusate samples. Parallel dilution curves were also performed. Tissue levels of iCGRP were more than 17-fold greater than corresponding iSP levels when evaluatedfrom aliquots taken from the same teeth. Superfusate levels of iCGRP increased 3- to 5-fold after exposure to high potassium buffer (p<0.01). Potassium-evoked release of iCGRP was completely dependent on the presence of calcium (p<0.001). Lidocaine suppressed the basal release and abolishedthe potassium-evoked release of iCGRP (p<0.01 for both). Capsaicin produced a dose-related increase in the peak release of iCGRP with a 2.7uM concentration of capsaicin having equivalent effects as compared to 50mM potassium. Collectively, these studies indicate the in vitro superfusion of dental pulp is a suitable method for developing and evaluating drugs which alter peripheral secretion of neuropeptides.
ABSTRACT #9 - The effect of drying time of periodontal ligament cell vitality. E.K. Garnson*, T.C. Dumsha, R. Sydiskis University of Maryland, Baltimore, Maryland The preservation of the periodontal ligament cells on avulsed teeth is critical in achieving successful long term healing of replanted teeth. This study investigated the effect of drying time on periodontal ligament cell vitality prior to the placement of the teeth into milk as a storage media. A dual labeling fluorogenic labeling technique was utilized in order to discriminate between viable and non-viable cells. Fifty-five freshly extracted human teeth were divided into seven groups with dry storage times from 0-120 minutes. Following the dry storage, the teeth were stored for 45 minutes in milk. The PDL cells were retrieved from the root surfaces using a step-wise trypsinization procedu re. The PDL cells were then stained with fluorodiacetate (FDA) and propidium iodine (PI). After 20 minutes of dry storage, there was a statistically significant decrease in the number of viable PDL cells when compared to 0 and 10 minute dry times. At 30 minutes of dry storage, there was a statistically significant decrease in the number of viable PDL cells when compared to 10 and 20 minutes of dry time. After 45 minutes and 120 minutes of dry tim e, few viable cells remained. Milk is a suitable storage media for maintaining PDL cell vitality. The FDA/PI labeling technique is an effective method for comparing the number of viable and non-viable PDL cells. This research was supported by the Research and Education Foundation of the American Association of Endodontists. ABSTRACT #10 - Concentration of interleukin I-B in symptomatic and asymptomatic human periradicular lesions. G. Lira*, M. Torabinejad, J. Kettering, T. Unkhart, R. Finkleman Loma Linda University, Loma Linda, California Interleukin (IL) I-B has been shown to be a potent mediator of bone resorption. The purpose of this study was to determine the concentration of IL-IB in the sera and tissue samples of periradicular lesions. Serum samples (23) and periapical tissue specimens from symptomatic (12) and asymptomatic (10) patients were obtained and frozen immediately in liquid nitrogen and stored at minus 70oC. Pulpal tissues (10) from unerupted or intact third molars as well as chronically inflamed gingival tissues (5) were also obtained, frozen and used as negative and positive controls respectively. Samples were homogenized and centrifuged, and the supernatants were tested for concentration of IL-IB by the Elisa method and normalized to total
AAE Abstracts of Papers (Abstract #8, continued)
ABSTRACT #6 - Use of a gallium alloy as a retrofilling material. R.A. Barkhordar, A. Kupelion*, W.S. Eakle, L.G. Watanabe University of California, San Francisco, California Many materials have been used as retrofillings. This study sought to evaluate a gallium alloy as a substitute for mercury containing amalgam for use as a retrofilling material. Eighty human maxillary anterior teeth were cleansed and shaped, and the teeth were assigned to eight groups of ten each. The root canals were obturated with guttapercha and Roth's sealer, and the apical 2mm of each root was resected. In all groups a retrofilling preparation was made to a depth of a 331 bur. The apical preparations were filled in the following manner: Gr I, amalgam (A) only; Gr II, gallium alloy (G) only; Gr III, Panavia + A;Gr IV, Panavia + G;Gr V, Amalgabond + A; Gr VI, Amalgabond + G; Gr VII, polyacrylic acid + A; Gr VIII, polyacrylic acid + G. All the root surfaces with the exceptionof 2ram from the resected line were coated with clear varnish. Teeth were immersed in methylene blue for 24 hours. After vertical sectioning, dye penetration was measured under dissecting microscope. The means of the apical leakage (mm) were: 1=3.0+1.4; 11=1.2+0.2;111=1.4+0.3;IV=0.5 +0.2; V=1.6+0.6; VI=0.0+0.2; VII= 1.2+0.4;VIII = 0.2+0.3. ANOVA and SNK tests showed differences between the gallium alloy groups and the amalgam groups, as well as some differences among these groups (P<.05). This study suggest that gallium alloys may have potential as retrofilling materials based on sealing ability.
Research Seminar II Thursday, May 7, 2:00-5:00 pm Graduate Student Section ABSTRACT # 7 - Retention of the hypoxic cell marker, misonidazole, in dental pulp. K.R. Baumgardner*, R.E. Walton, J.W. Osborne, J.L Born University of Iowa, Iowa City, Iowa University of New Mexico, Albuquerque, New Mexico Misonidazole (MISO) is a bioreductively activated marker of cellular hypoxia which preferentially binds to cells with decreased oxygen tension. Pulp cells may undergo transient hypoxia during environmental or induced injuries with resultant damagefrom impaired cellular metabolism. The purpose of this study was to characterize the degree of 3H-MISO retention in both normoxic and experimentallyinduced hypoxic rat dental pulp using liquid scintillation counting (LSC) and autoradiography (ARG). Rats were injected intraperitoneally with either 3H-MISO, unlabeled MISO, or saline and then divided into normoxic and hypoxic groups. Normoxic animals were maintained at ambient pressure. Hypoxia was induced by placing animals in a hypobaric chamber at 0.5 atm. for 24 hours. All teeth were removed in block section, decalcified, and prepared using routine histologic, autoradiographic, and LSC techniques. The hypoxic animals did show significantly increased retention of 3H-MISO. Specifically, there was a three fold increase using LSC, and a significant increase in labeling per unit areas using ARG. The labeling pattern was uniform throughoutthe pulp. In conclusion, the experimentally-induced hypoxia facilitated increased 3H-MISO binding to the dental pulp that was detectable using liquid scintillation counting and autoradiography. Supported by NIH/NIDR Grant #KI6-DE00175. ABSTRACT #8 - Regulation of the release of CGRP-like immunoreactivity from bovine dental pulp. K.M. Hargreaves*, W.R. Bowles University of Minnesota, Minneapolis, Minnesota Although neuropeptides such as calcitonin gene-related peptide (CGRP) are believed to regulate inflammation such as pulpitis comparatively little is known about the regulation of neuropeptide secretion from dental pulp. This is an important topic since drugs that alter neuropeptide release may have clinical efficacy as anti189
inflammatory/analgesic agents. Our study evaluated vitro in superfusion of dental pulp as an appropriate method for determining the pharmacologic regulation of neuropeptide secretion. Bovine pulp tissue was superfused with oxygenated Kreb's buffer and exposed to high potassium (50mM) Kreb's buffer. Superfusion was also done in the absence of calcium, with the addition of lidocaine (10mM), or with capsaicin (1-60uM) to determine their effects on the release of iCGRP from bovine dental pulp. Perfusate samples were frozen, lyophylized, and radioimmunoassays were performed. Substance P (SP) and CGRP peptide standards were assayed under the same conditions as the superfusate samples. Parallel dilution curves were also performed. Tissue levels of iCGRP were more than 17-fold greater than corresponding iSP levels when evaluatedfrom aliquots taken from the same teeth. Superfusate levels of iCGRP increased 3- to 5-fold after exposure to high potassium buffer (p<0.01). Potassium-evoked release of iCGRP was completely dependent on the presence of calcium (p<0.001). Lidocaine suppressed the basal release and abolishedthe potassium-evoked release of iCGRP (p<0.01 for both). Capsaicin produced a dose-related increase in the peak release of iCGRP with a 2.7uM concentration of capsaicin having equivalent effects as compared to 50mM potassium. Collectively, these studies indicate the in vitro superfusion of dental pulp is a suitable method for developing and evaluating drugs which alter peripheral secretion of neuropeptides.
ABSTRACT #9 - The effect of drying time of periodontal ligament cell vitality. E.K. Garnson*, T.C. Dumsha, R. Sydiskis University of Maryland, Baltimore, Maryland The preservation of the periodontal ligament cells on avulsed teeth is critical in achieving successful long term healing of replanted teeth. This study investigated the effect of drying time on periodontal ligament cell vitality prior to the placement of the teeth into milk as a storage media. A dual labeling fluorogenic labeling technique was utilized in order to discriminate between viable and non-viable cells. Fifty-five freshly extracted human teeth were divided into seven groups with dry storage times from 0-120 minutes. Following the dry storage, the teeth were stored for 45 minutes in milk. The PDL cells were retrieved from the root surfaces using a step-wise trypsinization procedu re. The PDL cells were then stained with fluorodiacetate (FDA) and propidium iodine (PI). After 20 minutes of dry storage, there was a statistically significant decrease in the number of viable PDL cells when compared to 0 and 10 minute dry times. At 30 minutes of dry storage, there was a statistically significant decrease in the number of viable PDL cells when compared to 10 and 20 minutes of dry time. After 45 minutes and 120 minutes of dry tim e, few viable cells remained. Milk is a suitable storage media for maintaining PDL cell vitality. The FDA/PI labeling technique is an effective method for comparing the number of viable and non-viable PDL cells. This research was supported by the Research and Education Foundation of the American Association of Endodontists. ABSTRACT #10 - Concentration of interleukin I-B in symptomatic and asymptomatic human periradicular lesions. G. Lira*, M. Torabinejad, J. Kettering, T. Unkhart, R. Finkleman Loma Linda University, Loma Linda, California Interleukin (IL) I-B has been shown to be a potent mediator of bone resorption. The purpose of this study was to determine the concentration of IL-IB in the sera and tissue samples of periradicular lesions. Serum samples (23) and periapical tissue specimens from symptomatic (12) and asymptomatic (10) patients were obtained and frozen immediately in liquid nitrogen and stored at minus 70oC. Pulpal tissues (10) from unerupted or intact third molars as well as chronically inflamed gingival tissues (5) were also obtained, frozen and used as negative and positive controls respectively. Samples were homogenized and centrifuged, and the supernatants were tested for concentration of IL-IB by the Elisa method and normalized to total