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At least 937 records · Page 52Linked to original sources
PubMed1991

Subcellular distribution of enkephalin precursor proteins in rat dental pulp and the usefulness as a substrate for enkephalin-producing enzymes.

The subcellular distribution of enkephalin (EK) precursor proteins was investigated to clarify the intracellular site of biosynthesis of EK in rat dental pulp tissue. The contents of met-EK-like peptides in nuclear, microsomal, and supernatant fractions of the pulp tissue were markedly increased after sequential digestion with trypsin and carboxypeptidase B, indicating the enrichment of the precursors in these fractions. Sephadex G-100 gel filtration showed a common peak of the precursor proteins in the homogenate and its microsomal and supernatant fractions, and the molecular weight was determined to be about 58,000 by SDS polyacrylamide gel electrophoresis. Both the partially purified precursor protein from the supernatant fraction and N alpha-benzoyl-DL-arginine-beta-naphthylamide (BANA) were used as substrates for a lysosomal enzyme separated by Sephadex G-75 gel filtration. The major peak of EK-producing activity of the enzyme was identical with that of BANA-degrading activity of the enzyme. These results demonstrate the EK-producing activity of lysosomal proteinase, and also indicate the usefulness of the two substances as substrates for the enzyme.

Animals↗
PubMed2006

Regulation of ALP activity by TNF-alpha on human dental pulp.

In this study, we examined the effects of TNF-alpha on Bone morphogenetic protein (BMP-2), Smads (which play intracellular signaling of BMPs) expression and alkaline phosphatase (ALP) activity of human dental pulp (HDP) cells to clarify the mechanism of tertiary dentin formation. The quantity of RT-PCR product for BMP-2 from the HDP cells stimulated by TNF-alpha is increased. However, ALP activity was not increased on the cells incubated with TNF-alpha. On the other hand, ALP activity was significantly increased on HDP cells treated with Ammonium Pyrrolidinedithiocarbamate (PDTC, NF- kappaB inhibitor) groups and combined supplementation of TNF-alpha and PDTC groups. Furthermore, we examined the effect of TNF-alpha and PDTC on Smad7 expression using RT-PCR and western blot analysis. Smad7 expression in HDP cells was increased by TNF-alpha, but decreased by PDTC treatment. These results suggest that NF- kappaB and Smad7 play an important role in the down regulation of ALP activity by TNF-alpha on HDP cells.

Alkaline Phosphatase↗
PubMed1987

Cocaine-sensitive O-methylation of noradrenaline in dental pulp of the rabbit: comparison with the rabbit ear artery.

Incisor pulp from the rabbit metabolises exogenous noradrenaline in concentrations between 0.12 and 1.2 mumol/l mainly to NMN. Effects of chronic sympathetic denervation indicated that in incisor pulp the NMN is extraneuronal in origin, and that DOPEG and DOMA formation, as well as a major part of the noradrenaline which accumulates in the tissue, are associated with the sympathetic nerves. NMN formation was unaffected by hydrocortisone 210 mumol/l, but was strongly inhibited by cocaine 30 mumol/l. These effects contrasted with those in the rabbit ear artery, where NMN formation was increased by cocaine 30 mumol/l and decreased by hydrocortisone 210 mumol/l. In COMT-inhibited denervated pulp, cocaine inhibited the accumulation of noradrenaline. Monoamine fluorescence histochemistry of pulp exposed to noradrenaline 50 mumol/l indicated that cocaine-sensitive uptake occurred in fibroblasts. It is concluded that O-methylation of noradrenaline in dental pulp involves prior uptake of the amine by a process resembling uptake1 but which is distinguished from uptake1 by its extraneuronal location.

Animals↗
PubMed1996

Influence of particle size of calcium phosphate ceramics as a capping agent on the formation of a hard tissue barrier in amputated dental pulp.

The purpose of this research was to compare the effect of two different particle sizes of hydroxyapatite and beta-tricalcium phosphate as capping agents on hard tissue barrier formation after experimental pulpotomy in canine dental pulp. By the thirtieth day after pulp exposure and capping with hydroxyapatite-300 (particle size, 300 microns), a hard tissue barrier was formed in 8 of 17 specimens. A newly formed barrier was seen around the hydroxyapatite particles and connecting neighboring particles. Capping with tricalcium phosphate-300 (particle size, 300 microns) led to the formation of a hard tissue barrier surrounding the particles in 11 of 17 specimens. In contrast, using hydroxyapatite-40 (particle size, 40 microns) and beta-tricalcium phosphate-40 (particle size, 40 microns), hard tissue barrier formation was poor and almost all pulp tissues showed infiltrations of inflammatory cells or abscess formation. These findings suggest that the particle size of hydroxyapatite and beta-tricalcium phosphate is an important factor in reparative hard tissue formation.

Animals↗
PubMed1991

[Fine tissue studies of the nerve supply to the dental pulp in domestic sheep (O. ammon aries Linné, 1758)].

The nerve supply of the pulp was investigated in 17 sheep of various breeds and age groups belonging to both sexes, using light and electron microscopy. The following results were obtained: The dental pulp of sheep is supplied with myelinated and unmyelinated nerve fibres. The subodontoblastic plexus of Raschkow, as found in man, is absent in sheep. Single axons may be found in the predentine between the odontoblasts and near Tomes' processes. The rare occurrence of both subodontoblastic nerve fibres and cells of the immune system in the ovine pulp is discussed in relation to evolutionary processes, in light of the fact that sheep are relatively resistant to caries.

Animals↗
PubMed1989

The effect of newly developed root canal sealers on rat dental pulp cells in primary culture.

Cytotoxicity was compared between new root canal sealers (New A, New B, and New B-2) and conventional root canal sealers (AH26, Diaket, Canals, Tubi-Seal, and Sealapex). Dental pulp cells of rats, obtained through primary cell culture, were used. In the experiments with the freshly prepared sealers, the incorporation of [3H]thymidine into cellular DNA was analyzed. In the experiments with the set sealers, the morphological changes of cells were microscopically examined. In the experiments with the fresh sealers, AH26 and Diaket showed strong inhibitive effects on the DNA synthesis, whereas no such effects were noted with the new sealers and Sealapex. On the other hand, in the experiments with the set sealers, the new sealers and Diaket exerted little influence on the cells. However, other sealers had considerable toxicity. These results suggest that the new sealers were the least toxic in vitro, compared with five conventional sealers.

Animals↗
PubMed1981

Effect of trigeminal tractotomy on behavioral response to dental pulp stimulation in the monkey.

Trigeminal tractotomy near the level of the obex was carried out in 10 macaque monkeys. Behavioral responses were evaluated by a quantitative paradigm measuring lever-press responses to electrical stimulation of the dental pulp or facial skin, and by assessing facial response to cutaneous pin-scratch before and after the tractotomy. Two pharmacological agents, strychnine and L-dopa, were administered and their effect on behavioral responses to these stimuli was studied. Tractotomy did not produce dental analgesia. Thresholds for escape from cutaneous electrical stimulation of facial skin, however, were elevated, consistent with marked hypalgesia to pin-scratch. The adversive responses to pin-scratch were absent in peripheral portions of the face, but near the midline and inside the oral cavity they were usually decreased or normal. Pharmacological agents caused a reduction in escape thresholds to cutaneous electrical stimulation and a shrinkage or abolition of the zone of analgesia to pin-scratch. The results imply that trigeminal nucleus caudalis, which undergoes deafferentation by tractotomy, may not be essential for processing of nociceptive information from the teeth, oral cavity, and midline facial zones. This findings is contrary to long-held hypotheses concerning facial pain mechanisms. The ability of strychnine and L-dopa to alter nociceptive escape thresholds is consistent with the idea, suggested by Denny-Brown, that facial nociception depends on central summation in the entire spinal trigeminal nucleus from overlapping afferent inputs contained in the trigeminal nerve, other cranial nerves, and the upper cervical nerve roots.

Afferent Pathways↗
PubMed1999

A comparison of four extraction methods for substance P, neurokinin A and calcitonin gene-related peptide from human dental pulp tissue.

Measuring neuropeptides in biological tissues by radioimmunoassay requires efficient extraction that maintains their immunoreactivity. Many different methods for extraction have been described, but there is little information on optimal extraction methods for individual neuropeptides from human dental pulp tissue. The aim was therefore to identify an effective extraction procedure for three pulpal neuropeptides; substance P, neurokinin A and calcitonin gene-related peptide. Tissue was obtained from 20 pulps taken from teeth freshly extracted for orthodontic reasons. The pulp samples were divided into four equal groups and different extraction methods were used for each group. Boiling whole pulp in acetic acid gave the highest overall yield and, in addition, offered an easy and rapid means of pulp tissue processing. The use of protease inhibitors did not increase the recovery of the immunoreactive neuropeptides but did provide the best combination of maximal recoveries and minimal variability. These results should be useful for planning the extraction of these neuropeptides from human pulp tissue in future studies.

Acetic Acid↗
PubMed1991

[Effect of local anesthetics on the dental pulp. Study in rats].

According to the in vitro and in vivo procedures described by Rockert and Pracros, the effect of different local anesthetics (with and without vaso-constrictive solution) have been studied on rat incisor dental pulp. Histological analysis (optical microscopy) of samples (90 rat incisors) showed: A systematic pulp response with concentrations up to 2%. This response correspond with a toxic reaction on the respiratory activity of pulp cells; A highest response with solutions containing a vaso-constrictor additive; An increasing response according to the nature of the anesthetic solution.

4-Aminobenzoic Acid↗
PubMed2001

The in vitro and in vivo influence of 4-META/MMA-TBB resin components on dental pulp tissues.

The purpose of this study was to qualitate the penetration of the major components of 4-META/MMA-TBB adhesive resin (4-META resin) and to characterize their influence on the in vitro and in vivo wound healing of dental pulp tissues. Fresh 4-META resin was applied to rabbit mesentery; its components penetrated the mesentery to form three of layers, depending on the amounts of monomer components in the tissue. The superficial layer was a soft-tissue hybrid layer (STHL), the intermediate layer contained small particles of polymerized 4-META resin, while the deepest layer contained unpolymerized monomer components including MMA and butanol, which were detected by gas chromatography (GC). To characterize the in vivo effects of the deepest layer, we immersed the pulp tissue in MMA or in 5% 4-META/MMA and autotransplanted it to placement beneath a rabbit kidney capsule. The MMA-immersed pulp was positive for osteocalcin and presented osteodentin formation at 7 days, as did the untreated control pulp tissue. In contrast, the 5% 4-META/MMA-immersed pulp collapsed into the cell-deficient fibrous connective tissue, with slight calcification by 7 days and less osteodentin formation at 14 days. Analysis of these data suggests that MMA does not inhibit osteogenic activity of pulp tissue, while 5% 4-META/MMA does inhibit osteogenic activity to some extent.

Acrylic Resins↗
PubMed1996

Toxicity of camphorated phenol and camphorated parachlorophenol in dental pulp cell culture.

The toxicity of phenol, parachlorophenol, camphorated phenol, camphorated parachlorophenol, and camphor was evaluated using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) colorimetric assay on established rat dental pulp cells (RPC-C2A). RPC-C2A cells at the confluent stage were incubated for 24 h in an experimental medium containing each compound at different concentrations. All tested drugs showed cytotoxicity in the MTT assay in a concentration-dependent manner. It is believed that camphor is a vehicle, and it reduces the toxicity of phenol and parachlorophenol. However, camphor itself showed cytotoxicity, and the addition of camphor increased the toxicity of phenol and parachlorophenol, reconfirming the cytotoxicity of these classical antiseptics.

Analysis of Variance↗
PubMed2002

Alpha-smooth-muscle actin in and contraction of porcine dental pulp cells.

The finding of expression of a muscle actin isoform, alpha-smooth-muscle actin (SMA), by the stromal cells of several tissues prompted this study of SMA expression by cells derived from the porcine dental pulp. The SMA content of the cells increased with time in culture. These SMA-containing cells were found to have the capability to contract a collagen-glycosaminoglycan analog of extracellular matrix in vitro.

Actins↗
PubMed1995

Immunolocalization of fibronectin during the early response of dog dental pulp to demineralized dentine or calcium hydroxide-containing cement.

The role of fibronectin during the events initiating the post-developmental histogenesis of dentine was investigated by exposing the pulp to implants of autogenous demineralized dentine or calcium hydroxide-containing cement for short periods. Implants exposed for 3 days were processed for immunoelectron-microscopic analysis of fibronectin adsorption on to their surfaces. The localization of fibronectin in the critical area of interaction was examined by immunofluorescence 6, 14 and 21 days after implantation. Heavy adsorption of fibronectin on to the dentine implants and the crystalline structures that had been deposited on the cement implants was demonstrated. Positive fluorescence was consistently seen around dentine implants. Strongly immunopositive fibroblast-like cells and weakly reactive, differentiating odontoblast-like cells were found in association with the implanted matrix. Uncalcified matrix secreted by the polarized or non-polarized cells was consistently rich in fibronectin. Fibroblast-like cells exhibiting intense immunoreaction only at 14 and 21 days were mainly associated with the crystalline precipitates on the cement surfaces or within the surrounding pulp. The findings indicate that the specific inductive effects of demineralized dentine on pulp cells are initiated by exposure of the pulp to a fibronectin-containing surface; adhesion of pulp cells and synthesis of a fibronectin-rich matrix characterize the development of new dentine. The reparative response to non-specific inductive influences such as calcium hydroxide seems to be mediated by progressive enhancement of fibronectin synthesis in pulp cells.

Adsorption↗