Ampicillin concentrations in human serum, gingiva, mandibular bone, dental follicle, and dental pulp following a single oral administration of bacampicillin

Ninety-six patients who underwent the extraction of impacted mandibular third molars in a nonfasting state were given a single oral dose of bacampicillin preoperatively. Specimens of serum from venous blood (n = 107), gingiva (n = 57), mandibular bone (n = 68), dental follicle (n = 56), and dental pulp (n = 43) were obtained during the operation and assayed for ampicillin content. The mean peak concentrations in serum, gingiva, mandibular bone, dental follicle, and dental pulp all occurred approximately 90 minutes after administration. The concentration ratios of the tissues to the corresponding serum at the peak time were 0.50, 0.20, 0.34, and 0.61, respectively. Bacampicillin showed good absorption by the intestine, and sufficient concentrations of the resulting metabolite, ampicillin, were found in the oral tissues.     

Ampicillin concentrations in human radicular granuloma following a single oral dose of bacampicillin.

Ampicillin concentrations in human serum and radicular granulomas of 42 patients were determined after a single oral dose of bacampicillin (equivalent to 500 mg of ampicillin). Although wide variations were found among both serum and radicular granuloma ampicillin concentrations, measurable concentrations were found in all cases. The mean peak ampicillin concentrations in serum and radicular granulomas occurred at identical times, 1.5 hours, and were 11.19 micrograms/mL (range, 1.30 to 21.00 micrograms/mL) and 5.12 micrograms/g (range, 0.50 to 10.50 micrograms/g), respectively. The mean radicular granuloma/serum ampicillin concentration ratio at the peak time was 0.42. Ampicillin concentrations in radicular granulomas exceeded most of the minimum inhibitory concentrations for bacteria commonly isolated from odontogenic infections.     

Concentrations of ampicillin in human serum and mixed saliva following a single oral administration of lenampicillin, and relationship between serum and mixed saliva concentrations

The concentrations of ampicillin in serum and mixed saliva after a single oral administration of lenampicillin (500 mg) were determined by the paper disc method. The samples of serum and mixed saliva were obtained at 1, 2, 3 and 4 h after administration. The highest concentrations of ampicillin in serum and mixed saliva occurred 1 h after administration of lenampicillin, and were 11.55 and 0.060 micrograms/ml, respectively. A significant correlation coefficient between the concentrations of ampicillin in serum and mixed saliva, r = 0.71, P less than 0.001, was found.     

Lipopolysaccharide stimulates histamine-forming enzyme (histidine decarboxylase) activity in murine dental pulp and gingiva

To examine the potential role of the histamine-forming enzyme, histidine decarboxylase (HDC), in oral inflammation and disease, we studied HDC activity in oral tissue after induction by bacterial agents. Following injection of E. coli-derived lipopolysaccharide (LPS) into mice, we measured the quantitative changes in HDC activity over time in dental pulp and gingiva. Oral tissue taken from individual mice was insufficient for detecting precise HDC activity, thus, we combined dental pulp or gingival tissues from four mice and assayed them over the course of 24 h. Our results indicate that LPS stimulated marked elevations of HDC activity in dental pulp and gingiva. This increase reached a maximum at 6 h after LPS injection and remained detectable at for least 24 h. Since mast cells are known to produce histamine through a difference mechanism than HDC induction, we compared LPS-induced HDC activity in dental pulp and gingiva to that in ear skin (a tissue rich in mast cells) and liver (a tissues lacking in mast cells). LPS also induced a marked increase in the HDC activity in liver and ear skin at 6 h after LPS injection. By contrast, saline injection had no effect on the HDC activity in any of the four tissues, although basal levels of HDC activity in ear skin was markedly higher than basal HDC activity in the other three kinds of tissues. Still, the relative increase in LPS-induced HDC activity in dental pulp and gingiva were much greater than that in ear skin. Since liver are devoid of mast cells and ear skin is considered the tissue richest in mast cells, the differences in HDC activity between tissues indicates that histamine induced by LPS may be produced by cells other than mast cells through another mechanism of action. These results also suggest that histamine produced in oral tissues in response to bacterial agents such as LPS could be involved in development of pulpitis or gingivitis (periodontitis), the most common diseases in the dental clinic, and that efforts to inhibit HDC activity, which elevates histamine levels in oral tissues, might offer the basis for novel treatment strategies.     

The induction of oxidative stress, cytotoxicity, and genotoxicity by dental adhesives.

OBJECTIVES: Polymerized dental resin materials release residual monomers that may interact with pulp tissues. We hypothesized that dental adhesives might cause cytotoxicity in pulp cells via the generation of reactive oxygen species (ROS), which may also contribute to genotoxic effects in vitro. METHODS: For cytotoxicity testing, transformed human pulp-derived cells were exposed to extracts of primers and bonding agents of Clearfil SE bond, Clearfil Protect bond, AdheSE, Prompt L-Pop, and Excite for 24h. The cytotoxicity of the same materials was also analyzed in a dentin barrier test device using three-dimensional pulp cell cultures. The generation of ROS in monolayer cultures was measured after a 1h exposure period by flow cytometry (FACS), and genotoxicity as indicated by the formation of micronuclei was determined in V79 cells after a 24h exposure period. RESULTS: The dentin primers and bonding agents decrease cell survival in a dose-related manner. Cytotoxicity of bonding agents based on concentrations which caused 50% cell death (EC50) were ranked as follows: Excite (0.16 mg/ml)>AdheSE bond (0.30 mg/ml)>Clearfil Protect bond (0.35 mg/ml)>Clearfil SE bond (0.37 mg/ml), and Prompt L-Pop bond (0.68 mg/ml). Dentin primers were about 10-fold less effective. In contrast, no cytotoxic effects of the dental adhesives were observed in a dentin barrier test device. Yet, all dental adhesives increased the amounts of ROS about fivefold in pulp cells in a dose-related manner, and, again, the bonding agents were more efficient than the dentin primers. Finally, the number of micronuclei was increased about sixfold by extracts of the AdheSE primer. SIGNIFICANCE: Our results suggest that the cytotoxic potencies demonstrated by these materials might be of clinical relevance, since all dental adhesives disturbed the cellular redox state of pulp cells in monolayer cultures. As a result, the concentrations of biologically active ingredients of some of the agents may be high enough to modify pulp cell metabolism when the materials are used in deep cavities or directly contact pulp tissue.     

Concentration of azidocillin, erythromycin, doxycycline and clindamycin in dental alveolar serum after single oral doses.

Treatment of osteitis in the mandible after surgery is still a clinical problem. Levels of four antibiotics--azidocillin, erythromycin, doxycycline, and clindamycin--were measured in serum and dental alveolar serum in 42 patients undergoing oral surgery. The systemic serum concentrations were higher than the dental alveolar serum concentrations in all patients. The maximal concentration in the alveolar serum for azidocillin was 6.0-12.0 microng/ml, for erythromycin 0.7-1.3 microng/ml, for doxycycline 2.8-3.6 microng/ml, and for clindamycin 2.0-2.8 microng/ml. When the dental alveolar serum concentrations of the various antibiotics were related to their range of inhibitory concentrations for microorganisms isolated from mandibular osteitis, it was noticed that each drug achieved levels sufficient to inhibit most strains.     

A quantitative examination of immunoglobulins in bovine gingiva and dental pulp.

Mandibles of 4-month-old and 14- to 18-month-old freshly slaughtered steers were utilized to quantitate the immunoglobulin content of the dental pulp and gingiva. Using a single radial immunodiffusion technique, IgG was found in lower concentrations in the pulp and gingiva than in sera. IgG was used as a monitor of relative immunologic activity. When mandibles of older steers were examined, there was an increase in gingival concentrations of IgG and a decrease in pulpal concentrations of IgG. The steer provided an animal model system for the study of immunoglobulin levels in normal dental pulp and gingiva.     

Variation of telomeric DNA content in gingiva and dental pulp

Objective

The purpose of the present study was to examine the age- and tissue-related variations of the telomere length in gingiva and dental pulp of donor patients.

Design

We quantified the relative telomeric DNA content corresponding to the telomere length in gingiva or dental pulp from donor patients (male and female, aged at 19–68) by using genomic DNA of oral tissues in dot-blot hybridization with telomere-specific probe.

Results

Telomeric DNA content in the dental pulp showed a negative correlation with the age of donor patients, with smaller telomeric DNA content observed in the elders (p < 0.05). In age-matched gingival samples, the average telomeric DNA content was not significantly different between male and female donors. In the age- and gender-matched samples, telomeric DNA content was significantly greater (p < 0.001) in dental pulp than in gingiva.

Conclusion

The telomere length is greater in the dental pulp than in the gingiva. In the dental pulp, but not in the gingiva, telomere length shortens with age.     

Macrophages, dendritic cells and T lymphocytes in rat buccal mucosa and dental pulp following 5-fluorouracil treatment

Cancer chemotherapeutic drugs may affect immunocompetent cells of oral soft tissues, causing an impaired capacity to induce immune defence reactions. This study was designed to investigate changes in the number of macrophages, dendritic cells and T lymphocytes in the oral mucosa and dental pulp following treatment with the antineoplastic agent 5-fluorouracil (5-FU). Rats were given 5-FU (30 mg/kg or 50 mg/kg) i.v. on days 0, 1, 2, 5, 6 and 7. The number of cells in buccal epithelium and dental pulp expressing ED2, MHC class II, or CD2 molecules was analyzed following immunohistochemical peroxidase staining. Major histocompatibility complex (MHC) class II molecules were analyzed in epithelial sheets and in epithelial cell suspensions by flow cytometry. Increasing concentrations of 5-FU changed the morphology of the epithelial Langerhans cells with a reduced dendritic appearance as the most prominent feature. At 50 mg/kg of 5-FU, the oral epithelium detached from the connective tissue at the basement membrane. MHC class II molecule-expressing cells were reduced in number in the lamina propria of the buccal mucosa and in the dental pulp after both low and high dose of 5-FU, but only after high dose in the epithelium. The number of ED2- and CD2-expressing cells in the dental pulp was only slightly reduced by 5-FU treatment at both low and high dose, while these cells decreased in number in the oral mucosa. The varying sensitivity to 5-FU by macrophages, dendritic cells, and T cells depending on the tissues in which they reside may be due to differences in cell origin or differences in antigenic load.     

Immunohistochemical localization of collagenase inhibitor in bovine dental pulp, pulp cells in monolayer culture, and in some oral connective tissues

The development of an antiserum, monospecific to the collagenase inhibitor, from bovine dental pulps permitted localization of immunoreactive inhibitor protein, by means of both immunofluorescence and immunoperoxidase-staining techniques in sections of bovine dental pulps. The immunoreactive inhibitor protein in bovine dental pulps is present both in cells and extracellular matrices. When cultured in Eagle minimal essential medium, coronal pulps from bovine-unerupted teeth were shown, by assay of the medium, to produce only about 1/10 of the amount of inhibitor produced by the root pulps. When compared by immunohistochemical observation, however, essentially no differences in fluorescent activity was found between coronal and root pulps. Specific cytoplasmic staining was seen both in explanted root-pulp tissues and in immature fibroblast-like pulp cells from monolayer cell cultures of bovine root pulps, which indicate that the pulp cells are responsible for inhibitor production. Sections of dental follicle and gingiva from the same animal, showed a distribution of immunoreactive inhibitor protein similar to that in dental pulps.     

Diabetes induces metabolic alterations in dental pulp

Diabetes can interfere in tissue nutrition and can impair dental pulp metabolism. This disease causes oxidative stress in cells and tissues. However, little is known about the antioxidant system in the dental pulp of diabetics. Thus, it would be of importance to study this system in this tissue in order to verify possible alterations indicative of oxidative stress. The aim of this study was to evaluate some parameters of antioxidant system of the dental pulp of healthy (n = 8) and diabetic rats (n = 8). Diabetes was induced by streptozotocin in rats. Six weeks after diabetes induction, a pool of the dental pulp of the 4 incisors of each rat (healthy and diabetic) was used for the determination of total protein and sialic acid concentrations and catalase and peroxidase activities. Data were compared by a Student t test (p 相似文献   

Ropivacaine for dental anesthesia: a dose-finding study.

PURPOSE: The purpose of this study was to determine the optimal concentration and volumes of ropivacaine for dental anesthesia as regards onset and duration of action. SUBJECTS AND METHODS: Thirty healthy individuals with a mean age of 32 years participated in the study on a voluntary basis. All subjects received a ropivacaine injection in 1 of 3 randomized concentrations (2.0, 5.0, or 7.5 mg/mL) for infiltration anesthesia and mandibular nerve block in a double-blind manner. The onset time and duration of anesthesia were assessed by electric pulp test, pinprick test of the gingiva, and presence of feeling of numbness of the lip. RESULTS: Regardless of dose, only 5 patients received pulpal anesthesia after infiltration, but all 3 concentrations anesthetized the gingiva and upper lip. The onset of pulpal anesthesia occurred less than 5 minutes after injection and lasted for 4 to 58 minutes. Pinprick anesthesia lasted for 8 to 48 minutes, and numbness of the upper lip lasted 1 to 4 hours. The effectiveness of the mandibular nerve block with regard to pulpal anesthesia was dose dependent. Only ropivacaine at 7.5 mg/mL produced sufficient anesthesia. The onset of pulpal anesthesia occurred less than 10 minutes after injection and lasted for 2 to 6 hours. Pinprick anesthesia lasted for 3 to 6 hours and numbness of the lower lip lasted for 5 to 9 hours. CONCLUSION: This study shows that ropivacaine could be useful as a local anesthetic for mandibular nerve block in dentistry and that the very long duration of both pulpal and soft tissue anesthesia may be favorable in reducing postoperative pain.     

Immunomodulatory properties of dental tissue‐derived mesenchymal stem cells

In addition to their well‐established self‐renewal and multipotent differentiation properties, mesenchymal stem cells (MSCs) also possess potent immunomodulatory functions both in vitro and in vivo, which render them a potential novel immunotherapeutic tool for a variety of autoimmune and inflammation‐related diseases. The major mechanisms may involve (1) the secretion of an array of soluble factors such as prostaglandin E₂ (PGE₂), indoleamine 2, 3‐dioxygenase (IDO), transforming growth factor‐β (TGF‐β), and human leukocyte antigen G5 (HLA‐G5); (2) interactions between MSCs and immune cells such as T cells, B cells, macrophages, and dendritic cells. Recently, increasing evidence has supported that MSCs derived from dental tissues are promising alternative sources of multipotent MSCs. We here provide a thorough and extensive review about new findings in the immunomodulatory functions of MSCs derived from several dental tissues, including dental pulp, periodontal ligament, gingiva, exfoliated deciduous teeth, apical papilla, and dental follicle, respectively. The immunomodulatory properties of dental MSCs place them as a more accessible cell source than bone marrow‐derived MSCs for cell‐based therapy of immune and inflammation‐related diseases.     

表皮生长因子在牙齿萌出通道形成中的作用研究

目的:研究表皮生长因子(EGF)在牙齿萌出过程中,是否参与软、硬组织通道的形成。方法:①免疫组化法检测表皮生长因子及其受体在出生后13、15 d以及成年小鼠下颌第一磨牙萌出部位口腔黏膜的表达变化;②原代培养Wistar大鼠牙囊细胞,选择生长良好的第3代细胞,MTT法筛选EGF作用于牙囊细胞的较佳效应浓度。将第3代牙囊细胞以1×105/孔接种到培养皿中,加入最佳浓度的EGF孵育0.5、1、3、6 h后,Trizol一步法分别提取总RNA,采用反转录聚合酶链反应(RT-PCR)检测同一浓度的EGF作用不同时间后,牙囊细胞MCP-1 mRNA的表达变化。结果:①牙萌出时,EGF在萌出牙齿冠方黏膜的上皮层呈弱阳性表达,表皮生长因子受体(EGFR)在口腔上皮全层呈强阳性表达。而牙萌出后,EGF的表达集中于口腔黏膜的固有层,EGFR的表达集中于上皮基底层;②在EGF浓度为5～10 ng/mL时,对牙囊细胞的增殖具有明显促进作用(P<0.05),其中10 ng/mL促进作用最强。牙囊细胞与10 ng/mL的EGF共同孵育0.5、1、3、6 h均能明显促进牙囊细胞MCP-1 mRNA的表达(P<0.05),其中3 h时促进作用最强,以后逐渐恢复,但仍比对照组高(P<0.05)。结论:EGF及其受体可能促进萌出牙齿冠方实性上皮团的形成;适当浓度的EGF能显著增加牙囊细胞的增殖活性,并上调牙囊细胞中MCP-1 mRNA的表达。     

IGF-1对小鼠牙囊细胞生物学特性的影响

目的:探讨胰岛素样生长因子-1(IGF-1)对小鼠牙囊细胞增殖、蛋白含量及分化能力影响。方法:将第3代小鼠牙囊细胞与不同浓度IGF-1(0.005、0.01、0.05、0.1、0.5 mg/L)共孵育后,测定IGF-1对细胞增殖、碱性磷酸酶活性、总蛋白含量的影响;并用Von Kossa法检测0.05和0.1 mg/L的IGF-1对牙囊细胞矿化结节形成能力的影响。结果:在0.05~0.1 mg/L的浓度范围内,IGF-1能显著促进牙囊细胞的增殖,使ALP活性及总蛋白含量增加(P<0.01),但三者的最佳效应浓度有所差异,当浓度升高至0.5 mg/L时,促进效应下降,与对照组无显著性差异(P>0.05);0.05和0.1 mg/L的IGF-1均能显著促进牙囊细胞矿化结节的形成(P<0.05,与对照组相比)。结论:合适浓度的IGF-1能促进牙囊细胞的增殖,增加蛋白含量及向成骨细胞(成牙骨质细胞)方向分化的能力。     

Gene expression of potential tooth eruption molecules in the dental follicle of the mouse

Tooth eruption requires alveolar bone resorption and the presence of the dental follicle, a loose connective tissue sac that surrounds each tooth. This bone resorption involves the follicle in that mononuclear cells enter the follicle to form osteoclasts which resorb bone to form the eruption pathway. In the rat first mandibular molar, probable eruption genes, CSF-1, c-fos, NFkappaB and MCP-1, are expressed maximally in the dental follicle at day 3 postnatally. This correlates with the time of peak influx of mononuclear cells into the follicle. In the mouse, the first peak influx of mononuclear cells into the first mandibular molar is at day 5 postnatally, and this study demonstrates that all four of the above resorption molecules are maximally expressed at this time in the dental follicle. Thus, this work suggests that these molecules may play a role in the cellular events of eruption (mononuclear cell influx and osteoclast formation) in the mouse molar at day 5 postnatally just as they do at day 3 in the rat molar. These results provide a standard for future studies on eruption in the mouse molar and extends the number of species in which putative eruption molecules are expressed at a critical time of eruption.     

Characterization of dental follicle cells in developing mouse molar.

Dental follicle has been implicated as the origin of alveolar bone, cementum and periodontal ligament, but there is no direct evidence of their cellular lineage. The present pilot study was designed to characterize the phenotype of cultured cells obtained from the dental follicle of neonatal mouse molars. Developing mandibular molars from 6-day-old CD-1 mice were subjected to 1% trypsin in Hank's balanced salt solution. After trypsinization, the dental follicle was enucleated from the tooth germ and separated from the associated epithelial root sheath. Pure dental follicle tissue was cultured in alpha-minimal essential medium containing 10% fetal bovine serum and antibiotics. The nature of the cultured follicle cells was determined in situ by immunocytochemical staining for type I and III collagen, fibronectin, and alkaline phosphatase expression. Earlier phenotypic markers for mineralization such as bone sialoprotein and osteopontin were also examined by in situ hybridization of matched molar tissues. The extracellular matrix proteins (such as type I collagen and fibronectin) were moderately expressed cytochemically. However, type III collagen was strongly stained. Gene expression of bone sialoprotein and osteopontin was detected in sections of mouse molars of similar age. The ALPase activity showed moderate to strong intensity in these primary cultured cells and responded to 1,25(OH)2 vitamin D3 treatment. Cytokeratin stains were not noted in these cells. In conclusion, the 6-day-old dental follicle cells exhibit partial characteristics of a mineralized tissue-forming phenotype even though the expression of osteopontin, type I collagen and fibronectin was low at this stage.     

表皮生长因子对大鼠牙囊细胞单核细胞趋化蛋白-1表达的影响

目的:研究表皮生长因子(EGF)对体外培养的大鼠牙囊细胞单核细胞趋化蛋白-1(MCP-1)表达的影响.方法:原代培养Wistar大鼠牙囊细胞,选择生长良好的第3代细胞,分别加入不同浓度的EGF与牙囊细胞共孵育5d,MTT法对比观察不同浓度的EGF对牙囊细胞增殖活性的影响,筛选EGF作用于牙囊细胞的最佳效应浓度.将第3代牙囊细胞以1×105/孔接种到培养皿中,加入最佳浓度的EGF孵育0、0.5、1、3、6h后,Trizol一步法分别提取总RNA,采用反转录聚合酶链反应(RT-PCR)检测同一浓度的EGF作用不同时间后,牙囊细胞MCP-1 mRNA的表达变化.数据采用SPSS13.0软件包进行方差分析.结果:在EGF浓度为5～10 ng/ml时,牙囊细胞的增殖活性显著增高(P＜0.05),10 ng/ml时达到最高(P＜0.01).牙囊细胞与10ng/ml的EGF共同孵育3 h,MCP-1 mRNA表达最高(P＜0.01),以后逐渐恢复,但仍比对照组高(P＜0.05).结论:EGF与其受体结合,可作用于牙囊细胞,适当浓度的EGF能显著增加牙囊细胞的增殖活性,并且EGF可通过上调牙囊细胞中MCP-1 mRNA的表达.促进单核细胞聚集.调节牙的萌出.     

骨髓间充质干细胞向牙髓组织迁移体内模型的构建

目的：构建一种骨髓间充质干细胞（bone marrow mesenchymal stem cells,BMMSCs）向牙髓等口腔组织迁移分化的体内模型,为进一步研究BMMSCs迁移、归巢机制从而诱导其修复、再生口腔组织奠定基础。方法：将第1代绿色荧光蛋白（Green flurensence protein,GFP）转基因小鼠的BMMSCs与野生型C57BL6小鼠的全骨髓细胞按一定比例混合后,尾静脉注射入亚致死量照射24h后的16只同品系小鼠体内（GFP-BMMSCs：2×105/只;BMCs：2×106/只）,28d后随机选取6只嵌合小鼠,检测其股骨BMMSCs中GFP＋BMMSCs细胞的比例。对同一处理组剩余小鼠右下颌磨牙牙髓施加刺激,7d后行多聚甲醛心脏灌注,并采集标本,常规脱钙处理后以自体左侧磨牙作为对照,组织学观察比较牙髓中荧光细胞数量改变。结果：嵌合模型股骨BMMSCs中GFP＋的比例为（76.32±3.46）%,口腔刺激侧牙髓中荧光细胞数量明显多于同一个体对照侧（P〈0.05）。结论：以荧光细胞作为示踪标记的骨髓移植动物可作为有效的研究模型探索骨髓间充质干细胞在体向牙髓等口腔组织迁移分化机制。