Split-mouth evaluation of connective tissue graft with or without enamel matrix derivative for the treatment of isolated gingival recession defects in dogs.

OBJECTIVES: The potential additive effect of an enamel matrix derivative (EMD) to a subepithelial connective tissue graft (CTG) for recession coverage is still controversially discussed. Therefore, the aim of this study was to histologically evaluate the healing of gingival recessions treated with coronally advanced flap (CAF) and CTG with or without EMD in dogs. MATERIALS AND METHODS: Gingival recession defects (5 mm wide and 7 mm deep) were surgically created on the labial side of bilateral maxillary canines in 7 dogs. After 8 weeks of plaque accumulation and subsequent 2 weeks of chemical plaque control, the 14 chronic defects were randomized to receive either CAF with CTG (CAF/CTG) or CAF with CTG and EMD (CAF/CTG/EMD). The animals were sacrificed 10 weeks after reconstructive surgery for histologic evaluation. RESULTS: Treatment with CAF/CTG/EMD demonstrated statistically significantly better results in terms of probing pocket depth reduction (P < 0.05) and clinical attachment level gain (P < 0.001). The length of the epithelium was statistically significantly shorter in the CAF/CTG/EMD group than in the CAF/CTG group (1.00 ± 0.75 mm vs. 2.38 ± 1.48 mm, respectively, P < 0.01). Cementum formation was statistically significantly greater in the CAF/CTG/EMD group than following treatment with the CAF/CTG group (3.20 ± 0.89 mm vs. 1.88 ± 1.58 mm, respectively, P < 0.01). The CAF/CTG/EMD group showed statistically significantly greater complete periodontal regeneration (i.e., new cementum, new periodontal ligament, and new bone) than treatment with CAF/CTG (0.54 ± 0.73 mm vs. 0.07 ± 0.27 mm, respectively, P < 0.05). CONCLUSION: Within their limits, the present findings indicate that the additional use of EMD in conjunction with CAF + CTG favors periodontal regeneration in gingival recession defects. CLINICAL RELEVANCE: The present findings support the use of EMD combined with CTG and CAF for promoting periodontal regeneration in isolated gingival recession defects.

Healing of localized gingival recessions treated with a coronally advanced flap alone or combined with an enamel matrix derivative and a porcine acellular dermal matrix: a preclinical study.

OBJECTIVE: This study aimed to evaluate the effects of a porcine acellular dermal matrix (PADM) with or without an enamel matrix derivative (EMD) on gingival recession defects treated with a coronally advanced flap (CAF) in dogs. MATERIALS AND METHODS: Miller class II gingival recession defects (5 mm wide and 7 mm deep) were surgically created on the labial side of bilateral maxillary canines in 12 dogs. After 8 weeks of plaque accumulation, the 24 chronic defects were randomly assigned to one of the following 4 treatments: CAF, CAF with PADM (CAF/PADM), CAF with EMD (CAF/EMD), and CAF with EMD and PADM (CAF/EMD/PADM). The animals were sacrificed 10 weeks after surgery for histologic evaluation. RESULTS: In all groups, root coverage was obtained to a varying degree. PADM was well incorporated in gingival connective tissue in the CAF/PADM and in the CAF/EMD/PADM groups. The height of newly formed bone was significantly greater in the CAF/EMD/PADM group than in the CAF and CAF/PADM groups. New cementum with periodontal ligament-like tissue was predominantly found in the CAF/EMD and CAF/EMD/PADM groups. The CAF/EMD/PADM group showed the greatest amount of new cementum among the groups examined, although the difference was not statistically significant. CONCLUSION: Within the limitations of the present study, it can be concluded that CAF/EMD/PADM treatment may promote periodontal regeneration in gingival recession defects. CLINICAL RELEVANCE: The present results suggest that the combination of EMD and PADM in conjunction with CAF may represent a promising approach for treating single Miller class II gingival recessions.

Resistin in gingival crevicular fluid and induction of resistin release by Porphyromonas gingivalis lipopolysaccharide in human neutrophils.

BACKGROUND AND OBJECTIVE: Resistin is an adipocytokine that induces insulin resistance and is predominantly expressed in adipocytes and peripheral blood mononuclear cells. Resistin expression increases in inflammatory diseases as well as diabetes mellitus, and is upregulated by bacterial pathogens and proinflammatory cytokines. The aim of this study was to identify resistin in human gingival crevicular fluid, to compare the resistin levels in gingival crevicular fluid between subjects with and without periodontitis and diabetes mellitus and to investigate the regulation of resistin release from human neutrophils by Porphyromonas gingivalis lipopolysaccharide (P-LPS). MATERIAL AND METHODS: Gingival crevicular fluid samples were collected from patients with chronic periodontitis (n = 24), patients with diabetes mellitus-related periodontitis (n = 18) and healthy subjects (n = 21). Resistin in gingival crevicular fluid was determined using western blot analysis and an ELISA kit. The glycated hemoglobin (HbA(1c)) value was obtained from patients with diabetes mellitus-related periodontitis by a medical interview. Human neutrophils were cultured with P-LPS (0-1000 ng/mL), or incubated with inhibitors of actin or microtubule polymerization in the absence or presence of P-LPS. The medium and cellular fractions were used for determination of resistin by ELISA. RESULTS: The resistin level in gingival crevicular fluid from patients with periodontitis or diabetes mellitus-related periodontitis was significantly higher than that of healthy subjects. The resistin level in gingival crevicular fluid was correlated with gingival index score, but not blood HbA(1c) value. The P-LPS increased resistin release from human neutrophils, and its induction was decreased by actin polymerization inhibitors. CONCLUSION: We show, for the first time, the presence of resistin in gingival crevicular fluid. A high resistin level in gingival crevicular fluid samples from periodontitis patients may to some extent be related to P-LPS-induced resistin release from neutrophils.

Analysis of proteins in human gingival crevicular fluid by mass spectrometry.

BACKGROUND AND OBJECTIVE: Gingival crevicular fluid is a bodily fluid transuded from periodontal tissues into the gingival crevice and periodontal pocket, and contains many species of components. Proteins in gingival crevicular fluid have been studied as markers for periodontal diseases. Mass spectrometric analysis is used for the analyses of proteins, lipids, saccharides and metals, and expected as an approach for disease diagnosis. For better analysis of the protein components in gingival crevicular fluid, we investigated proteins in gingival crevicular fluid samples from the healthy gingival crevice and periodontal pocket using mass spectrometry. MATERIAL AND METHODS: Gingival crevicular fluid samples were collected from subjects who gave their informed consent and were periodontally healthy or had diseased pockets. These samples were electrophoretically separated, and each fraction on the gels was analysed by nano liquid chromatography coupled with tandem mass spectrometry. Antimicrobial peptides detected in gingival crevicular fluid were confirmed by western blotting. RESULTS: One hundred and four proteins were detected in gingival crevicular fluid samples from both healthy sites and sites of periodontitis; 64 proteins were contained only in gingival crevicular fluid from healthy sites and 63 proteins were observed only in gingival crevicular fluid from periodontitis sites. These proteins were blood-, cytoskeleton-, immunity-, inflammation- and lipid-related proteins and enzymes. Some proteins, including ceruloplasmin, glycogen phosphorylase, glutathione S-transferase, phosphoglycerate mutase, psoriasin, S100A11 and resistin, were identified for the first time in gingival crevicular fluid. Antimicrobial peptides, such as lactoferrin, α1-antitrypsin, lipocalin, S100A7, S100A8, S100A9 and cathelicidin, were observed by mass spectrometry and western blotting. CONCLUSION: Multiple protein components in gingival crevicular fluid were analysed at the same time using mass spectrometry, and this approach may be useful for the diagnosis of periodontal diseases.

Association between lipoprotein subfraction profile and the response to hepatitis C treatment in Japanese patients with genotype 1b.

Pegylated interferon and ribavirin combination therapy is the standard treatment for patients with chronic hepatitis C (CHC). Some groups have reported a relation between lipid values and response while others have reported that microsomal triglyceride transfer protein, a key enzyme in the assembly and secretion of lipoproteins, was related to hepatitis C virus (HCV). The aim of this study was to investigate the association between the lipoprotein profiles, classified according to size, and hepatitis C treatment and the usefulness for predicting the outcome of treatment. Forty-four patients with CHC (27 men and 17 women) were included in the study. The serum cholesterol and triglyceride (TG) levels in the lipoprotein subclasses were determined using high-performance liquid chromatography with gel permeation columns, which classified lipoproteins into 20 subfractions based on particle size. According to a univariate analysis, those who achieved an sustained viral response (SVR) had a significantly higher serum total cholesterol level, higher cholesterol levels in the low-density lipoprotein subfraction (25.5 nm in diameter) and the very low-density lipoprotein (VLDL) subfraction (44.5 and 36.8 nm), and a higher serum TG level in the VLDL subfraction (44.5 nm), compared with the corresponding values in the non-SVR group. Higher serum cholesterol and TG concentrations in the lipoprotein subfractions were predictive of an SVR to therapy for HCV infection with genotype 1b prior to the start of interferon treatment.

Association between phospholipids and free cholesterol in high-density lipoprotein and the response to hepatitis C treatment in Japanese with genotype 1b.

Pegylated interferon and ribavirin combination therapy is the standard treatment for patients with chronic hepatitis C (CHC), but treatment failure can be difficult to predict. We and others have reported a relation between lipid values and sustained viral responses in patients with CHC. However, the relationship between lipid values and treatment failure has not been previously reported. The present study investigated the association between the profiles of phospholipids and free cholesterol (FC), the main constitutive ingredients of the surface of lipoprotein, classified according to particle size and hepatitis C treatment, and determined the usefulness of these parameters for predicting the outcome of treatment. Fifty-five patients with CHC (33 men and 22 women) were included in the study. The serum total cholesterol, triglyceride, phospholipids, and FC levels in the lipoprotein subclasses were determined using high-performance liquid chromatography with gel permeation columns, enabling the lipoproteins to be classified into 13 subclasses according to particle size. According to a univariate analysis, the treatment failure group had a significantly higher serum phospholipid level overall in the high-density lipoprotein (HDL) and medium HDL fractions as well as a higher serum FC level in the HDL fraction and all HDL subclass fractions compared with the corresponding values in the non-nonvirological response group. Higher serum phospholipid and FC concentrations in the HDL subclasses were predictive of a failure to respond in patients with genotype 1b.

Subcultured odontogenic epithelial cells in combination with dental mesenchymal cells produce enamel-dentin-like complex structures.

We showed in a previous study that odontogenic epithelial cells can be selectively cultured from the enamel organ in serum-free medium and expanded using feeder layers of 3T3-J2 cells. The subcultured odontogenic epithelial cells retain the capacity for ameloblast-related gene expression, as shown by semiquantitative RT-PCR. The purpose of the present study was to evaluate the potential of subcultured odontogenic epithelial cells to form tooth structures in cell-polymer constructs maintained in vivo. Enamel organs from 6-month-old porcine third molars were dissociated into single odontogenic epithelial cells and subcultured on feeder layers of 3T3-J2 cells. Amelogenin expression was detected in the subcultured odontogenic epithelial cells by immunostaining and Western blotting. The subcultured odontogenic epithelial cells were seeded onto collagen sponge scaffolds in combination with fresh dental mesenchymal cells, and transplanted into athymic rats. After 4 weeks, enamel-dentin-like complex structures were present in the implanted constructs. These results show that our culture system produced differentiating ameloblast-like cells that were able to secrete amelogenin proteins and form enamel-like tissues in vivo. This application of the subculturing technique provides a foundation for further tooth-tissue engineering and for improving our understanding of ameloblast biology.

Shear stress facilitates tissue-engineered odontogenesis.

Numerous studies have demonstrated the effect of shear stress on osteoblasts, but its effect on odontogenic cells has never been reported. In this study, we focused on the effect of shear stress on facilitating tissue-engineered odontogenesis by dissociated single cells. Cells were harvested from the porcine third molar tooth at the early stage of crown formation, and the isolated heterogeneous cells were seeded on a biodegradable polyglycolic acid fiber mesh. Then, cell-polymer constructs with and without exposure to shear stress were evaluated by in vitro and in vivo studies. In in vitro studies, the expression of both epithelial and mesenchymal odontogenic-related mRNAs was significantly enhanced by shear stress for 2 h. At 12 h after exposure to shear stress, the expression of amelogenin, bone sialoprotein and vimentin protein was significantly enhanced compared with that of control. Moreover, after 7 days, alkaline phosphatase activity exhibited a significant increase without any significant effect on cell proliferation in vitro. In vivo, enamel and dentin tissues formed after 15 weeks of in vivo implantation in constructs exposure to in vitro shear stress for 12 h. Such was not the case in controls. We concluded that shear stress facilitates odontogenic cell differentiation in vitro as well as the process of tooth tissue engineering in vivo.

A novel culture system for porcine odontogenic epithelial cells using a feeder layer.

The growth of cells in vitro can provide useful models for investigating their behaviour and improving our understanding of their function in vivo. Although the developmental regulation of enamel matrix formation has been comprehensively analysed, the detailed cellular characteristics of ameloblasts remain unclear because of the lack of a system of long-term in vitro culture. Therefore, the establishment of odontogenic epithelial cell lines has taken on a new significance. Here, we report on a novel porcine odontogenic epithelial cell-culture system, which has permitted serial culture of these cells. Epithelial cells were harvested from third molar tooth buds in the fresh mandibles of 6-month-old pigs, and seeded on dishes in D-MEM containing 10% FBS. Before the cells reached confluence, the medium was changed to LHC-9 to select the epithelial cells. When trypsinized epithelial cells were plated together with 3T3-J2 cells as a feeder layer, the epithelial cells grew from single cells into colonies. The colonies then expanded and became confluent, and could be sub-cultured for up to 20 passages. The long-term culture cells expressed mRNA for amelogenin and ameloblastin, as well as enamelysin (MMP-20), which is a tissue-specific gene product unique to ameloblasts. These results show that the system is capable of sustaining the multiplication of odontogenic epithelial cells with the characteristics of ameloblasts.

Replica multichannel polymer chips with a network of sacrificial channels sealed by adhesive printing method.

Replica microchips for capillary array electrophoresis containing 10 separation channels (50 microm width, 50 microm depth and 100 microm pitch) and a network of sacrificial channels (100 microm width and 50 microm depth) were successfully fabricated on a poly(methyl methacrylate) (PMMA) substrate by injection molding. The strategy involved development of moving mask deep X-ray lithography to fabricate an array of channels with inclined channel sidewalls. A slight inclination of channel sidewalls, which can not be fabricated by conventional deep X-ray lithography, is highly required to ensure the release of replicated polymer chips from a mold. Moreover, the sealing of molded PMMA multichannel chips with a PMMA cover film was achieved by a novel bonding technique involving adhesive printing and a network of sacrificial channels. An adhesive printing process enables us to precisely control the thickness of an adhesive layer, and a network of sacrificial channels makes it possible to remove air bubbles and an excess adhesive, which are crucial to achieving perfect sealing of replica PMMA chips with well-defined channel and injection structures. A CCD camera equipped with an image intensifier was used to simultaneously monitor electrophoretic separations in ten micro-channels with laser-induced fluorescence detection. High-speed and high-throughput separations of a 100 bp DNA ladder and phi X174 Hae III DNA restriction fragments have been demonstrated using a 10-channel PMMA chip. The current work establishes the feasibility of mass production of PMMA multichannel chips at a cost-effective basis.

Alpha 2 integrin +807 polymorphism in drug-induced gingival overgrowth.

Alpha2 integrin on fibroblasts is reported to play an important role in the induction of drug-induced gingival overgrowth, which is characterized by excessive accumulation of type I collagen in gingival connective tissue. Silent polymorphism 807 T/C within the alpha2 integrin gene is associated with high/low alpha2 integrin expression. The aim of this study was to test the hypothesis that expression of alpha2 integrin 807 T/C polymorphism correlates with drug-induced gingival overgrowth. A case-control study comparing 136 subjects taking calcium channel blockers (72 with vs. 64 without drug-induced gingival overgrowth) demonstrated that the frequency of the +807 C allele was significantly higher in the case group than in the controls (odds ratio, 3.61; 95% confidence interval, 2.14 - 6.10; P < 0.05). The present findings suggest that the alpha2 +807 C allele is one of the genetic risk factors for drug-induced gingival overgrowth.

Four novel mutations of the connexin 32 gene in four Japanese families with Charcot-Marie-Tooth disease type 1.

DNA-based mutation analysis on the connexin 32 gene was performed in 49 families with Charcot-Marie-Tooth disease (CMT) type 1 but without duplication involving the chromosomal region, 17p12-p11.2. Mutations were identified in five of the 49 families, and four of the five mutations were hitherto undescribed: Va137Met, Glu57His, Arg142Glu, Val177Ala. X-linked CMT sometimes lacks evidence for X-linked transmission and cannot be differentiated from CMT type 2, especially in females with mildly decreased nerve conduction velocity. Therefore, molecular analysis is useful for molecular pathology of their disease.

Intracellular control of gene trafficking using liposomes as drug carriers.

The objective of this review is to summarize some of the critical barriers in gene delivery and recent progress in overcoming such barriers using non-viral carrier systems. Receptor-mediated endocytosis is generally considered to be a principal entering pathway. Therefore, endosomal escape is an essential step for achieving efficient transfection. The nuclear membrane is also a critical barrier in gene delivery and the application of the nuclear localization signal is discussed, based on recent strategies. It is essential to optimize the carrier system, in order to enhance the transfection ability equivalent to a viral system. The importance of developing an intracellular pharmacokinetic model of genes is emphasized in the optimization of non-viral carrier systems.

Direct quantitative analysis of respirable cristobalite on filter by infrared spectrophotometry.

A direct on-filter method in infrared spectrophotometry was investigated for the quantitative analysis of respirable cristobalite. A polypropylene membrane filter was employed for this analysis, because the membrane filter has high transparency and no interference peak in the spectral range to be used (750-250 cm-1). Linear relation between the sample weight and peak height (absorbance) for three specific peaks at 620, 385 and 300 cm-1 of cristobalite were confirmed over the range from 45 to 1,000 micrograms/cm2 for 620 cm-1 peak and 45-2,380 micrograms/cm2 for 385 and 300 cm-1 peaks. The variation of absorbance with the difference of particle size was smaller in filter sample than in potassium bromide pellet sample. As a conclusion, this direct on-filter method can be used for quantitative analysis of cristobalite in airborne dust in working environment.

[A case of facial diplegia due to EB virus infection].

A case of facial diplegia due to EB virus infection is reported. A 56-year-old man developed headache, arthralgia and low grade fever. Two days later he noted dysesthesia of the bilateral extremities. Eight days later, disturbances of bilateral mouth and eye closing appeared, which brought him to our hospital on January 6, 1986. Neurological examinations disclosed bilateral peripheral facial palsy and glove and stocking type sensory impairment. Muscle weakness, pathological reflexes were not noted. Examination of CSF on admission revealed a cell count of 63/mm3 and a protein concentration of 45 mg/dl. The lumbar puncture, done 7 days later, revealed a cell count of 17/mm3, and a protein concentration of 41 mg/dl. Serum Epstein-Barr virus titers were times 40 (VCA IgG) and less than X10 (EBNA) on admission. Nine days later, serum EB virus titer increased to times 160 (VCA IgG). He was diagnosed as having polyneuropathy due to EB virus infection from the clinical manifestations and serum antibody titer for EB virus. EB virus infection produces various neurological manifestations. Facial nerve palsy is reported as one of the rare complications. However, most of these cases are associated with Guillain-Barré syndrome (GBS). As far as we know, only 10 cases of bilateral facial nerve palsy in the absence of GBS have appeared in the literature. In our case, bilateral facial nerve palsy appeared as a part of polyneuropathy in the absence of GBS. EB virus should be considered as one of etiologies of bilateral facial nerve palsy.

[An adult case of purulent meningitis secondary to retropharyngeal and deep neck abscess after treatment of odontogenic infection].

Retropharyngeal and deep neck abscess, which may follow odontogenic infection, is uncommon in adults, but can be fatal. Furthermore, bacterial meningitis secondary to this disorder is extremely rare. A 67-year-old man was brought to our hospital because he had developed neck pain, trismus, and disturbance of consciousness over several days. A few days prior to the appearance of neck pain, he had the periodontitis treated. Based on CSF, cervical X-ray and CT findings, he was diagnosed as having bacterial meningitis secondary to deep neck abscess. Culture of the CSF yielded gram-positive cocci, later identified as Gemella species, that is a rare organism for bacterial meningitis. Although the administration of antibiotics and drainage of the abscess resulted in gradual improvement of the infectious process, neurologically he remained with apallic syndrome. We would like to stress the importance of odontogenic and pharyngolaryngogenic sources as potential foci of purulent meningitis.

Inhibition of fibrous adhesion formation in the temporomandibular joint of tenascin-C knockout mice.

Tenascin-C (TNC) is a large hexameric extracellular matrix glycoprotein that is expressed in developing organs and tumors. It has been reported that TNC is expressed in inflamed synovial membranes and deformed discs of temporomandibular joint (TMJ) disorder. However, the role of TNC in TMJ is not fully known. In this study, the role of TNC in fibrous adhesion formation of TMJ was examined using TNC knockout (TNCKO) mice. Hypermobility was produced by excessive mouth opening method on the TMJ of both wild-type (WT) and TNCKO mice. TMJ wound healing was compared histologically, and the expression of TNC, fibronectin (FN) and α-smooth muscle actin (α-SMA) in the wounded TMJ was examined by immunohistochemical and immunoblot analyses. Based on histologic analysis, fibrous adhesions were observed in the TMJ of both TNCKO and wild-type (WT) mice after excessive mouth opening. However, fibrous adhesion formation in TNCKO mice occurred later than in WT mice. TNC was expressed in the wounded TMJ disc and mandibular fossa. Although FN and α-SMA expression in the TMJ of TNCKO and WT mice was up-regulated after excessive mouth opening, FN and α-SMA protein levels were higher in WT mice at the same time points. In the wounded TMJ, TNC appears to enhance the expression of FN and α-SMA, and a lack of TNC may reduce fibrous adhesion formation in the TMJ. TNC plays an important role in TMJ wound healing, especially for wounds generated by mechanical stress.

Collagen type I matrix affects molecular and cellular behavior of purified porcine dental follicle cells.

We investigated porcine dental follicle cells at the early crown-formation stage and examined the behavior of cells grown in a collagen type I (Col-I) matrix. Clone-porcine dental follicle cells (DFC-I) and controls, viz., dental follicle itself, nonclone-dental follicle cells, periodontal ligament cells (PDLC), and bone marrow stromal cells, were obtained from 6-month-old pigs. DFC-I showed a different gene expression pattern from controls by reverse-transcription polymerase chain reaction analysis. In addition, Col-I treatment enhanced DFC-I proliferation and increased their alkaline phosphatase activity compared with nontreated DFC-I. The expression of periostin, biglycan, and osteocalcin (OCN) in cells growing on collagen was upregulated, similar to the pattern seen in PDLC. DFC-I with and without Col-I treatment were combined with beta-tricalcium phosphate particles and implanted into immunodeficient mice. Significant differences were found in the gene expression patterns of bone sialoprotein, OCN, and periostin in both treated and non-treated implants at 2 and/or 4 weeks. The results showed that Col-I induced the mineralization pathway in these cells. Hard tissue formation was observed in both implant types at 8 weeks. Our results suggest that Col-I facilitates the differentiation of DFC-I along the mineralization process.

Regulation of calprotectin expression by interleukin-1alpha and transforming growth factor-beta in human gingival keratinocytes.

BACKGROUND AND OBJECTIVE: Calprotectin, a heterodimer of S100A8 and S100A9 with antimicrobial properties, is expressed in gingival keratinocytes and plays an important role in innate immunity. Because calprotectin expression is localized in the spinous cell layer of the gingival epithelium, we hypothesized that the expression of calprotectin in keratinocytes is related to the differentiation stage. The aim of the present study was to investigate the relationship between calprotectin expression and keratinocyte differentiation using some factors that regulated its differentiation. MATERIAL AND METHODS: Normal human gingival keratinocytes were isolated from gingival tissues obtained at the extraction of wisdom teeth, and were cultured in serum-free keratinocyte medium supplemented with interleukin-1alpha or calcium, which promote keratinocyte differentiation, and transforming frowth factor-beta (TGF-beta) or retinoic acid, which suppress its differentiation. The expression of S100A8/A9 mRNA and the production of calprotectin in normal human gingival keratinocytes were examined by northern blotting and enzyme-linked immunosorbent assay, respectively. The expression of cytokeratin 14, involucrin and filaggrin (marker proteins of keratinocyte differentiation) was investigated by immunohistochemical staining, and the DNA-binding activity of CCAAT/enhancer binding protein alpha (C/EBPalpha), a transcription factor, was examined by electrophoretic mobility shift assay. RESULTS: The expression of S100A8/A9 mRNA and the production of calprotectin were increased by interleukin-1alpha and calcium, but decreased by TGF-beta. RA inhibited the expression of S100A8/A9 and keratinocyte differentiation, which were induced by interleukin-1alpha. C/EBPalpha DNA-binding activity in normal human gingival keratinocytes was enhanced by interleukin-1alpha and calcium, but suppressed by TGF-beta. CONCLUSION: The present study suggests that calprotectin expression is related to keratinocyte differentiation and that C/EBPalpha is a regulator of calprotectin expression in keratinocytes.

Side population cells expressing ABCG2 in human adult dental pulp tissue.

AIM: To investigate the presence of side population (SP) cells by the Hoechst exclusion method in human adult dental pulp tissue. METHODOLOGY: Human adult dental pulp-derived cells were generated from third molar teeth. The cells were stained with Hoechst 33342 and sorted into SP cells or non-SP cells [main population (MP) cells]. Both cell types were compared with cell growth and RT-PCR analyses. RESULTS: SP cells that express ABCG2, Nestin, Notch-1 and alpha-smooth muscle actin were found at frequencies ranging from 0.67% to 1.02%. This SP profile disappeared in the presence of verapamil. These SP cells expressed dentine sialophosphoprotein and dentine matrix protein-1 when cultured in osteogenic medium. CONCLUSION: Human adult dental pulp tissue contains SP cells that differentiate into odontoblast-like cells.