Targeting hepatocyte growth factor in epithelial-stromal interactions in an in vitro experimental model of human periodontitis.

Periodontitis is a chronic inflammatory disease leading to progressive connective tissue degradation and loss of the tooth-supporting bone. Clinical and experimental studies suggest that hepatocyte growth factor (HGF) is involved in the dysregulated fibroblast-epithelial cell interactions in periodontitis. The aim of this study was to explore effects of HGF to impact fibroblast-induced collagen degradation. A patient-derived experimental cell culture model of periodontitis was applied. Primary human epithelial cells and fibroblasts isolated from periodontitis-affected gingiva were co-cultured in a three-dimensional collagen gel. The effects of HGF neutralizing antibody on collagen gel degradation were tested and transcriptome analyses were performed. HGF neutralizing antibody attenuated collagen degradation and elicited expression changes of genes related to extracellular matrix (ECM) and cell adhesion, indicating that HGF signaling inhibition leads to extensive impact on cell-cell and cell-ECM interactions. Our study highlights a potential role of HGF in periodontitis. Antagonizing HGF signaling by a neutralizing antibody may represent a novel approach for periodontitis treatment.

Fibroblast VEGF-receptor 1 expression as molecular target in periodontitis.

AIM: Degradation of extracellular matrices is an integral part in periodontitis. For antagonizing this pathophysiological mechanism, we aimed at identifying gene expression profiles in disease progression contributing periodontitis-associated fibroblasts (PAFs) versus normal gingival fibroblasts to determine their molecular repertoire, and exploit it for therapeutic intervention. MATERIALS AND METHODS: Applying an exploratory analysis using a small number of microarrays in combination with a three dimensional (3D) in vitro culture model that incorporates some aspects of periodontitis, PAFs were initially characterized by gene-expression analyses, followed by targeted gene down-regulation and pharmacological intervention in vitro. Further, immunohistochemistry was applied for phosphorylation analyses in tissue specimens. RESULTS: PAFs were characterized by 42 genes being commonly up-regulated >1.5-fold, and by five genes that were concordantly down-regulated (<0.7-fold). Expression of vascular endothelial growth factor (VEGF)-receptor 1 (Flt-1) was highly enhanced, and was thus further explored in in vitro culture models of periodontal fibroblasts without accounting for the microbiome. Phosphorylation of the VEGF-receptor 1 was enhanced in PAFs. Receptor inhibition by a specific VEGF-receptor inhibitor or intrinsic down-regulation by RNAi of the VEGF-receptor kinase in 3D gel cultures resulted in significant reduction in collagen degradation associated with increased tissue inhibitor of metalloproteinase expression, suggesting that Flt-1 may contribute to periodontitis. CONCLUSION: Based on the finding that VEGF-receptor kinase inhibition impaired collagen degradation pathways, Flt-1 may represent a candidate for therapeutic approaches in periodontitis.

Evaluation of bioartificial renal tubule device prepared with human renal proximal tubular epithelial cells cultured in serum-free medium.

Bioartificial renal tubule devices (BTD) use cell therapy to improve conditions commonly observed in recipients of artificial kidneys for treatment of kidney diseases. We previously reported significant improvement of the condition of acute kidney injury (AKI) animals after treatment with BTD prepared with lifespan-extended human renal proximal tubular cells (hRPTEC). However, a major obstacle to use of BTD for patients is their biological safety, because hRPTEC are cultured in medium containing fetal calf serum. To establish the biological safety of BTD, we prepared BTD with lifespan-extended hRPTEC cultured in a newly developed serum-free medium and compared these with BTD prepared with hRPTEC cultured in serum-containing conventional medium. Lifespan-extended hRPTEC cultured in serum-free medium (hRPTEC-SFM) can proliferate similar to hRPTEC cultured in serum-containing conventional medium (hRPTEC-CM). Comparison of leakage and of reabsorption of small molecules for BTD prepared with hRPTEC-SFM (BTD-SFM) with those for our previous BTD prepared with hRPTEC-CM (BTD-CM) showed transportation in these two types of BTD was almost identical. When AKI goats were treated with BTD-SFM for 26 h, increase of survival time and reduction of cytokine expression in blood cells were almost same as for AKI goats treated with BTD-CM. Quantification of the expression of some genes of hRPTEC in BTD revealed significant changes during BTD treatment for AKI goats. In conclusion, lifespan-extended hRPTEC-SFM work as well as hRPTEC-CM, and the biological safety of BTD for patients could be elevated without loss of function by preparation from hRPTEC-SFM.

Occupational Lung Disease Caused by Exposure to Polytetrafluoroethylene.

We herein report a 45-year-old-man with multiple foreign body granulomas in the lungs caused by polytetrafluoroethylene (PTFE). A mass in the right lower lobe of the lung and bilateral centrilobular lung nodules were found unexpectedly during the patient's visit to a hospital for a respiratory infection. The patient's occupation for 26 years involved spraying PTFE. A lung biopsy using bronchoscopy revealed granulomatous lesions and giant cells. The presence of fluorine in the granulomatous lesions was confirmed using an electron probe microanalyzer with wavelength dispersive spectrometer. Fluorine is a component of PTFE and is not found in normal lung tissue.

Charge-carrier injection into pentacene thin film formed on Si(111) probed by STM spectroscopy.

The injection of charge carriers into a pentacene thin film formed on a Si substrate was investigated by scanning tunneling microscopy (STM). Tip height versus bias voltage (z-V) spectroscopy reveals the characteristic charge transport properties of the molecular film, i.e., the conductivity and the threshold energy of charge injection. The abrupt descent of the tip into the film owing to the transition of film conductance, which depends on the degree of charge carrier injection, was observed for crystallized pentacene thin films. The lower film conductance at around zero bias voltage is still higher than that of a vacuum. This indicates that the carrier injection barrier between the pentacene and the semiconducting substrate is extremely low. The convergence of the carrier injection endpoints into a narrow range of electric-field intensity implies that the main factor contributing to barrier formation and collapse is not the bias voltage but the electric field.

Tongue reconstruction with the gracilis myocutaneous free flap.

We describe our experience in tongue reconstruction using the transverse gracilis myocutaneous (TMG) free flap after major demolitive surgery for advanced cancer. This technique was used in 10 patients: seven underwent total glossectomy and three partial glossectomy. In eight patients we performed motor reinnervation attempting to maintain muscular trophism and gain long-term volumetric stability. The follow-up period ranged from 6 to 28 months. The overall flap survival was 100%. Nine out of 10 patients resumed oral intake. Our preliminary experience shows that this flap is a good reconstructive option for total glossectomy patients, whereas it is less suited for reconstruction of hemiglossectomy defects. Functional and objective evaluation of the tongue reconstructed with TMG free flap requires further and standardized evaluation.

Influence of residual bone on recombinant human bone morphogenetic protein-2-induced periodontal regeneration in experimental periodontitis in dogs.

BACKGROUND: Previous studies reported that bone morphogenetic protein (BMP)-2 induced periodontal regeneration in animals. However, the effects of local host factors on bone formation when using recombinant human (rh)BMP-2 are unknown. The purpose of this study was to evaluate local conditions in recipient sites that affected periodontal regeneration following BMP implantation in experimentally induced horizontal defects in dogs. METHODS: Experimental periodontitis was induced in the maxillary and mandibular premolars of six male beagles. The recipient sites were divided into four quadrants (maxillary buccal, maxillary palatal, mandibular buccal, and mandibular lingual sites). A polymer-coated gelatin sponge (PGS; 3 x 3 x 2 mm) was impregnated with 7.2 mul rhBMP-2 solution. The recipient sites in each quadrant were treated with physiologic saline/PGS and rhBMP-2/PGS (rhBMP-2 at 7.2 mug/7.2 mul). The dogs were sacrificed 12 weeks post-surgery, and healing was evaluated histologically. RESULTS: Bone formation and connective tissue attachment were observed following rhBMP-2/PGS implantation. In the four recipient sites of the BMP-treated group, significant positive correlations were found between the width of residual bone and the height and area of regenerated bone (r = 0.791; r = 0.828; P <0.0001). The height of regenerated bone was also significantly correlated to the area (r = 0.891; P <0.0001). CONCLUSIONS: The width of residual bone was one of the clinical host factors that affected bone regeneration following BMP implantation. However, it did not affect connective tissue attachment, cementum regeneration, and downgrowth of junctional epithelium.

Biocompatibility and permeability of dialyzer membranes do not affect anemia, erythropoietin dosage or mortality in japanese patients on chronic non-reuse hemodialysis: a prospective cohort study from the J-DOPPS II study.

BACKGROUND: Considerable controversy exists over the impact of the biocompatibility and flux characteristics of dialyzer membranes on anemia in chronic hemodialysis patients. METHODS: A subset of 1,207 subjects from the Japanese arm of DOPPS phase II was analyzed. RESULTS: Patient characteristics included mean age 59 years, male sex 60%, BMI 20.6, time on dialysis therapy 7.8 years, and diabetes rate 27%. Dialysis parameters were Kt/V 1.33, and normalized protein catabolic rate 1.05 g/kg/day. Initial hemoglobin level was 10.1 g/dl. 79% were treated by intravenous erythropoietin with mean weekly doses of 4,500 IU. Hemoglobin levels and erythropoietin doses during 2-year study period were not affected by dialysis membrane biocompatibility (unmodified cellulose or biocompatible) or flux (standard or high performance). The 2-year survival rate was 90.9% and was influenced by older age, presence of cardiovascular diseases and amyloidosis, lower levels of BMI and serum albumin, but not by other variables, including dialysis membranes. Use of biocompatible membranes was associated with a lower all-cause mortality (8.3 vs. 13.0% for bioincompatible, p = 0.037), but this difference was not significant in multivariate analyses (hazard ratio 0.70, p = 0.17 by Cox multivariate analysis). CONCLUSION: The biocompatibility and permeability of dialyzer membranes had no effect on anemia, erythropoietin dosage or all-cause mortality in Japanese chronic hemodialysis patients treated by non-reuse dialysis.

Evaluation of the sclerotherapeutic efficacy of ethanol, polidocanol, and OK-432 using an in vitro model.

BACKGROUND: Sclerosants are used to treat vascular malformations. Owing to variations in the flow, the injected concentrations and the duration of exposure of these sclerosants are altered. Therefore, the clinical effectiveness of sclerotherapy is variable. OBJECTIVE: The objective was to evaluate the differences in clinical response, usually observed among ethanol, polidocanol, and OK-432, using an in vitro sclerotherapy model. METHODS: Endothelial cells were cultured and exposed to different concentrations of the sclerosants for 5 seconds and the remaining viable cells were counted using a MTT assay kit. Dyes were used to visualize the morphologic changes. Precipitant formation in blood was also evaluated. Finally, the degree of ICAM-1 expression, after exposure to lower concentrations of these sclerosants, was studied using immunocytochemistry. RESULTS: Only ethanol causes precipitant formation and kills almost all cells from 30% concentration. Polidocanol begins to disrupt the cell membrane from 0.0125% onward. Only OK-432 induces ICAM-1 expression. CONCLUSION: Ethanol's strong precipitant-forming effect may induce thromboembolism, thus enhancing sclerosis. Polidocanol's endothelial cell-lysing effect was clearly documented. OK-432 may mediate its effect by inducing inflammatory response of the endothelium via ICAM-1 expression. This in vitro model may be useful in evaluating other sclerosants as well.

Circumstances, activities, and events precipitating aneurysmal subarachnoid hemorrhage.

Medical records of 513 patients with aneurysmal subarachnoid hemorrhage were reviewed to analyze the factors precipitating aneurysmal rupture. There was no seasonal difference in incidence. A significantly higher incidence was observed during 6:00 AM to 9:00 AM and 6:00 PM to 9:00 PM when engaging in daily routines such as defecation/micturition, brushing teeth/washing face/dressing, eating/drinking, and taking a bath. These activities are associated with a Valsalva maneuver that results in sudden pressure changes across the aneurysmal wall precipitating aneurysmal rupture. Aneurysmal rupture occurred most frequently during talking, chatting, watching television, or staying home without any strenuous physical activity. Considering the time spent, the highest incidence rate was found during defecation/micturition. There was no significant difference between men and women or between younger and older age groups regarding activities or events preceding aneurysmal rupture. Hypertension was the most common pre-existing medical problem. The main results are the same as those of the previous study except for aging of the patients.

Kinetic modelling of cytochrome c adsorption on SBA-15.

The adsorption capacity of mesoporous silicate (MPS) materials as an adsorbent for protein adsorption from the aqueous phase and the mechanism of the adsorption processes by comparative analyses of the applicability of five kinetic transfer models, pseudo-first-order model, pseudo-second-order model, Elovich kinetic model, Bangham's equation model, and intraparticle diffusion model, were investigated. A mixture of tetraethyl orthosilicate (TEOS) and triblock copolymer as a template was stirred, hydrothermally treated to form the mesoporous SBA-15 structure, and heat-treated at 550°C to form the MPS material, SBA-15. The synthesized SBA-15 was immersed in a phosphate buffered saline (PBS) solution containing cytochrome c for 2, 48, and 120 hours at 4°C. The TEM observations of proteins on/in mesoporous SBA-15 revealed the protein behaviors. The holes of the MPS materials were observed to overlap those of the stained proteins for the first 2 hours of immersion. The stained proteins were observed between primary particles and partly inside the mesoporous channels in the MPS material when it had been immersed for 48 hours. For MPS when it had been immersed for 120 hours, stained proteins were observed in almost all meso-scale channels of MPS. The time profiles for adsorption of proteins can be described well by Bangham's equation model and the intraparticle diffusion model. The Bangham's equation model is based on the assumption that pore diffusion was the only rate controlling step during adsorption, whose contribution to the overall mechanism of cytochrome c adsorption on SBA-15 should not be neglected. The kinetic curves obtained from the experiment for cytochrome c adsorption on SBA-15 could show the three steps: the initial rapid increase of the adsorbed amount of cytochrome c, the second gradual increase, and the final equilibrium stage. These three adsorption steps can be interpreted well by the multi-linearity of the intraparticle diffusion model, proving the significant role of intraparticle diffusion as one of the rate controlling mechanisms.

MicroRNA profiling in gingival crevicular fluid of periodontitis-a pilot study.

Periodontitis is a chronic inflammatory disease that affects the interface of teeth and surrounding tissues. Gingival crevicular fluid (GCF) is an exudate of the periodontal tissues and can be collected from the gap between the tooth and gum (gingival sulcus or periodontal pocket) with paper strips. Testing of GCF is a low-cost and minimally invasive procedure. In a variety of diseases, microRNAs (miRNAs) in body fluids are implicated in pathogenesis, and are suggested as potential diagnostic biomarkers. Here, we profiled miRNAs in GCF (two chronic periodontitis, one aggressive periodontitis, and five healthy subjects) using miRCURY LNA™ Universal RT microRNA PCR System, which yielded quantitative measures of more than 600 miRNAs. Through this analysis, we found that miRNA profiles in GCF of periodontitis patients are distinct from those of healthy controls. We further selected 40 miRNAs and confirmed their differential expression patterns in different subjects (five chronic periodontitis, one aggressive periodontitis, and six healthy subjects) using a custom miRNA PCR panel. This is the first demonstration of miRNA profiling in GCF and its alteration in periodontitis. Our findings suggest that a subset of miRNAs in GCF holds potential as a biomarker for periodontitis.

Asymmetrically functional surface properties on biocompatible phospholipid polymer membrane for bioartificial kidney.

To obtain a bioartificial kidney composed of a porous polymer membrane and renal cells, a polysulfone (PSf) membrane (PSM) blended with 2-methacryloyloxyethyl phosphorylcholine (MPC) polymer was prepared. The PSM flat membrane with a porous structure could be prepared from the polymer blend containing 1 wt % of the MPC polymer in PSf by the phase inversion technique in a dry-wet process. Asymmetrical surface properties were observed on both sides of the membrane surfaces. That is, the sponge layer formed at the substrate-contacting surface of the membrane had 10-20 microm pores, but the pores in the micrometer range could not be observed for a skin layer formed at the air-contacting surface of the membrane. At the sponge layer surface, the MPC unit composition was 7 times larger than that at the skin layer surface. The amount of proteins adsorbed on the surface corresponded to the MPC unit composition. On the skin layer, a small amount of adsorbed proteins and platelet adhesion could be suppressed compared with those on the sponge layer. However, the skin layer had a moderate protein adsorption, so it showed a sufficient cytocompatibility to enable renal tubule epithelial cells to adhere and proliferate in the membrane. Thus, it functioned well as a renal tubule. Therefore, because of both its hemocompatibility and cytocompatibility, we could conclude that the PSM membrane is useful for as a renal tubule device for a bioartificial kidney.

Present status and perspective of the development of a bioartificial kidney for chronic renal failure patients.

A bioartificial tubule device was applied for the treatment of 10 acute renal failure and multiple organ failure patients by Humes et al. A bioartificial kidney for chronic renal failure patients, however, has never been applied. In order to develop a bioartificial kidney for preventing and treating long-term complications of maintenance dialysis patients, we have to overcome difficulties such as antithrombogenic issue of hemofilters and development of long functioning tubule devices in the context of economical and easy treatment. Continuous hemofilters should modify with an antithrombogenic material on the inner surfaces of membranes to get more hemocompatible characteristics. We are developing an antithrombogenic continuous hemofilter coating with methacryloyloxyethyl phosphorylcholine polymer which will mimic phospholipid layers of human cell membrane on the inner surface of a hemofilter. The transportability of H2O, Na+, and glucose of bioartificial tubule devices using polysulfone hollow fiber modules and porcine proximal tubular epithelial cells LLC-PK1 were evaluated using two kinds of circuits of different medium inside and outside of the cell-attached hollow fiber membrane. Transport of H2O, Na+, and glucose were significantly increased when 2.5 g/dL of albumin was added, and plateaued on the eight day and then decreased thereafter until the 13th day. Transfection of a specific gene into human tubular epithelial cells might be required to keep contact inhibition in order to maintain a confluent monolayer for longer duration.

A Novel Regenerative Technique Combining Bone Morphogenetic Protein-2 With Fibroblast Growth Factor-2 for Circumferential Defects in Dog Incisors.

BACKGROUND: Periodontal regeneration of incisors is necessary for esthetic recovery. A novel regenerative method combining bone morphogenetic protein (BMP)-2 and fibroblast growth factor (FGF)-2 was developed. The purpose of this study is to evaluate periodontal healing, including root coverage, in circumferential defects of incisors. METHODS: Fifty incisors in five beagles were used. After circumferential defects were surgically created, each group, consisting of ten recipient sites, received: 1) a double layer with FGF-2 (2 µg)/collagen as inner layer and BMP-2 (4 µg)/collagen as outer layer (FB-DL group); 2) collagen impregnated with both FGF-2 (2 µg) and BMP-2 (4 µg) (FB-M group); 3) BMP-2 (4 µg)/collagen (B group); 4) FGF-2 (4 µg)/collagen (F group); or 5) collagen (C group). Dogs were sacrificed 8 weeks post-surgery, and healing was evaluated histologically. RESULTS: The three groups treated with BMP-2 showed enhanced new bone formation compared with control and F groups (P < 0.05). Furthermore, connective tissue attachment with cementum regeneration in the FB-DL group was significantly greater than in FB-M and B groups (P <0.05). Ankylosis in the FB-DL group was significantly less than in FB-M and B groups (P <0.05). Gingival recession was inhibited significantly better in FB-DL and FB-M groups compared with control and B groups. CONCLUSION: These data support development of a double-layer method combining BMP-2 and FGF-2 as a therapeutic approach to periodontal regeneration at incisors with horizontal circumferential defects.

A Prospective Multicenter Randomized Controlled Study on Interleukin-6 Removal and Induction by a new Hemodialyzer With Improved Biocompatibility in Hemodialysis Patients: A Pilot Study.

We compared interleukin-6 (IL-6) removal and induction between conventional polysulfone (Con) and TORAYLIGHT NV (NV) dialyzers in hemodialysis patients. Twenty patients on Con with high IL-6 concentrations (2.7-8.5 pg/mL) were randomized to Con or NV group. Dialyzer performance was determined in NV group while patients were on Con and after being switched onto NV. Erythropoiesis-stimulating agent (ESA) response index (ERI) was assessed every 4 months for one year. IL-6 clearance was comparable between Con and NV. IL-6 removal rates were comparable for the first 1 h, but were higher with NV for the entire session (P = 0.03). Before-to-during-dialysis IL-6 concentration ratios were lower with NV on the venous side after the session (P = 0.03). During the one-year study, hemoglobin was lower in Con group than in NV group at month 8 (P = 0.046). ERI decreased in NV and increased in Con group, with a significant difference between the groups (P = 0.002). NV and Con are comparable in removing IL-6 and both induce IL-6. However, the data suggest that NV induces less IL-6, which may reduce the risk of ESA hyporesponsiveness.

Transcriptome analysis of periodontitis-associated fibroblasts by CAGE sequencing identified DLX5 and RUNX2 long variant as novel regulators involved in periodontitis.

Periodontitis is affecting over half of the adult population, and represents a major public health problem. Previously, we isolated a subset of gingival fibroblasts (GFs) from periodontitis patients, designated as periodontitis-associated fibroblasts (PAFs), which were highly capable of collagen degradation. To elucidate their molecular profiles, GFs isolated form healthy and periodontitis-affected gingival tissues were analyzed by CAGE-seq and integrated with the FANTOM5 atlas. GFs from healthy gingival tissues displayed distinctive patterns of CAGE profiles as compared to fibroblasts from other organ sites and characterized by specific expression of developmentally important transcription factors such as BARX1, PAX9, LHX8, and DLX5. In addition, a novel long non-coding RNA associated with LHX8 was described. Furthermore, we identified DLX5 regulating expression of the long variant of RUNX2 transcript, which was specifically active in GFs but not in their periodontitis-affected counterparts. Knockdown of these factors in GFs resulted in altered expression of extracellular matrix (ECM) components. These results indicate activation of DLX5 and RUNX2 via its distal promoter represents a unique feature of GFs, and is important for ECM regulation. Down-regulation of these transcription factors in PAFs could be associated with their property to degrade collagen, which may impact on the process of periodontitis.

Evaluation of proliferation and functional differentiation of LLC-PK1 cells on porous polymer membranes for the development of a bioartificial renal tubule device.

To develop a bioartificial renal tubule system using renal tubular cells and porous polymer membrane hollow fibers, long-term maintenance of a confluent monolayer and the functionally differentiated condition of cells is essential. We examined the proliferation and functional differentiation of LLC-PK1 (Lewis-lung cancer porcine kidney 1) cells on two types of membranes: polysulfone and cellulose acetate. Cell proliferation was significantly higher on the polysulfone membrane than on the cellulose acetate membrane, and was enhanced by coating the membranes with various extracellular matrices. Confluent monolayer formation of cells was observed on matrix-coated polysulfone membrane but not on matrix-coated cellulose acetate membrane within 1 week. Cell proliferation continued for 3 weeks after confluent monolayer formation. Messenger RNA (mRNA) expression of glucose transporters, indicators of the functional differentiation of the LLC-PK1 cells, was observed in the polysulfone and cellulose acetate membrane groups, but was not observed in the nonporous polystyrene plate group under subconfluent conditions. Expression of glucose transporters mRNA was maintained for 3 weeks after confluent monolayer formation. Polysulfone membrane is more suitable than cellulose acetate membrane for a bioartificial renal tubule system with regard to LLC-PK1 cell proliferation. Extracellular matrix coating of the membrane further improves cell proliferation.

Favorable healing following space creation in rhBMP-2-induced periodontal regeneration of horizontal circumferential defects in dogs with experimental periodontitis.

BACKGROUND: Recombinant human bone morphogenetic protein-2 (rhBMP-2) is believed to be capable of inducing periodontal regeneration. However, the risk of aberrant healing events, such as root resorption and ankylosis, has been reported. We hypothesized that implantation of BMP-containing carriers directly on the root planed surface may be the cause of unfavorable healing. The purpose of this study was to evaluate the influence of a 1 mm spacer membrane, which separated the rhBMP-2 in polymer-coated gelatin sponge (PGS) and the root surface, on periodontal regeneration of experimentally induced horizontal defects in dogs. METHODS: Horizontal circumferential periodontal defects were surgically created, and experimental periodontitis was induced in 72 maxillary and mandibular premolars of four male beagle dogs. The recipient sites of each quadrant received: 1) rhBMP-2/PGS (B group) (rhBMP-2 at 1.0 mg/ml, total implant volume/ site approximately 7.2 microl) (n = 24); 2) rhBMP-2/PGS with a spacer membrane (PB group) (n = 24); and 3) physiological saline (PS)/PGS as a control (P group) (n = 24). One quadrant was left untreated. Dogs were sacrificed at 12 weeks post-surgery, and healing was evaluated histologically. RESULTS: Both groups treated with rhBMP-2/PGS demonstrated enhanced new bone formation and connective tissue attachment with cementum regeneration when compared to the control group. Sites treated with rhBMP-2/PGS showed a greater degree of bone formation than sites treated with rhBMP-2/PGS and spacer membrane, although the latter sites showed no ankylosis. CONCLUSIONS: Implantation of rhBMP-2/PGS enhances bone formation and connective tissue attachment in horizontal circumferential defects. In addition, the use of a spacer membrane reduces the degree of bone formation, but minimizes ankylosis.

Influence of root conditioning prior to EMD application on periodontal ligament cells of extracted teeth.

BACKGROUND: Root conditioning prior to the application of Enamel Matrix Derivative (EMD) on the root surface was suggested for treatment of replanted avulsed teeth. However, some studies do not support the use of root conditioning. The purpose of this study was to investigate the effects of root conditioning on cell proliferation and Alkaline Phosphatase (ALP) activity on application of EMD in vitro. METHODS: Thirty incisors of five beagle dogs were used. The roots were hemisectioned axially and the periodontal ligament and cementum were removed from the coronal half of the roots. The specimens were treated with or without root conditioning (24% EDTA for 2 minutes or 36% ortho-phosphoric acid for 60 seconds) and EMD were or was not applied. Then all specimens were observed using SEM or cultured for 4 weeks. After culture, the cell migration and alkaline phosphatase activity of migrated and proliferated cells on the root planed surface from the remaining periodontal ligament was histometrically observed. RESULTS: The cell population in EMD-applied groups was significantly higher than that without EMD application groups. There was no significant difference among the two root conditioning protocols and EMD alone. ALP activity of migrated and proliferated cells in the EMD in combination with EDTA group was significantly higher than the other groups. However, 36% ortho-phosphoric acid group showed the lowest value. CONCLUSION: The findings in this study showed that EMD in combination with 24% EDTA showed additional benefit in terms of population of cells expressed APL activity on the root surface compared with application of EMD alone.