Effectiveness of novel oral hygiene instruction avoiding inattentional blindness using an application for unique plaque control record calculation: A randomized clinical trial.

OBJECTIVE: This study was performed to estimate the effectiveness of novel oral hygiene instruction (OHI) focusing on areas with deep periodontal pockets for reduction of periodontal inflammation. BACKGROUND DATA DISCUSSING THE PRESENT STATUS OF THE FIELD: Because stained areas on the plaque chart do not always correspond to the areas with deep periodontal pockets, conventional OHI based on O'Leary's plaque control record (PCR) often provides guidance inconsistent with the target area. METHODS: This randomized clinical trial involved two groups: (1) OHI based on the PCR limited in deep pocket sites (novel OHI group) and (2) OHI based on O'Leary's PCR (conventional OHI group). The unique PCR (aggressive target for PCR [agPCR]; only counting the plaque-stained areas with PD at ≥4 mm sites) for the novel OHI was calculate by dedicated expression program. The probing depth (PD), bleeding on probing (BOP), and periodontal inflamed surface area (PISA) were obtained at the baseline and 5 to 6 months later. RESULTS: The approximation curve with PISA before and after instruction indicated that the PISA converged to a lower value after instruction in the novel OHI group. The approximation curve with the improvement rate of the PISA and agPCR showed a positive correlation in the novel OHI group but no correlation in the conventional OHI group. CONCLUSION: Control of inflammation was more effective in the novel OHI group. These results suggest that this novel OHI technique using our developed application could be used as a strategy to improve the effectiveness of brushing instruction.

Suppression of subgingival bacteria by antimicrobial photodynamic therapy using transgingival irradiation: A randomized clinical trial.

BACKGROUND: Antimicrobial photodynamic therapy (aPDT) is an effective method for eradicating bacteria in periodontal therapy. Standard aPDT requires the insertion of a laser tip into a periodontal pocket, in which the direction of irradiation is limited. Therefore, we devised an aPDT method that uses a transgingival near-infrared wavelength and indocyanine green-encapsulated and chitosan-coated nanoparticles as a photosensitizer. METHODS: Forty patients undergoing supportive periodontal therapy, who had a single root tooth with a pocket of 5 mm or deeper, were used as subjects. In the test group, aPDT was performed by laser irradiation from outside the gingiva using photosensitizer nanoparticles. In the control group, pseudo aPDT without photosensitizer was performed by transgingival irradiation. Subgingival plaque was sampled from inside the pocket before, immediately after, and 1 week after treatment, and evaluated by colony counting and real-time polymerase chain reaction. RESULTS: There were no significant differences in age, sex, periodontal pocket depth, and bleeding on probing between the test and control groups. Compared with the colony count before treatment, the count in the test group was significantly reduced immediately after treatment. The number of patients with colony reduction to ≤50% and ≤10% was significantly higher in the test group than in the control group. None of the participants reported pain, although one participant reported discomfort. CONCLUSION: As a bacterial control method for residual pockets in patients undergoing supportive periodontal therapy, transgingival aPDT is a promising treatment strategy that is not generally accompanied by pain or discomfort.

Ebi3 knockout aggravates experimental periodontitis via Th17 polarization.

AIM: To investigate the role of Ebi3-related cytokines (i.e., interleukin [IL]-35 and/or IL-27) in experimental periodontitis using Ebi3 knockout (KO) mice. MATERIALS AND METHODS: The maxillary right second molar teeth of Ebi3 KO mice and C57BL/6 mice were tied with a silk ligature to induce periodontitis. Three days after ligation, gingival tissues were collected for gene expression analyses. Five days after ligation, the maxillae were removed for haematoxylin and eosin staining and immunohistochemistry. Seven days after ligation, the maxillae were removed for micro-computed tomography. RESULTS: The ligated side of Ebi3 KO mice showed intense alveolar bone resorption, which was substantially more pronounced than in wild-type (WT) mice. IL-17A expression was significantly higher in the gingiva of the ligated side of Ebi3 KO mice compared with WT mice. IL-10 expression was significantly lower in Ebi3 KO mice than in WT mice. The ligature-induced alveolar bone resorption in Ebi3 KO mice that received recombinant IL-35 injection was significantly less compared with that in Ebi3 KO mice that received control injection. CONCLUSIONS: Together, these findings suggest that Th17 cells exacerbate experimental periodontitis in mice lacking Ebi3 and that IL-35 may play a critical role in inhibiting periodontal tissue destruction.

Porphyromonas gingivalis Fimbriae Induce Osteoclastogenesis via Toll-like Receptors in RAW264 Cells.

The effect of Mfa1 fimbriae of Porphyromonas gingivalis on the progression of bone resorption remains unclear, especially compared with another fimbriae, FimA. We investigated the effect of Mfa1 on osteoclastogenesis together with FimA. We also investigated the role of Toll-like receptors (TLRs) in Mfa1 recognition during osteoclast differentiation. Receptor activator of nuclear factor κß ligand (RANKL)-prestimulated RAW264 cells were used to examine the effects of purified Mfa1 fimbriae. The number of osteoclasts was examined by tartrate-resistant acid phosphate (TRAP) staining, osteoclast activation was investigated by bone resorption assays, and gene expression of differentiation markers was examined by quantitative real-time PCR. Transfection of Tlr2 and Tlr4 siRNAs into RAW264 cells was also employed and their role in Mfa1 recognition was investigated. Mfa1 effectively induced the formation of TRAP-positive multinucleated cells and activated osteoclasts. Mfa1 also increased gene expression of Acp5, Mmp9, and Ctsk in RANKL-prestimulated RAW264 cells compared with the control. The osteoclastogenesis induced by Mfa1 was significantly decreased in cells transfected with Tlr2 or Tlr4 siRNAs compared with control siRNA. Our results revealed the role of Mfa1 fimbriae in osteoclastogenesis that may contribute to the partial elucidation of the mechanisms of periodontal disease progression and the development of new therapeutic strategies.

Next-Generation Examination, Diagnosis, and Personalized Medicine in Periodontal Disease.

Periodontal disease, a major cause of tooth loss, is an infectious disease caused by bacteria with the additional aspect of being a noncommunicable disease closely related to lifestyle. Tissue destruction based on chronic inflammation is influenced by host and environmental factors. The treatment of periodontal disease varies according to the condition of each individual patient. Although guidelines provide standardized treatment, optimization is difficult because of the wide range of treatment options and variations in the ideas and skills of the treating practitioner. The new medical concepts of "precision medicine" and "personalized medicine" can provide more predictive treatment than conventional methods by stratifying patients in detail and prescribing treatment methods accordingly. This requires a new diagnostic system that integrates information on individual patient backgrounds (biomarkers, genetics, environment, and lifestyle) with conventional medical examination information. Currently, various biomarkers and other new examination indices are being investigated, and studies on periodontal disease-related genes and the complexity of oral bacteria are underway. This review discusses the possibilities and future challenges of precision periodontics and describes the new generation of laboratory methods and advanced periodontal disease treatment approaches as the basis for this new field.

Fabrication of Densified Rice Husk by Sequential Hot-Compressed Water Treatment, Blending with Poly(vinyl alcohol), and Hot Pressing.

Processing agricultural wastes into densified materials to partially substitute wooden product production is significant for reducing the consumption of forest resources. This work proposes the fabrication of high-strength rice husk (RH)-based composite materials with poly(vinyl alcohol) (PVA) via densification by hot pressing. RH was pretreated in hot-compressed water (HCW) prior to pulverization and blending with PVA or PVA/glycerol (GL). The incorporation of PVA greatly improved the strength, toughness, and waterproofness of the composite plate, which was discussed with the help of a variety of composite characterizations. The tensile strength, flexural strength, and toughness of a composite of HCW-treated RH, PVA, and GL with a mass ratio of 80:20:2 were 42, 81 MPa, and 5.9 MJ/m3, respectively. The HCW treatment and blending with PVA and GL improved those properties of the hot-pressed original RH plate by factors of 2.5, 2.3, and 6.7, respectively, and reduced the water uptake and swelling ratio in water by 57 and 53%, respectively, despite the hydrophilic nature of PVA and GL. Altogether, this work outlines a valuable and sustainable approach to the efficient utilization of agricultural wastes.

Catalytic deep eutectic solvent for levoglucosenone production by pyrolysis of cellulose.

This work presents the selective production of the versatile bio-based platform levoglucosenone (LGO) using deep eutectic solvents (DESs) as catalysts during cellulose pyrolysis. Among 18 types of DESs examined, those containing p-toluenesulfonic acid as a hydrogen bond donor possessed the requisite thermal stability for use in the pyrolysis of cellulose. When those DESs were combined with cellulose, the pyrolysis temperature could be reduced which led to greater selectivity for LGO, the highest yield being 41.5% on a carbon basis. Because of their thermal stability, the DESs could be recovered from the pyrolysis residue and reused. The DESs recovery reached 97.9% in the pyrolysis at a low temperature with the LGO yield of 14.0%. Thus, DES-assisted cellulose pyrolysis is a promising methodology for LGO production.

Porphyromonas gingivalis Components/Secretions Synergistically Enhance Pneumonia Caused by Streptococcus pneumoniae in Mice.

Streptococcus pneumoniae is an important causative organism of respiratory tract infections. Although periodontal bacteria have been shown to influence respiratory infections such as aspiration pneumonia, the synergistic effect of S. pneumoniae and Porphyromonas gingivalis, a periodontopathic bacterium, on pneumococcal infections is unclear. To investigate whether P. gingivalis accelerates pneumococcal infections, we tested the effects of inoculating P. gingivalis culture supernatant (PgSup) into S. pneumoniae-infected mice. Mice were intratracheally injected with S. pneumoniae and PgSup to induce pneumonia, and lung histopathological sections and the absolute number and frequency of neutrophils and macrophages in the lung were analyzed. Proinflammatory cytokine/chemokine expression was examined by qPCR and ELISA. Inflammatory cell infiltration was observed in S. pneumoniae-infected mice and S. pnemoniae and PgSup mixed-infected mice, and mixed-infected mice showed more pronounced inflammation in lung. The ratios of monocytes/macrophages and neutrophils were not significantly different between the lungs of S. pneumoniae-infected mice and those of mixed-infected mice. PgSup synergistically increased TNF-α expression/production and IL-17 production compared with S. pneumoniae infection alone. We demonstrated that PgSup enhanced inflammation in pneumonia caused by S. pneumoniae, suggesting that virulence factors produced by P. gingivalis are involved in the exacerbation of respiratory tract infections such as aspiration pneumonia.

Photodynamic Inactivation of an Endodontic Bacteria Using Diode Laser and Indocyanine Green-Loaded Nanosphere.

Apical periodontitis, an inflammatory lesion causing bone resorption around the apex of teeth, is treated by eradicating infectious bacteria from the root canal. However, it has a high recurrence rate and often requires retreatment. We investigated the bactericidal effect of antimicrobial photodynamic therapy (aPDT)/photodynamic antimicrobial chemotherapy (PACT) using indocyanine green (ICG)-loaded nanospheres coated with chitosan and a diode laser on a biofilm of Enterococcus faecalis, a pathogen of refractory apical periodontitis. Biofilm of E. faecalis was cultured in a porcine infected root canal model. ICG solution was injected into the root canal, which was then irradiated with a laser (810 nm wavelength) from outside the root canal. The bactericidal effect was evaluated by colony counts and scanning electron microscopy. The result of the colony counts showed a maximum 1.89 log reduction after irradiation at 2.1 W for 5 min. The temperature rise during aPDT/PACT was confirmed to be within a safe range. Furthermore, the light energy transmittance through the root was at a peak approximately 1 min after the start of irradiation, indicating that most of the ICG in the root canal was consumed. This study shows that aPDT/PACT can suppress E. faecalis in infected root canals with high efficiency.

Analysis of Primary Reactions in Biomass Oxidation with O2 in Hot-Compressed Alkaline Water.

The present study investigated oxidation of pulverized Japanese cedar with O2 in hot-compressed alkaline water, employing a newly developed flow-through fixed-bed reactor (percolator). It allowed us to determine the rate of the primary extraction that was free from the secondary reactions of extract in the aqueous phase and those over the residual solid, solubility of extractable matter, and mass transport processes. Quantitative kinetic analysis revealed that the cedar consisted of three kinetic components (C1-C3) that underwent extraction in parallel following first-order kinetics with different rate constants. Further analysis revealed the chemical compositions of the kinetic components, which were mixtures of carbohydrates and lignin. C1 was converted most rapidly by nonoxidative reactions such as alkali-catalyzed hydrolysis, while C2 was converted by oxidative degradation. The product distributions from C1 and C2 (CO2, lower organic acids, oligosaccharides, acid-soluble, and acid-insoluble lignins) were steady throughout their conversion. Both C1 and C2 thus behaved as single reactants; nevertheless, those were lignin/carbohydrates mixtures. It was also demonstrated that the extraction rate of C2 was proportional to the concentration of dissolved O2. C3 was the most refractory component, consisting mainly of glucan and very minimally of the lignin, xylan, mannan, galactan, and arabinan.

Gelatin Methacryloyl-Riboflavin (GelMA-RF) Hydrogels for Bone Regeneration.

Gelatin methacryloyl (GelMA) is a versatile biomaterial that has been used in various biomedical fields. UV light is commonly used to photocrosslink such materials; however, its use has raised several biosafety concerns. We investigated the mechanical and biological properties of a visible-wavelength (VW)-light-crosslinked gelatin-based hydrogel to evaluate its viability as a scaffold for bone regeneration in bone-destructive disease treatment. Irgacure2959 or riboflavin was added as a photoinitiator to create GelMA solutions. GelMA solutions were poured into a mold and exposed to either UV or VW light. KUSA-A1 cell-laden GelMA hydrogels were crosslinked and then cultured. Mechanical characterization revealed that the stiffness range of GelMA-RF hydrogel was suitable for osteoblast differentiation. KUSA-A1 cells encapsulated in GelMA hydrogels photopolymerized with VW light displayed significantly higher cell viability than cells encapsulated in hydrogels photopolymerized with UV light. We also show that the expression of osteogenesis-related genes at a late stage of osteoblast differentiation in osteoblasts encapsulated in GelMA-RF hydrogel was markedly increased under osteoblast differentiation-inducing conditions. The GelMA-RF hydrogel served as an excellent scaffold for the encapsulation of osteoblasts. GelMA-RF hydrogel-encapsulated osteoblasts have the potential not only to help regenerate bone mass but also to treat complex bone defects associated with bone-destructive diseases such as periodontitis.

Porphyromonas gingivalis Mfa1 Induces Chemokine and Cell Adhesion Molecules in Mouse Gingival Fibroblasts via Toll-Like Receptors.

Porphyromonas gingivalis Mfa1 fimbriae are thought to act as adhesion factors and to direct periodontal tissue destruction but their immunomodulatory actions are poorly understood. Here, we investigated the effect of Mfa1 stimulation on the immune and metabolic mechanisms of gingival fibroblasts from periodontal connective tissue. We also determined the role of Toll-like receptor (TLR) 2 and TLR4 in Mfa1 recognition. Mfa1 increased the expression of genes encoding chemokine (C-X-C motif) ligand (CXCL) 1, CXCL3, intercellular adhesion molecule (ICAM) 1 and Selectin endothelium (E) in gingival fibroblasts, but did not have a significant effect on genes that regulate metabolism. Mfa1-stimulated up-regulation of genes was significantly suppressed in Tlr4 siRNA-transfected cells compared with that in control siRNA-transfected cells, which indicates that recognition by TLR4 is essential for immunomodulation by Mfa1. Additionally, suppression of Tlr2 expression partially attenuated the stimulatory effect of Mfa1. Overall, these results help explain the involvement of P. gingivalis Mfa1 fimbriae in the progression of periodontal disease.

Deep Delignification of Woody Biomass by Repeated Mild Alkaline Treatments with Pressurized O2.

Delignification is essential in effective utilization of carbohydrates of lignocellulosic biomass. Characteristics of the delignification are important for the yield and property of the resulting carbohydrates. Oxidation with O2 of biomass in alkaline water can potentially produce high-purity cellulose at high yield. The present authors chose a Japanese cedar and investigated its oxidative delignification at 90 °C. The delignification selectivity was determined mainly by the chemical structures of lignin and cellulose. Treatment conditions, except for temperature, hardly changed the relationship between delignification rate and cellulose retention. During the treatment, dissolved lignin underwent chemical condensation in the aqueous phase. This "unfavorable" condensation consumed O2-derived active species, slowing down further delignification. Repeated short-time oxidation with renewal of alkaline water suppressed the condensation, enhancing the delignification. Repetition of 2-h treatments four times achieved 96% delignification, which was 8% higher than a single 8-h treatment at 130 °C.

IL-35 and RANKL Synergistically Induce Osteoclastogenesis in RAW264 Mouse Monocytic Cells.

Interleukin (IL)-35 is an immunosuppressive cytokine mainly produced by regulatory T cells. IL-35 mediates immunological functions by suppressing the inflammatory immune response. However, the role of IL-35 in bone-destructive diseases remains unclear, especially in terms of osteoclastogenesis. Therefore, the current study investigated the synergistic effect of IL-35 on osteoclastogenesis that is involved the pathogeneses of periodontitis and rheumatoid arthritis. Osteoclastic differentiation and osteoclastogenesis of RAW264 (RAW) cells induced by receptor activator of nuclear factor (NF)-κB ligand (RANKL) and IL-35 were evaluated by tartrate-resistant acid phosphate staining, hydroxyapatite resorption assays, and quantitative polymerase chain reaction. The effect of IL-35 on RANKL-stimulated signaling pathways was assessed by Western blot analysis. Costimulation of RAW cells by RANKL and IL-35 induced osteoclastogenesis significantly compared with stimulation by RANKL alone. Phosphorylations of extracellular signal-regulated kinase (ERK) and p38 mitogen-activated protein kinase tended to be increased by RANKL and IL-35 compared with RANKL or IL-35 alone. Additionally, the osteoclastogenesis induced by RANKL and IL-35 was suppressed by inhibition of ERK. In this study, IL-35 and RANKL induced osteoclastogenesis synergistically. Previous reports have shown that IL-35 suppresses the differentiation of osteoclasts. Therefore, IL-35 might play dual roles of destruction and protection in osteoclastogenesis.

Photochemical removal of acetaldehyde using 172 nm vacuum ultraviolet excimer lamp in N2 or air at atmospheric pressure.

The photochemical removal of acetaldehyde was studied in N2 or air (O2 1-20%) at atmospheric pressure using side-on and head-on types of 172 nm Xe2 excimer lamps. When CH3CHO was decomposed in N2 using the head-on lamp (HL), CH4, CO, and CO2 were observed as products in FTIR spectra. The initial removal rate of CH3CHO in N2 was ascertained as 0.37 min-1. In air (1-20% O2), HCHO, HCOOH, CO, and CO2 were observed as products in FTIR spectra. The removal rate of CH3CHO in air using the side-on lamp (SL) increased from 3.2 to 18.6 min-1 with decreasing O2 concentration from 20 to 1%. It also increased from 2.5 to 3.7 min-1 with increasing CH3CHO concentration from 150 to 1000 ppm at 20% O2. The best energy efficiency of the CH3CHO removal using the SL in a flow system was 2.8 g/kWh at 1% O2. Results show that the contribution of O(1D) and O3 is insignificant in the initial decomposition of CH3CHO. It was inferred that CH3CHO is initially decomposed by the O(3P) + CH3CHO reaction at 5-20% O2, whereas the contribution of direct vacuum ultraviolet (VUV) photolysis increases concomitantly with decreasing O2 pressure at < 5% O2. After initial decomposition of CH3CHO, it was oxidized further by reactions of O(3P), OH, and O3 with various intermediates such as HCHO, HCOOH, and CO, leading to CO2 as a final product.

Clinical Findings and Treatments of a Radially Deviated Type of Thumb Polydactyly.

BACKGROUND: Patients with some thumb polydactyly subtypes are regarded as having a high risk of secondary deformities or poor treatment outcomes. Radially deviated type is one of these subtypes, but its characteristics and definitive treatment outcomes remain unclear. This study aimed to evaluate the pre- and intraoperative findings and surgical outcomes of this subtype. METHODS: We identified eight patients with unilateral and proximal phalanx-type polydactyly. The mean age at surgery was 14.6 months, and the mean follow-up period was 7.2 years. We investigated the patients' initial radiograms, surgical procedures and findings, changes in alignment of the retained thumb, and postoperative outcomes using the Japanese Society for Surgery of the Hand scoring system. RESULTS: Although the gross appearance of the thumb was a radial deviation, there was an ulnar deviation at the metacarpophalangeal joint on radiography. The ulnar proximal phalanges were delta phalanges in three patients and were connected with the radial proximal phalanges by cartilage in five patients. We retained the ulnar thumbs in all patients and corrected the alignment in seven cases; open wedge osteotomy was performed for three patients with a delta phalanx, and tendon transfers from the radial to ulnar thumb were performed for the other four. The mean outcome score was 17.6/20, with one patient with excellent, six with good, one with fair, and none with poor scores. One patient experienced recurrent radial deviation around the interphalangeal joint five years after surgery and underwent corrective osteotomy, but the other patients maintained good alignment. CONCLUSIONS: Radially deviated thumb polydactyly is not simply radially deviated; the shape of the proximal phalanx of the ulnar thumb is important to determine the surgical procedure. However, our results indicated that the alignment is almost manageable, and the surgical outcome was comparable to that of patients with a proximal phalanx-type thumb polydactyly.

Efficient removal of benzene in air at atmospheric pressure using a side-on type 172 nm Xe2 excimer lamp.

The photochemical removal of benzene was studied in air at atmospheric pressure using a side-on type 172 nm Xe2 excimer lamp with a wide irradiation area. After 1.5 min photoirradiation, C6H6 (1000 ppm) in air was completely converted to HCOOH, CO, and CO2 at a total flow rate of 1000 mL/min. The initial decomposition rate of C6H6 was determined to be 1.18 min-1. By using a flow system, C6H6 (200 ppm) was completely removed at a total flow rate of 250 mL/min. The conversion of C6H6 and the energy efficiency in the removal of C6H6 changed in the 31-100% and 0.48-1.2 g/kWh range, respectively, depending on the flow rate, the O2 concentration, and the chamber volume. On the basis of kinetic model simulation, dominant reaction pathways were discussed. Results show that the O(3P) + C6H6 reaction plays a significant role in the initial stage of the C6H6 decomposition. Important experimental parameters required for further improvement of the C6H6 removal apparatus using a 172 excimer lamp were discussed based on model calculations.

Theoretical Study on Elementary Reaction Steps in Thermal Decomposition Processes of Syringol-Type Monolignol Compounds.

This paper theoretically investigated a large number of reaction pathways and kinetics to describe the vapor-phase pyrolytic behavior of several syringol-type monolignol compounds that are derived from the primary pyrolysis of lignin: 1-(4-hydroxy-3,5-dimethoxyphenyl)prop-2-en-1-one (HDPP), sinapyl alcohol, 3-hydroxy-1-(4-hydroxy-3,5-dimethoxyphenyl)propan-1-one (HHDPP), 1-(4-hydroxy-3,5-dimethoxyphenyl)propane-1,3-diol (HDPPD), and syringol. The possible pyrolytic pathways involving unimolecular decomposition, addition, and abstraction reactions were investigated by comparing the energy barriers calculated at the B3LYP/6-311++G(d,p) level. In the proposed pathways, all syringol-type monolignols containing a side chain undergo its cleavage to form syringol through the formation of syringaldehyde or 4-vinylsyringol. Syringol is then converted into two products: (a) pyrogallol via the homolysis of the O-CH3 bond and hydrogenation or (b) guaiacol via addition of an H atom with a carbon bearing methoxyl group in syrignol and the subsequent demethoxylation. The pyrolytic pathways of pyrogallol are classified into two processes: (a) the concerted dehydrogenation of the two hydroxyl H atoms and the unimolecular decomposition to produce acetylene (C2H2), ethynol (C2HOH), and CO or (b) the displacement of an OH with H to produce catechol and resorcinol. Additionally, HDPP undergoes O-CH3 bond cleavage to form but-1-en-3-yne. The high-pressure limit rate constants for all the proposed elementary reaction steps were evaluated on the basis of transition state theory.

Theoretical Study on the Kinetics of Thermal Decomposition of Guaiacol and Catechol.

The theoretical aspects of the development of a chemical kinetic model for guaiacol and catechol pyrolysis are presented to describe the pyrolysis behaviors of the individual lignin-derived components. The possible pyrolysis pathways involving both unimolecular and bimolecular decomposition were investigated by the potential energy surfaces (PES) calculated at CBS-QB3 level. The high-pressure limiting rate constants of each elementary reaction step were evaluated based on the transition state theory (TST) to determine the dominant pyrolysis pathways. The kinetic analysis results predicted the most favorable catechol unimolecular decomposition pathways, where catechol isomerization to 2-hydroxycyclohexa-2,4-dien-1-one occurred via migration of the hydroxyl H atom, followed by decomposition into 1,3-cyclobutadiene, acetylene, and CO. In the case of the bimolecular reaction of catechol, a hydrogen radical is coupled to the carbon atom in the benzene ring, leading to the formation of phenol and a hydroxyl radical through dehydroxylation. On the other hand, guaiacol is likely to form catechol and phenol via the O-CH3 homolysis and coupling of a hydrogen radical to the carbon atom with the methoxyl group, respectively.

Angiopoietin-like protein 2 regulates Porphyromonas gingivalis lipopolysaccharide-induced inflammatory response in human gingival epithelial cells.

Angiopoietin-like protein 2 (ANGPTL2) maintains tissue homeostasis by inducing inflammation and angiogenesis. It is produced in infiltrating immune cells or resident cells, such as adipocytes, vascular endothelial cells, and tumor cells. We hypothesized that ANGPTL2 might play an important role as a unique mediator in both systemic and periodontal disease. We demonstrated an increased ANGPTL2 concentration in gingival crevicular fluid from chronic periodontitis patients. Porphyromonas gingivalis lipopolysaccharide (LPS) treatment strongly induced ANGPTL2 mRNA and protein levels in Ca9-22 human gingival epithelial cells. Recombinant human ANGPTL2 increased interleukin 1ß (IL-1ß), IL-8, and tumor necrosis factor-α (TNF-α) mRNA and protein levels in Ca9-22 cells. Small-interfering (si)RNA-mediated ANGPTL2 knockdown in Ca9-22 cells reduced IL-1ß, IL-8 and TNF-α mRNA and protein levels compared with control siRNA (p<0.01) in P. gingivalis LPS-stimulated Ca9-22 cells. Antibodies against integrin α5ß1, an ANGPTL receptor, blocked induction of these inflammatory cytokines in P. gingivalis LPS-treated Ca9-22 cells, suggesting that secreted ANGPTL induces inflammatory cytokines in gingival epithelial cells via an autocrine loop. The classic sequential cascade of P. gingivalis LPS → inflammatory cytokine induction is well established. However, in the current study, we reveal a novel cascade comprising sequential P. gingivalis LPS → ANGPTL2 → integrin α5ß1 → inflammatory cytokine induction, which might be responsible for inducing potent periodontal disorganization activity in gingival epithelial cells. Via this pathway, ANGPTL2 functions in the pathogenesis of periodontitis and contributes to prolonging chronic inflammation in patients with systemic disease.