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string | predicted_class
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|---|---|---|
To probe the underlying biology associated with segmental AHO, biochemical and genetic studies were performed. Regions of high and low tracer accumulation could be isolated in mouse and probed by immunofluorescence . RT-PCR demonstrated increased versican (a large extracellular matrix proteoglycan) levels in low flow regions. Quantitative PCR arrays in enucleated human eyes demonstrated alterations in several extracellular matrix genes and their regulatory proteases . Using mouse models, segmental localization of fluorescent tracers in the TM of wild-type mice was abolished in the matricellular secreted protein acidic and rich in cysteine (SPARC) mutant . Distally, fluorescein microspheres could be seen past SC in the mouse as well .
|
study
| 100.0 |
Taken together, non-real time imaging techniques have emphasized the segmental nature of physiologic AHO and a potential relevance for treating ocular hypertension. Particularly exciting is the link of the segmental patterns to possible protein differences that might subserve the segmentalization. Note though that emphasis was on the TM here. Some of this was due to the use of larger particles. Larger particles allowed better maintained intraluminal presence without leakage so that tracers stayed within the AHO pathways during the processing time necessary for the non-real time assessment. However, larger particles may have also had a harder time passing through the TM easily. Thus, while clearly important for understanding AHO biology in model systems, non-real-time approaches using tagged beads or tracers may have a more limited clinical use in live human subjects and patient care.
|
review
| 98.5 |
Real-Time AHO imaging refers to visualizing tracer movement without the requirement to stop and process the tissue. The potential advantage here is that the variable of time between tracer introduction and tissue processing for non-real-time assessment is avoided. For the most part, real-time techniques have focused on small and clinically available tracers (fluorescein, indocyanine green (ICG), or trypan blue) using more clinical and surgical techniques. This is likely because clinical assessment of AHO in patient care would be better real-time since non-real-time methods rely so much upon pathological and histological methods.
|
review
| 99.75 |
Channelography and canalography are essentially the same technique that relies on unroofing Schlemm’s canal (SC) with introduction of the tracer (fluorescein, ICG, or trypan blue) [54–59]. The introduction can occur through local injection analogous to a viscocanulostomy surgery or through intermittent deposition from a flexible microcatheter as it is pulled through the eye during canaloplasty surgery. Such techniques have demonstrated images of AHO distinguishing ocular surface vessels associated with AHO from those that are not. While highlighting the anatomy, such approaches focus more on the potential space where aqueous humor can move. By introducing the tracer in SC, TM contributions are not considered. Also, no matter how quickly a surgeon pulls a flexible microcatheter out of the eyes 360 degrees around the limbus, it is impossible to deliver tracer simultaneously circumferentially to fairly assess segmental differences. Lastly whether the tracer is delivered at uniformly physiological pressures is unclear if the tracer is introduced while a microcatheter is actively being exited from the eye .
|
review
| 92.8 |
Searching for clear episcleral fluid waves represented another clever approach to identifying AHO pathways by looking for negative signal in the form of disappearance of blood in surface epislceral veins . Conducted with the irrigation function on commercially available phacoemulsification units during cataract surgery, by delivering a clear perfusate into the anterior chamber, local AHO pathways were determined by observing the flushing out of episcleral veins. The advantage is that this technique would be very familiar and comfortable to ophthalmic surgeons. Disadvantages are the need to look for loss of signal as opposed to positive signal and the high/supra-physiologic pressures used. Clinically, when studied retrospectively, a statistically significant correlation was seen between patients with extrinsic episcleral fluid waves and better surgical success with trabecular bypass .
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study
| 100.0 |
More recently, combining different aspects of the above approaches, aqueous angiography was a method that delivered fluorescent tracers into the anterior chamber with external imaging using an experimental microscopic setup or a clinically FDA-approved angiographic device (Heidelberg Spectralis HRA+OCT) (Figure 2). Using enucleated human and pig eyes, physiologic pressures were used, and introduction of the tracer into the anterior chamber allowed for simultaneous tracer delivery circumferential around the eye so that segmental changes could be fairly assessed. More importantly, delivery into the anterior chamber allowed outflow and angiographic results to be influenced by the TM.
|
review
| 99.44 |
Aqueous angiography was so termed to distinguish it from canalograms because the approach and information provided was different. This is analogous to the difference between classical congenital glaucoma surgeries: goniotomies and trabeculotomies . For aqueous angiography and goniotomies, ab-interno approaches were taken. Instead, canalography and trabeculotomies used ab-externo approaches. While goniotomies and trabeculotomies achieved the same result of TM destruction, aqueous angiography further differed from canalography in that aqueous angiography provided real-time AHO imaging that included influence from the TM.
|
review
| 99.6 |
This difference in information also parallels the techniques of percutaneous transhepatic cholangiography (PTC) and endoscopic retrograde cholangiopancreatography (ERCP) where, as the names imply, both can visualize the biliary system but ERCP provides easier images of the exocrine pancreatic ducts to detect pancreatic pathologies . Additionally, like canalograms and trabeculotomies, PTC could be considered ab-externo, as the tracer is introduced external through the surface skin inserting a needle into the gall bladder. ERCP, like aqueous angiography and goniotomies, takes an internal approach through the gastrointestinal lumen.
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other
| 99.75 |
Using enucleated pig and human eyes, aqueous angiography demonstrated segmental AHO patterns that mimicked non-real-time methods. Angiographic signal was validated as representing true AHO using anterior segment OCT and fluorescent dextrans studies . Angiographically positive but not negative regions demonstrated intrascleral lumens compatible with AHO on anterior segment OCT . With fluorescent dextrans, angiographically positive but not negative regions demonstrated trapping of the tracer in AHO pathways in the TM and angle . Quantitative methods have been developed to analyze these types of images .
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study
| 100.0 |
The meaning of any tracer study in any system is only as good as how close the tracer models the native substance of interest. The use of multiple tracers above with similar results of segmental AHO patterns in multiple species has been very reassuring. For AHO, aqueous humor is actually made up of many components . Predominately, aqueous humor is composed of water (molecular weight=18 g/mol). Small components such as ions are present. Other, less abundant components include small molecules (eg vitamin C…), to macromolecules (protein/DNA/RNA), to larger structures and cellular components. In a way, testing AHO with multiple tracers of different characteristics is the best way to model AHO. Larger tracers such microspheres [47–52] may reflect the larger component of aqueous. Given ICG’s propensity for protein binding, ICG aqueous angiography (Saraswathy S, et al. IOVS 2015; 56: ARVO Abstract 247) may mimic flow of proteins. Smaller tracers such as fluorescein better models small molecules and water . Putting these together a more comprehensive and realistic picture of aqueous outflow can be presented.
|
review
| 99.8 |
Clinically, aqueous humor outflow and its segmental nature may play a role in normal versus glaucomatous physiology and response to glaucoma therapy (medical or surgical). From a pharmacological standpoint, creating more uniform AHO may be beneficial .
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other
| 99.9 |
From a surgical standpoint, AHO imaging may help guide and customize MIGS in the individual patient for optimized IOP lowering. However, even with segmental aqueous angiographic information, a common clinical question is whether trabecular MIGS should be targeted to regions of greater flow to take advantage of known AHO pathways. The downside is that if flow is good, potential improvement there may be limited. Alternatively, should surgery be performed where flow is bad with the hopes of recruiting additional and increased AHO? This would be analogous to surgically improved AHO uniformity. The potential disadvantage is that maybe flow in initially poor regions may have been low because the anatomy didn’t support AHO in the first place. Now, tools for structural and functional assessment are available to ask these questions. Early experiments suggested that regions of initially poor flow could be recruited with TM bypass using a trabecular bypass stent (Huang AS, et al, 2016; AGS: paper presentation PA23).
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review
| 99.56 |
In patient care, combining many of the above techniques will be important. Ideally, clinical angiographic AHO assessment is real-time, includes contributions from the entire AHO pathways, allows for circumferential testing to fairly assess segmentalization and be conducted at physiologic pressures. For surgeries, real-world considerations must be had. While aqueous humor perfusion rigs have become ever sophisticated, patient safety, surgeon comfort, avoidance of unnecessary additional wounds, and time under anesthesia are factors. For example, most surgeons would not be willing to place a sharp needle in the sulcus space of a phakic patient to deliver the tracer there just because it is in a more physiologic starting point compared to the anterior chamber. Like the episcleral fluid wave approach, something familiar and comfortable to the ophthalmic surgeon will be important .
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other
| 99.9 |
In conclusion, for glaucoma, creating posterior segment structure: function relationships have been underway and are already quite developed [41–43]. In the anterior segment, a separate relationship is lacking and needs to be had. Modern tools, including anterior segment OCT and aqueous angiography, will likely play a role in creating that anterior segment structure: function understanding. Clinical relevance may come in the form of developing new pharmacological tools using structural or functional endpoints or improving surgical results from custom-targeted surgical approaches.
|
review
| 99.8 |
Periodontal disease is a chronic inflammatory infection affecting the gingiva, and is associated with gingiva, periodontal ligament, and alveolar bone loss1. The etiology of periodontal disease as a bacterial infection is well established. Several subgingival bacteria including Porphyromonas gingivalis (P. gingivalis), Prevotella intermedia, Tannerella forsythia, Aggregatibacter actinomycetemcomitans, and spirochetes are leading candidates as etiologic agents in periodontal disease2. Some form of periodontal disease affects 75% of the population; severe forms affect 14% of adults of all ages and 30% of older adults3. Direct treatment costs due to dental diseases including periodontal disease worldwide were estimated at US$298 billion yearly, corresponding to an average of 4.6% of global health expenditure billion yearly4. P. gingivalis is one of the main pathogenic factors of common periodontal disease in adults and is widely recognized as the black pigment producing anaerobic gram-negative bacteria involved in the initial progression of periodontal disease5–8. Furthermore, the burden that P. gingivalis infections place on the body may be larger than previous estimates, as periodontal disease is also associated with an increased risk of systematic symptoms, such as coronary heart disease and diabetes6, 9, 10.
|
review
| 99.9 |
The first antimicrobial substance to be discovered was penicillin, and this marked the beginning of the “golden age of antibiotics.” Recently, a severe lack of control in the use of antibiotics, great abuse in areas such as livestock feed, and unnecessary prescriptions for viral infections have led to growing global rates of antibiotic resistance in microorganisms. The discovery of new antibiotics cannot keep up with the speed of resistance developed by microorganisms. The rise in antibiotic resistance worldwide has driven research into the development of new antibacterial strategies. However, overall, 74.2% of the patients with chronic periodontitis have been revealed subgingival periodontal pathogens resistant to at least one of the test antibiotics. Additionally, some of the periodontitis bacteria forming red complex included P. gingivalis have been reported to acquire resistance to the antibiotic such as amoxicillin. Amoxicillin resistance was present in 43.3% of the study patient which β-lactamase enzymes capable of hydrolyzing β-lactam antibiotics11. Many antibiotics for periodontal disease treatment was not indicated to be associated with the interacellular energy metabolism inhibition of oral bacteria. Therefore, it is very important to intracellularly target molecules and/or microorgans not related to antibiotic resistance mechanisms. For example, antimicrobial photodynamic therapy (aPDT) has the potential to be an alternative to antibiotics, especially for the treatment of localized skin infections12.
|
review
| 99.9 |
The first use of the photodynamic activity of chemical compounds and visible light against microorganisms was published at the beginning of the last century. Hermann von Tappeiner et al. reported that the observed toxic effect in the presence of the light was not attributed to heat. In 1904, von Tappeiner coined the term “photodynamic reaction” for the reaction of light with a non-toxic dye13, 14. After a long hiatus, in the 1970’s photo dynamic therapy (PDT) began to be explored for the selective destruction of malignancies15. Common features of tumor cells and microorganisms are high proliferation and active metabolisms. Therefore, if microorganisms can accumulate different photosensitizers, photodynamic inactivation of them might be effective16.
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review
| 99.9 |
Even though the bactericidal properties of photodynamic effects have been known for a long time, only recently has there been increased interest in their practical use17–20. The development of resistance to aPDT appears to be unlikely because in microbial cells, reactive oxygen species (ROS), such as singlet oxygen (1O2) and some free radicals, interact with several cell structures and different metabolic pathways. Furthermore, aPDT is equally effective against antibiotic-resistant and antibiotic-susceptible bacteria, and repeated photosensitization has not induced the selection of resistant strains21, 22. There is also interest in applying aPDT against P. gingivalis, and studies have been conducted using visible light with wavelengths of 600 nm or more and with toluidine blue or methylene blue as a photosensitizer18, 23, 24. Visible light of 600 nm or greater is excellent for tissue penetration compared with shorter wavelengths due to low light absorption and scattering by living tissue25. Additionally, toluidine blue and methylene blue stain living tissues and cells as well as bacteria26–28. Therefore, these techniques using several stains may damage biological tissues and cells, even if it is effective as sterilization for P. gingivalis.
|
review
| 99.56 |
In this study, we focused on the dye porphyrin, which is the black pigment produced by P. gingivalis. First, we identified the excitation wavelength of porphyrin. Based on these results, we identified ROS induced by the photo-excited porphyrin in P. gingivalis and investigated the bactericidal effects from aPDT.
|
study
| 100.0 |
The fluorescence spectrum of the blue LED light is shown in Fig. 1A. Following photolysis, the Protoporphyrin IX (PpIX) spectrum has three peaks: 601.09, 635.77, and 703.76 nm, and the highest peak is at 703.76 nm (Fig. 1B).Figure 1(A) Relative spectral emission curve from LED and (B) relative spectral fluorescence of PpIX with blue light irradiation.
|
study
| 100.0 |
We investigated the ROS generated by PpIX upon blue light excitation. The characteristic ESR spectral pattern has three intense lines from the 2,2,6,6-tetramethyl-4-hydroxyl-piperidinyloxy (4-OH-TEMPO) radical, indicating that 1O2 generation was observed when using blue light to excite PpIX in the presence of 2,2,6,6-tetramethyl-4-piperidinol (4-OH-TEMP) (Fig. 2A). Even at high concentrations of PpIX, this generation of 1O2 was hardly observed without blue light irradiation. The spin concentration was about 5 µM with the 100J blue light irradiation of 100 µM PpIX (Fig. 2B). The spin concentration of products from 100 µM PpIX excited with 100J blue light was inhibited by the addition of L-histidine (Fig. 2C).Figure 2Singlet oxygen generation induced by PpIX upon blue light irradiation. (A) Typical in vitro ESR spectrum induced by PpIX upon blue light irradiation. (B) The concentration of generated singlet oxygen. (C) Generation of singlet oxygen with and without L-histidine at 100J of irradiation. The data are expressed as means ± SD (n = 3). Significant differences are expressed with * for p < 0.01 and † for p < 0.0001.
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study
| 100.0 |
Singlet oxygen generation induced by PpIX upon blue light irradiation. (A) Typical in vitro ESR spectrum induced by PpIX upon blue light irradiation. (B) The concentration of generated singlet oxygen. (C) Generation of singlet oxygen with and without L-histidine at 100J of irradiation. The data are expressed as means ± SD (n = 3). Significant differences are expressed with * for p < 0.01 and † for p < 0.0001.
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study
| 100.0 |
We examined the importance of PpIX in P. gingivalis and the fluorescence wavelength of PpIX. The P. gingivalis suspension of each optical density (OD) was measured at the fluorescence wavelength (excitation 460 nm and emission 703 nm) of PpIX. We performed statistics using Spearman’s rank correlation coefficient, and there was a strong correlation (r = 0.9727, p < 0.001) between the OD of P. gingivalis and the relative fluorescence intensity (Fig. 3A). We converted the relative fluorescence intensity of each P. gingivalis concentration into a quantity of PpIX. Figure 3B shows the results of linear regression analysis after using Spearman’s rank correlation coefficient to prove the significant correlation between P. gingivalis concentration and PpIX level.Figure 3PpIX quantity in P. gingivalis. (A) Correlation of the relative fluorescence units and P. gingivalis concentration change (n = 3). (B) Linear regression between the concentration of P. gingivalis and PpIX (n = 3). Dots represent the 95% confidence curve.
|
study
| 100.0 |
We investigated the effect of photodynamic therapy on P. gingivalis using blue light irradiation. As shown in Fig. 4, according to the logarithm of colony forming units (CFU) per mL, the viability of P. gingivalis was significantly suppressed in the 10J and 100J blue light irradiation groups compared with the non-irradiated (0J) group. However, no difference in survival was observed between the non-irradiated group and the 1J blue light irradiation group (Fig. 4).Figure 4Effect of blue light irradiation on the viability of P. gingivalis. The data are expressed as means ± SD (n = 3). Significant differences are expressed with * for p < 0.001 and as † for p < 0.0001.
|
study
| 100.0 |
We examined ROS generation induced by blue light irradiation in P. gingivalis. The P. gingivalis suspension containing 20 µM CellROX ® Green Reagent was irradiated with blue light. While ROS levels were significantly higher in the 100J blue light irradiation group compared with the non-irradiated (0J) group, there was no difference between the 0, 1, and 10J blue light irradiation groups (Fig. 5A). As shown in Fig. 5B, the oxidative stress levels of P. gingivalis DNA at 100J of blue light irradiation had significantly higher 8-OHdG levels compared with the non-irradiated (0J) group.Figure 5Oxidative stress induced by blue light irradiation of P. gingivalis. (A) ROS generation levels upon blue light irradiation in P. gingivalis. (n = 3) †Significant difference (p < 0.0001). (B) Generation of 8-OHdG upon blue light irradiation of P. gingivalis (n = 3) *Significant difference (p < 0.05).
|
study
| 100.0 |
Oxidative stress induced by blue light irradiation of P. gingivalis. (A) ROS generation levels upon blue light irradiation in P. gingivalis. (n = 3) †Significant difference (p < 0.0001). (B) Generation of 8-OHdG upon blue light irradiation of P. gingivalis (n = 3) *Significant difference (p < 0.05).
|
study
| 100.0 |
In recent years, because of the worldwide increase in antibiotic resistant bacteria, studies have been conducted on antimicrobial therapies using photodynamic therapy, which was already being used in cancer treatment29. Among the wide variety of bacteria in the oral cavity flora, the bacteria of periodontal disease are used for the study and application of aPDT in clinical practice. However, the current photodynamic therapy method is complicated, as it includes staining with a photosensitizer, and the bacterial sterilization mechanism has not been clarified18, 23, 24. In this study, we examined the sterilization mechanism of aPDT in bacterial cells using PpIX, a pigment used for energy production by P. gingivalis.
|
study
| 100.0 |
P. gingivalis requires iron and PpIX for growth30–32. The absorption spectrum of PpIX includes a maximal peak at 410 nm (Soret band) and four smaller peaks (Q-bands) from 500 to 630 nm33. Blue light at wavelengths of 400–500 nm is used for oral treatments such as resin restoration and tooth whitening34–36. The fluorescence wavelength peak (Fig. 1B) of PpIX excited with blue light (Fig. 1A) was consistent with the fluorescence wavelength for photodynamic diagnoses used in cancer therapy (600–740 nm)37, 38.
|
study
| 100.0 |
We attempted to detect ROS generated upon blue light irradiation of PpIX using an ESR technique used specifically for detecting ROS. Blue light irradiation of PpIX generates 1O2, a critical ROS (Fig. 2A,B). The inhibition of this ROS by typical scavenger L-histidine confirms it as 1O2 39, 40 (Fig. 2C). 1O2 is generated by photochemical reactions through the transfer of excitation energy from a suitable triplet state sensitizer or by radical interactions41. Furthermore, 1O2 is a powerful oxidizing molecule, and starts further oxidation reactions in closed environments such as bacterial cell walls, lipid membranes, enzymes, or nucleic acids42–44. 1O2 generated upon the blue light irradiation of PpIX increased in proportion to irradiation intensity (Fig. 2A,B).
|
study
| 100.0 |
We examined the presence of PpIX in P. gingivalis to investigate the possibility of 1O2 generation. The fluorescence intensity of P. gingivalis was measured using the excitation (460 nm) and emission (703 nm) wavelengths of PpIX, and the concentration of P. gingivalis and the relative fluorescence intensity increased proportionally, with a strong correlation (Fig. 3A). The observed correlation with the relative fluorescence intensity of P. gingivalis (Fig. 3B) suggested the presence of a photosensitizer like PpIX in P. gingivalis cells. Due to the presence of the photosensitizer-like pigment, we chose to investigate the effects of blue light irradiation on P. gingivalis. A decrease in the viability of P. gingivalis was observed with 10 and 100J of blue light irradiation (Fig. 4).
|
study
| 100.0 |
CellROX® Green Reagent is a cell-permeable reagent used to stain DNA that emits fluorescence in response to oxidative stress. This reagent can stain and be measured in Gram-negative bacteria such as Escherichia coli as well as in mammalian cells35, 45. The same irradiation protocol and viability measurements were performed with this reagent, and oxidative stress increased during 100J of irradiation (Fig. 5A). 8-OHdG is a constituent DNA base, deoxyguanosine (dG), hydroxylated at the C-8 position, and is a DNA oxidative damage marker. Since dG has the lowest redox potential of the four bases of DNA, it is susceptible to oxidation by ROS. For this reason, 8-OHdG, the major oxidation product of dG, sensitively reflects the impact of ROS on the organism46, 47. We evaluated 8-OHdG and observed significant enhancement in the 100J irradiation group in comparison with the 0J group (Fig. 5B). There was no effect of DNA oxidative damage with 10J blue light irradiation. We considered that the cell membrane was influenced the oxidative damage by low power irradiation. However, differences in lipid peroxidation, which is another possible way to evaluate oxidative stress in the cell membrane, was not detected (data not shown). Therefore, the mechanism is still unclear that ROS induced by 10J blue light irradiation suppressed CFUs. Nevertheless, 1O2 was generated by the intracellular pigment-like PpIX of P. gingivalis upon blue light irradiation, which then directly causes oxidative damage to DNA, inhibiting bacterial growth. Collectively, it was found that it might be possible to sterilize P. gingivalis using only the intracellular pigment-like PpIX and blue light irradiation (Fig. 6).Figure 6Blue light irradiation-induced antimicrobial mechanisms via protoporphyrin IX (PpIX) in Porphyromonas gingivalis.
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study
| 100.0 |
This approach is not a traditional aPDT approach, which is to use an exogenous photosensitizer such as toluidine or methylene blue to stain the bacteria. It is a simple method using a P. gingivalis-specific pigment. In addition, there is no possibility for the appearance of resistant bacteria in the future due to the photosensitizer being in the bacterium itself. Therefore, this method might be revolutionary and could change periodontal therapies using various other antimicrobial agents. However, phototoxicity is an issue that with enough evidence to cause uneasiness with this method, as blue light in itself brings about oxidation stress in oral tissues34. On the other hand, we have already studied blue light irradiation and cytotoxicity within the oral tissues, and determined that taking antioxidants such as N-acetyl-L-cysteine could defend against cytotoxicity, since the antioxidant is maintained in vascular circulation. The antioxidant remains in the blood circulation of the host body and provides the cells and tissues with protection while the oral bacteria remain susceptible with blue light irradiation34–36, 39. Therefore, the antioxidant effect of NAC is not applied to bacteria, applying the NAC might protect the host body tissue and be possible to directly damage a P. gingivalis bactericidal activity by blue light irradiation.
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study
| 100.0 |
In summary, our approach might be able to inspire new periodontal disease treatment only targeting the performance P. gingivalis, while taking into consideration the application of antioxidants before aPDT for protection of the oral tissues. In addition, aPDT using several exogenous dye has already been performed and clinical research results have been reported on periodontal disease treatment18, 23, 24. Unfortunately, this present study as aPDT which does not use exogenous dye, has not been carried out in vivo human study. We are going to need to implement in future dental aPDT treatment for the establishment of novel periodontal treatment.
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study
| 99.94 |
4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxide (TEMPOL), 4-OH-TEMP and PpIX disodium were purchased from Sigma-Aldrich (St. Louis, MO, USA). Phosphate buffered saline pH 7.2 (PBS) was purchased from the Invitrogen Corporation (Carlsbad, CA, USA), and L-histidine was purchased from Wako Pure Chemical Industries, Ltd. (Osaka, Japan). All other reagents were of analytical grade.
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other
| 99.94 |
Techno Light KTL-100 (Light emitting diode; LED), with a mounted light guide tip diameter of 4.3 mm and a blue transmission filter (225S-SPF500), were purchased from the Kenko Tokina Corporation (Tokyo, Japan). The LED output power was set to 400 mW/cm2 and wavelength to 460 nm using an optical power meter (8230E, ADC Corporation, Tokyo, Japan) before each experiment. P. gingivalis suspensions in each well were irradiated with the light source tip from the surface edge of the plate top at a depth of 10.9 mm for 96-well plates (Clear bottom black plate, Corning Incorporated, Corning, NY, USA) or 14.6 mm for 24-well plates (Clear bottom black plate, Eppendorf AG, Hamburg, Germany).
|
study
| 99.94 |
1O2 generated upon blue light irradiation of PpIX was analyzed quantitatively using ESR spectroscopy48, 49. It was detected by adding 1O2 trapping agent (100 mM 4-OH-TEMP) to PpIX solutions irradiated with blue light (460 nm, 400 mW/cm2). The concentration of the PpIX solution was 100 µM and blue light irradiation doses were 0, 1, 10, and 100J. We assessed the inhibitory effect of ROS in blue light irradiated PpIX solutions with 5 mM L-histidine34. We compared the double integrals of 4-OH-TEMP experimental spectra with those of a 10 μM TEMPOL standard measured under identical settings to estimate 1O2 adduct concentration50. ESR was performed using a JES-RE1X (JEOL, Tokyo, Japan) connected to a WIN-RAD ESR Data Analyzer (Radical Research, Tokyo, Japan) at the following instrument settings: microwave power, 8.00 mW; magnetic field, 335.8 ± 5.0 mT; field modulation width, 0.1 mT; sweep time, 1 min; and time constant, 0.03 s. All experiments were repeated three times.
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study
| 100.0 |
The bacterial strain used in this study was P. gingivalis ATCC 33277. P. gingivalis was grown in brain heart infusion broth (BHI broth; Difco Laboratories, Detroit, MI, USA) supplemented with 5 mg/ml yeast extract, 5 μg/ml hemin and 1 μg/ml vitamin K1 (BHIY-HK broth) for 18 h. P. gingivalis was also grown on BHI blood agar medium containing defibrinated 5% sheep blood at 37 °C for 5 days under anaerobic conditions (85% N2, 10% H2, 5% CO2). P. gingivalis was washed twice with PBS before each experiment to avoid the influence of medium pigments.
|
study
| 100.0 |
We adjusted each of the washed P. gingivalis suspensions to an optical density of 550 nm (OD550; 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, and 1.0) and then placed 150 μL per well into a 96-well plate. We measured the fluorescence of each well with infiniteM200 (Tecan Group Ltd., Männedorf, Switzerland) connected to PLATEmanagerV5 (Wako Pure Chemical Industries, Ltd, Osaka, Japan). The optimal excitation wavelength for detection was 460 nm and the emission wavelength was 703 nm.
|
study
| 100.0 |
The washed P. gingivalis suspensions were adjusted to an optical density of 0.6 at 550 nm and added to a 96-well plate at 150 µL per well, and then irradiated with 0, 1, 10, or 100J (1J; 400 mW/cm2, 2.5 sec. 10J; 400 mW/cm2, 25 sec. 100J; 400 mW/cm2, 250 sec). The survival of the P. gingivalis cells was estimated from viable bacteria by counting the number of CFUs 5 days after culture on BHI agar media under anaerobic conditions. The data is shown as the logarithm of CFU per milliliter.
|
study
| 100.0 |
The ROS production levels in blue light-irradiated P. gingivalis were measured with CellROX® Green Reagent (Promega Corporation, Madison, WI, USA). The washed P. gingivalis was adjusted to an optical density of 0.6 at 550 nm. P. gingivalis was suspended in PBS with 20 µM CellROX® Green Reagent and placed into a 96-well plate at 150 µL per well and irradiated for 0, 1, 10, or 100J. Non-target wells were covered with aluminum foil. After irradiation, the entire 96-well plate was covered with aluminum foil and incubated for 30 min at room temperature. The fluorescence intensity was measured with an infiniteM200 (Tecan Group Ltd., Männedorf, Switzerland) connected to PLATEmanagerV5 (Wako Pure Chemical Industries, Ltd., Osaka, Japan) at an excitation wavelength of 485 nm and an emission wavelength of 520 nm.
|
study
| 100.0 |
We also examined the oxidative stress on P. gingivalis DNA. The washed P. gingivalis was adjusted to an optical density of 0.6 at 550 nm and 1.5 mL per well was placed in a 24-well plate and irradiated at 0 or 100J. The precipitates obtained from collected samples after 2 min centrifugation at 12000 G were used for DNA extraction using ISOPLANT, according to the manual (Nippon Gene Co., LTD., Toyama, Japan). After measuring the DNA concentration with the NanoDrop ND-1000 spectrophotometer (NanoDrop Technologies, Inc., Wilmington, DE, USA) connected to NanoDrop 1000 Version 3.8.0 (Thermo Fisher Scientific, Inc., Waltham, MA USA), DNA was prepared with an 8-hydroxy-2′-deoxyguanosine (8-OHdG) Assay Preparation Reagent Set according to the manual (Wako Pure Chemical Industries, Ltd., Osaka, Japan). 8-OHdG was measured with a DNA/RNA Oxidative Damage ELISA kit, following the manufacturer’s instructions (Cayman Chemical Company, Ann Arbor, MI). After incubation for 90 min at room temperature, the absorbance was measured at 412 nm. The concentration of 8-OHdG was normalized to DNA concentration.
|
study
| 100.0 |
Data are represented by the mean ± standard deviation of minimum for the three separate experiments. All statistical analyses were performed with unpaired t-tests or Tukey’s multiple comparisons tests using GraphPad Prism 6 software (GraphPad Software Inc., La Jolla, CA, USA). A P-value of less than 0.05 was considered statistically significant.
|
study
| 99.8 |
One’s evaluation of the emotional value of objects appears to be influenced by ways in which an individual interacts with certain objects. For example, people tend to prefer objects that are repeatedly encountered relative to novel (i.e., unexposed) ones. This preferential bias has been labeled as the mere exposure effect (Zajonc, 1968). In addition to this heightening of preference, simply interacting with objects can also lead to a decrease in preference for certain objects (Raymond et al., 2003). In latter study, participants were presented with two different types of Mondrian-like stimuli and they were asked to select one of them as a target based on a specified categorical criterion. In a subsequent rating, participants were required to evaluate the affective valence of these two types of stimuli as well as of novel stimuli. The results showed that the stimuli previously rejected as distractors were subsequently evaluated more negatively than the stimuli selected as target and the novel stimuli. This emotional devaluation of the distractor stimuli, called the distractor devaluation effect (Raymond et al., 2003), is a robust phenomenon that has been observed in various experimental paradigms, such as in a visual search task (Fenske et al., 2004; Raymond et al., 2005), rapid serial visual presentation task (Kihara et al., 2011), and flanker task (Martiny-Huenger et al., 2014). In addition, this effect has been replicated using a wide range of stimuli such as geometric figures (Veling et al., 2008), line drawings (Griffiths and Mitchell, 2008), and human faces (Fenske et al., 2005).
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study
| 99.9 |
The widely accepted account of the distractor devaluation effect is based on attentional inhibition (Raymond et al., 2003; Fenske and Raymond, 2006; Raymond, 2009). In a typical study of the distractor devaluation effect, participants are asked to ignore distractor stimuli and to select target stimuli. In this situation, it appears that inhibitory processing is involved in the representation of the distractor stimuli, leading to the acquisition of a representational distractor code with an inhibitory status. This inhibitory status is activated and it is ultimately reflected in the subsequent preference rating of a distractor stimulus when it is next encountered. Three findings support this devaluation-by-inhibition account (Raymond, 2009). First, the distractor devaluation effect has been found in experimental paradigms that require participants to inhibit task-unrelated stimuli, such as the visual search (Raymond et al., 2005), negative priming (Goolsby et al., 2009a), and flanker tasks (Martiny-Huenger et al., 2014). Second, the magnitude of the distractor devaluation effect was proportional to the degree of the attentional inhibition, that is, greater attentional inhibition was required, hence more negative emotion was induced to the inhibited stimuli (Raymond et al., 2005). Third, the devaluation-by-inhibition account was also supported by an electrophysiological study (Kiss et al., 2007) as well by the aforementioned behavioral studies. These studies showed that the efficiency of the attentional selection of target stimuli, reflected in the timing of the N2pc component of event-related potentials, was associated with the negative evaluation of distractor stimuli (Kiss et al., 2007).
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study
| 94.6 |
In addition to the inhibition of attention, response inhibition required in the go/no-go or stop signal tasks also resulted in distractor devaluation (Fenske et al., 2005; Kiss et al., 2008; Veling et al., 2008; Buttaccio and Hahn, 2010; Doallo et al., 2012; Frischen et al., 2012; Wessel et al., 2014). In one of the studies (Kiss et al., 2008), participants were presented with a sequence of stimuli consisting of Asian and Caucasian faces. They were required to respond, by a key press, to the specified category of face (e.g., Asian face; go stimuli), whereas they were asked to refrain from responding to the other category of face (e.g., Caucasian face; no-go stimuli). In a subsequent rating task, participants had to rate the trustworthiness of the faces that had appeared in the preceding go/no-go task. Results indicated that the no-go stimuli were rated less trustworthy than the go-stimuli. The difference was attributed to the decreased trustworthiness for the no-go stimuli but not the increased trustworthiness for the go stimuli because the electrophysiological measure of response inhibition (i.e., nogo-N2) was associated with the negative evaluation of the no-go stimuli. The relationship between emotional devaluation and response inhibition was also confirmed in a neuroimaging study using functional magnetic resonance imaging (Doallo et al., 2012), which demonstrated that the activity in the lateral prefrontal cortex related to response suppression in the go/no-go task was involved in the distractor devaluation effect. However, as these two studies only compared go stimuli with no-go stimuli, they lacked a control condition (e.g., the presentation of unexposed stimuli). Further, several behavioral studies showed that no-go stimuli or stimuli presented with a no-go cue were devaluated when compared with stimuli in the control condition (Fenske et al., 2005; Veling et al., 2008). For example, following the go/no-go task where participants made a go/no-go response depending on the category of a letter superimposed on a picture, they rated the pictures associated with the no-go cue as less attractive than either novel pictures or pictures associated with the go cue (Veling et al., 2008).
|
review
| 99.2 |
Although it has been shown that both attention and response primarily affect the emotional devaluation of stimuli, it remains unclear whether there are interactions between attention and response controls. Specifically, it is unclear whether attention to stimuli has an influence on emotional devaluation based upon (i.e., through) the act of response inhibition. Several studies have demonstrated that stimuli previously presented with no-go cues (such as letter, digit, and colored circle) were devaluated as compared with novel stimuli or stimuli previously presented with go cues (Fenske et al., 2005; Veling et al., 2008; Buttaccio and Hahn, 2010). That is, these studies reported that response inhibition induced the emotional devaluation of unattended and task-irrelevant stimuli. However, to the best of our knowledge, few studies have directly compared the effect of response inhibition on attended (versus unattended) stimuli with respect to devaluations of emotions. In addition, in previous studies the presentation duration of the unattended stimuli was relatively long (about 1000 ms; Fenske et al., 2005; Buttaccio and Hahn, 2010). Therefore, it is possible that a participant’s attention was directed to task-irrelevant stimuli presented concurrently with no-go cues. In summary, it remains unclear whether attention facilitates emotional devaluation through response inhibition.
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study
| 99.56 |
Previous studies have suggested that attention plays an important role in the modulation of emotional evaluation. For example, the increase in positive affect toward repeatedly presented stimuli, called the mere exposure effect, is more likely to occur for attended stimuli than for unattended stimuli (Yagi et al., 2009; Huang and Hsieh, 2013). Furthermore, attention also plays an important role in evaluative conditioning where neural stimuli (conditioned stimuli), paired with affective stimuli (unconditioned stimuli), acquire the affective valence of the unconditioned stimuli. For example, distracting attention from conditioned and unconditioned stimuli disrupted the formation of conditioned affective valence (Field and Moore, 2012). In addition, distracting attention from the contingency between the conditioned and unconditioned stimuli also disrupted the effect (Kattner, 2012). Given that attention plays an important role in the acquisition of emotional value, emotional devaluation through response inhibition would occur more strongly for attended stimuli than it would for unattended stimuli.
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study
| 99.94 |
The aim of the present study was to investigate whether attention plays an important role in emotional devaluation through response inhibition. Accordingly, we conducted three experiments to clarify this issue. In Experiments 1 and 2, we examined the effect of response inhibition to attended pictures on their emotional devaluation. As in the previous studies, affective rating was preceded by a go/no-go task (Kiss et al., 2008; Doallo et al., 2012), where participants were asked to make a go or no-go response depending on the category of picture. Following the go/no-go task, participants were asked to report their preference for pictures that had appeared in the go/no-go task. Because the experimental procedure in Experiments 1 and 2 was similar to that of the previous studies (Kiss et al., 2008; Doallo et al., 2012), we predicted that emotional devaluation through response inhibition would occur. That is, the pictures that were previously presented as no-go stimuli would be evaluated less positively than the pictures that were presented as go stimuli. In Experiment 3, we examined the effect of response inhibition on the emotional devaluation of unattended stimuli concurrently presented with no-go cues. In contrast to Experiments 1 and 2, participants were asked to make a go or no-go response depending on the category of a digit target superimposed on the picture stimuli. Following the go/no-go task, participants were asked to rate their preference for the pictures that were (presumably) not attended to in the preceding go/no-go task. If attention plays an important role in the devaluation effect due to response inhibition, emotional devaluation would be attenuated in Experiment 3 compared with that in Experiments 1 and 2. In contrast, if attention is not necessary for emotional devaluation through response inhibition, comparable devaluation effects should be found in all experiments.
|
study
| 100.0 |
An additional important difference between the present and previous studies (Kiss et al., 2008; Doallo et al., 2012) was the inclusion of a control condition. Previous studies only compared the preference for the go stimuli with that for the no-go stimuli. Therefore, it was unclear whether the pictures presented in the go trials acquired positive valence or the pictures presented in the no-go trials acquired negative valence. One possible approach to clarify this is to include novel stimuli that were not presented in the go/no-go task. However, this might be inappropriate given that the distractor devaluation effect can occur in a category-based manner (Goolsby et al., 2009b). That is, it even occurs for novel stimuli belonging to a previously ignored category. Therefore, we did not include novel stimuli for a control condition. Instead, we asked participants to evaluate the preference for the pictures before and after the go/no-go task. This procedure would make it possible to disentangle the effect of response type on emotional devaluation through response inhibition.
|
study
| 100.0 |
The aim of Experiment 1 was to investigate the effect of response inhibition to attended pictures on the emotional evaluation of these pictures. To this end, participants were required to complete a go/no-go task, followed by a preference-rating task. In the go/no-go task, participants were asked to press space key when the picture of a specified target category was presented (i.e., a go trial) and to suppress the key response when the picture did not belong to the target category (i.e., a no-go trial). Previous studies have demonstrated that the pictures presented as no-go stimuli were rated less positively in subsequent rating than images presented as go stimuli (Kiss et al., 2008; Doallo et al., 2012). Thus, if attention plays an important role in emotional devaluation through response inhibition, we should obtain the same results as reported in the previous studies (Kiss et al., 2008; Doallo et al., 2012).
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study
| 100.0 |
All experiments (Experiments 1, 2, and 3) were approved by the Kwansei Gakuin University Institutional Review Board for Behavioral Research with Human Participants. In the three experiments, written informed consent was obtained from all participants, in accordance with the Declaration of Helsinki.
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other
| 99.94 |
All stimuli were presented on a 19-inch cathode-ray tube display at a resolution of 1280 × 1024 pixels, at a viewing distance of 52 cm. Stimulus presentation and response collection were controlled by a personal computer running of the Windows XP platform, and using Psychophysics Toolbox extensions (Brainard, 1997; Pelli, 1997) on Matlab (Mathworks Inc.).
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other
| 99.75 |
We used pictures of food (gummy candy and rice crackers) to extend the findings of the present study to the control of eating behavior through response inhibition (Houben and Jansen, 2011; Houben et al., 2011, 2012). Similar objects were used because the amount of inhibition necessary to withdraw responses plays an important role in the distractor devaluation effect (Frischen et al., 2012). Forty-five pictures for each category (gummy candy and rice crackers), recorded with a digital camera, were used in Experiment 1 (Figure 1). These pictures depicted different types of gummy candy and rice crackers. Five pictures for each category were used in practice trials; the remaining pictures were used in experimental trials. The pictures depicted a handful of gummy candies and rice crackers on a white paper dish. The width and height of each picture were 11.19 and 8.30°, respectively.
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study
| 100.0 |
The experiment began with a preliminary preference-rating task (Figure 2). In each trial, a picture of food was presented at the center of the display, along with a visual analog scale (VAS). The height and width of the VAS was 14.91 and 2.06°, respectively. The left end of the VAS indicated that the picture did not look delicious, whereas the right end of the VAS indicated that the picture looked delicious. Participants were asked to report their perceived deliciousness by clicking on a corresponding position on the VAS. The preference-rating task consisted of 10 practice trials (five trials for each food category) followed by 80 experimental trials (40 trials for each category). The presentation order of the pictures was completely randomized.
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study
| 100.0 |
Following the first preference rating, blocks of go/no-go trials and the second rating trials were administered; the go/no-go and rating blocks were alternately performed, as conducted in the previous studies (Kiss et al., 2008; Doallo et al., 2012). In each trial of the go/no-go task (Figure 1), a fixation circle was presented at the center of the display for 1200 ms, followed by the presentation of a picture for 300 ms (i.e., an inter-onset-interval between pictures of 1,500 ms). Participants were asked to press a space key as quickly and accurately as possible when the picture of a target category (gummy candy or rice crackers) was presented and to refrain from a key response when the picture of a non-target category was presented. Although picture duration was 300 ms, participants were allowed to respond during the 1,500 ms preceding the onset of the next picture. The next fixation circle and picture appeared regardless of whether the participant’s response was recorded. Each block of the go/no-go task consisted of 10 trials; 10 pictures, five for each stimulus category, were presented in a random order. The target category was instructed at the start of each block of trials and alternately changed from block to block. That is, in the half of the blocks the pictures of gummy candies were pared with a go response whereas in the remaining blocks the pictures of rice crackers were pared with a go response.
|
study
| 100.0 |
After completion of each go/no-go block of trials, a block of trials requiring preference ratings was presented. Pictures in this second rating task were identical to those in the preceding go/no-go block. The order of the pictures was also the same as that in the go/no-go block. After 10 practice trials for each go/no-go task and rating task, participants performed eight blocks of go/no-go trials and rating trials, respectively. Thus, each block of 10 go/no-go trials was followed by a block of 10 rating trials.
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study
| 99.94 |
We excluded the pictures to which the participants made incorrect responses in the go/no-go task from the analysis of preference rating. The mean proportion of excluded pictures was 0.07 (SE = 0.01). The responses obtained from the preference task were transformed so that the left end and right ends of the VAS were scored as 0 and 100, respectively. Mean preference rating was calculated in each condition, for each participant (Figure 5). An analysis of variance (ANOVA) was carried out on the mean preference ratings with rating phase (first vs. second) and stimulus category (go stimuli vs. no-go stimuli) as within-participant variables. The ANOVA showed significant main effects of rating phase, F(1,29) = 10.71, p < 0.01, ηp2 = 0.27, and stimulus category, F(1,29) = 6.93, p < 0.05, ηp2 = 0.19, which was qualified by the interaction between the rating phase and stimulus category, F(1,29) = 14.81, p < 0.01, ηp2 = 0.34. Post hoc simple effects showed that a significant increase in preference for go stimuli was found between the first and second ratings, F(1,29) = 16.38, p < 0.01, ηp2 = 0.36 whereas there was no significant difference in the preference for no-go stimuli between the first and second ratings, F(1,29) = 1.87, p = 0.18, ηp2 = 0.06. Importantly, in the second rating the preference for the no-go stimuli was lower than that for the go stimuli, F(1,29) = 14.76, p < 0.01, ηp2 = 0.34, which is consistent with the results reported in previous studies (Kiss et al., 2008; Doallo et al., 2012). According to the interpretation of these studies, these results suggest that the emotional devaluation of the no-go stimuli occurred through response inhibition (Kiss et al., 2008; Doallo et al., 2012).
|
study
| 100.0 |
Mean preference ratings for go and no-go stimuli as a function of rating phase in Experiment 1–3. White circles indicate the preference for go stimuli whereas black circles indicate the preference for no-go stimuli. Error bars show ± 1 SE. Asterisks indicate significant differences (∗p < 0.05, ∗∗p < 0.01).
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study
| 100.0 |
Although the response type in the go/no-go task influenced the subsequent preference rating, this effect reflected an increase for the go-stimuli but not a decrease for the no-go stimuli. This outcome appears to be contradictory to the view that emotional evaluation decreases due to response inhibition (Kiss et al., 2008; Doallo et al., 2012). One possible account for a lack of decrease in preference between the first and second ratings is insufficient task difficulty. A previous study found that the magnitude of emotional devaluation is correlated with the amount of inhibition necessary to withdraw responses (Frischen et al., 2012). From this fact, it is possible that emotional devaluation due to response inhibition did not emerge in Experiment 1 because, in this situation, the demand for response inhibition was relatively low because of the insufficient task difficulty. We therefore excluded this possibility in Experiment 2.
|
study
| 100.0 |
In Experiment 1, the mean preference rating for the no-go stimuli was comparable in the first and second ratings. One possible cause for the lack of the decrease in preference was that the go/no-go task in Experiment 1 was relatively easy; therefore, it is possible that participants did not need to suppress their response in the go/no-go task. In order to investigate this possibility, the task difficulty in the go/no-go task was increased in Experiment 2 relative to that in Experiment 1. A previous study demonstrated that the shortening of reaction time deadline (i.e., time window to respond) in the go/no-go task increased the task difficulty, which led to the increase in the inhibition necessary to withdraw responses (Benikos et al., 2013). Therefore, in Experiment 2, we used a shorter reaction time deadline to increase the task difficulty in the go/no-go task.
|
study
| 100.0 |
The stimuli and procedure were identical to those of Experiment 1, except that the duration of the fixation point in the go/no-go task was reduced to 900 ms, to increase the task difficulty. Consequently, the response time deadline was reduced from 1500 ms in Experiment 1 to 1200 ms in Experiment 2.
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study
| 99.94 |
Mean reaction time has been presented in Figure 3. In order to compare the reaction time in Experiment 2 with that in Experiment 1, a one-way ANOVA was conducted with experiments as a between-participant variable. The ANOVA showed that the mean reaction time was shorter in Experiment 2 than in Experiment 1, F(1,54) = 16.47, p < 0.01, ηp2 = 0.23, indicating that participants were urged to respond quickly by the reduction of the response time deadline. Mean hit and false alarm rates have been shown in Figure 4. In order to compare the task difficulty in Experiment 2 with that in Experiment 1, a one-way ANOVA was conducted on the hit rates with experiments as a between-participant variable. The ANOVA showed that the mean hit rate was lower in Experiment 2 than in Experiment 1, F(1,54) = 5.12, p = 0.03, ηp2 = 0.09. In contrast, the ANOVA conducted on the false alarm rates showed that the mean false alarm rate was higher in Experiment 2 than in Experiment 1, F(1,54) = 13.26, p < 0.01, ηp2 = 0.20. These results suggest that the reduction of the response time deadline in the go/no-go task increased the task difficulty in Experiment 2 compared with that in Experiment 1.
|
study
| 100.0 |
As in Experiment 1, we excluded the pictures presented in the error trials from the following analysis. The mean proportion of excluded pictures was 0.12 (SE = 0.01). The same ANOVA used in Experiment 1 was used to analyze data of Experiment 2. The resulting analysis revealed a significant main effect of rating phase, F(1,25) = 8.85, p < 0.01, ηp2 = 0.26, but a non-significant effect of stimulus category, F(1,25) = 2.43, p = 0.13, ηp2 = 0.09. As in Experiment 1, the interaction between rating phase and stimulus category was significant in the present experiment, F(1,25) = 13.38, p < 0.01, ηp2 = 0.35. Post hoc simple effects showed that the go stimuli were rated more positively in the second rating than in the first rating, F(1,25) = 16.02, p < 0.01, ηp2 = 0.39, whereas the preference for the no-go stimuli showed no differences between the first and second rating phases, F(1,25) = 2.29, p = 0.14, ηp2 = 0.08. Furthermore, in the second rating task, the no-go stimuli were rated more negatively than the go stimuli, F(1,25) = 7.86, p < 0.01, ηp2 = 0.21. These results clearly replicate the results of Experiment 1, suggesting that the response type in the go/no go task influenced the preference rating in the second rating phase. As in Experiment 1, mean preference ratings for the no-go stimuli did not differ between the no-go first and second rating phases. Thus, the lack of decrease in the preference for the no-go stimuli could not be attributed to the insufficient task difficulty in the go/no-go task because task difficulty in Experiment 2 was greater than that in Experiment 1.
|
study
| 100.0 |
To compare devaluation effects between Experiments 1 and 2, we calculated devaluation scores by subtracting the mean preference score for no-go stimuli in the second rating from that for go stimuli in the second rating for each participant. The means of the devaluation scores were 3.88 (SE = 1.01) in Experiment 1 and 3.57 (SE = 1.39) in Experiment 2. Then, these mean values were compared using a one way ANOVA, showing non-significant effect of experiments, F(1,54) = 0.03, p = 0.86, ηp2 = 0.00. That is, increasing the task difficulty did not affect the devaluation effect through response inhibition, which appears to be contradictory to the inhibitory account (Raymond et al., 2003; Fenske and Raymond, 2006; Raymond, 2009).
|
study
| 100.0 |
The results of Experiments 1 and 2 showed that the type of response influenced the preference for the pictures to which attention was directed in the preceding go/no-go task. Experiment 3 was designed to investigate whether the type of response also modulates the preference for unattended pictures in the preceding go/no-go task. In contrast to Experiments 1 and 2, in Experiment 3, participants were required to discriminate whether a digit superimposed on a picture was either odd or even. Because participant’s attention was focused on the target digit, it is plausible to consider that their attention is less directed to the pictures of gummy candies and rice crackers in the go/no-go task compared with that in Experiments 1 and 2. Thus, if attention plays an important role in emotional devaluation through response inhibition, the devaluation effect should be attenuated in Experiment 3 relative to that in Experiments 1 and 2.
|
study
| 100.0 |
The stimuli and the procedure were identical to those of Experiment 1, with the following exceptions. In the go/no-go task, the pictures of gummy candies and rice crackers were sequentially presented as in Experiment 1. However, a digit depicted on a white placeholder (0.39 and 0.77° in width and height, respectively) was superimposed on each picture (Figure 1). Odd numbers (1, 3, 5, 7, or 9) were presented in half of the trials in a block, whereas even numbers (0, 2, 4, 6, or 8) were presented in the other half of the trials in the block. In a half of the blocks, participants were required to press a space key when an odd number was presented, whereas they were required to refrain from the response when an even number was presented. In the other half of blocks, the assignment of the target category to the type of response was reversed. The target category was alternately changed from block to block and the order was counterbalanced across participants. The combination of the category of digits and the category of pictures was fixed for a participant. For example, one participant, only odd numbers (or only even numbers) were presented on the pictures of gummy candies (or only pictures of rice crackers). This combination was counterbalanced across participants.
|
study
| 100.0 |
Mean reaction time has been shown in Figure 3. In order to compare the reaction time in Experiment 3 with that in Experiment 1, a one-way ANOVA was conducted with experiments as a between-participant variable. However, the ANOVA did not reach significance, F(1,56) = 2.10, p = 0.15, ηp2 = 0.04. Mean hit and false alarm rates have been shown in Figure 4. In order to compare the task difficulty in Experiment 3 with that in Experiment 1, an ANOVA was conducted on the hit and false alarm rates, with experiments (Experiment 1 vs. Experiment 3) as a between-participant variable. The analysis revealed that the mean hit rate was higher in Experiment 3 than in Experiment 1, F(1,56) = 26.00, p < 0.01, ηp2 = 0.32, whereas the mean false alarm rate did not differ between experiments, F(1,56) = 0.25, p = 0.62, ηp2 = 0.004.
|
study
| 100.0 |
The difference observed between the experiments cannot be attributed to a difference in difficulty due to the timing of stimuli associated with reduced stimulus durations, because both stimulus durations and response time deadlines were identical in Experiments 1 and 3. Instead, this outcome is likely to reflect the difference in the discriminability of the target and distractor stimuli in these two experiments. In Experiment 1, several pictures of gummy candies (rice crackers) were considerably similar to the pictures in the other category; therefore, participants misidentified the pictures of one category as those of the other category. In contrast, the discrimination between even and odd numbers was relatively easy, as indicated by the higher hit rate in Experiment 3 than that in Experiment 2. From this, and from the absence of differences in the false alarm rates and the mean reaction times, it is plausible to consider that the demand for response inhibition in Experiment 3 was not much different from that in Experiment 1.
|
study
| 100.0 |
As in Experiment 1, we excluded the pictures presented in the error trials from the following analysis. The mean proportion of the excluded pictures was 0.03 (SE = 0.01). Mean preference ratings have been shown in Figure 5. The same ANOVA as in Experiment 1 was conducted on the preference ratings of Experiment 3. The ANOVA showed a significant main effect of rating phase (first vs. second), F(1,27) = 8.16, p < 0.001, ηp2 = 0.23, indicating that the mean preference score was higher in the second rating phase than that in the first rating phase. This effect probably reflects the mere exposure effect (Zajonc, 1968). In contrast to Experiment 1, there was neither main effect of stimulus category, F(1,27) = 0.21, p = 0.65, ηp2 = 0.008, nor an interaction between rating phase and stimulus category, F(1,27) = 0.06, p = 0.81, ηp2 = 0.002, indicating that emotional devaluation through response inhibition was not evident in Experiment 3. These results suggest that, in Experiment 3, the type of response in the go/no-go task did not affect the preference rating for the picture that had not been attended in the go/no-go task.
|
study
| 100.0 |
To ascertain the importance of attention in the devaluation effect through response inhibition, we compared the mean devaluation scores between Experiments 1 and 3 using a one-way ANOVA with experiments as a between-participants variable, which indicated that the mean devaluation score was greater in Experiment 1 (M = 3.88, SE = 1.01) than that in Experiment 3 (M = 0.41, SE = 0.84), F(1,56) = 6.86, p = 0.01, ηp2 = 0.11. This result suggests that attention to the stimuli in the go/no-go task facilitate emotional devaluation through response inhibition.
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study
| 100.0 |
The aim of the present study was to investigate whether attention plays an important role in emotional devaluation through response inhibition. In addition, another aim was to clarify whether the devaluation through response inhibition reflected a decreased preference for no-go stimuli or an increased preference for go stimuli. To this end, we assessed the effect of response inhibition in a go/no-go task on subsequent rating of preference for the pictures presented. In Experiment 1, participants made a go or no-go response depending on the category of picture stimuli, which was preceded and followed by a preference rating task for the picture presented in the go/no-go task. The results showed that, in the second rating, no-go stimuli (i.e., previously rejected stimuli) were rated less positively than go-stimuli (i.e., previously accepted stimuli). This finding is consistent with those of previous studies that demonstrated that response inhibition results in the emotional devaluation of the no-go stimuli (Kiss et al., 2008; Doallo et al., 2012). The results of Experiment 1 were replicated in Experiment 2, where the task difficulty of the go/no-go task was increased by reducing the reaction time deadline. In contrast to Experiments 1 and 2, Experiment 3 revealed that such a decrease from response inhibition was not obtained when the participants made a go/no-go response depending on the category of a digit superimposed on a depiction of the stimulus. In summary, we found that different ratings between the go and no-go stimuli occurred only when the participants attended to the picture stimuli in the go/no-go task.
|
study
| 100.0 |
Although an apparent devaluation effect occurred when participant’s attention was directed to the picture stimuli, this devaluation effect really reflected an increased preference for the go stimuli and not a decreased preference for the no-go stimuli. That is, we found no real devaluation effect through response inhibition, which is inconsistent with previous studies suggesting that response inhibition results in the devaluation of no-go stimuli (Kiss et al., 2008; Doallo et al., 2012). Note that these studies used a similar procedure as that in the present study but they lacked a control condition. They only compared the go stimuli with the no-go stimuli following a go/no-go task. Therefore, it is plausible that the valuation of the go stimuli but not the devaluation of the no-go stimuli occurs when the blocks of go/no-go trials and rating trials are conducted alternately, as in this and previous studies (Kiss et al., 2008; Doallo et al., 2012). We do not suggest that devaluation through response inhibition does not occur in any situation (Veling et al., 2008). However, it is suggested that in certain situations different ratings between go and no-go stimuli might be attributed to the increased preference for attended go stimuli.
|
study
| 100.0 |
One may think that insufficient task difficulty in the go/no-go task explains the lack of the difference in preference for the no-go stimuli between the first and second ratings. More specifically, the demand for inhibitory control might not be sufficient if the go/no-go task is relatively easy for participants. However, in Experiment 2, participants’ preference for the no-go stimuli did not differ between the first and second ratings, despite the fact that task difficulty in the go/no-go task was greater than that in Experiment 1. In addition, false alarm rate, which is one of the indexes of task difficulty, was equivalent or higher in the present study than were those reported in previous studies that have demonstrated emotional devaluation due to response inhibition (Kiss et al., 2008; Doallo et al., 2012). Therefore, the results of Experiments 1 and 2 suggest that the lack of the difference in preference for the no-go stimuli between the first and second rating could not be attributed to the insufficient task difficulty in the go/no-go task.
|
study
| 100.0 |
Why did the preference for go stimuli increase from the first to second ratings when the participants attended to the picture stimuli in the go/no-go task? One possible explanation, which is contrary to the inhibitory account (Kiss et al., 2008; Doallo et al., 2012) is that preference ratings are affected by the execution, but not by the inhibition of a response. In fact, a recent study reported that items previously presented with a tone were more often selected as more preferable than items presented without the tone when participants were required to respond to the tone. However, this selection bias was not observed when participants were required to inhibit responses on hearing the tone (Schonberg et al., 2014). Assuming that go responses are viewed as approaching responses to go stimuli, it is possible that the stimuli paired with the go response acquired positive valence, as reported in a previous study indicating that stimuli paired with an approaching response acquired positive valence (Cacioppo et al., 1993). Consistent with this account, the preference for the go stimuli increased from the first to second ratings. According to this explanation, the lack of differences in the second preference rating (Experiment 3 in the present study) might indicate the importance of attention in associating the execution of the response with the stimuli presented at the response, which is similar to the importance of attention in the association between multiple stimuli (Field and Moore, 2012; Kattner, 2012). In addition, this account might be consistent with the result that increased effort to inhibit responses did not affect preference ratings (Experiment 2 in the present study).
|
study
| 100.0 |
Another possibility is that increased preference for go stimuli could be attributed to the attentional modulation of the mere exposure effect. Previous studies have shown that attention to stimuli facilitate the mere exposure effect to those stimuli (Yagi et al., 2009; Huang and Hsieh, 2013). Given this finding and the increased preference for go stimuli, it could be inferred that participant’s attention was directed toward the go stimuli for a longer duration than to the no-go stimuli because of the additional time required to respond to the go stimuli, which might have resulted in the increased preference for the go stimuli. Consistent with this possibility, the increased preference from the first to second ratings was comparable between the go and no-go stimuli when participant’s attention was distracted from the pictures themselves (Experiment 3). The present study was not designed to determine if attention, or response execution played a critical role in the increased preference for the go stimuli. Nevertheless, an important implication of the present study is that devaluation through response inhibition does not occur under certain situations.
|
study
| 100.0 |
Finally, the results of the present study cautions us regarding the concept of devaluation due to response inhibition and its application to problems such as eating disorders. For example, recent studies have shown that response inhibition results in decreased food consumption (Houben and Jansen, 2011; Houben et al., 2011, 2012). For example, the consumption of chocolates was reduced after participants suppressed a key response when a picture of chocolates was presented under the no-go stimulus (Houben and Jansen, 2011). In addition, response inhibition also reduced the consumption of beer (Houben et al., 2011, 2012). Contrary to the explanation of these results presented in previous studies, the present study demonstrated that response execution and not response inhibition increased the preference for a stimulus. Therefore, it is possible that under certain situations, response execution increases the consumption of suitable foods. Further studies are needed to clarify the exact conditions under which response inhibition results in the emotional devaluation of no-go stimuli.
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study
| 99.94 |
The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The reviewer EDR and handling Editor declared their shared affiliation, and the handling Editor states that the process nevertheless met the standards of a fair and objective review.
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other
| 99.94 |
The oral cavity is a suitable milieu for bacterial growth and propagation. The presence of bacteria in the mouth readily stimulates the formation of dental plaque, which accumulates on both hard and soft tissues as dental calculus. Although the regional colonization and invasion of bacteria are rigorously controlled by the dynamic equilibrium between dental plaque bacteria (DPB) and the host’s innate defense mechanisms , plaque that extends subgingivally can trigger the immune system imbalance, inducing an inflammatory response . Gingivitis and periodontitis are the most common plaque-induced inflammatory conditions. Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, and Tannerella forsythensis are the most prevalent anaerobic gram-negative bacteria in subgingival area. All are critical in the onset and subsequent development of periodontitis. If untreated, these bacteria can lead to the periodontal pocket, connective tissue destruction, and alveolar bone resorption .
|
review
| 99.8 |
Bacteria involved in the initiation and progression of periodontal disease are classified into color-coded groups. The categories are based upon the pathogenicity of the bacteria and their role in the development of plaque . Species in the red complex (P. gingivalis, T. forsythia, and Treponema denticola) are strongly related with pocket depth and bleeding on probing. The red complex can be used as a clinical parameters that is considered the most meaningful in periodontal diagnosis. Species in the orange complex (Fusobacterium nucleatum, P. intermedia, Prevotella nigrescens, Peptostreptococcus micros, Streptococcus constellatus, Eubacterium nodatum, and Campylobacter gracilis) are closely associated with one another. The orange complex is closely related to the red complex. Similarly to the red complex, the orange complex is significantly associated with increasing pocket depth; a decreased level of these species lead to improvement in periodontal status. A. actinomycetemcomitans, which is classified in the green complex, is associated with localized aggressive periodontitis.
|
review
| 99.9 |
Toxins produced by DPB, such as lipopolysaccharide (LPS), stimulate an inflammatory response. LPS induces the release of various inflammatory mediators from gingival tissue, which activates the innate immune system of the host to eliminate the inflammation . Although such mediators are normally part of a beneficial host response to suppress bacterial proliferation, they can also damage the area of inflammation. During the inflammatory-immune response in gingivitis and periodontitis, inflammatory cytokines and matrix metalloproteinases (MMPs) are produced, which destroy the extracellular matrix (ECM) and lead to periodontal bone loss . In periodontal disease, the irreversible breakdown of collagen fibers in the periodontal ligament results in tissue destruction.
|
study
| 99.94 |
Epidemiological studies have consistently revealed the increase risk for periodontal disease with age. The National Health and Nutrition Examination Survey (NHANES) recently estimated that in the United States 47.2% of adults 30 years of age and older have periodontitis , and the prevalence of periodontitis among all adults increases with increasing age. The fact that over the past 2 years the risk of periodontitis has increased approximately 53.0% indicates the need for more intensive oral hygiene and dental care, and the dissemination of information regarding the treatment and prevention of periodontal disease .
|
review
| 97.6 |
The properties of various extracts of the fruit of the Terminalia chebula tree have been widely investigated and include anti-diabetic, anti-mutagenic, anti-oxidant, anti-bacterial, anti-fungal, and anti-viral effects . Many of these beneficial effects are related to the presence of various phytochemicals including polyphenols, terpenes, anthocyanins, flavonoids, alkaloids, and glycosides . In the present study, we determined the effects of an ethanol extract of T. chebula (EETC) in preventing DPB-induced inflammation and bone resorption, and identified the principal molecules in this inflammatory response that are regulated by EETC. The data indicate the potential value of EETC in preventing DPB-mediated periodontal disease.
|
study
| 99.94 |
Minimum essential medium alpha medium (α-MEM), RPMI 1640 medium, Dulbecco’s modified Eagle’s medium (DMEM)/F-12 phenol red-free medium (1:1), fetal bovine serum (FBS), antibiotic-antimycotic mixture (100×), phosphate-buffered saline (PBS), and 0.25% trypsin-EDTA (1×) were purchased from Gibco BRL Co. (Grand Island, NY). Dimethyl sulfoxide (DMSO), LPS, and 3-(4,5 dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) were obtained from Sigma-Aldrich (St Louis, MO). Recombinant mouse soluble RANK ligand (sRANKL) was purchased from Koma Biotech (Seoul, Republic of Korea). Recombinant mouse macrophage colony-stimulating factor (M-CSF) was purchased from R&D System (Minneapolis, MN). EETC was provided by COSMAX Inc. R&I Center (Seongnam City, Republic of Korea).
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other
| 99.9 |
T. chebula fruit were thoroughly washed with distilled water to remove dirt and soil, and dried under shade and ventilation. The dried fruits were ground using an electronic miller. The powder was extracted using 70% ethanol for 72 h at room temperature, filtered through Whatman filter paper No. 1, and concentrated using a rotary evaporator under reduced pressure. The dried extracts were stored in a refrigerator until for further use. Stock solution was aliquoted and stored frozen at −70 °C for up to 6 months. Freeze/thaw cycles were avoided.
|
study
| 99.5 |
Streptococcus mutans, Aggregatibacter actinomycetemcomitans, and DPB were cultured in brain-heart infusion (BHI) broth (Becton, Dickinson and Company, Baltimore, MD) at 37 °C with shaking at 200 rpm. Dental plaques were obtained through regular scaling from a participant without any oral mucosal disease and all procedures were performed by dental hygienist. Informed consent was given by the participant. Cells were harvested and PBS-washed three times by centrifugation at 3,000 rpm for 5 min. The washed cells were suspended in PBS and absorbance was measured at 600 nm using a DU 800 spectrophotometer (Beckman Coulter, Palo Alto, CA). A standard curves was generated for each bacterial sample and colony forming units (CFU)/ml was determined. For experiments requiring plate cultures, a bacterial suspension was subcultured onto the surface of BHI agar and bacterial growth was assessed. To stimulate the cultured cells, a multiplicity of infection (MOI) of 200 bacteria was applied for 24 h at 37 °C and 5% CO2.
|
study
| 100.0 |
MICs were determined for the EETC by the broth dilution method after incubation at 37 °C for 24 h under 5% CO2, with each determination done in triplicate. A MIC was the lowest concentration of test sample that completely inhibited visible growth in the broth.
|
study
| 99.94 |
LPS was extracted using a LPS extraction kit (iNtRON Biotechnology, Seongnam City, Republic of Korea) according to the manufacturer’s protocol. DPBs samples (DPB#1, DPB#2, or DPB#3) were harvested when the culture was at an optical density at 600 nm (OD600) of 0.8 to 1.2. Lysis and purification buffers were sequentially applied, and the LPS pellet was dissolved by boiling for 3 min. LPS was quantified using the Limulus Amebocyte Lysate Chromogenic Endotoxin Quantitation Kit (Pierce Biotechnology, Rockford, IL) according to the manufacturer’s protocol. Escherichia coli O111:B4 was used as the standard of known concentration. Ten endotoxin units (EU)/mL equaled approximately 1 ng/ml.
|
study
| 99.94 |
RAW264.7 macrophage cells were cultured in RPMI 1640 containing 10% FBS and 1% antibiotic-antimycotic mixture at 37 °C and 5% CO2. Human fetal osteoblastic cells (hFOB1.19; American Type Culture Collection, Manassas, VA) were cultured in DMEM/F-12 containing 10% FBS and 1% antibiotic-antimycotic mixture. Immortalized human oral keratinocytes (IHOK), immortalized human gingival fibroblasts (IGF), and YD38 human gingival epithelial cells were obtained from the Yonsei University College of Dentistry, Republic of Korea, and all were cultured in DMEM/F12 (3:1 ratio) as previous detailed . Mouse bone marrow-derived macrophages (BMMs) were isolated from the tibias of 4-week-old ICR male mice using Histopaque density gradient centrifugation. BMMs were cultured in α-MEM containing 10% FBS, M-CSF (30 ng/ml), and a 1% antibiotic-antimycotic mixture.
|
study
| 100.0 |
In vitro susceptibility was assessed using the disc diffusion method. Briefly, the bacterial suspension in agarose solution was inoculated on BHI agar plates, and the gel was allowed to solidify completely at room temperature. Whatman filter discs with DMSO, ampicillin (Amp, 10 μg/disc), or EETC (5 μg, 10 μg/disc) were placed on the plates and cultured overnight at 37 °C and 5% CO2. Susceptibility was assessed using linear fitting of the squared radius (diameter in mm) of the inhibition zones. Ampicillin was used for comparing the assay results. DMSO (0.01%) was used as the control.
|
study
| 100.0 |
Cells (1 × 104 cells/well) were added to wells of a 96-well culture plate. After 24 h, the fluid was replaced with complete medium containing EETC and incubation continued for 24 h. Cell viability was measured by the MTT assay, which is based on the ability of viable cells to convert soluble MTT into an insoluble dark blue formazan. MTT solution (5 mg/ml) was added to each well and the plate was incubated at 37 °C for 4 h. The purple formazan product was dissolved with 200 μl DMSO and the optical density at 570 nm was determined with a microplate reader (Bio-Rad, Hercules, CA).
|
study
| 99.94 |
Concentration of human PGE2 was measured by an ELISA kit (R&D Systems) according to the manufacturer’s protocol. Cells (1 × 105 cells/well) were cultured in complete medium in wells of a 6-well plate. After being washed with PBS, the cells were exposed to serum-free medium containing LPS (1 μg/ml) and/or EETC (10 mg/ml) for 24 h. The culture medium was collected by centrifugation at 1,500 rpm for 10 min and was examined by ELISA. DPB#1, DPB#2, and DPB#3 were independently co-cultured with RAW264.7 macrophages, IHOK keratinocytes, IGF gingival fibroblasts, YD38 gingival epithelial cells. Cultured media were harvested by centrifugation and used to determine the level of PGE2. LPS extracted from the three DPB samples (DPB#1-LPS, DPB#2-LPS, and DPB#3-LPS) were also treated instead of DPB.
|
study
| 100.0 |
Total RNA was isolated using the Trizol (Invitrogen, Carlsbad, CA). Single-stranded cDNA was transcribed from the RNA using Promega’s reverse transcription system (Madison, WI). Then PCR was performed with cDNA in a reaction mixture containing 25 mM magnesium chloride (MgCl2), dNTPs, reverse and forward primers, and Taq polymerase (Takara Bio, Shiga, Japan). The following primers were used for PCR: F-COX2, 5′-ATGACTTCCAAGCTGGCCGT-3′ and R-COX2, 5′-CCTCTTCAAAAACTTCTCCACACC-3′ (annealing temperature; 57 °C, PCR product size; 305 base pair): F-RANKL, 5′-GCCAGTGGGAGATGTTAG-3′ and R-RANKL, 5′-TTAGCTGCAAGTTTTCCC-3′ (annealing temperature; 48 °C, PCR product size; 486 base pair): F-OPG, 5′-GGGGACCACAATGAACAAGTTG-3′ and R-OPG, 5′-AGCTTGCACCACTCCAAATCC-3′ (annealing temperature; 55 °C, PCR product size; 409 base pair): F-GAPDH, 5′-CCCCCTACTGCCCACTGCCACCAC-3′ and R-GAPDH, 5′-TCCATCCACTATGTCAGCAGGTCC-3′ (annealing temperature; 52 °C, PCR product size; 420 base pair). The amplified PCR product was electrophoresed on a 2% agarose gel in 1× Tris-Borate-EDTA buffer containing ethidium bromide and visualized using Quantity One software and the Gel Doc 2000 system (Bio-Rad).
|
study
| 99.9 |
Inflammatory cytokine profiles were measured using a Human Inflammation Array C3 Kit (RayBiotech, Norcross, GA) according to the manufacturer’s protocol. Briefly, DPB-LPS (1 μg/ml) and/or EETC (10 mg/ml) was added in culture medium and harvested after 24 h treatment for conditioned medium (CM). Cytokine array membranes were blocked with blocking buffer and incubated with equal protein amounts of CM for 24 h. After extensive sequential washing with Buffer I and Buffer II, the membrane was reacted with a cocktail of biotin-conjugated antibodies against different individual cytokines. The membrane were washed again and reacted with horseradish peroxidase (HRP)-conjugated streptavidin. Relative protein expression was detected by the enhanced chemiluminescence (ECL) system. Densitometric values were quantified using TINA-program software.
|
study
| 100.0 |
Before application to the array, the protein concentration of the CM was normalized by dilution with serum-free media. Then CM was incubated for 24 h with the Proteome Profiler Human Protease Array Kit (R&D Systems). The relative expression levels of the proteases were determined according to the manufacturer’s protocol, and signal intensities were compared using Quantity One software and the Gel Doc 2000 system (Bio-Rad).
|
study
| 99.94 |
Fluorescein isothiocyanate (FITC)-conjugated gelatin matrix-coated coverslips were prepared as described previously . After the coverslips were quenched for 1 h with complete media at 37 °C, the cells were plated and cultured in medium with DPB-LPS (1 μg/ml) and/or EETC (10 mg/ml). Cells were fixed with 4% paraformaldehyde followed by permeabilization with 0.5% Triton X-100/PBS. Dark areas lacking fluorescence on the coverslips were observed with a LSM 510 META confocal laser scanning microscope (Carl Zeiss, Oberkochen, Germany).
|
study
| 99.94 |
Mouse BMMs (5 × 104 cells/well) were plated and cultured in α-MEM complete media containing M-CSF (30 ng/ml), sRANKL (10 ng/ml or 100 ng/ml), DPB-LPS (1 μg/ml), and/or EETC (10 μg/ml) for 7 days with replacement with fresh medium every second day. The cells were fixed with 4% paraformaldehyde for 10 min. Cells were reacted with the Acid Phosphatase, Leukocyte (TRAP) kit (Sigma-Aldrich) according to the manufacturer’s instruction. The number of TRAP-positive multinucleated cells (≥3 nuclei) were counted as osteoclasts per well. Reaction with only M-CSF was performed for control.
|
study
| 100.0 |
Osteo Assay Surface Polystyrene Stripwells (Corning, Corning, NY) were used to observe pit formation as a measure of osteoclast activity. Mouse BMMs (5 × 104 cells/well) were plated on stripwells and cultured in α-MEM complete media containing M-CSF (30 ng/ml), sRANKL (10 ng/ml or 100 ng/ml), DPB-LPS (1 μg/ml), and/or EETC (10 μg/ml). Cultures were fed every 2 days with fresh medium. After a 15-days incubation period, all remaining cells were lysed using 5% sodium hypochlorite solution. Images of the resorbed pits were obtained under light microscopy.
|
study
| 100.0 |
The statistical analysis was conducted using InStat™ statistical software (GraphPad Software, San Diego, CA). Data are expressed as mean ± standard errors. Asterisks were used to graphically indicate the statistical significance. The statistical significance of differences between groups was analyzed via repeated measures of one-way ANOVA. P values of <0.05 were considered significant.
|
study
| 99.8 |
Using the disc diffusion assay, we assessed the extent to which the growth of S. mutans, A. actinomycetemcomitans, and dental plaque bacteria (DPB#1, DPB#2, and DPB#3) was inhibited after EETC treatment. As shown in Fig. 1, ampicillin, which has a broad spectrum of anti-bacterial activity against certain gram-positive, gram-negative, and anaerobic bacteria , inhibited the growth of S. mutans but had negligible effect on the growth of DPBs (DPB#1, DPB#2, or DPB#3) and A. actinomycetemcomitans. EETC effectively suppressed the growth of S. mutans, A. actinomycetemcomitans, and DPB, its antibacterial effect on S. mutans was not as pronounced as ampicillin. The degree of inhibition caused by EETC increased with concentration. Growth inhibition zones were measured on bacterial culture plates after treatment with ampicillin or EETC (Table 1). MIC of EETC against the DPB samples ranged from 32 to 64 μg/ml.Fig. 1EETC suppresses bacterial growth. Inhibitory effect of EETC on the growth of Streptococcus mutans (S. mutans), Aggregatibacter actinomycetemcomitans (A. actinomycetemcomitans), and different types of dental plaque bacteria (DPB#1, DPB#2, and DPB#3) compared with ampicillin (Amp). The data shown are representative of three independent experiments Table 1Antibacterial effect of EETC against plaque bacteriaCompoundConcentration (μg/disk)Size of clear zone (disk margin, mm) S. mutants A. actinomycetemcomitans 1DPB#1 1DPB#2 1DPB#3Control−3 -----Ampicillin1015.5 ± 0.21b -0.1 ± 0.11-- 2EETC53.8 ± 0.19b 3.7 ± 0.03a 3.2 ± 0.03a 2.7 ± 0.09b 3.9 ± 0.18b 107.2 ± 0.07b 7.5 ± 0.02b 6.9 ± 0.04b 5.3 ± 0.05b 7.4 ± 0.06b 1DPB; dental plaque bacteria, 2EETC; ethanol extracts of Terminalia chebula, 3No inhibition(a P < 0.05, b P < 0.01)
|
study
| 100.0 |
EETC suppresses bacterial growth. Inhibitory effect of EETC on the growth of Streptococcus mutans (S. mutans), Aggregatibacter actinomycetemcomitans (A. actinomycetemcomitans), and different types of dental plaque bacteria (DPB#1, DPB#2, and DPB#3) compared with ampicillin (Amp). The data shown are representative of three independent experiments
|
study
| 100.0 |
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