[Effect of different surface treatments on the crystal structure and properties of zirconia]

OBJECTIVE

To investigate the effects of 3 surface different treatments on the crystal structure, shear bond strength,roughness value and flexural strength of zirconia.

METHODS

The zirconia specimens were prepared and randomly divided into 4 groups and received the following treatments: (1) blank control group,the specimens without treatments; (2)sandblasting with alumina group, sandblasting the specimens with 110 μm alumina particles for 21 s as working pressure 0.25 MPa and working distance 10 mm; (3)laser etching group, coating the surface of the specimens with graphite powder and using Er:Yttrium Aluminum Garnet (Er:YAG) laser to irradiate the surface 30 s; (4) hot-etching group, putting the specimens in a closed reactor within a 1:1 mixture of 40% (mass traction) nitric acid and 68%(mass traction) hydrofluoric acid liquid, the reaction of 30 min in a water bath at 100 degrees centigrade. The changes of crystal structure, shear bond strength(SBS) and flexural strength of zirconia after different surface treatments were tested.

RESULTS

The X-ray diffractometer (XRD) patterns showed that the volume percentage of monoclinic phase of the 4 groups was 0.91%, 12.50%, 6.64% and 17.81% respectively. The roughness value for the four groups were as follows: blank control group,(0.29±0.01) μm; sandblasting with alumina group, (1.05±0.11) μ m; laser etching group, (0.73±0.04) μm; hot-etching group, (1.31±0.06) μm, respectively(P<0.05). Mean SBS was (7.09±0.46) MPa in blank control group, (12.14±1.51) MPa in sandblasting with alumina group, (8.82±0.74) MPa in laser etching group and (11.97±0.99) MPa in hot-etching group. There was no statistically significant difference between sandblasting with alumina group and hot-etching group (P>0.05), but the difference between the other groups were statistically significant(P<0.05). Mean three-point bending was (933.70±44.13) MPa in blank control group, (850.95±60.66) MPa in sandblasting with alumina group, (771.53±68.08) MPa in laser etching group and (766.27±57.49) MPa in hot-etching group. There was no statistically significant difference between sandblasting with alumina group and hot-etching group (P>0.05), but the difference between the other groups were statistically significant (P<0.05).

CONCLUSION

After different surface treatments, the surface of zirconia has changed from tetrago-nal to monoclinic phases in varying degrees. In addition, surface treatments could improve the bond strength of zirconia to resin cement, and also lead to a decrease in the flexural strength of zirconia.

Preliminary study of 1940 nm thulium laser usage in peroral endoscopic myotomy for achalasia

Esophageal achalasia is a type of motility disorder characterized by incomplete relaxation of lower esophageal sphincter (LES) and absence of esophageal peristalsis. Peroral endoscopic myotomy (POEM) is a new treatment option for achalasia that is less invasive, more effective, and safe as compared to surgery. High-frequency electrotome is commonly used in POEM, but takes longer time to make the tunnel in the esophagus and causes many complications. The thulium laser decreases the risk of bleeding and perforation in endoscopy but has not been reported in digestive diseases, especially in POEM. Therefore, the aim of this study is to evaluate the feasibility of the 1940 nm thulium laser in POEM. From March 2015 to August 2015, five patients with achalasia at the Digestive department, Beijing Friendship Hospital, Capital Medical University, Beijing, China were included. Before the procedure, the patients' gender, age, and duration of symptoms were recorded. Eckardt symptom score and LES thickness, which measured by endoscopic ultrasonography, were recorded. While the subtypes of achalasia (according to the Chicago classification), lower esophagus sphincter resting pressure (LESRP) and integrated relaxation pressure (IRP) were measured by HRM for all patients. Barium esophagram was also used to rule out anatomical lesions, esophageal varices, or neoplasia, which may cause similar symptoms. All examinations were performed one week before POEM. POEM was performed with the 1940 nm thulium laser under general anesthesia. Eckardt score, procedure duration, myotomy length, and complications were recorded one week after POEM. All the patients were followed-up at two weeks and four weeks after POEM. POEM was successfully performed in all five patients. The mean age of the patients was 38.8 years (24-54 years). Achalasia subtypes were type I (n = 1), II (n = 2), and III (n = 2). The operation duration was 186, 180, 111, 75, and 126 minutes for the five cases. Pre/postprocedure Eckardt scores were 3/0, 7/0, 5/1, 6/0, and 9/0. Pre/postprocedure LESRP (mmHg) were 45.3/26.4, 18.0/1.1, 25.8/10.4, 16.5/11.2, and 24.2/20.8. Pre/postprocedure IRP (mmHg) were 27.3/15.5, 15.4/4.2, 5.7/6.8, 15.5/10.1, and 13.1/14, respectively. No adverse events occurred during the procedure. After POEM, subcutaneous emphysema occurred in case 1 on the first day, which relieved spontaneously after two days without special intervention. Infection occurred in case 5 on the day of POEM was healed with antibiotics three days later. The 1940 nm thulium laser is feasible for POEM procedure. Further studies are needed to determine whether the 1940 nm thulium laser is better than high-frequency electrotome.

Initial empiric antibiotic therapy for community-acquired pneumonia in Chinese hospitals

OBJECTIVES

Studies on treatment of community-acquired pneumonia (CAP) in China are scarce. We performed a study to investigate empiric antibiotic practices for patients hospitalized with CAP in China and the risk factors for treatment failure.

METHODS

Data were collected from a national Chinese hospitalization database. Adult patients who were diagnosed with CAP between 1 October 2014 and 30 September 2015 were identified. We studied initial empiric antibiotic regimens, microbiologic sampling, treatment failure, in-hospital mortality and length of hospital stay.

RESULTS

We included 18 043 adult patients from 185 hospitals who met all the study inclusion criteria. The most common initial antibiotic regimen for CAP was monotherapy with a fluoroquinolone (14.8%, 2671/18 043). The most common initial antibiotic (used alone or in combination with other antibiotics) was levofloxacin (15.7%, 4597/29 278 (this denominator represents the total number of initial antibiotics)). The microbiologic sampling rate was 26.9% (4851/18 043). A total of 4050 (22.4%) of 18 043 patients experienced treatment failure. Multivariate logistic regression demonstrated that older age, male sex, coexisting lung cancer and use of regimens not covering atypical pathogens were risk factors for treatment failure. In-hospital mortality was 2.1% (380/18 043). The median hospital length of stay was 11 days (interquartile range, 8-15 days).

CONCLUSIONS

Patients receiving Chinese guideline-adherent regimens had better outcomes, and atypical pathogen active regimens were associated with a lower treatment failure rate and shorter length of hospital stay.

Comparison of effectiveness and safety between conbercept and ranibizumab for treatment of neovascular age-related macular degeneration. A retrospective case-controlled non-inferiority multiple center study

Purpose

To compare the efficacy and safety of conbercept and ranibizumab when administered according to a treat-and-extend (TREX) protocol for the treatment of neovascular age-related macular degeneration (AMD) in China.

Patients and methods

Between May 2014 and May 2015, 180 patients were treated in a 1 : 1 ratio using conbercept or ranibizumab from four hospitals. Patients received either conbercept 0.5 mg or ranibizumab 0.5 mg intravitreal injections. Follow-up time was 1 year and treated based on a TREX approach. Main outcomes and measures include best-corrected visual acuity (BCVA), using Early Treatment Diabetic Retinopathy Study (ETDRS); number of injections; central retinal thickness (CRT); and leakage of choroidal neovascularization before and after the treatment was analyzed by fluorescein fundus angiography and indocyanine green angiography.

Results

The 1-year visit was completed by 168 (93.3%) of patients. Mean BCVA was equivalent between two cohorts, and were improved by 12.7±7.770 and 12.3±7.269 letters in the conbercept and ranibizumab cohorts, respectively (P=0.624). There was no significant difference in measured CRT, with a mean decrease of 191.5 μm for conbercept and 187.8 μm for ranibizumab (P=0.773). There was a statistically significant difference (P=0.001) between the drugs regarding the number of treatments: 7.4 for conbercept and 8.7 for ranibizumab. The difference in the distribution of injection intervals was statistically significant between two groups (P=0.011). During the study, there were no cases of endophthalmitis or intraocular inflammation.

Conclusion

Both drugs had equivalent effects in visual and anatomic gains at 1 year when administered. In the conbercept group, longer treatment intervals were achieved with more patients.

Physicochemical properties and cytotoxicity of an experimental resin-based pulp capping material containing the quaternary ammonium salt and Portland cement

AIM

To evaluate in vitro the physicochemical properties, cytotoxicity and calcium phosphate nucleation of an experimental light-curable pulp capping material composed of a resin with antibacterial monomer (MAE-DB) and Portland cement (PC).

METHODOLOGY

The experimental material was prepared by mixing PC with a resin containing MAE-DB at a 2 : 1 ratio. Cured pure resin containing MAE-DB served as control resin. ProRoot MTA and Dycal served as commercial controls. The depth of cure, degree of monomer conversion, water absorption and solubility of dry samples, calcium release, alkalinizing activity, calcium phosphate nucleation and the cytotoxicity of materials were evaluated. Statistical analysis was carried out using anova followed by Tukey's HSD test (equal variance assumed) or Tamhane test (equal variance not assumed) and independent-samples t-tests.

RESULTS

The experimental material had a cure depth of 1.19 mm, and the mean degree of monomer conversion was 70.93% immediately post-cure and 88.75% at 24 h post-cure. The water absorption of the experimental material was between those of MTA and Dycal, and its solubility was significantly less (P < 0.05) than that of Dycal and higher than that of MTA. The experimental material exhibited continuous calcium release and an alkalinizing power between those of MTA and Dycal throughout the test period. Freshly set experimental material, control resin and all 24-h set materials had acceptable cytotoxicity. The experimental material, MTA and Dycal all exhibited the formation of apatite precipitates after immersion in phosphate-buffered saline.

CONCLUSIONS

The experimental material possessed adequate physicochemical properties, low cytotoxicity and good calcium phosphate nucleation.

Unilateral occipital nerve stimulation for bilateral occipital neuralgia: a case report and literature review

Objectives

The aim of this study is to present a case of successful relief of bilateral occipital neuralgia (ON) using unilateral occipital nerve stimulation (ONS) and to discuss the possible underlying mechanisms.

Materials and methods

We present the case of a 59-year-old female patient with severe bilateral ON treated with unilateral ONS. We systematically reviewed previous studies of ONS for ON, discussing the possible mechanisms of ONS in the relief of ON.

Results

The patient reported complete pain relief after consistent unilateral ONS during the follow-up period. The underlying mechanisms may be linked to the relationship between pain and several brain regions, including the pons, midbrain, and periaqueductal gray.

Conclusion

ONS is an effective and safe option for treating ON. Future studies will be required to clarify the mechanisms by which unilateral occipital stimulation provided relief for bilateral neuralgia in this case.

Significantly enhanced creep resistance of low volume fraction in-situ TiBw/Ti6Al4V composites by architectured network reinforcements

We present a new class of TiBw/Ti6Al4V composites with a network reinforcement architecture that exhibits a significant creep resistance compared to monolithic Ti6Al4V alloys. Creep tests performed at temperatures between 773 K and 923 K and stress range of 100 MPa-300 MPa indicate both a significant improvement of the composites creep resistance due to the network architecture made by the TiB whiskers (TiBw), and a decrease of the steady-state creep rates by augmenting the local volume fractions of TiBw in the network region. The deformation behavior is driven by a diffusion-controlled dislocation climb process. Moreover, the activation energies of these composites are significantly higher than that of Ti6Al4V alloys, indicating a higher creep resistance. The increase of the activation energy can be attributed to the TiBw architecture that severely impedes the movements of dislocation and grain boundary sliding and provides a tailoring of the stress transfer. These micromechanical mechanisms lead to a remarkable improvement of the creep resistance of these networked TiBw/Ti6Al4V composites featuring the special networked architecture.

[Effect of balloon dilation tracheoplasty in the management of acquired subglottic stenosis in children]

Objective:To assess the efficiency and safety of balloon dilation tracheoplasty technique in the management of acquired subglottic stenosis in children. Method:Twenty-three cases were diagnosed as acquired subglottic stenosis by chest CT scan and bronchoscpy，and received the treatment of the balloon dilatation tracheoplasty.The data about the efficiency，complication and prognosis of the treatment were collected. Result:In the 23 cases，6 of All 11 patients with tracheotomy were decannulated,11 patients were successfully managed without tracheotomy，1 patients received laryngotracheal reconstruction(LTR) surgery, 5 cases were still under observation. The overall response rate was 73.91%.All cases were divided into three stages according to Cotton stage system:1 cases were stage Ⅰ stenosis，6 cases were stage Ⅱ and 16 cases were stage Ⅲ. The response rate was 100.00%，83.33%，and 68.75% respectively. The most common complication in the balloon dilatation tracheoplasty was restenosis. Restenosis occurs in 12（52.17%） cases who received more than 1 dilation procedures in this study. Over all average dilation times is 1.87. Eight cases(88.9%) of 9 in fresh leision group were recoverd, the average dilation time is 1.22; 8 cases (57.14%) of 14 in old leision group were recoverd, the average dilation time is 2.23. The average dilation time between two group is significant(P<0.05). Conclusion:Subglottic stenosis in pediatric patients can be successfully managed with balloon dilation tracheoplasty. In patients without prior tracheotomy, tracheotomy can often be safely avoided with appropriate postoperative management.

[Control study of total percutaneous access with preclose technique versus open femoral artery exposure for endovascular aneurysm repair]

OBJECTIVE

To compare total percutaneous access using preclose technique with femoral artery cut-down in endovascular aneurysm repair (EVAR) and assess the safety and feasibility of preclose technique.

METHODS

In the study, 81 cases undergoing EVAR from Dec. 2011 to Nov. 2014 in Peking University People's Hospital were retrospectively reviewed. Preoperative CT angiography (CTA) showed presence of infrarenal abdominal aortic aneurysm or descending aortic aneurysm in all the cases. The maximum diameter of aneurysm >4.5 cm met the indications for surgical treatment. The conditions of bilateral femoral artery and iliac artery CTA showed were good, and there was no moderate or severe stenosis, nor was there any severe calcification in anterior wall of femoral artery. Not only were the cases fit for percutaneous endovascular aortic aneurysm repair (PEVAR), but also feasible with open endovascular aneurysm repair (OEVAR). According to the intention of the patients about the surgical incision, the cases were divided into group PEVAR and group OEVAR. The data of the general situation, operation time, blood loss, technical success rate, length of hospital stay after procedure and wound complications were analyzed statistically.

RESULTS

In the study, 44 cases (78 incisions) were enrolled in group PEVAR and 37 cases (65 incisions) in group OEVAR. There was no significant difference between the two groups in age, gender, body mass index (BMI), accompanying diseases, average number of stents and outer diameter of stent delivery system. Average operation time of group PEVAR was less than that of group OEVAR [(119.1±102.0) min vs. (163.6±61.9) min, P=0.025]. The blood loss in group PEVAR was less than that in group OEVAR [(64.7±97.0) mL vs. (98.6±88.3) mL], but there was no significant difference (P=0.106). There was no difference in the technical success rate (94.9% vs.95.4%, P=1.000). The average length of hospital stay after procedure was significantly shorter in group PEVAR [(7.8±2.8) d vs.(12.3±7.2) d, P<0.001]. There were 2 cases with subcutaneous hematoma of wound in group PEVAR and 7 cases of wound complications that occurred in group OEVAR including 3 cases with lymphatic leakage, 3 cases with lower limb ischemia and 1 case with subcutaneous hematoma. The analysis showed that PEVAR could reduce the wound complications (2.6%vs.10.8%), but there was no significant difference between the two groups (P=0.079).

CONCLUSION

Using preclose technique in EVAR is safe and effective. It can shorten the operation time and length of hospital stay after procedure.

Controllable two-scale network architecture and enhanced mechanical properties of (Ti5Si3+TiBw)/Ti6Al4V composites

Novel Ti6Al4V alloy matrix composites with a controllable two-scale network architecture were successfully fabricated by reaction hot pressing (RHP). TiB whiskers (TiBw) were in-situ synthesized around the Ti6Al4V matrix particles, and formed the first-scale network structure (FSNS). Ti₅Si₃ needles (Ti₅Si₃) precipitated in the β phase around the equiaxed α phase, and formed the secondary-scale network structure (SSNS). This resulted in increased deformation compatibility accompanied with enhanced mechanical properties. Apart from the reinforcement distribution and the volume fraction, the ratio between Ti₅Si₃ and TiBw fraction were controlled. The prepared (Ti₅Si₃ + TiBw)/Ti6Al4V composites showed higher tensile strength and ductility than the composites with a one-scale microstructure, and superior wear resistance over the Ti6Al4V alloy under dry sliding wear conditions at room temperature.

[Effect of standardized treatment on reactivity of toe microcirculation in patients with type 2 diabetes mellitus]

OBJECTIVE

To evaluate the effect of standardized treatment on reactivity of the lower limb terminal microcirculation in patients with type 2 diabetes mellitus (T2DM) by high frequency ultrasound combined with warm bath.

METHODS

A total of 66 patients with T2DM were collected from June 2014 to May 2015 in the Second Affiliated Hospital of Wenzhou Medical University.According to the vascular complications , the patients were divided into group A without complications (36 cases)and group B with complications (30 cases). Hemodynamic parameters such as peak systolic velocity(PSV), end-diastolic velocity(EDV) and resistance index(RI) of the right plantar digital artery on fibular side of the 1st toe were acquired through Doppler in all subjects.Then the above operation were performed repetitively on all subjects after the right foot was immersed in 40 ℃ warm water for 5 minutes.The change rates of PSV, EDV and RI were calculated after warm bath.All subjects were examined again after three months treatment .The growth rates of the change rate of PSV, EDV and RI were calculated after treatment.All parameters were analyzed.

RESULTS

The change rates of the parameters in group B before and after treatment were lower than those of group A, before treatment (0.108±0.077 vs 0.184±0.091, P=0.037, 0.184±0.101 vs 0.380±0.167, P=0.002, 0.007±0.004 vs 0.015±0.008, P=0.028 7), after treatment (0.155±0.111 vs 0.421±0.138, 0.287±0.108 vs 0.794±0.286, 0.012±0.008 vs 0.039±0.014, P=0.000); the post treatment growth rates of the change rates of the parameters in group B were all less than those of group A (0.414±0.303 vs 2.192±2.673, P=0.048, 0.660±0.406 vs 1.422±1.075, P=0.042, 0.633±0.830 vs 2.191±2.269, P=0.048). The change rates of the parameters in two groups after treatment were higher than those before treatment (all P<0.05).

CONCLUSION

Warm bath test can be used to detect change degree of hemodynamic parameters in patients with T2DM so as to evaluate reactivity of blood microcirculation, which has a certain clinical application value in treatment.

Seasonal changes of androgen receptor, estrogen receptors and aromatase expression in the medial preoptic area of the wild male ground squirrels (Citellus dauricus Brandt)

The wild ground squirrel is a typical seasonal breeder. In this study, using RT-PCR, western blot and immunohistochemistry, we investigated the mRNA and protein expressions of androgen receptor (AR), estrogen receptors a and β (ERα and ERβ) and aromatase cytochrome P450 (P450arom) in the medial preoptic area (MPOA) of hypothalamus of the wild male ground squirrel during the breeding season (April), the non-breeding season (June) and pre-hibernation (September). AR, ERα, ERβ and P450arom protein/mRNA were present in the MPOA of all seasons detected. The immunostaining of AR and ERα showed no significant changes in different periods, whereas ERβ and P450arom had higher immunoreactivities during the breeding season and pre-hibernation when compared to those of the non-breeding season. Consistently, both the protein and mRNA levels of P450arom and ERβ were higher in the MPOA of pre-hibernation and the breeding season than in the non-breeding season, whereas no significant difference amongst the three periods was observed for AR and ERα levels. These findings suggested that the MPOA of hypothalamus may be a direct target of androgen and estrogen. Androgen may play important regulatory roles through its receptor and/or the aromatized estrogen in the MPOA of hypothalamus of the wild male ground squirrels.

The potential protective role of hepatitis B virus infection in pristane-induced lupus in mice

OBJECTIVE

The objective of this study was to investigate whether hepatitis B virus (HBV) infection plays a role in the regulation of autoimmunity for systemic lupus erythematosus (SLE).

METHOD

A total of 21 female BALB/c mice and 21 female HBV transgenic BALB/c mice aged two months were randomly divided into four groups: BALB/c mice, HBV(Tg) mice, pristane-injected BALB/c mice, and pristane-injected HBV(Tg) mice. BALB/c mice and HBV(Tg) mice were given an intraperitoneal injection of 0.5 ml normal saline, and the mice in the other two groups were given an intraperitoneal injection of 0.5 ml pristane. ANA and anti-dsDNA levels in serum were detected by indirect immunofluorescence. Interleukin 2 (IL-2), IL-4, IL-6, IL-17, and TNF-α were measured by Luminex technology. The serum BAFF level was measured using an Elisa kit. Twenty-four weeks after pristane administration, kidneys were removed, dissected, and stained with hematoxylin and eosin and periodic-acid Schiff.

RESULT

At six months after injecting, the ANA titers in pristane-injected HBV(Tg) mice were significantly lower than pristane-injected BALB/c mice. IL-17, TNF-α, and BAFF levels were significantly higher in pristane-injected BALB/c mice than BALB/c mice and pristane-injected HBV(Tg) mice. IL-2, IL-4, and IL-6 levels were much higher in pristane-injected HBV(Tg) mice than pristane-injected BALB/c mice. In pristane-injected HBV(Tg) mice and HBV(Tg) mice, fewer glomerulonephritis changes were found in the kidneys.

CONCLUSIONS

Our results showed that the incidence of SLE was much lower in HBV(Tg) mice, and that HBV infection helped the SLE mice survive high levels of inflammatory cytokines and severe renal damage. All these findings demonstrated the protective role of HBV in SLE patients via the immunoregulatory networks of the cytokines.

High-bandwidth uni-traveling carrier waveguide photodetector on an InP-membrane-on-silicon platform

A uni-traveling carrier photodetector (UTC-PD), heterogeneously integrated on silicon, is demonstrated. It is fabricated in an InP-based photonic membrane bonded on a silicon wafer, using a novel double-sided processing scheme. A very high 3 dB bandwidth of beyond 67 GHz is obtained, together with a responsivity of 0.7 A/W at 1.55 μm wavelength. In addition, open eye diagrams at 54 Gb/s are observed. These results promise high speed applications using a novel full-functionality photonic platform on silicon.

Knockdown of JMJD1C, a target gene of hsa-miR-590-3p, inhibits mitochondrial dysfunction and oxidative stress in MPP+-treated MES23.5 and SH-SY5Y cells

MicroRNAs have been shown to be closely related to many neurodegenerative disorders. The present study focuses on the role of hsa-miR-590-3p and its function in Parkinson's disease (PD). Our study showed a remarkable down-regulation of miR-590-3p expression in the 1-methyl-4 phenylpyridinium (MPP+)-treated MES23.5 and SH-SY5Y cells. Furthermore, JMJD1C was identified as a target gene of miR-590-3p in humans via the luciferase reporter assay. Our study also demonstrated that up-regulation of miR-590-3p and knockdown of JMJD1C increased the expression of peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α) and the downstream targets of PGC-1α, including nuclear respiratory factor 1 (NRF-1) and mitochondrial transcription factor A (TFAM), which are the key genes regulating mitochondrial function. Also, the expression of heme oxygenase-1 (HO-1), NAD (P) H quinone oxidoreductase-1 (NQO-1) and γ-glutamylcysteine synthetase (γ-GCS) involved in anti-oxidation was increased. Moreover, there was a significant increase in the total cellular ATP with an associated decrease in levels of ROS in the absence of JMJD1C. Taken together, these results show that miR-590-3p plays an important role in the pathogenesis of PD, which may be further regarded as a therapeutic target.

Elevated gold ellipse nanoantenna dimers as sensitive and tunable surface enhanced Raman spectroscopy substrates

We demonstrate large area arrays of elevated gold ellipse dimers with precisely controlled gaps for use as sensitive and highly controllable surface enhanced Raman scattering (SERS) substrates. The enhanced Raman signal observed with SERS arises from both localized and long range plasmonic effects. By controlling the geometry of a SERS substrate, in this case the size and aspect ratio of individual ellipses, the plasmon resonance can be tuned in a broad wavelength range, providing a method for designing the response of SERS substrates at different excitation wavelengths. Plasmon effects exhibited by the elevated gold ellipse dimer substrates are also demonstrated and confirmed through finite difference time domain (FDTD) simulations. A plasmon resonance red shift with an increase of the ellipse aspect ratio is observed, allowing systematic control of the resulting SERS signal intensity. Optimized elevated ellipse dimer substrates with 10 ± 2 nm gaps exhibit uniform SERS enhancement factors on the order of 10(9) for adsorbed p-mercaptoaniline molecules.

Epigenetic Modifications of Histones in Periodontal Disease

Periodontitis is a chronic infectious disease driven by dysbiosis, an imbalance between commensal bacteria and the host organism. Periodontitis is a leading cause of tooth loss in adults and occurs in about 50% of the US population. In addition to the clinical challenges associated with treating periodontitis, the progression and chronic nature of this disease seriously affect human health. Emerging evidence suggests that periodontitis is associated with mechanisms beyond bacteria-induced protein and tissue degradation. Here, we hypothesize that bacteria are able to induce epigenetic modifications in oral epithelial cells mediated by histone modifications. In this study, we found that dysbiosis in vivo led to epigenetic modifications, including acetylation of histones and downregulation of DNA methyltransferase 1. In addition, in vitro exposure of oral epithelial cells to lipopolysaccharides resulted in histone modifications, activation of transcriptional coactivators, such as p300/CBP, and accumulation of nuclear factor-κB (NF-κB). Given that oral epithelial cells are the first line of defense for the periodontium against bacteria, we also evaluated whether activation of pathogen recognition receptors induced histone modifications. We found that activation of the Toll-like receptors 1, 2, and 4 and the nucleotide-binding oligomerization domain protein 1 induced histone acetylation in oral epithelial cells. Our findings corroborate the emerging concept that epigenetic modifications play a role in the development of periodontitis.